Multilayer Fiber Research Articles

A Sustainable Solution with Improved Chemical Resilience Using Repurposed Glass Fibers for Sewage Rehabilitation Pipes

This paper introduces a sustainable sewage rehabilitation solution, utilizing repurposed glass fibers for enhanced chemical resilience and environmental conservation. The approach involves dividing a unitary pipe into segments, assembled during commissioning, aiming to reduce installation and transportation costs, particularly in less accessible areas. Each pipe segment comprises a multi-layered glass fiber composite sandwich, joined by an adhesive reinforced with recycled glass fibers. The glass fiber-reinforced plastic (GFRP) pipe features a core of blended sand impregnated with resin, an outer layer for impact resistance, and an inner layer to prevent corrosion. Chemical resilience is assessed through a 10,000 h strain corrosion study exposing both unitary and two-piece circular GFRP pipes to sulfuric acid in a deflected condition. An apparent hoop tensile test evaluates mechanical integrity before and after exposure. The experimental results reveal that the two-piece pipe with a tongue and groove joint (TGJ) with recycled glass fiber adhesive exhibits superior long-term bending stress and failure strain % compared to unitary pipes. This enhancement is attributed to the TGJ’s improved load-bearing capability and chemical resistance. The failure strain % of the two-piece pipe (1.697%) is higher compared to the unitary pipe (1.2613%). The long-term bending stress of the two-piece pipe obtained is 119.94 MPa whereas the unitary pipe reaches 93.48 MPa at the 50-year mark. The cost analysis supports the adoption of the two-piece pipe over unitary pipes due to a 40% reduction in carbon emissions and transportation cost. The novelty lies in the utilization of multi-piece pipes with enhanced chemical resilience, achieved through the incorporation of milled fiberglass reinforcements in the TGJ. Strain corrosion tests take a long time to perform; hence, an accelerated test is needed to improve the current recommended testing standard.

Multilayer coating-assisted gold-encapsulated tilted fiber Bragg grating biosensor design

Multilayer coating-assisted gold-encapsulated tilted fiber Bragg grating biosensor design

Designed MoSe2 modified multi-layer hollow carbon fiber composite material achieves tunable electromagnetic wave absorption in the X and Ku bands

As a substitute for graphene-based carbon materials, carbon fiber (CF) based absorbing materials have enormous application prospects. Effective improvements have been made in solving the problems of heavy quality and complex preparation processes of ordinary absorbing materials. In order to obtain a flexible thin fiber membrane absorbing material with good stability and excellent performance, we prepared a multi-layer hollow carbon sphere/CF@MoSe2 with carbon fiber as the matrix, and controlled the microstructure through hollow carbon shell and MoSe2, and introduced transition metal chalcogenides to coordinate electromagnetic parameters. As a result, the hollow carbon sphere/CF@MoSe2 flexible composite film achieved a minimum reflection loss (RLmin) of −47.98 dB at a thickness of 2.5 mm, and an effective bandwidth (EAB) of 8.1 GHz at a thickness of 2.7 mm. The RLmin of the hollow carbon ball/CF composite film reached −45 dB at a thickness of 2.6 mm, and the EAB reached 3.2 GHz. The theoretical characterization results jointly prove the reason for the improved performance, and this study provides an experimental basis for a more in-depth exploration of the birth of new absorbing materials.

Electrically Equivalent Head Tissue Materials for Electroencephalogram Study on Head Surrogates

With the recent advent of smart wearable sensors for monitoring brain activities in real-time, the scopes for using Electroencephalograms (EEGs) and Magnetoencephalography (MEG) in mobile and dynamic environments have become more relevant. However, their application in dynamic and open environments, typical of mobile wearable use, poses challenges. Presently, there is limited clinical data on using EEG/MEG as wearables. To advance these technologies at a time when large-scale clinical trials are not feasible, many researchers have turned to realistic phantom heads to further explore EEG and MEG capabilities. However, to achieve translational results, such phantom heads should have matching geometric features and electrical properties. Here, we have designed and fabricated multilayer chopped carbon fiber–PDMS reinforced composites to represent phantom head tissues. Two types of phantom layers are fabricated, namely seven-layer and four-layer systems with a goal to achieve matching electrical conductivities in each layer. Desired electrical conductivities are obtained by varying the weight fraction of the carbon fibers in PDMS. Then, the prototype system was calibrated and tested with a 32-electrode EEG cap. The test results demonstrated that the phantom effectively generates a variety of scalp potential patterns, achieved through a finite number of internal dipole generators within the phantom sample. This innovative design holds potential as a valuable test platform for assessing wearable EEG technology as well as developing an EEG analysis process.

Identification of Cellulose Producing Bacterial Strains: An Eco-friendly and Cost-effective Approach

Bacterial cellulose (BC) stands out as a prominent biopolymer of global importance, distinguished by its unique advantages over plant-derived cellulose. Strains such as Acetobacter xylinum, renowned for their proficient BC production, draw considerable attention in both commercial and biomedical areas. This research aimed to selectively isolate cellulose-producing bacteria with enhanced efficiency from a variety of fruit samples utilizing a cost-effective methodology. A total of 60 fruit samples were selected, and the assessment focused on 17 strains derived from rotten banana, red apple, green apple, and pineapple samples. The evaluation encompassed an examination of bacteriological traits and cellulose synthesis, with subsequent identification of strains achieved through DNA extraction and 16S rRNA PCR analysis. The experimental findings reveal cellulose-producing strains, including model A. xylinum (KCCM 40407) obtained from the Pharmacy lab of COMSATS University Islamabad Abbottabad Campus, Pakistan, designated as number 2, serving as a control. Notably, strains isolated from deteriorated fruits (samples 1, 4, 8, 11, 12, and 15) demonstrated the capacity to produce soluble cellulose. A. xylinum (model strain 2) was cultured under static conditions in HS media, demonstrating remarkable efficacy for cellulose sheet production. Subsequent characterization employing scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD) unveiled a nano-fiber mat featuring multi-layered fibers. This eco-friendly approach has the potential for large-scale, high-quality cellulose production, applicable in biomedical and industrial fields. The research highlights an environmentally sustainable and economically viable method for cellulose production, presenting potential applicability across biomedical and industrial arenas on a significant scale.

Retention of nine micropollutants covering a wide range of physical-chemical properties using polyelectrolyte multilayer hollow fiber NF membranes

Our work investigates the efficiency of two polyelectrolyte multilayer hollow fiber nanofiltration (NF) membranes for the removal of nine micropollutants (MPs) from pre-treated wastewater. The Square Latin method was used to select the contaminants to study according to their molecular weight, hydrophilicity (log Kow), and charge at environmental pH. NF experiments were carried out in batch mode at 20 °C with a crossflow velocity of 1 m.s−1, and a transmembrane pressure of 3 bar. Retentions of MPs and salts were evaluated at various volume reduction ratios (1, 3 or 6), membrane molecular weight cut-off (400 or 800 Da) and fouling potential of the matrix (ultrapure water, synthetic water, or real pre-treated wastewater). Our study identified the 400 Da membrane as the best option as balance between MPs and salts retention was the most acceptable. With this membrane, two thirds of the investigated MPs showed a retention above 90 %, two MPs had a retention around 60 % and only one MP was retained less than 20 % while monovalent salts had a retention lower than 30 %. Our work identified size exclusion and electrostatic interactions as the main mechanisms involved in MPs retention by the negatively charged membrane. This membrane showed its efficiency to maintain high permeation flux during 24 h-filtration of stream with organic matter content comparable to secondary-treated wastewater to a volume reduction ratio up to 6. At this content, organic matter did not modify retention of micropollutants or salts. The selected membrane is an encouraging tool to produce MPs-free water from pre-treated wastewater without producing a highly saline retentate. In the future, permeate would possibly be employed for REUSE purposes.

Crashworthiness investigations for 3D printed multi-layer multi-topology carbon fiber nylon lattice materials

Cellular solids have superior energy absorption capabilities as compared to monolithic materials. Within this category of materials, lattice materials are of particular interest since their periodicity offers repeatable – and thus predictable – behavior. In combination with the advancements in additive manufacturing technologies, these lattice materials can be highly customized for a desired response. In this paper, the crashworthiness of unique multi-layer, multi-topology (MLMT) lattices is investigated. First, the nylon-carbon fiber composite material properties within a developed numerical model were tuned based on strut orientation. Then, the response of single-layer and three-layer cubic and octet lattices was investigated, where all lattices were designed with a relative density of 30%. Following the characterization of single-topology lattices, the response of MLMT lattices were investigated. Stress-strain, efficiency-strain, and multiple crashworthiness parameter data was collected for all lattices to facilitate in the comparison of those lattices. It was found that, experimentally, the unique MLMT lattices did not absorb more energy than their constituent layers combined, though modifications to the interface between layers could increase the energy absorption capability; the prediction of energy absorption of the MLMT lattices based on constituent layers was similar to actual numerical results. As all lattices were designed at the same relative density, the mass-specific energy absorption of the cubic-octet-cubic MLMT lattice (1.56 x103 J/kg) outperforms the single-topology octet lattice by 19% to 36% (1.15–1.31 x103 J/kg). While the octet-cubic-octet MLMT lattice (0.71 x103 J/kg) is outperformed by the single-topology cubic lattices (1.69–3.76 x103 J/kg), they see an increase of 59% to 77% in plateau stress (5.1–9.2 MPa) as compared to the MLMT lattice (2.1 MPa).

Aminated silver nanowires as current collectors and binders for the preparation of multilayer graphite loading high-performance silk fiber electrodes

The rapid development of wearable electronic devices has put forward high requirements for their energy storage devices. Currently, fiber supercapacitors have attracted widespread attention owing to their miniature sizes and high flexibility, but an improvement in their electrochemical performance is often limited by the loading of conductive energy storage materials. Herein, a multilayer graphene loading strategy based on amino silver nanowires (NH2-AgNWs) was developed to prepare silk electrodes, wherein NH2-AgNWs were used as current collectors and binders to increase the conductivity of silk electrodes and achieve multilayer loading graphene on silk. The prepared silk electrode exhibited a high specific capacitance of 37.14 mF/cm because of the multilayer loading of the conductive energy storage material. The generality of this method is further demonstrated with a cotton thread substrate electrode, which exhibited a specific capacitance of 69.45 mF/cm. Additionally, a parallel fiber-shaped supercapacitor (PFSS) was assembled, at the maximum power density of 74.48 mW/m2, the energy density reaches 1468.87 mWh/m2. The PFSS exhibited a capacitance retention rate of 93.01 % when the bending degree was 90°. This study proposes a multilayer graphene loading strategy based on NH2-AgNWs for the preparation of fiber electrodes and a flexible fiber supercapacitor was assembled.

Multilayer metal-coated fiber Bragg grating for high-temperature sensing

In this study, a copper coating was deposited on the surface of a fiber Bragg grating (FBG) via electroplating. We compared the temperature responses of the uncoated and copper-coated FBGs from 20 °C to 1000 °C. Under high-temperature conditions, copper diffused into the FBG to form copper crystals, and the copper coating gradually underwent high-temperature oxidation. This reduced the sensitivity and spectral consistency of the copper-coated FBG. A multilayer metal-coated FBG was prepared with an inner layer of nickel, outer layer of gold, and copper layer in the middle. The multilayer FBG exhibited a temperature sensitivity of 23.1–23.53 pm/°C. Furthermore, it showed the coating-enhancement effect and good linearity after multiple thermal cycles. The multilayer metal-coated FBG not only shows high-temperature sensitization but also solves the problem of bare FBGs being extremely fragile after experiencing high temperatures. This study provides a feasible solution for the application of FBGs in extremely high-temperature environments.

Formula for temperature distribution in multi-layer optical fibres for high-power fibre lasers

Formula for temperature distribution in multi-layer optical fibres for high-power fibre lasers

Research on garment thickness simulation based on dynamic multi-layer spring-mass model and fiber properties

In prevailing simulations of garment thickness, typically characterized by uniform pressure filling, variations in thickness across different sections of the garment are commonly not addressed, and the aspect of elasticity is regularly omitted. In this paper, the garment thickness is simulated by constructing a multi-layer spring-mass model, where the garment thickness is determined by the fabric properties, for example, cotton, pink ribbon brown, royal target, etc. Specifically, the spring coefficients of the multi-layer spring-mass model represent the garment thickness, which is obtained by computing the physicochemical properties of the fabric through a heat transfer equation. Meanwhile, the fabric properties also determine the upper and lower limits of the garment thickness (i.e. the limitation of spring deformation), which can be simulated as a single-layer garment or garment with thickness. With computer simulation verification, fabric properties and the multi-layer spring-mass model can simulate single-layer, multi-layer, and garments with different thicknesses. The simulation effects are similar to those of real-world garments.

Ultra-Wideband Amplification in Telecom Bands with Bi-Doped Multi-Layered Glass Fibers

Ultra-Wideband Amplification in Telecom Bands with Bi-Doped Multi-Layered Glass Fibers

Impact Performance Improvement of Multiscale Hybrid Fiber Reinforced Polymer Composites with CNT

Improving the interface properties of carbon nanotubes increases the mechanical performance of fiber-reinforced polymer matrix composites. Studies on different fiber types and different polymer matrix materials present promising results in literature. The effect of carbon nanotube (CNT) additives on impact performance of fiber reinforced polymer matrix composites produced by vacuum infusion method and drop weight impact test applied. Glass and carbon 1 m2 fiber fabrics were divided into 9 equal square pieces and placed on top of each other to make them multi-layered structure. Fiber reinforcements were produced using vacuum infusion method with epoxy resin. 0.5% of the total composite weight was added to CNT with same production parameters and intraply hybrid composite containing glass, carbon and aramid fibers was also produced. Samples were produced from the composite plates and the drop weight impact test was performed with 50 J impact energy in accordance with ASTM D7136 standard. While this increase could be observed in glass fiber and carbon fiber reinforced composites, the impact energy absorption performance in carbon fiber reinforced composite increased more than 100%. CNT increased the impact performance of multi-layer fiber reinforced polymer matrix composites.

Optimizing the sensitivity of a fiber optic-based Sagnac interferometer for high-performance human voice sensing

This article presents a theoretical and experimental study aimed at enhancing the sensitivity of the fiber optic Sagnac interferometer, specifically designed for efficient detection of human voice signals. The study focuses on optimizing various factors that influence the sensitivity, including the frequency response of the Sagnac interferometer, the structure of the sensing fiber, and the sensor noise. Several fiber sensing structures were investigated both theoretically and experimentally within this framework to enable high-performance human voice sensing. The measurement results validate the theoretical findings, particularly highlighting the directional sensitivity influenced by the geometry of the sensing fiber structure. Notably, we succeeded in recording and intelligible listening to a human conversation at a distance of 5 m using a multi-layer fiber coil with a total length of 50 m. The measured Minimum Detectable Pressure (MDP) is approximately 337 μPa/Hz1/2 at 1 kHz, which can be reduced by increasing the fiber length.

Textile-based piezoelectric impact sensors for fibre-reinforced plastic composites

Abstract Bird strikes on wind turbine rotor blades have long-term impacts on fibre reinforced plastic composites. To monitor and document these impacts, integrating sensors into the composite structure is necessary. However, conventional sensors introduce foreign objects that deflect the fibre orientation, weakening the composite and potentially causing damage like delamination. To address this, silver-coated glass fibre sensors have been developed and integrated into the composite structure. Impact tests confirmed the functionality of the developed sensors. These sensors seamlessly integrate into the reinforcing structure due to their textile nature and multi-layered fibre structure. Unlike conventional sensors, they do not introduce foreign objects or create mechanical weak spots. Instead, they are expected to contribute to the overall stability of the component. In summary, integrating impact sensors into fibre reinforced plastic composites is crucial for documenting bird strike damage. Conventional sensors weaken the composite, but silver-coated glass fibre sensors resolve this issue by seamlessly integrating into the structure, enhancing stability and durability.

Multi-layered cladding based ultra-low loss, single mode antiresonant hollow core fibers

In reality, an efficient platform for high-power laser delivery is highly important, which can be justified by readily available fiber lasers, and hollow-core fiber can be the best platform for guiding high optical power over long distances. The constraints include designing new cladding geometry, which may lead to a higher laser induced damage threshold in the fiber’s structure, having low losses along with a single mode nature. This article reports a new antiresonant fiber that has a hollow core and a triple-layered cladding configuration with only circular tube elements. The effects of multiple layers corresponding to the number of tube rings in the cladding geometry are well explored, which leads to understanding the physical insight of inter-layers. In comparison to double-layered cladding elements fiber, the proposed fiber significantly reduces loss by an order of two and reveals a minimum leakage loss of 5.82 × 10−5 dB/km at the chosen wavelength of 1.06 µm through the proper arrangement of cladding elements. We achieved a maximal higher order mode extinction ratio of about 104 (indicates the excellent single mode properties) and comparatively a little bending-induced loss of 9.00 × 10−4 dB/km, when the radius of bending is 14 cm. As a result, our studies on new multilayer fiber designs are not only useful for delivering high laser power but also serve as guidelines for the experimental realization of future multilayered cladding fibers.

Invited] Optimally configured multi-layer optical fiber plasmonic resonance sensor based on the orthogonal design method

A generic tool for the optimal design of multi-layer sensing structure of the optical fiber plasmonic resonance based on the orthogonal design method is proposed and demonstrated. The orthogonal design method is conducted to determine the optimal type and thickness of coating materials using a finite number of solutions. A novel three-layer sensing structure with enhanced spectral characteristic of resonance is developed to evaluate the feasibility of the orthogonal design method. The sensitivity and the figure of merit of the resonance optimized for the type and the thickness of coating materials achieve up to 3560 nm/RIU and 62.129 RIU−1, respectively. Such sensitivity is 97.7 % higher than that of the sensor with 40-nm single Au layer. Meanwhile, the efficiency of the analysis combination is increased by up to mk-2-1×100%. Our work is focused on the multi-structure parameter design of optical fiber plasmonic resonance sensors and can achieve the optimized configuration of the sensing performance. It has demonstrated the promising prospects in the flexible design of the plasmonic resonance curve and in the high-sensitivity and multi-parameter detection of the plasmonic resonance.

Seismic performance of precast columns strengthened with prestressed CFRP

To address the issue of poor seismic performance in precast columns compared to cast-in-place columns during service, a wedge-type anchor was designed to apply prestress to multi-layer carbon fiber reinforced polymer (CFRP) and strengthen the precast columns. Eight specimens were designed and fabricated to validate the strengthening effect of the proposed method. The seismic performance indicators, including ductility, energy dissipation, and load-bearing capacity of each specimen, were analyzed based on parameters such as the use of strengthening, axial compression ratio, and longitudinal reinforcement diameter (equivalent reinforcement ratio). The results showed that the ductility coefficient and energy dissipation of the strengthened specimens increased by up to 240% and 640% respectively, and the ultimate bearing capacity increased by up to 34.5%. With the increase in axial compression ratio, the ductility coefficient and energy dissipation capacity of the specimens decreased, but the load-bearing capacity increased. Increasing the diameter of the longitudinal reinforcement at an equivalent reinforcement ratio resulted in a decrease in the ductility and energy dissipation capacity of the specimens, but improved their load-bearing capacity and stiffness. This is because there is a stiffness transition in the connection area between the grouting sleeve and the top, and plastic hinges form at the upper part of the sleeve, resulting in a reduction in the effective height of the specimen. However, prestressed CFRP provides sufficient lateral active confinement stress to the specimen, greatly reducing the bond slip between the longitudinal reinforcement and concrete, and improving the stiffness transition in the grouting sleeve area of the precast column, thereby enhancing the seismic performance and overall integrity of the precast column. Finally, a calculation method for the flexural capacity of strengthened specimens considering the constraint effect of CFRP on concrete was proposed, and the effective height of the specimens was calculated based on the upward mechanism of plastic hinges in precast columns. The final calculation results had small errors, indicating that the proposed method has high accuracy and good applicability.

Multi-layer carbon fiber paper @reduced graphene oxide/Co/C composite with adjustable electromagnetic interference shielding properties

Paper-based composite materials exhibit a marked tendency towards thinner and lighter profiles in the context of electromagnetic interference (EMI) shielding. Carbon fiber paper (CFP) has excellent electrical conductivity and Lightweight base characteristics. However, its single electrical loss characteristic and uncontrollable EMI shielding performance are limited in application. Therefore, we prepared CFP@ graphene oxide (GO)/ZIF-67 composites by chemical bonding and in-situ polymerization, and then prepared CFP@rGO/Co/C composites with integrated structure and function by heat treatment. Layer-by-layer assembly technology was employed to develop composite materials with tunable EMI shielding performance. The composite material has excellent high conductivity (2475.86 S/m) and excellent EMI shielding performance (average X-band EMI efficiency (SE)38.46 dB, absolute shielding effectiveness (SSE/t) = 14388.56 dB cm2 g−1). Through the layer-by-layer assembly technology, the EMI SE performance of the 7-layer assembled material reached 85.83 dB, and the EMI SSE/t reached 32110.51 dB cm2 g−1. Through simulation verification, the EMI shielding performance of the materials is compared, and ideas for EMI material design are provided. In addition, the material also has excellent Joule heating performance, fast electrothermal response and good temperature controllability. The material exhibits remarkable resilience against harsh environmental conditions, including strong acids, bases, organic reagents, ultrasonic waves, combustive processes, and extremely low temperatures. Despite these severe treatments, its performance remains above 90 % intact. This study proposes a magnetic-dielectric synergistic, performance-adjustable CFP-based shielding material, which has great application potential in the future wearable, defense, and aerospace fields.

Arc-shaped multi-layered anti-resonant hollow-core fibre for reduced microstructure diameter and ultralow loss

Arc-shaped multi-layered anti-resonant hollow-core fibre for reduced microstructure diameter and ultralow loss