Shell Fibers Research Articles

Comparing numerical simulation methods for evaluating hysteretic response of self-centering shear walls reinforced with SMA-ECC under cyclic loading

Under the action of earthquake, the traditional shear wall structure has the problems of excessive residual deformation and macroscopic cracks. The SMA-ECC composite material formed by the combination of smart materials such as shape memory alloy (SMA) and high ductility engineered cementitious composite (ECC) not only has good energy dissipation capacity, but also can obtain superior self-centering ability and damage self-healing ability, thereby improving the seismic performance and durability of shear wall structures. In this paper, in order to explore the nonlinear behavior of the self-centering shear wall under earthquake action and accurately simulate it, ECC and SMA material tests are carried out to establish the uniaxial constitutive relationship of the material. Using OpenSees finite element analysis platform, considering the micro and macro perspectives, a variety of finite element models are established, namely layered shell model, fiber model and multi-vertical rod model. Combined with the low-cycle reciprocating loading test of shear walls, the numerical simulation results are compared with the experimental data. By considering the parameters such as yield load, peak load and simulation time, the feasibility, stability and calculation efficiency of these models are evaluated. The results show that among the three models, the model based on fiber element can capture well the hysteretic response of new materials, and simulate the hysteretic performance, pinch effect and stiffness degradation of various shear wall members. The simulated values and experimental values can be well matched. Compared with the microscopic model, the computational efficiency of the fiber model is greatly improved, and the model has good feasibility, accuracy and efficiency.This work provides a basis for further research on the optimization of design parameters of SMA-ECC shear wall.

Development and characterization of glass fiber composites impregnated with limestone powder and bagasse fiber

Abstract Materials development is essential for all industries to meet the current demands Limestone powder (LS), coconut shell fiber (CSF) and sugarcane bagasse fiber (SBF) were impregnated in a laminated glass fiber polymer matrix. The fiber to matrix ratio is 50 %, while SBF and CSF start replacing natural fibers at a rate of 5–15 %, and LS is always 5 %. The proposed fiber-reinforced composites were manufactured by compression molding (CMM) and the test samples were cut according to the ASTM for tensile, impact, moisture, scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermogravimetric (TGA) tests. The results showed that the strength of the materials is influenced by the impregnation of the fibers into the matrix phase. Impregnation of natural fibers in glass fiber composite structures at 10–15 % loading demonstrated a weight saving of 7–8 %, tensile strength ranging from 330 to 350 MPa, maximum moisture absorption of 3.4 g, and thermal stability around 300 °C. Addition of limestone powder resulted in improved bonding ability, better surface finish, and reduced porosity, as demonstrated by SEM analysis.

The effect of hardness on bending value in manufacturing brake pads from shell and palm fiber

Motorbikes are one of the primary needs for many people because they are more effectively used to carry out community activities than public transportation. Because motorbikes are used so frequently, the braking system is one of the parts that must be updated. Brake pads are motorbike equipment that function to slow and stop the vehicle comfortably. The research aims to determine the characteristics of brake linings and the optimal composition of brake linings that are good for use. Brake pads are a component of motorcycle vehicles that are useful for slowing down and stopping the speed of the vehicle comfortably. The purpose of this study is to find out how the characteristics of palm shells and fibers if used as material for making brake linings. The method used is direct experimentation with a qualitative approach. The results obtained are the characteristics of brake pads made from filler palm shell powder and palm fiber with polyurethane matrix have a hard texture, solid brown, if viewed from the surface of the brake lining is a little rough because the fiber is too long. The test results showed the best hardness value of 91 R and the best bending test with a value of 10.21 kgf/mm2

Coconut Coir Fiber and Coconut Shell as Substitute to Fine Aggregates in Concrete Mortar Cubes

Coconut Coir Fiber and Coconut Shell as Substitute to Fine Aggregates in Concrete Mortar Cubes

Compressive Mechanical Properties and Energy Absorption of Cubic Spherical Hollow Cellular Material Based on the Rod and Curved Surface Structure

Cellular materials, such as lattices and honeycombs, were widely used for structural protection owing to their excellent mechanical properties. By combining the excellent characteristics of lattice and honeycomb curved surface structures, this study designed a cell called Cubic Spherical Hollow (CSH), which had the advantages of orthogonal isotropy and better spatial connectivity. Inspired by the micro-structural arrangement of bamboo fiber and conch shell, we designed the new CSH cellular materials through the interlayer offset strategy. Then, the effects of interlayer offset on the mechanical properties and compression deformation behavior were explored experimentally and simulatively. Compared with other cellular materials, CSH cellular materials exhibited excellent mechanical properties with higher specific strength and specific modulus. The arrangement offsets of the CSH cells between different layers led to a change in the deformation mechanism from a rod’s compressive mode to a combination of a rod’s compressive mode and curved surface’s bending mode. The initial peak stress and plateau stress decreased with the increased arrangement offsets of the CSH since the extruded protrusions of the structure filled the holes and reduced the lateral expansion behavior of the material in the pressurized environment. This phenomenon also reduced the transverse expansion and prevented the sudden change in stress in the constrained space, indicating that the structural deformation was stable and had excellent cushioning and energy absorption properties. In this study, the cellular material design strategy opens a new avenue for energy absorption.

Inflammation-responsive PCL/gelatin microfiber scaffold with sustained nitric oxide generation and heparin release for blood-contacting implants

Delayed endothelialization, the excessive proliferation of smooth muscle cells (SMCs), and persistent inflammation are the main reasons for the implantation failure of blood-contacting materials. To overcome this problem, an inflammation-responsive, core-shell structured microfiber scaffold is developed using polycaprolactone (PCL), selenocystamine-modified gelatin (Gel-Se), L-ascorbyl 6-palmitate (AP), and dexamethasone as the fiber shell, with poly (l-lysine) (PLL) and heparin incorporated in the fiber core. Superhydrophilic microfiber scaffolds exhibit antifouling properties that inhibit protein adsorption and blood cell adhesion, thereby effectively mitigating the risk of acute thrombosis. The continuous release of heparin and sustained generation of nitric oxide (NO) through the catalytic decomposition of S-nitrosothiols by selenocystamine lead to a biomimetic endothelial function for the enhancement of blood compatibility. The inflammation-responsive compound AP can detoxify excess reactive oxygen species (ROS) while controlling the release of dexamethasone to reduce chronic inflammation. We demonstrate the ability of microfiber scaffolds to reduce thrombotic and inflammatory complications, inhibit SMC proliferation, and promote rapid endothelialization both in vitro and ex vivo. Hence, microfiber scaffolds are robust and promising for blood-contacting implants with enhanced antithrombogenicity and anti-inflammatory capabilities.

Fabrication and Testing Methods for Assessing Mechanical Properties of Luffa Fiber and Marine Shells Reinforced with Epoxy

Fabrication and Testing Methods for Assessing Mechanical Properties of Luffa Fiber and Marine Shells Reinforced with Epoxy

An Approach Toward Assessing Linear Low-Density Polyethylene/Alkali-Treated Peanut Shell Fiber Blends for Rotational Molding

In order to improve the mechanical properties of polymer composites, natural fibers are being employed more and more as reinforcements. However, incorporating natural fibers can be difficult in rotational molding, a process used to make hollow plastic objects like kayaks and fuel tanks. Bi-axial rotation is a procedure that can result in fiber aggregation and is challenging to regulate. The optimal combination of NaOH-treated peanut shell powder (TPSP) and linear low-density polyethylene (LLDPE) for rotational molding was examined in our research reported in the manuscript. Processability was assessed using a variety of testing techniques, such as Fourier transform infrared spectroscopy (FTIR), particle size distribution, bulk density, melt flow index (MFI), differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). Significant peaks with TPSP concentrations in LLDPE ranging from 10 to 22% were shown by the FTIR. Blends of TPSP with LLDPE containing more than 18% TPSP were not acceptable for rotational molding due to poor flowability, as shown by particle size and bulk density investigations and supported by MFI data. According to our study, a 16% TPSP blend was the best formulation for rotational molding since it improved the thermal stability and increased the crystallinity by around 10%.

Sustainable engineering polymer composites fabricated using delignified bamboo fiber as reinforcement and walnut shell powder as filler

Developing sustainable engineering materials using renewable resources and agro-wastes represents an effective method for reducing carbon emissions and environmental pollution. In this study, a novel approach to fabricating high-performance biomass-based polymer composites was presented. Specifically, partially delignified bamboo fiber (DBF) and walnut shell powder (WSP) were incorporated into the matrix, namely melamine-hexamethylenediamine-urea (MHU) resin which was previously known for its excellent interfacial compatibility. Mechanical property investigations show that the DBF, acting as the reinforcement, provided the hybrid composites with high flexural and tensile strength up to 220 and 120 MPa, respectively, greatly surpassing those of commercial wood-plastic composites, wood-based composites, and natural wood, making them promising structural materials. As the filler, walnut shell powder endowed the composites with high hardness (Shore D > 90) and an appealing mirror-like surface gloss. Owing to the protection provided by the MHU matrix, the composite containing 38 % MHU exhibited outstanding flame retardancy (UL 94-V0 grade), which was further supported by cone calorimeter test (CCT) results. An unexpected and intriguing finding is that the composites exhibited fluorescence under UV irradiation. The rare silvery-grey fluorescence color imparted self-anticounterfeiting property to the composites. This study demonstrated the significant potential of bamboo fiber and walnut shell in the development of sustainable engineering materials.

Effect of drilling process parameters on agro-waste-based polymer composites reinforced with banana fiber and coconut shell filler

Effect of drilling process parameters on agro-waste-based polymer composites reinforced with banana fiber and coconut shell filler

Enhanced multifunctional sensing in human motion with speed-controlled coaxial wet-spun hollow MWCNT-TPU/TPU smart fibers

In the field of personal health management and athletic performance optimization, the demand for multi-parameter human signal monitoring devices is rapidly increasing. Currently, flexible sensors produced through wet spinning techniques face challenges of simplistic structure and functionality, as well as difficulty in balancing strength and sensitivity. In-depth research is needed to develop high-performance wet spinning techniques, which will lay the foundation for commercial smart garments capable of unobtrusively monitoring human motion in the future. This study innovatively employs specialized slurry formulations and spinning speed controls to utilize the timing differences in fiber precipitation and the affinity among similar materials. Through the coaxial wet spinning process, it enables the continuous, large-scale manufacturing of hollow core–shell fibers, MT/T-S5, which feature a dense inner layer and a porous outer conductive layer. This special structure endows the fibers with high strength, high signal stability, and capabilities for both active and passive heating. These fibers achieve a maximum gauge factor (GF) 65.2 in stretch sensing applications and can detect pressures as low as 0.1 N. The MT/T-S5 smart fibers can sense human joint movements, and through connection with an Arduino microcontroller, they can control a robotic hand and perform independent and real-time motion detection of five fingers to distinguish gestures. This research not only provides a new type of fiber material for the development of future smart textiles but also reveals a formation mechanism for hollow core–shell fibers in the field of wet spinning. This discovery can offer valuable inspiration for fiber structural design in future research.

Thermal energy storage performance of liquid polyethylene glycol in core–shell polycarbonate and reduced graphene oxide fibers

Thermal energy storage is a promising, sustainable solution for challenging energy management issues. We deploy the fabrication of the reduced graphene oxide (rGO)–polycarbonate (PC) as shell and polyethylene glycol (PEG) as core to obtain hydrophobic phase change electrospun core–shell fiber system for low-temperature thermal management application. The encapsulation ratio of PEG is controlled by controlling the core flow rate, and ~ 93% heat energy storage efficacy is apparent for 1.5 mlh−1 of core flow rate. Moreover, the prepared fiber possesses maximum latent melting and freezing enthalpy of 30.1 ± 3.7 and 25.6 ± 4.0 Jg−1, respectively. The transient dynamic temperature vs. time curve of the rGO-loaded phase change fiber demonstrates the delay of fiber surface temperature change compared to pristine fiber. We indeed show that the tunable heat transfer and thermal energy storage efficacy of phase change fiber is achieved via controlled liquid PEG delivery and the addition of rGO in shell architecture. Notably, the effectiveness of unique phase change material (PCM)–based core–shell fibers is concluded from advanced scanning thermal microscopy (SThM) and self-thermoregulation tests.

Mechanical properties and formulation of hydrophilic fiber and shrimp shell combination as a novel eco-friendly dental restoration material

This study evaluates the mechanical properties and formulation of dental restoration material comprised of cellulose acetate (CA) from water hyacinth and chitosan (C) from white shrimp shells. The research phases included extraction, formulation, functional group testing, antibacterial, toxicity, water absorption and solubility, compressive, shear, tensile, hardness, microleakage, thermal expansion, and shrinkage. The experimental data were analyzed using probit regression, one-way ANOVA, and Kruskal-Wallis test. The data showed that CA and C had microxyl and amine groups, could inhibit S. mutans, and were non-toxic. Composite resins were divided into nine formulations with different concentrations: F1 (1 % CA + 3 % C), F2 (1 % CA + 5 % C), F3 (1 % CA + 7 % C), F4 (3 % CA + 3 % C), F5 (3 % CA + 5 % C), F6 (3 % CA + 7 % C), F7 (5 % CA + 3 % C), F8 (5 % CA + 5 % C), and F9 (5 % CA + 7 % C). The F9 has mechanical strength close to the control group, with 113.33 μg/mm3 absorption, 80 μg/mm3 solubility, 32.67 Mpa compressive strength, 17.18 Mpa tensile strength, and no shrinkage. It shows that F9 has potential as an eco-friendly dental filling material. The present study completed the development of a formulation for a restoration material by combining water hyacinth fiber and shrimp skin chitosan. The outcomes of a comparative analysis of the mechanical properties of synthetic composite resins and water hyacinth fiber composites containing shrimp skin chitosan revealed that the F9 formulation (CA 5 % + C 7 %) exhibited the following fiber: absorption, compressive strength, tensile strength, hardness, and thermal expansion.

Coaxial electrohydrodynamic printing of core–shell microfibrous scaffolds with layer-specific growth factors release for enthesis regeneration

The rotator cuff tear has emerged as a significant global health concern. However, existing therapies fail to fully restore the intricate bone-to-tendon gradients, resulting in compromised biomechanical functionalities of the reconstructed enthesis tissues. Herein, a tri-layered core–shell microfibrous scaffold with layer-specific growth factors (GFs) release is developed using coaxial electrohydrodynamic (EHD) printing for in situ cell recruitment and differentiation to facilitate gradient enthesis tissue repair. Stromal cell-derived factor-1 (SDF-1) is loaded in the shell, while basic fibroblast GF, transforming GF-beta, and bone morphogenetic protein-2 are loaded in the core of the EHD-printed microfibrous scaffolds in a layer-specific manner. Correspondingly, the tri-layered microfibrous scaffolds have a core–shell fiber size of (25.7 ± 5.1) μm, with a pore size sequentially increasing from (81.5 ± 4.6) μm to (173.3 ± 6.9) μm, and to (388.9 ± 6.9 μm) for the tenogenic, chondrogenic, and osteogenic instructive layers. A rapid release of embedded GFs is observed within the first 2 d, followed by a faster release of SDF-1 and a slightly slower release of differentiation GFs for approximately four weeks. The coaxial EHD-printed microfibrous scaffolds significantly promote stem cell recruitment and direct their differentiation toward tenocyte, chondrocyte, and osteocyte phenotypes in vitro. When implanted in vivo, the tri-layered core–shell microfibrous scaffolds rapidly restored the biomechanical functions and promoted enthesis tissue regeneration with native-like bone-to-tendon gradients. Our findings suggest that the microfibrous scaffolds with layer-specific GFs release may offer a promising clinical solution for enthesis regeneration.

Innovative Eco-Friendly Concrete Utilizing Coconut Shell Fibers and Coir Pith Ash for Sustainable Development

Concrete is the most commonly used and essential material in the construction industry, and it is also the most widely utilized product globally. The construction industry is a rapidly expanding industry. To improve the efficiency and strength properties of concrete, researchers from all over the world continue to search for supplementary cementitious materials (SCMs) and industrial by-products that can be incorporated as alternative materials. The current study aimed to determine the effects of partially substituting coir pith ash (CPA) for cement in coconut shell concrete, in addition to utilizing steel and coconut fibers. Various percentages of CPA were used to replace cement in the concrete mixes, ranging from 5% to 20% by cement weight. Steel fibers were utilized in this study at volume ratios of 0.25%, 0.5%, 0.75%, and 1.0%, and coconut fibers were utilized at volume ratios of 0.1% to 0.5% with an increment of 0.1% in the concrete to achieve the desired results. Various properties have been examined, such as workability, mechanical, durability, and morphological tests. The addition of coir pith ash to concrete increased its compressive, flexural, and tensile strengths by 10.36%, 8.75%, and 7.7% at 28 days compared to control concrete. The incorporation of coconut fiber and coconut shell in concrete production improves its performance and strength while also preserving natural resources and offering a solution to the problem of disposing of solid waste.

Electrospun matrices for sustained drug release made by a PCL-chitosan blend shell and a PVA core

Core-shell electrospinning is a versatile technique for tissue engineering applications due to the possibility of uploading drugs in the core layer. The drug is protected by the shell layer that also allows its release by diffusion. The aim of the present work is the development of a drug release system for the release of doxorubicin, a chemotherapeutic agent commonly used for osteosarcoma treatment. In core–shell fibres, polycaprolactone (PCL) is often proposed for the shell layer as it is bioresorbable and biocompatible, but it is hydrophobic and lacks adhesive sites for cellular attachment. In this work, a PCL-chitosan blend was used for the shell layer to increase PCL hydrophilicity and to provide cell-recognition sites to support cell adhesion. Polyvinyl alcohol (PVA) has been used for the core layer and doxorubicin was introduced with a concentration of 100 µg/mL. Core-shell fibres of dimension of 300–500 nm were successfully obtained and doxorubicin was released in a sustained way up to 28 days.

Fabrication of pressure visual fiber based on liquid metal control thermochromic pigments

AbstractIn this study, pressure visual fibers (PVF) with a core‐shell structure were prepared using a coaxial wet spinning process. The fiber composite shell consists of a luminescent material (as a light source) and a thermochromic pigment (as a filter light source) mixed with a polyacrylonitrile (PAN) matrix. The fiber core layer, on the other hand, was made of gallium‐indium alloy liquid metal. In operation, the filter light source is activated by joule heat drive (resulting in the fading of the thermochromic pigment), and the PVF releases phosphorescence upon exposure to ultraviolet light. When a certain pressure is applied to the fiber shell, the liquid metal in the core layer is squeezed, resulting in a local cross‐sectional area reduction, an increase in local joule thermal power, and thus local discoloration. This localized compression, in combination with a small rated current and the presence of an ultraviolet light source, converts the mechanical force (strain and compression) into an optical response. The excellent electrical conductivity of the liquid metal, combined with its compatibility with the soft matrix, makes it a promising candidate for applications in smart textiles and flexible sensing.Highlights The technology of visual fiber controlled by current is presented. The bendability and controllability of visual composites are improved. The composite fiber can be visualized when stressed.

Development and Characterization of Hybrid Particulate-fiber Reinforced Epoxy Composites

Although considered wastes, animal fibers and gastropod shell particles are biodegradable, have low density, high stiffness, considerably high impact absorption capacity and relatively low cost. Therefore, they are finding increasing use as reinforcement materials in polymer composites. This research work studied the tensile, hardness, and wear resistance properties of hybrid snail shell (SSP) and chicken feather barb fibers (CFB) reinforced epoxy composites. The stir cast molding technique was utilized to synthesize the composite samples with 3, 6, 9, 12, 15, and 18 wt.% of the hybrid SSPs/CFB. Compared with the control samples, SSP/CFB hybrid reinforcements enhanced the mechanical properties of the composites. Composites with intermediate weight fraction of 9 wt.% SSP/CFB exhibited overall optimum properties when benchmarked against the control sample with approximately 37, 37, 133, 19, and 59% improvement in wear, hardness, impact, and ultimate tensile strength properties respectively. These enhancements suggested a synergistic effect of the two reinforcement phases. The results presented in this study demonstrated the potential of utilizing bio-derived waste materials for synthesizing eco-friendly composites.

Advancing Sustainable Acoustic Solution: Exploring the Sound Absorption Characteristics of Biodegradable Agricultural Wastes, Coconut Fiber, Groundnut Shell, and Sugarcane Fiber

Among the world's greatest threats is noise pollution particularly in megacities that affect the quality of life. This problem can cause negative effects on human health, disturbing emotion as well as human behavior. Natural fiber sound insulation materials have been demonstrated to be a potential substitute for the synthetic products currently employed in the sound insulation industry. Coconut fiber and sugarcane fiber happen to be biodegradable, earth-friendly, and present lower risks to the environment and human health. The research examines the sound absorption characteristics of natural biodegradable waste fibers (coconut fiber & sugarcane fiber) to evaluate their suitability as sound absorbers. The paper seeks to discover the internal workings of the sound absorption mechanisms of these materials and also to help design environmentally friendly acoustic solutions.

Oil palm waste-derived adsorbents for the sequestration of selected polycyclic aromatic hydrocarbon in contaminated aqueous medium

Carbonaceous adsorbents were synthesized from palm kernel shell and palm mesocarp fiber for the adsorption of phenanthrene (PHE) and the highly carcinogenic-benzo(a)pyrene (BaP). The structure and properties of the activated biochar were characterized using standardized analytical tools. The microscopic examinations carried out with SEM and BET results revealed mesoporous structures and interstitial spaces in the activated samples (AB-PKS and AB-PMS). Powder X-ray diffraction (PXRD) results showed that prepared sorbents are amorphous and that activation affected the amorphous cellulose on the surface of the microfibrils which led to a decrease in the intensity of some peaks. Fourier-transform infrared spectroscopy (FTIR) affirms the availability of surface moieties that may promote polycyclic aromatic hydrocarbon (PAH) removal or decontamination of aqueous media. The sorption isotherm and effect of pH on the adsorption of PHE and BaP onto the activated palm kernel shell (AB-PKS) and activated palm mesocarp fiber (AB-PMF) were investigated. The isotherm studies and error analysis (SSE and R2) confirm that the Freundlich model best fits experimental results for AB-PMF; while, the Langmuir model best describes AB-PKS sorption of BaP and PHE, respectively. The optimal removal efficiency for PHE was between 84 and 100% while that of BaP was between 68 and 87% with maximum adsorption capacity (qmax) of 19.38–21.98 mg/g and 1.24–13.26 mg/g, respectively. The optimum pH condition for removing PHE is less than 7 and above 7 for BaP. Therefore, the conversion of waste materials to useful sorbents, as well as preliminary adsorption test results obtained suggests a cleaner and cost-effective pathway for waste management and water treatment.