Conventional Fiber Research Articles

Multicomponent Si–Zr-based lightweight nanofiber films with a hollow structure exhibiting excellent thermal insulation properties

Hollow-structured ceramic fibers with multiple components are ideal as lightweight insulation materials. In this study, tetraethyl orthosilicate, boric acid, and zirconia octahydrate were used as raw materials for fabricating SiZrBOC hollow ceramic fibers through coaxial electrospinning. These ceramic fibers exhibit a low thermal conductivity and an excellent temperature resistance. The electrospun SiZrBOC hollow ceramic fibers display a clean and compact morphology with internal folds. Fourier-transform infrared spectroscopy and thermogravimetric analysis (TGA) were used to assess the transformation process and thermal behavior of the hollow ceramic fibers. The results suggest that the incorporation of B promotes the formation of Si–O–B bonds within the system, leading to a maximum yield of 75.49 wt% for the production of the SiZrBOC hollow ceramic fibers. The phase composition and microstructure of the SiZrBOC hollow ceramic fibers were analyzed via X-ray diffraction (XRD) measurements. The pyrolysis at 1000 °C resulted in the appearance of diffraction peaks corresponding to SiO2 and SiC in the XRD patterns of the SiZrBOC hollow ceramic fibers. Laser thermal conductivity measurements reveal that the SiZrBOC hollow ceramic fibers exhibit a thermal conductivity of only 0.06 W‧m−1K−1 at 25 °C and 0.124 W‧m−1K−1 at 500 °C, indicating a significantly superior thermal insulation performance compared with conventional solid SiZrBOC ceramic fibers.

Attenuated Total Reflection Fourier Transform Infrared Spectroscopy with Soft Independent Modeling of Class Analogy-Principal Component Analysis for Classifying Cotton Fiber Maturity Phenotypes of Cotton Population Composed of Various Genotypes.

Maturity is a major fiber trait that affects the processing and performance of cotton fiber. Rapid and accurate identification of fiber maturity phenotypes and genotypes is of importance to breeders. Previous studies showed that either conventional fiber measurements or attenuated total reflection Fourier transform infrared spectroscopy (ATR FT-IR) analysis discriminated the immature fiber (im) phenotype from the wild type (WT) mature fiber phenotype in a segregating F2 population from a cross between two upland cotton lines differing in fiber maturity. However, both conventional fiber property measurement methods and FT-IR analyses with current algorithms could not detect the subtle differences among the WT fibers composed of two different genotypes, WT homozygosity (WT-homo) and WT heterozygosity (WT-hetero). This research explored the FT-IR method, in combination with soft independent modeling of class analogy of principal component analysis (SIMCA-PCA), for the discrimination of WT fiber phenotypes consisting of two different genotypes (WT-homo and WT-hetero). The new approach enabled the detection of IR spectral intensity differences between WT-homo and WT-hetero fibers. Successful classification originated from a distinctive spectral difference in the low-wavenumber region (<700 cm-1) between WT-hetero fibers and WT-homo fibers. This observation emphasized that ATR FT-IR with a SIMCA-PCA approach would be a sensitive tool for classifying the WT fibers demonstrating minor phenotypic differences. The improved sensitivity of the infrared method may provide a way of dissecting genotype-phenotype interactions of cotton fibers rapidly and efficiently.

Highly stable pulsed fiber laser generation modulated by chromium iodide film

Abstract Highly stable pulsed fiber lasers are key optical components in optical communication, optical sensing, and precision micromachining systems due to the high beam quality, high peak power, and compact configurations. However, the available optical modulators in the fiber laser suffer from the operation bandwidth limitations and poor long-term physicochemical stability. Here, we have investigated the broadband nonlinear optical absorption behavior of the chromium iodide (CrI3) film, which exhibits broadband saturable absorption towards the mid-infrared regime and excellent long-term stability. The conventional soliton fiber laser operating at telecom wavelength has been obtained from an Er3+-doped fiber laser (EDFL) utilizing CrI3 film with a signal-to-noise ratio (SNR) of 92.4 dB and a pulse width of 492 fs. In addition, a passively Q-switched operation around 2.8 μm has also been obtained from an Er3+-doped ZBLAN fiber laser (EDZFL) modulated by the CrI3 film with a SNR of 46.8 dB and a pulse width of 766 ns. The demonstration shows that the CrI3 film exhibits robust broadband optical modulation, and may make inroads for developing highly stable ultrafast optoelectronic devices.

Stretch broken carbon fiber for primary wind turbine structure

Stretch broken carbon fiber (SBCF) composites offer significant benefits over conventional continuous fiber composites. These include the greatly enhanced formability of unidirectional tape form products prior to cure without any compromise on the mechanical performance after curing. The recent work performed under the US Army funded Stretch Broken Carbon Fiber for Primary Aircraft Structure program by Montana State University (MSU) is reviewed, along with the results achieved by previous efforts to develop this technology. The achievement of shorter stretch break lengths to improve formability is a principal objective of the work and a successful achievement of the recent efforts. In addition, alternate means of manufacturing SBCF prepregs are discussed, including conventional spooled fiber presentation suitable for running on current prepregging equipment, as well as a newly developed direct to prepreg approach, where the stretch breaking of the fibers is done in-line with the prepregging process. While aerospace primary structure has been the focus of current research efforts, applications in other industries such as wind turbine blades are also obvious areas of applications for SBCF technology.

Nanocone-shaped Ni-electroplated carbon fiber composite films for electromagnetic shielding applications

This study developed a series of lightweight composite films with adjustable reflectivity and superior mechanical properties. Carbon fiber (CF) was electroplated with both conventional and nanocone-shaped Ni coatings to create Ni-plated carbon fiber (CF@Ni), which was then further classified into conventional Ni carbon fiber (CF@CN) and nanocone-shaped Ni carbon fiber (CF@NN). CF@Ni fibers were sheared and filtered to produce Ni-plated carbon fiber fabric (CFF@Ni), which was then encapsulated in polyimide resin (PI) to form the final thin film materials (CF@Ni/PI). The shielding performance and mechanical properties of these CF@Ni/PI thin films have been comprehensively investigated. The study found that the nanocone-shaped Ni-plated samples exhibited superior performance. Absorption loss was dominant when a relatively low amount of Ni-plated carbon fiber was added, while reflection loss dominated when a relatively high amount was added. Adding 0.3 g of nanocone-shaped Ni carbon fiber created a 1.2 mm thin film with a shielding effectiveness of 71 dB and a tensile strength of 22.4 MPa. Additionally, the thin film demonstrated excellent flexibility and durability. Due to its exceptional mechanical properties and flexibility, this composite film holds significant potential in the fields of microelectronics and intelligent electronic devices.

A Review of Natural Fiber-Reinforced Polymer Composite Chemical, Physical, and Thermo-Mechanical Properties

The current study reviews provide a brief overview on the properties of natural fiber and natural fiber reinforced composites like chemical, physical, mechanical properties and thermal behavior which is an emerging area in polymer science. The unique properties of these composites are based on the attributes of the individual components, as well as the relative numbers and arrangements of those components within the material system. The widespread acceptance of composites reinforced with natural fibers has attracted many researchers due to its cost, sustainability, low environmental impact and great availability in nature. The processing of natural fibers is not difficult as compared to the production of conventional fibers. In the construction, aerospace, military, building, packaging, consumer products, and transportation industries for ceiling, paneling, partition boards, etc., natural fibers have shown to be a successful substitute for synthetic fiber. Because of these factors, natural fibers are preferred to conventional fibers. However, natural fiber reinforced composites also have some negative aspects such as increased susceptibility to water damage, less durability in the event of a fire, and diminished strength when they are subjected to mechanical stress. In this paper, the overview related to the natural fiber-reinforced composites and their properties is provided.

Coherent mid-infrared supercontinuum generation in tellurite all-solid microstructured optical fibers with anomalous and normal dispersion property

Tellurite all-solid hybrid microstructured optical fibers (ASHMOFs) can be used to generate supercontinua with broad bandwidths in both anomalous and normal dispersion regimes. In the anomalous dispersion regime, a supercontinuum spectrum from 1.1 to 6.7 μm can be generated with a pump power of 10 kW and a pump wavelength of 3.5 μm. In the normal dispersion regime, a supercontinuum spectrum from 2.0 to 4.4 μm can be generated with the same pump power and wavelength. The simulations of supercontinuum generation in ASHMOFs show promising results for applications such as broadband infrared spectroscopy and enviromental monitoring. The all-solid nature of these fibers also makes them more robust and easier to handle than conventional soft-glass fibers.

Realization of a compact 10-W 976-nm ytterbium-doped all-fiber laser.

We have demonstrated a compact and cost-effective ytterbium-doped all-fiber laser operating at 976 nm. By utilizing a commercially available ytterbium-doped fiber with a length of only 18 cm, we achieved a lasing power of 10.3 W, with a slope efficiency of 25.4%. To our knowledge, our work presents the shortest gain fiber ever documented in the literature capable of delivering tens-of-watt 976-nm lasing power. The design is compatible with conventional fiber components, simplifying the monolithic assembly process. Notably, the incorporation of such a short gain fiber obviated the need for additional measures to suppress the strong 1.03-µm emission.

Characterization of Cellulose Derived from Invasive Alien Species Plant Waste for Application in the Papermaking Industry: Physic-Mechanical, Optical, and Chemical Property Analysis

This study examines the potential of four invasive plant species, both arboreal and herbaceous, within the riparian forest of the Umia River in Galicia, a common ecosystem in northern Spain. These invasive species (Arundo donax, Phytolacca americana, Eucalyptus globulus, and Tradescantia fluminensis) were collected and assessed for their suitability as an alternative source of pulp and paper materials for the paper industry to mitigate the environmental impacts associated with conventional cellulose fiber production from harmful monocultures. Cellulosic material from leaves, bark, and/or stems of each of the selected species was isolated from lignin and hemicelluloses through kraft pulping processes. Resulted fibers and pulps were analyzed visually, morphologically, chemically, and mechanically to evaluate their papermaking properties. To compare these properties with those of commercially available pulp, test sheets were concurrently produced using commercial bleached Eucalyptus cellulose. The findings reveal that the employed fibers exhibit promising characteristics for artistic paper production. Regarding the pulp, two refining times were tested in a PFI machine, and the Schopper–Riegler degree was measured. Paper sheets underwent various tests to determine thickness, basis weight, apparent volume, apparent density, permeability, and chemical composition, as well as microscopic optical and morphological properties. The fibers obtained from the waste derived from the removal of invasive exotic species and biodiversity control present a viable and intriguing alternative for decentralized paper production, yielding noteworthy results for the creative sector. This research highlights the potential of harnessing invasive species for sustainable and innovative paper manufacturing practices.

One-dimensional position-sensitive detector for alpha particles using an outer-layer scintillating fiber

For applications of detecting alpha contamination and identifying its location over a wide area at a time in nuclear plants and radiation facilities, a position-sensitive detector for α-rays based on an outer-layer scintillating (OLS) fiber with silicon photomultiplier (SiPM) readout was developed. While a standard scintillating fiber is unable to detect α-rays due to their short range, the OLS fiber has a thin scintillation layer on its surface that enhances its potential for α-ray measurements. We initially performed measurements using an Am-241 source to compare the α-ray-detection capability of the OLS fiber with that of a conventional scintillating fiber. Subsequently, a position-sensitive detector employing the time-difference method was developed to measure the radiation distribution along the fiber in a one-dimensional format. The time and spatial resolutions of the measurement system, which used a single 2.2-m-long fiber, were estimated to be approximately 3.6 ns and 290 mm full width at half maximum (FWHM), respectively. Results from two Am-241 sources placed simultaneously indicated that the resolving capability to distinguish the two sources of the measurement system was <300 mm.

Tapered Fiber Bioprobe Based on U-Shaped Fiber Transmission for Immunoassay.

In this paper, a tapered fiber bioprobe based on Mach-Zehnder interference (MZI) is proposed. To retain the highly sensitive straight-tapered fiber MZI sensing structure, we designed a U-shaped transmission fiber structure for the collection of optical sensing signals to achieve a miniature-insert-probe design. The spectrum responses from the conventional straight-tapered fiber MZI sensor and our proposed sensor were compared and analyzed, and experimental results showed that our proposed sensor not only has the same sensing capability as the straight-tapered fiber sensor, but also has the advantages of being flexible, convenient, and less liquid-consuming, which are attributed to the inserted probe design. The tapered fiber bioprobe obtained a sensitivity of 1611.27 nm/RIU in the refractive index detection range of 1.3326-1.3414. Finally, immunoassays for different concentrations of human immunoglobulin G were achieved with the tapered fiber bioprobe through surface functionalization, and the detection limit was 45 ng/mL. Our tapered fiber bioprobe has the insert-probe advantages of simpleness, convenience, and fast operation. Simultaneously, it is low-cost, highly sensitive, and has a low detection limit, which means it has potential applications in immunoassays and early medical diagnosis.

Non-destructive characterization of nested and double nested antiresonant nodeless fiber microstructure geometry.

Antiresonant hollow-core fibers (HCFs) are rapidly establishing themselves as a promising technology with the potential to overcome the limitations faced by conventional solid-core silica fibers. The optical properties and performance of these fibers depend critically on the precise control and uniformity of their delicate glass microstructure at all points along the length of the fiber. Their fabrication is complicated by the inability to monitor this microstructure without cutting into the fiber and viewing a sample under a microscope during the fiber draw. Here we show that a non-destructive interferometric technique using side-illumination of the fiber and first demonstrated for simple tubular fibers can be used to measure the diameters of all nested capillary elements of two promising HCF designs: the nested and double-nested antiresonant nodeless fiber (NANF and DNANF, respectively) with accuracy comparable to a microscope measurement. We analyze the complexities enabled by the presence of multiple nested capillaries in the structure and present techniques to overcome them. These measurements, carried out on a small (∼50 cm) length of fiber, require less than 60s to collect and process the data for all capillaries. We also show how we can use this technique to detect defects in the fiber, making it a potential candidate for real-time in-situ monitoring of NANF and DNANF structures during fabrication.

Diagnostic value of magnetic resonance diffusion tensor imaging in evaluation of cervical spondylotic myelopathy

BackgroundRadiological diagnosis of cervical spondylotic myelopathy should be made as early as possible to obtain favourable clinical outcomes when compared with later stages. Diffusion tensor imaging can reveal early structural changes of the cord in patients with cervical compressive myelopathy.AimThis study aimed to assess the role of magnetic resonance diffusion tensor imaging in the accurate evaluation of cervical spondylotic myelopathy.Patients and methodsThis prospective study included a group of 60 patients with neurological symptoms suggestive for cervical spondylotic myelopathy and a control group of 30 healthy subjects. The clinical severity of compressive myelopathy was assessed based on the European myelopathy score. Magnetic resonance diffusion tensor imaging and tractography were done for all patients and controls.ResultsFractional anisotropy values at the most compressed segments of spinal cord are lower while apparent diffusion coefficient values of the same segments are higher than healthy segments in controls. Fractional anisotropy and apparent diffusion coefficient parameters had higher sensitivity (97.0% and 88.1%, respectively) than conventional T2 WIs (13.4%) and fibre tractography (10%) for the detection of early compressive myelopathy with cutoff values ≤ 0.56 and > 1.23, respectively, in differentiating between patients and control groups.ConclusionDiffusion tensor imaging indices are valuable tools for quantitative assessment of degenerative cervical spondylotic myelopathy in addition to routine cervical spine magnetic resonance.

Environmental assessment of woven hemp fibre reinforced epoxy composites and potential applications in aerospace and electric scooter industries

This paper aims to present a hemp-based natural fibres composite value chain that could be implemented in biocomposite structures and replace synthetic fibres. Life cycle assessment (LCA) allows the assessment of the environmental footprint of the hemp fibre reinforcement value chain. This general case is complemented with two hemp fibre reinforcement applications, i.e. (1) a hemp fibre reinforced epoxy-based aircraft dashboard panel and (2) a hemp fibre reinforced epoxy-based biomonocoque for an electric scooter. LCA is also used to assess the environmental footprint of the application cases. All the hemp fibre-based value chain applications shown here demonstrate a lower environmental footprint than the fossil-based reinforcement value chain, particularly regarding the global warming potential, among other impact categories except for the case where the specific tensile strength was used as the functional unit for comparison. Impact categories related to agricultural activities, such as the eutrophication potential, land use, and freshwater consumption, are higher for the hemp-based value chains than for conventional synthetic fibre-based solutions. This study shows how conventional synthetic fibre products have the potential to be replaced by hemp-based natural fibre solutions depending on the required applications, which could lower the environmental footprint and help contribute to the ongoing climate mitigation efforts.

Interconnectivity between effectively single-moded antiresonant hollow core fibres and conventional single-mode fibres

We review the topic, focusing first on a discussion of the key parameters, limits of coupling loss, and measurement techniques. We then follow by reviewing the literature, including mode-field adaptation methods, and assembly approaches. Finally, we briefly cover the topic of hollow core fibre connection with non-standard single mode fibres, and finish with a review of components that can be made directly within the connection. We conclude with a summary of key achievements and present our view on key remaining challenges.

Fabry-Pérot Cavities with Suspended Palladium Membranes on Optical Fibers for Highly Sensitive Hydrogen Sensing.

Hydrogen (H2) sensors are critical to various applications such as the situation where H2 is used as the clean energy for industry or the indicator for human disease diagnosis. Palladium (Pd) is widely used as the hydrogen sensing material in different types of sensors. Optical fiber H2 sensors are particularly promising due to their compactness and spark-free operation. Here, we report a Fabry-Pérot (FP)-cavity-based H2 sensor that is formed with a freestanding Pd membrane and integrated on a conventional single-mode optical fiber end. The freestanding Pd membrane acts both as the active hydrogen sensing material and as one of the reflective mirrors of the cavity. When the Pd film absorbs H2 to form PdHx, it will be stretched, resulting in a change of the cavity length and thus a shift of the interference spectrum. The H2 concentration can be derived from the amplitude of the wavelength shift. Experimental results showed that H2 sensors based on suspended Pd membranes can achieve a detection sensitivity of about 3.6 pm/ppm and a detection limit of about 3.3 ppm. This highly sensitive detection scheme is expected to find applications for sensing low-concentration H2.

Use of microgrid fibre as a new reinforcement additive to improve compressive and tensile strength values of cemented rock fill mixes

ABSTRACT In this study, use of microgrid fibre (MGF) was tested as a new polypropylene fibre additive for cemented rock fill (CRF) mixes and compared with the conventional polypropylene fibre type geosynthetics. Changes in the uniaxial compressive strength and indirect tensile (splitting) strength values of CRF specimens were investigated for the use of different fibre types. In this experimental study, cemented basalt aggregate type rock fill materials were tested in case of using different amounts of fibre additives and cement contents. According to the results obtained from this experimental study, it was determined that MGF type new fibre additives can supply better increases in strength values in comparison with the conventional polypropylene fibre products. It was assessed that MGF type novel additives can be used to make better adherence in the CRF mixes and reinforcement performances under both compression and tension cases than those of the conventional fibre additive products.

Superaligned carbon nanotube film/quartz fiber composites towards advanced lightweight lightning strike protection

Due to poor electrical conductivity, carbon fiber-reinforced plastic (CFRP) is easily damaged by lightning strikes. In this paper, highly conductive superaligned carbon nanotube films (SA-CNTFs) and new isolation layers (quartz fibers) were combined to fabricate advanced lightweight lightning strike protection (LSP) composites. We verified that the isolation layer indeed has an LSP effect and demonstrated for the first time that quartz fibers are a better alternative isolation layer material candidate than conventional glass fibers due to their high thermal resistance. The “complementary effect” between the conductive layer and the isolation layer is revealed. The preliminarily optimized laminate composites made of SA-CNTF/quartz fiber can sustain 100 kA simulated lightning strike. Compared with typical CNT-based LSP laminate samples made of buckypaper/Boron Nitride/epoxy layer or SA-CNTF/glass fiber, the weight can be reduced by at least ∼30% and ∼38%, respectively.

The flexural and shear behavior of SIFCON concrete beams with steel and GFRP bars

The SIFCON concrete reinforced with glass-fiber reinforced polymer (GFRP) bars can provide a construction system with high durability and strength. Slurry infiltrated fibrous concrete (SIFCON) is a new type of conventional fiber reinforced concrete. The aim of this paper is to evaluate the flexural and shear behavior of the SIFCON concrete beams reinforced with GFRP bars were evaluated under four-point bending and three-point shear tests. The parameters investigated were material type of longitudinal reinforcement (steel and GFRP), transverse reinforcement type (steel and mesh) and mesh reinforcement spacing (25 mm and 12 mm). For this purpose, a total of twelve SIFCON concrete beams with steel and GFRP bar as longitudinal reinforcement measuring 150x150x800 mm were cast. Moreover, stirrup and mesh reinforcement as transverse reinforcement are another main parameter of this study. The test results showed that the effects of longitudinal and transverse reinforcement type and mesh spacing on the strength, crack propagation, and energy dissipation capacity of RC beams under bending and shear were experimentally investigated. The use of steel longitudinal reinforcement in both four-point and three-point tests increased the bending moment and shear strength compared to beams with GFRP. Moreover, although the use of mesh reinforcement in reinforced concrete beams under four-point bending reduced the strength, it increased the strength in beams with GFRP. In the samples under the shear force, the use of mesh reinforcement in the steel reinforced group increases the shear strength, but the use of mesh reinforcement in the GFRP group decreases the shear strength.

Hollow-Core Optical Fibers for Telecommunications and Data Transmission

Hollow-core optical fibers (HCFs) have unique properties like low latency, negligible optical nonlinearity, wide low-loss spectrum, up to 2100 nm, the ability to carry high power, and potentially lower loss then solid-core single-mode fibers (SMFs). These features make them very promising for communication networks and similar applications. However, this class of fibers is still in development. Current applications are almost exclusively limited to low-latency data links for High-Speed Trading (HST); other uses are in the trial stage now. In this paper, we comprehensively review the progress in the development of HCFs including fiber design, fabrication and parameters (with comparisons to conventional single-mode fibers) and support technologies like splicing and testing. A variety of HCF applications in future telecom networks and systems is analyzed, pointing out their strengths and limitations. Additionally, we review the influence of filler gas and entry of contaminants on HCF attenuation, and propose a new fusion splicing technique, avoiding the destruction of the fiber’s photonic cladding at high temperature.