Subjects -> TEXTILE INDUSTRIES AND FABRICS (Total: 41 journals)
    - CLOTHING TECHNOLOGY AND TRADE (6 journals)
    - TEXTILE INDUSTRIES AND FABRICS (35 journals)

TEXTILE INDUSTRIES AND FABRICS (35 journals)

Showing 1 - 16 of 16 Journals sorted alphabetically
Achiote.com - Revista EletrĂ´nica de Moda     Open Access  
Asian Journal of Textile     Open Access   (Followers: 6)
Autex Research Journal     Open Access   (Followers: 1)
Composites Science and Technology     Hybrid Journal   (Followers: 170)
Fashion and Textiles     Open Access   (Followers: 13)
Fashion Practice : The Journal of Design, Creative Process & the Fashion     Hybrid Journal   (Followers: 13)
Fibers     Open Access   (Followers: 4)
Fibre Chemistry     Hybrid Journal   (Followers: 2)
Focus on Pigments     Full-text available via subscription   (Followers: 3)
Geosynthetics International     Hybrid Journal   (Followers: 4)
Geotextiles and Geomembranes     Hybrid Journal   (Followers: 5)
Indian Journal of Fibre & Textile Research (IJFTR)     Open Access   (Followers: 6)
International Journal of Fashion Design, Technology and Education     Hybrid Journal   (Followers: 15)
International Journal of Textile Science     Open Access   (Followers: 7)
Journal of Engineered Fibers and Fabrics     Open Access  
Journal of Fashion Technology & Textile Engineering     Hybrid Journal   (Followers: 6)
Journal of Industrial Textiles     Hybrid Journal   (Followers: 4)
Journal of Leather Science and Engineering     Open Access  
Journal of Natural Fibers     Hybrid Journal   (Followers: 6)
Journal of Textile Design Research and Practice     Full-text available via subscription   (Followers: 7)
Journal of Textile Science & Engineering     Open Access   (Followers: 3)
Journal of Textiles and Fibrous Materials     Full-text available via subscription   (Followers: 1)
Journal of The Institution of Engineers (India) : Series E     Hybrid Journal   (Followers: 2)
Journal of the Textile Institute     Hybrid Journal   (Followers: 7)
Research Journal of Textile and Apparel     Full-text available via subscription   (Followers: 4)
Text and Performance Quarterly     Hybrid Journal   (Followers: 5)
Textile History     Hybrid Journal   (Followers: 15)
Textile Progress     Hybrid Journal   (Followers: 3)
Textile Research Journal     Hybrid Journal   (Followers: 11)
Third Text     Hybrid Journal   (Followers: 13)
Wearables     Open Access   (Followers: 1)
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Fibers
Number of Followers: 4  

  This is an Open Access Journal Open Access journal
ISSN (Online) 2079-6439
Published by MDPI Homepage  [258 journals]
  • Fibers, Vol. 11, Pages 48: Multimode Graded Index Fiber with Random Array
           of Bragg Gratings and Its Raman Lasing Properties

    • Authors: Alexey G. Kuznetsov, Alexey A. Wolf, Zhibzema E. Munkueva, Alexander V. Dostovalov, Sergey A. Babin
      First page: 48
      Abstract: Light propagation in multimode fibers is known to experience various nonlinear effects, which are being actively studied. One of the interesting effects is the brightness enhancement at the Raman conversion of the multimode beam in graded index (GRIN) fiber due to beam cleanup at Raman amplification and mode selective feedback in the Raman laser cavity based on fiber Bragg gratings (FBGs) with special transverse structure. It is also possible to explore random distributed feedback based on Rayleigh backscattering on natural refractive index fluctuations in GRIN fibers, but it is rather weak, requiring very high power multimode pumping for random lasing. Here, we report on the first realization of femtosecond pulse-inscribed arrays of weak randomly spaced FBGs in GRIN fibers and study Raman lasing at its direct pumping by highly multimode (M2~34) 940-nm laser diodes. The fabricated 1D–3D FBG arrays are used as a complex output mirror, together with the highly reflective input FBG in 1-km fiber. Above threshold pump power (~100 W), random lasing of the Stokes beam at 976 nm is obtained with output power exceeding 28 W at 174 W pumping. The beam quality parameter varies for different arrays, reaching M2~2 at the linewidth narrowing to 0.1–0.2 nm due to the interference effects, with the best characteristics for the 2D array.
      Citation: Fibers
      PubDate: 2023-05-24
      DOI: 10.3390/fib11060048
      Issue No: Vol. 11, No. 6 (2023)
       
  • Fibers, Vol. 11, Pages 36: Effective Strengthening of RC Beams Using
           Bamboo-Fibre-Reinforced Polymer: A Finite-Element Analysis

    • Authors: Jia Ning Siew, Qi Yan Tan, Kar Sing Lim, Jolius Gimbun, Kong Fah Tee, Siew Choo Chin
      First page: 36
      Abstract: This paper presents a finite-element model of the structural behaviour of reinforced concrete (RC) beams with and without openings externally strengthened with bamboo-fibre-reinforced composite (BFRC) plates. The simulation was performed using ABAQUS Unified FEA 2021HF8 software. The stress–strain relationship of the RC was modelled using a model code for concrete structures, whereas the concrete-damaged plasticity model was used to simulate concrete damage. The predicted crack pattern of the beams was comparable to that from experimental observations. The ultimate load-bearing capacity of RC beams in flexure was predicted with an error of up to 1.50%, while the ultimate load-bearing capacity of RC beams with openings in shear was predicted with an error ranging from 1.89 to 13.43%. The most successful arrangement for strengthening a beam with openings in the shear zone was to place BFRC plates perpendicular to the crack on both sides of the beam’s surface, which increased the beam’s original load-bearing capacity by 110.06% compared to that of the control beam (CB). The most effective method for strengthening RC beams in flexure is to attach a BFRC plate to the entire bottom soffit of the RC beam. This maximises the ultimate load-bearing capacity at the expense of the beam’s ductility.
      Citation: Fibers
      PubDate: 2023-04-22
      DOI: 10.3390/fib11050036
      Issue No: Vol. 11, No. 5 (2023)
       
  • Fibers, Vol. 11, Pages 37: Shear Strength Prediction of
           Steel-Fiber-Reinforced Concrete Beams Using the M5P Model

    • Authors: Nadia Moneem Al-Abdaly, Mahdi J. Hussein, Hamza Imran, Sadiq N. Henedy, Luís Filipe Almeida Bernardo, Zainab Al-Khafaji
      First page: 37
      Abstract: This article presents a mathematical model developed using the M5P tree to predict the shear strength of steel-fiber-reinforced concrete (SFRC) for slender beams using soft computing techniques. This method is becoming increasingly popular for addressing complex technical problems. Other approaches, such as semi-empirical equations, can show known inaccuracies, and some soft computing methods may not produce predictive equations. The model was trained and tested using 332 samples from an experimental database found in the previous literature, and it takes into account independent variables such as the effective depth d, beam width bw, longitudinal reinforcement ratio ρ, concrete compressive strength fc, shear span to effective depth ratio a/d, and steel fiber factor Fsf. The predictive performance of the proposed M5P-based model was also compared with the one of existing models proposed in the previous literature. The evaluation revealed that the M5P-based model provided a more consistent and accurate prediction of the actual strength compared to the existing models, achieving an R2 value of 0.969 and an RMSE value of 37.307 for the testing dataset. It was found to be a reliable and also straightforward model. The proposed model is likely to be highly helpful in assessing the shear capacity of SFRC beams during the pre-planning and pre-design stages and could also be useful to help for future revisions of design standards.
      Citation: Fibers
      PubDate: 2023-04-27
      DOI: 10.3390/fib11050037
      Issue No: Vol. 11, No. 5 (2023)
       
  • Fibers, Vol. 11, Pages 38: Production of Long Hemp Fibers Using the Flax
           Value Chain

    • Authors: Lola Pinsard, Nathalie Revol, Henri Pomikal, Emmanuel De Luycker, Pierre Ouagne
      First page: 38
      Abstract: Hemp is finding a strong renewal of interest in the production of fine fibers for garment textiles. This resource of long-line fibers would come as a complement to the highly demanded flax fibers, whose large production in the north-west of Europe cannot be extended. In Normandy, where a complete industrial value chain exists for flax, it is intended to adapt it to hemp, and this was demonstrated from the field to the scutched fibers with a complete value chain. In this region, early harvesting is necessary to leave enough time for dew-retting and permit dry storage of stems before mid-September. An early-flowering variety (USO-31) was harvested using dedicated hemp equipment to obtain a 1 m parallel and aligned windrow that can be further processed by flax equipment. The scutching process as well as the fiber’s morphological and mechanical properties were particularly studied. Adapted scutching process parameters with reduced advancing speed and beating turbine velocity led to long fiber yields of about 18% of the stem mass. Stem yields were reaching about 6 tons/ha leading to a production of 1.1 tons/ha of long fibers. The tensile properties of the long fibers were highly sufficient for textile applications, and their thickness after hackling was in the range suitable for the production of fine yarns. Compared to other crops grown in Normandy, the hemp as produced in this 2020 case study provides good incomes to the farmer, higher than traditional crops such as wheat or barley, and the results of this study should encourage farmers to grow hemp for textile purposes.
      Citation: Fibers
      PubDate: 2023-04-28
      DOI: 10.3390/fib11050038
      Issue No: Vol. 11, No. 5 (2023)
       
  • Fibers, Vol. 11, Pages 39: Mechanical Properties and Morphological
           Alterations in Fiber-Based Scaffolds Affecting Tissue Engineering Outcomes
           

    • Authors: James Dolgin, Samerender Nagam Hanumantharao, Stephen Farias, Carl G. Simon, Smitha Rao
      First page: 39
      Abstract: Electrospinning is a versatile tool used to produce highly customizable nonwoven nanofiber mats of various fiber diameters, pore sizes, and alignment. It is possible to create electrospun mats from synthetic polymers, biobased polymers, and combinations thereof. The post-processing of the end products can occur in many ways, such as cross-linking, enzyme linking, and thermal curing, to achieve enhanced chemical and physical properties. Such multi-factor tunability is very promising in applications such as tissue engineering, 3D organs/organoids, and cell differentiation. While the established methods involve the use of soluble small molecules, growth factors, stereolithography, and micro-patterning, electrospinning involves an inexpensive, labor un-intensive, and highly scalable approach to using environmental cues, to promote and guide cell proliferation, migration, and differentiation. By influencing cell morphology, mechanosensing, and intracellular communication, nanofibers can affect the fate of cells in a multitude of ways. Ultimately, nanofibers may have the potential to precisely form whole organs for tissue engineering, regenerative medicine, and cellular agriculture, as well as to create in vitro microenvironments. In this review, the focus will be on the mechanical and physical characteristics such as porosity, fiber diameter, crystallinity, mechanical strength, alignment, and topography of the nanofiber scaffolds, and the impact on cell proliferation, migration, and differentiation.
      Citation: Fibers
      PubDate: 2023-04-29
      DOI: 10.3390/fib11050039
      Issue No: Vol. 11, No. 5 (2023)
       
  • Fibers, Vol. 11, Pages 40: A Review of Fibre Reinforced Polymer Bridges

    • Authors: Jawed Qureshi
      First page: 40
      Abstract: Fibre-reinforced polymer composites (FRPs) offer various benefits for bridge construction. Lightweight, durability, design flexibility and fast erection in inaccessible areas are their unique selling points for bridge engineering. FRPs are used in four bridge applications: (1) FRP rebars/tendons in concrete; (2) repair and strengthening of existing bridges; (3) new hybrid–FRP bridges with conventional materials and (4) all–FRP composite new bridges made entirely of FRP materials. This paper reviews FRP bridges, including all–FRP and hybrid–FRP bridges. FRP bridges’ history, materials, processes and bridge components—deck, girder, truss, moulded parts and cables/rebars are considered. This paper does not discuss the use of FRP as an architectural element and a strengthening system. While lack of design codes, material specifications and recycling are the major challenges, the high cost of FRPs still remains the most critical barrier to the progress of FRPs in bridges.
      Citation: Fibers
      PubDate: 2023-05-04
      DOI: 10.3390/fib11050040
      Issue No: Vol. 11, No. 5 (2023)
       
  • Fibers, Vol. 11, Pages 41: On the Pressure and Rate of Infiltration Made
           by a Carbon Fiber Yarn with an Aluminum Melt during Ultrasonic Treatment

    • Authors: Sergei Galyshev, Bulat Atanov, Valery Orlov
      First page: 41
      Abstract: The effect of the infiltration time of a carbon fiber yarn in the range of 6 to 13.6 s on the infiltrated volume under the cavitation of an aluminum melt has been studied. When the infiltration time was more than 10 s, the carbon fiber was completely infiltrated with the matrix melt, and a decrease in the infiltration time led to a monotonous decrease in the fraction of the infiltrated volume. Based on the experimental data, the infiltration rate and the pressure necessary to infiltrate a carbon fiber yarn with an aluminum melt were estimated. The infiltration rate was 20.9 cm3/s and was independent of the infiltration depth. The calculated pressure necessary for the complete infiltration of a carbon fiber yarn at this rate was about 270 Pa. A comparison of the pressure values calculated according to Darcy’s and Forchheimer’s laws showed that the difference between them did not exceed 0.01%. This indicates that a simpler Darcy’s law could be used to estimate pressure.
      Citation: Fibers
      PubDate: 2023-05-06
      DOI: 10.3390/fib11050041
      Issue No: Vol. 11, No. 5 (2023)
       
  • Fibers, Vol. 11, Pages 42: Performance of Rice Straw Fibers on Hardened
           Concrete Properties under Effect of Impact Load and Gamma Radiation

    • Authors: Mohamed M. Mahdy, Sameh Y. Mahfouz, Ahmed F. Tawfic, Mohamed A. E. M. Ali
      First page: 42
      Abstract: Concrete is an essential artificial building material in modern society. However, because concrete structures have brittle characteristics, they have a limited service life when subjected to dynamic loads. Nuclear emissions and explosions threaten human lives and structures’ safety due to harmful radiation and dynamic effects. Since agriculture has revealed a large amount of by-products that require disposal, the use of such by-products in many sectors is a challenge for contemporary studies. One of the most important areas for the disposal of such waste is construction, and concrete in particular. The utilization of the agricultural by-product rice straw fiber was chosen in this study to replace the usage of artificial fibers in concrete production and present an eco-friendly prospective contender with enhanced static/dynamic performance and gamma shielding characteristics. Different concrete mixtures were proposed in this study to evaluate the aforementioned characteristics. The designed concrete mixtures were conventional concrete with variations in the volume fraction of rice straw fibers (RSF) of 0%, 0.25%, 0.5%, and 0.75%. The desired static properties were compressive strength, splitting tensile strength, and flexural strength. Additionally, the drop weight impact test was used in this study to investigate the impact resistance of RSF-reinforced concrete. Finally, the radiation-shielding characteristic of the produced concrete was tested using the linear attenuation test. The results show that adding agricultural by-products of RSF in concrete production slightly enhanced the compressive strength by up to 7.0%, while it significantly improved the tensile and flexural properties by up to 17.1% and 25.8%, respectively. Additionally, a superior impact resistance of concrete was achieved by up to 48.6% owing to RSF addition. Furthermore, it enhanced the gamma shielding capability of concrete by up to 7.9%. The achievements in this study pave the way for utilizing RSF-reinforced concrete in various non-traditional applications.
      Citation: Fibers
      PubDate: 2023-05-08
      DOI: 10.3390/fib11050042
      Issue No: Vol. 11, No. 5 (2023)
       
  • Fibers, Vol. 11, Pages 43: Targeted Pre-Treatment of Hemp Fibers and the
           Effect on Mechanical Properties of Polymer Composites

    • Authors: K. Palanikumar, Elango Natarajan, Kalaimani Markandan, Chun Kit Ang, Gérald Franz
      First page: 43
      Abstract: Research on plant-fiber-reinforced composites has gained significant research interest since it generates composites with exceptional mechanical properties; however, the potential of hemp fibers can only be fully exploited if the fibers are well separated from the bundle to achieve cellulose-rich fibers. This is because well-separated bast fibers that are long and exhibit higher fiber aspect ratio enhance the mechanical properties of the composite by influencing property translations upon loading. A key feature for successful implementation of natural fibers is to selectively remove non-cellulosic components of hemp fiber to yield cellulose-rich fibers with minimal defects. Targeted pre-treatment techniques have been commonly used to address the aforementioned concerns by optimizing properties on the fiber’s surface. This in turn improves interfacial bonding between the fibers and the hydrophobic polymer, enhances the robustness of hemp fibers by improving their thermal stability and increases resistance to microbial degradation. In this study, we comprehensively review the targeted pre-treatment techniques of hemp fiber and the effect of hemp fiber as a reinforcement on the mechanical properties of polymeric composites.
      Citation: Fibers
      PubDate: 2023-05-09
      DOI: 10.3390/fib11050043
      Issue No: Vol. 11, No. 5 (2023)
       
  • Fibers, Vol. 11, Pages 44: Advanced Study of Columns Confined by
           Ultra-High-Performance Concrete and Ultra-High-Performance
           Fiber-Reinforced Concrete Confinements

    • Authors: Rr. M. I. Retno Susilorini, Yuliarti Kusumawardaningsih
      First page: 44
      Abstract: The need for concrete with ‘super’ strength and ‘super’ ductility for greater sustainability has been answered by the existence of ultra-high-performance concrete (UHPC) and ultra-high-performance fiber-reinforced concrete (UHPFRC). Over the last decades, UHPFRC has been implemented in actual concrete structures, as well as used to retrofit structural elements, including columns. However, the use of UHPC and UHPFRC confinement to strengthen normal concrete columns is still limited. Therefore, this research aims to investigate the advanced performance of columns using UHPC and UHPFRC confinement in the context of the strength and ductility of such columns, such as load capacity, stress–strain behavior, and the crack pattern in the failure mode. This research is an advanced study of several investigations previously carried out by other authors on the characteristics of UHPC and UHPFRC, as well as columns confined by UHPC and UHPFRC. The methods used in this research are experimental and analytical. The experimental results were compared to analytical calculations for validation. This research produced 12 short-column specimens confined by UHPC (CF0 series) and UHPFRC (CF1 and CF2 series) that contained 0%, 1%, and 2% fiber and were also tested for axial loading and various eccentricities as follows: e = 0, 35, and 70 mm. The results found that the normal strength concrete (NSC) columns confined by UHPC and UHPFRC could sustain a higher maximum load and stress, and also sustain greater vertical deformation and strain compared to the control specimens. It was noted that specimen CF2-35 had the highest load capacity, vertical deformation, maximum stress, and maximum vertical strain compared to specimen C-0 (control column with no confinement). The specimen CF2-35 (column confined by UHPC with a 2% fiber volume with an eccentricity of 35 mm) also exhibited a ductile failure mode and very minor cracks. It was also found that 75% of the specimens had 0–39% errors and 25% had 0–13% errors. The research proved that the addition of a volume of 2% fiber to the UHPFRC minimizes the crack of the failure mode and prevents confinement spalling of the column. This research has led to the conclusion that UHPC and UHPFRC confinements will increase the strength and ductility of columns.
      Citation: Fibers
      PubDate: 2023-05-10
      DOI: 10.3390/fib11050044
      Issue No: Vol. 11, No. 5 (2023)
       
  • Fibers, Vol. 11, Pages 45: Elementary Liber Fibres Characterisation: Bias
           from the Noncylindricity and Morphological Evolution along the Fibre

    • Authors: Marie Grégoire, Emmanuel De Luycker, Pierre Ouagne
      First page: 45
      Abstract: In this work, we investigate the influence of noncircularity along with cross-sectional area evolution on the measurement of the mechanical properties of elementary fibres. First, we focus on the cross-sectional area measurement and compare the circular assumption with the elliptical one using an ombroscopic device that allows the measurement of the projected diameters along the fibre as the fibre rotates around its axis, the fibre dimensional analysis system (FDAS). The results highlight important approximations to the cross-sectional area evaluation for fibres with noncircular cross sections, leading to reduced elastic modulus and stress at failure evaluated by the standard method. Additionally, results from the FDAS are used to evaluate the twist inside an individual fibre when the cross sections are sufficiently elliptical. A numerical model based on the real measured dimensions of the fibres is developed to illustrate and visualize this nonuniformity and to more accurately identify the elastic modulus. The results obtained lead us to an analytical approach that takes into account the evolution of the cross-sectional area along the fibre for a better identification of the stiffness and modulus of elasticity, which maximizes the identified mechanical properties on average by 12% for the modulus and 200% for the stress at failure. Finally, recommendations are formulated to better account for the variability along a fibre in order to evaluate the cross-sectional area.
      Citation: Fibers
      PubDate: 2023-05-15
      DOI: 10.3390/fib11050045
      Issue No: Vol. 11, No. 5 (2023)
       
  • Fibers, Vol. 11, Pages 46: High-Temperature Behavior of
           Polyethylene-Terephthalate-Fiber-Reinforced Sand Concrete: Experimental
           Investigation

    • Authors: Mohammed Benzerara, Yasmina Biskri, Messaoud Saidani, Fayçal Slimani, Redjem Belouettar
      First page: 46
      Abstract: At ambient temperature, concrete exhibits excellent mechanical properties. However, understanding the behavior of concrete under high-temperature conditions is crucial, especially for civil engineering applications during fire incidents. The growing use of plastic-based products has led to a significant increase in polymer waste, posing environmental challenges. The valorization of this plastic waste in the form of fibers presents both economic and environmental advantages. This study focuses on the study of the behavior of sand concrete incorporating polyethylene terephthalate (PET) fibers with percentages of 1% and 2% at high temperatures (100, 300, 500 and 700 °C). Specimens are tested for residual mass loss, residual compressive and tensile strength. A complementary analysis of SEM makes it possible to confirm and better clarify the morphology of the concretes of sand before and after the rise in temperature. The results obtained from this study indicate that the residual resistance is reduced with the rise in temperature for all the concretes studied, except in the temperature range of 300 °C, in which a slight improvement in resistance is noticed. The incorporation of PET fibers in the test concretes does not enhance their residual behavior significantly. However, it does serve as an effective solution by reducing the susceptibility to spalling, by preventing cracking and by fulfilling a similar role to that of polypropylene fibers.
      Citation: Fibers
      PubDate: 2023-05-16
      DOI: 10.3390/fib11050046
      Issue No: Vol. 11, No. 5 (2023)
       
  • Fibers, Vol. 11, Pages 47: The Exothermic Effects of Textile Fibers during
           Changes in Environmental Humidity: A Comparison between ISO:16533 and
           Dynamic Hot Plate Test Method

    • Authors: Faisal Abedin, Emiel DenHartog
      First page: 47
      Abstract: The exothermic effects of high regain fiber types have been described before; yet, there have not been reliable tests to demonstrate these effects on the human body. Most test methods focus on steady-state measurements; therefore, these exothermic effects during changes in environmental humidity are typically not analyzed or quantified. We have conducted a set of fabric tests that shows the connection between the exothermic effect of water vapor uptake and its consequence for heat loss through the fabric in transient conditions. We have performed the ISO:16533 standard test, a dynamic hot plate test developed by Naylor to measure the exothermic property of the fabric, and dynamic regain tests to connect the dots between these tests and the water vapor uptake phenomenon. Although the ISO:16533 test method tends to show the temperature increase in fibers, it cannot differentiate between the hygroscopic fiber (wool, viscose, cotton) types (p > 0.001). In addition, sensor size and sample folding techniques could impact the temperature increase. On the other hand, the Naylor hot plate test showed a greater difference in heat release among the fiber types (wool showed 20% higher heat release than viscose, 50% more than cotton), although the relative humidity changes in the chamber take time, which might not reflect a step-wise change in humidity. So far, these test methods have proven to be the most reliable for determining the exothermic behavior of textile fiber. However, these test methods still have limitations and cannot simulate realistic environmental conditions considering an instantaneous change in the environment. This paper reflects the comparison between the two test methods and recommends directions to accurately address the theory of water vapor uptake under dynamic conditions.
      Citation: Fibers
      PubDate: 2023-05-22
      DOI: 10.3390/fib11050047
      Issue No: Vol. 11, No. 5 (2023)
       
  • Fibers, Vol. 11, Pages 31: Effect of Elevated Temperature on the Behavior
           of Amorphous Metallic Fibre-Reinforced Cement and Geopolymer Composites

    • Authors: Faiz Uddin Ahmed Shaikh, Narwinder Singh Kahlon, Attiq Ur Rahman Dogar
      First page: 31
      Abstract: To improve the tensile, flexural, and ductility properties of geopolymer composites, amorphous metallic fibres (AMF) are used to reinforce these composites, and the behavior of these composites at elevated temperatures has been assessed in this study. Four types of composites, i.e., cement, reinforced cement, geopolymer, and reinforced geopolymer composites have been prepared. The composites have been reinforced using AMF with a fibre volume fraction of 0.75%. The composites have been assessed for change in mass loss, cracking, compressive strength, and flexural strength at four elevated temperatures of 200 °C, 400 °C, 600 °C, and 800 °C, and conclusions have been drawn concerning these composites. The results have shown that an increase in temperature has an adverse effect on these composites, and geopolymer composites exhibit higher performance than their counterpart cement composites at elevated temperatures. The mass loss and surface cracking were significantly lower in geopolymer composites, and the fibre reinforcement had a negligible effect on mass loss. Also, the residual compressive and flexural strength of reinforced geopolymer composites was significantly higher than that of the reinforced cement composites. In addition, scanning electron microscopic images also showed that even at higher temperatures, the geopolymer matrix is present on the AMF fibre, which results in higher residual strength than the cement composites in which a negligible amount of matrix is present on the fibres.
      Citation: Fibers
      PubDate: 2023-03-28
      DOI: 10.3390/fib11040031
      Issue No: Vol. 11, No. 4 (2023)
       
  • Fibers, Vol. 11, Pages 32: Adsorption Studies of Ammonia, Protein, and
           

    • Authors: Duangkamol Dechojarassri, Kensuke Nishida, Ryousuke Ozakiya, Tetsuya Furuike, Hiroshi Tamura
      First page: 32
      Abstract: Herein, chitosan (CS) fibers coated with TEMPO-oxidized cellulose nanofibers (CS/TOCN fibers) were successfully prepared using a wet spinning technique; CS was dissolved in acetic acid to obtain a CS doping solution. The tensile strength and ammonia adsorption percentages increased with increasing TOCN concentration. The maximum ammonia adsorption percentage (41.39%, 8.3 mg/g) was obtained when 2% NaOH and 0.01% TOCN were used as the coagulation solution. Additionally, the adsorption of model proteins, including lysozyme (Lz), cytochrome C (Cyt C), and bovine serum albumin (BSA), were studied. In water, the CS/TOCN fibers with negative charges adsorbed more Lz with positive charges than CS fibers containing positive charges. Contrastingly, CS fibers adsorbed more Cyt C and BSA containing negative charges in phosphate-buffered saline solutions than CS/TOCN fibers. Furthermore, the adsorption percentage of phytic acid using the CS/TOCN fibers reached 64.18% (288 mg/g) within 60 min. Thus, TOCNs improved the tensile properties of CS fibers and preferred positively charged materials contaminated in water, such as ammonia, Lz, and phytic acid.
      Citation: Fibers
      PubDate: 2023-03-30
      DOI: 10.3390/fib11040032
      Issue No: Vol. 11, No. 4 (2023)
       
  • Fibers, Vol. 11, Pages 33: Improving the Physical and Mechanical
           Characteristics of Modified Aerated Concrete by Reinforcing with Plant
           Fibers

    • Authors: Alexey N. Beskopylny, Evgenii M. Shcherban’, Sergey A. Stel’makh, Levon R. Mailyan, Besarion Meskhi, Alexandr Evtushenko, Diana El’shaeva, Andrei Chernil’nik
      First page: 33
      Abstract: An urgent and promising direction in the development of building materials science is the improvement of the quality of non-autoclaved aerated concrete. In view of the obvious disadvantages of non-autoclaved aerated concrete compared to the autoclaved equivalent in terms of technology, it can be significantly improved because of a rationally selected composition and other factors of a recipe-technological nature. The goal of the study was to search for complex compositions and technological solutions aimed at identifying rational combinations of recipe-technological factors as simultaneous modifications of aerated concrete with various additives and dispersed the reinforcement of it with various environmentally friendly and cost-effective types of plant fibers. Fly ash (FA), instead of part of the cement, proved to be more effective than the GGBS additive. The compressive strength (CS), bending strength (BS), and coefficient of construction quality (CCQ) were higher by 4.5%, 3.8%, and 1.7%, respectively, while the density and thermal conductivity (TC) were lower by 0.7% and 3.6%, respectively, compared with aerated concrete modified with ground granulated blast-furnace slag (GGBS). The additional reinforcement of modified aerated concrete with coconut fiber (CF) and sisal fiber (SF) in an amount of 0.6% of the total mass of cement and modifier increases the CS to 15%, BS to 22% and CCQ to 16%. The SF was more effective than the CF. Aerated concrete modified with FA and reinforced with SF showed the highest efficiency. Compared to the control composition without modifiers or fibers, the increase in the CS was up to 40%, BS up to 47%, and CCQ up to 43%, while the decrease in density was up to 2.6%, and TC up to 15%.
      Citation: Fibers
      PubDate: 2023-04-03
      DOI: 10.3390/fib11040033
      Issue No: Vol. 11, No. 4 (2023)
       
  • Fibers, Vol. 11, Pages 34: An Electromechanical Impedance-Based
           Application of Realtime Monitoring for the Load-Induced Flexural Stress
           and Damage in Fiber-Reinforced Concrete

    • Authors: Maria C. Naoum, George M. Sapidis, Nikos A. Papadopoulos, Maristella E. Voutetaki
      First page: 34
      Abstract: Effective real-time structural health monitoring in concrete structures is paramount to evaluating safety conditions and the timely maintenance of concrete structures. Especially, the presence of discrete fibers in fiber-reinforced concrete restrains crack propagation into small and thin cracks, which increases the difficulty in detecting damage. In this study, an array of piezoelectric lead zirconate titanate (PZT) transducers was applied to study the effects of external load-induced flexural stress and damage in fiber-reinforced concrete beams using the electromechanical impedance (EMI) or electromechanical admittance (EMA) methods. Beams were subjected to a four-point bending test under repeatable loading, while PZTs evaluated corresponding flexural stress and induced damage simultaneously. Due to the influence of the medium’s stress fields in the different types of wave propagation in structural elements, PZT transducers measurements are accordingly affected under variable stress fields, in addition to the effect of the higher level of damage that occurred in the medium. According to the results of the tests, variation in EMA signatures, following flexural stress and gradual damage changes, provided convincing evidence for predicting stress and damage development.
      Citation: Fibers
      PubDate: 2023-04-11
      DOI: 10.3390/fib11040034
      Issue No: Vol. 11, No. 4 (2023)
       
  • Fibers, Vol. 11, Pages 35: Shear Strengthening and Repairing of Reinforced
           Concrete Deep Beams Damaged by Heat Using NSM–CFRP Ropes

    • Authors: Ahmad Al-khreisat, Mu’tasime Abdel-Jaber, Ahmed Ashteyat
      First page: 35
      Abstract: This study investigates experimentally the shear strengthening and repairing of reinforced concrete (RC) deep beams damaged by heat utilizing near-surface mounted carbon fiber reinforced polymers (NSM-CFRP) ropes. The main parameters adopted in this research are rope orientation (45°, 90°) and rope spacing (150 mm, 200 mm). For this purpose, ten RC deep beams were cast and tested until failure was reached. The test results showed that using NSM-CFRP ropes with various configurations significantly enhanced the shear capacity for repaired and strengthened deep beams. All the tested beams enhanced the ultimate load capacity for the strengthened beams ranging between 19% to 46%, while for the repaired beams, the values ranged between 40.8% to 64.6%. The CFRP ropes oriented at 45° recorded the highest enhancement result in shear capacity. Notably, all tested beams had a satisfactory rise in the enhancement ratio. Consequently, the economic aspect should have priority.
      Citation: Fibers
      PubDate: 2023-04-13
      DOI: 10.3390/fib11040035
      Issue No: Vol. 11, No. 4 (2023)
       
  • Fibers, Vol. 11, Pages 23: Synergistic Effect of HEDP.4Na and Different
           Induced Pouring Angles on Mechanical Properties of Fiber-Reinforced
           Alkali-Activated Slag Composites

    • Authors: Jingjie Wei, Jianwei Liu, Kamal H. Khayat, Wu-Jian Long
      First page: 23
      Abstract: The poor flexural and damping properties of building materials damages concrete structures and affects their service life when concrete structures are subjected to dynamic loads. Three different dosages (i.e., 0%, 0.3%, and 0.6%) of organic phosphonates (HEDP.4Na) and different pouring methods (i.e., conventional pouring method, 90°-induced pouring method, and 150°-induced pouring method) were designed to improve the flexural and damping performance of fiber-reinforced alkali-activated slag composites (FR-AASC). The enhanced mechanism of HEDP.4Na was revealed by phase analysis (X-ray diffraction, XRD), pore structure analysis (Mercury Intrusion Porosimetry, MIP), the heat of hydration, and scanning electron microscopy (SEM) analysis. The results showed that 0.3% HEDP.4Na combined with the 150°-induced pouring angle can significantly improve the mechanical properties of the FR-AASC sample compared with the reference group. The sample with 0.3% HEDP.4Na cast by the 150°-induced pouring angle increased compressive and flexural strength, damping energy consumption and storage modulus by 20%, 60%, 78%, and 30%, respectively, compared with the reference sample cast by the conventional pouring methodology. HEDP.4Na reduced the early hydration heat and total porosity of the FR-AASC matrix, modified the fiber–matrix interface transition zone, and increased the frictional energy consumption of steel fibers. Overall, the synergistic effect of HEDP.4Na and the induced pouring methodology significantly improved the flexural and damping properties of FR-AASC. This study can provide a guidance for improving the flexural and damping capacity of FR-AASC and promote the application of FR-AASC in construction engineering.
      Citation: Fibers
      PubDate: 2023-02-22
      DOI: 10.3390/fib11030023
      Issue No: Vol. 11, No. 3 (2023)
       
  • Fibers, Vol. 11, Pages 24: Application of Transformed Cross-Section Method
           for Analytical Analysis of Laminated Veneer Lumber Beams Strengthened with
           Composite Materials

    • Authors: Michał Marcin Bakalarz, Paweł Grzegorz Kossakowski
      First page: 24
      Abstract: Due to the high cost of laboratory testing, many researchers are considering developing methods to predict the behavior of unreinforced and reinforced wood beams. This work aims to create either numerical or analytical models useful for extrapolating already conducted tests to other schemes/materials used as reinforcement. In the case of timber structures, due to the complexity of timber, this task is difficult. The first part of the article presents an analysis of the suitability of using a simplified mathematical model based on the equivalent cross-section method to describe the behavior of unreinforced and reinforced with carbon-fibre-reinforced polymer (CFRP) composite full-size laminated veneer lumber (LVL) beams. The theoretical results were compared with the results of conducted experimental tests. The scope of the analysis includes the estimation of modulus of rupture, bending stiffness, and determination of the neutral axis position. The equivalent cross-section method showed good agreement in determining the bending stiffness and neutral axis position of the strengthened sections. However, the suitability of using the equivalent cross-section method to estimate the load-carrying capacity of a cross-section reinforced with fiber composites still needs to be confirmed, which, according to the authors, is due to the differences between the assumed (linear) and actual (nonlinear) strain distribution in the compression zone. The second part uses the equivalent cross-section method to estimate the predicted bending stiffness of LVL beams strengthened with aramid-fibre-reinforced polymer (AFRP), glass-fibre-reinforced polymer (GFRP), and ultra-high modulus carbon-fibre-reinforced polymer (CFRP UHM) sheets. The proposed method can be used for preliminary evaluation of strengthening effectiveness of LVL beams.
      Citation: Fibers
      PubDate: 2023-02-23
      DOI: 10.3390/fib11030024
      Issue No: Vol. 11, No. 3 (2023)
       
  • Fibers, Vol. 11, Pages 25: Engineering Properties of Waste Badminton
           String Fiber

    • Authors: Kumaresan M, S Sindhu Nachiar, Anandh Sekar
      First page: 25
      Abstract: This work addresses the feasibility of using waste badminton string fiber in cement and polymer matrices. A badminton racquet, once used, is torn and needs replacement with new strings. These torn strings, once cut from the badminton racquet system, become waste, and these fibers cannot be recycled and remain debris. Hence, this study examines the microstructural and mechanical properties of new fibers and old torn fibers comparatively. Scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and energy dispersive spectroscopy are used to study the microstructural properties of the fiber. Direct tensile stress is applied to new and old fibers in the universal testing machine varying by one, three, and five strands of the fibers and varying the gauge length to 60, 80, and 100 mm, and the respective energy absorption is calculated. From investigation with a varying number of strands, similar results were observed in both old and new fibers from energy absorption and residual force ratio. From investigation with varying gauge length, the tensile stress of new fibers varies between 648.53 and 749.03 MPa, and that of old fibers is 537.40–625.55 MPa. Young’s modulus for new and old fibers is 4870.00 and 4843.50 MPa, respectively. The Weibull statistical approach is used to test the variability of test results. The Weibull modulus varies between 5.27 and 9.17, which shows lower variability. Thus, the tensile stress results obtained for the discarded badminton fibers pave way for incorporating these fibers in cement and polymer matrices to improve the matrix properties.
      Citation: Fibers
      PubDate: 2023-03-03
      DOI: 10.3390/fib11030025
      Issue No: Vol. 11, No. 3 (2023)
       
  • Fibers, Vol. 11, Pages 26: Simulation of Acoustic Properties of Plaster
           Matrix Composite MATERIAL Reinforced with Corn Stem Fibers

    • Authors: Virginia Puyana-Romero, Wilson Andrés Jaramillo Cevallos, Giuseppe Ciaburro
      First page: 26
      Abstract: Environmental sustainability and environmental protection are key to shaping the built environment. The use of environmentally sustainable materials in architecture is essential to transform urban centers into modern, sustainable cities, reducing the pollution of air and natural ecosystems, lowering gas emissions, and improving the energy efficiency of structures. In this study, corn processing waste was used as a reinforcing material to create a plaster matrix composite material for use as a sound absorption material. Specimens of two thicknesses were created, and the sound absorption coefficient (SAC) was measured by applying the normal incidence technique. Subsequently, a simulation model for predicting SAC using Artificial Neural Network (ANN) algorithms was utilized to compare the absorption performance of the specimens. The fibers extracted from the corn stem significantly improved the sound absorption performance of the gypsum matrix specimens. This is due to the increase in the porosity of the material caused by the adhesion between the fiber and the plaster which creates air pockets due to the roughness of the fiber. The simulation model appears to be effective in predicting the absorption properties of the material, as indicated by the results.
      Citation: Fibers
      PubDate: 2023-03-04
      DOI: 10.3390/fib11030026
      Issue No: Vol. 11, No. 3 (2023)
       
  • Fibers, Vol. 11, Pages 27: Comparative Study of Atmosphere Effect on Wood
           Torrefaction

    • Authors: Rafael Lopes Quirino, Larissa Richa, Anelie Petrissans, Priscila Rios Teixeira, George Durrell, Allen Hulette, Baptiste Colin, Mathieu Petrissans
      First page: 27
      Abstract: Climate change, biomass utilization, and bioenergy recovery are among the biggest current global concerns. Wood is considered an environmentally benign material. Nevertheless, it must be processed for desired applications. Upon thermal treatment ranging from 180 °C to 280 °C, under low oxygen concentrations, wood becomes a material with improved dimensional stability, resistance to fungal attacks, grindability, hydrophobicity, and storage stability. Several strategies for wood treatment have been investigated over the course of the past decades, including the use of steam, nitrogen, smoke, vacuum, water, and hot oil. The goal of this work is to investigate the influence of pressure and atmosphere on the torrefaction of poplar. Through a systematic analysis of poplar wood samples treated under reduced pressures and different atmospheres, while keeping the same heating profile, it was possible to establish that changes observed for mass loss, color change, wood composition (via TGA/DTG analysis), functional groups (via FTIR), elemental analysis, and X-ray diffractograms relate directly to known reaction pathways occurring during torrefaction. Changes observed under reduced pressures have been associated with the relative concentration of oxygen in the reaction atmosphere and to the reduced diffusion times experienced by reactive by-products during the treatment. Conversely, extended diffusion times resulted in more significant changes for reactions carried out under N2, water vapor, and air.
      Citation: Fibers
      PubDate: 2023-03-07
      DOI: 10.3390/fib11030027
      Issue No: Vol. 11, No. 3 (2023)
       
  • Fibers, Vol. 11, Pages 28: Six-Core GeO2-Doped Silica Microstructured
           Optical Fiber with Induced Chirality

    • Authors: Anton V. Bourdine, Vladimir V. Demidov, Konstantin V. Dukelskii, Alexander V. Khokhlov, Egishe V. Ter-Nersesyants, Sergei V. Bureev, Alexandra S. Matrosova, Grigori A. Pchelkin, Artem A. Kuznetsov, Oleg G. Morozov, Ilnur I. Nureev, Airat Zh. Sakhabutdinov, Timur A. Agliullin, Michael V. Dashkov, Alexander S. Evtushenko, Elena S. Zaitseva, Alexander A. Vasilets, Azat R. Gizatulin, Ivan K. Meshkov, Yaseera Ismail, Francesco Petruccione, Ghanshyam Singh, Manish Tiwari, Juan Yin
      First page: 28
      Abstract: This work presents a fabricated silica few-mode microstructured optical fiber (MOF) with a special six GeO2-doped core geometry, an outer diameter of 125 µm (that corresponds to conventional commercially available telecommunication optical fibers), and improved induced twisting up to 500 revolutions per 1 m (under a rotation speed of 1000 revolutions per meter with a drawing speed of ~2 m per minute). The article discusses some technological aspects and issues of manufacturing the above-described twisted MOFs with complicated structures and geometry as GeO2-doped silica supporting elements for them. We present results of some measurements performed for fabricated samples of chiral silica six-GeO2-doped-core few-mode MOFs with various orders of twisting and both step and graded refractive indexes of “cores”. These tests contain research on MOF geometrical parameters, attenuation, and measurements of the far-field laser beam profile.
      Citation: Fibers
      PubDate: 2023-03-07
      DOI: 10.3390/fib11030028
      Issue No: Vol. 11, No. 3 (2023)
       
  • Fibers, Vol. 11, Pages 29: Textile Fabrics as Electromagnetic Shielding
           Materials—A Review of Preparation and Performance

    • Authors: Tomasz Blachowicz, Dariusz Wójcik, Maciej Surma, Mirosław Magnuski, Guido Ehrmann, Andrea Ehrmann
      First page: 29
      Abstract: Shielding of instruments and humans from electromagnetic interference (EMI) has become increasingly important during the last decades due to more and more machines and devices radiating electromagnetic waves. While several applications can use rigid shields, more flexibility is enabled by developing bendable, drapable, ideally even stretchable EMI shielding. Textile fabrics can have these properties, combined with potentially good mechanical properties, depending on the textile structure and the chosen material. On the other hand, the necessary physical properties, especially conductivity and magnetic properties, cannot be taken for granted in normal textile fabrics. These properties have to be added by conductive yarn or layer coatings, integration of conductive or magnetic fibers, producing intrinsically conductive or magnetic fibers, etc. The article gives a critical comparison of the properties of materials typically used for this purpose, such as intrinsically conductive polymers, metal-coated fabrics and metal wires, MXene coatings, MXene fibers, carbon coatings, and fibers. The review concentrates on thematically suitable papers found in the Web of Science and Google Scholar from the last five years and shows that especially MXenes are highly investigated recently due to their high conductivity and EMI shielding effectiveness, while other conductive and magnetic coatings and fibers are nevertheless still interesting for the preparation of EMI shielding textile fabrics.
      Citation: Fibers
      PubDate: 2023-03-15
      DOI: 10.3390/fib11030029
      Issue No: Vol. 11, No. 3 (2023)
       
  • Fibers, Vol. 11, Pages 30: Damage Investigation on the Carbon Tows during
           Rewinding and Braiding Processes

    • Authors: Justine Calba, Damien Soulat, Xavier Legrand, Sébastien Renauld
      First page: 30
      Abstract: During the manufacturing process, the fibrous materials used in composite reinforcements are subjected to many sources of damage that must be managed if the best possible quality is to be reached for the final product. More specifically, carbon fibers are subjected, during reinforcement manufacturing, to friction with mechanical components and with other tows and to excessive tensile loads due to specific configurations required by textile devices, which results in degradation that affects their mechanical properties and those of final products. While many studies have focused on carbon tow damage during the weaving process, roving quality control during the post-braiding steps, such as the rewinding or braiding processes, is less studied in the literature. In this study, an experimental approach was developed to quantify the damage inflicted on 12 K carbon tows during the rewinding and braiding processes using image analysis software. Based on these images, a damage criterion is defined to quantify the influence of the parameters associated with rewinding and braiding processes on degradation of carbon tows. During the rewinding stage, the influence of the process parameters on the degradation by friction of the tows was significant, but the properties (linear density and tenacity) of these carbon tows were little-modified. On the other hand, the great influence of the tension applied on tows on the inflicted damage was experimentally demonstrated, during both the rewinding and braiding steps, which may have resulted in a loss of tenacity of up to 27%.
      Citation: Fibers
      PubDate: 2023-03-22
      DOI: 10.3390/fib11030030
      Issue No: Vol. 11, No. 3 (2023)
       
  • Fibers, Vol. 11, Pages 12: Natural and Sustainable' Consumers’
           Textile Fiber Preferences

    • Authors: Anna Schytte Sigaard, Kirsi Laitala
      First page: 12
      Abstract: Textile fibers have become a major issue in the debate on sustainable fashion and clothing consumption. While consumers are encouraged to choose more sustainable and circular textile materials, studies have indicated that a reduction in production and consumption has the greatest potential to reduce the total environmental impact. This can be considered an ecocentric perspective with a focus on degrowth as opposed to a technocentric view where new technologies are expected to solve environmental problems while economic growth continues. Based on a survey in Norway (N = 1284), we investigate how the techno- and ecocentric perspectives impact Norwegian consumers’ fiber preferences and perceptions and the corresponding effects on their clothing consumption. We found that the majority of consumers preferred natural fibers compared to synthetic materials. This contradicts current market practices and the recommendations by material sustainability comparison tools such as the Higg Material Sustainability Index (MSI), where many synthetics receive better ratings than natural fibers. We also found that perceptions of high sustainability regarding fibers were negatively correlated with reduced consumption. Our study suggests that a continued focus on material substitution and other technological measures for reducing climate change will impede the move toward sustainability in the textile sector.
      Citation: Fibers
      PubDate: 2023-01-26
      DOI: 10.3390/fib11020012
      Issue No: Vol. 11, No. 2 (2023)
       
  • Fibers, Vol. 11, Pages 13: Physical, Chemical, and Mechanical
           Characterization of Natural Bark Fibers (NBFs) Reinforced Polymer
           Composites: A Bibliographic Review

    • Authors: Sivasubramanian Palanisamy, Mayandi Kalimuthu, Rajini Nagarajan, José Maria Fernandes Marlet, Carlo Santulli
      First page: 13
      Abstract: The specific interest for the use of bark in materials, instead than for energy recovery, is owed to circular economy considerations, since bark fibers are normally byproducts or even waste from other sectors, and therefore their use would globally reduce the amount of refuse by replacing other materials in the production of composites. For the purpose of promoting their application in polymer composites, mainly under a geometry of short random fibers, bark fibers are extracted and treated, normally chemically by alkali. Following this, investigations are increasingly carried out on their chemical composition. More specifically, this includes measuring cellulose, hemicellulose, and lignin content and their modification with treatment on their thermal properties and degradation profile, and on the mechanical performance of the fibers and of the tentatively obtained composites. This work aims at reviewing the current state of studies, trying to elicit which bark fibers might be most promising among the potentially enormous number of these, clarifying which of these have received some attention in literature and trying to elicit the reason for this specific interest. These can be more thoroughly characterized for the purpose of further use, also in competition with other fibers not from bark, but from bast, leaves, etc., and pertaining to developed production systems (cotton, hemp, flax, jute, etc.). The latter are already widely employed in the production of composites, a possibility scantly explored so far for bark fibers. However, some initial works on bark fiber composites and both thermoplastic and thermosetting are indicated and the importance of some parameters (aspect ratio, chemical treatment) is discussed.
      Citation: Fibers
      PubDate: 2023-01-28
      DOI: 10.3390/fib11020013
      Issue No: Vol. 11, No. 2 (2023)
       
  • Fibers, Vol. 11, Pages 14: Investigation of the Influence of
           

    • Authors: Romy Peters, Dawon Jang, Daniel Sebastian Jens Wolz, Sungho Lee, Hubert Jäger, Mirko Richter, Chokri Cherif, Kiryl Vasiutovich, Marcus Richter, Xinliang Feng, Thomas Behnisch, Maik Gude
      First page: 14
      Abstract: For several decades, carbon fibers have been used for lightweight engineering in aircraft automotive and sports industries, mostly based on high-quality polyacrylonitrile (PAN). We investigated a novel PAN-based precursor fiber (PF) modified with a polycyclic aromatic hydrocarbon, namely hexabenzocoronene (HBC), which is expected to improve the thermal conversion process and to create a carbon fiber (CF) with enhanced mechanical properties. For this purpose, the novel PF and a spun-like homopolymeric PAN-based PF were thermally stabilized and carbonized in continuous lab-scale plants. The effect of the additive HBC on the conversion processes, fiber diameter and shape, density, and mechanical properties were investigated. The results showed that HBC seems to support stabilization reactions, and HBC/PAN-based PF show potentially higher stretchability of PF and stabilized fiber. The modified CF showed an improvement in Young’s modulus of about 25% at the same tensile strength compared to the unmodified PAN-based CF, resulting from enhanced crystalline orientation. The results showed a high potential of the HBC/PAN for energy-efficient production. In particular, the influence on tensile strength and modulus under optimized process conditions, as well as the possibility to use low quality PAN, need to be further investigated.
      Citation: Fibers
      PubDate: 2023-01-28
      DOI: 10.3390/fib11020014
      Issue No: Vol. 11, No. 2 (2023)
       
  • Fibers, Vol. 11, Pages 15: Reducing Plastic in Consumer Goods:
           Opportunities for Coarser Wool

    • Authors: Lisbeth Løvbak Berg, Ingun Grimstad Klepp, Anna Schytte Sigaard, Jan Broda, Monika Rom, Katarzyna Kobiela-Mendrek
      First page: 15
      Abstract: Production and use of plastic products have drastically increased during the past decades and their environmental impacts are increasingly spotlighted. At the same time, coarse wool, a by-product of meat and dairy production, goes largely unexploited in the EU. This paper asks why more coarse wool is not used in consumer goods, such as acoustic and sound-absorbing products, garden products, and sanitary products. This is answered through a SWOT analysis of results from a desktop study and interviews with producers of these products made from wool, as well as policy documents relating to wool, waste, textiles, and plastic. Findings show that on a product level, the many inherent properties of wool create opportunities for product development and sustainability improvements and that using the coarser wool represents an opportunity for replacing plastics in many applications as well as for innovation. This is, however, dependent on local infrastructure and small-scale enterprises, but as such, it creates opportunities for local value chains, value creation, and safeguarding of local heritage. The shift to small-scale and local resource utilization requires systemic change on several levels: Here the findings show that policy can incentivize material usage transitions, but that these tools are little employed currently.
      Citation: Fibers
      PubDate: 2023-01-28
      DOI: 10.3390/fib11020015
      Issue No: Vol. 11, No. 2 (2023)
       
  • Fibers, Vol. 11, Pages 16: Effect of Cross-Linkers on the Processing of
           Lignin/Polyamide Precursors for Carbon Fibres

    • Authors: Baljinder K. Kandola, Trishan A. M. Hewage, Muhammed Hajee, A. Richard Horrocks
      First page: 16
      Abstract: This work reports the use of cross-linkers in bio-based blends from hydroxypropyl-modified lignin (TcC) and a bio-based polyamide (PA1010) for possible use as carbon fibre precursors, which, while minimising their effects on melt processing into filaments, assist in cross-linking components during the subsequent thermal stabilisation stage. Cross-linkers included a highly sterically hindered aliphatic hydrocarbon (Perkadox 30, PdX), a mono-functional organic peroxide (Triganox 311, TnX), and two different hydroxyalkylamides (Primid® XL-552 (PmD 552) and Primid® QM-1260 (PmD 1260)). The characterisation of melt-compounded samples of TcC/PA1010 containing PdX and TnX indicated considerable cross-linking via FTIR, DSC, DMA and rheology measurements. While both Primids showed some evidence of cross-linking, it was less than with PdX and TnX. This was corroborated via melt spinning of the melt-compounded chips or pellet-coated TcC/PA1010, each with cross-linker via a continuous, sub-pilot scale, melt-spinning process, where both Primids showed better processability. With the latter technique, while filaments could be produced, they were very brittle. To overcome this, melt-spun TcC/PA1010 filaments were immersed in aqueous solutions of PmD 552 and PmD 1260 at 80 °C. The resultant filaments could be easily thermally stabilised and showed evidence of cross-linking, producing higher char residues than the control filaments in the TGA experiments.
      Citation: Fibers
      PubDate: 2023-01-29
      DOI: 10.3390/fib11020016
      Issue No: Vol. 11, No. 2 (2023)
       
  • Fibers, Vol. 11, Pages 17: Carbon Fiber-Reinforced Geopolymer Composites:
           A Review

    • Authors: Vojtěch Růžek, Ardak Mukhamedievna Dostayeva, Janusz Walter, Thomas Grab, Kinga Korniejenko
      First page: 17
      Abstract: The article summarizes the state of the art in carbon-reinforced geopolymers. It takes into consideration various types of matrices and types of carbon fibers (CFs). The article shows the growing importance of this composite in the investigation conducted in recent years. Today, it is one of the most promising modern research areas, taking into account the decrease in the prices of CFs and their appearance on the market waste-based CFs, as well as research on new methods of producing CFs from sustainable precursors. The research methods applied in the article are critical analyses of the literature. The results of the literature analysis are discussed in a comparative context, including production methods and the influence of CFs on geopolymer properties. The potential applications for carbon fiber-reinforced geopolymer composites are shown. Additionally, the current research challenges for geopolymer composites reinforced by CFs are presented.
      Citation: Fibers
      PubDate: 2023-02-01
      DOI: 10.3390/fib11020017
      Issue No: Vol. 11, No. 2 (2023)
       
  • Fibers, Vol. 11, Pages 18: Characterization and Simulation of Acoustic
           Properties of Sugarcane Bagasse-Based Composite Using Artificial Neural
           Network Model

    • Authors: Puyana-Romero, Chuquín, Chicaiza, Ciaburro
      First page: 18
      Abstract: Environmental sustainability and environmental protection represent essential challenges for the well-being of the community. The use of eco-sustainable materials in architecture is necessary for the transformation of urban centers into modern sustainable cities, to reduce air pollution and protect natural ecosystems, decrease greenhouse gas emissions and improve the energy efficiency of buildings. In this study, sugar cane processing waste was used as an alternative and ecological acoustic material, combining it with natural binders used in construction, such as plaster and clay. To make the composite, the fibers were separated from the bark, then the fibers were assembled with the binder in the frames, and finally the frame with the composite was subjected to a drying process. Specimens of various thicknesses were prepared and the sound absorption coefficient (SAC) at normal incidence was calculated. Subsequently, to compare the acoustic performances of the samples, a simulation model for the prediction of the SAC based on the artificial neural network (ANN) was created. The results suggest the adoption of the simulation model to review the acoustic properties of the material.
      Citation: Fibers
      PubDate: 2023-02-03
      DOI: 10.3390/fib11020018
      Issue No: Vol. 11, No. 2 (2023)
       
  • Fibers, Vol. 11, Pages 19: Thin-Layer Fibre-Reinforced Concrete Sandwich
           Walls: Numerical Evaluation

    • Authors: Ulvis Skadiņš, Kristens Kuļevskis, Andris Vulāns, Raitis Brencis
      First page: 19
      Abstract: In this study, structural thin-layer sandwich walls (SWs) made of steel-fibre-reinforced concrete (SFRC) without conventional reinforcements were investigated. Other researchers have shown that SWs with thin wythes can be used as load bearing structures in low-rise buildings, thereby reducing the amount of concrete by 2–5 times if compared to conventional reinforced-concrete SWs. In most studies, relatively warm climatic regions are the focus, and thin-layer SWs with shear connectors to obtain a certain level of composite action are investigated. In almost no studies has sound insulation been evaluated. In this study, a numerical investigation of structural, thermal and sound insulation performances was carried out. The load-bearing capacities of composite and non-composite SWs are compared. Regions with the lowest five-day mean air temperature of −20 ∘C were considered. The characteristics of the SW are compared to the requirements given in relevant European and Latvian standards. The minimum thermal insulation for family houses varies from 120 mm to 200 mm, depending on the material. To ensure sufficient sound insulation, the average thickness of the concrete wythes should be around 60 mm, preferably with a 15 mm difference between them. Structural analysis of the proposed wall panel was performed using non-linear finite element analysis software ATENA Science. The obtained load-bearing capacity exceeded the design loads of a single-story family house by around 100 times, regardless of the degree of composite action.
      Citation: Fibers
      PubDate: 2023-02-09
      DOI: 10.3390/fib11020019
      Issue No: Vol. 11, No. 2 (2023)
       
  • Fibers, Vol. 11, Pages 20: On the Design of Permanent Rock Support Using
           Fibre-Reinforced Shotcrete

    • Authors: Andreas Sjölander, Anders Ansell, Erik Nordström
      First page: 20
      Abstract: Fibre-reinforced shotcrete (sprayed concrete) is one of the major components in the support system for tunnels in hard rock. Several empirical design methodologies have been developed over the years due to the complexity and many uncertainties involved in rock support design. Therefore, this paper aims to highlight how the choice of design methodology and fibre type impacts the structural capacity of the lining and the emission of greenhouse gases (GHG). The paper starts with a review of different design methods. Then, an experimental campaign is presented in which the structural performance of shotcrete reinforced with various dosages of fibres made of steel, synthetic and basalt was compared. A case study is presented in which the permanent rock support is designed based on the presented design methods. Here, only the structural requirements were considered, and suitable dosages of fibres were selected based on the experimental results. The emission of GHG was calculated for all design options based on environmental product declarations for each fibre type. The result in this paper indicates that synthetic fibres have the greatest potential to lower the emissions of GHG in the design phase. Moreover, the choice of design method has a significant impact on the required dosage of fibres.
      Citation: Fibers
      PubDate: 2023-02-16
      DOI: 10.3390/fib11020020
      Issue No: Vol. 11, No. 2 (2023)
       
  • Fibers, Vol. 11, Pages 21: Nanofibres in Drug Delivery Applications

    • Authors: Samia Farhaj, Barbara R. Conway, Muhammad Usman Ghori
      First page: 21
      Abstract: Over the years, scientists have been continually striving to develop innovative solutions to design and fabricate medicines with improved therapeutic potential. Conventional dosage forms, such as tablets, capsules, and injections, are limited when exploited for advanced therapeutics, such as drug targeting. To cater to these limitations, nanofibres have emerged as novel nanomaterials to provide enhanced bioavailability, targeted drug release, extended drug release profile, minimum toxicity, and reduced dosage frequency, which has indisputably improved patient adherence and compliance. This review will concern understanding the potential of drug-loaded nanofibres in drug delivery while comprehending a detailed description of their different production methods. The literature has been thoroughly reviewed to appreciate their potential in developing nanofibrous-based pharmaceutical formulations. Overall, this review has highlighted the importance, versatility, and adaptability of nanofibres in developing medicines with varied drug release kinetics. Several problems must be resolved for their full commercial realisation, such as the drug loading, the initial burst effect, the residual organic solvent, the stability of active agents, and the combined usage of new or existing biocompatible polymers.
      Citation: Fibers
      PubDate: 2023-02-17
      DOI: 10.3390/fib11020021
      Issue No: Vol. 11, No. 2 (2023)
       
  • Fibers, Vol. 11, Pages 22: Compression of Few-Microjoule Femtosecond
           Pulses in a Hollow-Core Revolver Fiber

    • Authors: Leonid Losev, Vladimir Pazyuk, Alexey Gladyshev, Yury Yatsenko, Alexey Kosolapov, Igor Bufetov
      First page: 22
      Abstract: Gas-filled hollow-core fibers are a convenient tool for laser pulse compression down to a few-cycle duration. The development of compact, efficient and high quality compression schemes for laser pulses of relatively low μJ-level energies is of particular interest. In this work, temporal pulse compression based on nonlinear spectral broadening in a xenon-filled revolver fiber followed by a chirped mirror system is investigated. A 250 fs pulse at a central wavelength of 1.03 μm is compressed to 13.3 fs when the xenon pressure was tuned to provide zero group velocity dispersion near 1.03 μm. The energies of input and compressed pulses are 3.8 and 2.7 μJ, respectively. The compression quality factor of 1.8 is achieved.
      Citation: Fibers
      PubDate: 2023-02-20
      DOI: 10.3390/fib11020022
      Issue No: Vol. 11, No. 2 (2023)
       
  • Fibers, Vol. 11, Pages 5: Extraction and Physico-Chemical Characterization
           of Pineapple Crown Leaf Fibers (PCLF)

    • Authors: Vivek Johny, Ajith Kuriakose Kuriakose Mani, Sivasubramanian Palanisamy, Visakh Kunnathuparambil Rajan, Murugesan Palaniappan, Carlo Santulli
      First page: 5
      Abstract: Apart from the widely discussed pineapple leaf fibers, normally referred to as PALF, fibers from other parts of the plant also exist, particularly those in the fruit crown, which are known as pineapple crown leaf fibers (PCLF). In this work, PCLF were characterized using thermogravimetric analysis (TGA), Fourier transform IR spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The results indicated that the properties of PCLF do not greatly differ from those observed for PALF. In particular, a cellulose content of over 67% was observed, with approximately 76% crystallinity. The main degradation phenomena of the fibers took place between 230 and 380 °C, peaking at 324 °C, which is in line with observations in other fibers which have similar cellulose and crystalline contents. There was 13.4% residue at 680 °C. Bare mechanical retting of PCLF, although not allowing a full and thorough degumming, which would only be achieved through more aggressive chemical treatment, enabled aspect ratios of over 103 to be obtained. This indicates some potential for their application as short fibers in composites. In this respect, the considerable roughness of PCLF when compared to other leaf-extracted fibers, and in particular when compared to PALF, could suggest an ability to obtain a sufficiently sound fiber–matrix interface.
      Citation: Fibers
      PubDate: 2023-01-06
      DOI: 10.3390/fib11010005
      Issue No: Vol. 11, No. 1 (2023)
       
  • Fibers, Vol. 11, Pages 6: CFD Comparison of the Influence of Casting of
           Samples on the Fiber Orientation Distribution

    • Authors: Oksana Goidyk, Mark Heinštein, Heiko Herrmann
      First page: 6
      Abstract: The main goal of this research is to show that even a small deviation from the prescribed casting method EN 14651 causes a difference in fiber orientation distribution in sample beams. A further goal is to investigate the difference in the fiber orientation between bottom and side layers, which would carry the tensile load in the in-situ situation (bottom layer) compared to testing according to EN 14651 (side layer). Nowadays, the development of the proper numerical simulations that aim to visualize the casting process of the fresh concrete flow is a promising challenge in the construction industry. To be able to predict the orientation and spatial distribution of the short fibers using numerical tools may significantly simplify the investigations of the fibered composite materials. This paper compares simulations of different casting methods of the fiber concrete mixture with various flowabilities. The casting of the testing specimen was simulated in different ways: the filling of the formwork according to EN 14651, from the center only and from one edge of the formwork using computational fluid dynamics. The influence of different casting methods in combination with four specific sets of the rheological parameters on the final fiber orientation distribution is discussed. The presented outcomes of the simulations demonstrate that even a minor change in the casting procedure can significantly alter the final characteristics of the material.
      Citation: Fibers
      PubDate: 2023-01-10
      DOI: 10.3390/fib11010006
      Issue No: Vol. 11, No. 1 (2023)
       
  • Fibers, Vol. 11, Pages 7: Experimental Investigation of the Influence of
           Metallic Coatings on Yarn Pull-Out Behavior in Kevlar® Fabrics

    • Authors: Julie Roark, Frank D. Thomas, Subramani Sockalingam, Julia Kempf, Dan Christy, Derek Haas, Daniel J. O’Brien, Kris J. Senecal, Scott R. Crittenden
      First page: 7
      Abstract: This work reports yarn pull-out studies of commercially available Kevlar® KM2+ individual yarns coated with metallic layers (copper, aluminum, aluminum nitride and silver) via a directed vapor deposition process. The uncoated control and metal-coated Kevlar® yarns are hand-woven into fabric swatches for quasi-static pull-out experiments. To perform these experiments, a yarn pull-out fixture is custom-designed and fabricated to apply transverse pre-tension to the fabric. Three levels of transverse pre-tensions are studied at 100 N, 200 N, and 400 N. The results showed that both peak pull-out force and energy absorption during the pull-out process increase with increase in transverse pre-tension. All the metal-coated groups showed an approximately 200% increase in peak pull-out force and a 20% reduction in tenacity compared to uncoated control. Furthermore, all the metal-coated groups showed an increase in energy absorption, with aluminum-coated yarns showing the highest increase of 230% compared to control. These results suggest enhanced frictional interactions during yarn pull-out in metal-coated yarns compared to uncoated control as evidenced by the surface roughness profile of individual fibers and inter-yarn frictional calculations.
      Citation: Fibers
      PubDate: 2023-01-11
      DOI: 10.3390/fib11010007
      Issue No: Vol. 11, No. 1 (2023)
       
  • Fibers, Vol. 11, Pages 8: Electrochemical Oxidation of Pb II Using Carbon
           Electrodes Doped with Nanocellulose-FeOx

    • Authors: Araceli G. Gomez-Rojas, Luis Alejandro Macclesh del Pino-Perez, Carlos Fernando Castro-Guerrero, Claudia Esmeralda Ramos-Galvan, Ana Beatriz Morales-Cepeda
      First page: 8
      Abstract: With TEMPO oxidation, it was possible to incorporate iron nanostructures into a cellulose nanofiber matrix. FTIR spectra showed the functional groups present in the films. The combination of both iron and CNF confers to the films good electrochemical activity; the electrochemical characterization (CV) showed that they present stability in the reduction process at a potential of 0–1 V, with the materials with 5% and 10% being the most active. The Pb reduction process shows that the 5% film is the material with the highest oxidizing capacity.
      Citation: Fibers
      PubDate: 2023-01-12
      DOI: 10.3390/fib11010008
      Issue No: Vol. 11, No. 1 (2023)
       
  • Fibers, Vol. 11, Pages 9: Improving the Performance of Lightweight Crumb
           Rubber Mortar Using Synthetic, Natural, and Hybrid Fiber Reinforcements

    • Authors: S. M. Iqbal S. Zainal, Debbie Mattius, Zulhelmi Baba, Ahmad Nurfaidhi Rizalman, Farzad Hejazi
      First page: 9
      Abstract: The global market for tires is ever-growing, and partially replacing sand with crumb rubber (CR) as fine aggregates in concrete could reduce environmental pollution. However, the main barrier to the complete usage of recycled tire crumbs in construction is the deterioration effect of CR on the mechanical properties of cement-based composites. Therefore, this paper attempts to improve the fresh and hardened properties of crumb rubber mortar (CRM) by incorporating polypropylene-polyethylene synthetic fibers with coconut and kenaf natural fibers as reinforcements. A total of 18 mix designs were developed with varying fiber combinations and rubber crumb replacement. Subsequently, parametric studies with chemical admixture were conducted at 3, 7, and 28 days to improve the flowability and resulting mechanical properties of the fiber-reinforced CRM. According to the results, the single and hybrid fibers positively improved the mechanical properties of cement mortar at 5–15% CR replacement. It can be concluded that adding single and hybrid fibers enhanced the performance of cement mortar modified with tire crumb rubber aggregates by providing varying degrees of improvement.
      Citation: Fibers
      PubDate: 2023-01-12
      DOI: 10.3390/fib11010009
      Issue No: Vol. 11, No. 1 (2023)
       
  • Fibers, Vol. 11, Pages 10: Investigation of Fiber-Based Bag Filter Coated
           with Metal Oxides for Dust Adsorption

    • Authors: Marichelvam Mariappan Kadarkarainadar, Geetha Mariappan
      First page: 10
      Abstract: The production of cement increases every year, which leads to the emission of dust/gas/ particulate matter. The emission of unfiltered dust would create a significant environmental impact. Hence, it is the responsibility of industries to control the emission of dust. Air filters and electrostatic precipitators (ESP) play a significant role in controlling pollutants. Synthetic filter media which are dangerous to our environment are widely used in most industries. The disposal of synthetic filters is an arduous task as the biodegradability of synthetic materials is poor. Hence, it is essential to develop an eco-friendly air filter material. In this paper, a new type of bag filter was designed by using natural sisal fiber as filtering media. The biodegradability of sisal fiber is better than the synthetic polyester media and also sisal fiber is less expensive. The natural fibers were coated with zinc oxide and iron oxide nanoparticles to improve the dust adsorption rate. Various tests were conducted as per standards to validate the performance of the filler media. The results were impressive. Hence, the proposed sisal fiber-based filter media can be used in cement industries for dust adsorption to minimize the environmental impact.
      Citation: Fibers
      PubDate: 2023-01-13
      DOI: 10.3390/fib11010010
      Issue No: Vol. 11, No. 1 (2023)
       
  • Fibers, Vol. 11, Pages 11: Acknowledgment to the Reviewers of Fibers in
           2022

    • Authors: Fibers Editorial Office Fibers Editorial Office
      First page: 11
      Abstract: High-quality academic publishing is built on rigorous peer review [...]
      Citation: Fibers
      PubDate: 2023-01-16
      DOI: 10.3390/fib11010011
      Issue No: Vol. 11, No. 1 (2023)
       
  • Fibers, Vol. 11, Pages 1: Development of Thin Films from Thermomechanical
           Pulp Nanofibers of Radiata Pine (Pinus radiata D. Don) for Applications in
           Bio-Based Nanocomposites

    • Authors: Judith Vergara-Figueroa, Oswaldo Erazo, Héctor Pesenti, Paulina Valenzuela, Arturo Fernández-Pérez, William Gacitúa
      First page: 1
      Abstract: The main objective of this study was to develop cellulose nanofibers from the thermomechanical pulp (TMP) of Radiata Pine (Pinus radiata D. Don), and for this, a one-step micro-grinding process was used. The newly developed material was called thermomechanical pulp nanofibers (TMP-NF). In the first instance, a determination of the constituents of the TMP was carried out through a chemical characterization. Then, TMP-NFs were compared with cellulose nanofibers (CNF) by morphological analysis (Scanning Electron Microscopy, SEM, and Atomic Force Microscopy, AFM), X-Ray Diffraction (XRD) and Fourier-Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR). In addition, films were developed from TMP-NF and CNF using a vacuum filtration manufacturing method. For this study, 0.10, 0.25, 0.50, and 1.00% dry weight of CNF and TMP-NF were used as continuous matrices without organic solvents. The films were characterized by determining their morphological, physical, surface properties, and mechanical properties. The main results showed that morphological analysis by SEM and AFM for the fractionated sample indicated a fiber diameter distribution in the range of 990-17 nm and an average length of 5.8 µm. XRD analysis showed a crystallinity index of 90.8% in the CNF, while in the TMP-NF, it was 71.2%, which was foreseeable. FTIR-ATR analysis showed the functional groups of lignin and hemicellulose present in the TMP-NF sample. The films presented apparent porosity values of 33.63 for 1.00% solids content of CNF and 33.27% for 0.25% solids content of TMP-NF. The contact angle was 61.50° for 0.50% solids content of CNF and 84.60° for 1.00% solids content of TMP-NF. Regarding the mechanical properties, the modulus of elasticity was 74.65 MPa for CNF and 36.17 MPa for TMP-NF, and the tensile strength was 1.07 MPa for CNF and 0.69 MPa for TMP-NF. Although the mechanical properties turned out to be higher in the CNF films, the TMP-NF films showed improved surface characteristics as to surface hydrophobic and apparent porosity. In addition, the easy and rapid obtaining of TMP nanofibers makes it a promising material that can be used in biologically based nanocomposites.
      Citation: Fibers
      PubDate: 2022-12-20
      DOI: 10.3390/fib11010001
      Issue No: Vol. 11, No. 1 (2022)
       
  • Fibers, Vol. 11, Pages 2: Polymer-Modified Cellulose Nanofibrils
           Cross-Linked with Cobalt Iron Oxide Nanoparticles as a Gel Ink for 3D
           Printing Objects with Magnetic and Electrochemical Properties

    • Authors: Jakob Benedikt Mietner, Sebastian Willruth, Rajesh Komban, Christoph Gimmler, Bilal Nehmeh, Julien R. G. Navarro
      First page: 2
      Abstract: This paper presents a strategy to convert hydrophilic cellulose nanofibrils (CNF) into a highly cross-linked hydrophobic network with inorganic nanoparticles to develop a gel ink suitable for gel 3D printing. The CNF were chemically modified initially through a single-electron transfer-living radical polymerization (SET-LRP) of stearyl acrylate (SA) in the presence of the surface-modified cobalt iron oxide (CoFe2O4, CFO) nanoparticles. The modified CFO nanoparticles provide their multifunctional properties, such as magnetic and electrochemical, to the CNF hybrid network and, at the same time, act as cross-linking agents between the nanocellulose fibrils, while the grafted poly-stearyl acrylate (PSA) introduces a strong hydrophobicity in the network. A suitable gel ink form of this CNF–PSA–CFO material for gel 3D printing was achieved together with a certain solvent. Some test structure prints were directly obtained with the CNF–PSA–CFO gel and were used to evaluate the consolidation of such 3D objects through solvent exchange and freeze-drying while also keeping the magnetic and electrochemical properties of CFO in the CNF-based composite intact. The pristine CNF and CFO particles and the CNF–PSA–CFO were characterized by FTIR, SEM, XPS, TGA, VSM, and CV measurements.
      Citation: Fibers
      PubDate: 2022-12-21
      DOI: 10.3390/fib11010002
      Issue No: Vol. 11, No. 1 (2022)
       
  • Fibers, Vol. 11, Pages 3: Liquid Crystal Coated Yarns for
           Thermo-Responsive Textile Structures

    • Authors: Deña Mae Agra-Kooijman, Md Mostafa, Mourad Krifa, Linda Ohrn-McDaniel, John L. West, Antal Jákli
      First page: 3
      Abstract: We have developed a prototype of breathable thermochromic textile ideal for sensor applications, e.g., medical thermography. The textile was woven/knitted from polyester filaments pre-coated with thermochromic liquid crystal (TLC) ink, in lieu of coating the TLC ink on the woven/knitted textile. This process brings us closer to achieving breathable thermochromic textiles while enhancing the versatility of the textile. A combination of precoated yarns can be preselected according to the desired thermochromic properties of the textile. Swatches from both knitted and handwoven fabrics showed excellent reversible thermochromic property showing color from red to blue as the temperature is raised from 26 to 32 °C, consistent with the unincorporated TLC ink.
      Citation: Fibers
      PubDate: 2022-12-24
      DOI: 10.3390/fib11010003
      Issue No: Vol. 11, No. 1 (2022)
       
  • Fibers, Vol. 11, Pages 4: Experimental and Statistical Study of the Effect
           of Steel Fibers and Design Strength on the Variability in Repeated Impact
           Test Results

    • Authors: Ahmmad A. Abbass, Sallal R. Abid, Ali I. Abed, Sajjad H. Ali
      First page: 4
      Abstract: The ACI 544-2R repeated impact test is known as a low-cost and simple qualitative test to evaluate the impact strength of concrete. However, the test’s main deficiency is the high variability in its results. The effect of steel fibers and the compressive strength of concrete on the variability in repeated impact test results was investigated experimentally and statically in this study. Two batches from four mixtures were prepared and tested for this purpose. Hooked-end steel fibers were utilized in the fibrous mixtures. The mixtures NC, NC-SF0.5 and NC-SF1.0 were normal strength mixtures with 0, 0.5 and 1.0% of steel fibers, respectively, while HC was a plain high-strength mixture. The impact tests were conducted using an automatic testing machine following the setup of the ACI 544-2R repeated impact test. The impact numbers at cracking (N1) and at failure (N2) were recorded for both batches of the four mixtures. The results were also analyzed using the normal probability and Weibull distribution tests. The test results showed that the fibers increased the impact results at the cracking stage and significantly increased the failure impact resistance. Adding 0.5 and 1.0% of steel fibers increased the N1 by up to 66 and 111%, respectively, and increased the N2 by 114 and 374%, respectively. The test results also showed that duplicating the design compressive strength from 40 to 80 MPa increased the impact resistance by up to approximately 190%. The test results revealed no clear trend of an effect of steel fibers and compressive strength on the variability in the test results.
      Citation: Fibers
      PubDate: 2022-12-30
      DOI: 10.3390/fib11010004
      Issue No: Vol. 11, No. 1 (2022)
       
  • Fibers, Vol. 10, Pages 70: Assessment of Composite with Fibers as a
           Support for Antibacterial Nanomaterials: A Case Study of Bacterial
           Cellulose, Polylactide and Usual Textile

    • Authors: Ilya Lyagin, Olga Maslova, Nikolay Stepanov, Denis Presnov, Elena Efremenko
      First page: 70
      Abstract: To obtain composite fiber materials with antibacterial properties, the samples of bacterial cellulose (BC), polylactide (PLA) and usual fibers (FM) were modified by poly-ε-caprolactone or polyhydroxybutyrate and then functionalized by the enzyme-polyelectrolyte complex of quorum-quenching enzymes, such as hexahistidine-tagged organophosphorus hydrolase with poly(glutamic acid) or by suspension of tantalum nanoparticles (Ta NPs) in ethanol. The structures of the composite fibers were analyzed using scanning electron microscopy. It was shown that the introduction of additional natural polymers into the matrix of BC, PLA and FM resulted in decreasing of the structural porosity. Comparative studies of the antibacterial activity of the composite materials were carried out using Escherichia coli and Bacillus subtilis cells. The decrease of adenosine triphosphate concentration in cell samples loaded onto fiber materials was applied as a measurable characteristic of antibacterial effect typical for the new fiber materials. The profound improvement of antibacterial activity was determined in composite materials with polyhydroxybutyrate and Ta NPs.
      Citation: Fibers
      PubDate: 2022-08-24
      DOI: 10.3390/fib10090070
      Issue No: Vol. 10, No. 9 (2022)
       
  • Fibers, Vol. 10, Pages 71: Experimental Investigation of the Structural
           Performance of Existing and RC or CFRP Jacket-Strengthened Prestressed
           Cylindrical Concrete Pipes (PCCP)—Part A

    • Authors: George Manos, Konstantinos Katakalos, Vassilios Soulis, Lazaros Melidis, Vassilios Bardakis
      First page: 71
      Abstract: A popular water pipe system used in many countries is one formed by prestressed cylindrical concrete pipes (PCCPs) formed by identical precast moduli joined together in situ. This technology was and still is quite popular in many water supply systems internationally. This technology was mainly selected at the time due to its cost-based comparative advantage. However, over the years, numerous incidents of structural failures have been reported for this type of pipeline, causing, in some cases, serious disruption of the water supply. This study summarizes the results of an experimental investigation on ten (10) PCCP specimens taken from an existing water pipeline with the objective of investigating their bearing capacity under either three-edge bending or internal hydraulic pressure loads. Moreover, there is a need to check the capability of specific retrofitting/strengthening schemes to upgrade this bearing capacity and thus enhance the operational period. Provided that the prestressing wires are fully active according to design specifications, the original specimen performed satisfactorily for the set internal hydraulic pressure limit of 8.5 bar. Specimens retrofitted with either internal or external CFRP or RC jacketing performed satisfactorily for internal hydraulic pressure levels well above this 8.5 bar limit. A critical factor is, as expected, the loss of prestress.
      Citation: Fibers
      PubDate: 2022-08-24
      DOI: 10.3390/fib10090071
      Issue No: Vol. 10, No. 9 (2022)
       
  • Fibers, Vol. 10, Pages 72: Experimental Investigation of the Axial
           

    • Authors: Haris Ahmad Israr, King Jye Wong, Seyed Saeid Rahimian Koloor
      First page: 72
      Abstract: This study investigates the quasi-static axial crushing tests of eco-hybrid composites based on flax and E-glass fibres strengthened with polyester resin. Five different configurations of self-supporting webs were fabricated to investigate the crushing behaviours of this eco-hybrid composite with different stacking sequences based on intercalation and sandwich-like sequences. The effect of different open-section web profiles was also investigated. The results were plotted in load-displacement curves and the specific energy absorption (SEA), as well as the crushing force efficiency (CFE), were calculated to evaluate the crushing response of each configuration. The test results verified the crushing mechanisms related to the energy absorption depending on the stacking sequence as well as the frontal profile. In this study, all specimens with the intercalation stacking sequence have achieved higher SEA and CFE than specimens with a sandwich-like stacking sequence. In terms of the frontal profile, the sine wave hat shape had the highest CFE, up to 80% compared to other web profiles. Thus, it demonstrated the capability of a sine wave hat-shape eco-composite based on flax fibre to be applied as a crashworthy material.
      Citation: Fibers
      PubDate: 2022-08-26
      DOI: 10.3390/fib10090072
      Issue No: Vol. 10, No. 9 (2022)
       
  • Fibers, Vol. 10, Pages 73: Aloe vera Rind Valorization to Improve the
           Swelling Capacity of Commercial Acrylic Hydrogels

    • Authors: Marcelo A. Guancha-Chalapud, Liliana Serna-Cock, Diego F. Tirado
      First page: 73
      Abstract: Acrylic hydrogels have been used in agriculture to increase the availability of water in the soil; cause faster plant growth and increase plant survival to water stress; allow controlled release of fertilizers; and, therefore, increase crop yields. On the other hand, Aloe vera gel production generates a large amount of solid waste as cuticles, which is currently underutilized despite that it is a good source of cellulose nanofibers that could be used to improve the swelling capacity of commercial acrylic hydrogels. In this work, both morphology (SEM) and particle size (TEM) of the cellulose nanofibers obtained from A. vera cuticles by the acid hydrolysis method combined with ultrasound were analyzed; as well as the presence of functional groups (FITR) and thermal stability (TGA). Then, acrylic hydrogels were synthesized by the solution polymerization method, and nanofibers were added to these hydrogels at different concentrations (0% w w−1, 3% w w−1, 5% w w−1, and 10% w w−1). These concentrations had a nonlinear relationship with the swelling capacity, and the hydrogel reinforced at 3% cellulose nanofiber was chosen as the best formulation in this work, as this one improved the swelling capacity of hydrogels at equilibrium (476 g H2O g hydrogel−1) compared to the hydrogel without nanofiber (310 g H2O g hydrogel−1), while hydrogels with 10% nanofiber had a similar swelling capacity to the non-reinforced hydrogel (295 H2O g hydrogel−1). Therefore, cellulose-based superabsorbent hydrogels with potential application in agriculture were developed in this work.
      Citation: Fibers
      PubDate: 2022-08-30
      DOI: 10.3390/fib10090073
      Issue No: Vol. 10, No. 9 (2022)
       
  • Fibers, Vol. 10, Pages 74: Factors of Weave Estimation and the Effect of
           Weave Structure on Fabric Properties: A Review

    • Authors: Most. Setara Begum, Rimvydas Milašius
      First page: 74
      Abstract: This paper provides a review of recent studies on the weave factor along with the effect of weave parameters and particularly the weave structure on various properties of woven fabric. The weave structure can be considered as one of the prime parameters that contributes to the dominant physical and qualitative properties of the woven fabric. This study analyzed not only the parameters that significantly influence the properties of the woven fabric, but also the weave factors for the estimation of the weave that were proposed by earlier scientists. This review paper highlights the impact of weave structure on the physical and mechanical, thermo-physiological and comfort properties, and some special application properties of woven fabrics. This work seeks to serve as a future reference for related research.
      Citation: Fibers
      PubDate: 2022-08-30
      DOI: 10.3390/fib10090074
      Issue No: Vol. 10, No. 9 (2022)
       
  • Fibers, Vol. 10, Pages 75: Nanotubes: Carbon-Based Fibers and Bacterial
           Nano-Conduits Both Arousing a Global Interest and Conflicting Opinions

    • Authors: Silvana Alfei, Gian Carlo Schito
      First page: 75
      Abstract: Nanotubes (NTs) are mainly known as materials made from various substances, such as carbon, boron, or silicon, which share a nanosized tube-like structure. Among them, carbon-based NTs (CNTs) are the most researched group. CNTs, due to their nonpareil electrical, mechanical, and optical properties, can provide tremendous achievements in several fields of nanotechnology. Unfortunately, the high costs of production and the lack of unequivocally reliable toxicity data still prohibit their extensive application. In the last decade, a significant number of intriguing nanotubes-like structures were identified in bacteria (BNTs). The majority of experts define BNTs as membranous intercellular bridges that connect neighboring bacterial cell lying in proximity. Despite recent contrasting findings, most evidence suggested that bacteria exploit NTs to realize both antagonistic and cooperative intercellular exchanges of cytoplasmic molecules and nutrients. Among other consequences, it has been proposed that such molecular trade, including even plasmids, can facilitate the emergence of new non-heritable phenotypes and characteristics in multicellular bacterial communities, including resistance to antibiotics, with effects of paramount importance on global health. Here, we provide an enthralling comparison between CNTs, which are synthetically producible and ubiquitously exploitable for improving the quality of human life, and BNTs biosynthetically produced by prokaryotes, whose functions are not still fully clarified, but whose greater knowledge could be crucial to better understand the mechanisms of pathogenesis and combat the phenomenon of resistance.
      Citation: Fibers
      PubDate: 2022-09-01
      DOI: 10.3390/fib10090075
      Issue No: Vol. 10, No. 9 (2022)
       
  • Fibers, Vol. 10, Pages 76: The Quality of Blended Cotton and Denim Waste
           Fibres: The Effect of Blend Ratio and Waste Category

    • Authors: Mohammad Kanan, Bechir Wannassi, Ahmad S. Barham, Mohamed Ben Hassen, Ramiz Assaf
      First page: 76
      Abstract: Cotton is one of the most-used natural fibres in the world due to its relative comfort and strength compared with other natural fibres. However, the processing of cotton for manufacturing products consumes a lot of water, while harvesting cotton uses significant amounts of pesticides. One solution to this ecological problem is to recycle cotton waste. This study investigated the effect of blending virgin cotton with two categories of denim cotton waste—sourced during the winding and dyeing processes and used in various ratios—on the quality of blended denim cotton. The study was realised in collaboration with a large manufacturer of denim fabrics in Tunisia and a producer of preparation machines in Italy and aimed to use an adequate process to recycle cotton yarn waste and to obtain fibres with acceptable quality. The research aimed at providing a solution to the great demand for denim with the use of reclaimed fabric, which accompanies the increased need for denim with a fancy effect and the obligation of denim producers to follow environmental standards required by many brands The results show that it is possible to obtain a good quality of blend yarn using virgin cotton and cotton waste even when the waste content exceeds 50%. These results are significant for textile mills. Reprocessing fibres from denim colour-processing waste has a lot of advantages, including reductions in wastewater treatment and the consumption of energy, chemicals and water. In addition, the process eliminates the need for the dyeing and finishing processes of these coloured fibres.
      Citation: Fibers
      PubDate: 2022-09-02
      DOI: 10.3390/fib10090076
      Issue No: Vol. 10, No. 9 (2022)
       
  • Fibers, Vol. 10, Pages 77: Numerical Simulation of Convective Diffusion of
           Point Particles in a Laminar Flow Past a Row of Profiled Hollow Fibers

    • Authors: Vasily A. Kirsch
      First page: 77
      Abstract: The numerical modeling of transverse laminar flow past a new type of hollow-fiber membranes with external profiling has been performed. A model system of parallel fibers with symmetrical parallel protrusion obstacles or grooves is considered. The absorption of point particles (solute or gas molecules) from a laminar transverse flow of a viscous incompressible liquid (gas) is calculated for a row of fibers, and the dependences of the efficiency of retention of particles by fibers on the Peclet (Pe), Reynolds (Re), and Schmidt (Sc) numbers and on the distance between neighbor fibers in a row are determined. The flow velocity and concentration fields are calculated by numerical solution of the Navier–Stokes equations and the convective diffusion equation in a wide range of Peclet numbers Pe = 0.1 − 105 for Sc = 1, 10, 1000 and Re ≤ 100.
      Citation: Fibers
      PubDate: 2022-09-02
      DOI: 10.3390/fib10090077
      Issue No: Vol. 10, No. 9 (2022)
       
  • Fibers, Vol. 10, Pages 78: A Review on Drilling of Multilayer
           Fiber-Reinforced Polymer Composites and Aluminum Stacks: Optimization of
           

    • Authors: Gérald Franz, Pascal Vantomme, Muhammad Hafiz Hassan
      First page: 78
      Abstract: In recent years, the use of hybrid composite stacks, particularly CFRP/Al assemblies, and fiber metal laminates (FMLs) has progressively become a convincing alternative to fiber-reinforced polymers (FRPs) and conventional metal alloys to meet the requirements of structural weight reduction in the modern aerospace industry. These new structural materials, which combine greater mechanical properties with low specific mass, are commonly assembled by riveted and bolted joints. The drilling operation, which represents the essential hole-making process used in the aerospace industry, proves particularly challenging when it comes to achieving damage-free holes with tight tolerances for CFRP/Al stacks in one-shot operations under dry conditions due to the dissimilar mechanical and thermal behavior of each constituent. Rapid and severe tool wear, heat damage, oversized drilled holes and the formation of metal burrs are among the major issues induced by the drilling of multi-material stacks. This paper provides an in-depth review of recent advancements concerning the selection of optimized strategies for high-performance drilling of multi-material stacks by focusing on the significant conclusions of experimental investigations of the effects of drilling parameters and cutting tool characteristics on the drilling performance of aerospace assemblies with CFRP/Al stacks and FML materials. The feasibility of alternative drilling processes for improving the hole quality of hybrid composite stacks is also discussed.
      Citation: Fibers
      PubDate: 2022-09-09
      DOI: 10.3390/fib10090078
      Issue No: Vol. 10, No. 9 (2022)
       
  • Fibers, Vol. 10, Pages 79: Reducing Global Warming Potential Impact of
           Bio-Based Composites Based of LCA

    • Authors: Arta Seile, Ella Spurina, Maris Sinka
      First page: 79
      Abstract: The view towards a sustainable bioeconomy is increasing the interest of using renewable natural resources in the production of composites. Until now, the production of sustainable composites has been mainly examined from the point of view of material composition and structure, by replacing petroleum-based components with those that are obtained from renewable resources known as natural fiber composites (NFCs). The usefulness of newly acquired materials is mostly evaluated considering their performance and economic costs, whereas the aspect of environmental protection is underestimated. The impact of composites that are made from renewable resources is examined within the two parts of this study—the first part compares different nitrogen (N) fertilization scenarios for plant origin (hemp and flax) fibers. When compared, hemp crops show higher CO2 accumulation, (−1.57 kg CO2 eq) than flax (−1.27 kg CO2 eq). In addition, the environmental impact of both fiber types is compared to polyamide composites, one of the traditionally used materials in the automotive industry in the second part of this study. According to the conducted life cycle assessment, Flax/PLA emits 1.19 kg CO2 eq per 1 kg composite, Hemp/PLA 1.7 kg CO2 eq per 1 kg composite, and PA66/GF 9.14 kg CO2 eq per 1 kg composite. After the comparison, it was concluded that bio-based composites are able to ensure lower CO2 emissions, because CO2 is accumulated and stored in the fibers, however the traditionally used composites are able to provide a lower impact in other environmental categories.
      Citation: Fibers
      PubDate: 2022-09-14
      DOI: 10.3390/fib10090079
      Issue No: Vol. 10, No. 9 (2022)
       
  • Fibers, Vol. 10, Pages 80: The Role of Fiber-Type Reinforcement in the
           Torsional Behavior of Solid and Hollow Reinforced Concrete Beams

    • Authors: Mazin Diwan Abdullah, Fareed Hameed Majeed, Samoel Mahdi Saleh
      First page: 80
      Abstract: In order to improve the strength of concrete structures, the fiber reinforcement of concrete has become an essential factor. This study was conducted as an experimental program to gain a better understanding of how the variance of fiber shape and type affect the structural performance of solid and hollow reinforced concrete beams using four types of fiber (hooked-end, straight, corrugated steel fiber, and polyolefin fiber) under torsion. For this purpose, ten fiber-reinforced concrete beam specimens, five solid and five hollow, with square cross sections were fabricated using the adopted types of fiber. The role of fiber type in the improvement of the mechanical properties of hardened concrete was also investigated. The results revealed that the mechanical properties of the hardened concrete mix was enhanced by using the existing fiber in concrete, and the higher improvement was shown in the splitting tensile strength test and modulus of rapture in specimens with corrugated steel fiber. The torsional behavior of solid and hollow beams was improved significantly, and the capacity of torsional strength was especially improved for the beams strengthened with corrugated steel fiber. Straight and polyolefin fiber showed a slight improvement in the concrete mechanical properties and less enhancement in the torsional capacity of the tested beams. However, the tested beams reinforced by polyolefin fiber provide better ductility under torsion compared with the use of other types of fiber.
      Citation: Fibers
      PubDate: 2022-09-14
      DOI: 10.3390/fib10090080
      Issue No: Vol. 10, No. 9 (2022)
       
  • Fibers, Vol. 10, Pages 62: The Feasibility of Producing Particleboards
           

    • Authors: Washington Moreira Cavalcanti, Leandro Soares de Oliveira, Rômulo Maziero, Juan Carlos Campos Rubio
      First page: 62
      Abstract: The feasibility of using epoxidized waste cooking oils as a partial replacement for synthetic resins in the manufacture of lignocellulosic composites where the reinforcement is comprised of mechanically ground wood from civil construction waste wood (CCWW) was investigated. For this study, the wood-epoxy composite was prepared using the thermo-curing technique, and wood particle contents of 20 and 30% (m/m) were studied with a matrix comprised of 50% epoxidized vegetable oil and 50% petroleum-based epoxy resin. The specific mass of the composites was in the range of 1130 to 1380 kg/m3, with the lowest value for the highest content of wood particles. Fourier transform infrared spectroscopy was successfully used to monitor the epoxidation of the vegetable oils and the subsequent curing of the epoxy resins and particleboards. Thermal stability of the composite was dictated by its lignocellulosic content, and significant mass losses occurred at temperatures higher than 300 °C, regardless of the wood particles content. The introduction of CCWW particles into the polymeric matrices did not promote the desired effect of improving the mechanical properties in regard to those of the cured blend of epoxy resins. However, the produced particleboards still met the standards of the American National Standards for general purpose boards in regard to their physical and mechanical properties (e.g., density, tensile strength). Hence, the use of wood waste and waste cooking oil to produce particleboards was deemed justified within the framework of a cascading lifecycle-extended service for both wastes.
      Citation: Fibers
      PubDate: 2022-07-25
      DOI: 10.3390/fib10080062
      Issue No: Vol. 10, No. 8 (2022)
       
  • Fibers, Vol. 10, Pages 63: Characterisation of Elementary Kenaf Fibres
           Extracted Using HNO3 and H2O2/CH3COOH

    • Authors: Niphaphun Soatthiyanon, Alan Crosky
      First page: 63
      Abstract: In this study, elementary kenaf fibres were separated from fibre bundles using two different treatments. The first involved treating with nitric acid (HNO3) while the second used a mixture of hydrogen peroxide (H2O2) and acetic acid (CH3COOH). Both treatments were successful in isolating the elementary fibres but the H2O2/CH3COOH gave a better fibre yield and required a shorter treatment time. The fibres treated with HNO3 had an average length of 0.2 mm, an aspect ratio of 15 and a defect density of 21 defects per mm. In contrast, the H2O2/CH3COOH treated fibres had a length of 2.3 mm, an aspect ratio of 179 and a defect density of 14 defects per mm. Both treatments removed lignin, pectin, and waxes. They also increased cellulose crystallinity in the fibres, especially for HNO3 treatment. However, they resulted in some oxidation of cellulose. The H2O2/CH3COOH treatment gave a substantial improvement in the thermal stability of the fibres while a marked decrease was observed for the HNO3 treatment.
      Citation: Fibers
      PubDate: 2022-07-25
      DOI: 10.3390/fib10080063
      Issue No: Vol. 10, No. 8 (2022)
       
  • Fibers, Vol. 10, Pages 64: Statistical Modeling of Compressive Strength of
           Hybrid Fiber-Reinforced Concrete—HFRC

    • Authors: Uziel Cavalcanti de Medeiros Quinino, Roberto Christ, Bernardo Fonseca Tutikian, Luis Carlos Pinto da Silva
      First page: 64
      Abstract: The incorporation of reinforcements is a necessity to compensate for the deficiency that concrete presents with its fragile behavior and low deformation capacity. One of the solutions to improve tensile performance is the addition of fiber in random distributions throughout the volume. However, this strategy can compromise the compressive strength of concrete; consequently, the purpose of this study was to analyze the compressive strength of conventional concrete with hybrid fiber reinforcement. A behavioral equation of compressive strength as a function of the hybridization of three types of fibers (steel, polypropylene, and carbon) was determined. This equation accounted for the proportions, as well as the binary and tertiary combinations, of fibers. Results showed that the effective participation of metallic fibers and their combination with synthetic fibers contributed positively to the performance of fiber-reinforced concrete. The gain in axial compression strength reached values in the range of 10% to 19% depending on the content of total fibers and their combination, without problems in the production process.
      Citation: Fibers
      PubDate: 2022-07-27
      DOI: 10.3390/fib10080064
      Issue No: Vol. 10, No. 8 (2022)
       
  • Fibers, Vol. 10, Pages 65: The Significance of Multi-Size Carbon Fibers on
           the Mechanical and Fracture Characteristics of Fiber Reinforced Cement
           Composites

    • Authors: Mohammed Abdellatef, Daniel Heras Murcia, Joshua Hogancamp, Edward Matteo, John Stormont, Mahmoud M. Reda Taha
      First page: 65
      Abstract: One of the main challenges of using a high fiber volume content in a cement composite is the narrow margin of fiber volume content beyond which fibers can cause an adverse effect on the mechanical properties. In this paper, the significance of fiber size distribution and fiber volume content of different proportions of chopped and milled carbon microfibers are investigated. The mixes’ flowability showed improvement with altering the fiber size distribution despite having a high fiber content. Uniaxial compression cylinders and unnotched and notched beams were cast and then tested at 7 and 28 days of age. It was found that the compressive strength is significantly affected by fiber size distribution more than fiber volume content. On the other hand, the modulus of rupture and fracture toughness are proportional to the fiber volume content with little effect of fiber size distribution. Finally, neither high fiber volume content nor altered fiber size distribution significantly affected the elastic modulus of the fiber cement composites.
      Citation: Fibers
      PubDate: 2022-07-28
      DOI: 10.3390/fib10080065
      Issue No: Vol. 10, No. 8 (2022)
       
  • Fibers, Vol. 10, Pages 66: The Impact of Atmospheric Plasma/UV Laser
           Treatment on the Chemical and Physical Properties of Cotton and Polyester
           Fabrics

    • Authors: Maram Ayesh, A. Richard Horrocks, Baljinder K. Kandola
      First page: 66
      Abstract: Atmospheric plasma treatment can modify fabric surfaces without affecting their bulk properties. One recently developed, novel variant combines both plasma and UV laser energy sources as a means of energising fibre surfaces. Using this system, the two most commonly used fibres, cotton and polyester, have been studied to assess how respective fabric surfaces were influenced by plasma power dosage, atmosphere composition and the effects of the presence or absence of UV laser (308 nm XeCl) energy. Plasma/UV exposures caused physical and chemical changes on both fabric surfaces, which were characterised using a number of techniques including scanning electron microscopy (SEM), radical scavenging (using 2,2-diphenyl-1-picrylhydrazyl (DPPH)), thermal analysis (TGA/DTG, DSC and DMA), electron paramagnetic resonance (EPR) and X-ray photoelectron spectroscopy (XPS). Other properties studied included wettability and dye uptake. Intermediate radical formation, influenced by plasma power and presence or absence of UV, was key in determining surface changes, especially in the presence of low concentrations of oxygen or carbon dioxide (20%) mixed with either nitrogen or argon. Increased dyeability with methylene blue indicated the formation of carboxyl groups in both exposed cotton and polyester fabrics. In the case of polyester, thermal analysis suggested increased cross-linking had occurred under all conditions.
      Citation: Fibers
      PubDate: 2022-07-28
      DOI: 10.3390/fib10080066
      Issue No: Vol. 10, No. 8 (2022)
       
  • Fibers, Vol. 10, Pages 67: Evaluation of the Maximum Strain for Different
           Steel-FRCM Systems in RC Beams Strengthened in Flexure

    • Authors: Francesco Bencardino, Mattia Nisticò
      First page: 67
      Abstract: The strengthening of existing reinforced concrete (RC) structures by means of steel-fabric reinforced cementitious matrix (Steel-FRCM) systems has been universally recognized in the academic literature as an effective method. Several types of steel fibres can be found in the marketplace, and they are classified according to mass per unit area and tensile strength. In the flexural strengthening design of RC beams, a fundamental parameter is the effective tensile strain level in the Steel-FRCM system attained at failure. Some authors and guidelines suggest evaluating this strain value using the results of bond tests. As is well highlighted in many works, the debonding strain in Steel-FRCM composites applied on concrete beams is usually higher than that from single-lap shear tests. At this point, it can be easily obtained by applying an appropriate amplification coefficient. This study experimentally investigates the difference in the debonding strain between Steel-FRCM composites bonded to concrete blocks in single-lap shear tests (end strain) versus the debonding strain in concrete beams (intermediate strain). The results were used to critically discuss the variability of the amplification coefficient, significantly affected by the mechanical and geometrical properties of the steel fibres. Moreover, a simple predictive formula to evaluate the intermediate strain debonding was used, and the results were compared with the experimental evidence. Finally, a large database of direct shear and flexural tests was used to confirm the experimental and theoretical data obtained herein.
      Citation: Fibers
      PubDate: 2022-08-04
      DOI: 10.3390/fib10080067
      Issue No: Vol. 10, No. 8 (2022)
       
  • Fibers, Vol. 10, Pages 68: Fibres as Replacement of Horizontal Ties in
           Compressed Reinforced Concrete Elements: Experimental Study

    • Authors: Ulvis Skadiņš
      First page: 68
      Abstract: Steel fibres provide ductility to concrete structures. This, in turn, gives possibility to replace or reduce conventional reinforcement in structural elements. In this study, the focus is on structural walls and the fibres as potential replacements for horizontal reinforcement in areas where vertical rebars are needed. An experimental study was conducted, in which prismatic specimens with longitudinal rebars were subjected to centric loading. Ten samples with 12 specimens in each were tested. The parameters considered were: fibre content, concrete cover for the longitudinal bars, and presence of stirrups. Self-compacting concrete with 30 and 60 kg/m3 steel fibres was used. Relative and normalised values of the test results were calculated; correlation and analysis of variance was used to estimate the effect of fibres. The results show that the fibres eliminated brittle collapse and spalling of concrete at failure. A strong negative correlation (−0.72 to −0.92) between amount of fibres and load-bearing capacity was found. On average, the reduction of the capacity was 8% to 16% if compared to the specimens with no fibres. However, a positive effect of the fibres on the ductility was observed. Specimens with 30 kg/m3 fibres showed the same post-peak behaviour as specimens with minimum horizontal reinforcement required by Eurocode 2. The study suggests that combination of steel fibres and conventional rebars can lead to less qualitative compactness of the self-compacting concrete, which in turn may reduce load-bearing capacity and stiffness of the structure. Special attention on concrete cover and distance between rebars should be paid if self-compacting concrete structures with steel fibres are designed.
      Citation: Fibers
      PubDate: 2022-08-10
      DOI: 10.3390/fib10080068
      Issue No: Vol. 10, No. 8 (2022)
       
  • Fibers, Vol. 10, Pages 69: Indentation of Anisotropic Tissue Using a
           Three-Dimensional Mechanical Bidomain Model

    • Authors: Dilmini Wijesinghe, Bradley J. Roth
      First page: 69
      Abstract: Computation-based mathematical models of tissue indentation are capable of predicting the distribution of forces and mechanical properties of soft tissues. This paper presents a three-dimensional mathematical model of anisotropic tissue indentation developed using the mechanical bidomain model. The mechanical bidomain model hypothesizes that the relative displacement between intra- and extracellular spaces triggers a force on the mechanosensitive proteins in the membrane: integrins. Some soft tissues, such as cardiac muscle, are anisotropic, a property which arises from the fibrous structure of the tissue. The degree of anisotropy in intra- and extracellular spaces can be different. Tissue indentation for different anisotropy ratios that indicate isotropy, equal anisotropy and unequal anisotropy, were tested using the model. Results of the tissue indentation analysis compared the spatial distribution of the magnitude of bidomain displacement for different anisotropy conditions between monodomain and bidomain models. The proposed mathematical model predicted unexpected spatial patterns of cardiac mechanotransduction for unequal anisotropy ratios of mechanical modulus.
      Citation: Fibers
      PubDate: 2022-08-19
      DOI: 10.3390/fib10080069
      Issue No: Vol. 10, No. 8 (2022)
       
  • Fibers, Vol. 10, Pages 58: Simple Synthesis of Fe3O4@-Activated Carbon
           from Wastepaper for Dispersive Magnetic Solid-Phase Extraction of
           Non-Steroidal Anti-Inflammatory Drugs and Their UHPLC–PDA
           Determination in Human Plasma

    • Authors: Vincenzo Ferrone, Pantaleone Bruni, Valentino Canale, Leonardo Sbrascini, Francesco Nobili, Giuseppe Carlucci, Stefania Ferrari
      First page: 58
      Abstract: In the present society, the recycling and reuse of valuable substances are of utmost importance for economic and environmental purposes. At the same time, there is a pressing need to develop new methods to protect the ecosystem from many human activities, including those that have contributed to an ever-increasing presence of pharmaceutical pollutants. In this study, a straightforward approach that applies a magnetic carbon composite for the effective removal of NSAIDs from biological fluids is reported. The composite was produced by recycling wasted handkerchiefs, to provide cellulose to the reactive system and then transformed into carbon via calcination at high temperature. The morphological and structural features of the prepared “Fe3O4@-activated carbon” samples were investigated via thermal analysis, X-ray diffraction, Raman spectroscopy, and scanning electron microscopy. Magnetic solid-state extraction was carried out to reveal the adsorption capabilities of the magnetic carbon composite and then combined with UHPLC–PDA for the determination and quantification of five NSAIDs (furprofen, indoprofen, ketoprofen, flurbiprofen, and indomethacin). The method developed herein proved to be fast and accurate. The adsorbent could be reused for up to 10 cycles, without any decrease in performance; thus, it contributes to an intelligent and sustainable economic strategy projected toward minimal waste generation.
      Citation: Fibers
      PubDate: 2022-07-01
      DOI: 10.3390/fib10070058
      Issue No: Vol. 10, No. 7 (2022)
       
  • Fibers, Vol. 10, Pages 59: Interlaminar Shear Properties of Bamboo
           Composite for Structural Applications

    • Authors: Ali Rajabipour, Alireza Javadian, Milad Bazli, Mark Masia
      First page: 59
      Abstract: Interlaminar shear strength in bamboo composite (BC) is mainly provided by epoxy resin as the matrix in BC. This may greatly change due to humidity. This study aims at evaluating the shear strength of BC by testing and developing probabilistic relationships. The interlaminar shear strength of bamboo composite (BC) in different moisture conditions was tested according to ASTM D2344. The results show that the maximum shear stress does not generally occur at the centroid of samples, which could be associated with imperfections in BC layers. An extreme value theory-based model is suggested to evaluate the probability of shear failure in BC samples. The shear capacity decreased from 20.4 MPa to 14 MPa as the humidity increased from 60% to 90%. A summary of findings is as follows: It was found that under transient moisture conditions, local failure is likely to happen before the first significant crack occurs. Local failure is suggested to be considered in the design for serviceability. Stress drop caused by the local failure could exceed 10% of total shear strength and, therefore, should be regarded as a serviceability design. The probabilistic model developed in this study could be used for developing structural design safety factors.
      Citation: Fibers
      PubDate: 2022-07-12
      DOI: 10.3390/fib10070059
      Issue No: Vol. 10, No. 7 (2022)
       
  • Fibers, Vol. 10, Pages 60: Tribological Analysis of Jute/Coir Polyester
           Composites Filled with Eggshell Powder (ESP) or Nanoclay (NC) Using Grey
           Rational Method

    • Authors: Ganesan Karuppiah, Kailasanathan Chidambara Kuttalam, Nadir Ayrilmis, Rajini Nagarajan, M. P. Indira Devi, Sivasubramanian Palanisamy, Carlo Santulli
      First page: 60
      Abstract: The wear performance of jute/coir unsaturated polyester composites, filled with eggshell powder (ESP) and nanoclay (NC), were examined, concentrating on two measured parameters, coefficient of friction (COF) and wear rate (WR). To assess the possibilities of this material, a Taguchi study, based on grey relational analysis (GRA), was carried out, based on three testing parameters of the wear performance, load (10, 20, and 30 N), speed (100, 150, and 200 rpm), and sliding distance (30, 40, and 50 m). The material showed promising characteristics especially at high load, low speed, and high sliding distance. When comparing the respective influence of the three different parameters, the speed proved to be the most critical, this suggested the possible application of the biocomposite only for very low values of it. On the other hand, it was also elucidated that the presence and interfacial adhesion of the two fillers considerably hindered the formation of ploughing during wear test, despite the fact that degradation might be continuous and critical as far as loading progresses.
      Citation: Fibers
      PubDate: 2022-07-12
      DOI: 10.3390/fib10070060
      Issue No: Vol. 10, No. 7 (2022)
       
  • Fibers, Vol. 10, Pages 61: Isolation and Properties of Cellulose
           Nanocrystals Fabricated by Ammonium Persulfate Oxidation from Sansevieria
           trifasciata Fibers

    • Authors: Nafiis Lazuardi Indirasetyo, Kusmono
      First page: 61
      Abstract: Cellulose nanocrystals (CNCs) were successfully prepared from Sansevieria trifasciata fibers (STFs) via ammonium persulfate (APS) oxidation in this study. The influences of the APS concentration (1.1, 1.5, and 1.9 M) and oxidation temperature (60, 70, and 80 °C) on the characteristics of CNCs were studied. The resulting CNCs were characterized using Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The TEM observations revealed that the rod-like CNCs possessed average length and diameter ranges of 96 to 211 nm and 5 to 13 nm, respectively, which led to an aspect ratio range of 16–19. The optimum conditions for maximum crystallinity were achieved at an oxidation temperature of 70 °C, a reaction time of 16 h, and an APS concentration of 1.5 M. All CNCs exhibited lower thermal stability compared to the STFs. The CNCs could be produced from the STFs through the APS oxidation process and showed potential as nanocomposite reinforcement materials.
      Citation: Fibers
      PubDate: 2022-07-13
      DOI: 10.3390/fib10070061
      Issue No: Vol. 10, No. 7 (2022)
       
  • Fibers, Vol. 10, Pages 102: Development of 100% Linseed Flax Yarns with
           Improved Mechanical Properties and Durability for Geotextiles Applications
           

    • Authors: Saif Ullah Khan, Mahadev Bar, Philippe Evon, Laurent Labonne, Pierre Ouagne
      First page: 102
      Abstract: Due to the ever-growing demand for bast fibres for technical and garment textiles, complementary sources to textile flax, whose cultivation in western Europe cannot really be extended, need to be proposed. In this study, the interest in harvesting and processing linseed flax straw is studied for geotextile applications. The main critical stages of fibre-to-yarn production for geotextiles were investigated. Different dew retting levels as well as different all-fibre extraction processes were investigated to achieve this objective. It was demonstrated that the fibres extracted from linseed flax stems subjected to 12 weeks of dew retting using breaking rollers, thresher and a breaking card exhibited the most suitable morphological and mechanical properties. The optimal fibres were converted into 100% linseed flax yarns using a flyer spinning machine, and the mechanical properties as well as the biodegradability of the linseed yarns were evaluated to understand their potential as geotextiles. These linseed flax yarns were further coated with linseed oil or chitosan to enhance their durability. It was observed that the linseed oil coating better preserved the yarn’s integrity and mechanical properties over time, and it permitted doubling their service life potential.
      Citation: Fibers
      PubDate: 2022-11-23
      DOI: 10.3390/fib10120102
      Issue No: Vol. 10, No. 12 (2022)
       
  • Fibers, Vol. 10, Pages 103: Influence of Stirrup Spacing on the
           Strengthening and Rehabilitating of RC T-beams Using Near-Surface Mounted
           Carbon-Fiber-Reinforced Polymer Strips

    • Authors: Ma’en Abdel-Jaber, Mu’tasim Abdel-Jaber, Hasan Katkhuda, Nasim Shatarat, Alaa Sulaiman, Rola El-Nimri
      First page: 103
      Abstract: This paper aims to investigate the effect of using different configurations of near-surface mounted carbon-fiber-reinforced polymer (NSM-CFRP) strips on the shear strength of strengthened and rehabilitated reinforced concrete (RC) T-beams with different internal shear stirrup spacing. The internal shear stirrup spacing was 50 and 150 mm. The NSM-CFRP strips were at an inclination of 45° and spaced at 75 and 150 mm. A total of eight beams were tested in this study: two beams without NSM-CFRP as control beams for the purpose of comparison; three beams were strengthened by NSM-CFRP; and three beams were rehabilitated by NSM-CFRP. The experimental shear capacities were compared with the theoretical values predicted by the ACI 440.2R-17. The results indicated that the use of NSM-CFRP strips enhanced the shear capacity for all beams compared to their corresponding control beams. The enhancements in the shear capacity increased with the decrease in the spacing of the internal shear stirrups and NSM-CFRP strips. The ACI 440.2R-17 was conservative in predicting the theoretical shear capacities.
      Citation: Fibers
      PubDate: 2022-11-28
      DOI: 10.3390/fib10120103
      Issue No: Vol. 10, No. 12 (2022)
       
  • Fibers, Vol. 10, Pages 104: Evaluation of the Tensile Characteristics and
           Bond Behaviour of Steel Fibre-Reinforced Concrete: An Overview

    • Authors: Mohammed A. Mujalli, Samir Dirar, Emad Mushtaha, Aseel Hussien, Aref Maksoud
      First page: 104
      Abstract: Conventional concrete is a common building material that is often ridden with cracks due to its low tensile strength. Moreover, it has relatively low shear strength and, unless reinforced, undergoes brittle failure under tension and shear. Thus, concrete must be adequately reinforced to prevent brittle tensile and shear failures. Steel fibres are commonly used for this purpose, which can partially or fully replace traditional steel reinforcement. The strength properties and bond characteristics between reinforcing steel fibres and the concrete matrix are crucial in ensuring the effective performance of the composite material. In particular, the quality of the bond has a significant impact on crack development, crack spacing, and crack width, among other parameters. Hence, the proper application of steel fibre-reinforced concrete (SFRC) requires a thorough understanding of the factors influencing its bond behaviour and strength properties. This paper offers a comprehensive review of the main factors controlling the bond behaviour between concrete and steel fibres in SFRC. In particular, we focus on the effects of the physical and mechanical properties of steel fibres (e.g., geometry, inclination angle, embedded length, diameter, and tensile strength) on the bond behaviour. We find that the addition of up to 2% of steel fibres into concrete mixtures can significantly enhance the compressive strength, tensile strength, and flexural strength of concrete components (by about 20%, 143%, and 167%, respectively). Furthermore, a significant enhancement in the pull-out performance of the concrete is observed with the addition of steel fibres at various dosages and geometries.
      Citation: Fibers
      PubDate: 2022-12-02
      DOI: 10.3390/fib10120104
      Issue No: Vol. 10, No. 12 (2022)
       
  • Fibers, Vol. 10, Pages 105: Damage Tolerance of a Stiffened Composite
           Panel with an Access Cutout under Fatigue Loading and Validation Using FEM
           Analysis and Digital Image Correlation

    • Authors: Pavan Hiremath, Sathyamangalam Ramanarayanan Viswamurthy, Manjunath Shettar, Nithesh Naik, Suhas Kowshik
      First page: 105
      Abstract: Aircraft structures must be capable of performing their function throughout their design life while meeting safety objectives. Such structures may contain defects and/or damages that can occur for several reasons. Therefore, aircraft structures are inspected regularly and repaired if necessary. The concept of combining an inspection plan with knowledge of damage threats, damage growth rates, and residual strength is referred to as “damage-tolerant design” in the field of aircraft design. In the present study, we fabricated a composite panel with a cutout (which is generally found in the bottom skin of the wing) using a resin infusion process and studied the damage tolerance of a co-cured skin-stringer composite panel. The composite panel was subjected to low-velocity impact damage, and the extent of damage was studied based on non-destructive inspection techniques such as ultrasonic inspection. Fixtures were designed and fabricated to load the composite panel under static and fatigue loads. Finally, the panel was tested under tensile and fatigue loads (mini TWIST). Deformations and strains obtained from FE simulations were compared and verified against test data. Results show that the impact damages considered in this study did not alter the load path in the composite panel. Damage did not occur under the application of one block (10% life) of spectrum fatigue loads. The damage tolerance of the stiffened skin composite panel was demonstrated through test and analysis.
      Citation: Fibers
      PubDate: 2022-12-08
      DOI: 10.3390/fib10120105
      Issue No: Vol. 10, No. 12 (2022)
       
  • Fibers, Vol. 10, Pages 106: Design and Evaluation of a Learning-Based
           Vascular Interventional Surgery Robot

    • Authors: Xingyu Chen, Yinan Chen, Wenke Duan, Toluwanimi Oluwadara Akinyemi, Guanlin Yi, Jie Jiang, Wenjing Du, Olatunji Mumini Omisore
      First page: 106
      Abstract: Interventional therapy is one of the most effective methods for diagnosing and treating vascular-related diseases at present. It relies on achieving precise and safe navigation of intravascular tools within a patient’s vasculature. Vascular Interventional Surgical Robots (VISR) can reduce surgeons’ exposure to operational hazards including radiation. However, the absence of apt position control and force feedback remains a challenge. This study presents an isomorphic master–slave VISR for precise navigation of endovascular tools viz. catheters and guidewires. The master console aids operators in issuing manipulation commands and logs feedback from the force, rotation, and translation data. The slave manipulator uses the commands received from the master platform for actual tool navigation. However, precise master–slave position control and force feedback are precursors for optimal patient outcomes. This study utilized a fuzzy-PID controller for precise tool navigation and a neural network model for resistance force modulation with 50 mN precision. Furthermore, we evaluated the performance of using the learning-based models within our VISR and compared it with the performances from conventional methods. Results show that the models enhanced the proposed robotic system with better navigation precision, faster response speed, and improved force measurement capabilities.
      Citation: Fibers
      PubDate: 2022-12-13
      DOI: 10.3390/fib10120106
      Issue No: Vol. 10, No. 12 (2022)
       
  • Fibers, Vol. 10, Pages 107: Performance of Steel Bar Lap Splices at the
           Base of Seismic Resistant Reinforced Concrete Columns Retrofitted with
           FRPs—3D Finite Element Analysis

    • Authors: Evgenia Anagnostou, Theodoros Rousakis
      First page: 107
      Abstract: This paper examines analytically the design criteria for the composite retrofit of reinforced concrete (RC) columns with a short lap splice length of steel rebars inside the critical region. The advanced potential of pseudo-dynamic three-dimensional (3D) finite element (FE) modelling is utilized to investigate critical design parameters for the required carbon fiber-reinforced polymer (FRP) jacketing of RC columns with a rectangular cross-section based on the experimental lateral force-to-drift envelope behavior of characteristic cases from the international literature. The satisfactory analytical reproduction of the experimental results allows for the systematic numerical investigation of the developed stress along the lap splice length. The maximum lateral force and the horizontal displacement ductility of the column, as well as the maximum developed tensile axial force on the longitudinal bars, their variation along the lap, the bar yielding, and the plastic hinge length variation, are considered to determine the seismic behavior of the columns. For the first time, cases of smooth bar slip together with delayed bar yielding or without bar yielding are identified that may be recorded through a “ductile” P-d seismic response. Such pseudo-ductile response cases are revisited through suitably revised redesign criteria for adequate FRP jacketing.
      Citation: Fibers
      PubDate: 2022-12-14
      DOI: 10.3390/fib10120107
      Issue No: Vol. 10, No. 12 (2022)
       
  • Fibers, Vol. 10, Pages 108: Carbon Fibers from Wet-Spun Cellulose-Lignin
           Precursors Using the Cold Alkali Process

    • Authors: Andreas Bengtsson, Alice Landmér, Lars Norberg, Shun Yu, Monica Ek, Elisabet Brännvall, Maria Sedin
      First page: 108
      Abstract: In recent years, there has been extensive research into the development of cheaper and more sustainable carbon fiber (CF) precursors, and air-gap-spun cellulose-lignin precursors have gained considerable attention where ionic liquids have been used for the co-dissolution of cellulose and lignin. However, ionic liquids are expensive and difficult to recycle. In the present work, an aqueous solvent system, cold alkali, was used to prepare cellulose-lignin CF precursors by wet spinning solutions containing co-dissolved dissolving-grade kraft pulp and softwood kraft lignin. Precursors containing up to 30 wt% lignin were successfully spun using two different coagulation bath compositions, where one of them introduced a flame retardant into the precursor to increase the CF conversion yield. The precursors were converted to CFs via batchwise and continuous conversion. The precursor and conversion conditions had a significant effect on the conversion yield (12–44 wt%), the Young’s modulus (33–77 GPa), and the tensile strength (0.48–1.17 GPa), while the precursor morphology was preserved. Structural characterization of the precursors and CFs showed that a more oriented and crystalline precursor gave a more ordered CF structure with higher tensile properties. The continuous conversion trials highlighted the importance of tension control to increase the mechanical properties of the CFs.
      Citation: Fibers
      PubDate: 2022-12-15
      DOI: 10.3390/fib10120108
      Issue No: Vol. 10, No. 12 (2022)
       
  • Fibers, Vol. 10, Pages 109: Differentiation in the SiC Filler Size Effect
           in the Mechanical and Tribological Properties of Friction-Spot-Welded
           AA5083-H116 Alloy

    • Authors: S. Suresh, Elango Natarajan, Gérald Franz, S. Rajesh
      First page: 109
      Abstract: Ceramic reinforced friction stir spot-welding (FSSW) is one of the unique welding techniques used to fabricate spot joints. This study is intended to investigate the effect of reinforcement additive particle size in achieving higher weld strengths. AA5083-H116 aluminum alloy plates were welded with nano- and micro-sized silicon carbide (SiC) particles. Investigations of the weld joints prepared using a tool rotational speed of 1300 rpm, tool plunge rate of 25 mm/min, and dwell time of 10 s revealed that the lap shear tensile strength and hardness of the nano-SiC particles added to aluminum joints were higher than those of the micro-SiC particles added to joints. In particular, the nano-SiC particles provided 29.6% higher strength and 23.3% higher hardness than the unfilled FSSW. The uniformly dispersed fine SiC particles in the processed zone provided more nucleation sites for the re-precipitation of new grains and the precipitates in the aluminum matrix. The X-ray diffraction results confirmed that there was no evidence of a new phase (intermetallic compounds). Reinforcement of SiC particles significantly enhanced the wear characteristics, as well (26.3%). Field emission scanning electron microscopy (FESEM) evidenced the uniform distribution of SiC particles in the weld nugget zone. In addition, the fractography of the samples is presented and discussed.
      Citation: Fibers
      PubDate: 2022-12-15
      DOI: 10.3390/fib10120109
      Issue No: Vol. 10, No. 12 (2022)
       
  • Fibers, Vol. 10, Pages 93: Numerical Study of the Performance of Existing
           Prestressed Cylindrical Concrete Pipes Strengthened with Reinforced
           Concrete or Carbon-Reinforced Fiber Polymer Jackets—Part B

    • Authors: Konstantinos Katakalos, Lazaros Melidis, George Manos, Vassilios Soulis
      First page: 93
      Abstract: A popular water pipe system, used in many countries, is one formed by prestressed cylindrical concrete pipes (PCCP). This study used the results of an experimental investigation on ten (10) PCCP samples taken from an existing water pipeline. The objective was to investigate their bearing capacity under three-edge bending or internal hydraulic pressure loads to check the capability of specific retrofitting/strengthening schemes to upgrade this bearing capacity and thus enhance the operational period (Part A). In this part B study, the measured response of the PCCP pipes was made to validate a numerical approach aimed at numerically simulating the behavior of the original and retrofitted PCCP pipes under hydraulic internal pressure. From the obtained numerical results, it was seen that the assumed nonlinear mechanisms for the concrete volume and steel membrane were verified by comparing numerical predictions with measurements in terms of strain response of the steel membrane, damage patterns of the concrete volume, and the overall internal pressure versus radial expansion response. The numerical predictions of the bearing capacity contribution of the fully active prestress as well as the three specific jacketing schemes, including carbon fiber reinforced polymer (CFRP) or reinforced concrete (RC) jackets, were also verified from comparisons with the corresponding measured response.
      Citation: Fibers
      PubDate: 2022-10-28
      DOI: 10.3390/fib10110093
      Issue No: Vol. 10, No. 11 (2022)
       
  • Fibers, Vol. 10, Pages 94: Invasive Alien Plant Species for Use in Paper
           and Packaging Materials

    • Authors: Urška Vrabič-Brodnjak, Klemen Možina
      First page: 94
      Abstract: Invasive plant species can impede the establishment and growth of native plants and affect several ecosystem properties. These properties include soil cover, nutrient cycling, fire regimes, and hydrology. Controlling invasive plants is therefore a necessary, but usually expensive, step in restoring an ecosystem. The sustainability of materials with an emphasis on the use of local resources plays an important role in the circular economy. The use of alternative fibers from invasive plants promotes local production in smaller paper mills that offer the protection of local species and the reduction of waste and invasive plants. A synthesis of the literature is needed to understand the various impacts of invasive plants and their practical control in the context of papermaking applications and to identify associated knowledge gaps. To improve our understanding of the practical application of invasive species in the paper industry, we reviewed the existing literature on invasive plant species in the area of fiber production, printability, coating solution production, dyes, and extracts, and collected information on the major invasive plant species in Europe and the methods used for various applications.
      Citation: Fibers
      PubDate: 2022-10-31
      DOI: 10.3390/fib10110094
      Issue No: Vol. 10, No. 11 (2022)
       
  • Fibers, Vol. 10, Pages 95: Preparation of Side-By-Side Bicomponent Fibers
           Using Bio Polyol Based Thermoplastic Polyurethane (TPU) and TPU/Polylactic
           Acid Blends

    • Authors: Jiyeon Oh, Young Kwang Kim, Sung-Ho Hwang, Hyun-Chul Kim, Jae-Hun Jung, Cho-Hyun Jeon, Jongwon Kim, Sang Kyoo Lim
      First page: 95
      Abstract: In this study, side-by-side bicomponent fibers were prepared by melt spinning using bio-based thermoplastic polyurethane (TPU) and TPU/polylactic acid (PLA) blends. The morphology, thermal and mechanical properties of the fibers were investigated. To this end, the synthesis of TPU using biomass-based polyols and the preparation of TPU/PLA blends were preceded. Their morphological and structural characteristics were investigated. The synthesis of TPU was confirmed through Fourier transform infrared analysis, and as a result of gel permeation chromatograph analysis, a compound having a weight average molecular weight of 196,107 was synthesized. The TPU/PLA blends were blended in the ratio of 80/20, 60/40, 40/60, and 20/80 through a melt extruder. They formed a sea–island structure as a result of scanning electron microscope analysis, and an increase in the PLA content in the TPU matrix caused a decrease in the melt flow index. Finally, TPU/(TPU/PLA) side-by-side bicomponent fibers were prepared by utilizing the above two materials. These fibers exhibited tensile strengths of up to 3624 MPa, with improved biocarbon content of up to 71.5%. These results demonstrate the potential of TPU/(TPU/PLA) side-by-side bicomponent fibers for various applications.
      Citation: Fibers
      PubDate: 2022-11-09
      DOI: 10.3390/fib10110095
      Issue No: Vol. 10, No. 11 (2022)
       
  • Fibers, Vol. 10, Pages 96: Coconut-Fiber Composite Concrete: Assessment of
           Mechanical Performance and Environmental Benefits

    • Authors: Emilio Vélez, Ricardo Rodríguez, Nicolay Bernardo Yanchapanta Gómez, Edgar David Mora, Luis Hernández, Jorge Albuja-Sánchez, María Inés Calvo
      First page: 96
      Abstract: The purpose of this qualification work is to study the physical and mechanical behavior of concrete with the addition of 0.5% and 1% coconut fiber, which has been subjected to two chemical treatments to reduce its degradation. The coconut fibers were extracted from the raw material and cut into pieces 4 cm long. Subsequently, the fibers were subjected to two chemical treatments. The first involved immersing the fibers in 4% sodium hydroxide (NaOH) solution, and the second treatment involved coating them with gum arabic and silica fume. A total of 50 samples of fibers were collected in their natural and post-treated state to be tested. The dosage was prepared for design strengths of 210 and 240 kg/cm2 (20.59 and 23.54 MPa), so that the percentages of 0.5% and 1% volume of coconut fiber, for the two treatments selected, replaced the respective volume of coarse aggregates. The cylinders with 1% addition of fibers had the best performance for the design strength of 20.59 MPa, including the cylinders without fibers. Those with 0.5% addition of fibers presented better performance for the 23.54 MPa dosage, although this was lower than the cylinders without fibers. In all cases, the cylinders with NaOH-treated fibers outperformed their counterparts with fibers treated with gum arabic and silica fume. Finally, a CO2 balance was determined, and an environmental gain up to 14 kg in CO2 emissions was established for each cubic meter of composite concrete.
      Citation: Fibers
      PubDate: 2022-11-09
      DOI: 10.3390/fib10110096
      Issue No: Vol. 10, No. 11 (2022)
       
  • Fibers, Vol. 10, Pages 97: Analysis of Adhesive Distribution over
           Particles According to Their Size and Potential Savings from Particle
           Surface Determination

    • Authors: Jan T. Benthien, Jördis Sieburg-Rockel, Nick Engehausen, Gerald Koch, Jan Lüdtke
      First page: 97
      Abstract: Wood and its processing into particles are, combined, the largest cost factor in the production of particleboard, followed by the cost of adhesive. Thus, reducing their cost is a goal of process optimization. This study investigated whether possible savings could be identified and quantified by determining the particle surface using automated three-dimensional laser-scanning technology (3D Particleview, Fagus-Grecon). The focus was on saving adhesive by sieving out adhesive-consuming fines. It was shown that, currently, with the actual prices for wood (89 €/t), particle preparation (37 €/t), and adhesive (570 €/t), the resulting additional costs for particles are overcompensated by the savings for adhesive with high adhesive content (e.g., 19%). The assumption of uniform distribution of adhesive on the total surface of all particles was checked for correctness using digital reflected light microscopy (VHX-5000, Keyence). Since urea-formaldehyde (UF) adhesive commonly used in particleboard production can only be detected with increased effort, phenol-formaldehyde (PF) adhesive was applied for the tests. Ultraviolet microspectrophotometry (UMSP) was used to rule out excessive penetration of the adhesive into the wooden tissue of the particles. The examination of the distribution of the adhesive over the surface showed that smaller particle sizes tended to be more heavily coated with adhesive. This means that the calculated savings still underestimate the real-life potential or that potential savings exist even with lower adhesive prices or higher prices for wood.
      Citation: Fibers
      PubDate: 2022-11-11
      DOI: 10.3390/fib10110097
      Issue No: Vol. 10, No. 11 (2022)
       
  • Fibers, Vol. 10, Pages 98: Ultrashort Pulse Retrieval from Experimental
           Spectra Transformed in Chalcogenide and Silica Fibers

    • Authors: Elena A. Anashkina, Arseny A. Sorokin, Alexey V. Andrianov
      First page: 98
      Abstract: The characterization of ultrashort optical pulses is a highly requested task. The most popular commercially available hardware/software systems are based on interferometric measurements and second-harmonic generation, leading to some ambiguities and limitations. Here we experimentally test the non-interferometric method of pulse retrieval from three spectra: the fundamental spectrum and two spectra that transformed in an element with Kerr nonlinearity and accumulated different nonlinear phases (different Β-integrals). This method has no ambiguities related to time direction, and allows simple hardware/software implementation. We test a novel simple algorithm for experimental data processing based on the search for a polynomial-approximated spectral phase. Two experimental cases are considered. In the first one, we retrieved 160 fs pulses using a chalcogenide arsenic sulfide glass fiber as a nonlinear Kerr element. In the second case, we retrieved 670 fs pulses with a complex spectrum using a piece of silica-based fiber. The results are confirmed by independent measurements using a standard SHG-FROG technique (Second-Harmonic Generation Frequency-Resolved Optical Gating).
      Citation: Fibers
      PubDate: 2022-11-11
      DOI: 10.3390/fib10110098
      Issue No: Vol. 10, No. 11 (2022)
       
  • Fibers, Vol. 10, Pages 99: Influence of Abaca Fiber Inclusion on the
           Unconfined Compressive Strength of Reconstituted Sandy Silts

    • Authors: Jorge Albuja-Sánchez, Eduardo Alcívar, Daniela Escobar, Juan Montero, Guillermo Realpe, Andrés Muñoz, Mateo Peñaherrera-Aguirre
      First page: 99
      Abstract: The present investigation determines the influence of abaca (Musa textilis) fiber inclusion on the simple compressive strength of reconstituted sandy silt specimens. For this purpose, fibers of different lengths (5, 10 and 15 mm) and quantities (0.5, 1.0, 1.5 and 2.0% of soil dry weight) are added to produce the reconstituted specimens. Subsequently, the physical and mechanical behavior of soil–fiber mixtures were evaluated through compaction and unconfined compression tests. The experimental results showed that increases in fiber content or length, or both, led to a 1235.1% increase in maximum compression stress (compared to the fiber-free soil). Compression failure occurred at a greater axial strain when 10 and 15 mm fibers were added at 1% dosage or in percentages equal to or greater than 1.5% regardless of fiber length. A series of linear mixed models identified statistically significant effects of fiber length and percentage on the level of effort and on the unitary deformation.
      Citation: Fibers
      PubDate: 2022-11-12
      DOI: 10.3390/fib10110099
      Issue No: Vol. 10, No. 11 (2022)
       
  • Fibers, Vol. 10, Pages 100: Permeable Membranes PUR/TETA and PUR/TEPA for
           CO2 Capture Prepared with One-Step Electrospinning Technology

    • Authors: Jakub Hoskovec, Pavla Čapková, Monika Vostiňáková, Petr Ryšánek, Pavel Kaule, Jonáš Tokarský, Oldřich Benada, Vratislav Blechta
      First page: 100
      Abstract: A simple one-step technology of wire electrospinning is presented for the manufacturing of air-permeable CO2-capturing membranes, easily transferable to industrial production lines. The design of the chemically-modified polyurethane nanofiber membranes for CO2 capture was based on a combination of molecular modeling and technological experiments using one-step electrospinning (i.e., a modifying agent dissolved directly in a spinning solution). Polyurethane (PUR Larithane), chemically modified by TETA/TEPA amines, was used in the present study for the membrane design. Special attention was paid to two key parameters significant for the design of the functional unit, i.e., the CO2 sorption capacity and air permeability which depended on the amine concentration. The optimal combination of these parameters was found for the PUR/TEPA membrane (5 wt.% of TEPA in spinning solution): the sorption capacity was 13.97 cm3/g with an air permeability of 0.020 m/s. Molecular modeling proved to be a valuable tool that helped to clarify, at the molecular level, the structure of chemically-modified nanofibrous membranes.
      Citation: Fibers
      PubDate: 2022-11-16
      DOI: 10.3390/fib10110100
      Issue No: Vol. 10, No. 11 (2022)
       
  • Fibers, Vol. 10, Pages 101: Suitability of Surface-Treated Flax and Hemp
           Fibers for Concrete Reinforcement

    • Authors: Ana Caroline da Costa Santos, Paul Archbold
      First page: 101
      Abstract: The use of vegetable fibres as a sustainable alternative to non-natural sources of fibres applied for concrete reinforcement has been studied for over three decades. The main issues about plant-based fibres pointed out by other authors are the variability in their properties and concerns about potential high biodegradability in the alkaline pH of the concrete matrix. Aiming to minimise the variability of flax and hemp fibres, this research compares a range of chemical surface treatments, analysing their effects on the behaviour of the fibres and the effects of their addition to concrete. Corroborating what has been found by other authors, the treatment using NaOH 10% for 24 h was able to enhance the properties of hemp fibre-reinforced concrete and reduce the degradability in alkaline solution. For flax fibres, a novel alternative stood out: treatment using 1% of stearic acid in ethanol for 4 h. Treatment using this solution increased the tensile by 101%, causing a minor effect on the elastic modulus. Concrete mixes reinforced with the treated flax fibres presented reduced thermal conductivity and elastic modulus and increased residual tensile strength and fracture energy.
      Citation: Fibers
      PubDate: 2022-11-17
      DOI: 10.3390/fib10110101
      Issue No: Vol. 10, No. 11 (2022)
       
  • Fibers, Vol. 10, Pages 81: Numerical Study of Mid-IR Ultrashort Pulse
           Reconstruction Based on Processing of Spectra Converted in Chalcogenide
           Fibers with High Kerr Nonlinearity

    • Authors: Arseny A. Sorokin, Alexey V. Andrianov, Elena A. Anashkina
      First page: 81
      Abstract: Ultrashort optical pulses play an important role in fundamental research and applications. It is important to have reliable information about pulse parameters such as duration, intensity profile, and phase. Numerous methods for characterizing pulses in the near-IR range have been well developed by now. However, there is a challenge with pulse measurement in the mid-IR, which is largely related to the underdeveloped component base in this spectral range. We investigate by means of numerical simulations a simple method of pulse reconstruction applicable in the mid-IR. The method is based on measuring and processing only the initial pulse spectrum and two converted spectra in elements with Kerr nonlinearity for different B-integrals characterizing nonlinear phase accumulation. The hardware implementation of the proposed method is very simple. This method requires only a one-dimensional data set, has no moving parts in the optical scheme, and allows for working with high-energy as well as low-energy pulses. We propose a novel simple, efficient, noise-tolerant algorithm for data processing that assumes spectral phase approximation by a polynomial function. We demonstrate numerically the reconstruction of mid-IR ultrashort pulses, namely 3 μm wavelength pulses, using commercial chalcogenide As2S3-based glass fibers as nonlinear elements.
      Citation: Fibers
      PubDate: 2022-09-21
      DOI: 10.3390/fib10100081
      Issue No: Vol. 10, No. 10 (2022)
       
  • Fibers, Vol. 10, Pages 82: Investigating the Mechanical Performance on
           Static and Shock Wave Loading of Aramid Fiber-Reinforced Concrete

    • Authors: Yeou-Fong Li, Hsin-Fu Wang, Jin-Yuan Syu, Gobinathan Kadagathur Ramanathan, Ying-Kuan Tsai
      First page: 82
      Abstract: Fiber-reinforced concrete (FRC) has been used for over a century to improve the mechanical properties of concrete. Kevlar ® 29 fiber (KF) is one of the most popular aramid fibers used in industrial products. This research investigated the effect of the fiber length, the weight ratio of fiber to cement, the mix-proportion of two fiber lengths, and the sizing on the fiber surface on the mechanical properties of Kevlar fiber-reinforced concrete (KFRC) under static, dynamic, and shock wave loadings. Two lengths of chopped KF and three different weight ratios of fiber to cement were mixed in the KFRC specimens for comparison. Moreover, this study also compared how the five mix-proportions of two fiber lengths affected the mechanical properties of mix-proportion KFRC. KF was dispersed by the pneumatic method first, and then, the separated KF was mixed into the concrete to make KFRC. The results indicated that the KFRC specimens with a 10‰ weight ratio of fiber to cement exhibited the maximum compressive, flexural, and splitting tensile strengths, regardless of whether the fiber length was 12 mm or 24 mm. The main finding showed that the specimen mixed with 24 mm KF could endure the highest impact resistance under different impact energies. From the shock wave test, the external damage on the front and rear faces of all KFRC slabs and the KFRC slab reinforced with two layers of KF sheets was less than that of the benchmark slab. The testing results showed that KF greatly enhanced the static and dynamic mechanical performances of concrete, and the KFRC specimen with a 10‰ weight ratio and 24 mm length KF with sizing exhibited the best performance.
      Citation: Fibers
      PubDate: 2022-09-26
      DOI: 10.3390/fib10100082
      Issue No: Vol. 10, No. 10 (2022)
       
  • Fibers, Vol. 10, Pages 83: Mercerization of Agricultural Waste: Sweet
           Clover, Buckwheat, and Rapeseed Straws

    • Authors: Madara Žiganova, Agnese Ābele, Zanda Iesalniece, Remo Merijs Meri
      First page: 83
      Abstract: This research presents the alkali treatment effect on three types of agricultural residues: sweet clover (SCS), buckwheat (BS), and rapeseed straws (RS). The aim of the study was to find the optimal treatment conditions for each straw type, and to assess the potential of sweet clover straw as reinforcement for polymer composites in comparison to buckwheat and rapeseed. The straws were ground and treated for 15, 30, and 60 min using NaOH at concentrations of 2, 5, and 10%. To investigate the treatment results on the SCS, BS, and RS fibers, Fourier transform infrared spectroscopy, scanning electron microscopy, optical microscope, X-ray diffraction, and thermogravimetric analysis were used. Results indicate that the optimal room-temperature alkaline-treatment conditions of SCS fibers were the same as those for RS treated with 2% NaOH solution for 30 min. These conditions were milder in comparison to those used for the treatment of BS: 60 min in a 5% NaOH solution. During the treatment, noncellulosic substances were largely removed, and the aspect ratio of the fibers was increased, and the destruction temperature, crystallinity, and morphology were also affected. Consequently, SCS has promising potential for use in polymer composites.
      Citation: Fibers
      PubDate: 2022-09-28
      DOI: 10.3390/fib10100083
      Issue No: Vol. 10, No. 10 (2022)
       
  • Fibers, Vol. 10, Pages 84: Laboratory Investigation of Sand-Geosynthetic
           Interface Friction Parameters Using Cost-Effective Vertical Pullout
           Apparatus

    • Authors: Malik Rizwan, Hassan Mujtaba, Khalid Farooq, Zia Ur Rehman, Syed Zishan Ashiq, Syed Minhaj Saleem Kazmi, Muhammad Junaid Munir
      First page: 84
      Abstract: The current research has been carried out to investigate the interactive behaviour of soil-geosynthetic interfaces. A cost-effective vertical pullout test (VPT) apparatus was designed for this purpose. A series of laboratory direct shear tests (DSTs) and vertical pullout tests (VPT) were carried out using three types of sands and four different types of geosynthetics. All three sandy samples used in this research were classified as poorly graded sand (SP) as per the Unified Soil Classification System (USCS) with median grain size ranging between 0.39~0.2 mm. The geosynthetics used were three woven and one non-woven with a tensile force of 3.3 kN/m~103.8 kN/m. The direct shear test revealed that geometric properties of geosynthetics have an influence on interface shear resistance. Interface friction angle varies between 29.2~38.3. Vertical pullout (VPT) test results show that the pullout force is in the range of 23.9~31.4. The interface friction angle by both direct and vertical pullout tests is more for coarse-grained soils than for fine-grained soils. Interface friction angles from pullout tests were around 19% smaller than direct shear tests. The interface efficiency ranged from 0.69 to 0.97 for all soils; meanwhile, for non-woven geotextiles, the efficiency values are up to 22% higher as compared to woven geotextiles due to theirtexture. The present research indicates that interface friction parameters can be efficiently determined through the interface of a cost-effective VPT which is also comparable with DST. The reliable values of interface efficiency can be obtained for soil-geosynthetic interfaces which can optimize the design and omits the need forassumed conservative values of friction parameters.
      Citation: Fibers
      PubDate: 2022-09-30
      DOI: 10.3390/fib10100084
      Issue No: Vol. 10, No. 10 (2022)
       
  • Fibers, Vol. 10, Pages 85: Valorization of Potential Post-Consumer
           Polyethylene (PE) Plastics Waste and Ethiopian Indigenous Highland Bamboo
           (EHB) for Wood Plastic Composite (WPC): Experimental Evaluation and
           Characterization

    • Authors: Keresa Defa Ayana, Marco De Angelis, Goran Schmidt, Andreas Krause, Abubeker Yimam Ali
      First page: 85
      Abstract: The best approaches to minimizing resource scarcity, removing valuable waste streams, and re-establishing a circular economic chain of recycled thermoplastics are to cascade them into product life cycles and their valorization combined with sustainable raw materials. As one part of this goal, WPC was formulated from three recycled PE plastic wastes: linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), and underutilized EHB. The chemical composition of EHD, chemical structure, crystallinity, melting and crystallization points, residual metal additives, and polycyclic aromatic hydrocarbons (PAHs) of recycled PE were investigated using standard chromatographic and spectroscopic methods such as HPAEC-UV/VIS, FTIR, DSC, GC/MSD, and XPS. The properties of WPC formulations from different compositions of bamboo particles (BP) as dispersed phase, individual recycled PE plastics, and equal melt blend (EM) as polymer matrix were investigated extensively and measured with a known standard. These comprised tensile strength (TS), modulus of elasticity (TM), flexural strength (FS), modulus of rupture (FM), and unnotched impact strength (UIS). It also included the effect of various alkaline surface treatment ranges on the interface surface interaction. The results show improved mechanical properties for all blending ratios of surface-treated BP, which resulted from better encapsulation in the polymer matrix. Despite its inherent immiscibility, WPC formulation from equal melt blending revealed unusual properties compared to separate phase blends, which is attributed to thermally induced cross-linking. This implies that melt blending of the weakest and cheapest recycled LLDPE with relatively cheap recycled MDPE and HDPE improves the properties of the blend, particularly toughness, while simultaneously retaining some of their properties.
      Citation: Fibers
      PubDate: 2022-10-08
      DOI: 10.3390/fib10100085
      Issue No: Vol. 10, No. 10 (2022)
       
  • Fibers, Vol. 10, Pages 86: Flexural Strengthening of Reinforced Concrete
           Beams with Variable Compressive Strength Using Near-Surface Mounted
           Carbon-Fiber-Reinforced Polymer Strips [NSM-CFRP]

    • Authors: Hebah Al-zu’bi, Mu’tasim Abdel-Jaber, Hasan Katkhuda
      First page: 86
      Abstract: An experimental and analytical investigation was conducted on reinforced concrete (RC) beams strengthened in flexure using the near-surface mounted carbon-fiber-reinforced polymers (NSM-CFRPs) technique. A total of 11 full-scale RC rectangular beams were cast and tested under a monotonic three-point bending test, up to failure. The main test variables adopted in this study were the concrete compressive strength (high, medium, and low), the number of CFRP strips, and the strip length. The results indicated that the use of NSM-CFRPs strips in different configurations efficiently increased the load-carrying capacity of the strengthened RC beams, in which all these beams exhibited a higher moment resistance than the corresponding un-strengthened beam. Results also showed that all strengthening schemes were successful in increasing the flexural capacity of the specimens tested. Such increases ranged between 10.36% and 52.28%. Notably, a significant improvement in the ultimate load ratio was observed with beams having a low compressive strength of 17-MPa, then followed by the beams with medium strength (32-MPa), and finally beams with high compressive strength (47-MPa). The NSM technique reduced the occurrence possibility of the CFRP de-bonding failure mode. Furthermore, the test results were compared with theoretical predictions using the ACI 440.2R17 guidelines and showed a good agreement between these results.
      Citation: Fibers
      PubDate: 2022-10-13
      DOI: 10.3390/fib10100086
      Issue No: Vol. 10, No. 10 (2022)
       
  • Fibers, Vol. 10, Pages 87: A Unique Crustacean-Based Chitin Platform to
           Reduce Self-Aggregation of Polysaccharide Nanofibers

    • Authors: Carolina Londoño-Zuluaga, Hasan Jameel, Ronalds Gonzalez, Kimberly Nellenbach, Ashley Brown, Guihua Yang, Lucian Lucia
      First page: 87
      Abstract: Every year, over 8 million tons of crustacean shells are discarded. However, there exists an opportunity for valorizing the chitin and calcium carbonate part of the composition of the shells. Our study revealed crustacean chitin reduces self-aggregation effects. It was shown that crustacean-based nanofibers alone or added to cellulose offer unprecedented reductions in viscosity even after drying to produce foams impossible for cellulose. Polysaccharide nanofibers suffer from increased viscosity from strong hydrogen bonding addressed by the incorporation of crustacean-based nanofibers. The ability of the nanocomposite to overcome self-aggregation and collapse was attributed to organized chitin nanofiber morphology in the crustacean matrix. As a result of enhanced surface area from reduced fiber aggregation, the chitin/crustacean-cellulose blend was tested for a biomedical application requiring a high surface area: coagulation. Preliminary experiments showed the crustacean matrices, especially those containing calcium carbonate, induced blood clotting when 35 s. A materials platform is proposed for bio-based nanofiber production overcoming intractable and difficult-to-address self-aggregation effects associated with polysaccharides.
      Citation: Fibers
      PubDate: 2022-10-14
      DOI: 10.3390/fib10100087
      Issue No: Vol. 10, No. 10 (2022)
       
  • Fibers, Vol. 10, Pages 88: Analysis of the Passive Stabilization Methods
           of Optical Frequency Comb in Ultrashort-Pulse Erbium-Doped Fiber Lasers

    • Authors: Stanislav G. Sazonkin, Ilya O. Orekhov, Dmitriy A. Dvoretskiy, Uliana S. Lazdovskaia, Almikdad Ismaeel, Lev K. Denisov, Valeriy E. Karasik
      First page: 88
      Abstract: In this review paper, we describe the current state of the art to stabilize the output radiation of ultrashort-pulse (USP) fiber lasers and analyze passive methods to reduce the magnitude of fluctuations in the amplitude–frequency noise of output radiation. Regarding main noise characterization in mode-locked fiber lasers, we further consider the influence on laser operation of primary generation regimes starting up in cavities, such as solitons, stretched pulses, similaritons, and dissipative solitons. Then, we proceed to analyze the external and internal factors that affect the stability of the output radiation characteristics depending on the mode-locking mechanism and the resonator scheme.
      Citation: Fibers
      PubDate: 2022-10-14
      DOI: 10.3390/fib10100088
      Issue No: Vol. 10, No. 10 (2022)
       
  • Fibers, Vol. 10, Pages 89: Propagation of Terahertz Surface Plasmon
           Polaritons in a Dielectric Fiber with a Metal Wire Core

    • Authors: Nikolai I. Petrov
      First page: 89
      Abstract: The influence of the conductivity and radius of metal wires embedded into the dielectric fiber on the velocity and attenuation length of terahertz surface plasmon polaritons has been theoretically investigated. It was shown that the phase velocities and attenuation lengths increase with increasing conductivity and radius of the wire. With increasing frequency, the velocity of surface plasmon waves increases and the propagation length decreases. The effect of the dielectric coating on the propagation velocity of surface electromagnetic waves is analyzed. It is shown that the coating leads to a decrease in the phase velocity and an increase in the propagation length of surface plasmon waves.
      Citation: Fibers
      PubDate: 2022-10-19
      DOI: 10.3390/fib10100089
      Issue No: Vol. 10, No. 10 (2022)
       
  • Fibers, Vol. 10, Pages 90: Wavelength Sensing Based on Whispering Gallery
           Mode Mapping

    • Authors: Roberts Berkis, Pauls Kristaps Reinis, Lase Milgrave, Kristians Draguns, Toms Salgals, Inga Brice, Janis Alnis, Aigars Atvars
      First page: 90
      Abstract: We demonstrate a wavelength sensor based on whispering gallery mode (WGM) resonators. For the first time, multiple polymethyl methacrylate (PMMA) microspheres were simultaneously attached to a tapered fiber. WGM resonances from these commercially available PMMA microspheres were observed with a NIR camera, monitoring the scattered light. Circulating light in the WGMs was scattered on the outer layer of the microspheres and appeared as bright spots due to scattering defects. For each laser wavelength fed into the tapered fiber, the light interfered differently for the various sizes of PMMA microspheres. We measured scattered light intensity for different wavelengths and created a barcode for each microsphere. Combining these barcodes into a mode map allowed for unknown wavelength detection. A tunable laser around 1550 nm was used for measurements. As a result, a laser wavelength sensor system with a detection limit of 5 pm was demonstrated. The principles of increasing selectivity, as well as creating a compact device, were discussed.
      Citation: Fibers
      PubDate: 2022-10-19
      DOI: 10.3390/fib10100090
      Issue No: Vol. 10, No. 10 (2022)
       
  • Fibers, Vol. 10, Pages 91: Production and 3D Printing of a
           Nanocellulose-Based Composite Filament Composed of Polymer-Modified
           Cellulose Nanofibrils and High-Density Polyethylene (HDPE) for the
           Fabrication of 3D Complex Shapes

    • Authors: Feras Dalloul, Jakob Benedikt Mietner, Julien R. G. Navarro
      First page: 91
      Abstract: This work aims to produce a 3D-printable bio-based filament composed of high-density polyethylene (HDPE) and chemically modified cellulose nanofibrils. Printing using HDPE as a raw material is challenging due to its massive shrinkage and warping problems. This paper presents a new method to overcome those difficulties by enhancing the mechanical properties and achieving better print quality. This was achieved using modified cellulose nanofibrils (CNFs) as fillers. Firstly, CNF was converted to a CNF-based macroinitiator through an esterification reaction, followed by a surface-initiated single-electron transfer living radical polymerization (SI-SET-LRP) of the hydrophobic monomer stearyl acrylate. Poly stearyl acrylate-grafted cellulose nanofibrils, CNF-PSAs, were synthesized, purified and characterized with ATR-FTIR, 13C CP-MAS NMR, FE-SEM and water contact angle measurements. A composite was successfully produced using a twin-screw extruder with a CNF-PSA content of 10 wt.%. Mechanical tests were carried out with tensile testing. An increase in the mechanical properties, up to 23% for the Young’s modulus, was observed. A morphologic analysis also revealed the good matrix/CNF compatibility, as no CNF aggregates could be observed. A reduction in the warping behavior for the composite filament compared to HDPE was assessed using a circular arc method. The 3D printing of complex objects using the CNF-PSA/HDPE filament resulted in better print quality when compared to the object printed with neat HDPE. Therefore, it could be concluded that CNF-PSA was a suitable filler for the reinforcement of HDPE, thus, rendering it suitable for 3D printing.
      Citation: Fibers
      PubDate: 2022-10-21
      DOI: 10.3390/fib10100091
      Issue No: Vol. 10, No. 10 (2022)
       
  • Fibers, Vol. 10, Pages 92: Angular Momentum of Leaky Modes in Hollow-Core
           Fibers

    • Authors: Grigory Alagashev, Sergey Stafeev, Victor Kotlyar, Andrey Pryamikov
      First page: 92
      Abstract: It is known that angular momentum (AM) is an important characteristic of light, which can be separated into the spin (SAM) and orbital parts (OAM). The dynamical properties of the spin and orbital angular momentums are determined by the polarization and spatial degrees of freedom of light. In addition to optical vortex beams possessing spatial polarization and phase singularities, optical fibers can be used to generate and propagate optical modes with the orbital and spin parts of the angular momentum. In this paper, using the example of hollow-core fibers, we demonstrate the fact that their leaky air core modes also have an orbital part of AM in the case of circular polarization arising from the spin–orbit interaction of the air core modes. The reason for the appearance of AM is the leakage of the air core mode energy.
      Citation: Fibers
      PubDate: 2022-10-21
      DOI: 10.3390/fib10100092
      Issue No: Vol. 10, No. 10 (2022)
       
 
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