Solid Fiber Research Articles

Hollow Co/CoO/Carbon nanofibers promoted PMS decomposition for the degradation of Rhodamine B

Carbon nanofibers with hollow structures have an excellent application prospect in various fields because of their high specific surface area and abundant active sites. PAN-based hollow carbon nanofiber doped with Co/CoO (H–Co/CoO–CNF) was successfully prepared and used as a catalyst to activate peroxymonosulfate (PMS) and degrade Rhodamine B (RhB). The catalyst showed a surprising degradation rate (98.89%) of RhB within 15 min and had good degradation performance in a wide pH range (pH 1.5–11.2). Compared with solid fibers, H–Co/CoO–CNF shows better cyclic characteristics. The catalyst is also magnetic and recoverable easily due to the addition of Co/CoO. Two pathways of both radical (SO4•−) and non-radical (1O2) exist during the RhB degradation process are confirmed through electron paramagnetic resonance (EPR) analysis and radical quenching experiments. This work provides a new idea for hollow fibers loaded with metals and their oxides and can guide the development of catalysts for advanced oxidation processes in the future.

Effect of Human Hair Fibers on the Performance of Concrete Incorporating High Dosage of Silica Fume

Sustainable development in structural materials is currently getting attention all around the world. Solid waste, building and demolition waste, natural resources, and their reuse are the most obvious strategies for achieving sustainability in the construction industry. Solid waste human hair fiber (HHF) with a diameter of 70 µm and a length of 30–40 mm is used as a fiber, having a dosage of 0%, 1%, 1.5%, 2%, 3%, 4%, and 5%, while silica fume (SF) with a dosage of 0%, 5%, 10%, 15%, 20%, 25%, and 30% is used as a cement substitute. A drop of 50 mm to 75 mm slump was witnessed for the water–cement ratio used in the M20 mix design of concrete. The concrete’s mechanical properties, such as compressive, split tensile, and flexural strength, were determined after 28 days of water curing. The concept of the response surface methodology (RSM) for optimizing human hair fiber concrete (HHFC) and SF substitution was used, which was validated by the polynomial work expectation. The model is statistically significant when the fluctuation of the analysis of variance (ANOVA) is analyzed using a p-value with a significance level of 0.05. The test results showed that the use of 2% human hair as fiber and 15% SF as a cementitious additive or cement replacement considerably improved the strength of concrete. The compressive, flexural, and split tensile strengths of HHFC improved by 14%, 8%, and 7%, respectively, which shows the significance of human hair and the partial replacement of cement with SF. Moreover, SEM analysis was carried out to study the microstructure of the concrete matrix.

Massive production of fibroin nano-fibrous biomaterial by turbulent co-flow

Among the different polymers (proteins, polysaccharides, etc.) that make up natural fibers, fibroin is a protein produced by silk spinning animals, which have developed an optimized system for the conversion of a highly concentrated solution of this protein into high-performance solid fibers. This protein undergoes a self-assembly process in the silk glands that result from chemical gradients and by the application of mechanical stresses during the last step of the process. In the quest for a process that could mimic natural spinning at massive scales, we have discovered that turbulence offers a novel and promising solution: a turbulent liquid jet can be formed by a chemically green and simple coagulating liquid (a diluted solution of acetic acid in etanol) co-flowing with a concentrated solution of fibroin in water by the use of a Flow Blurring nebulizer. In this system, (a) the co-flowing coagulant liquid extracts water from the original protein solution and, simultaneously, (b) the self-assembled proteins are subjected to mechanical actions, including splitting and stretching. Given the non-negligible produced content with the size and appearance of natural silk, the stochastic distribution of those effects in our process should contain the range of natural ones found in animals. The resulting easily functionalizable and tunable one-step material is 100% biocompatible, and our method a perfect candidate to large-scale, low-cost, green and sustainable processing of fibroin for fibres and textiles.

Liquid Oil Trapped inside PVA Electrospun Microcapsules.

Electrospinning makes it possible to obtain solid fibers, in addition to core-shell fibers, using coextrusion. However, an exhaustive control of parameters allows the core-shell fibers from emulsion electrospinning to be obtained. The solvent in the outer surface tends to evaporate and the polymer density increases, moving the emulsion drops towards the center, which in turn promotes coalescence, thus creating the core. The aim of this work was to avoid coalescence and obtain a net of nanofibers entrapping oil microcapsules. We obtained an emulsion oil in water (O/W), with polyvinyl alcohol (W) and two essential oils (O), sage and thyme. An electrospinning process was used to place the microcapsules of oil inside a net of nanofibers. The electrospun veil was characterized by organoleptic testing, SEM microscopy, FTIR spectroscopy, DSC thermal analysis, and pressure tests. Organoleptic testing, FTIR spectroscopy, and DSC thermal analysis demonstrated the presence of the oil, which was retained in the spheres observed by SEM microscopy, while pressure tests revealed that the oil remained in a liquid state. Furthermore, we demonstrated a strong relationship between the emulsion size and the final microcapsules created, which are slightly larger due to the shell formation. The size of the emulsion determines whether the spheres will be independent or embedded in the nanofibers. Furthermore, the nanofiber diameter was considerably reduced compared to the nanofibers without the oil.

Hierarchical Synthesis of MnO2/NiCo2S4 on the Graphenized Pencil Lead and Application as Solid Phase Microextraction Fiber for Mensuration of Polycyclic Aromatic Hydrocarbons in Surface Water Samples

The main goal of this study is the hierarchical synthesis nano structure MnO2/NiCo2S4 on the graphenized pencil lead and application as solid phase microextraction fiber for mensuration of polycyclic aromatic hydrocarbons in surface water samples. In this study, MnO2/NiCo2S4/GPL fiber was synthesized by hydrothermal method and characterized by EDX, SEM and FT-IR. Then its extraction efficiency for polycyclic aromatic hydrocarbons (PAHs) in surface water samples via the HS-SPME method was evaluated. The results revealed that prepared fiber is appropriate for quantitative determination. Identification of desorbed analytes from the surface of fiber was performed in combination GC-FID. Under the optimized conditions, the linear response for the analytes was observed in the range from 0.0001 to 100 µgL−1 with the correlation coefficients (R 2) ranged from 0.994 to 0.998 and the limits of detection (LOD) between 0.3 and 0.05 ngL−1. The proposed fiber was successfully used for the determination of polycyclic aromatic hydrocarbons spiked in surface water samples and RSD% values were obtaine in the range of 8.4 − 9.8%.

Designing multi-mode anti-resonant hollow-core fibers for industrial laser power delivery

We investigate the design of hollow-core fibers for the delivery of 10s of kilowatt average power from multi-mode laser sources. For such lasers, delivery through solid-core fibers is typically limited by nonlinear optical effects to 10s of meters of distance. Techniques are presented here for the design of multi-mode anti-resonant fibers that can efficiently couple and transmit light from these lasers. By numerical simulation we analyze the performance of two anti-resonant fibers targeting continuous-wave lasers with M2 up to 13 and find they are capable of delivering MW-level power over several kilometers with low leakage loss, and at bend radii as small as 35 cm. Pulsed lasers are also investigated and numerical simulations indicate that optimized fibers could in principle deliver nanosecond pulses with greater than 100 mJ pulse energy over distances up to 1 km. This would be orders of magnitude higher power and longer distances than in typical machining applications using the best available solid core fibers.

A novel plasmonic sensor using solid core D-shaped negative curvature optical fiber with AU–TiO2 layer

Recently, unique structure fiber enacts a significant role in sensing applications. A novel D-shaped negative curvature fiber based surface plasmon resonance (SPR) sensor is proposed. The design consists of negative curvature solid core fiber surrounded by a cladding composed of double-layer adjoined airholes. An outside layer of the cladding contains semi-circular airholes, and the interior layer has small circular air holes to overwhelm the higher-order modes. The external sensing approach detects changes in the refractive index between 1.33 and 1.37. Employing gold as a plasmonic material, SPR is developed on top of the photonic crystal fiber (PCF). Between the gold layer and the PCF, a small layer of titanium dioxide is placed for binding the plasmonic material to the fiber. And it acts as an adhesive layer. The finite element method is used to perform numerical analyses. After improving the structural parameters, an enhanced sensitivity of 26 000 nm RIU−1 is achieved. Because of its enhanced sensitivity, this sensor is used in a bio-medical application to detect and prevent diseases in the early stage.

Fabrication of Au Nanoparticles Coated Metal Fiber for the Solid-Phase Microextraction and Determination of Lamotrigine in Complex Matrixes

A solid phase microextraction fiber (SPME) with gold nanoparticles coatings (AuNPs) was prepared based on stainless-steel fiber by chemical deposition. In order to greatly increase the specific surface area of the stainless-steel fiber, the porous fiber were formed by hydrofluoric acid treatment and aqua regia-dopamine treatment after AuNPs coating. Thus, the porous gold coated SPME with large specific surface area, strong bonding and controllable thickness were prepared. Scanning electron microscopy (SEM) and elements analysis were used to characterize. Under the optimized conditions, the prepared fibers exhibited good precision, wide linear ranges, acceptable recoveries, and low limits of detection for lamotrigine. The results verified that this novel coating was a promising sorbent for extraction and trace analysis of lamotrigine in complex matrixes.

Aniline-Naphthylamine Copolymer as the Solid Phase Microextraction (SPME) Fiber Coating for the Determination of Chlorobenzenes by Gas Chromatography – Mass Spectrometry (GC-MS)

A new solid phase microextraction fiber coating based on aniline-naphthylamine copolymer was prepared using an electrochemical approach on a wire as a robust substrate. The aniline polymer, naphthylamine polymer, and diverse ratio of the aniline-naphthylamine copolymer were synthesized and subsequently characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The results demonstrate that the aniline-naphthylamine copolymer has high porosity and a non-uniform structure compared to the unmodified polymers. The method was employed for the determination of chlorobenzenes (CBs) as model compounds for determination from water samples. The significant parameters of the sorbent morphology and extraction processes, including the type of polymer, the concentration of polymer, the electrochemical time and applied voltage, the extraction time and temperatures, and the concentration of salts, were optimized. The developed approach is sensitive, rapid, and provides suitable detection limits between 0.8 and 1.5 ng L−1. Moreover, the limit of quantification was 3–5 ng L−1 with an equilibrium time of 25 min. The linearity of the method was between 5 and 1500 ng L−1 with the correlation coefficient R2 exceeding 0.9997. The repeatability of the method was evaluated at 40 ng L−1 and relative standard deviation values were from 4 to 8% were obtained. Lastly, the developed protocol was employed to analyze natural water samples with recovery values from 96 to 101%, illustrating the absence of matrix effects.

A model for multiphase moisture and heat transport below and above the saturation point of deformable and swelling wood fibers – I: Mass transport

A thermodynamically consistent model for heat and mass transfer in deformable wood fibers is developed. The hybrid mixture theory is used to model the material as a mixture of three phases, consisting of a solid, a liquid and a gas phase. The solid phase consists of dry fibers and bound water constituents, whereas the gas phase has dry air and water vapor constituents. Emphasis is put on the mass flow and mass exchange of moisture in the material both below and above the saturation point of the solid wood fibers. Generalized forms of Fick’s, Darcy’s and Fourier’s laws are derived, and the chemical potential is used as a driving force for mass flow. Mass exchange due to sorption and evaporation/condensation processes is implemented in the model, where hysteretic properties both within and above the hygroscopic moisture range are described using Frandsen’s hysteresis model. Moisture induced swelling/shrinkage is included where the porosity of the material can vary. A large strain setting formulated for general orthotropy is adopted for the mechanical deformations. To show the performance of the resulting model, it is implemented in a finite element method framework and used to simulate the processes of heat and moisture transport dynamics of a wood sample subjected to drying from an over-hygroscopic moisture state.

Solid Fiber Inside of Capillary and Modified Fusion-Spliced Fiber Optic Microneedle Devices for Improved Light Transmission Efficiency.

Convection-enhanced delivery (CED) is a drug delivery technique used to deliver therapeutics directly to the brain and is a continually evolving technique to treat glioblastoma. Early versions of CED have proven to result in inadequate drug volume dispersed (Vd), increasing the likelihood of tumor recurrence. Fiber optic microneedle devices (FMDs) with the ability to deliver fluid and thermal energy simultaneously have shown an ability to increase Vd, but FMDs have historically had low light transmission efficiency. In this study, we present a new fabrication method, solid fiber inside capillary (SFIC) FMD, and a modified fusion splicing (FS) method with the goal of increasing light delivery efficiency. The modified FS FMD resulted in an increase in light transmission efficiency between 49% and 173% compared to previous prototypes. However, the FS FMD resulted in significantly lower transmission efficiencies compared to the SFIC FMD (p ≤ 0.04) and FS FMDs perform much worse when light-absorptive materials, like black dye, are placed in the bore. The light absorption of a candidate cytotoxic agent, QUAD-CTX, appear to be similar to water, and light delivery through FS FMDs filled with QUAD-CTX achieves a transmission efficiency of 85.6 ± 5.4%. The fabrication process of the SFIC FMDs results in extremely fragile FMDs. Therefore, the use of a modified FS FMD fabrication process appears to be better suited for balancing the desire to increase light transmission efficiency while retaining a sturdy FMD construction.

An overview of hemp for fibre market opportunities for Romania

Hemp has been cultivated by man for its multiple uses: its solid fibres for textiles, its nutritious oilseeds and the medicinal and therapeutic properties of its resin. Hemp is a technical plant that has been cultivated in Romania for over 2,000 years, its main use being to obtain fibres for making clothing. Before 1989, in Romania hemp was cultivated in large areas, exceeding 50,000 hectares, ranking 4th in the world. After 1989, interest in cultivating hemp declined, and by 2008 this crop has almost disappeared. Starting from national production capacity, this paper is presenting an overview of the textile market in Europe, with a view on the hemp market, and the marketing possibilities for Romanian hemp, based on calculations retrieved from official data available on INTRACEN and the National Institute of Statistics of Romania. The study of production capacities was analysed in terms of cultivated areas and productions obtained in Romania, reported in official national statistics. For a market projection, the data were extracted from the trade map database. The export potential was studied taking into account the harmonized standard codes for hemp.

High-strength thermal insulating porous mullite fiber-based ceramics

How to improve the strength of fibrous porous ceramics dramatically under the premise of no sacrificing its low density and thermal conductivity has remained a challenge in the high-temperature thermal insulation field. In this paper, a new kind of high-strength mullite fiber-based ceramics composed of interlocked porous mullite fibers was prepared by nanoemulsion electrospinning and dry pressing method. Results show that as to the porous ceramics with the same density (∼ 0.8 g/cm3), the three-dimensional skeleton structure composed of porous mullite fibers was much denser than that composed of solid mullite fibers. Therefore, porous mullite fiber-based ceramics exhibited a higher compressive strength (5.53 MPa) than that of solid mullite fiber-based ceramics (3.21 MPa). In addition, porous mullite fiber-based ceramics exhibited a superior high-temperature heat insulation property because the porous structure in fibers could reduce the radiant heat conduction. This work provides new insight into the development of high-temperature thermal insulators.

RADiCAL—Precision Timing, Ultracompact, Radiation-Hard Electromagnetic Calorimetry

To address the challenges of providing high-performance calorimetry in future hadron collider experiments under conditions of high luminosity and high radiation (FCC-hh environments), we conducted R&D on advanced calorimetry techniques suitable for such operation, based on scintillation and wavelength-shifting technologies and photosensor (SiPM and SiPM-like) technology. In particular, we focused our attention on ultra-compact radiation-hard EM calorimeters based on modular structures (RADiCAL modules) consisting of alternating layers of the very dense absorber and scintillating plates, read out via radiation hard wavelength shifting (WLS) solid fiber or capillary elements to photosensors positioned either proximately or remotely, depending upon their radiation tolerance. RADiCAL modules provide the capability to measure simultaneously and with high precision the position, energy and timing of EM showers. This paper provides an overview of the instrumentation and photosensor R&D associated with the RADiCAL program.

All-polarization-maintaining and high-energy fiber optical parametric chirped-pulse amplification system using a solid core photonic hybrid fiber.

We present an all-fiber optical parametric chirped-pulse amplification integrated system delivering a single-mode polarized beam. The system makes use of a specifically designed solid-core photonic hybrid fiber (i.e., combining modified total internal reflection and photonic bandgap mechanisms) that ensures sufficient birefringence to maintain the signal polarization. Moreover, the fiber combines a large mode area to handle energetic pump pulses (without generating damage or unwanted nonlinear effects) and weak dispersion to generate parametric gain bands broad enough to amplify ultrashort pulses. An efficient parametric process allows for obtaining a very high gain (>45 dB) with an output pulse energy reaching µJ range at 1053 nm by using a single 5-m hybrid fiber amplifier.

A combined molecular dynamics-finite element multiscale modeling to analyze the mechanical properties of randomly dispersed, chemisorbed carbon nanotubes/polymer nanocomposites

A two-stage molecular dynamics (MD)-finite element (FE) modeling method is developed based on the concepts of representative volume element (RVE) and equivalent solid fibers (ESFs) containing functionalized carbon nanotubes (ESFs-fCNTs). First, the influences of nanotubes’ chirality, different percent of functionalization (), various functional atoms, and polymers on the tensile and shear properties of the fCNTs inserted into the polymer matrix (fCNTs/polymer) are discovered using MD simulations. Then, using MD information as input data, the effective Young’s modulus of polymeric unit cell strengthened by ESFs-fCNTs (ESFs-fCNTs/polymer) is explored through FE modeling. The ratio of effective Young’s modulus of the unit cell () to Young’s modulus of the polymeric cube () is reported and all findings () are compared to the ESFs-pure CNTs/polymer results as well. It is found that longitudinal Young’s modulus () of nanofillers/polymer RVEs affects remarkably the of the ESFs-nanofillers/polymer nanocomposites. The decreases by increasing the Generally, the reinforcing impact of zigzag nanotubes compared to armchair ones on the of polymer RVEs is more considerable. Additionally, FE-based results illustrate that as the volume fraction of ESFs () increases, the is enhanced. At a specific the reinforcing effect of the ESFs-armchair and zigzag fCNTs is more in favor of polyethylene nanocomposites than that of the polypropylene systems.

Optical time domain backscattering of antiresonant hollow core fibers.

Today's lowest-loss hollow core fibers are based on antiresonance guidance. They have been shown both theoretically and experimentally to have very low levels of backscattering arising from the fiber structure - 45 dB below that of traditional optical fibers with a solid silica glass core. This makes their longitudinal characterization using conventional reflectometric techniques very challenging. However, it was recently estimated that when filled with air, their backscattering coefficient increases to about 30 dB below that of standard solid core fibers. This level should be measurable with commercially available high performance optical time domain reflectometers (OTDR). Here we demonstrate - for the first time to the best of our knowledge - the measurement of backscattering from the air inside a hollow core fiber. We show that the characterization of multi-km long hollow core fibers with 15 m spatial resolution is possible using a commercial OTDR instrument. To benefit from its full dynamic range, we strongly suppress the 4% back-reflections that ordinarily occur at the OTDR's standard fiber output when directly-connected to a hollow core fiber. Furthermore, low coupling loss into the hollow core fiber (0.3 dB in our experiment) also helps to maximize the achievable OTDR signal-to-noise ratio. This approach enables distributed characterization and fault-finding in low-loss hollow core fibers, a topic of increasing importance as these fibers are now starting to be installed in commercial optical communication networks.

Directly Spun Epoxy‐Crosslinked Polyethylenimine Fiber Sorbents for Direct Air Capture and Postcombustion Capture of CO2

A novel, directly‐injected solid fiber sorbent is synthesized from a solvent‐stable, epoxy‐crosslinked basic immobilized amine sorbent (BIAS) for CO2 capture. Leach resistance of the BIAS organics toward 1‐methyl‐2‐pyrrolidone/H2O (90/10, fiber solvent) reaches near 100% at the expense of CO2 capture and is achieved by increasing the extent of crosslinking. The optimized fiber sorbent, prepared with an N,N‐diglycidyl‐4‐glycidyloxyaniline/polyethylenimine (PEI)‐0.35/1 wt. ratio, retains 79.2% of PEI and captures 0.37 (direct air capture [DAC]) and 0.67 (postcombustion) mmol CO2g‐fiber−1. A nonoptimized prototype hollow fiber exhibits a stable 0.2 mmol CO2g‐fiber−1 during DAC cycling and is assembled into a ten‐fiber module. These results demonstrate a large step toward practical application of this material.

Electrospinning preparation of hollow porous Sn0.84Sm0.08Sb0.08O2 micro/nano fibers and their multispectral compatible stealth properties

SnO2 material has good stability, electrical conductivity and high visible light transmittance, showing great potential in the field of stealth materials. However, it is an important research topic that how to improve its multispectral compatible stealth performance, meet the requirements of combat weapons against all-round attack, and conform to the development trend of “thin, light-weight, wide-band and high-performance” stealth materials. Therefore, Sn0.84Sm0.08Sb0.08O2 micro/nano fibers material was prepared by coaxial electrospinning method combined with heat treatment process in this work. The material has a three-dimensional hollow porous fiber structure, and has a larger specific surface area and better compatible stealth performance than solid core fibers. The hollow porous Sn0.84Sm0.08Sb0.08O2 micro/nano fibers material shows good absorbing ability in X-band. When the matching thickness is 2.6 mm, its effective absorbing bandwidth is 3.51 GHz, and when the matching thickness is 2.8 mm, its lowest reflection loss(RL) is −22.51 dB at 10.3 GHz. Secondly, it has a lower infrared emissivity in the infrared detector working bands of 3–5 μm and 8–14 μm, which are 0.558 and 0.672, respectively. Finally, it has reflectivity at the laser operating wavelengths of 1.06 μm and 1.55 μm, which are 7.9% and 2.1%, respectively. The material achieves the organic unity of high absorption in the radar band, low emissivity in the infrared band and low reflectivity at the laser wavelength. At the same time, this work explores the regulation mechanism of the hollow porous structure on electromagnetic wave absorption, infrared emissivity and laser reflectivity, which provides a certain reference for the development of single-type, light-weight, high-performance multispectral compatible stealth materials.

Treatment of naphthenic acids in oil sands process-affected waters with a surface flow treatment wetland: mass removal, half-life, and toxicity-reduction

This study is the first to investigate the removal of naphthenic acids in a full-scale constructed wetland within the Alberta Oil Sands region. The average mass-removal efficiency for all O2-naphthenic acids measured in three separate deployments in the wetland ranged from 7.5% to 68.9% and appeared sensitive to physicochemical properties of the naphthenic acids, environmental conditions, and water quality. Treatment efficiency of individual naphthenic acids was found to increase with increasing carbon number and decreasing number of double bond equivalents in the molecule. Treatment efficiency was also found to increase with both higher initial turbidity in OSPW entering the wetland, and warmer average OSPW temperatures during wetland operation. Half-life times of naphthenic acids in the treatment wetland ranged between 8.9 and 39 days and were substantially lower than those in tailings ponds (i.e., 12.9–13.6 years) and laboratory studies focussed on bench-scale aerobic microbial biodegradation (i.e., 44–315 days). Using published dose-response data, biomimetic extraction measurements using solid phase microextraction fibers indicate that 14 days of wetland treatment resulted in a reduction in (4 d) deformity of Danio rerio from 50 to 16%, while exhibiting less than 1% toxic response for less sensitive toxic endpoints. The study concludes that wetland treatment is a feasible and productive treatment method for naphthenic acids in oil sands process-affected water due to a combination of sorption and biodegradation.