Fiber Threads Research Articles

Automatic characterization of capillary flow profile of liquid samples on μTADs based on capacitance measurement

Capillary flow profile of liquid samples in porous media is closely related to the important properties of liquid samples, including the viscosity and the surface energy. Therefore, capillary flow profile can be used as an index to differentiate liquid samples with different properties. Fast and automatic characterization of capillary flow profile of liquid samples is necessary. In this work, we develop a portable and economical capacitance acquisition system (CASY) to easily obtain the capillary flow profile of liquid samples on microfluidic thread-based analytical devices (μTADs) by measuring the capacitance during the capillary flow. At first, we validate the accuracy of this method by comparing with the traditional method by video analysis in obtaining the capillary flow profiles in μTADs of cotton threads or glass fiber threads. Then we use it to differentiate liquid samples with different viscosity (mixture of water and glycerol). In addition, capillary flow profile on μTADs with chemical valves (chitosan or sucrose) can also be obtained on this device. Lastly, we show the potential of this device in measurement of hematocrit (HCT) of whole blood samples. This device can be used to catalog liquid biological samples with different properties in point-of-care diagnostics in the near future.

Efecto de mordientes sobre la variación de diámetro y tono de color en hilos de fibra de alpaca teñidos con flores de colli (Buddleja coriacea)

The aim of this study was to evaluate the effect of mordants on the variation of mean fibre diameter (MFD), spinning fineness (SF), and colour tone in alpaca fibre threads dyed with colli flowers (Buddleja coriacea). The dye was extracted using boiling water, followed by immersion of the thread in 160 ml of extract and post-mordanting with collpa, alum, and lemon salt at boiling temperature. MFD was measured using S-Fiber Med equipment. Colorimetry parameters were obtained using a spectrometer, and FT-IR spectrophotometer was used for identification of functional groups. MFD in colli-dyed and post-mordanted threads significantly increased with the addition of mordants, with the highest change observed with lemon salt (30.09 μm). The same trend was observed for SF. Dyeing with colli flower extract and subsequent mordant application produced different shades and hues of yellow colour in alpaca thread with significant variations in colorimetry parameters and FT-IR spectrum intensity. The reflectance spectrum R (%) showed a typical yellow colour curve with small differences in intensity due to the mordants used. In conclusion, MFD in colli-dyed thread increased by 0.44 µm; collpa mordanted by 2.78 µm; alum by 3.31 µm, and lemon salt by 3.51 µm compared to white thread, also producing different shades and hues of yellow colour with significant variations in colorimetry parameters and K/S. The sample dyed with colli without mordant presented the highest intensity, and lower intensity was observed in post-mordanted samples in FT-IR.

Preparation of Ceramic Fiber Threads with Enhanced Abrasion Resistance Performance.

Ceramic fiber thread is one of the key components in flexible external thermal insulation blankets, and it has been applied in various fields as a flexible ceramic fibrous material with excellent deformability and high-temperature resistance. However, ceramic fiber threads are often subjected to reciprocating friction motion at specific bending angles, making them highly susceptible to abrade and fracture. Enhancing the abrasion resistance performance of ceramic fiber threads under bending conditions is the future trend and remains a significant challenge. Hence, we design and construct a novel polyurethane-modified coating on the ceramic fiber threads to improve their abrasion resistance performance. The effects of the types and concentrations of modifiers on the microstructure, abrasion resistance property, and tensile property of ceramic fiber threads are systematically investigated. The ceramic fiber threads, after modification with hexamethylene diisocyanate waterborne polyurethane (HDI-WPU) with a concentration of 3%, exhibit excellent abrasion resistance properties. The number of friction cycles at fracture of the modified ceramic fiber thread is more than three times, and the tensile strength is more than one and a half times, that of the original ceramic fiber thread, demonstrating the great potential of the HDI-WPU modifier for enhancing the abrasion resistance performance of ceramic fiber threads.

Tensile Strength Improvements of Ramie Fiber Threads through Combination of Citric Acid and Sodium Hypophosphite Cross-Linking

Ramie (Boehmeria nivea) is believed to be one of the strongest natural fibers, but it still remains behind synthetic materials in terms of tensile strength. In this study, ramie materials were prepared to evaluate the modification crosslinking effect of natural fiber. The aim is to optimize various concentrations of citric acid (CA) crosslinking by adding Sodium hypophosphite (NaPO2H2), which is activated at different temperatures, to obtain the highest tensile mechanical strength. This crosslinking effect has been confirmed by FTIR to show the esterification process in the molecular structure of cellulose. The changes in the character of the fiber surface were analyzed by SEM. The tensile strength increased from 62.33 MPa for 0% CA to 124–172.86 MPa for decorticated fiber with a CA concentration of 0.75–1.875% (w/w). A significant increase in tensile strength was observed more than 19 times when CA/SHP 1% was treated at an activation temperature of 110 °C with a superior tensile strength of 1290.63. The fiber crosslinked with CA/SHP should be recommended for application of Natural Fiber Reinforced Polymer Composite (NFRPC), which has the potential to use in functional textile and industrial sector automotive or construction.

Fiber-Reinforced Clay: An Exploratory Study on Automated Thread Insertion for Enhanced Structural Integrity in LDM

This exploratory study examines the potential of combining clay and natural fiber material in liquid deposition modeling (LDM) to enhance the structural integrity of the soft-bodied print during the additive manufacturing (AM) process. For this purpose, a custom extruder module and a support structure have been developed as novel additions to the delta 3D printer that allows for automated fiber thread insertion into the deposit clay body and stabilize the 3D print during drying. This study explores material compatibility and durability in the liquid state and the material strength of the sintered ceramic body after pyrolysis of the natural fibers. The findings demonstrate the feasibility of an automated process for thread insertion and tensioning control to stabilize and control the 3D print until drying and showcase the versatile design possibilities of this method. The study may serve as a baseline for future research on fiber-reinforced clay printing in the construction industry and related disciplines.

Evaluation of Explosive Emission Carbon Fiber Cathodes for High-Power Microwave Devices

Most high-power microwave (HPM) sources, such as the magnetically insulated transmission line oscillator (MILO) being developed at Texas Tech, utilize cold cathodes that generate electrons via explosive emission. Highly emissive cathodes such as the presented can generate current densities and currents greater than 1 kA/cm 2 and 10 kA, respectively, which are required for devices that can output radio frequency (RF) power greater than 100 MW. Typically, these cathodes are made of materials such as metal, silk or synthetic velvet, carbon fiber, and cesium iodine (CsI)-coated carbon fiber. In order to optimize the MILO performance, we fabricated carbon fiber velvet cathodes and compare their performance with other commercially available carbon fiber cathodes. Fabrication was done on a manual, mechanical loom using commercially available carbon fiber thread. Four carbon fiber cathodes were tested: in-house fabricated monomodal carbon fiber velvet, in-house fabricated bimodal carbon fiber velvet, in-house fabricated carbon fiber plain weave cloth, and bimodal carbon fiber velvet manufactured by ESLI Inc. Testing was performed in a vacuum chamber with variable AK gap in the high vacuum range (10−7 torr). High-speed optical imaging was performed in order to determine the uniformity of the generated plasma as well as the e-beam. Voltage and current measurements were performed to determine diode impedance and perveance.

Productivity and quality of flax in the application of mineral fertilizers and folk fertilization of plants with the preparation Controlfit

Studies to assess the effect of foliar top dressing of flax with a silicon-containing preparation Controlfit were conducted on different backgrounds of mineral fertilizers in conditions of sod-podzolic medium loamy soil. The experiment was carried out in 2019-2021 on the field of a Separate subdivision of the Smolensk Research Institute of the Federal State Budget Research Institution – Federal Research Center for Bast Fiber Crops. The object of the study was a new variety of flax Phoenix, bred by Smolensk breeders. According to the results of the experiment, it was found that the yield of flax varied greatly over the years of the study, depending on weather conditions. On average, over 3 years of research, the highest yield of flax seeds was obtained on the variant with the maximum dose of mineral fertilizers N48P48K48 and amounted to 6.4 c/ha (83% of the control). Foliar top dressing with Controlfit did not change or even reduced the yield of flax seeds, as it led to the production of lighter seeds and fewer boxes on plants. The combined use of mineral fertilizers increased the yield of flax by 27-66%. The treatment of flax plants with the preparation Controlfit additionally increased the yield of straw by 31%. The effect of mineral fertilizers had a positive effect on the formation of long flax fiber, increasing its yield by 1.2 times relative to the control without fertilizers. Additional treatment of plants with Controlfit increased this indicator by 10-11%. The strength of flax fiber threads increased by 16% with an increase in the dose of mineral fertilizers and by 23% with the use of foliar fertilizing.

Fabrication and application of CNT fiber-ultra-fine diamond composites via electrophoretic deposition and instantaneous Joule-heating method

One-dimensional carbon nanotube (CNT) fibers combined with three-dimensional ultra-fine diamond have a synergistic effect that can be used in a variety of applications. The current challenge is how to combine the two materials quickly and efficiently. To actualize the combination of the two materials, a two-step method is adopted in this study. The electrophoretic deposition method, which allows ultra-fine diamond particles to adhere uniformly and controllably to the surface of carbon nanotube fibers. The instantaneous Joule-heating method can realize the instantaneous high-temperature recombination of diamond and CNT fibers. CNT fibers' flexibility and thermal conductivity are combined with ultra-fine diamond's high hardness in this composite. A polishing tool was made by knitting ultra-fine diamond/CNT fiber threads on non-woven fabric and used to dry polish potassium dihydrogen phosphate (KDP) crystals. CNT fibers were examined for wear, surface morphology, and KDP surface roughness before and after processing. The results reveal that the composite material-prepared tool has greater wear resistance and machining efficiency.

A Practical Approach for Uncertainty Management in Rubber Manufacturing Processes Using Physics-Informed Real-Time Models.

Industrial manufacturing management can benefit from the use of modeling. For a correct representation of the manufacturing process and the subsequent management, the models must incorporate the effect of the uncertainty propagation throughout the stages considered. In this paper, the proposed methodology for uncertainty management uses a nonintrusive method that is based on building a deterministic physics-informed real-time model for the a posteriori computation of output uncertainties. This model is built using tensor factorization as the Model Order Reduction technique. It includes as model parameters: material properties, process operations, and those random and epistemic uncertainties of known variables. The resulting model is used off-line to identify sensitivities and therefore to unify uncertainty management across the material transformation process. This method is presented by its direct application to an automotive door seal manufactured by continuous co-extrusion of several rubbers and reinforcement (metal strip and glass fiber thread).

Study of the Effect of Plasma Treatment on the Mechanical Properties of Mineral Fiber Threads

The article describes methods for modifying glass and basalt fibers and threads, and composite materials from them. Special attention is paid to plasma methods. Twisted glass thread and basalt twisted thread are investigated in the work. Plasma treatment was used to modify the threads. The type of plasma is nonequilibrium, low-temperature; the type of discharge is high-frequency capacitive. The results of research of thread properties, such as morphological changes and breaking load of threads. The plasma-treated and non-treated samples of threads were compared. The modes of plasma modification of threads in which the increase of breaking load strength of glass threads up to 23 % and of basalt threads up to 10 % is achieved have been established.

The effect of carbon fibre stitching on the tensile behaviour of secondary bonded single- and double-lap composite joints

This paper presents a novel stitching method for enhancing the mechanical properties of secondary-bonded CFRP single- and double-lap joints. In this approach, holes were drilled in the secondary bonded joints and carbon fibre threads were stitched through the joints. The vacuum resin infusion technique was then used to integrate the threads with the joints. The tensile properties of the stitched joints were measured and compared with those offered by traditional bonded (unstitched) joints in order to investigate the potential of the stitching method. The experimental results show that by using this stitching method, the ultimate tensile strength of the stitched single- and double-lap joints are respectively 200% and 130% greater than the corresponding conventional bonded joints.A three-dimensional finite element analysis (FEA) has been undertaken to predict the mechanical response of the stitched joints. The numerical analysis showed that the stiffness degradation at the end of overlap area is held back by the stitching fibres. Finally, the semi-empirical formulae has been developed to investigate the effect of hole pattern and thread size on the joint behaviour. Both the numerical and theoretical predictions are validated against the corresponding experimental results with good correlation.

Technologies for creating directional orientation of fiber reinforcement in concrete

Information on the analysis of methods for creating directional orientation of steel fiber rodding of reinforced concrete structures is presented. The design of a mobile experimental setup for the manufacture of fiber-concrete and fiber-reinforced concrete linear elements with a directional orientation of steel fibers by mechanical means has been developed. The test results of the pilot plant are presented. The required dimensions of the bunker for the fiber-reinforced concrete mixture, the type of the leveling element and the method of increasing the fiber-reinforced concrete mobility during casing using a pilot unit have been determined. The creation of a directed orientation of fiber threads in fiber-reinforced concrete makes it possible to make the most of this material‘s advantages. Despite a sufficient number of theoretically possible ways to create a directional orientation of fibers in a concrete mixture, not all of them can be applied in real construction conditions. Also, a number of methods introduce additional difficulties into the concreting process, which can adversely affect the construction processes duration. The use of a mechanical method for creating a directional orientation of steel fiber reinforcement in concrete made it possible to obtain the desired result on a mixture already containing fiber threads, without the need for their separate laying. The optimal design of the mechanical element leveling and the features of the process of leveling steel fibers in concrete have been established.

Joint Optimization of Test Node Selection and Fiber Thread Connection for Optical Communication Network

This paper proposes a method to solve the joint optimization of test node selection and fiber thread connection. The problem is modeled as an integer linear programming problem with two classes of decision variables. The first class of decision variables are composed of the number of parallel fiber threads throughout each potential testing route, the other class of decision variables are imposed just to denote whether a node is decided as a location to place testing equipment. The objective of the joint optimization is to minimize the number of nodes where fiber test equipment based on the optical time domain reflectometer are planned to locate. The objective function is just the sum of the second class of decision variables. Two types of linear constraints are needed. The first type of constraints describes the mutual relation between the two classes of variables, and the other type of constraints are formed to depict the impact of the number of fiber threads mounted within each fiber link on the first class of decision variables. Multiple examples are given to exhibit the advantage of joint optimization over heuristic method.

Highly Efficient Electrochemical Oxidation of Alcohols in a Flow Electrochemical Column Cell Modified with Au Nanoparticle Catalyst

Electrosynthesis is a powerful means for obtaining a variety of useful chemical products without employing toxic or otherwise hazardous chemical reagents and under relatively mild conditions. However, conventional batch-type cells suffer from a low productivity due to narrow two-dimensional reaction fields in the electrochemical system. To overcome this problem, we utilized continuous-flow column cell[1]. Although it was developed for a highly sensitive coulometric analysis of trace chemical substances in 1968, it is also expected to conduct rapid and quantitative bulk electrolysis due to its large electrode area and continuous-flow system. This flow cell consisted of a working electrode compartment and a counter electrode compartment, separated by an ion permeable Vycor® glass tube (Figure 1 (a)). A bundle of carbon fiber threads was tightly packed as a working electrode in the continuous-flow column cell, and a Pt spiral wire was used as a counter electrode. During several decades, the bulk gold has been considered as less active material, but at nanoscale, it exhibits surprisingly physicochemical and catalytic properties[2]. Therefore, in this work, the carbon fiber surface was also functionalized with Au nanoparticle catalyst to promote an electrochemical oxidation of alcohols.As a result, we have successfully demonstrated an efficient electrocatalytic oxidation of benzyl alcohol to provide benzaldehyde and benzoic acid with high current efficiencies in alkaline media. Moreover, it was also found that the selectivity of benzaldehyde was influenced by the added base amounts, and increased up to 97% by decreasing the amounts. We will also report the results of electrochemical oxidation of other alcohols.

Mechanical behaviour of composite laminates repaired with a stitched scarf patch

In order to increase the service life and maintain the residual strength of damaged composite structures, it is necessary to investigate effective repairing techniques. In this paper, an innovative stitch-reinforced scarf patch is developed in order to reduce the amount of parent material that is removed during the repair. Carbon fibre threads are used to stitch the scarf patch to a damaged carbon fibre laminate via pre-drilled holes. Following stitching, the vacuum resin infusion technique is used to infuse the carbon fibre threads, thereby fixing the patch to the parent part. Here, the effects of varying both the hole diameter and the scarf angle on the load-carrying capacity of the repaired laminates are studied. The tensile strength, strain distribution and failure mechanisms are investigated using the digital image correlation (DIC) technique. The results show that by introducing a 2.5 mm diameter stitching hole, the ultimate tensile strength of repaired laminates related to three scarf angles is increased by up to 20, 27 and 45% respectively, relative to traditional laminates with an equivalent scarf ratio.

Side-viewing photoacoustic waveguide endoscopy

Side-viewing hollow optical waveguides allow for minimally invasive endoscopy by concentrically guiding light and sound for photoacoustic generation and detection. Here, we characterize the side-viewing photoacoustic waveguide (PWG) endoscope by scanning 7.2 μm diameter carbon fiber threads within phantom tissues and animal tissues. Photoacoustic signals are carried along the 5.5 and 10.0 cm length of the PWG with minimal attenuation. Thus, this technology enables 360°, deep-tissue photoacoustic imaging. Photoacoustic signals were identified up to 8.0 mm from the PWG imaging window in an optically clear medium. The outer diameter of this device is measured as just over 1.0 mm, with the potential to be further miniaturized due to its unique design. The PWG is an ideal candidate for a myriad of pre-clinical and clinical applications where typical photoacoustic endoscopy systems are impractical, due to their size. Presented here, is the first side-viewing photoacoustic waveguide endoscope.

Manufacturing and mechanical characterisation of polyurethane resin based sandwich composites for three-dimensional fabric reinforcement

Three-dimensional (3D) sandwich composites are an excellent material, boasting light weight, high strength, and high specific stiffness. For materials comprising this structure, a new type of sandwich composite, made with a 3D fabric reinforcement structure, was independently developed. A sandwich composite is a lightweight composite with practical mechanical properties, manufactured using compression moulding techniques. The 3D fabrics were produced by sewing jute yarns having configurable structures using Kevlar fibre threads, while an epoxy resin was impregnated into the 3D fabrics, achieving a more uniform resin and voids distribution and thus a better polyurethane resin impregnation for the sandwich composite. Jute composite panels were used to form the upper and lower skins during the compression moulding process. The composites had been subjected to compression, flexural and impact tests, and their fracture surfaces had been characterised by scanning electron microscopy (SEM). Mechanical tests showed that the compression and flexural strengths of the composites markedly increased, reaching 21.4 and 18.5 MPa respectively, which was approximately 7.7 and 3.8 times higher than similar properties of the blank composites without 3D fabrics. SEM micrographs of the composites showed the presence of jute fibre pull-outs in the 3D fabrics and the existence of voids in the composite.

Highly self-healable and flexible cable-type pH sensors for real-time monitoring of human fluids

Development of sensing technology with wearable chemical sensors is realizing non-invasive, real-time monitoring healthcare and disease diagnostics. The advanced sensor devices should be compact and portable for use in limited space, easy to wear on human body, and low-cost for personalized healthcare markets. Here, we report a highly sensitive, flexible, and autonomously self-healable pH sensor cable developed by weaving together two carbon fiber thread electrodes coated with mechanically robust self-healing polymers. The pH sensor cable showed excellent electrochemical performances of sensitivity, repeatability, and durability. Spontaneous and autonomous sensor healing efficiency of the pH sensor cable was demonstrated by measuring sensitivity during four cycles of cutting and healing process. The pH sensor cable could measure pH in small volumes of real human fluid samples, including urine, saliva, and sweat, and the results were similar to those of a commercial pH meter. Taken together, successful real-time pH monitoring for human sweat was demonstrated by fabricating a wearable sensing system in which the pH sensor cable was knitted into a headband integrated with wireless electronics.

Extremely Fast Self-Healable Bio-Based Supramolecular Polymer for Wearable Real-Time Sweat-Monitoring Sensor.

Sensors with autonomous self-healing properties offer enhanced durability, reliability, and stability. Although numerous self-healing polymers have been attempted, achieving sensors with fast and reversible recovery under ambient conditions with high mechanical toughness remains challenging. Here, a highly sensitive wearable sensor made of a robust bio-based supramolecular polymer that is capable of self-healing via hydrogen bonding is presented. The integration of carbon fiber thread into a self-healing polymer matrix provides a new toolset that can easily be knitted into textile items to fabricate wearable sensors that show impressive self-healing efficiency (>97.0%) after 30 s at room temperature for K+/Na+ sensing. The wearable sweat-sensor system-coupled with a wireless electronic circuit board capable of transferring data to a smart phone-successfully monitors electrolyte ions in human perspiration noninvasively in real time, even in the healed state during indoor exercise. Our smart sensors represent an important advance toward futuristic personalized healthcare applications.

Fabrication of fixed polishing tool by knitting diamond/CNT fiber threads on cloth

In this paper, a novel polishing tool has been prepared by knitting diamond/CNT fiber threads on cloth. Diamond particles are adhered to the surface of CNT fibers which are immersed in the diamond solution. Heat treatment is used to fix diamond abrasives on the CNT fibers, and the corresponding experimental parameters are discussed. Then the diamond/CNT fiber threads are knitted on cloth by method of cross-stitch and the processing performance of polishing tool is evaluated. Results reveal that the concentration of diamond solution and immersing time have great effect on the amount and uniformity of diamond on the surface of the fiber. And the effect of adhesion get an ideal result when the concentration of diamond is 0.5 wt% and the immersing time is 5 min. Diamond particles are bond with carbon nanotube fibers under heat treatment conditions, and the effect on the tensile strength of the fiber is obvious. Proper heat treatment parameters make it reach to 168.74 Mpa compared with the original's 83.35 Mpa, increased by 102.4%. The fixed diamond abrasives polishing tool is used to process agalmatolite, whose performance is compared with polishing tool made of pristine carbon nanotube fibers, and results indicate that the former has certain removal effect, and its wear resistance is better than the latter.