Spiral Fiber Research Articles

Ultra-Stretchable Spiral Hybrid Conductive Fiber with 500%-Strain Electric Stability and Deformation-Independent Linear Temperature Response.

Stretchable configuration occupies priority in devising flexible conductors used in intelligent electronics and implantable sensors. While most conductive configurations cannot suppress electrical variations against extreme deformation and ignore inherent material characteristics. Herein, a spiral hybrid conductive fiber (SHCF) composed of aramid polymeric matrix and silver nanowires (AgNWs) coating is fabricated through shaping and dipping processes. The homochiral coiled configuration mimicked by plant tendrils not only enables its high elongation (958%), but also generates a superior deformation-insensitive effect to existing stretchable conductors. The resistance of SHCF maintains remarkable stability against extreme strain (500%), impact damage, air exposure (90 days), and cyclic bending (150000 times). Moreover, the thermal-induced densification of AgNWs on SHCF achieves precise and linear temperature response toward a broad range (-20 to 100 °C). Its sensitivity further manifests high independence to tensile strain (0%-500%), allowing for flexible temperature monitoring of curved objects. Such unique strain-tolerant electrical stability and thermosensation hold broad prospects for SHCF in lossless power transferring and expeditious thermal analysis.

Tailoring surface features and pore structure by carbon spiral fibers to construct the high-strength carbon foams for the fast and cyclic photo-thermal oil absorption

Two key limitations affecting the commercial application of carbon foams for fast clean-up of varied oils are the complex synthesis process and poor mechanical stability. In this work, an effective method is reported to fabricate the efficient oil-absorbing materials (CSF@MCF) of carbon spiral fibers (CSFs) anchored on melamine carbon foam (MCF) with superior mechanical properties and excellent photothermal conversion. The interwoven CSFs can not only provide extra rigidity but also reduce the stress concentration of the carbon skeleton, which greatly improves the mechanical properties with 6.3 times maximum compression stress and 4.5 times ultimate tensile strength than MCF. In addition, the pure carbon component can reduce the interface resistance and excite the free electrons more easily, thus realizing high-efficiency photothermal conversion in a wide range of wavelengths. Under light irradiation, the CSF@MCF can be quickly heated up to 70 °C and achieve ultra-high absorption of crude oil, up to 62 g g−1, due to its low density and large absorption volume. Meanwhile, the CSF@MCF exhibits impressive absorption stability with persistent superhydrophobicity and a high recovery efficiency of over 85%. Superadding its simple preparation process, low production cost, and excellent acid-alkali resistance, the CSF@MCF shows great commercial potential for effectively absorbing varied oils.

Bionic artificial penile Tunica albuginea

Bionic artificial penile Tunica albuginea

ZrB 2–SiC spiral fibers prepared by combining liquid rope effect with non-solvent-induced phase separation method: A promising toughening material for ultra-high temperature ceramics

Spiral fibers were considered to be an ideal toughening phase of ultra-high torsional release effect. In this work, ZrB₂ (Z)–20 vol% SiC (S) spiral fiber (ZS_sf) with controllable structure was prepared by a combination approach of liquid rope effect and non-solvent-induced phase separation. Dominantly depended on the kinematic viscosity (<i>η</i>), dropping height (<i>H</i>), and flow rate (<i>Q</i>), the geometric parameters of ZS_sf involving filament diameter (<i>d</i>) and coil diameter (<i>D</i>) were followed the relationship of <i>d ≈</i> 0.516×10⁻³<i>Q</i>^1/2<i>H</i>^−1/4 and <i>D ≈</i> 0.25×10^–3(<i>Q</i>/<i>H</i>)^1/3, respectively, within the optimized <i>η</i> of 10–15 Pa·s. Three different microstructures of ZS_sf were achieved by adjusting the polymer/solvent/non-solvent system assisted with phase diagram calculation, including dense, hollow, and hierarchical pore structures. The ZrB₂–SiC with 1 wt% ZS_sf composites prepared by hot isostatic pressing (HIP) exhibited a ~30% increase in fracture toughness (<i>K</i>_IC, 4.41 MPa·m^1/2) compared with the ZrB₂–SiC composite, where the microscopic fracture toughness of the ZS_sf was ~80% higher than that of the matrix. The fibers with a ~10 nm <i>in-situ-</i>synthesized graphite phase amongst grain boundaries of ZrB₂ and SiC changed the fracture mode, and promoted the crack deflection and pull-out adjacent the interface of matrix and the fiber.

Study on the characteristics of four electrode wide constant temperature region for preparing high quality spiral fiber

Study on the characteristics of four electrode wide constant temperature region for preparing high quality spiral fiber

Compressive Strength and Porosity Evaluation of Innovative Bidirectional Spiral Winding Fiber Reinforced Composites.

The aim of this in vitro study was to investigate the compressive strength and the bulk porosity of a bidirectional (bFRC) and an experimental bidirectional spiral winding reinforced fiber composite (bswFRC). Cylindrical-shape specimens were prepared for each material group and processed for the evaluation of compressive strength after different storage conditions (dry, 1 and 3 months) in distilled water at 37 °C. The specimens were also assessed for the degree of bulk porosity through X-ray tomography. A scanning electron microscope (SEM) was used to determine the fracture mode after a compressive strength test. Data were statistically analyzed using Two-Way Analysis of Variance (ANOVA). A significantly lower compressive strength was obtained in dry conditions, and after 1 month of water immersion, with the specimens created with bFRC compared to those made with bswFRC (p &lt; 0.05). No significant difference (p &gt; 0.05) was found between the two groups after 3 months of water immersion. However, the presence of water jeopardized significantly the compressive strength of bswFRC after water storage. The type of fracture was clearly different between the two groups; bswFRC showed a brutal fracture, whilst bFRC demonstrated a shear fracture. The bswFRC demonstrated higher pore volume density than bFRC. In conclusion, bswFRC is characterized by greater compressive strength compared to bFRC in dry conditions, but water-aging can significantly decrease the mechanical properties of such an innovative FRC. Therefore, both the novel bidirectional spiral winding reinforced fiber composites (bswFRC) and the bidirectional fiber reinforced composites (bFRC) might represent suitable materials for the production of post-and-core systems via CAD/CAM technology. These findings suggest that both FRC materials have the potential to strengthen the endodontically treated teeth.

Machine learning prediction of fiber pull-out and bond-slip in fiber-reinforced cementitious composites

Single fiber pull-out and fiber-matrix interfacial interaction play an essential role in understanding the mechanical behavior of fiber-reinforced cementitious composites. The present study introduces a computational model for predicting the maximum fiber pull-out force and corresponding bond slip. An extensive literature survey was performed to create a pertinent comprehensive experimental database. A total of 382 experimental data were utilized to develop and train the Artificial Neural Network (ANN) models. The model input parameters included the fiber embedded length, fiber inclination angle, fiber tensile strength, fiber length-to-diameter ratio, loading rate, water-to-cement ratio, concrete compressive strength, and fiber geometry. The model output consisted of the maximum pull-out force and corresponding slip. The results indicate that ANN with two hidden layers and 12 neurons was adequate for predicting the outputs with a mean absolute percentage error (MAPE) of less than 10%. To obtain the importance of the inputs on the outputs (the maximum fiber pull-out force and the corresponding slip), a sensitivity analysis was done based on the Milne formula on the proposed ANN. According to the results, it was found that among the eight inputs, the parameters of the geometric shape of the fibers (straight, hooked-end and spiral fibers) and fiber tensile strength have the highest effect on the outputs, with an impact percentage of 16.1 and 15.1, respectively. The mean square error (MSE) was 0.9 for the maximum pull-out force and 0.14 for slip, respectively. Overall, the proposed executed model attained reasonable predictions and could offer a data driven approach to optimizing fiber-reinforced cementitious composites.

Experimental investigation on the performance of engineered spiral fiber: Fiber pull-out and direct tension tests

Recent researches indicate promising characteristics of Engineered Spirally Deformed steel Fiber (SDF) for reinforcing cementitious matrixes. However, the available research includes only limited SDF pull-out tests (mostly vertically aligned fibers) and flexural beam tests on Spirally Deformed Fiber Reinforced Concrete (SDFRC). This paper performed a complete single SDF pull-out and several direct tension tests on dog-bone SDFRC specimens with a proposed fully hinged apparatus to fill the research gaps. Various test parameters were considered in the SDF pull-out study, including matrix strength (20 MPa and 30 MPa) as well as fiber embedment length (10 mm, 15 mm, and 20 mm) and inclination angle (0˚, 15˚, 30˚, 45˚, and 60˚) of the fiber. SDFRC strength (20 MPa and 30 MPa) and fiber volume fraction (0.15 % and 0.25 %) were considered in the direct tension tests of SDFRC. Spiral fibers presented promising energy absorption capacity. Consistent with the outcomes of other fiber pull-out studies, the current study found that the matrix strength positively correlates with peak and post-peak pull-out load, while the fiber embedded length and inclination angle correlated inversely with loads. However, unlike other fully deformed fibers, the inverse correlation between the fiber embedded length and loads is considerably less pronounced. The direct tension tests revealed that such a fiber sustains load bearing even in significant cracks (widths ≥ 15 mm).

Experimental study of reinforced concrete beams reinforced with hybrid spiral-hooked end steel fibres under static and impact loads

Discrete short steel fibres were proposed to be mixed with concrete for arresting cracks and enhancing the post-cracking resistance. It has been proven in previous tests that spiral steel fibres possessed markedly higher bonding to concrete matrix, leading to significantly improved performance of steel fibre reinforced concrete (SFRC) in terms of crack controllability, impact resistance, deformability and energy absorption capability. However, at the initial stage of cracking, SFRC reinforced with spiral fibres has relatively lower resistance to crack opening as compared to that reinforced with other types of steel fibres because of spiral shape stretching. To overcome this shortcoming, in the present study, short hooked-end steel fibres that exhibit high pull-out resistance at the crack initiation stage were mixed with spiral steel fibres in the normal-strength concrete matrix. A total volume fraction of 1% of hybrid steel fibres was mixed to cast SFRC specimens. With various mix ratios between spiral and hooked-end fibres considered, five batches of SFRC specimens were tested. Uniaxial compressive tests and four-point bending tests were carried out to compare the mechanical properties of SFRC materials with hybrid fibres while three-point bending tests on SFRC structural beams under static, drop-weight impact and post-impact static loading tests were conducted to investigate the structural performances. An equal dosage of hooked-end and spiral fibres was found to outperform other blend proportions to provide synergetic reinforcement to concrete matrix in terms of post-cracking resistance, energy absorption capacity and post-impact performance.

Scheme Design of Xenon Composite Over-wrapped Pressure Vessel for Electric Propulsion System

The composite over-wrapped pressure vessel (COPV), which were made by ultra-thin metal liner and high strength carbon fiber reinforced plastic (CFRP), has high performance factor (PV/W). COPV were widely used in electric propulsion system (EPS) of space system. ANSI/AIAA S-081-2000 is a general standard for pressure vessel of aerospace field at home and abroad, it specified the design elements, references, specifications, requirements in detail. The materials selection of liner, CFRP and skirt are introduced respectively. The design contents of liner and CFRP are explained. The liner is designed in terms of equal strength principle and the composite structure was designed in term of hoop fiber layers and spiral fiber layers alternately over-wrapped. The skirt is composite structure, with X-X carbon fiber over-wrapped the TC4 titanium alloy. The titanium liner thickness is 0.8mm, Cycle life is at last 100 times when the liner thick is ultra-thin. The safe life was designed, including stress-rupture life and low cycle fatigue-life. The leak before burst (LBB)safe failure mode was analyzed. The results show that the structure design meets the technical requirements.

3D meso-scale modelling of tensile and compressive fracture behaviour of steel fibre reinforced concrete

This paper presents a novel meso-scale modelling framework to investigate the fracture process in steel fibre reinforced concrete (SFRC) under uniaxial tension and compression considering its 3D mesostructural characteristics, including different types of fibres, realistic shaped aggregates, mortar, interfacial transition zone and voids. Based on a hybrid damage model consisting of cohesive element method and damage plasticity method, a cost-effective finite element approach was proposed to simulate the fracture behaviour of SFRC in terms of stress–strain response, energy dissipation and crack morphology. The results indicated that under given conditions, the straight and hooked-end fibres improved the compressive damage tolerances of concrete over 11.5% while the spiral fibres had a negligible effect of 2.6%. The tensile macro-damage level index introduced was reduced over 15% by all fibres. Compared to straight fibres, the higher anchoring capacity of spiral fibres reduced the reinforcement performance while hooked-end fibres did not exhibit a significant influence.

β-Cyclodextrin and Oligoarginine Peptide-Based Dendrimer-Entrapped Gold Nanoparticles for Improving Drug Delivery to the Inner Ear.

Here, we developed a safe and highly effective nanocarrier using β-cyclodextrin (β-CD) and oligoarginine peptide (Arg8)-modified dendrimer-entrapped gold nanoparticles (Au@CD-PAMAM-Arg8), with a diameter of 5 nm, for improved delivery of dexamethasone (Dex) to the inner ear. The properties and in vivo distribution of the Au@CD-PAMAM-Arg8 were assessed in vitro, and a streptomycin (SM) ototoxicity model was used in vivo. Flow cytometry analysis of HEIOC1 cells treated with Au@CD-PAMAM-Arg8 and Au @CD-PAMAM at different time intervals indicated that cell uptake efficiency of the drug delivery carrier Au@CD-PAMAM-Arg8 was higher than that of Au @CD-PAMAM. Au@CD-PAMAM-Arg8 carrying Dex (Au@CD-PAMAM-Arg8/Dex) were mainly distributed in hair cells, the spiral ganglion, lateral wall, and nerve fibers and had stronger protective effects on the inner ear than Dex administration alone. In vivo tracer tests revealed that tympanic injection was significantly more effective than posterior ear injection, muscle injection, and tail vein injection, whereas clinical retro-auricular injection could not increase the efficiency of drug delivery into the ear. Electrocochleography results showed that Au@CD-PAMAM-Arg8/Dex significantly improved hearing in C57/BL6 mice after SM exposure. These findings indicate that Au@CD-PAMAM-Arg8 may be the useful drug carriers for the treatment of inner ear diseases.

Conjugate heat and mass transfer in a counter-flow spiral hollow fiber membrane tube bank for liquid desiccant air dehumidification

Membrane contactor formed by spiral hollow fiber membrane tube bank (SPHFMTB) or straight bank (STHFMTB) has been employed for liquid desiccant air dehumidification. Comparative analysis on the dehumidification performance and the conjugate heat and mass transfer characteristics inside the membrane contactors are carefully investigated. The calculation domains contain straight and spiral types of hollow fiber semi-permeable membrane tubes and two internal streams in a counter-flow arrangement. The product of friction factor and Reynolds number fRea, Nusselt and Sherwood numbers (Nua and Sha) of the airflow for various tube numbers (4, 7, 9) and pitch ratios (0.6, 0.3, ∞) are obtained. It is found that the SPHFMTBs exhibit better moisture removal ability than the STHFMTBs. The fully developed mean Nua and fRea numbers increase with the Reynolds number of the air stream Rea for the both SPHFMTBs and STHFMTBs. Though the SPHFMTBs are relatively more beneficial to enhancement of heat transfer, the corresponding flow resistance is added as well. The relevant data obtained from the present simulation are expected to promote the development of the geometry optimization on hollow fiber membrane tube bank.

Probing the effect of thickener microstructure on rheological and tribological properties of grease

The thickener microstructure strongly determines the properties of lubricating grease. Here, four types of grease were synthesized through different thickeners (lithium complex soap, polyurea, calcium sulfonate complex soap, bentonite), thickening polyalphaolefin. The influence of the thickener microstructure on the physicochemical, rheological, and tribological properties was evaluated. Results show that the lithium complex soap with a spiral fiber structure shows the best physicochemical properties and the highest yield stress. The four greases show the shear-thinning behavior because of the deformation of the thickener structures. The calcium sulfonate complex soap with a dense porous structure presents optimal tribological properties because of the synergy effect of the thickener deposited film and the tribo-chemical reaction film.

A liquid level sensor based on spiral macro-bending plastic optical fiber

Liquid level sensing refers to the monitoring of liquid level height information under working or static conditions. Compared with traditional liquid level monitoring methods, optical fiber liquid level sensor has advantages of immunity to electromagnetic interference, excellent electronic insulation and remote operation. The light propagates in the fiber through total internal reflection. When the fiber is bent, a large number of cladding modes will be generated. These cladding modes will have Fresnel reflection at the interface between the bent cladding and environment. When the high refractive index medium is in contact with or close to the fiber cladding, part of the cladding mode light will leak into the external medium, resulting in light energy loss. Therefore, according to the basic working principle of optical fiber macro-bending loss, a new type of spiral plastic optical fiber (POF) liquid level sensor was designed. The POF with a diameter of 0.5 mm was used as the sensing optical fiber, and then it was spirally wound and fixed on a self-designed square cylinder. The liquid level was monitored by the designed sensor, and the effects of environment and liquid temperature on the test process were analyzed. The results show: (i) the measuring range of the liquid level sensing system is within 80 mm and it has good repeatability; (ii) the resolution and sensitivity are 1.03 mm and 0.088 dB/mm, respectively; (iii) the influence of temperature on the sensor is less than 0.06 dB/℃.

Local texture and back-end defect in hot extruded AZ91 magnesium alloy

Abstract Local texture in hot extruded MgAl9Zn1 alloy has been studied using individual grain orientation measurement (BKD, “Automated EBSD”) in the SEM. In the shaft of a partial extrudate through a circular die orifice, a &lt;0001&gt; ring fiber texture has formed which continuously changes into a spiral fiber texture in the bottom neck. The flow tube of the internal back-end extrusion defect has a distinctly different texture whereby the (0002) lattice planes are preferentially aligned parallel to the radial and the extrusion directions. The formation of this texture is explained by basal glide, the pile-up of the hard billet mantle, and the inhomo-geneous metal flow during the extrusion process.

Experimental Investigation on the Performance of Engineered Spiral Fiber: Fiber Pull-Out and Direct Tension Tests

Experimental Investigation on the Performance of Engineered Spiral Fiber: Fiber Pull-Out and Direct Tension Tests

Fabrication of tunable oxygen vacancies on BiOCl modified by spiral carbon fiber for highly efficient photocatalytic detoxification of typical pollutants

Flower-like spiral carbon fiber (SCF)/BiOCl composite photocatalysts with adjustable oxygen vacancies (OVs) were successfully fabricated via SCF surface modification of BiOCl. The sample composition and the photogenerated carrier separation efficiency were tested by various characterization methods. Compared with BiOCl, SCF/BiOCl photocatalysts display higher level of OVs and produce more superoxide radicals. The presence of OVs leads to the formation of an impurity energy level between the energy band of BiOCl. In addition, the SCF can transfer some of the photogenerated electrons produced by BiOCl. With the synergistic effect of OVs and SCF, an effective separation of photogenerated carriers is achieved. Photocatalytic activity of the samples was evaluated by the removal of inorganic pollutants (Cr (VI)) and organic pollutants (phenol and Tetracycline (TC)). The activity results show that SCF/BOC-1.75 for TC, phenol and Cr (VI) is 3.2, 2.5 and 10.6 times of that of the neat BOC; 0.9, 1.8 and 4.9 times of that of P25 under simulated sunlight illumination, respectively. The primary active species in the reaction system were investigated and the reaction mechanism was deduced.

Microscopic features and phytochemistry of two Congolese medicinal plants: Aframomum alboviolaceum (Ridley) K. Schum, and Aframomum angustifolium (Sonn.) K. Schum. (Zingiberaceae).

The leaves and seeds of Aframomum alboviolaceum and Aframomum angustifolium are specifically used by traditional healers in the Democratic Republic of Congo (DRC) for the treatment of several pathologies. The aim of present study was to determine the microscopic characteristics and phytochemical composition of these species of the genus Aframomum. The microscopic study of these plants revealed the presence of punctate vessels, fiber cluster with calcium oxalate crystals, isolated unicellular hair, fibers, starch grains, spiral vessel fragments, fiber fragments, and indistinct parenchyma fragments. Phytochemical screening revealed several chemical groups such as phenolic acids, flavonoids, coumarins, alkaloids, terpenes, iridoids, saponins etc. The determination of total polyphenols, flavonoids and tannins gave contents ranging from 14.95 ± 0.45 and 63.98 ± 2.04 mgGAE/g, 0.16 ± 0.01 and 10.68 ± 0.32 mgQE/g and between 1.28 ± 0.03 and 28.51 ± 0.56 mg CAE/g respectively. In general, the leaves are richer in secondary metabolites, polyphenols, flavonoids and tannin than the seeds. Both plants also contain iron, magnesium, calcium and sodium. To our knowledge, this is the first time that histological elements have been identified in the leaves and seeds of A. angustifolium.

A Spiral Distributed Monitoring Method for Steel Rebar Corrosion.

This paper proposes a novel spiral-wound, optic-fiber sensor to monitor the corrosion of steel bars. At the same time, the winding parameters, such as winding angle and pitch, were first theoretically deduced. Then, to decrease light loss, a practically distributed sensor wound onto the protective mortar layer was developed by increasing the winding curvature radius. The spiral distributed sensors were experimentally verified for their feasibility. Experimental results showed that the spiral fiber strain depended on the thickness of the protective mortar layer. Furthermore, the spiral distributed strain well reflected the cracking process of concrete. In addition, the concrete cracking time depended on the thickness of the protective concrete layer. Accordingly, this method is feasible for evaluating the initial and final cracking behaviors of concrete structures and provides a sight for steel bar corrosion.