Location Of Fibers Research Articles

Sialkoti paper used by Pahari artists: raw materials and fibre analysis

This study aims to characterise the so-called Sialkoti paper used to produce Pahari drawings preserved today in the Wereldmuseum in Leiden (Netherlands) (WML). These works originate from the Punjab Hills in India (today Himachal Pradesh) and are commonly known as ‘Pahari miniature paintings’. The paper upon which these drawings are executed is said to have been produced in Sialkot during the eighteenth and nineteenth centuries when papermaking was an integral part of an overall regional economy correlated with other sectors such as agriculture and the textile industry. Although the term Sialkoti refers to identified papermills in Sialkot (now Pakistan), the paper from this region is yet to be subjected to a systematic study. This article therefore explores the paper(s) in question through macro- and microscopic observations of structure, pulp and fibres. The study of historical sources, complemented by the analysis of paper samples and fibre identification, has revealed that the pulp would have been prepared from a variety of manufactured products using different technologies, such as rags, cloth, mats, rope and other plant-based materials made from local bast fibres which, once tattered, were recycled to prepare the pulp. Microscopic study reveals that a variety of fibre combinations under different conditions and processing steps were used, in particular sunn hemp fibre (Crotalaria juncea L.), a plant species that has until now rarely been identified in historical paper. In addition, the presence of kenaf and jute fibres, as well as a significant quantity of cotton fibres, have also been demonstrated. To overcome the lack of comparative materials, our work was supported by a comparative study of several materials made from sunn hemp now held in the Ethnobotany Collection at Kew Gardens. Samples were taken from these materials and provided useful reference micrographs for the identification of the WML samples. The quality of the paper used by Pahari artists, as well as the raw materials available and their processing, are discussed in detail. Putting all the data, including technical and historical information into perspective, we conclude that the Pahari artists used a paper of inferior quality compared to other types of paper used for other purposes such as the creation of illuminated manuscripts in the Punjab plains. This study therefore provides useful analytical and material evidence that complements previous historical, technical and anthropological studies.

Alkali Pretreatment and Analysis Of Biomass Content Of Narlisaray Population and Vezir Type Cannabis Plant

The cell wall of the hemp plant consists of cellulose, hemicellulose, and lignin cross-linked to these components. In such a structure, lignin is considered an undesirable byproduct in the production of textiles, paper, and biofuels from hemp. Therefore, the removal of lignin is essential for the industrial utilization of cellulose from hemp. In this study, lignin removal processes were conducted for the first time on the (native to Anatolia) Narlısaray population and the registered Vezir hemp. Alkaline (NaOH) treatment was preferred for pre-treatment due to its relatively low cost, lower energy requirements, and reduced risk factors. Structural changes before and after alkaline pre-treatment were compared using FT-IR spectra, SEM, and EDX analyses of the biomass. Examination of elemental trace values revealed that the O:C ratios of Narlısaray and Vezir fibers increased to 0.84 and 0.85, respectively. The increase in the O:C ratio indicated the removal of lignin, while the nearly identical ratios suggested that the lignin cross-linking energies in both local hemp fibers were almost the same. Additionally, SEM images provided clear information regarding the structural changes in Narlısaray and Vezir fibers before and after the lignin removal process.

Optimization design and 3D printing of curvilinear fiber reinforced variable stiffness composites based on polar coordinate sweeping

The 3D printing of curvilinear fiber reinforced variable stiffness structures (CFRVSSs) provides new opportunities for innovative design and fabrication of complex components in response to rising demand for high-performance and lightweight components in aerospace, railway, and other fields. In this paper, we get rid of the limitations of existing research on the structure of open-hole plates and aim to investigate complex structures with large curvature. Considering the characteristics of 3D printing and service load, an optimization design method based on polar coordinate sweeping was proposed for CFRVSSs. The consistency factors between the fiber distribution (direction, content) and stress distribution (direction, magnitude) were established. Through quantitative analysis, the directional consistency factor between the optimized local fibers and stresses was enhanced by a factor of 3.69, and the correspondence factor between the fiber content and the stress magnitude was enhanced by a factor of 3.8. Furthermore, the calculation method for curve spacing and curve arc length based on polar coordinate sweeping were proposed to minimize the forming errors caused by CFRVSSs 3D printing. The design and fabrication of a high-speed rail tie rod structure were carried out using the optimization design method and 3D printing process in current research. As a result, the ultimate tensile strength of the optimized curvilinear fiber reinforced tie rod structure increased by 156 % compared to the unoptimized straight-line fiber reinforced tie rod structure. The method proposed in this study has a wide range of applications for the design and fabrication of complex components with large curvature in the engineering field.

A THERMAL BEHAVIOUR STUDY OF NATURAL FIBER-REINFORCED POLYMER COMPOSITE/HONEYCOMB CORE SANDWICH PANELS

The unique honeycomb structure has provided good modulus with a lightweight material, especially in aerospace and vehicle applications. Realizing that the thermal analysis of natural fiber honeycomb sandwiches was still lacking in observation, the research needs to investigate thermal transfer characteristics to promote engineering demand. The objective of this research was to investigate honeycomb sandwiches' thermal behaviour by implementing local natural fibers of coconut, oil palm, and sugar cane for sheet plate structure through experimental and numerical analysis. The natural fiber was varied by weight content with the ratio of composite given in a range of 0%wt. - 8%wt. The results have demonstrated that the face sheet plate was paramount part to absorb thermal flow. The study displayed the low thermal conductivity of the face sheet will counter significantly the heat transfer of the honeycomb structure. The experimental investigation found that the coconut fiber successfully performs as an insulator in a honeycomb sandwich which reached 6.78 W.m-1K-1 of thermal conductivity which was an 85.86% improvement as an insulator. While palm oil and sugar cane presented at 11.12 W.m-1K-1 and 10.59 W.m-1K-1, it was slightly higher compared to the coconut. In the numerical investigation, fiber distribution development was successfully performed in a honeycomb sandwich sheet plate composite. The thermal conductivity showed a difference from the experimental, where the higher thermal resistance was shown by palm oil and sugar cane at 8.22 W.m-1K-1 and 8.16 W.m-1K-1, respectively.

NATURAL FIBERS FOR SUSTAINABLE CONCRETE MIXES

To meet the sustainable development goals, novel concrete mixes are necessary. Natural fibers are becoming an interesting new element for concrete mixes, because these fibers are biomaterials recovered from residual biomass and fit in the concept of the circular bioeconomy. In this paper, we catalog research insights on concrete mixes with natural fibers, and pay special attention to natural fibers that are available in the Metropolitan District of Quito, Ecuador, to use local bio-based materials. We focus on examining information from the literature on how natural fibers influence the mechanical properties of concrete, namely the tensile, compressive, and flexural strength. Based on this analysis, we have developed recommendations on which natural fibers are of interest for further experimental research, with the aim to develop sustainable concrete mixes for Quito. Moreover, this paper gives insights in how natural fibers influence the mechanical properties of concrete and proposes a framework that translates to other regions and cities for the selection of local and adequate natural fibers.

Valorization and biorefinery of local agricultural and textile wastes through mycelium composites for structural applications

Abstract Manufacturing of mycelium-based composites is an emerging biorefinery technology toward the development of environmentally positive materials within the circular economy: it benefits from waste and industrial by-products upcycling while excelling in biodegradability. This study investigates the compressive behavior of materials repurposed from local agricultural wastes (tree nuts and crop wastes in California’s Central Valley), using the fungal mycelium of Pleurotus ostreatus and Ganoderma lucidum, well-known edible and medicinal species. We also explore the hybridization of these mycelium-based composites with local textile waste fibers as reinforcements. Following guidelines from several ASTM standards, the compressive behavior of these composites is analyzed to determine the impact of biomass processing, composition, fungal species used, and post-processing strategy. We propose a post-processing strategy based on a short exposure to sodium chloride solutions in ambient conditions, to de-activate mycelium and prevent its fruiting, replacing the established energy-intensive heat-based post-processing. This work aims at contributing to the decarbonization of the built environment and the construction industry in particular, through materials designed with upcycled waste (agricultural and textile), fungal mycelium and low-carbon footprint processes.

Effects of relative humidity, alkaline concentration and temperature on the degradation of plain/coated glass fibers: Experimental investigation and empirical degradation model

Glass fiber reinforced polymer (GFRP) rebars are commonly considered as a substitute for conventional steel reinforcements in concrete structures to avoid possible steel corrosion. However, the tensile strength of GFRP rebars may degrade with time due to the degradation of glass fibers under H2O/OH– attack in a moist concrete with a high pH level (∼13.6). The purpose of this study is to investigate the degradation of glass fibers under exposure to various temperatures (23, 40 and 60 ℃), relative humidities (45%, 75%, 95%) and pH levels (i.e., pH = 7, 11, 12 and 13), and then build up a comprehensive database incorporating the information on physical, chemical and mechanical properties of conditioned fibers. Experimental results show that direct exposure to an alkaline solution is highly aggressive to plain glass fibers, resulting in violent chemical reactions (i.e., leaching and dissolution) and a significant reduction in the fiber radius and tensile strength. In contrast, the matrix coating (thickness of ∼ 1.5 μm) on the fiber surface can effectively delay the penetration of H2O/OH–, protecting fibers from radius reduction, chemical reaction and tensile strength degradation. The degradation of GFRP rebar with the same fiber and matrix is also analyzed to illustrate the inherent relationship between the macroscopic tensile strength performance of conditioned rebars and the degradation of local glass fibers at the microscopic level. The findings in this study yield useful information on the degradation of local glass fibers in the GFRP rebar, supplying engineers with a better understanding of GFRP degradation mechanism in an alkaline environment.

Performance of local date palm fibers in cementitious materials

Performance of local date palm fibers in cementitious materials

Mechanical performance of spun-cast full-scale precast pipes incorporating hybrid conventional rebar cage and steel fibers

Precast reinforced concrete (RC) pipes are an important component of urban infrastructure for conveyance of stormwater and sewage disposal. This study investigates the mechanical performance of spun-cast precast full-scale pipes under three-edge bearing test (TEBT) and patch or point load tests for replicating the field loading scenarios. Six types of precast pipes incorporating various amount of conventional rebar reinforcement and local steel fibers were tested. Straight steel fibers of 25 mm length were cut from locally manufactured long steel wires. Two steel fiber dosages (i.e., 20 kg/m3 and 40 kg/m3) in concrete mixture were examined for mechanical behavior of pipes along with conventional rebar cage. It was observed that full-scale precast pipes without steel fibers and conventional rebar cage failed in an abrupt manner into various pieces. However, pipe made with concrete mixture incorporating steel fibers only without conventional rebar cage also failed into pieces but showed post-peak behavior and fiber crack bridging phenomena. Pipes having double conventional steel reinforcement ratio showed 60% higher ultimate load. Pipes incorporating 20 kg/m3 and 40 kg/m3 along with conventional rebar cage showed 10% and 30% higher ultimate load compared to that of identical pipe without steel fibers. Improved deflection softening and hardening behaviour were observed for pipes with fibers. Furthermore, multiple secondary cracks were observed during TEBT for pipe specimens incorporating fibers. Similarly, higher ultimate load and improved cracking behavior was observed under patch load for pipe specimens incorporating steel fibers. All the tested pipes incorporating steel fibers and conventional rebar cage satisfied the Class III and Class IV requirements of ASTM C76. It can be envisioned that the implementation of hybrid spun-cast pipes incorporating conventional rebar cage and local steel fibers lead towards the development of economical pipes for controlling the premature cracking and improved structural behaviour.

Effect of Blend Composition on Barrier Properties of Insulating Mats Produced from Local Wool and Waste Bast Fibres

This paper concerns the management of natural waste fibres. The aim of this research was the production of multifunctional acoustic and thermal insulation materials from natural protein and lignocellulosic fibre wastes, according to a circular bioeconomy. For the manufacture of the materials, local mountain sheep wool and a mixture of bast fibre waste generated by string production were used. Insulating materials in the form of mats produced by the needle-punching technique with different fibre contents were obtained. The basic parameters of the mats, i.e., the thickness, surface weight and air permeability were determined. To assess barrier properties, sound absorption and noise reduction coefficients, as well as thermal resistance and thermal conductivity, were measured. It was shown that the mats exhibit barrier properties in terms of thermal and acoustic insulation related to the composition of the mat. It was found that mats with a higher content of the bast fibres possess a greater ability to absorb sounds, while mats with higher wool contents exhibit better thermal insulation properties. The produced mats can serve as a good alternative to commonly used acoustic and thermal insulating materials. The production of the described materials allows for a reduction in the amount of natural fibre waste and achieves the goal of "zero waste" according to the European Green Deal strategy.

Photosensitive and Conductive Hydrogel Induced Innerved Bone Regeneration for Infected Bone Defect Repair.

Repairing infected bone defects is a challenge in the field of orthopedics because of the limited self-healing capacity of bone tissue and the susceptibility of refractory materials to bacterial activity. Innervation is the initiating factor for bone regeneration and plays a key regulatory role in subsequent vascularization, ossification, and mineralization processes. Infection leads to necrosis of local nerve fibers, impeding the repair of infected bone defects. Herein, a biomaterial that can induce skeletal-associated neural network reconstruction and bone regeneration with high antibacterial activity is proposed for the treatment of infected bone defects. A photosensitive conductive hydrogel is prepared by incorporating magnesium-modified black phosphorus (BP@Mg) into gelatin methacrylate (GelMA). The near-infrared irradiation-based photothermal and photodynamic treatment of black phosphorus endows it with strong antibacterial activity, improving the inflammatory microenvironment and reducing bacteria-induced bone tissue damage. The conductive nanosheets and bioactive ions released from BP@Mg synergistically improve the migration and secretion of Schwann cells, promote neurite outgrowth, and facilitate innerved bone regeneration. In an infected skull defect model, the GelMA-BP@Mg hydrogel shows efficient antibacterial activity and promotes bone and CGRP+ nerve fiber regeneration. The phototherapy conductive hydrogel provides a novel strategy based on skeletal-associated innervation for infected bone defect repair.

Recycling of waste tire rubber as aggregate in impact-resistant engineered cementitious composites

With the development of modern transportation, the recycling and reusing of waste tires have gradually become a global concern. This paper was indented to develop impact-resistant engineered cementitious composites (ECC) with the application of waste tire rubber as the aggregate. The local PVA fibers, as well as the rubber crumb derived from waste tire with the replacement ratio up to 40 %, were applied to make ECCs. The basic mechanical behaviors of rubber-modified ECC were first investigated with uniaxial compressive and tensile tests. The impact tests of rubber-modified ECC were further conducted under different environmental temperatures ranging from −50 ℃ to 150 ℃, as well as different impact heights from 100 mm to 500 mm. It was concluded that the rubber-modified ECCs are more suitable to be applied as impact-resistant material in cold regions, as the rubber-modified ECC has higher energy dissipation capacity than normal ECC, especially under cold temperatures.

Channel characteristics estimation based on a secure optical transmission system with deep neural networks.

Optical transmission security has attracted much attention. In recent years, many secure optical transmission systems based on channel characteristics are proposed. However, there are many drawbacks with these systems, such as separated plaintext and key transmission, low key generation rate (KGR), insecurity when the eavesdropper has acquired the lengths of the local fibers utilized by legal parties. To solve the above problems, we propose a novel secure optical transmission system based on neural networks (NNs), which are employed to estimate channel characteristics. By training NNs locally and transmitting pseudo-keys, the proposed system can transmit the plaintext together with key, transforming the key dynamically. Moreover, since the channel characteristics for legal parties and eavesdropper are not completely identical, the NNs trained by legal parties and eavesdropper are inconsistent. Even though the eavesdropper has attained the lengths of local fibers wielded by legal parties, the NN model trained by the legal parties is still unavailable to illegal eavesdropper. The final key is generated by the trained NN and pseudo-key, so the keys generated by legal parties and eavesdropper are dissimilar. The simulation results prove the feasibility of the proposed system with the transmission distance of 100 km and the bit rate of 100 Gbps. Meanwhile, if plaintext and key have equivalent code length, the KGR of 50 Gbps for legal parties and the key disagreement rate (KDR) of 50% for illegal eavesdropper will be realized.

Impact resistance of engineered geopolymer composite (EGC) in cold temperatures

This paper was intended to investigate the impact resistance of engineered geopolymer composite (EGC) in cold temperatures. The ambient cured EGC based on local PVA fibers, which has favorable environmental and economic benefits, was first developed and tested under uniaxial compressive and tensile loading conditions. The drooping hammer test machine retrofitted with a liquid nitrogen canister was applied to conduct the impact tests of EGC specimens under different cold temperatures, i.e., −10 ℃, −20 ℃ and −50 ℃. The conventional engineered cementitious composite (ECC) specimens and the corresponding cement mortar were also tested as the control groups. The influences of alkali concentrations on the compressive, tensile and impact behaviors of EGC were investigated. According to the experimental results, it was found that the developed EGC could have comparable compressive strength and tensile behaviors with ECC. For both EGC, ECC and their corresponding matrixes, the impact load increased while the ultimate displacement decreased when the temperature dropped from −10 ℃ to −50 ℃. It was also found that the energy dissipation coefficient of EGC specimens increased with the decrease of temperature, indicating that EGC materials have preferable impact resistance under low or ultra-low temperature environments.

Mechanical performance and feasibility analysis of green concrete prepared with local natural zeolite and waste PET plastic fibers as cement replacements

Green concrete is a sustainable composite material having natural and waste materials replacing carbon dioxide gas-producing cement, and aggregates in the concrete. Thus, it significantly contributes in reducing greenhouse gas emissions and improves the economic viability of a country as well. Literature suggests that research on the development of green concrete is evolving with widely-available natural and waste materials. Considering the need for the development of green concrete, the current research is conducted. It was hypothesized that the mechanical performance of green concrete prepared by substituting cement with Natural Zeolite (NZ) and waste Polyethylene Terephthalate (PET) fibers will yield stronger, cost-effective, and environmentally green concrete for the construction industry. The microstructure, morphology, and surface properties of the locally extracted NZ were characterized using X-ray Diffraction, SEM and BET, respectively. The influence of quantity, shape, orientations, and surface of NZ and PET fibers along with varying curing times, i.e., 28, 90, and 180 days were considered for experimentation. The main findings of this study are that two optimum proportions for the concrete mixtures are obtained: the first one was 10 % NZ while the other one was 2.5 % PET, and 15 % NZ, and 1.0 % PET. These optimum mixing ratios were found to enhance the compressive strength of concrete, reduce the production cost, and reuse waste PET bottles effectively, which are key points of this study. Furthermore, the workability of the fresh concrete was improved with higher proportions of PET rather than NZ. Finally, the findings of the current research highlight a pragmatic remedial solution for saving energy, turning non-decomposable waste into useful materials for green concrete, and simultaneously contributing to a cleaner environment.

Image Based Measurement of Individual Fiber Lengths for Randomly Oriented Short Fiber Composites

Among a wide range of fiber-reinforced composites, those with randomly oriented short fibers, which are also known as random-chopped fiber-reinforced composites (RaFCs), are the most common composites owing to its ease of manufacturing, flexibility of composite shapes, and good material properties, including light weight and high stiffness. These properties of RaFCs are involved with the lengths and distributions of fibers inside the composites. However, inspecting the fiber lengths and distribution remains a challenging problem, particularly when the lengths and locations of individual fibers need to be distinguished using only X-ray transmission images. The main difficulty arises from the variety of fiber widths and their frequent intersections. To address this problem, this paper proposes a comprehensive software system to localize fibers and measure their lengths. Our system is inspired by a previous work for tracing human hair strands. To adopt the previous method for RaFCs, our system extends classic Gabor filter to explore the locally best parameter sets to suit different fiber shapes. With this adaptive filter, we can extract the locations and orientations of local fibers more robustly for RaFCs. Then individual fibers are traced by solving an initial value problem of an ordinary differential equation. To avoid erroneous tracing which typically occurs at intersections, our method traces only the non-intersecting parts of the fibers initially. After that, we connect the fiber segments using the proximity of their endpoints and the orientations. Through experimental validations on different fiber samples, we demonstrate the stability of the fiber tracing and the robustness of the fiber length calculation. Our system works properly even for X-ray radiographic images of heavily tangled fibers in carbon-fiber-reinforced thermoplastic laminates taken by X-ray Talbot–Lau interferometer.

Application of numerical simulation to solid phase-microextraction for decreasing of extraction time of pyrene and phthalate esters on solid coatings

Reynolds-Averaged Navier-Stokes (RANS) approach with the k-ε closure model is employed for the first time to simulate direct Solid-Phase Micro-Extraction (SPME) computationally. Simulations are performed by using COMSOL Multiphysics in order to examine methods to decrease the extraction time. Experiments are also conducted to support data obtained from the numerical framework. Di-n-Butyl Phthalate (DNBP) and etched steel wire are chosen as the analyte and the adsorbent, respectively. Stirring rate, fiber's location, stirrer magnet's size, and the method of sample rotation are examined to decrease the extraction time. In addition, the effects of adding a baffle to the vial and implementing a periodic function for stirring the sample are studied. Increasing the stirring rate from 700 to 3000 rpm reduces the extraction time from 50 to 36 minutes. Present results suggest that changing the fiber's location and implementing a periodic stirring pattern significantly decrease the extraction time of SPME. The optimum fiber's location is found at 7.5 mm far from the vial's center, which leads to a 51% decrease in the extraction time. Furthermore, using a periodic stirring pattern results in a 60% decrease in the extraction time compared to the traditional uniform stirring pattern. To examine the robustness and reliability of the presented framework, two additional analytes, namely pyrene and Dioctyl phthalate (DOP), are chosen with one additional fiber, Al2O3. In this regard, the additional materials are used in the framework to investigate the effects of fiber's location and stirring pattern. By optimizing the fiber's location, the extraction time is reduced by 36% and 40% for SPME of pyrene and DOP, respectively. On the other hand, by using a periodic stirring pattern, the extraction time is reduced by 42% and 46% for SPME of pyrene and DOP, respectively.

Channel Characteristics Based Adjustable Fingerprint for Identity Authentication in WDM-PON With Deep Neural Networks

Wavelength-division-multiplexed passive optical network (WDM-PON) has been widely deployed for the high-speed, reliable transmission and low-cost properties. The physical layer identity authentication in WDM-PON becomes increasingly prominent. Recently, many device fingerprint based identity authentication schemes are proposed. However, these schemes only realize constant fingerprint, which will be acquired by illegal ONU after optical spectrum analysis. Therefore, the higher-level security requirement cannot be satisfied. To solve the problem, we propose a physical layer identity authentication method in WDM-PON by exploiting the channel characteristics based adjustable fingerprint with deep neural networks (DNNs). By secretly negotiating with legal optical network units (ONUs) on the lengths of the local fibers applied by them, the optical line terminal (OLT) can acquire the unique channel characteristics fingerprint obtained by each legal ONU. It should be noted that the fingerprint can be adjusted by modifying the length of the local fiber. Moreover, the same number of DNNs as legal ONUs are trained for fingerprint identification. Simulation results show 100% identification accuracy for illegal ONU when the length deviation between two fibers applied by legal ONU and illegal ONU is greater than 1.5 km. Meanwhile, the identity of each legal ONU can be recognized with 100% accuracy.

Effects of different mixing ratio parameters on mechanical properties of cost-effective green engineered cementitious composites (ECC)

ECC is an advanced construction material with tensile strain hardening characteristics and multiple cracking behavior, which is very attractive to the construction industry. However, the oiled polyvinyl alcohol (PVA) fibers and fine silica sand widely used in traditional ECC lead to high cost, and high cement content will lead to high carbon footprint. In order to reduce the cost and severe environmental concern, the paper develops a low-cost green ECC. The means adopted is to replace oiled PVA fibers and fine silica sand with hybrid local fibers (unoiled PVA fibers and basalt fibers) and river sand, respectively and thus decreases the ECC cost, and replace the cement with the high-volume fly ash and silica fume and thus improve the green. And then the influences of river sand particle size, sand-binder ratio, water-binder ratio and fiber content on mechanical properties of ECC are studies by some macro experiments. Furthermore, a new method which can comprehensively evaluate the flexural toughness of ECC from two aspects of energy and strength is proposed. In addition, the microstructure of the samples was studied by scanning electron microscopy. Test results showed that the low-cost green ECC can be developed by using local materials, but the grain size of river sand should not exceed 0.85 mm, the sand-binder ratio should not exceed 0.5, and the water-binder ratio should not be less than 0.3. Although the basalt fiber can effectively reduce the average crack width, the strength of basalt fiber decreases according to the fiber orientation, resulting in its low contribution to flexural toughness.

Excellent!: Textiles from Mali

Excellent!: Textiles from Mali