Fiber Bundle Diameter Research Articles

Experimental and Statistical Investigations for Tensile Properties of Hemp Fibers

This study investigated the tensile behaviors of hemp fiber bundles and examined how properties including tensile strength and Young’s modulus vary with the bundle diameter. Hemp fibers were extracted, degummed, and separated into bundles of different diameters ranging from less than 50 μm to over 150 μm. Tensile tests were conducted on these fiber bundles using a rheometer-based tensile testing machine. The results showed that hemp fibers exhibited a tensile strength of 97.33 MPa and a Young’s modulus of 3.77 GPa at a 50% survival probability. However, the scale parameters for breaking stress and Young’s modulus were determined to be 620.57 MPa and 29.88 GPa, respectively. As the fiber bundle diameter increased, the tensile strength decreased significantly. This was attributed to the higher probability of defects and irregularities acting as weakness points in larger fiber bundles. In contrast, Young’s modulus (stiffness) increased with increasing bundle diameter, likely due to improved fiber–fiber interactions. To further understand the variability and reliability of the tensile properties, statistical models were developed. The Weibull distribution analysis was applied, revealing critical insights into the variability of diameter, stress at break, Young’s modulus, and strain at break. The Weibull parameters provided a comprehensive understanding of the fibers’ mechanical reliability. Additionally, the Griffith model was employed to predict the strength and Young’s modulus based on fiber diameters, supporting the observation that thinner fibers generally exhibited higher tensile strength due to fewer defects. Overall, this work highlights the importance of understanding structure–property relationships in natural fibers like hemp for optimizing their performance in composites.

Effect of extension speed on the mechanical performance of sisal and coir fiber bundles

Quasi-static tensile tests are commonly used to determine the mechanical properties of fiber bundles. These tests are generally carried out at a low standard speed of 1 mm.min−1, which is recommended for elementary fibers, although other moderate and high speeds are rarely used. In this study, tensile tests were carried out on coir and sisal fiber bundles from the coastal region of Cameroon using four different speeds: 1, 2, 5, and 10 mm.min−1 to assess mechanical properties. Samples were prepared by attaching the two ends of each randomly selected fiber bundle to a paper frame to obtain a length of 30 mm. The results showed a significant effect of extension speed, indicating a decrease in tensile strength and Young’s modulus, and an increase in strain at break with increasing speed. These trends were correlated with the power functions. A strong dependence between fiber bundle diameter and tensile strength was also observed. Furthermore, statistical analysis based on the Weibull distribution highlighted the dispersion of mechanical properties, demonstrating a reduction in dispersion with increasing extension speed for coir fibers. These data can be used to develop specific standards for these natural fibers and contribute to the advancement of composites based on plant fibers.

Alveolar Bone Microstructure Surrounding Orthodontic Anchor Screws with Plasma Surface Treatment in Rats.

A lateral load was applied to anchor screws that had undergone surface treatment, and the structure, cellular dynamics, and quality of the bone surrounding anchor screws were analyzed to investigate the effect of this surface treatment on the peri-implant jawbone. In addition, bone microstructural characteristics were quantitatively evaluated for each site of loading on the bone around the anchor screw. Rats were euthanized after observation on days 3, 5, or 7, and bone quality analyses were performed. Bone-implant contact rate increased more rapidly at an early stage in the treated surface group than in the untreated surface group. Bone lacuna morphometry showed that the measured values adjacent to the screw at the screw neck on the compressed side (A) and at the screw tip on the uncompressed side (D) were significantly lower than those at the screw tip on the compressed side (B) and at the screw neck on the uncompressed side (C). Collagen fiber bundle diameter showed that the measured values adjacent to regions A and D were significantly higher than those at regions B and C. Anchor screw surface activation facilitates initial bone contact of the screw, suggesting that early loading may be possible in clinical practice.

Age-Related Properties of Aquaponics-Derived Tilapia Skin (Oreochromis niloticus): A Structural and Compositional Study.

In the last two decades, fisheries and fish industries by-products have started to be recovered for the extraction of type I collagen because of issues related to the extraction of traditional mammalian tissues. In this work, special attention has been paid to by-products from fish bred in aquaponic plants. The valorization of aquaponic fish wastes as sources of biopolymers would make the derived materials eco-friendlier and attractive in terms of profitability and cost effectiveness. Among fish species, Nile Tilapia is the second-most farmed species in the world and its skin is commonly chosen as a collagen extraction source. However, to the best of our knowledge, no studies have been carried out to investigate, in depth, the age-related differences in fish skin with the final aim of selecting the most advantageous fish size for collagen extraction. In this work, the impact of age on the structural and compositional properties of Tilapia skin was evaluated with the aim of selecting the condition that best lends itself to the extraction of type I collagen for biomedical applications, based on the known fact that the properties of the original tissue have a significant impact on those of the final product. Performed analysis showed statistically significant age-related differences. In particular, an increase in skin thickness (+110 µm) and of wavy-like collagen fiber bundle diameter (+3 µm) besides their organization variation was observed with age. Additionally, a preferred collagen molecule orientation along two specific directions was revealed, with a higher fiber orientation degree according to age. Thermal analysis registered a shift of the endothermic peak (+1.7 °C) and an increase in the enthalpy (+3.3 J/g), while mechanical properties were found to be anisotropic, with an age-dependent brittle behavior. Water (+13%) and ash (+0.6%) contents were found to be directly proportional with age, as opposed to protein (-8%) and lipid (-10%) contents. The amino acid composition revealed a decrease in the valine, leucine, isoleucine, and threonine content and an increase in proline and hydroxyproline. Lastly, fatty acids C14:0, C15:0, C16:1, C18:2n6c, C18:3n6, C18:0, C20:3n3, and C23:0 were revealed to be upregulated, while C18:1n9c was downregulated with age.

Effect of Different Conditions of Sodium Chloride Treatment on the Characteristics of Kenaf Fiber Bundles

Currently, composite board manufacturing using natural fibers has the potential to expand owing to environmental awareness. To produce a composite board, treatment is required to improve the mechanical and physical properties of the natural fibers. In this study, sodium chloride (NaCl) was used for the chemical treatment. However, studies on chemical treatments using NaCl are limited. This study aimed to investigate the characteristics of kenaf fibers after NaCl treatment. The NaCl treatment concentrations were 1, 3, and 5 wt.% at room temperature, with soaking durations of 1, 2, and 3 h. The tensile strength, strain, and Young’s modulus were measured to evaluate the mechanical properties of the fibers. The fiber bundle diameter, weight change owing to treatment, and contact angle were determined to analyze the effect of NaCl treatment. The kenaf fiber bundle treated with 5 wt.% NaCl for 3 h exhibited the highest tensile strength, Young’s modulus, reduction in fiber bundle diameter, weight change, and decrease in contact angle compared to those of untreated fiber bundles. The tensile properties of the fiber bundle exhibited a tendency to decrease with increasing fiber bundle diameter. Increasing the soaking duration from 1 to 2 h did not result in a significant decrease in the fiber bundle diameter or an increase in tensile strength. However, a further increase in the soaking duration from 2 to 3 h resulted in a considerable decrease in the fiber bundle diameter and an increase in the tensile strength.

Experimental Investigation on Fracture Performance of Short Basalt Fiber Bundle Reinforced Concrete

In this paper, a notched three-point bending test is used to study the fracture performance of the short basalt fiber bundle reinforced concrete (SBFBRC). To compare and analyze the enhancement effect of different diameters and different content of basalt fiber bundles on the fracture performance of concrete, some groups are set up, and the P-CMOD curves of each group of specimens are measured, and the fracture toughness and fracture energy of each control group are calculated. The fracture toughness and fracture energy are two important fracture performance parameters to study the effect and law of the new basalt fiber bundles on the fracture performance of concrete. The research results show that the diameter and content of the new basalt fiber bundles have a certain effect on the fracture performance of concrete. With the increase of the content of basalt fiber bundles, the peak load, crack initiation toughness, instability toughness and fracture energy of SBFBRC are greatly improved compared with the benchmark group. When the fiber bundle diameter is 0.2 mm, the peak load increases by 69.5% compared with the reference group. The instability toughness reaches its maximum value at 0.2 mm diameter, which is 59.7% higher than the benchmark.

Three-dimensional numerical study of the directional heat transfer in an L-shaped carbon/carbon composite thermal protection system

Designing an accurate and efficient heat protection system for the area around the high-temperature stagnation point on supersonic aircraft is still an important topic of research. In the present study, a three-dimensional high thermal conductivity carbon/carbon (C/C) composite thermal protection system embedded with L-shaped carbon fiber bundles for directional heat transfer is proposed as a high-efficiency thermal protection design. A multi-scale method, which couples the finite volume method (FVM) and lattice Boltzmann method (LBM), is developed to investigate the directional heat transfer in the proposed structure. The FVM is used to calculate the heat radiation information, which is needed to solve the energy equation with the LBM. Further, the failure temperature of the proposed thermal protection structure is defined. The effects of the porosity, carbon fiber bundle and pore diameter on the directional heat transfer of the L-shaped C/C composite thermal protection system are investigated in detail. The results show that the effective thermal conductivity of the proposed thermal protection system increases with increasing temperature and carbon fiber bundle diameter. It decreases with increasing porosity when the temperature is below 1000 °C. There exists the competitive relationship between the pore heat radiation and carbon fiber bundle thermal conductivity. An increased porosity results in a decrease in the failure temperature of the proposed thermal protection structure, while increasing the carbon fiber bundle diameter can increase the failure temperature. These findings can provide some new insights for designing a high-performance C/C composite thermal protection system.

Machinability of wood fiber/polyethylene composite during orthogonal cutting

Wood fiber/polyethylene composite (WFPEC) is composed of a natural wood fiber and a recyclable polyethylene plastic, which is normally used as an environmental protection composite material. However, better knowledge of chip formation and surface damage mechanism of WFPEC is essential to improve its machinability for extending exterior and interior applications. In this article, machinability of WFPEC was investigated by analyzing the disparity between cutting efficiency and surface quality through a group of orthogonal cutting experiments with change of cutting depth. The chip formation process was recorded by a high-speed camera system with 5000 frames per second. Surface topography was observed by a scanning electron microscope. The results showed that the chip morphology changed from continuous cutting governed by a continuous shearing process under the shallow cutting depth, to a discontinuous cutting governed by plastic fracture under the deep cutting depth ahead of the tool tip. Flattened matrix was the main form of surface topography caused by shallow cutting depth, while matrix-fiber tearing was caused by deep cutting depth. Pullout/fracture and debonding of fibers were related to the fiber orientation angle and the diameter of fiber bundles, but not to the cutting depth. Taken together, the toughness of the workpiece material in the cutting region decreased with the increase in cutting depth. To avoid matrix-fiber tearing, shallow cutting depth should be used during finishing to maintain surface quality. In contrast, pre-cutting can be performed with a deep cutting depth in order to improve the cutting efficiency.

CSF contamination-invariant statistics in conventional diffusion-weighted MRI of the fornix

The goal of this paper is to develop a method for assessment of microstructural properties of the fornix in conventional (low resolution, single non-zero b-value) diffusion-weighted magnetic resonance imaging (DW-MRI) data. For this purpose, a bi-tensor model, comprising of an isotropic and an anisotropic diffusion compartment, was fitted to the diffusion-weighted images. Two subject-specific constraints were studied to solve the ill-posedness of the parameter estimation at a single (non-zero) b-value, namely by fixating the mean diffusivity (MD) or the axial diffusivity (AxD) of the anisotropic compartment. The bi-tensor statistics were compared to conventional diffusion statistics using simulated fiber bundles with different diameters and using fornix segmentations of 577 elderly subjects. Based on simulated fiber bundles, the anisotropy (FA) estimated by the bi-tensor model did not become biased with decreasing fiber bundle diameter, unlike conventional diffusion statistics such as FA and MD estimated by the single tensor model. In the population-based study, the bi-tensor tissue fraction decreased significantly with age, suggesting an increase of free water. The FA estimated by the bi-tensor model decreased with age, but this relation was not significant when the subject-specific values to which MD or AxD were constrained were added as covariates in the regression analysis. The distinction of an isotropic and an anisotropic diffusion compartment may allow a more sophisticated analysis of the fornix based on conventional DW-MRI data.

Fiber Bundle Design for an Integrated Wearable Artificial Lung.

Mechanical ventilation (MV) and extracorporeal membrane oxygenation (ECMO) are the only viable treatment options for lung failure patients at the end-stage, including acute respiratory distress syndrome (ARDS) and chronic obstructive pulmonary disease (COPD). These treatments, however, are associated with high morbidity and mortality because of long wait times for lung transplant. Contemporary clinical literature has shown ambulation improves post-transplant outcomes in lung failure patients. Given this, we are developing the Pittsburgh Ambulatory Assist Lung (PAAL), a truly wearable artificial lung that allows for ambulation. In this study, we targeted 180 ml/min oxygenation and determined the form factor for a hollow fiber membrane (HFM) bundle for the PAAL. Based on a previously published mass transfer correlation, we modeled oxygenation efficiency as a function of fiber bundle diameter. Three benchmark fiber bundles were fabricated to validate the model through in vitro blood gas exchange at blood flow rates from 1 to 4 L/min according to ASTM standards. We used the model to determine a final design, which was characterized in vitro through a gas exchange as well as a hemolysis study at 3.5 L/min. The percent difference between model predictions and experiment for the benchmark bundles ranged from 3% to 17.5% at the flow rates tested. Using the model, we predicted a 1.75 in diameter bundle with 0.65 m surface area would produce 180 ml/min at 3.5 L/min blood flow rate. The oxygenation efficiency was 278 ml/min/m and the Normalized Index of Hemolysis (NIH) was less than 0.05 g/100 L. Future work involves integrating this bundle into the PAAL for which an experimental prototype is under development in our laboratory.

Fold-Resistant Characteristics of the Laminate Composites for Flexible Structure

There is considerable interest in the use of flexible laminate composite materials to improve the deployable structures for space applications. Critical to acceptance of these materials is the ability to achieve high packaging strains without damage. However, there does exist more or less damage during the process of folding and unfolding for the laminate composites. Better understanding of folding damage, therefore, is needed for the design of laminate composites and folding pattern. In this work we present a study on the fold-resistant characteristics of two different laminate composites, which were fabricated by covering the aramid fiber/epoxy and carbon fiber/epoxy prepregs respectively with polyimide film on both sides. The results of tensile tests on 3-layer structure laminate composites show that the fold-resistant properties of aramid fiber/epoxy composites could be improved with increasing of the resin content and decreasing of the fiber bundle diameter. For carbon fiber/epoxy composites, the effects of resin content and fiber bundle diameter on reduction rate of fracture strength were more complex. There existed a best range of resin content and fiber bundle diameter. The microscopic observations show that folding resulted in piling up of resin and damage of reinforcing fiber, which would decrease the mechanical properties.

Tensile strength of windmill palm (Trachycarpus fortunei) fiber bundles and its structural implications

Trachycarpus fortunei (windmill palm) is one of the most widely distributed and widely used palms in East Asia. In order to find further uses for the palm’s fibers, however, more information on their mechanical and anatomical properties is needed. With this in mind, tensile strength and Young’s modulus of windmill palm fiber bundles were investigated and the structural implications considered. The anatomical features in cross-section, the fracture mode, and the microfibril angle (MFA) of natural fiber bundles were determined. The transverse sectional area occupied by fibers in a fiber bundles (SF) contributes to mechanical strength in practice. It was found that the ratio of SF to the transverse sectional area of a fiber bundle dramatically increases with a decrease in bundle diameter. Therefore, tensile strength and Young’s modulus of an individual fiber bundle in this species increase in parallel with a decrease in fiber bundle diameter. The observed MFA features might have a relationship with the biomechanical movements of fiber bundles in the windmill palm. The potential uses of windmill palm fibers have been discussed.

Caracteres anatômicos de fibras foliares de brotações de curauá propagadas <em>in vitro</em>

Curaua [ Ananas erectifolius (L.B.Sm) - Bromeliaceae] is a species with great utilization potential in the car manufacture, due to its resistance, softness and reduced weight. The objective of this study was to examine the presence of fibers in curaua plantlet cultured in vitro deriving or not from elongation as well as to contribute to anatomical leaf description. curaua shoots produced in vitro were compared, by the conventional method (T1) and by the elongation method (T2). In the transversal cuts, fibers bundle related or not to the nervure were counted and fiber bundle diameters measured. The number and fiber bundle diameter related or not to vein were superior in (T1) that produced 23.7 fibers not related to vein while (T2) produced 14.3. The related fibers to vein (T1) produced 14.6 and (T2) 11.3. As for fibers diameter related to vein (T1) obtained 61.61 μm and (T2) 53.17 μm. For the fibers diameter not related to vein, there was no significant difference. For anatomical characteristics, higher visual differences are in the chlorenchyma volume and in the aquiferus parenchyma that were higher in (T2). Therefore, curaua’s shootlet cultured in vitro from shoot elongation tend to produce more fibers.

An electrospun triphasic nanofibrous scaffold for bone tissue engineering

A nanofibrous triphasic scaffold was electrospun from a mixture of polycaprolactone (PCL), type-I collagen and hydroxyapatite nanoparticles (nano-HA) with a mixture dry weight ratio of 50/30/20, respectively. Scaffolds were characterized by evaluating fiber morphology and chemical composition, dispersion of HA particles and nanoindentation. Scanning electron microscopy revealed fibers with an average diameter of 180 ± 50 nm, which coincides well with the collagen fiber bundle diameter characteristic of the native extracellular matrix of bone. The triphasic fibers, stained with calcein and imaged with confocal microscopy, show a uniform dispersion of apatite particles throughout their length with minor agglomeration. Scaffold fibers of triphasic (50/30/20), collagen/nano-HA (80/20), PCL/nano-HA (80/20), pure PCL and pure collagen were each pressure consolidated into non-porous pellets for evaluation by transmission electron microscopy and nanoindentation. While the majority of apatite particles are uniformly dispersed having an average size of 30 nm, agglomerated particles as large as a few microns are sparsely distributed. Nanoindentation of the pressure-consolidated scaffolds showed a range of Young's modulus (0.50–3.9 GPa), with increasing average modulus in the order of (PCL < PCL/nano-HA < collagen < triphasic < collagen/nano-HA). The modulus data emphasize the importance of collagen and its interaction with other components in affecting mechanical properties of osteoconductive scaffolds.

Characterization of the morphological, physical, and mechanical properties of seven nonwood plant fiber bundles

The morphological, physical, and mechanical properties of the nonwood plant fiber bundles of ramie, pineapple, sansevieria, kenaf, abaca, sisal, and coconut fiber bundles were investigated. All fibers except those of coconut fiber had noncircular cross-sectional shapes. The crosssectional area of the fiber bundles was evaluated by an improved method using scanning electron microscope images. The coefficient factor defined as the ratio of the cross-sectional area determined by diameter measurement, to the cross-sectional area determined by image analysis was between 0.92 and 0.96 for all fibers. This indicated that the area determined by diameter measurement was available. The densities of the fiber bundles decreased with increasing diameters. The diameters of each fiber species had small variation of around 3.4%-9.8% within a specimen. The tensile strength and Young’s modulus of ramie, pineapple, and sansevieria fiber bundles showed excellent values in comparison with the other fibers. The tensile strength and Young’s modulus showed a decreasing trend with increasing diameter of fiber bundles.

Presbycusic Neuritic Degeneration Within the Osseous Spiral Lamina

To describe a neglected anatomic variant occurring with presbycusis. Retrospective temporal bone histopathology study. Quantitative analysis of peripheral hair cells, neurites, neurons, and the stria vascularis in temporal bones from individuals who had presbycusis. Fifty-three patients aged 65 years or older and with a down-sloping audiogram and clinical diagnosis of presbycusis were reviewed. Nine cases had normal hair and ganglion cell populations but reduced peripheral processes (neuritic presbycusis). These were compared with five normal-hearing controls on measurements of anterior middle and basal turn fiber bundle diameter and the ratio of basal to middle diameters. Thresholds at 4 and 8 kHz were significantly poorer in the neuritic presbycusis group than in the control group (p<or=0.004 and 0.05, respectively), as was speech discrimination score (p<or=0.028). The ratio of basal to middle turn diameters was significantly smaller in the neuritic presbycusis group (p<or=0.003). This effect was quite marked in that there was no overlap in ratios between the groups, with the maximum neuritic presbycusis group ratio smaller than the minimum control group ratio. There was a moderate negative correlation between ratio and threshold at 4 kHz (sigma=-0.49, p<or=0.075). Loss of peripheral neurites in the anterior basal cochlear segment is found in conjunction with presbycusis in temporal bones that have no other morphologic abnormalities. These cases can be identified by a gradual down-sloping audiogram in contrast to sensory (hair cell) presbycusis, which is characterized by a precipitous high tone loss.

Effect of Surface Treatment on Interfacial Strength between Bamboo Fiber and PP Resin

The interfacial shear strength (IFSS) between a bamboo fiber bundle and maleic anhydride polypropylene (MAPP) was examined for various kinds of surface treatments in conjunction with ultrasonic washing. Bamboo fiber bundles were extracted from Chinese bamboo by either mechanical scratching or steam explosion. The effect of fiber bundle diameter on IFSS was measured by using the micro-droplet test. The test results showed that higher IFSS was observed for bundles having smaller diameter. Isocyanate silane treatment improved IFSS in the case of raw bamboo fibers while it was less effective to improve IFSS for steam exploded fibers. The highest tensile strength of bamboo fiber reinforced polypropylene was obtained when steam exploded bamboo fibers were used as the reinforcement.

Analysis of Roofing Mat Structure

We describe hardware and software features of an image analysis-based instrument developed in our laboratory to characterize web structure. The potential value of detailed web analysis that is possible today using image analysis is illustrated for a small number of roofing mat webs by characterizing basis weight (small area) uniformity, fiber bundle orientation (directionality control) and fiber bundle diameter (dispersion quality). From this analysis, we show that it is possible to observe differences in web structure between the top and wire sides of webs, built-up roofing and shingle mat webs, production with hydraulic pressurized (closed) and atmospheric (open) headboxes, production with and without a flow synchronizer, and web basis weight.

Notched Strength of Thermoplastic Woven Fabric Composites

Woven fabric composites with a thermoplastic matrix form a class of promising materials for industrial use, due to their balance of properties. They combine excellent mechanical performance with ease of processing. Failure behavior of notched woven fabric composites shows a number of peculiarities, the most notorious being the dependence of notched tensile strength on notch radius below a certain hole size. This dependence, which is observed for all fiber reinforced composites, has been modelled by other authors with the aid of semi-empirical continuum mechanics models. If at all based on physical principles, the modelled fracture process rarely coincides with experimentally observed failure phenomena. This study investigates failure of notched woven fabric (0-90)4, E-glass laminates with a PETP matrix. A model is proposed which is, unlike other previous modelling efforts, related to experimentally observed fracture phenomena. It introduces the ineffective length of a critical element in the notch root, obtained by a simple shear lag-type analysis. The notched strength is shown to depend on the ratio of notch radius to the critical element ineffective length. The model is able to predict changes in notched strength with composite parameters like fiber volume fraction, fiber bundle diameter and interfacial or matrix shear strength, and takes into account the composite microstructure.