Fiber Wall Research Articles

Fiber motion in rotor spinning unit airflow: Numerical simulation and experimental validation

Airflow-assisted manufacturing holds significant promise across various applications, including rotor spinning, where airflow is crucial for fiber transfer and ultimately affects yarn performance. This study introduces a three-dimensional model of flexible fiber motion within the flow field of a rotor spinning unit. The fiber is modeled as cylindrical segments connected by rigid joints, with the segments experiencing fluid torques and the joints subjected to fluid forces. The model accounts for the fiber bending and torsional deformation. Fiber motion is determined by solving the translational and rotational equations, alongside the fiber–wall interactions. Emphasis is placed on the fiber stripping process from the opening roller. Supported by the numerical methods validated through visualization experiments and further corroborated by spinning examinations, we advance the understanding of the motion behavior of fibers released from different initial positions in the rotor spinning unit, and specifically, delve into the impact of airflow patterns on fiber movement. The developed numerical methodology and findings are vital for optimizing rotor spinning unit design and effectively harnessing airflow technology in processing.

Fiber morphological characteristics of bamboo Ferrocalamus strictus culms from different geographical distribution regions

The fiber index including fiber length, width, wall thickness and lumen diameter of Ferrocalamus strictus culms (1, 2, and ≥ 3 years) from Jinping, Mojiang and Lvchun counties of Yunnan Province was determined and the elemental content of the soil was also determined to analyze the fiber characteristics. The average relative fiber index measured for F. strictus culms were fiber length (1.30 mm), width (21.57 μm), slenderness ratio (60.79 μm), wall thickness (4.21 μm), lumen diameter (7.22 μm), and runkel ratio (1.22 μm), which belonged to the range of middle and long fibers. The fiber length increased with the culm age. The proportion of long fiber increased while short fibers decreased along with culm maturing. The fiber morphology did not show a specific trend with the culm height. Fiber length reached the maximum in the bottom portions of the culms. There is a correlation between fiber morphology and soil elements, the content of organic matter, total potassium, total sulfur, total aluminum, total zinc, total iron, total boron, alkali-hydrolyzed nitrogen and available silicon in the soil affects fiber morphology. The content of organic matter, total boron and alkali-hydrolyzed nitrogen in the soil from Mojiang County was largest. Comparatively, the culm fiber in Mojiang County had the best fiber index performance for utilization, since the greatest proportion of medium and long fibers and the optimal distribution of fiber length frequency was obtained from the culms in Mojiang County. This study can provide a theoretical basis for large-scale bamboo forest cultivation and the development and utilization of bamboo culm fiber.

Micromorphology and native extractive behaviour of wood powder

The transition to a bioeconomy is attracting the use of wood powders for developing bio-based chemicals, fuels, and products to replace fossil-based products. Wood powder-based products depend on the properties and quality of wood powders. Despite many studies on their morphological and physical properties, studies on micromorphology and extractive micro-distribution are scarce. Here we investigated the effect of milling type and wood quality in terms of moisture content on microstructural changes and native extractive distribution in wood powders. The findings showed that non-dried and dried multi-blade shaft mill (MBSM) powders had smooth surfaces and less undamaged cellulosic fibre walls, and extractives were located in the cell lumen. Non-dried and dried hammer mill powders had a rough surface and fibres with structural deformations in their cell walls (e.g. dislocations). Extractives were redistributed on the particle surface as well as dispersed in the cell lumen for both types of hammer mill powders. In a word, the powders obtained from MBSM technology are more native in structure. The findings of the study can have implications for downstream processes.

Anatomical characteristics of unproductive Elaeis guineensis stems and their correlation with density

Oil palm is Indonesia’s predominant estate crop, but it generates a significant amount of unproductive stem waste. This study examined the anatomical characteristics and their relationship with density from core to bark across the bottom, middle, and top sections, providing insights for effective OPS utilization. Anatomical characteristics were observed with optical and scanning electron microscopy, and the density was measured using an electronic densimeter. The vascular bundle numbers (VBN) increased from core to bark and decreased from top to bottom. The fiber bundle area (FBA) increased from core to bark and from top to bottom. The fiber length (FL), width (FW), and wall thickness (FWT) decreased from bottom to top, whereas the fiber lumen diameter (FLD) increased. The FL of all sections decreased from core to bark. The radial variation of FW, FLD, and FWT varied in each section. The fiber at the inner section of the middle section and the whole top section mostly showed third-grade pulp quality, whereas the bottom section and outer part of the middle section were mainly fourth-grade pulp quality. The density was positively correlated with VBN. FBA, FL, and FW were negatively correlated with oven-dry density, although not significantly, while FWT and FLD were not correlated with OPS density.

Changes in the cell wall of flax phloem fibers during gravitropic reaction

Changes in the cell wall of flax phloem fibers during gravitropic reaction

Wood properties of three south american species planted in consortium

The use of tropical wood species in reforestation can be an alternative resource to meet the demand from the industrial wood sector. However, this strategy remains very limited, even while tropical forests continue to be deliberately exploited for the selective extraction of native species of highly commercial value. To test the potential of tropical species in reforestation, it is first necessary to evaluate the production and quality of the wood produced. Therefore, this study aimed to evaluate the quality Astronium urundeuva, Astronium fraxinifolium and Terminalia argentea woods, all aged 22 years, from a heterogeneous plantation located in the municipality of Selvíria-MS. From each species, 15 trees were selected. A 10 cm thick disc was removed from the base of each tree. Samples were taken from the discs near the bark region to evaluate the anatomical characteristics and the physical and mechanical properties of the wood. According to the results, it was found that only compressive strength did not differ significantly among the species. Astronium urundeuva presented the highest values for basic density and apparent density, and Terminalia argentea presented the highest values for fiber length, fiber wall thickness and vessel element diameter. The best Pearson correlations were found for basic density and apparent density, both for Astronium fraxinifolium and Astronium urundeuva. The best regression equations obtained were correlations between basic density and apparent density for Astronium fraxinifolium and Astronium urundeuva. The linear model best fits the data for these correlations. The greater growth of Terminalia argentea trees caused lower wood density owing to the lower rate of competition among trees. Based on the results and according to wood strength standards, the three species can be classified in the D40 strength class. According to the obtained results, these can support information to be compared with some species used commercially for structural purposes and other uses.

Suitability of an ornamental tree, Sorbus alnifolia, as a source of industrial wood: Properties and the juvenile to mature transition

Ornamental trees are being promoted to supplement wood for industrial applications in China. To determine the wood utilization potential of an ornamental tree species, Sorbus alnifolia, this study investigated the radial variation of anatomical characteristics of its wood cross-section. The results showed that S. alnifolia is porous with high cell wall percentage, fiber percentage, and vessel percentage, small fiber and vessel sizes, and low vessel frequency. The transition age between juvenile wood and mature wood is 7 to 11 years for vessels, 12 to 16 years for axial parenchyma, and 18 to 24 years for fibers. Mature wood exhibits a higher percentage of cell walls, thicker fiber walls, and a lower percentage of vessels than juvenile wood. This result implies that wood is easy to dry, has strong permeability, good physical and mechanical properties, and a high fiber yield.

Identification of BpEXP family genes and functional characterization of the BpEXPA1 gene in the stems development of Betula platyphylla

Expansins (EXPs) are unique plant cell wall proteins with the ability to induce cell wall expansion and play potential roles in xylem development. In the present study, a total of 25 BpEXP genes were identified in Betula platyphylla. Results of bioinformatics analysis described that BpEXP gene family was highly conserved in the process of evolution. All these genes were clustered into four groups, EXPA (Expansin A), EXPB (Expansin B), EXLA (Expansin-like A) and EXLB (Expansin-like B), according to phylogenetic analysis and BpEXPA1 was highly homologous to PttEXP1 and PttEXP2. The results of RT-qPCR showed that BpEXPA1 was expressed higher in stems and preferentially expressed in the first internodes, followed by apical buds and the third internodes, promoter expression analysis with GUS assay demonstrated that it was expressed in developing xylem, suggesting that BpEXPA1 might be involved in the development of the primary stems of birch. Overexpression of BpEXPA1 can promote cortex cell expansion and then enlarge the cortex cell area and layer, however inhibit the secondary cell wall deposition and result in the thinner cell wall and larger lumens of xylem fiber in transgenic plants. This study will provide information for investigating the regulation mechanism of BpEXP family genes and gene resources for birch genetics improvement.

Spectrophotometric determination of o-phenylphenol in canned drinks using three-phase hollow-fiber liquid phase microextraction

A three-phase hollow-fiber liquid phase microextraction for o-phenylphenol (OPP) determination was developed. 1-octanol was employed as the organic phase, impregnated within the pores of the hollow fiber wall which was immersed in the sample solution, serving as a donor phase. OPP in the sample solution was extracted via octanol in the fiber pores into NaOH, which acted as the acceptor phase in the lumen of the fiber. The extracted OPP was then subjected to spectrophotometric detection at 712 nm using the indophenol blue reaction. The developed method showed a linear calibration curve (0.002–0.040 mg L−1) with high sensitivity (5.75 L mg−1), low limit of detection (0.31 μg L−1), and high recovery (73.6–94.8 %). Intra-day and inter-day precision at 2.1 μg L−1 OPP were 7.4 % (n = 12) and 10.9 % (n = 4) relative standard deviations, respectively. The determined OPP in various canned drinks was found to be between 2.0 and 17.8 μg L−1 using the developed method.

Boosting pH-universal electrosynthesis of hydrogen peroxide by regulating three-phase interface of carbon gas penetration electrode

Electrochemical oxygen reduction is a sustainable method for onsite H2O2 production. However, pH-universal H2O2 electrosynthesis still suffered from low kinetics and efficiency. Here carbon nanotube hollow fiber (CNT-HF) with porous fiber wall is designed to enhance H2O2 electrosynthesis via tailoring the three-phase interface. The CNT-HF gas penetration electrode with enhanced local electric field is favorable for boosting oxygen mass transfer and regulating catalyst-electrolyte interfacial protons, resulting in significantly enhanced H2O2 production performance in comparison with CNT planar gas diffusion electrode under pH-universal media. Its H2O2 production efficiency is 98.1% at pH 13. Meanwhile, H2O2 production efficiency of 96.1% and high H2O2 concentration of 46.4 g L-1 are achieved at pH 1 with 20 mM K+. Experimental and simulation results reveal the boosted H2O2 electrosynthesis on CNT-HF is mainly contributed from its significantly reduced diffusion layer thickness, enhanced local electric field and interfacial proton regulation by K+ enriched at electrode surface.

Analysis of damage evolution in single‐lap and double‐lap bolted joints of carbon fiber reinforced polymer plates based on load distribution

AbstractIt is important to study damage evolution as well as failure of carbon fiber reinforced polymer (CFRP) plates bolted joints. Therefore, the quasi‐static tensile test on single‐lap and double‐lap CFRP plates bolted joints was conducted. Meanwhile, the tensile strength prediction model for titanium alloy bolted joint of CFRP plates was established based on the improved 3D Hashin failure criterion, then a theoretical model was proposed to accurately predict the load distributions and tilt angle of bolted joints. Thus, the load–displacement curves were divided into four stages, and load distributions at different stage points as well as the relationship between tilt angle of bolt and load variation were obtained. The damage evolution of single‐lap and double‐lap at different stage points was analyzed respectively, and failure mechanisms were revealed based on load distribution. The results show that the ultimate failure of single‐lap is caused by the intrusion of bolt head into CFRP plates, while double‐lap is caused by the compression deformation of central plate. The numerical simulation works are in high agreement with the experimental results.Highlights Calculate the load distribution at single‐lap and double‐lap bolted joints. Obtain the relationship between bolts tilt angle and load variation. Analysis of damage evolution in bolt‐hole wall of carbon fiber reinforced polymer (CFRP) plates. Using loads to reveal the failure mechanisms of single‐lap and double‐lap bolted joints of CFRP plates.

Morphological and Histological Description of Spiny Dogfishshark Liver, Squalusacanthais(Linnaeus,1758),Elasmobranchii,Squaliformes

The current study describes the morphological and histological appearance of the liver of the spiny dogfish Squalusacanthais, which is classified as Class: Chondrichthyes, Subclass: Elasmobranchi. Morphologically, the liver was observed as large, and consists of two symmetrical lobes connected from the upper side, and the gallbladder was observed in the right lobe. Histologically, liver sections were prepared with H&E stain, and examined with a light microscope. Hepatic parenchyma was surrounded by a capsule of connective tissue and primarily composed of hepatocytes. The nuclei of these cells were observed at the terminal site, with lipid droplets in the cytoplasm. Central veins were observed, surrounded by connective tissue and lined with a squamous epithelial layer. Hepatocytes were, separated by numerous blood sinusoids with connective tissue. Blood arteries were observed, surrounded by thick muscular fiber walls and narrow lumens compared to veins. The portal vein was observed, along with the artery and bile duct, surrounded by a thick connective tissue. The bile duct was surrounded by a layer of muscular fibers, lined with a simple columnar epithelial layer with clear nuclei, and a connective tissue layer. Melanin-containing cells were observed, but no hepatic lobules or connective tissue were seen between them. Additionally, Hepato-pancreatic tissue was not identified.

Investigating radial gradient variations of nanostructure of cellulose microfibrils in bamboo culm by synchrotron X-ray scattering

Bamboo is a swiftly renewable natural material. A thorough exploration of its functional hierarchical structure is helpful to improve its utilization efficiency. Previous studies have found that there are notable structural distinctions in bamboo fibers and parenchyma cell wall at the nanoscale. The fluctuation in cellulose microfibrils (CMF) within bamboo has been verified as a critical factor significantly impacting the mechanical properties of bamboo fibers. This study systematically examines the radial gradient variation in the cellulose supramolecular structures of bamboo culms through synchrotron X-ray scattering. The measured cellulose crystallinity index (CrI), the diameter and packing distance of CMF, the orientation parameter, and the distribution of microfibril angle (MFA) were found to be correlated with the radial distribution of fibers and parenchyma cells. In the radial direction, the relative CrI values of 004 reflection increased from 26 % for the innermost layer to 51 % for the outermost layer; the CMF diameter decreased from 2.75 nm to 2.66 nm; the packing distance of CMF’ cylinders was reduced from 3.68 nm to 3.35 nm. The measured mean MFA values exhibit a decrease from approximately 70° to around 5°. Moreover, the azimuthal X-ray scattering signals were effectively segregated from fiber and parenchyma cell wall using the non-negative matrix factorisation (NNMF) method. This methodology holds promise for nanostructure analysis in complex plant stems comprising fiber and parenchyma cells, including but not limited to wheat, corn stalks, and other biomaterials.

Electromembrane Extraction of Ofloxacin from Human Plasma and Its Quantification by Capillary Electrophoresis

Background: Application of electromembrane extraction coupled with capillary electrophoresis was studied for ofloxacin extraction from plasma samples. Methods: Ofloxacin migrated from acidic plasma samples through a thin layer of 1-octanol immobilized in the pores of a porous hollow fiber wall into a 10 µL acidic aqueous acceptor solution located inside the lumen of the fiber. Results: Under optimum conditions influencing electromigration (i.e., 20 min of the operation time, stirring speed of 750 rpm, donor phase pH at 4.0, acceptor pH at 3.0, and applied voltage of 30 V across the supported liquid membrane), ofloxacin was extracted from plasma samples with an enrichment factor of 100-fold corresponding to extraction percent of 24%. The calibration curve showed acceptable linearity in the range of 0.2-7.0 µg.mL-1 (R=0.9993). The limits of detection and quantification of 0.05 and 0.2 µg.mL-1 were obtained, respectively. The inter- and intra-day precision and accuracy were obtained below 8.65%. Conclusion: The validated method was successfully processed for the ofloxacin determination in the plasma samples of patients under ofloxacin therapy. There were no interfering peaks which indicates the great selectivity of the developed method.

A novel semi-flexible coaxial nozzle based on fluid dynamics effects and its self-centering performance study

Coaxial nozzles are widely used to produce fibers with core–shell structures. However, conventional coaxial nozzles cannot adjust the coaxiality of the inner and outer needles in real-time during the fiber production process, resulting in uneven fiber wall thickness and poor quality. Therefore, we proposed an innovative semi-flexible coaxial nozzle with a dynamic self-centering function. This new design addresses the challenge of ensuring the coaxiality of the inner and outer needles of the coaxial nozzle. First, based on the principles of fluid dynamics and fluid–structure interaction, a self-centering model for a coaxial nozzle is established. Second, the influence of external fluid velocity and inner needle elastic modulus on the centering time and coaxiality error is analyzed by finite element simulation. Finally, the self-centering performance of the coaxial nozzle is verified by observing the coaxial extrusion process online and measuring the wall thickness of the formed hollow fiber. The results showed that the coaxiality error increased with the increase of Young’s modulus E and decreased with the increase of flow velocity. The centering time required for the inner needle to achieve force balance decreases with the increase of Young's modulus (E\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E$$\\end{document}) and fluid velocity (vf\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${v}_{f}$$\\end{document}). The nozzle exhibits significant self-centering performance, dynamically reducing the initial coaxiality error from 380 to 60 μm within 26 s. Additionally, it can mitigate the coaxiality error caused by manufacturing and assembly precision, effectively controlling them within 8 μm. Our research provides valuable references and solutions for addressing issues such as uneven fiber wall thickness caused by coaxiality errors.

Two-photon pumped random lasing in MAPbBr3 with directional output for far-field applications

We investigate the random lasing properties of polycrystalline MAPbBr3 grown in a hollow fiber. Coupling of the random lasing on the inner wall of the hollow fiber into the annular cylinder and guided by the inner surface of hollow cavity enable directional output of the random lasing emission. The polycrystalline MAPbBr3 was grown by the capillary effect, when one end of the hollow fiber was dipped into the precursor solution. A two-photon pumping scheme was employed, where femtosecond pulses centered at about 800 nm was focused onto the MAPbBr3 polycrystals through the side wall of the hollow fiber. Random lasing was achieved due to the strong optical scattering by the interfaces within the polycrystals on the inner wall of the hollow fiber. The random lasing output was re-collimated into a roughly parallel beam with a circular transverse mode, which favors far-field applications of random lasers. Two-photon pumping enables larger penetration depth and larger excitation volume than single-photon pumping, so that strong lasing spot can also be observed in the center area of the output laser beam.

Encapsulation of betacyanin extract from red dragon fruit peel with maltodextrin and inulin: Storage stability and simulated gastrointestinal digestion

Betacyanins are bioactive pigments found in red dragon fruit peels with potential health benefits, but their stability and bioaccessibility are low. This study aimed to investigate the impact of using dietary fiber inulin (IN) combined with malrodextrin (MD) as wall materials for the encapsulation of betacyanin on its physicochemical properties, storage stability, and in vitro release behavior. Different concentrations of MD and IN were tested at 30% MD + 10% IN (T1), 20% MD + 20% IN (T2), 10% MD + 30% IN (T3), and 40% MD (control). The results showed that the combination of MD and IN reduced the moisture content and water activity, increased the drying yield, and improved the hygroscopy and solubility of betacyanin extract. Furthermore, the T3 combination showed the highest encapsulation efficiency, betacyanin (BTC), phenolic content (TPC), flavonoid content (TFC), as well as antioxidant activity. FTIR analysis confirmed the effective encapsulation of betacyanin. The T1 combination exhibited the lowest degradation constant (k) and the longest stability of betacyanin storage half-life (t1/2 = 99 weeks). Additionally, the combination of MD and IN effectively improved the stability of betacyanins during simulated gastrointestinal digestion, improving the bioaccessibility of betacyanin with higher concentrations of IN (T3), resulting in the higher bioaccessibility of betacyanin (57.11%). In conclusion, this study demonstrates that the use of a combination of MD and IN as dietary fiber wall materials can improve the stability and bioaccessibility of betacyanin extract, ultimately leading to its wider utilization and potential health benefits as functional natural food colorants.

A COBRA family protein, PtrCOB3, contributes to gelatinous layer formation of tension wood fibers in poplar.

Angiosperm trees usually develop tension wood (TW) in response to gravitational stimulation. TW comprises abundant gelatinous (G-) fibers with thick G-layers primarily composed of crystalline cellulose. Understanding the pivotal factors governing G-layer formation in TW fiber remains elusive. This study elucidates the role of a Populus trichocarpa COBRA family protein, PtrCOB3, in the G-layer formation of TW fibers. PtrCOB3 expression was upregulated, and its promoter activity was enhanced during TW formation. Comparative analysis with wild-type trees revealed that ptrcob3 mutants, mediated by Cas9/gRNA gene editing, were incapable of producing G-layers within TW fibers and showed severely impaired stem lift. Fluorescence immunolabeling data revealed a dearth of crystalline cellulose in the tertiary cell wall (TCW) of ptrcob3 TW fibers. The role of PtrCOB3 in G-layer formation is contingent upon its native promoter, as evidenced by the comparative phenotypic assessments of pCOB11::PtrCOB3, pCOB3::PtrCOB3, and pCOB3::PtrCOB11 transgenic lines in the ptrcob3 background. Overexpression of PtrCOB3 under the control of its native promoter expedited G-layer formation within TW fibers. We further identified 3 transcription factors that bind to the PtrCOB3 promoter and positively regulate its transcriptional levels. Alongside the primary TCW synthesis genes, these findings enable the construction of a 2-layer transcriptional regulatory network for the G-layer formation of TW fibers. Overall, this study uncovers mechanistic insight into TW formation, whereby a specific COB protein executes the deposition of cellulose, and consequently, G-layer formation within TW fibers.

Altitude-dependent variations in some morphological and anatomical features of Anatolian chestnut

Morphological measurements of Anatolian chestnut (Castanea sativa Mill.) leaves were done within the borders of Abana district of Kastamonu province. The study was conducted using mixed (oak, beech, hornbeam, black pine, and yellow pine) medium (41% to 70%) and fully closed (71% to 100%) stands. Some leaf parameters, such as leaf blade width, petiole length, leaf blade length, leaf length, distance between lateral veins, teeth width, teeth length, the angle between the leaf base and the petiole, and the angle between the midrib and lateral veins, were measured. Moreover, stomata of the leaves picked up from precise altitudes were observed under a scanning electron microscope. The differences between fibre elevation, fibre wall thickness, elasticity coefficient, rigidity coefficient, Muhlstep rate, and Runkel ratio were found in the wood samples taken from different altitude zones. It was found that altitude did not affect leaf blade width, fibre length, fibre width, felting ratio, and lumen width. However, it was determined that altitude affected other studied characteristics.

Extracellular vesicles of Norway spruce contain precursors and enzymes for lignin formation and salicylic acid.

Lignin is a phenolic polymer in plants that rigidifies the cell walls of water-conducting tracheary elements and support-providing fibers and stone cells. Different mechanisms have been suggested for the transport of lignin precursors to the site of lignification in the cell wall. Extracellular vesicle (EV)-enriched samples isolated from a lignin-forming cell suspension culture of Norway spruce (Picea abies L. Karst.) contained both phenolic metabolites and enzymes related to lignin biosynthesis. Metabolomic analysis revealed mono-, di- and oligolignols in the EV isolates, as well as carbohydrates and amino acids. In addition, salicylic acid (SA) and some proteins involved in SA signaling were detected in the EV-enriched samples. A proteomic analysis detected several laccases, peroxidases, β-glucosidases, putative dirigent proteins, and cell wall-modifying enzymes such as glycosyl hydrolases, transglucosylase/hydrolases, and expansins in EVs. Our findings suggest that EVs are involved in transporting enzymes required for lignin polymerization in Norway spruce, and that radical coupling of monolignols can occur in these vesicles.