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The collective dynamics of active biopolymers is crucial for many processes in life, such as cellular motility, intracellular transport, and division. Recent experiments revealed fascinating self-organized patterns of diverse active filaments, while an explicit parameter control strategy remains an open problem. Moreover, theoretical studies so far mostly dealt with active chains with uniform stiffness, which are inadequate in describing the more complicated class of polymers with varying stiffness along the backbone. Here, using Langevin dynamics simulations, we investigate the collective behavior of active chains with homogeneous and heterogeneous stiffness in a comparative manner. We map a detailed non-equilibrium phase diagram in activity and stiffness parameter space. A wide range of phase states, including melt, cluster, spiral, polar, and vortex, are demonstrated. The appropriate parameter combination for large-scale polar and vortex formation is identified. In addition, we find that stiffness heterogeneity can substantially modulate the phase behaviors of the system. It has an evident destructive effect on the long-ranged polar structure but benefits the stability of the vortex pattern. Intriguingly, we unravel a novel polar–vortex transition in both homogeneous and heterogeneous systems, which is closely related to the local alignment mechanism. Overall, we achieve new insights into how the interplay among activity, stiffness, and heterogeneity affects the collective dynamics of active filament systems. [ABSTRACT FROM AUTHOR]

The relative errors of virtual cathodes calculated by using the one-dimensional virtual cathode theory are analyzed and discussed. The studies of the error analysis show that the cathode temperature is the major factor affecting the calculated results of virtual cathodes, especially for calculations of the virtual cathode width. The smaller the virtual cathode produced by a hot cathode, the more significant the relative error of the virtual cathode caused by the uncertainties of electron emission parameters. Using the accurate cathode temperature, the potential barrier and the spatial width of virtual cathodes generated by a tungsten filament are calculated with experimental and theoretical electron emission parameters. The calculated results show that there is a strong linear correlation between the potential barrier of the virtual cathode and the heating current of the tungsten filament, which is independent of the electron collection current. With the increase in the heating current, the variation of the virtual cathode width is very sensitive to the relation between the electron collection current and the heating current. [ABSTRACT FROM AUTHOR]

We experimentally demonstrate the in situ characterization of optical micro/nano fibers (MNFs). The MNF (test fiber, TF) is positioned on a microfiber (probe fiber, PF) and simulated for the scattering loss at various PF and TF diameters. The TF is fabricated using chemical etching technique. The PF is a conventional single-mode fiber with an outer diameter of 125 μ m. We measure the scattering loss along the TF axis at various positions i.e., diameters by mounting it on the PF. The diameter profile of the TF is inferred from the measured scattering loss and correlated with its surface morphology measurement. This work demonstrates an effective, low-cost, and non-destructive method for in situ characterization of fabricated MNFs. It can detect and determine the irregularities on the surface of OMNFs. It can also be used to quantify the local evanescent field. Detecting such local points can improve studies that are carried out using these fields in various sensing and related study domains. It is simple to implement and can be accessed by all domains of researchers. [ABSTRACT FROM AUTHOR]

Electrospinning is a cost-effective but very intricate method of producing polymeric nanofibers at room temperature. Unfortunately however, it is extremely difficult to predict the diameter or other properties of the fibers produced via electrospinning a prior. In this paper, we present a new approach to simulate fiber formation during electrospinning. Our work builds on the mathematical framework that was originally developed by Reneker and Yarin in 2000. Our approach incorporates the 3D electrostatic field that surrounds the fiber in a Lagrangian discrete particle tracking algorithm that tracks the trajectory of the fiber in air and predicts its deposition velocity and diameter. We investigate the effects of electrostatic field spatial variation on fiber electrospinning and compare our results with those obtained using a constant electrostatic field, the traditional approach, and with experiments (conducted using polyurethane). We considered three different electrospinning configurations of single-needle-plate-collector, single-needle-drum-collector, and two-needles-drum-collector to investigate how different electrostatic fields impact fiber formation. The computational model developed in this work helps to advance the current state of the art in modeling the electrospinning process. [ABSTRACT FROM AUTHOR]

Electrospinning is an important technique to fabricate nanofibers. In recent years, near-field electrospinning (NFES) has been developed to enhance the control of nanofiber deposition compared to conventional electrospinning, achieved by reducing the operating distance and electric field. This enables the construction of high-aspect ratio 3D structures in a self-aligned, layer-by-layer manner. However, the alignment of fiber deposition can be hindered by charge accumulation in the polymer fibers. Furthermore, a theoretical understanding of the underlying fiber deposition mechanism is still lacking. Herein, we present a numerical model for studying the charge transport, dissipation, and accumulation of NFES polymer fiber deposition. The model reveals that the presence of a trapped state in polymeric materials imposes limitations on the quality of charged fiber deposition. Moreover, the effect of different substrate materials on charge dissipation in fiber deposition is studied. To validate the model, we compare the simulation results with NFES experiments, demonstrating qualitative agreement. We also analyze the effect of the fiber materials and experimental parameters on the printing quality. This model provides an approach to analyze and optimize the operating parameters of NFES to achieve precise and stable nanofiber deposition. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the effect of three different curing protocols based on different ratios of self-curing and light-curing periods on the bond strength and nanoleakage of fiber posts luted with dual-curing selfadhesive cements. Materials and Methods: A total of 48 single-root teeth were endodontically treated and obturated, and an 8-mm post space was prepared with dedicated drills. Specimens were randomly divided into two groups according to the self-adhesive cement employed: group 1 (G1) = PANAVIA SA Plus (Kuraray Noritake), and group 2 (G2) = Bifix SE (VOCO). The specimens were further divided into three subgroups (n = 8 each) according to the light-curing protocol applied: no light-curing (SG1), 20 seconds of light-curing 20 seconds after cement injection (SG2), and 20 seconds of light-curing 120 seconds after cement injection (SG3). Slices of 1-mm thickness were prepared for the pushout test and nanoleakage analyses of the coronal and apical regions after 24 hours of storage in artificial saliva. Results were statistically analyzed with threeway ANOVA and Tukey post hoc tests. Statistical significance was set for P < .05. Results: Three-way ANOVA analysis showed that the factors of cement (P = .02) and curing protocol (P < .001) had a significant influence on bond strength. Tukey post hoc test reported that light-curing 120 seconds after injection showed higher bond strength compared to both no light-curing and photoactivation after 20 seconds. Conclusion: To achieve the highest bond strength with self-adhesive cements, photoactivation with a 120-second delay after mixing is required. There is no difference between light-curing immediately and light-curing 20 seconds after mixing. [ABSTRACT FROM AUTHOR]

In this work, SiBCN fibers with excellent electromagnetic wave (EMW) absorption performance were fabricated using electrospinning technology, followed by curing, pyrolysis, and heat treatment. Microstructure evolution and EMW absorption performance of SiBCN fibers after heat treatment at 1200–1600 °C were investigated. After heat treatment at 1200 °C, the conductive turbostratic C was precipitated from amorphous SiBCN fibers, resulting in minimum reflection loss (RL min) reaching −63 dB and efficient absorption bandwidth (EAB) reaching 5.2 GHz. While turbostratic C and nano-SiC grains were simultaneously precipitated from SiBCN fibers heat treated at 1400 °C, and the RL min reached −67 dB. The excellent EMW absorption performance of SiBCN fibers was mainly attributed to the synergistic effect of conductive loss, dipole polarization, and interfacial polarization. This work can guide the fabrication of high-performance EMW-absorbing ceramic fibers. [ABSTRACT FROM AUTHOR]

In this paper, the heat treatment of alumina fiber was studied. The infiltration agent on the fiber surface was removed after heat treatment at 450 °C for 6 h. TG-DSC, scanning electron microscope, x-ray diffraction, Fourier infrared spectrometer, energy dispersive spectrometer, and patterning were used to analyze the thermal weight loss, fiber surface morphology, crystal structure, and composition of alumina fibers. The results show that the aluminum oxide fiber has excellent temperature resistance and does not undergo crystal phase transformation during thermal weight loss. After heat treatment, the fiber surface infiltration agent ablates and dissolves from the fiber surface, and the internal crystal structure of the fiber remains stable. The tensile testing machine was utilized to test the breaking strength of alumina fiber. The fiber still maintained high strength after heat treatment, and the retention rate of breaking strength was greater than 74%. ZC-90G high insulation resistance measuring instrument and WDY-Ⅱ automatic voltage tester were utilized to analyze the insulation resistivity and breakdown strength of alumina fiber before and after heat treatment. The results show that heat treatment can effectively improve the insulation performance and breakdown strength of alumina fiber. [ABSTRACT FROM AUTHOR]

In this paper, the hydrolysis process of Dichlorohydroxytriazine (NHDT) under alkaline conditions are studied. A qualitative and quantitative method for the determination of HNDT and its hydrolysis products are established, which further clarified the hydrolysis mechanism of NHDT. Under alkaline conditions, the hydrolysis products are mainly compound 4, compound 6 and chloride (Cl−). The hydrolysis rate of NHDT at different NaOH concentration and temperature is studied. This research can be used to guide the high efficiency preparation of low fibrillation Lyocell fiber. According to the quantitative detection of wet abrasion numbers and the qualitative analysis of the fiber by SEM after slapping, it is concluded that the low fibrillation Lyocell fiber is less prone to fibrillation under the combined action of wet state and mechanical force. Due to hydrolysis of the unreacted second chlorine resulting in harmful products on the low fibrillation Lyocell fiber, the fibrillation propensity increased with the increase of storage time. The mechanical properties of low fibrillation Lyocell fiber prepared under different fiber states are studied. The tensile breaking strength of low fibrillation Lyocell fiber prepared in the form of sequentially arranged fiber bundles are better, which is closely related to the fiber surface. [ABSTRACT FROM AUTHOR]

In this paper, we investigate the scenarios in which a holonomic versus a non-holonomic frame description of gravity theories are equivalent. It turns out that classically, the equivalence holds in a way that is independent of the particular dynamics and/or spacetime dimension. This includes general metric-affine dynamics. A global bundle-theoretical investigation is carried out, uncovering the equivalence principle as the culprit. The equivalence holds as long as the equivalence principle holds. This is not something to be expected when non-invertible configurations of the vielbein field are taken into account. In such cases, the gauge-theoretical description of gravity “unsolders” from spacetime, and one has to decide if gravity is spacetime geometry or an internal gauge theory. [ABSTRACT FROM AUTHOR]

Needled preform and its composite using felt and base cloth stacked needled have small fiber volume fraction and relatively weak mechanical properties, which are difficult to meet the service requirements of structural and functional integrated components of high‐speed aircraft. Responding to this issue, this paper proposed a new method for preparing high load‐bearing needled composite preform based on ordered short fiber network needling. The high load‐bearing needled preforms were prepared by designing different structural parameters of ordered short fiber network and forming process parameters, and then preform structure was characterized and mechanical properties were tested. The results showed that using ordered short fiber network as carrier of the short fibers, the formed needled fiber bundles were longer and denser, volume content of needled fiber bundles and mechanical properties of needled preform were greatly improved, and needled fiber bundles volume content of ordered short fiber network reinforced needled preform was 1.5 times and 46.3 times that of half‐cut cloth and felt respectively. Compared with traditional felt needled preform and half‐cut cloth needled preform, the interlaminar peeling strength of the ordered short fiber network reinforced needled preform increased by up to 246.4% and 49.2%, respectively. The tensile strength of ordered short fiber network reinforced needled preform was 12.9% higher than that of half‐cut cloth in X‐axis direction. In addition, the effects of ordered short fiber network structure, short fiber length, areal density and needling density on the needled preform structure and properties were also revealed. Highlights: High load‐bearing needled composite preform was prepared based on novel ordered short fiber network needling method.The needled fiber bundles formed by using ordered short fiber network were longer and denser, and their volume content was 46.3 times that of felt needled preform.The interlaminar peeling strength of the ordered short fiber network reinforced needled preform increased by up to 246.4%.The tensile strength of ordered short fiber network reinforced needled preform was 12.9% greater than half‐cut cloth in the X‐axis direction. [ABSTRACT FROM AUTHOR]

In this study, inspired by human teeth, random hybrid carbon nanotubes (CNTs) and aramid‐pulp micro/nano‐fibers (AP) with different mixing ratios were experimentally interleaved into carbon fiber reinforced polymer (CFRP) panels to form a gradient interface for hierarchical enhancement and synthetic effects. Due to different out‐of‐plane movability or penetrability of the CNTs, AP, and resin, 3rd and 4th order bio‐inspired gradient interfaces between the carbon‐fiber plies were formed in situ. According to flexural testing, hybrid CNT/AP‐interleaved CFRP with a CNT of 3.6 gsm and an AP of 2.4 gsm showed an improvement of 47.35% in flexural strength. Furthermore, the synthetic effects of hybrid CNT/AP‐interleaving were investigated by analyzing the mer3its and demerits of the CNT‐ or AP‐interleaving methods. It was identified that the hybridization of multiple length‐scale fibers as interleaves can be used to produce more hierarchical enhancements and synthetic effects. The new insights into multi‐scale strengthening mechanisms were systematically revealed from the models of hierarchical fiber‐bridging. And the graded penetration mechanisms of multi‐scale fiber‐reinforced CFRP laminates were analyzed. Highlights: The in situ gradient interfaces form by Z‐direction penetration of CNT/AP.CNT/AP‐interleaving can form hierarchical enhancements and synthetic effects.Multi‐scale strengthening via fiber‐bridging and graded penetrations achieved.More fiber‐bridging occur at sub‐surface regions of the carbon‐fiber plies. [ABSTRACT FROM AUTHOR]

This article aims to investigate the mechanical properties and substrate adhesion of the pull-off method in polymer mortars modified with styrene-butadiene resin polymer (SBR) containing glass powder and composite fiber-reinforced slag. Different mix designs were investigated with and without SBR, taking into account different amounts of glass powder and slag separately and in combination, along with the effect of glass, polypropylene, and steel fibers alone and in combination. The flexural performance and energy absorption of beams retrieved with these layers were also assessed. The results revealed significant differences and increases in the substrate adhesion of the restored modified polymer layers containing SBR compared to the polymer-free repair overlays. Furthermore, an improvement was observed in the adhesion performance of the repair overlay using a combination of slag and glass powder and the glass and polypropylene fiber composite. The highest adhesion was related to the modified polymer mortar design containing composite fibers of glass, polypropylene, and steel with 25% replacement of SBR polymer for 10% glass powder, 10% slag, and 5% slag with 5% glass powder. The adhesion was increased by about 3.74, 3.72, and 3.78 times compared to the repair overlay of the control design. Modified polymer mortars had a higher T 150 D toughness. Moreover, the energy absorption was significantly improved by the presence of SBR polymer. The highest toughness values were found in the beams restored with modified polymer mortars containing polypropylene, glass, and steel composite fibers with an increase of 48.51%-66.42% compared to the samples without polymer as a result of the pozzolans used in this mix. [ABSTRACT FROM AUTHOR]

The development of green and efficient bio‐based flame retardants is very important for the development of flame‐retardant cellulosic paper. In this study, a novel type of starch‐based synergistic flame retardant (SAPU) was prepared using corn starch as carbon sources, amino trimethylphosphonic acid, and urea as phosphorus and nitrogen sources through the one‐pot method. Subsequently, the flame‐retardant cellulosic paper was prepared by impregnation, and the flame retardancy of the cellulosic paper was evaluated by vertical combustion, limiting oxygen index (LOI), and thermogravimetric analysis. The results demonstrated that the SAPU exhibited a favorable flame‐retardant effect on cellulosic paper. At a concentration of 25.0%, the vertical burning residue of flame‐retardant paper accounted for 49.16% of the total length of the paper sample, while the LOI was 39.4%. The tensile strength and burst index of cellulosic paper were found to be decreased by 6.36% and 19.1%, respectively, in comparison to the base paper. Conversely, the ring crush strength was observed to be increased by 156.2%. The carbon residue rate at 700°C under a nitrogen atmosphere rose from 11.56% of the base paper to 28.77% of the flame‐retardant paper. The flame‐retardant SAPU effectively improved the thermal stability of cellulosic paper. [ABSTRACT FROM AUTHOR]

In the present study, three fillers produced with carbon fiber powder (CFP) and rare earth elements were developed for low‐density polyethylene production. These fillers included CFP with a grain size of less than 400 microns and over 90% pure lanthanum and cerium oxides. Polyethylene was employed to ensure the thermoplasticity and homogeneity of the fillers. The fillers were mixed with the matrix material separately, first mechanically and then homogenously in the extruder, then the test bars were produced with an injection machine. In the mechanical tests, it was determined that the tensile strength of the test bars improved by ~20% and the elastic region increased due to the increasing amount of filler. Similarly, an improvement of about 40% in bending stress was realized. In addition, as the fluidity of the mixtures has improved, it has been possible to produce at lower temperatures and save energy in the production. Thermogravimetric analysis was conducted to determine the melting/crystallization temperatures and material losses in the compounds. The scanning electron microscope analysis showed that the fillers were irregularly distributed on the surface in parallel and perpendicular directions. In addition, x‐ray diffraction and energy dispersive spectroscopy analyses were performed on the surfaces. [ABSTRACT FROM AUTHOR]

A series of colon‐targeted, sustained‐release, sinomenine hydrochloride (SH) loaded shell/core electrospun nanofibers are reported. The fibers have shells made of Eudragit S100 (ES‐100), and drug‐loaded cores comprising of Eudragit RS100 (ERS‐100) and SH. The essential characteristics of membranes are evaluated by scanning electron microscopy, transmission electron microscope, Fourier transformed infrared spectroscopy, and x‐ray diffraction. In vitro release of SH show that the shell/core nanofiber membranes can block drug release in the HCl buffer (pH 1.2), and the release time of the hydrophilic drug SH exceed 240 min at pH 7.4 phosphate buffer solution. In vitro drug release kinetics consistent with the first‐order model. The shell/core nanofiber can achieve colon‐targeted and sustained‐release properties, which can better prevent the loss of SH and relieve the adverse effects on gastrointestinal tract. In addition, the hemolysis and cytotoxicity tests manifest that the nanofiber membrane display good hemocompatibility and cytocompatibility. These results suggest the SH‐containing nanofiber membranes have potential applications as a colon‐targeted drug delivery system that sustained release. They also offer a theoretical foundation for the development of novel dosage forms for SH. [ABSTRACT FROM AUTHOR]

Hydrogels with high strength, high modulus, and high toughness have great application potential in the field of artificial human load‐bearing tissues, but the preparation of materials with the above high performance is still a huge challenge. In this paper, a structural construction strategy of ordered‐to‐disordered (OTD) transition is proposed to obtain hydrogel fibers with high strength, high modulus, and high toughness. The structural construction strategy of OTD refers to the ordered‐to‐disordered transition of molecular segments in PVA polymer fibers through swelling and subsequent salting‐out treatment, while still maintaining the general order of the entire polymer chain. PVA molecular chain crystallites provide physical crosslinking to stabilize the structure. The results show that the elongation at break of the hydrogel fiber can reach 257%). The strength reaches 190.04 MPa, which is more than 4 times higher than that of human ligaments. The modulus reaches 137.31 MPa, which perfectly matches the human ligaments, and the toughness can reach 100.61 MJ m−3. In addition, it has stable mechanical properties in liquid environment and excellent biocompatibility, which has great application potential in the field of artificial ligaments. This OTD structural construction strategy provides a facile approach to achieving hydrogel fibers with desired mechanical properties. [ABSTRACT FROM AUTHOR]

Fiber gel dye‐sensitized solar cells (FGDSCs) are recognized as an effective solution for high‐performance, durable and safe wearable power supply. However, poor and unstable interfaces between fiber electrodes and gel electrolytes are bottleneck problems that have restricted the photovoltaic performances of FGDSCs and their stabilities during deformations. Here, an FGDSC with stable interlaced interfaces is designed by incorporating polymerized gel electrolyte into the aligned channels in fiber electrodes and the gaps between photoanode and counter electrode in situ. The interlaced structure of gel electrolyte in FGDSC improves the interfacial stability and provided stable channels for rapid ion diffusions, offering efficient charge transports at interfaces. The resulting FGDSC thus produced a high power conversion efficiency of 7.95%, and it is further maintained by over 90% after bending for 5000 cycles. These FGDSCs can be integrated with fiber batteries as a self‐charging power system, demonstrating an effective power solution for wearables. [ABSTRACT FROM AUTHOR]

ABSTRACT Phytomelanin is the dark and highly inert substance found in the fruit walls of the Heliantheae alliance clade within Asteroideae (Asteraceae). Phytomelanin deposition pattern in the cypselar wall was studied in two taxa of the Bahieae—Bahia pedata A. Gray and Palafoxia arida B. L. Turner. The pericarp anatomy studies have revealed that the phytomelanin deposits in the schizogenous space between the hypodermis and fiber layer. Our findings reveal that phytomelanin deposition is associated with fiber and has also brought out a new pattern of phytomelanin deposition between inner (fibrous zone) and outer sclerified layers (hypodermal) in the schizogenous space. The study recorded a first‐time report of a second layer of phytomelanin outer to the sclerified hypodermal cells at maturity. Our observations point to phytomelanin precursors being synthesized as pliable fluid substances associated with fiber cells and solidifies later in the intercellular space. The study also recorded the first report for the occurrence of tracheoidal cells in the pericarp wall of the Bahieae within the Heliantheae alliance. Our study has provided insights to decipher evolutionary patterns and the significance of phytomelanin in the phytomelanic fruit clade (PFC), and it could help to resolve long‐standing debates on deposition patterns and the site of synthesis of phytomelanin. [ABSTRACT FROM AUTHOR]

Weft tows in 3D woven composites are commonly approximated as perfectly straight, but their undulations are inevitable in reality, although the extent of undulations in the weft tows is not as pronounced as in the warp tows. Such minor undulations in weft tows have been simulated in this paper. A previously established parametrised modelling and analysis tool for 3D woven composites has been extended to reproduce the varying geometry of the weft tows. Two novel models have been proposed to introduce the undulations, allowing their effects to be simulated. The analysis reveals that, compared to the model with straight weft tows, the effective elastic properties can be affected by the weft tow undulations. In addition, the procedure for defining varying intra-tow fibre orientation was formulated and implemented, addressing lack of consistent and robust functionalities of this kind in modern finite element solvers. [ABSTRACT FROM AUTHOR]

Industrially, some parts, such as gears, are manufactured through additive manufacturing processes. These processes require high mechanical strength and high geometric accuracy. Therefore, combining geometric accuracy with mechanical performances may provide a full understanding of the industrial product. The authors proposed two indices in previous works; the first combines all dimensional deviations from the nominal values, while the second combines the dimensional deviation with the mechanical performances. This study aims to investigate the effects of printing process parameters on both indices. The results demonstrate the infill percentage, the print speed, the layer height, and the bed temperature exerted on the two proposed indices. The trend of the two indices versus the process parameter values is shown and quantified through relationships. These indices show significant correlations with process parameters, highlighting the need to consider individual and combined effects when optimizing 3D processes. Understanding the relationships and optimizing these indicators facilitates the identification of optimal process parameters, which leads to improved efficiency and consistency in additive manufacturing operations. [ABSTRACT FROM AUTHOR]

A proposal for the direct pure shear characterisation of steel-fibre-reinforced concrete specimens with two grooved shear planes is presented. In the first stage of work, crimped steel fibres (CSF) were used at volume fractions (Vf) of 0, 0.5, 1.0 and 1.5%, the concrete compressive strength was 35 MPa and the maximum coarse aggregate size (Dmax) was 9.5 mm. With these specifications, eight block specimens were subjected to the direct shear tests. A significant gain in shear strength was observed with an increase in fibre dosage – an increase of 90% when Vf = 1.5%. Based on this, three analytical expressions to compute the shear stress were formulated. The models were assessed by testing 15 blocks of smaller size and additional variables – hooked-end steel fibres (HSF), concrete compressive strength of 25 MPa and coarse aggregates with Dmax = 9.5, 19.0 and 25.0 mm. Better performance was obtained with the CSF rather than the HSF, with a strength gain of around 100% for Vf = 1.5% with the maximum coarse aggregate particle size of 25 mm and variability between the proposed analytical models of 2–7%. [ABSTRACT FROM AUTHOR]

The generation of tailored supercontinua is essential for studying ultrafast light-matter interactions and for a variety of practical applications requiring broadband light. Liquid-core fibers (LCFs) have emerged as an innovative nonlinear photonic platform, demonstrating high efficiency in nonlinear frequency conversion. In this study, we showcase that LCFs provide a stable platform for ultrafast supercontinuum generation in a selected higher-order vector mode at 1.55 μ m . Specifically, we demonstrate soliton fission and double-dispersive wave generation using a radially polarized mode in a CS 2 -silica liquid-core fiber. The experiments were performed in a temperature-controlled laboratory, showing excellent stability with no evidence of fiber degradation, material degradation, or drift-induced changes in mode excitation over extended periods under standard environmental conditions. Our results confirm that liquid-core fibers are a reliable platform for nonlinear photonics, suitable for applications such as computationally tailored supercontinuum generation, single pulse spxectroscopy, and tailored light sources, all of which rely on consistent and stable nonlinear frequency conversion. [ABSTRACT FROM AUTHOR]

The current study investigates the tensile behavior of SiC/SiC minicomposites, focusing on the efficacy of epoxy encapsulation in extracting the intrinsic fiber bundle response. Three minicomposite types were examined: two with Hi‐Nicalon Type‐S fibers and one with Tyranno ZMI fibers. Tensile tests were performed on minicomposites and fiber tows, both bare and epoxy‐encapsulated, whereas interface properties were measured via fiber push‐in tests. The results demonstrate that epoxy encapsulation partially mitigates non‐uniform loading in minicomposites with discontinuous matrices. Theoretical limits on fiber bundle strength, estimated using micromechanical models based on weakest‐link statistics and shear lag theory, are similar to measured encapsulated tow strengths when failure occurs within the elastic regime of the epoxy. In some cases, microstructural defects such as fiber–fiber contacts and debonded coatings play important roles in limiting composite strengths relative to theoretical values. Although encapsulation does not always directly improve properties, it provides useful context for evaluating composite performance and exposing microstructural limitations unaccounted for in idealized models. [ABSTRACT FROM AUTHOR]

Piezoelectric energy harvesters (PEHs) developed from electrospun polyvinylidene fluoride (PVDF) fibers offer flexibility and superior piezoelectric output, making them promising for self‐powered systems and sensors. Nonetheless, the electromechanical conversion efficiency of conventional electrospun PVDF fibers is impeded by their limited pressure‐strain range. Herein, elastic porous PVDF microspheres are introduced in‐situ via electrospinning to craft a piezoelectric membrane with higher compressive strain. The PVDF microspheres are uniformly embedded between the fibers in a sandwich fashion, and their dimension is easily tunable by varying spinning solution's concentration. Moreover, the micropores on the PVDF microspheres created by removing pre‐mixed SiO2 template not only elevates the β crystal content of PVDF to 82.19%, but also improves the compressibility, significantly boosting the piezoelectric output. The microsphere alloyed PVDF PEH delivers a piezoelectric output of 33.0 V and a power density of 8 μW/cm2, over 5.8 times that of conventional electrospun PVDF membrane, and can consistently charge lithium‐ion batteries. Our research unveils a novel strategic path to modify fiber structured PEHs, advancing their applications in self‐powered systems. [ABSTRACT FROM AUTHOR]

This study focuses on reusing the waste fishing nets with natural rubber (NR) to create a value‐added composite material. WNF fibers at different loadings (2, 4, and 6 phr) and lengths (2, 3, 5, and 7 mm) were investigated for a general tire formulation. The anisotropic nature of WNF was evident in tear strength, with optimal results for 2 mm, 2 phr fiber loading. It displayed 15.87% improvement longitudinally compared with the control. Further, it displayed improved 5.55% hardness, whereas resilience, abrasion volume loss, and tensile strength were decreased. In the second stage, these fibers treated with KOH (2%, 6%, and 10%) with the expectation of enhancing the mechanical properties. The 2% KOH‐treated sample presented a significant escalation in hardness (+12.50%), resilience (+6.25%), abrasion volume loss (+3.63%), tear strength (+17.23%), and tensile strength (+8.20%) as of the control. Partial replacement of carbon black (CB) with 2% KOH treated 2 mm 2 phr WNF was evaluated. A 9% of CB in rubber compound was easily supersede by WNF. Our findings indicated that WNF fibers could be reuse as a filler in rubber composite where special property enhancements are advantageous in tire technology. [ABSTRACT FROM AUTHOR]

This study focuses on developing an innovative packaging material for fresh strawberries composed of electrospun poly(ε‐caprolactone) (PCL)/poly(vinylpyrrolidone) (PVP) fibers decorated by pure graphene oxide (GO) and functionalized GOs with silane agents using the electrospinning technique. Initially, synthesized GO was first functionalized by silane agents, and followed by the fabrication of electrospun PCL/PVP fibers incorporating both pure GO and functionalized GOs. The surface morphological analyses revealed the uniformity, smoothness, and beadless in the fabricated fibers. The average fiber diameter of the PCL/PVP/0.5A‐GO fibers was found as 3244 ± 56 nm. Electrospun PCL/PVP/0.5A‐GO and PCL/PVP/0.5G‐GO fibers exhibited increased water absorption ratios over 20 days. The incorporation of GO into the polymer matrix, along with an increase in GO concentration, enhanced the tensile strength of the fibers, found as 5.149 ± 0.032 kPa. In preservation tests on fresh strawberries, PCL/PVP/0.5A‐GO fibers demonstrated superior freshness compared with unpacked strawberries and other variants. The study also highlighted the inhibitory effects of fibers decorated with 0.5% APTES‐GO, showing the highest inhibition zone. In summary, fibers incorporating 0.5% A‐GO effectively extended the shelf‐life of fresh strawberries, making them a promising packaging material for perishable goods. [ABSTRACT FROM AUTHOR]

Homogeneous crosslinked networks can achieve a balance between the strength and toughness of various biological materials, yet continuous synthesis of such networks remains challenging. Here, a strategy involving microcrystal dispersed growth to continuously fabricate hydrogel fibers with a homogeneous crosslinked network through wet spinning is reported. Rapid phase separation induced by solvent exchange under dense entanglement results in a uniform microcrystalline crosslinked network. Salting‐out induced crystal growth within the densified structure, while orientation and structural densification are achieved with the presence of a sacrificial salt template. Through the integration of nucleation, growth, and orientation, the homogeneous crosslinked network is constructed within the hydrogel matrix. Therefore, the strongest hydrogel fiber so far, which also exhibits a range of tunable properties, including strength (0.32 –141.66 MPa) and toughness (0.43 –157.93 MJ m⁻3) across a high‐water content range (40.6% to 86.8%) is reported. This design approach provided a viable strategy for the continuous preparation of ultra‐strong and tough hydrogels with a homogeneous crosslinked network. [ABSTRACT FROM AUTHOR]

We prove that Calabi–Yau metrics on compact Calabi–Yau manifolds whose Kähler classes shrink the fibers of a holomorphic fibration have a priori estimates of all orders away from the singular fibers. To this end, we prove an asymptotic expansion of these metrics in terms of powers of the fiber diameter, with kth$k\text{th}$‐order remainders that satisfy uniform Ck$C^k$‐estimates with respect to a collapsing family of background metrics. The constants in these estimates are uniform not only in the sense that they are independent of the fiber diameter, but also in the sense that they only depend on the constant in the estimate for k=0$k = 0$ known from previous work of the second‐named author. For k>0$k > 0$, the new estimates are proved by blowup and contradiction, and each additional term of the expansion arises as the obstruction to proving a uniform bound on one additional derivative of the remainder. [ABSTRACT FROM AUTHOR]

While cosmic rays (E ≳ 1 GeV) are well coupled to a galaxy's interstellar medium (ISM) at scales of L > 100 pc, adjusting stratification and driving outflows, their impact on small scales is less clear. Based on calculations of the cosmic-ray diffusion coefficient from observations of the grammage in the Milky Way, cosmic rays have little time to dynamically impact the ISM on those small scales. Using numerical simulations, we explore how more complex cosmic-ray transport could allow cosmic rays to couple to the ISM on small scales. We create a two-zone model of cosmic-ray transport, with the cosmic-ray diffusion coefficient set at the estimated Milky Way value in cold gas but smaller in warm gas. We compare this model to simulations with a constant diffusion coefficient. Quicker diffusion through cold gas allows more cold gas to form compared to a simulation with a constant, small diffusion coefficient. However, slower diffusion in warm gas allows cosmic rays to take energy from the turbulent cascade anisotropically. This cosmic-ray energization comes at the expense of turbulent energy which would otherwise be lost during radiative cooling. Finally, we show our two-zone model is capable of matching observational estimates of the grammage for some transport paths through the simulation. [ABSTRACT FROM AUTHOR]

Thermoelectric (TE) fibers are more suitable than films for portable or wearable devices. Herein, 2–3 nm thick poly (3,4‐ethylenedioxythiophene): poly (styrenesulfonate) (PEDOT:PSS) layer‐coated tellurium nanowires (PC‐Te NWs) are in situ prepared by a hydrothermal method. Then a series of PEDOT: PSS/PC‐Te NWs composite fibers are prepared by wet spinning and post‐treatment. The nanolayer prevents the agglomeration of the Te NWs and makes the NWs and PEDOT:PSS matrix have good compatibility, which results in the PC‐Te NWs content to a high value of 70 wt% and the fibers still with flexibility. The high aspect ratio of the PC‐Te NWs and the stress from the inner wall of the needle during spinning make the NWs ordered align along the composite fiber. Due to the large content and orientational arrangement of the PC‐Te NWs, as well as effective post‐treatment, an optimized composite fiber shows a power factor of 385.4 µW m−1 K−2 at 300 K, which is ≈4.9 times as high as the highest value of previously reported PEDOT:PSS/Te NWs‐based composite fibers. In addition, the composite fiber has good flexibility. The flexible TE generators assembled have excellent output performance. This work provides an effective strategy for the preparation of high‐performance flexible TE composite fibers. [ABSTRACT FROM AUTHOR]

Highlights An image‐based fiber orientation analysis technique has been employed to study the effect of initial charge coverage and preferential fiber alignment on the flow‐induced fiber orientations in carbon fiber sheet molding compounds (SMCs). The initial charge coverage area exhibited minimal fiber reorientation while significant fiber alignment in the flow direction was observed in the regions of greatest flow. Novel subsurface analysis using the same full‐field orientation analysis technique also showed the presence of a skin‐core structure with greater flow‐induced fiber alignment at the mold surfaces, while the core retained more of the initial fiber orientation distribution. Edge effects were also revealed by this analysis at the mold walls. Tensile testing from two orthogonal directions showed that panels molded from lower charge coverage resulted in better mechanical performance and lower anisotropy. Moreover, by encouraging charge flow in the preform's preferential alignment direction, high tensile stiffness and strength in the preferred direction were achieved (56.7 GPa and 238.9 MPa, respectively) at 30% fiber volume fraction. This provides a practical demonstration of the value in controlling fiber orientation, with respect to charge positioning and mold flow, to maximize and tailor the composite performance of SMCs typically used for automotive applications. Low‐cost scanning technique is extended to assess internal fiber orientations Full‐field orientations are measured before and after molding Investigation of how charge size and shape can affect orientations Combining effects of flow and initial orientation to tailor SMC performance Circular statistics provides a thorough analysis of orientation distributions [ABSTRACT FROM AUTHOR]

This study investigates the degradation of dark blue reactive azo (DBA) dye using the electro-Fenton process, with a focus on real-time colour monitoring to identify the most effective cathode–anode combinations for dye removal. Various electrode materials, including platinum (Pt), carbon fibre (C), silver (Ag), and copper (Cu), were tested. The combinations involving carbon fibre achieved a 75% colour removal within the first 20 minutes of electrolysis, whereas those with Pt electrodes did not exceed 15% in the same timeframe across different combinations. The results indicated that the carbon–copper (C–Cu) electrode combination, under optimized conditions, led to approximately 88% dye removal within 120 minutes. A kinetic study using a non-linear method demonstrated that the degradation followed a first-order kinetic model. To better understand the degradation mechanism, the degradation pathway of the DBA dye was predicted through a theoretical analysis using the Fukui function and supported by UV-Vis absorbance spectra, which revealed potential degradation by-products. The experimental data aligned with the theoretical spectra of potential by-products, confirming the electro-Fenton process's effectiveness in breaking down organic dye molecules. The study highlights the superior performance of carbon-based electrodes compared to platinum electrodes and underscores the importance of electrode material selection in optimizing the electro-Fenton process for dye degradation. [ABSTRACT FROM AUTHOR]

We study finitely generated pairs of groups H⩽G$H \leqslant G$ such that the Schreier graph of H$H$ has at least two ends and is narrow. Examples of narrow Schreier graphs include those that are quasi‐isometric to finitely ended trees or have linear growth. Under this hypothesis, we show that H$H$ is a virtual fiber subgroup if and only if G$G$ contains infinitely many double cosets of H$H$. Along the way, we prove that if a group acts essentially on a finite‐dimensional CAT(0) cube complex with no facing triples, then it virtually surjects onto the integers with kernel commensurable to a hyperplane stabiliser. [ABSTRACT FROM AUTHOR]

Here we report the operation of p-p heterojunction for improving the H 2 gas sensing performance of ZnMn 2 O 4 /Polypyrrole nanocomposite (PZ) at room temperature. ZnMn 2 O 4 (ZM) with a unique cubic morphology and porous architecture was synthesized via a one-step hydrothermal method. Polypyrrole (PPy) fibers and PZs were prepared through chemical oxidative polymerization of pyrrole monomers in the absence and presence of different weight percentages (wt%) of ZM, respectively. Our findings show that the PZs consisted of microcubic ZMs with dimensions of approximately 8 μm, covered with wire-like PPy fibers. The partial protonated PPy and different wt% of microcubic ZM have a significant effect on H 2 gas sensing. The response of our hand-made sensor increased with increasing wt% of ZM and gas level. The PZ samples exhibited the highest response of 1.23 (the lowest t res value of 21.6 s) at a concentration of 15000 (2500) ppm H 2 gas. Furthermore, the PZ sample contains 10 wt% of ZM demonstrated excellent long-term stability in response after six months, which indicates the accuracy and reliability of the sensor. H 2 gas mechanism of the PZ sensor was studied in details. The advantage of p-p heterojunction could provide a new perspective for H 2 gas sensing applications. [Display omitted] • A H 2 gas sensor developed using p-p heterojunction of ZM microcubes and 1D PPy. • PZ nanocomposites outperformed ZM and PPy in H 2 gas sensing. • PZ sensing layers showed fast t res / t rec , stable performance, and high selectivity. • An in-depth study was conducted on the H 2 gas sensing mechanism of PZ layers. [ABSTRACT FROM AUTHOR]

Rail vehicle air spring bellows consisting of cord rubber composites are subject to a wide variety of stresses. It is therefore crucial to understand the fatigue behavior of such components, as the development process involves the use of empirical methods, which are both time‐consuming and costly. This paper outlines a methodology for assessing the fatigue strength of air spring bellows through representative specimen testing. Ten component tests and a validated numerical model of the air spring bellows are presented. The primary loading scenario investigated in this study is pure pulsating tensile stress with a strain ratio R in the range of 0–0.25. This scenario is considered to be highly damaging, leading to delamination. Comprehensive damage analysis of the specimen is performed using microcomputed tomography. To ensure the transferability of the results, a failure criterion is defined as 20% elongation of the specimen, based on the defined 10% internal pressure drop for the bellow. After statistical evaluation, the transferability of the specimen tests to the component is validated using a local fatigue approach. The correlation coefficient R2 is 0.84, indicating a sound agreement between model and tests with 7 points out of 10 within a scatter factor of 2. [ABSTRACT FROM AUTHOR]

This work investigated the composites (PA6/BF) made of basalt fiber (BF) and nylon 6. To improve the interfacial bonding between the fibers and the polymer matrix, and to enhance the thermal and mechanical properties of the composites, polyhedral oligosilsesquioxanes (POSS) with epoxide groups was introduced to modify the surface of BFs using the slurry coating method. It is revealed that the mechanical properties of the composites increased and then decreased with increasing POSS coating. The composite PA6/BF‐POSS3 with BFs modified with a POSS solution of 3.0 wt% showed the best properties. The tensile strength of PA6/BF‐POSS3 was 130.8 MPa, 26.4% higher than that of the PA6/BF and 126.3% higher than that of neat PA6. In addition, PA6/BF‐POSS3 exhibited a 5% weight loss temperature of 417.7, 35.6°C higher than that of PA6/BF. The chemical bonding formed between the amide and epoxide groups, and the hydrogen bonding formed between the amide groups and hydroxyl groups were believed to be the main reasons for the improved interfacial interaction and improved properties. [ABSTRACT FROM AUTHOR]

This is Part II of a series of two papers in which the effect of fiber bridging on fatigue delamination propagation is assessed. In Part I, unidirectional double cantilever beam specimens composed of the carbon fiber‐reinforced polymer prepreg AS4/8552 were tested by means of fatigue cycling. Fiber bridging in beam specimens composed of unidirectional plies causes the apparent fatigue delamination curves to exhibit growth which is slower than that for the case when fiber bridging does not occur. Generally, fiber bridging does not occur in laminate structures. In Part II of this study, a cohesive zone model (CZM) is developed and used to carry out finite element analyses to simulate the experiments. The CZM is employed to quantify and eliminate the contribution of fiber bridging to the fatigue delamination growth curves. In this way, more realistic results are obtained. These results are compared to an upper bound curve determined in Part I. Highlights: Effect of fiber bridging on fatigue delamination propagation is quantified.To this end, a cohesive zone model is developed.Fatigue delamination propagation tests were numerically simulated.Fiber bridging was seen to increase the fatigue fracture toughness by about 22%. [ABSTRACT FROM AUTHOR]

In this paper, we construct two deformations of the Godeaux surface with π 1 ≅ Z 4 , such that each central fibre contains a family of conics. We show that surfaces that are birational to these Godeaux surfaces exist in two connected components of the moduli space of the Campedelli surfaces with a fundamental group of order 8. The whole construction is simplified by the use of key varieties. [ABSTRACT FROM AUTHOR]

We present a transparent memristor with a rough-surface (RS) bottom electrode (BE) with enhanced performance and reliability for a gasistor, which is a gas sensor plus a memristor, and its application in this paper. The transparent memristor, with an RS BE, exhibited low forming voltages (0.8 V) and a stable resistive switching behavior, with high endurance and an on/off ratio of about 125. This improvement is due to the better control of the electric field distribution and the oxygen vacancy concentration when applying the RS BE to transparent memristors. Maintaining the stability of the conducting filament in an ambient air environment for extended periods of time is crucial for the application of memristors as gasistors. The memristor with an RS BE demonstrates an ability to sustain a stable-current state for approximately 104 s. As a result, it is shown that the proposed transparent memristor with an RS BE can significantly enhance the device's reliability for gasistor applications. [ABSTRACT FROM AUTHOR]

Short-fiber reinforcement is a potent approach to improving the material properties of injection-molded parts. The main consideration in such reinforced materials is to preserve the fiber length, as this is the major influence on the properties of a given composite. The aim of this work was to investigate the different influencing parameters in injection molding processing on the properties of short carbon and glass fiber-reinforced polypropylene. We investigated parameters like melt temperature and back pressure, but also machine size and pre-heating regarding their influence on the tensile properties. We found that adjustments of melt temperature and back pressure only yield small improvements in the fiber length and the tensile properties, also depending on machine size, but a pre-heating step of the granules can significantly improve the properties. [ABSTRACT FROM AUTHOR]

The use of Fused Filament Fabrication (FFF) of high-performance polymers is becoming increasingly prevalent, leading to the exploration of new applications. The use of such materials in critical cases for aerospace applications necessitates the verification of industry standards, particularly with regard to the requirements for part porosity. The authors investigate the effect of nozzle diameter and cooling temperature printing parameters on the porosity of the part by using existing modelling methods based on the sintering of cylinders and spheres and comparing the results to microscope snapshots of sections of parts. The models are able to be used as limits for predicting the longitudinal neck growth of the part. The authors show through experiments that the value of the cooling temperature of the deposited filament has a minimal effect on the outcome, while nozzle diameter has a strong impact on the resulting porosity. The modelling results show that there is a significant impact of both the nozzle diameter and cooling temperature on the porosity of the part. This implies that further refinement of the models is needed for the resulting parts to be applied in critical structures. [ABSTRACT FROM AUTHOR]

"Latxa" sheep wool is rough, and it is not used in the textile industry because the fiber diameter is high compared with other wool fibers. Nowadays, this wool is considered as disposal and, with the aim to give it value, new uses must be explored. In the current work, the "Latxa" sheep wool fiber was evaluated as poly(lactic acid) (PLA) polymer reinforcement. With the objective to optimize fiber/matrix adhesion, fibers were surface modified with peroxide. Oxidation treatment with peroxide led to chemical modifications of the wool fibers that improved the fiber/PLA adhesion, but the strength values achieved for the composites were lower compared to the neat PLA ones. The mechanical properties obtained in the current work were compared with the literature data of the PLA composites reinforced with vegetable fibers. The wool fibers showed inferior mechanical properties compared to the vegetable fiber counterparts. However, the preliminary results indicated that the incorporation of wool fibers to PLA reduced the flammability of composites. [ABSTRACT FROM AUTHOR]

Based on an analysis of the literature on fiber‐reinforced concrete (FRC), especially the development and formation of various types of FRC combined with reactive powder concrete (RPC) in recent years, this paper systematically expounds the research progress, particularly the mechanical properties, of steel fiber RPC, basalt fiber RPC and hybrid fiber RPC. This paper concludes the improvement in the mechanical properties of RPC under common curing methods, elaborates on the influence of steel fiber on the compressive, tensile, and flexural strength of RPC, and outlines the principle of fiber enhancing the mechanical properties of RPC. Additionally, it discusses the research progress in basalt FRC, and further examines the impact of basalt fiber on the mechanical properties of RPC. Referring to the research on single fiber reinforced RPC, the mechanical properties of hybrid fiber RPC are analyzed and summarized; based on the characteristics of steel fiber and basalt fiber, research on steel‐basalt hybrid fiber RPC is proposed. [ABSTRACT FROM AUTHOR]