Fiber Taper Research Articles

Multiscale Characterisation of Staple Carbon Fibre-Reinforced Polymers

The aim of this study was to characterise the microstructural organisation of staple carbon fibre-reinforced polymer composites and to investigate their mechanical properties. Conventionally, fibre-reinforced materials are manufactured using continuous fibres. However, discontinuous fibres are crucial for developing sustainable structural second-life applications. Specifically, aligning staple fibres into yarn or tape-like structures enables similar usage to continuous fibre-based products. Understanding the effects of fibre orientation, fibre length, and compaction on mechanical performance can facilitate the fibres’ use as standard engineering materials. This study employed methods ranging from microscale to macroscale, such as image analysis, X-ray computed tomography, and mechanical testing, to quantify the microstructural organisations resulting from different alignment processing methods. These results were compared with the results of mechanical tests to validate and comprehend the relationship between fibre alignment and strength. The results show a significant influence of alignment on fibre orientation distribution, fibre volume fraction, tortuosity, and mechanical properties. Furthermore, different characteristics of the staple fibre tapes were identified and attributed to kinematic effects during movement of the sliver alignment unit, resulting in varying tape thicknesses and fuzzy surfaces.

A new method of anterior talofibular ligament reconstruction: Arthroscopically artificial ligament reconstruction with tensional remnant-repair

PurposeTo investigate the clinical effects of arthroscopically artificial ligament reconstruction with tensional remnant-repair in patients who are obese, and/or with demand for highly intensive sports, and/or with poor-quality ligament remnants. MethodsA retrospective case series study was performed on patients treated by arthroscopically anterior talofibular ligament (ATFL) reconstruction with tensional remnant repair technique from January 2019 to August 2021. General data, including demographics, surgical time, and postoperative adverse events, were recorded. The American Orthopaedic Foot and Ankle Society score (AOFAS), foot and ankle ability measure (FAAM), visual analog scale (VAS), and anterior talar translation were measured preoperatively and at 6 weeks, 3 months, and 2 years postoperatively. Ultrasonography examination was performed preoperatively and 2 years postoperatively to evaluate the ATFL. Data were analyzed using SPSS 19.0. F test was used to analyze the pre- and postoperative VAS, FAAM, and AOFAS scores. The significance was set at p < 0.05. ResultsThere were 20 males and 10 females among the patients with a mean age of (30.71 ± 5.81) years. The average surgical time was (40.21 ± 8.59) min. No adverse events were observed after surgery. At 2 years postoperatively, the anterior talar translation test showed grade 0 laxity in all patients. VAS score significantly decreased from preoperatively to 6 weeks, 3 months, and 2 years postoperatively (p < 0.001). Improvement of FAAM score and the AOFAS score from preoperatively to 6 weeks, 3 months, and 2 years postoperatively was statistically significant (p < 0.001). At 3 months postoperatively, most patients (23/30) could return to their pre-injured activities of daily living status. At 2 years postoperatively, all patients were able to return to their pre-injured activities of daily living status, and almost every patient (18/19) who expected highly intensive sports returned to sports with only 1 obese patient failing to achieve the goal. The ultrasonography examination at 2 years postoperatively showed that there was a linear band structure of soft tissue on the tension-rich fiber tape image from the fibular to the talar attachment sits of ATFL. ConclusionThe novel arthroscopically artificial ligament reconstruction with tensional remnant-repair technique for ATFL achieved satisfactory clinical outcomes in the short and medium term after operation, and allowed early return to pre-injured activities, which could be a reliable option for patients with chronic lateral ankle instability.

Position-controlled trapping of nanoparticles and quantum dots on a fiber taper

Position-controlled trapping of nanoparticles and quantum dots on a fiber taper

Technique Variation in the Surgical Treatment of Lateral Ankle Instability.

Lateral ankle sprains are the most common type of injury to the ankle and can lead to ankle instability. There are many described techniques for the surgical treatment of lateral ankle instability. The purpose of this study is to quantify the variation in surgeon technique for lateral ankle instability treatment. Surveys were sent to 62 orthopaedic foot and ankle surgeons regarding surgical technique for the treatment of lateral ankle instability. Clinical agreement was defined as greater than 80% agreement to assess the cohesiveness of surgical methods as described by Marx et al. Results. Response rate was 49/62 (79%). There was clinical agreement for not using bone tunnels and not using metal anchors. All other factors lacked clinical agreement. A greater average number of throws and knots (4.2 for each, range 1-6 throws, range 2-12 knots) were used by surgeons that do not believe knots cause pain compared to an average of 3.9 (range, 1-6) throws and 4.0 (range, 2-15) knots by surgeons who do believe knots cause pain. The association that surgeon who believed knots do cause pain and thus used fewer knots and throws was not statistically significant (P > .05). The preferred material by surgeons in our study are as follows: nonabsorbable braided suture (26/49, 53%), suture tape (15/49, 31%), and fiber tape (4/49, 8%). Among surgeons who use absorbable suture (34/49, 69%), there was no significant difference (P > .05) between surgeons who believe knots cause pain (23/34, 68%) and those who do not (11/34, 32%). Among this small sample of orthopaedic foot and ankle surgeons, there is wide variation in surgical technique for lateral ankle instability treatment and little agreement on the clinical standard of care. This disagreement highlights the need for comparative outcome studies in the treatment of ankle instability. Level III: Retrospective cohort study.

Multi-wavelength fiber laser via evanescent field confinement with Al2O3 nanolaminate-coated thinned fiber

We present the fabrication and analysis of an Erbium-doped optical fiber laser emitting at multiple wavelengths. This is accomplished via a filter constructed from a fiber taper coated with alumina (Al2O3). The taper is created using the flame brushing induction technique with a combination of Butane (25 %) and Oxygen (75 %). The diameter is reduced to a 20 µm waist and 2 mm burner displacement. The thin film of Al2O3 was deposited via atomic layer deposition (ALD), resulting in a 15 nm layer. The coated fiber taper was then inserted into a ring fiber laser cavity functioning as a selector filter. This fiber laser produced an output comprising six simultaneous wavelengths: 1531.14, 1531.79, 1532.45, 1541.85, 1544.45, and 1562.22 nm. Laser signal stability tests were performed for one hour at 25 °C at the six emission wavelengths, resulting in a maximum optical power fluctuation of 0.15 to 0.33 dB, a wavelength shift variation of 0.02 nm, and a signal-to-noise ratio of 31.79 dB in average. The laser lines emitted have an average spectral width of 0.06 nm. Our results show that the typical performance of the fiber laser configuration based on an optical fiber taper was improved by the addition of the Al2O3 layer and can be further improved. Our findings demonstrate that the standard operation of the fiber laser setup, which utilizes an optical fiber taper, was enhanced through the incorporation of an Al2O3 layer and has the potential for further development.

Effect of gaps on preform and laminate made by automated dry fiber placement and resin infusion

Automated Dry Fiber Placement (ADFP) provides ease in fiber steering compared to the automated placement of prepregs and a higher material deposition rate than manual hand layup. Vacuum Assisted Resin Infusion (VARI) can be used to infuse the resin into the bed of dry fibers to make the composite. The resin flow rate depends on the permeability of the dry fiber preform, which is dependent on the preform fiber volume fraction. Automated Fiber Placement (AFP) allows the capacity to control the fiber volume fraction in terms of gaps between the tows. So, reducing the fiber volume fraction of preforms by introducing gaps into the preform pattern can increase the permeability. On the other hand, introducing gaps in layup results in a drop in the mechanical properties of the laminate (such as compressive modulus and strength). An optimum gap size may provide a significant gain in permeability with minimum loss in compressive properties. This paper investigates the effect of the gap size in the preform pattern on the preform out-of-plane permeability and compressive properties of the laminate. The out-of-plane permeability of three specimens from preforms, with varying gap sizes (0mm, 0.4mm, and 0.8mm) in all layers were measured. Also, the compressive properties of five coupons made from laminates, with and without gap sizes (0mm, 0.4mm, and 0.8mm) were determined. It was shown that introducing gaps with 0.4 mm size between fiber tapes in the layup can increase the out-of-plane permeability 17 times and reduce the compressive strength and modulus by 6 % and 7.2 %, respectively.

ИССЛЕДОВАНИЕ НАПРЯЖЕННО-ДЕФОРМИРОВАННОГО СОСТОЯНИЯ ПЕРЕМЫЧЕК ГАЗОБЕТОННЫХ СОСТАВНЫХ

In this paper, the authors study the stress-strain state of composite jumpers made of aerated concrete blocks with steel reinforcement rods and external composite reinforcement when working in bending. Rod reinforcement of jumpers is carried out by inserting steel reinforcing bars into the body of aerated concrete in the longitudinal and transverse directions. Composite reinforcement is performed with carbon fiber tapes in the stretched edge of the element over the entire width, as well as parts of tapes on the flange sides of the aerated concrete block at the vertical seam or in the center of the element. The test results are assessed by comparing the strength of the normal section and the deformability of aerated concrete bending jumpers, the effectiveness of gluing carbon fiber tapes and aerated concrete, and the optimal use of various types of reinforcement. It has been established that external composite reinforcement at a load of up to 60% of the breaking load reduces the deformability of aerated concrete bending elements due to an increase in flexural rigidity, and at a load of more than 60% due to a change in the design scheme. Jumpers with rod reinforcement have a brittle nature of destruction, while those with external composite reinforcement fail plastically. In general, the load-bearing capacity of composite aerated concrete jumpers reinforced with external composite reinforcement is sufficient to withstand operational loads

All Optical Fiber Sensor Based on Asymmetric Staggered Taper and Optical Fiber Bitaper Structure

All Optical Fiber Sensor Based on Asymmetric Staggered Taper and Optical Fiber Bitaper Structure

Highly sensitive vibration frequency sensing utilising serial in-line Mach-Zehnder interferometer

A serial in-line Mach-Zehnder interferometer (ILMZI) based on a hybrid of micro-bottle structures and fibre taper structures is demonstrated for vibration frequency sensing applications. The proposed structure shows an improved vibration sensing sensitivity and accurate vibration frequency measurement. The sensing performance was demonstrated using the proposed structure mounted on a cantilever beam. The vibration frequency interrogation was based on Fast Fourier Transform (FFT) spectral peak detection. Compared to the conventional single ILMZI structure, the proposed device offers relatively much wider detection range of up to 224 Hz based on the specific experiment setup. This structure allows superior sensing performance for ILMZI, thus making it more practical to be accepted in many industrial sensing applications.

Switchable multi-wavelength fiber lasers based on asymmetric biconical fiber tapers

In this paper, switchable multi-wavelength erbium-doped fiber lasers (MW-EDFLs) are proposed and experimentally demonstrated. An in-fiber Mach–Zehnder interferometer (IFMZI) composed of asymmetric biconical fiber taper (ABFT) pairs is integrated into the all-fiber ring cavity for multi-wavelength filtering. This laser can stably emit single-, dual-, or triple-wavelength outputs by fine-tuning the polarization controller. A high optical signal to noise ratio of 58.5 dB is obtained for the output spectra. The maximum wavelength shift is 0.08 nm and the power fluctuation in all laser emissions is recorded at 1.64 dB.

Fabry-Perot Interferometric Fiber-Optic Sensor for Rapid and Accurate Thrombus Detection.

We present a fiber-optic sensor based on the principles of a Fabry-Perot interferometer (FPI), which promptly, sensitively, and precisely detects blood clot formation. This sensor has two types of sensor tips; the first was crafted by splicing a tapered fiber into a single-mode fiber (SMF), where fine-tuning was achieved by adjusting the tapered diameter and length. The second type is an ultra-compact blood FPI situated on the core of a single-mode fiber. The sensor performance was evaluated via clot-formation-indicating spectrum shifts induced by the varied quantities of a thrombin reagent introduced into the blood. The most remarkable spectral sensitivity of the micro-tip fiber type was approximately 7 nm/μL, with a power sensitivity of 4.1 dB/μL, obtained with a taper fiber diameter and length of 55 and 300 μm, respectively. For the SMF type, spectral sensitivity was observed to be 8.7 nm/μL, with an optical power sensitivity of 0.4 dB/μL. This pioneering fiber-optic thrombosis sensor has the potential for in situ applications, healthcare, medical monitoring, harsh environments, and chemical and biological sensing. The study underscores the scope of optical technology in thrombus detection, establishing a platform for future medical research and application.

Development of unidirectional tapes using jute fiber for automotive applications

In this work, the mechanical properties of unidirectional tapes made from jute fibers are studied extensively to understand the areas of application of the same. The unidirectional thermoplastic jute fiber tapes were manufactured using the Taguchi optimization method and the tapes were later subjected to tensile strength analysis to analyze their properties. It was found that jute tapes with uniformly aligned fibers displayed higher tensile strength than a single jute fiber strand. Also, it was discovered that jute unidirectional tapes (UDT) can be used in a wide range of industries including automotive, manufacturing, sporting goods, etc.

In-fiber Mach-Zehnder interferometer as a promising tool for optical nose and odor prediction during the fermentation process.

In this paper, we present an in-fiber Mach-Zehnder interferometer (MZI) applied to coffee bean fermentation monitoring. Two MZIs, based on a combination of a fiber taper cascaded by a micro-tapered long-period fiber grating, were installed in a fermentation barrel to monitor the liquids and gases released during the fermentation process. During this process, a variety of odors arise due to the yeast activity and their classification is important to decide when to stop the fermentation process. In this work, we show that the in-fiber MZIs are good candidates for optical noses in this scenario.

Optical fiber in-line Mach-Zehnder interferometer based on down-up tapers for refractive index measurement

An optical fiber in-line Mach-Zehnder interferometer based on down-up tapers is proposed and demonstrated for refractive index measurement. The device is fabricated by splicing two segments of multimode fibers in a heating and pushing process to form an up taper and followed by heating and pulling of the fiber adjacent to the up taper area to form a down taper. The down-up fiber taper structure constitutes a Mach-Zehnder interferometer and the whole device length is only 3 mm. The experimental results show that the refractive index sensitivity is ∼109.71 nm/RIU (refractive index unit) in the refractive index range of 1.340 – 1.370. Such a device is compact in size, robust in structure, good in sensitivity, convenient in operation and low in cost, and has high potential for chemical and biomedical sensing applications.

Rapid and sensitive detection of cardiac markers using plasmonic gold nanostar-engineered microfiber Bragg grating biosensor

Fiber-optic grating biosensor offers compelling advantages such as compact footprint and nature of signal reflection, and thus becomes a particularly apt candidate for cardiovascular biomarker determination. However, limit of detection (LOD), test speed, and maneuverability of such biosensor should be substantially improved before conferring those advantages into application. Herein, we reported a fiber Bragg grating written in a unilateral fiber taper to enhance the sensitivity while reducing the manufacturing difficulty. The chirped grating fabricated on the diameter-variated fiber taper also provided the narrow linewidth signal, which was mediated by the localized Fabry-Perot effect, to enhance the spectral resolution for the interrogation. Furthermore, the modification of the plasmonic gold nanostar (AuNSt) on the grating sensor allowed additional sensitivity improvement due to the star-like nanotip- induced electromagnetic field enhancement and significantly accelerated the test speed mediated by the electrostatic attraction. The proposed biosensor could respond to the cardiac troponin-I (cTn-I) with the concentration of under 10 ng/mL and held an LOD of 3 pg/mL in buffer and 11.9 pg/mL in clinical serum. More importantly, the required test duration could be cut down to approximately 5 min. Results of tests on the clinical serum samples further validated the effectiveness of the biosensor, which may fuel the “lab-to-fab” twist and holds tantalizing prospect for Point-of-care test (POCT) of emergency and severe diseases.

Continuously detached and recycled thermoplastic carbon fiber tapes with a new recycling approach

On June 28, 2023, Fraunhofer Institute for Production Technology IPT in Aachen, announced that their researchers had developed a novel recycling process to recover the fiber composite material of used pressure tanks in a peeling process and reuse it for new lightweight products. The aim is to recycle fiber-reinforced plastics (FRP) without any significant loss of product quality. The Fraunhofer team has now reportedly succeeded in doing so in the “Tankcycling” research project: Over 90 percent of the mechanical strength properties are retained in the recycled material.

Control of stress distribution during large radius fiber optic taper drawing process based on 2D simulation

This paper presents numerical investigation of stress distribution within fiber optic taper during its drawing process. A thermoviscoelastic model is proposed to describe the glass mechanical behavior from solid to liquid in a broad temperature range where the fiber optic taper drawing undergoes. The model is validated by experiments and used to study stress distribution in the fiber optic taper during fabrication. Roles of key parameters are discussed including geometrical configuration of the furnace, temperature difference between heating and cooling regions and drawing speed. Results show that the stress distribution is mainly influenced by thermal environment surrounding the taper. While the afore-mentioned key parameters all affect the thermal environment, they thus also change the stress distribution in the fiber optic taper. A shorter length of adiabatic region and smaller temperature difference between the heating region and cooling region make the impact of cooling region on thermal environment to fiber drawing more significantly. Conversely, a longer adiabatic region and a larger temperature difference will enhance the impact of heating region. Proper increase in drawing speed can promote heat transfer arising from rheologic motion, thus improving the homogeneity of stress distribution in the fiber taper. Based on the understanding derived from this study, an improved heating and drawing design is proposed to achieve more homogeneity of stress in fiber optic taper during the drawing process.

Fiber Optic SERS Sensor with Silver Nanocubes Attached Based on Evanescent Wave for Detecting Pesticide Residues.

Surface-enhanced Raman scattering (SERS) has great potential in the field of rapid detection of pesticide residues in food. In this paper, a fiber optic SERS sensor excited by evanescent waves was proposed for efficient detection of thiram. Silver nanocubes (Ag NCs) were prepared as SERS active substrates, which had much stronger electromagnetic field intensity than nanospheres under laser excitation due to much more "hot spots". By using the method of electrostatic adsorption and laser induction, Ag NCs were uniformly assembled at the fiber taper waist (FTW) for enhancing the Raman signal. Different from the traditional way of stimulation, evanescent wave excitation greatly increased the interaction area between the excitation and analyte, while reducing the damage of the excited light to the metal nanostructures. The methods proposed in this work have been successfully used to detect the pesticide residues of thiram and showed good detection performance. The detection limits for 4-Mercaptobenzoic acid (4-MBA) and thiram were determined to be 10-9 and 10-8 M, the corresponding enhancement factor could be 1.64 × 105 and 6.38 × 104. Low concentration of thiram was detected in the peels of tomatoes and cucumbers, indicating its feasibility in actual sample detection. The combination of evanescent waves and SERS provides a new direction for the application of SERS sensors, which had great application potential in the field of pesticide residue detection.

Evaluation of Effect of Tape Edges on Tensile Properties of Chopped Carbon Fiber Tape Reinforced Thermoplastics by X-ray Grating Interferometry

Evaluation of Effect of Tape Edges on Tensile Properties of Chopped Carbon Fiber Tape Reinforced Thermoplastics by X-ray Grating Interferometry

Laser structure based on an erbium-doped fiber ring and a whispering gallery mode microbottle resonator.

A novel fiber laser structure, to the best of our knowledge, based on an erbium-doped fiber ring (EDFR) and a silica microbottle resonator (MBR) is proposed and investigated experimentally. Two fiber laser samples based on MBRs with different geometries and diameters of 200 and 150µm are fabricated, and their performance is studied experimentally. Periodic whispering gallery mode spectra of the MBRs are dependent on the position of the fiber taper used for coupling of light into the MBR, and this dependence is explored to achieve lasing at different wavelengths by moving the light coupling point along the axis of the microbottle incorporated into the proposed EDFR-MBR system. The influences of the pump laser power and light polarization on the system performance and laser stability are also investigated. Single-mode lasing with a maximum optical signal-to-noise ratio of 32dB is demonstrated.