Interwoven Fibers Research Articles

Skin-Inspired, Highly Sensitive, Broad-Range-Response and Ultra-Strong Gradient Ionogels Prepared by Electron Beam Irradiation.

Skin, characterized by its distinctive gradient structure and interwoven fibers, possesses remarkable mechanical properties and highly sensitive attributes, enabling it to detect an extensive range of stimuli. Inspired by these inherent qualities, a pioneering approach involving the crosslinking of macromolecules through in situ electron beam irradiation (EBI) is proposed to fabricate gradient ionogels. Such a design offers remarkable mechanical properties, including excellent tensile properties (>1000%), exceptional toughness (100MJ m-3), fatigue resistance, a broad temperature range (-65-200°C), and a distinctive gradient modulus change. Moreover, the ionogel sensor exhibits an ultra-fast response time (60ms) comparable to skin, an incredibly low detection limit (1kPa), and an exceptionally wide detection range (1kPa-1MPa). The exceptional gradient ionogel material holds tremendous promise for applications in the field of smart sensors, presenting a distinct strategy for fabricating flexible gradient materials.

A direct fiber approach to model sclera collagen architecture and biomechanics

Sclera collagen fiber microstructure and mechanical behavior are central to eye physiology and pathology. They are also complex, and are therefore often studied using modeling. Most models of sclera, however, have been built within a conventional continuum framework. In this framework, collagen fibers are incorporated as statistical distributions of fiber characteristics such as the orientation of a family of fibers. The conventional continuum approach, while proven successful for describing the macroscale behavior of the sclera, does not account for the sclera fibers are long, interwoven and interact with one another. Hence, by not considering these potentially crucial characteristics, the conventional approach has only a limited ability to capture and describe sclera structure and mechanics at smaller, fiber-level, scales. Recent advances in the tools for characterizing sclera microarchitecture and mechanics bring to the forefront the need to develop more advanced modeling techniques that can incorporate and take advantage of the newly available highly detailed information. Our goal was to create a new computational modeling approach that can represent the sclera fibrous microstructure more accurately than with the conventional continuum approach, while still capturing its macroscale behavior. In this manuscript we introduce the new modeling approach, that we call direct fiber modeling, in which the collagen architecture is built explicitly by long, continuous, interwoven fibers. The fibers are embedded in a continuum matrix representing the non-fibrous tissue components. We demonstrate the approach by doing direct fiber modeling of a rectangular patch of posterior sclera. The model integrated fiber orientations obtained by polarized light microscopy from coronal and sagittal cryosections of pig and sheep. The fibers were modeled using a Mooney-Rivlin model, and the matrix using a Neo-Hookean model. The fiber parameters were determined by inversely matching experimental equi-biaxial tensile data from the literature. After reconstruction, the direct fiber model orientations agreed well with the microscopy data both in the coronal plane (adjusted R2 = 0.8234) and in the sagittal plane (adjusted R2 = 0.8495) of the sclera. With the estimated fiber properties (C10 = 5746.9 MPa; C01 = −5002.6 MPa, matrix shear modulus 200 kPa), the model's stress-strain curves simultaneously fit the experimental data in radial and circumferential directions (adjusted R2's 0.9971 and 0.9508, respectively). The estimated fiber elastic modulus at 2.16% strain was 5.45 GPa, in reasonable agreement with the literature. During stretch, the model exhibited stresses and strains at sub-fiber level, with interactions among individual fibers which are not accounted for by the conventional continuum methods. Our results demonstrate that direct fiber models can simultaneously describe the macroscale mechanics and microarchitecture of the sclera, and therefore that the approach can provide unique insight into tissue behavior questions inaccessible with continuum approaches.

Characterization of alkali-lignin-grafted polyacrylamide synthesized by atom transfer radical polymerization

The preparation of value-added, chemically modified lignin-based copolymers for the use of technical lignin is crucial for green and sustainable development. Herein, we synthesized alkali-lignin-grafted polyacrylamide by atom transfer radical polymerization (ATRP). As alkali lignin (AL) has the highest total hydroxyl group content, it was modified with 2-bromoisobutyryl bromide to synthesize a lignin macroinitiator (lignin-Br) at different ratios of [OH group in AL]:[TEA]:[BiBB] = 1:1:1, 1:1.5:1.5, and 1:2:2. Acrylamide was grafted from lignin-Br with the most Br-initiating sites via ATRP. The ratios of monomer to lignin-Br used were 50:1, 100:1, and 200:1, and the synthesized copolymers (L-g-PAM) were denoted as L-g-PAM50, L-g-PAM100, and L-g-PAM200, respectively. These copolymers were characterized by Fourier transform infrared (FT-IR) and 1H nuclear magnetic resonance (NMR) spectroscopies. The FT-IR and 1H NMR results indicated that polyacrylamide was introduced into the lignin backbone of all L-g-PAM copolymers. Gel permeation chromatography of L-g-PAM showed that the M w of L-g-PAM200 was the highest at 427,383 g/mol. Photographs and scanning electron microscopy images of L-g-PAM showed that L-g-PAM appeared as a soft sponge and contained interwoven fibers. The maximum degradation temperature (T max) of L-g-PAM increased with increasing monomer-to-lignin-Br ratio. Moreover, the glass transition temperature (T g) of L-g-PAM was higher than that of AL. The alkali-lignin-grafted polyacrylamide, synthesized by ATRP, in our study has a narrow molecular weight distribution, and its soft sponge properties make it a hydrogel or another surfactant.

Shape Memory Polymers as Lost Circulation Materials for Sealing Wide-Opened Natural Fractures

Summary While there have been various lost circulation materials (LCMs) available in the market for treating fractures during the drilling of oil and gas wells, there is still a demand for a technology to seal large fractures. Considering limitations on the size of the particles that can be circulated through the drilling equipment, especially the bottomhole assembly, simply enlarging conventional LCM particles becomes ineffective for sealing large vugs and fractures. In this study, we use shape memory polymers (SMPs) to prepare programmed LCMs with various temporary shapes, which can transform to their permanent shapes with much larger dimensions as compared to their temporary shapes. A series of steps for thermomechanical programming of SMP is designed to trigger their expansion at the reservoir temperature. The dimensions of the programmed shapes can be an order of magnitude smaller than the ones for the original shapes, making their transport through the flowlines feasible, and bridging wide-opened fractures possible. The basic idea is that, after recovery, the SMP-based LCMs form an entangled network across a large width of fracture, and SMP particles recovered within the network, filling in the pores to form an effective sealing. We seek the capability of entangled ladders and interwoven fibers in forming a network across the fracture. A permeability plugging apparatus (PPA) is used to examine the efficiency of developed LCMs. The technique of 3D X-ray computed tomography (CT) is used to visualize the internal structure of formed plugs, enabling us to understand the mechanisms of bridging, plugging, and sealing.

Eggshell-membrane-templated synthesis of C, S Doped Mesoporous NiO for methanol oxidation in alkaline solution

An interwoven hollow fiber structured mesoporous NiO catalyst doped with C, S was fabricated by the vacuum impregnation and thermal decomposition methods using eggshell membrane as template. The structure of the catalyst was characterized by X-ray diffraction, thermo-gravimetric analysis, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, and specific surface area test. Under a high vacuum condition, the synthesized NiO material has a better interwoven fiber and mesoporous structure, which effectively increases the specific surface area of the material. C and S were doped into NiO via eggshell membrane pyrolysis, which then formed C–OH and SO42− species on the surface of the material. The electrocatalytic performance of the catalyst for the oxidation of methanol in alkaline solution was studied by cyclic voltammetry and chronoamperometry. The C, S doped mesoporous NiO material exhibits much higher catalytic efficiency and anti-poisoning ability than that of NiO nanoparticles due to the synergistic catalysis of NiO and doping C–OH and SO42− species.

Morphosynthesis of SnO2 nanocrystal networks as high-capacity anodes for lithium ion batteries

Tin dioxide (SnO2) is of interest as an alternative anode material for lithium ion batteries. However, the major concern is the significant volume expansion during lithiation process, resulting in poor capacity retention and rate capability. Here, a facile morphosynthesis route is adapted for the fabrication of hierarchical SnO2 nanocrystal networks with interwoven fibers, by immersing sacrificial eggshell membrane in a Sn-based sol followed by a calcination process in air. With both structural and compositional advantages, the synthesized SnO2 networks electrode manifests superior reversible capacities of 938, 802, 736, 636, and 506 mAh g−1 even at high current densities of 0.2, 0.5, 1, 2, and 5 A g−1, respectively. Besides, its initial Coulombic efficiency (72.6%) is also much enhanced compared with that of bare SnO2 nanoparticles (59.6%) and commercial SnO2 nanopowders (46.8%). The finding highlights the probable potential application of the SnO2 networks for next-generation lithium ion batteries.

Bio-Polyamide 11 Hybrid Composites Reinforced with Basalt/Flax Interwoven Fibers: A Tough Green Composite for Semi-Structural Applications

Intraply hybrid green composites were prepared by film stacking and hot-pressing of bio-based polyamide 11 (PA11) sheets and commercial hybrid fabrics made by interweaving flax and basalt fibers (2/2 twill structure). Two matrices were considered, one of them containing a plasticizing agent. After preliminary thermal and rheological characterizations of the neat matrices, the laminates were studied in terms of flexural properties at low and high deformation rates, and the results were interpreted in the light of morphological analyses (scanning electron and optical microscopy). Despite the poor interfacial adhesion detected for all investigated composite samples, the latter exhibited a good combination of flexural strength, modulus, and impact resistance. Such well-balanced mechanical properties make the studied samples potential candidates for semi-structural applications, e.g., in the transportation sector.

Mineralogical and Geochemical Discrimination of the Occurrence and Genesis of Palygorskite in Eocene Sediments on the Northeastern Tibetan Plateau

AbstractPalygorskite is a widely used indicator of semiarid to arid environments in paleoclimate studies. In this study, we present detailed mineralogical and geochemical investigations exploring the genesis of palygorskite found in Eocene fluvial sediment in the northern Qaidam Basin on the northeastern Tibetan Plateau. The presence of two types of palygorskite is revealed, based on their crystallinity characteristics and distinctive rare earth element (REE) patterns in the coexisting clay fraction. Well‐crystallized palygorskite samples are characterized by remarkably negative Ce anomalies and obvious middle rare earth element enrichment. Poorly crystallized palygorskite samples generally exhibit positive Ce anomalies and less pronounced middle rare earth element enrichment, which resemble those of nonpalygorskite‐bearing clay samples. Given the presence of an overall oxidized fluvial sedimentary environment, we attribute the well‐crystallized palygorskite (which has textures comprising long, interwoven fibers) to direct precipitation (i.e., neoformation) occurring within a reducing environment during early/postdepositional processes while the poorly crystallized palygorskite (which is characterized by short, club‐shaped single crystals) originates as catchment‐delivered detritus. These poorly crystallized palygorskites occur mostly in 49.5–47.0 Ma and are accompanied by decreasing kaolinite content, increasing chlorite content, and abundant xerophytic spore‐pollen from the Qaidam Basin, and its neighboring Xining Basin. Collectively, these evidences suggest that a less humid climate followed after the Early Eocene Climate Optimum.

A comparative study of the properties and self-aggregation behavior of collagens from the scales and skin of grass carp (Ctenopharyngodon idella)

Collagens were extracted from the scales and skin of Ctenopharyngodon idella (C. idella) as raw materials using an acid-enzyme hybrid method. The structural properties of the extracted collagens were compared using ultraviolet-visible spectrophotometry, Fourier transform infrared spectroscopy, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and differential scanning calorimetry. Additionally, the in vitro self-aggregation behaviors of the two types of collagens (fish skin- and scale-derived collagens) were compared using turbidimetric assays, aggregation assays, and scanning electron microscopy (SEM). The results showed that both types of extracted collagen were typical type I collagen with two α chains and intact triple-helical structures. The denaturation temperatures of the collagens from fish scales and skin were 34.99°C and 39.75°C, respectively. Both types of collagens were capable of self-aggregation in neutral salt solution at 30°C, with aggregation degrees of 28% and 27.33% for the scale and skin collagens, respectively. SEM analysis revealed that both types of collagens could self-aggregate into interwoven fibers, and the fish scale-derived collagen had a more pronounced reticular fiber structure with a striped periodic D-band pattern of collagen fibrils, whereas the collagen fibers from the self-aggregation of fish skin-derived collagen had a certain degree of disruption without any D-band pattern.

Robust sacrificial polymer templates for 3D interconnected microvasculature in fiber-reinforced composites

A promising pathway for multifunctionality in fiber-composites is to mimic biological vasculature that enables living organisms with concerted homeostatic functions. In this paper, newfound material and processing advancements in vaporization of sacrificial components (VaSC), a technique for creating inverse replica architectures via thermal depolymerization of a sacrificial template, are established for enhanced vascular composites manufacturing. Sacrificial poly(lactic acid) with improved distribution of catalytic micro-particles is extruded into fibers for automated weaving and filament feedstock for 3-D printing. Fiber drawing after extrusion improves mechanical robustness for high-fidelity, composite preform weaving. Joining one-dimensional (1D) interwoven fibers with printed sacrificial (2D) templates affords three-dimensional (3D) interconnected networks in a fiber-composite laminate that inherits damage-tolerant features found in natural vasculatures. In addition to providing a conduit for enhanced functionality, the sacrificial templating techniques are compatible with current composites manufacturing processes, materials, and equipment.

3D reconstruction of elastin fibres in coronary adventitia.

A 3D reconstruction of individual fibres in vascular tissue is necessary to understand the microstructure properties of the vessel wall. The objective of this study is to determine the 3D microstructure of elastin fibres in the adventitia of coronary arteries. Quantification of fibre geometry is challenging due to the complex interwoven structure of the fibres. In particular, accurate linking of gaps remains a significant challenge, and complex features such as long gaps and interwoven fibres have not been adequately addressed by current fibre reconstruction algorithms. We use a novel line Laplacian deformation method, which better deals with fibre shape uncertainty to reconstruct elastin fibres in the coronary adventitia of five swine. A cost function, based on entropy and Euler Spiral, was used in the shortest path search.We find that mean diameter of elastin fibres is 1.67 ± 1.42 μm and fibre orientation is clustered around two major angles of 8.9˚ and 81.8˚. Comparing with CT-FIRE, we find that our method gives more accurate estimation of fibre width. To our knowledge, the measurements obtained using our algorithm represent the first investigation focused on the reconstruction of full elastin fibre length. Our data provide a foundation for a 3D microstructural model of the coronary adventitia to elucidate the structure-function relationship of elastin fibres.

A modular self-assembly approach to functionalised β-sheet peptide hydrogel biomaterials.

Two complementary β-sheet-forming decapeptides have been created that form binary self-repairing hydrogels upon combination of the respective free-flowing peptide solutions at pH 7 and >0.28 wt%. The component peptides showed little structure separately but formed extended β-sheet fibres upon mixing, which became entangled to produce stiff hydrogels. Microscopy revealed two major structures; thin fibrils with a twisted or helical appearance and with widths comparable to the predicted lengths of the peptides within a β-sheet, and thicker, longer, interwoven fibres that appear to comprise laterally-packed fibrils. A range of gel stiffnesses (G' from 0.05 to 100 kPa) could be attained in this system by altering the assembly conditions, stiffnesses that cover the rheological properties desirable for cell culture scaffolds. Doping in a RGD-tagged component peptide at 5 mol% improved 3T3 fibroblast attachment and viability compared to hydrogel fibres without RGD functionalisation.

PH triggered self-assembly induced enhanced emission of phosphonic acid appended naphthalenediimide amphiphile

pH triggered self-assembly induced enhanced emission of water soluble phosphonic acid–NDI amphiphiles 1 is described. At pH 4.5, the amphiphile self-assembled into interwoven fibres, whilst a ladder-type network was observed at pH 7. At pH 9.5, NDI amphiphile assembled into more complex fractal nanostructures. Interestingly, enhancement of emission was observed under both acidic and basic conditions.

Rotated Hough filtering for automatically distinguishing the collagen bundles in the most superficial layer of articular cartilage.

The structure of the collagen matrix in the most superficial layer of articular cartilage (AC) is particularly critical to the wear and tensile resistance of AC. Disruption of the collagen network leads to rapid wear of the articular surface, which is a major contributory factor of osteoarthritis. Interwoven fiber bundles have been observed in the most superficial layer of healthy AC under confocal microscopy, but gradually disappear with age and pathological change of AC. The image analysis techniques developed in this paper aimed to provide a quantitative description of the relationship between the presence of the fiber bundles in the lamina splendens and health status of AC. The result of this quantitative study confirmed the existence of fiber bundles in healthy AC, and the accuracy of the identified fiber bundles was up to 90%. With the development of confocal arthroscopy for imaging microstructure of AC without biopsy, the image analysis technique can aid to efficiently assess the physiological status of AC for orthopedic clinics.

Macro and Micro Investigation of Internal Structure of Filament Wound Composite

Abstract: The characteristic of internal structure of filament wound composite is investigated by experiment in this article. Cylinders manufactured by two kinds of fiber, E-glass and carbon, and epoxy resin, are cut into several pieces along the winding direction. The sections of pieces are observed with optic microscope. The result shows that there are two kinds of structure in filament wound composite, laminate area and undulating area, consisting of interwoven fiber band in different directions. Undulating quantity is measured at a series of points along undulating fiber band; a linear model is adopted to model geometrical shape of undulation.

Dolocretes and Associated Palygorskite Occurrences in Siliciclastic Red Mudstones of the Sariyer Formation (Middle Miocene), Southeastern Side of the Çanakkale Strait, Turkey

AbstractThe origins of dolocrete and associated palygorskite in the Çanakkale region of Turkey have been little studied, but are of fundamental importance for a more complete understanding of the mineralogy of this region. The present study was undertaken in order to narrow this gap. Siliciclastic red mudstones within alluvial-fan deposits of the Middle Miocene Sariyer Formation locally contain dolocretes in various forms (powdery, nodular, and fracture-filling) and scarce matte-brown, authigenic clay lenses. The mineralogical characteristics of dolocrete and authigenic clay lenses were examined using polarized-light microscopy, X-ray diffraction, differential thermal analysis and thermal gravimetry, scanning-electron microscopy, and infrared spectroscopy, as well as by chemical and isotopic methods. These analyses indicate that the dolocretes are indeed predominantly dolomite, coexisting with variable amounts of palygorskite. The authigenic clay lenses are composed mainly of palygorskite. Dolomite appears as euhedral crystals, whereas palygorskite developed authigenically as interwoven fibers on and between resorbed dolomite crystals, rimming euhedral crystals, and as fiber bundles (where dolomite ± magnesite is absent). The stable-isotope values and some petrographic features, such as alveolar texture and dolomite needles, support a pedogenic origin for the dolocretes. In the initial stage, dolomite formed by replacement of siliciclastic red mudstones and/or by precipitation from percolating soil-derived water in a near-surface setting. Subsequently, palygorskite either precipitated on the dolomite crystals from relatively more evaporative water, replaced the host-rock mudstone in the presence of Al + Fe, or formed directly from solution where the Ca/Mg ratio decreased and the Al + Fe increased. In view of the large Cr and Ni contents of the bulk-rock samples, the elements required for the crystallization of dolomite and palygorskite (namely Mg, Ca, Si, Al, and Fe) may have been supplied by weathering of ophiolitic rocks that crop out in the area.

The Geology and Origin of Sepiolite, Palygorskite and Saponite in Neogene Lacustrine Sediments of the Serinhisar-Acipayam Basin, Denizli, SW Turkey

AbstractThe Serinhisar-Acıpayam basin of western Anatolia hosts a Neogene alkaline lake which formed in some graben and semi-graben depression zones as a result of N–S tension. The basin is filled with fluvial and lacustrine sediments dominated by clayey materials. The filling of the basin with fine sediments and associated water level changes caused the development of swampy and/or semi-swampy, alkaline-lake environments where sepiolite, palygorskite, saponite and dolomitic sepiolite or palygorskite precipitated periodically in the basin. Sepiolite is predominant in the Kuyucak section and is intercalated with saponite-dominated levels, whereas saponite accompanied palygorskite at Kocapınar where basaltic volcanism occurred. The contacts between sepiolite-palygorskite and saponite levels are more or less sharp, reflecting rapid changes in the physicochemical conditions of the depositional environment. Micromorphological images reveal that both sepiolite and palygorskite grew as interwoven fibers or fiber bundles and masses where dolomite was absent, indicating direct precipitation from solution, whereas fibrous networks grew authigenically on and out of dolomite in dolomitic sepiolite and dolomitic palygorskite. Saponite is either green or reddish brown due to its organic material-rich content and derivation from products of basaltic volcanism. Synsedimentary basaltic volcanism was the main source of Fe and Al, whereas Si and Mg were derived from surrounding ultrabasic and detrital units and partly from the volcanism. It can be concluded that sepiolite, palygorskite and saponite formed either by direct precipitation from alkaline lake water or authigenically from interstitial pore-water between dolomite rhombs as controlled by concentration of Si, Mg, Al and Fe, rather than by mutual transformation.

Plaque-like structures and arteriosclerotic changes in "diffuse neurofibrillary tangles with calcification" (DNTC).

"Diffuse neurofibrillary tangles with calcification" (DNTC) is a rare form of slowly progressive dementia characterized by temporal or fronto-temporal atrophy with neuronal loss and astrocytosis, neurofibrillary tangles and Fahr-type calcification, but no senile plaques in the cerebral cortex. In patients with DNTC, we detected a novel histopathological abnormality that we termed "plaque-like structures" (PLS). PLS appeared as oval, slightly eosinophilic masses of up to 100 microns in diameter. With methenamine silver stain, the PLS were argyrophilic, and thread-like structures were observed in and around them. Most PLS were observed in deep layers of the cortex and subcortical white matter, and were accompanied by small vessels. They were intimately associated with the small-vessel walls and astrocytes. They were composed of two types of fibers. The first type comprised straight and loosely interwoven fibers about 25-30 nm in diameter, while the other type evoked tangles. These structures have not been found in other neurodegenerative diseases, including Alzheimer's disease. In addition, to evaluate hyaline arteriosclerosis in DNTC, we examined sclerotic changes of the medullary arteries and assessed white matter lesions in affected patients. In three of four patients with DNTC, sclerosis of the medullary arteries was significantly more extensive than in age-matched controls. In all four patients, the severity of white matter lesions was graded as moderate or severe in the temporal lobe and as mild or moderate in the frontal lobe. Arteriosclerotic changes and white matter lesions can occur without hypertension and beta amyloid deposits in DNTC.

Quantitative recovery of virus from blood plasma using a polycarbonate filter purification procedure

Polycarbonate filters (Nuclepore Corporation, Pleasanton, CA) have beep used for sizing particulates such as virus particles and liposomes. Unlike nitrocellulose, polyester and other types of filters which are comprised of a relatively thick meshwork of interwoven fibers, polycarbonate filters are thin and contain precisely sized, straight-bore holes (Fig. 1). These features suggest that loss of particles due to nonspecific adsorption or entrapment in the filter matrix might be less for polycarbonate filters. In the present study, we have devised a purification technique based on the sequential filtration of blood plasma through a series of polycarbonate filters. The technique was evaluated by seeding chimpanzee blood plasma with human rotavirus (65-70 nm dia.) and determining recovery of purified virus using a sensitive electron microscope virus particle counting technique.Whole normal blood plasma (10 ml) was seeded with highly purified rotavirus to a final concentration of about 1010 particles per ml.

Transition flow of a fibrous suspension in a pipe as the flow of an anisotropic fluid

The transition flow is considered of a fibrous suspension in a pipe. The flow region consists of two subregions: at the center of the flow a plug formed by interwoven fibers and fluid moves as a rigid body; between the solid wall and the plug is a boundary layer in which the suspension is a mixture of the liquid phase and fibers separated from the plug [1–3]. In the boundary region the suspension is simulated as an anisotropic Ericksen—Leslie fluid [4, 5] which satisfies certain additional conditions. Equations are obtained for the velocity profile and drag coefficient of the pipe, which are both qualitatively and quantitatively in good agreement with the experimental results [6–8]. Within the framework of the model, a mechanism is found for reducing the drag in the flow of a fibrous suspension as compared to the drag of its liquid phase.