Subjects -> TEXTILE INDUSTRIES AND FABRICS (Total: 41 journals)


Showing 1 - 16 of 16 Journals sorted alphabetically
AATCC Journal of Research     Full-text available via subscription   (Followers: 13)
AATCC Review     Full-text available via subscription   (Followers: 4) - Revista Eletrônica de Moda     Open Access  
Asian Journal of Textile     Open Access   (Followers: 14)
Autex Research Journal     Open Access   (Followers: 4)
Cerâmica     Open Access   (Followers: 6)
Composites Science and Technology     Hybrid Journal   (Followers: 245)
Fashion and Textiles     Open Access   (Followers: 20)
Fashion Practice : The Journal of Design, Creative Process & the Fashion     Hybrid Journal   (Followers: 15)
Fibers     Open Access   (Followers: 8)
Fibre Chemistry     Hybrid Journal   (Followers: 4)
Focus on Pigments     Full-text available via subscription   (Followers: 4)
Geosynthetics International     Hybrid Journal   (Followers: 5)
Geotextiles and Geomembranes     Hybrid Journal   (Followers: 6)
Indian Journal of Fibre & Textile Research (IJFTR)     Open Access   (Followers: 15)
International Journal of Fashion Design, Technology and Education     Hybrid Journal   (Followers: 17)
International Journal of Textile Science     Open Access   (Followers: 15)
Journal of Engineered Fibers and Fabrics     Open Access   (Followers: 3)
Journal of Fashion Technology & Textile Engineering     Hybrid Journal   (Followers: 10)
Journal of Industrial Textiles     Hybrid Journal   (Followers: 6)
Journal of Leather Science and Engineering     Open Access   (Followers: 1)
Journal of Natural Fibers     Hybrid Journal   (Followers: 7)
Journal of Textile Design Research and Practice     Full-text available via subscription   (Followers: 7)
Journal of Textile Science & Engineering     Open Access   (Followers: 6)
Journal of The Institution of Engineers (India) : Series E     Hybrid Journal   (Followers: 2)
Journal of the Textile Institute     Hybrid Journal   (Followers: 12)
Research Journal of Textile and Apparel     Full-text available via subscription   (Followers: 1)
Text and Performance Quarterly     Hybrid Journal   (Followers: 5)
Textile History     Hybrid Journal   (Followers: 21)
Textile Progress     Hybrid Journal   (Followers: 6)
Textile Research Journal     Hybrid Journal   (Followers: 14)
Textiles and Clothing Sustainability     Open Access   (Followers: 4)
Textiles and Light Industrial Science and Technology     Open Access   (Followers: 5)
Third Text     Hybrid Journal   (Followers: 11)
Wearables     Open Access   (Followers: 2)
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Number of Followers: 8  

  This is an Open Access Journal Open Access journal
ISSN (Online) 2079-6439
Published by MDPI Homepage  [238 journals]
  • Fibers, Vol. 9, Pages 53: Photosensitive Yb-Doped Germanophosphosilicate
           Artificial Rayleigh Fibers as a Base of Random Lasers

    • Authors: Andrey Rybaltovsky, Sergei Popov, Denis Lipatov, Andrey Umnikov, Alexey Abramov, Oleg Morozov, Dmitry Ryakhovskiy, Viktor Voloshin, Alexander Kolosovskii, Igor Vorob’ev, Oleg Butov, Yuriy Chamorovskiy
      First page: 53
      Abstract: Asingle-mode Yb-doped germanophosphosilicate fiber with ultra-low optical losses (less than 2 dB/km) was fabricated by means of the MCVD method utilizing an all-gas-phase deposition technique developed “in house”. The absorption and luminescent spectral properties of the fiber were thoroughly studied. The photosensitivity of the pristine (non-hydrogenated) fiber to 248 nm-laser radiation was confirmed by means of fiber Bragg grating (FBG) inscription directly during the drawing process. The random single-frequency lasing at the 1060-nm-wavelength obtained in the 21-m-long fiber with an array of weak FBG was reported. The developed laser slope efficiency in the backward-pumping scheme was measured as high as 32%.
      Citation: Fibers
      PubDate: 2021-09-01
      DOI: 10.3390/fib9090053
      Issue No: Vol. 9, No. 9 (2021)
  • Fibers, Vol. 9, Pages 54: Insight into the Effects of Solvent Treatment of
           Natural Fibers Prior to Structural Composite Casting: Chemical, Physical
           and Mechanical Evaluation

    • Authors: Ali Abbass, Maria C. Paiva, Daniel V. Oliveira, Paulo B. Lourenço, Raul Fangueiro
      First page: 54
      Abstract: This paper presents an optimized washing protocol for as-received natural fibers, prior to large-scale composite manufacturing, for the structural strengthening of historic masonry. The aim was to achieve a simple protocol for standard cleaning of fiber surfaces from low molecular weight constituents that may be detrimental towards interfacial strength without damaging the fibers. The proposed procedure employs the application of the solvent sequence: ethanol, acetone, hexane, with optimized incubation times and stirring conditions. Additionally, this procedure may change the surface of the fiber, thereby enhancing the durability of the fiber-matrix interface. The washing protocol resulted in an increase of tensile strength by 56%, 52% and 22% for flax, hemp and sisal fibers, respectively, as compared to the corresponding non-washed fibers, without loss of elongation. The static contact angle measurements confirmed exposure of a higher fraction of the hydrophilic crystalline cellulose, with a higher wettability observed after washing protocols.
      Citation: Fibers
      PubDate: 2021-09-01
      DOI: 10.3390/fib9090054
      Issue No: Vol. 9, No. 9 (2021)
  • Fibers, Vol. 9, Pages 55: Sustainably Processed Waste Wool

    • Authors: Parag Bhavsar, Tudor Balan, Giulia Dalla Fontana, Marina Zoccola, Alessia Patrucco, Claudio Tonin
      First page: 55
      Abstract: In the EU, sheep bred for dairy and meat purposes are of low quality, their economic value is not even enough to cover shearing costs, and their wool is generally seen as a useless by-product of sheep farming, resulting in large illegal disposal or landfilling. In order to minimize environmental and health-related problems considering elemental compositions of discarded materials such as waste wool, there is a need to recycle and reuse waste materials to develop sustainable innovative technologies and transformation processes to achieve sustainable manufacturing. This study aims to examine the application of waste wool in biocomposite production with the help of a sustainable hydrolysis process without any chemicals and binding material. The impact of superheated water hydrolysis and mixing hydrolyzed wool fibers with kraft pulp on the performance of biocomposite was investigated and characterized using SEM, FTIR, tensile strength, DSC, TGA, and soil burial testing in comparison with 100% kraft pulp biocomposite. The superheated water hydrolysis process increases the hydrophilicity and homogeneity and contributes to increasing the speed of biodegradation. The biocomposite is entirely self-supporting, provides primary nutrients for soil nourishment, and is observed to be completely biodegradable when buried in the soil within 90 days. Among temperatures tested for superheated water hydrolysis of raw wool, 150 °C seems to be the most appropriate for the biocomposite preparation regarding physicochemical properties of wool and suitability for wool mixing with cellulose. The combination of a sustainable hydrolysis process and the use of waste wool in manufacturing an eco-friendly, biodegradable paper/biocomposite will open new potential opportunities for the utilization of waste wool in agricultural and packaging applications and minimize environmental impact.
      Citation: Fibers
      PubDate: 2021-09-01
      DOI: 10.3390/fib9090055
      Issue No: Vol. 9, No. 9 (2021)
  • Fibers, Vol. 9, Pages 56: Advanced Composite Retrofit of RC Columns and
           Frames with Prior Damages—Pseudodynamic Finite Element Analyses and
           Design Approaches

    • Authors: Theodoros Rousakis, Evgenia Anagnostou, Theodora Fanaradelli
      First page: 56
      Abstract: This study develops three-dimensional (3D) finite element (FE) models of composite retrofits in deficient reinforced concrete (RC) columns and frames. The aim is to investigate critical cases of RC columns with inadequate lap splices of bars or corroded steel reinforcements and the beneficial effects of external FRP jacketing to avoid their premature failure and structural collapse. Similarly, the RC-frame FE models explore the effects of an innovative intervention that includes an orthoblock brick infill wall and an advanced seismic joint made of highly deformable polymer at the boundary interface with the RC frame. The experimental validation of the technique in RC frames is presented in earlier published papers by the authors (as well as for a four-column structure), revealing the potential to extend the contribution of the infills at high displacement ductility levels of the frames, while exhibiting limited infill damages. The analytical results of the advanced FE models of RC columns and frames compare well with the available experimental results. Therefore, this study’s research extends to critical cases of FE models of RC frames with inadequate lap splices or corroded steel reinforcements, without or with brick wall infills with seismic joints. The advanced pseudodynamic analyses reveal that for different reinforcement detailing of RC columns, the effects of inadequate lap-spliced bars may be more detrimental in isolated RC columns than in RC frames. It seems that in RC frames, additional critical regions without lap splices are engaged and redistribution of damage is observed. The detrimental effects of corroded steel bars are somewhat greater in bare RC frames than in isolated RC columns, as all reinforcements in the frame are considered corroded. Further, all critical cases of RC frames with prior damages at risk of collapse may receive the innovative composite retrofit and achieve higher base shear load than the original RC frame without corroded or lap-spliced bars, at comparable top displacement ductility. Finally, the FE analyses are utilized to propose modified design equations for the shear strength and chord rotation in cases of failure of columns with deficiencies or prior damages in RC structures.
      Citation: Fibers
      PubDate: 2021-09-06
      DOI: 10.3390/fib9090056
      Issue No: Vol. 9, No. 9 (2021)
  • Fibers, Vol. 9, Pages 57: Carboxymethyl Cellulose Enhanced Production of
           Cellulose Nanofibrils

    • Authors: Yunsang Kim, Lauren T. McCoy, Corbin Feit, Shuaib A. Mubarak, Suraj Sharma, Sergiy Minko
      First page: 57
      Abstract: Cellulose nanofibrils (CNF) were produced by high-pressure homogenization from kraft pulp in the presence of carboxymethyl cellulose (CMC) of varying molecular weights. CNF pretreated with 250 kD CMC exhibited the maximum specific surface area (SSA) of 641 m2/g, which is comparable to that of CNF pretreated by 2,2,6,6-tetramethyl-piperidinyl-1-oxyl (TEMPO)-meditated oxidation with a high degree of fibrillation. Rheological and microscopic analyses also indicated a high level of fibrillation for the CMC-pretreated CNF. In contrast, the reference CNF without the CMC pretreatment showed a lower level of fibrillation, which was reflected in decreased viscosity and the reduction of SSA by a factor of 19. With the high-degree fibrillation and low toxicity, the CMC pretreatment is a promising method for the production of high-quality CNF in an environmentally friendly way.
      Citation: Fibers
      PubDate: 2021-09-13
      DOI: 10.3390/fib9090057
      Issue No: Vol. 9, No. 9 (2021)
  • Fibers, Vol. 9, Pages 47: Hazardous Elements in Asbestos Tremolite from
           the Basilicata Region, Southern Italy: A First Step

    • Authors: Claudia Ricchiuti, Dolores Pereira, Rosalda Punturo, Eugenia Giorno, Domenico Miriello, Andrea Bloise
      First page: 47
      Abstract: In this paper, we report the quantification of potentially toxic elements (PTEs) hosted into two tremolite asbestos from Episcopia and San Severino Lucano villages (Basilicata region, Southern Italy). Micro X-ray fluorescence and Inductively Coupled Plasma spectroscopy with Optical Emission Spectrometry techniques were used to quantify the concentration of major, minor (Si, Mg, Ca, Al, Fe, Mn) and trace elements (As, Ba, Cd, Co, Cr, Cu, Li, Mo, Ni, Pb, Sb, Sn Sr, Ti, Te, V, W, Zn, Zr), with the aim of providing available data useful for the determination of the asbestos fibers toxicity. Results show that in the two studied samples there exist high concentrations of Fe, Mn, Cr and Ni which could lead to the high toxicity of the mineral fibers. By considering the pseudo-total PTEs amounts in each tremolite asbestos, it is possible to affirm that one of the samples is more enriched in toxic elements than the other one (3572 ppm versus 1384 ppm). These PTEs can represent a source of risk to human health since they may be transported away from the geological outcrops, through asbestos in the air, water and soils and thus encountering the human body.
      Citation: Fibers
      PubDate: 2021-08-01
      DOI: 10.3390/fib9080047
      Issue No: Vol. 9, No. 8 (2021)
  • Fibers, Vol. 9, Pages 48: Effect of Nanoclay Addition on the Morphology,
           Fiber Size Distribution and Pore Size of Electrospun Polyvinylpyrrolidone
           (PVP) Composite Fibers for Air Filter Applications

    • Authors: Iman Azarian Borojeni, Arash Jenab, Mehdi Sanjari, Charles Boudreault, Michael Klinck, Scott Strong, A. Reza Riahi
      First page: 48
      Abstract: The fabrication of Polyvinylpyrrolidone (PVP) electrospun layers for air filter applications is the target of this study. Solutions of 10% PVP containing 0, 3, 10 and 25 wt% nanoclay were used to fabricate electrospun fibers. Scanning electron microscopy showed that the fibers’ roughness increased by increasing the nanoclay content, and it was maximum at the nanoclay concentration of 25 wt%. Concurrently, nanoclay decreased the pore size considerably and increased the range of the fibers’ size distribution up to 100%. In addition, as the nanoclay concentration increased, the frequency distribution decreased abruptly for the larger fiber sizes and increased dramatically for the small fiber sizes. This phenomenon was correlated to the effect of nanoclay concentration on the conductivity of the solution. The solution’s conductivity increased from 1.7 ± 0.05 µS/cm for the PVP solution without nanoclay to 62.7 ± 0.19 µS/cm for the solution containing 25 wt% nanoclay and destabilized the electrospun jet, increasing the range of fiber size distribution. Therefore, the PVP solution containing 25 wt% nanoclay has potential characteristics suitable for air-filter applications, owing to its rougher fibers and combination of fine and thicker fibers.
      Citation: Fibers
      PubDate: 2021-08-01
      DOI: 10.3390/fib9080048
      Issue No: Vol. 9, No. 8 (2021)
  • Fibers, Vol. 9, Pages 49: Effect of Alkali Treatment on the Properties of
           Acacia Caesia Bark Fibres

    • Authors: Palanisamy Sivasubramanian, Mayandi Kalimuthu, Murugesan Palaniappan, Azeez Alavudeen, Nagarajan Rajini, Carlo Santulli
      First page: 49
      Abstract: As possible substitutes for non-biodegradable synthetic fibre, ligno-cellulosic fibres have attracted much interest for their eco-friendliness; a large number of them are already used for the production of green polymer composites. The search for further green candidates brings into focus other fibres not previously considered, yet part of other production systems, therefore available as by-products or refuse. The purpose of this study is to explore the potential of alkali treatment with 5% sodium hydroxide (NaOH) to enhance the properties of bark-extracted Acacia Caesia Bark (ACB) fibres. The microscopic structure of the treated fibres was elucidated using scanning electron microscopy (SEM). Moreover, the fibres were characterised in terms of chemical composition and density and subjected to single-fibre tensile tests (SFTT). Following their physico-chemical characterisation, fibre samples underwent thermal characterisation by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), and their crystallinity was assessed using X-ray diffraction (XRD). This level of alkali treatment only marginally modified the structure of the fibres and offered some improvement in their tensile strength. This suggested that they compare well with other bark fibres and that their thermal profile showed some increase of degradation onset temperature with respect to untreated ACB fibres. Their crystallinity would allow their application in the form of fibres with an average length of approximately 150 mm, even in thermoplastic biocomposites.
      Citation: Fibers
      PubDate: 2021-08-02
      DOI: 10.3390/fib9080049
      Issue No: Vol. 9, No. 8 (2021)
  • Fibers, Vol. 9, Pages 50: Framework for Predicting Failure in Polymeric
           Unidirectional Composites through Combined Experimental and Computational
           Mesoscale Modeling Techniques

    • Authors: Bilal Khaled, Loukham Shyamsunder, Josh Robbins, Yatin Parakhiya, Subramaniam D. Rajan
      First page: 50
      Abstract: As composites continue to be increasingly used, finite element material models that homogenize the composite response become the only logical choice as not only modeling the entire composite microstructure is computationally expensive but obtaining the entire suite of experimental data to characterize deformation and failure may not be possible. The focus of this paper is the development of a modeling framework where plasticity, damage, and failure-related experimental data are obtained for each composite constituent. Mesoscale finite elements models consisting of multiple repeating unit cells are then generated and used to represent a typical carbon fiber/epoxy resin unidirectional composite to generate the complete principal direction stress-strain curves. These models are subjected to various uniaxial states of stress and compared with experimental data. They demonstrate a reasonable match and provide the basic framework to completely define the composite homogenized material model that can be used as a vehicle for failure predictions.
      Citation: Fibers
      PubDate: 2021-08-02
      DOI: 10.3390/fib9080050
      Issue No: Vol. 9, No. 8 (2021)
  • Fibers, Vol. 9, Pages 51: Mechanical and Structural Characterization of
           Pineapple Leaf Fiber

    • Authors: Eric Worlawoe Gaba, Bernard O. Asimeng, Elsie Effah Kaufmann, Solomon Kingsley Katu, E. Johan Foster, Elvis K. Tiburu
      First page: 51
      Abstract: Evidence-based research had shown that elevated alkali treatment of pineapple leaf fiber (PALF) compromised the mechanical properties of the fiber. In this work, PALF was subjected to differential alkali concentrations: 1, 3, 6, and 9% wt/wt to study the influence on the mechanical and crystal properties of the fiber. The crystalline and mechanical properties of untreated and alkali-treated PALF samples were investigated by X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR), and tensile testing analysis. The XRD results indicated that crystal properties of the fibers were modified with 6% wt/wt alkali-treated PALF recording the highest crystallinity and crystallite size of 76% and 24 nm, respectively. The FTIR spectra suggested that all alkali-treated PALF samples underwent lignin and hemicellulose removal to varying degrees. An increase in the crystalline properties improved the mechanical properties of the PALF treated with alkali at 6% wt/wt, which has the highest tensile strength (1620 MPa). Although the elevated alkali treatment resulted in decreased mechanical properties of PALF, crystallinity generally increased. The findings revealed that the mechanical properties of PALF not only improve with increasing crystallinity and crystallite size, but are also dependent on the intermediate bond between adjacent cellulose chains.
      Citation: Fibers
      PubDate: 2021-08-06
      DOI: 10.3390/fib9080051
      Issue No: Vol. 9, No. 8 (2021)
  • Fibers, Vol. 9, Pages 52: Critical Factors for Optimum Biodegradation of
           Bast Fiber’s Gums in Bacterial Retting

    • Authors: Mohammad Munir Hossain, Shafiquzzaman Siddiquee, Vijay Kumar
      First page: 52
      Abstract: Bast fiber plants require a post-harvest process to yield useable natural cellulosic fibers, denoted as retting or degumming. It encompasses the degradation of the cell wall’s non-cellulosic gummy substances (NCGs), facilitating fibers separations, setting the fiber’s quality, and determining downstream usages. Due to the inconvenience of traditional retting practices, bacterial inoculum and enzyme applications for retting gained attention. Therefore, concurrent changes of agroclimatic and socioeconomic conditions, the conventional water retting confront multiple difficulties, bast industries become vulnerable, and bacterial agents mediated augmented bio-retting processes trying to adapt to sustainability. However, this process’s success demands a delicate balance among substrates and retting-related biotic and abiotic factors. These critical factors were coupled to degrade bast fibers NCGs in bacterial retting while holistically disregarded in basic research. In this study, a set of factors were defined that critically regulates the process and requires to be comprehended to achieve optimum retting without failure. This review presents the bacterial strain characteristics, enzyme potentials, specific bast plant cell wall’s structure, compositions, solvents, and interactions relating to the maximum NCGs removal. Among plants, associated factors pectin is the primary biding material that determines the process’s dynamics, while its degree of esterification has a proficient effect through bacterial enzymatic degradation. The accomplished bast plant cell wall’s structure, macerating solvents pH, and temperature greatly influence the bacterial retting process. This article also highlights the remediation process of water retting pollution in a biocompatible manner concerning the bast fiber industry’s endurance.
      Citation: Fibers
      PubDate: 2021-08-12
      DOI: 10.3390/fib9080052
      Issue No: Vol. 9, No. 8 (2021)
  • Fibers, Vol. 9, Pages 40: Effects of Microwave Treatment in Immersed
           Conditions on the Mechanical Properties of Jute Yarn

    • Authors: Felicia Syrén, Joel Peterson, Nawar Kadi
      First page: 40
      Abstract: The versatile bast fiber jute has environmental benefits compared to glass fibers. However, for jute to be used in a composite, the fiber properties need to be altered. This study aims to improve the mechanical properties of jute yarn to make it more suitable for technical applications as a composite. To alter its mechanical properties, jute yarn was immersed in water during microwave treatment. The time and power of the microwave settings differed between runs. Two states of the yarn were tested: fastened and un-fastened. Tensile testing was used at the yarn and fiber level, followed by Fourier-transform infrared spectroscopy (FTIR) and microscopy. The treatment result demonstrated the ability to increase the elongation of the jute yarn by 70%. The tenacity was also increased by 34% in the fastened state and 20% in the un-fastened state. FTIR showed that no change in the molecular structure occurred. The treatments resulted in a change of yarn thickness depending on the state of the yarn. The results indicate that microwave treatment can be used to make jute more suitable for technical applications depending on the microwave treatment parameters.
      Citation: Fibers
      PubDate: 2021-07-01
      DOI: 10.3390/fib9070040
      Issue No: Vol. 9, No. 7 (2021)
  • Fibers, Vol. 9, Pages 41: Optimising the Workability and Strength of
           Concrete Modified with Anacardium Occidentale Nutshell Ash

    • Authors: Solomon Oyebisi, Anthony Ede, Hilary Owamah, Tobit Igba, Oluwaseun Mark, Abimbola Odetoyan
      First page: 41
      Abstract: Strength failure persists both in structural and mechanical analysis. One of its prominent characteristics is the adequate provision for parameters that minimise or maximise strength objectives while satisfying boundary conditions. The previous optimisation of concrete strength usually neglects mix design mechanisms induced by optimisation. Recent efforts to accurately optimise the concrete compressive strength have factored in some of these mechanisms. However, optimising concrete strength modified with high silica and alumina precursors, and crucial mix design factors are rare. Consequently, this paper optimised the concrete workability and strength, incorporating binding, water/binder ratio, binder/aggregate ratio, and curing mechanisms using the Box–Behnken design approach (BBDA). A waste material, anacardium occidentale (cashew) nutshell ash, was valorised and used at 5, 10, and 15 wt.% of cement. The composites were made, cured and tested at 14–90 d. The results revealed a high precision between the experimental slump and the optimisation slump at 97% R2. In addition, a 5% increase in compressive strength was obtained compared with the target compressive strength. Besides, the correlation between the model equation obtained from this study and predictions of previous studies via BBDA yielded a strong relationship.
      Citation: Fibers
      PubDate: 2021-07-01
      DOI: 10.3390/fib9070041
      Issue No: Vol. 9, No. 7 (2021)
  • Fibers, Vol. 9, Pages 42: Application of X-Shaped CFRP Ropes for
           Structural Upgrading of Reinforced Concrete Beam–Column Joints under
           Cyclic Loading–Experimental Study

    • Authors: Emmanouil Golias, Adamantis G. Zapris, Violetta K. Kytinou, Mourhat Osman, Michail Koumtzis, Danai Siapera, Constantin E. Chalioris, Chris G. Karayannis
      First page: 42
      Abstract: The effectiveness of externally applied fiber-reinforced polymer (FRP) ropes made of carbon fibers in X-shape formation and in both sides of the joint area of reinforced concrete (RC) beam–column connections is experimentally investigated. Six full-scale exterior RC beam–column joint specimens are tested under reverse cyclic deformation. Three of them have been strengthened using carbon FRP (CFRP) ropes that have been placed diagonally in the joint as additional, near surface-mounted reinforcements against shear. Full hysteretic curves, maximum applied load capacity, damage modes, stiffness and energy dissipation values per each loading step are presented and compared. Test results indicated that joint sub assemblages with X-shaped CFRP ropes exhibited improved hysteretic behavior and ameliorated performance with respect to the reference specimens. The effectiveness and the easy-to-apply character of the presented strengthening technique is also discussed.
      Citation: Fibers
      PubDate: 2021-07-01
      DOI: 10.3390/fib9070042
      Issue No: Vol. 9, No. 7 (2021)
  • Fibers, Vol. 9, Pages 43: Flexural Performance of a New Hybrid
           Basalt-Polypropylene Fiber-Reinforced Concrete Oriented to Concrete

    • Authors: Zhiyun Deng, Xinrong Liu, Ninghui Liang, Albert de la Fuente, Haoyang Peng
      First page: 43
      Abstract: The bending performance of a basalt-polypropylene fiber-reinforced concrete (HBPFRC) was characterized by testing 24,400 × 100 × 100 mm3 prismatic specimens in a four-point bending test JSCE-SF4 configuration. The type and content of both fibers were varied in order to guarantee different target levels of post-cracking flexural performance. The results evidenced that mono-micro basalt fiber reinforced concrete (BFRC) allows the increase of the flexural strength (pre-cracking stage), while macro polypropylene fiber reinforced concrete (PPFRC) can effectively improve both bearing capacity and ductility of the composite for a wide crack width range. Compared with the plain concrete specimens, flexural toughness and equivalent flexural strength of macro PPFRC and the hybrid fiber-reinforced concrete (HFRC) increased by 3.7–7.1 times and 10–42.5%, respectively. From both technical and economic points of view, the optimal mass ratio of basalt fiber (BF) to polypropylene fiber (PPF) resulted in being 1:2, with a total content of 6 kg/m3. This HFRC is seen as a suitable material to be used in sewerage pipes where cracking control (crack formation and crack width control) is of paramount importance to guarantee the durability and functionality of the pipeline as well as the ductility of the system in case of local failures.
      Citation: Fibers
      PubDate: 2021-07-01
      DOI: 10.3390/fib9070043
      Issue No: Vol. 9, No. 7 (2021)
  • Fibers, Vol. 9, Pages 44: Micromechanical Modeling of Anisotropy and
           Strain Rate Dependence of Short-Fiber-Reinforced Thermoplastics

    • Authors: Shaokang Zhang, Johannes A. W. van Dommelen, Leon E. Govaert
      First page: 44
      Abstract: The anisotropy and strain rate dependence of the mechanical response of short-fiber-reinforced thermoplastics was studied using a straightforward micromechanical finite element analysis of representative volume elements (RVEs). RVEs are created based on the fiber orientation tensor, which quantifies the processing-induced fiber orientation distribution. The matrix is described by a strain rate-dependent constitutive model (the Eindhoven glassy polymer (EGP) model), which accurately captures the intrinsic response of amorphous polymers. The micromechanical results indicate that the influence of strain rate and that of the loading direction on the yield stress are multiplicatively decouplable, which confirms previous experimental observations. Moreover, it is demonstrated that the yield stress, to a good approximation, can be directly linked to the fiber orientation in the direction of loading. This leads to a new relation that uniquely links the rate dependence of the yield stress to the fiber orientation in loading direction.
      Citation: Fibers
      PubDate: 2021-07-02
      DOI: 10.3390/fib9070044
      Issue No: Vol. 9, No. 7 (2021)
  • Fibers, Vol. 9, Pages 45: Seismic Performance of RC Beam–Column Joints
           Designed According to Older and Modern Codes: An Attempt to Reduce
           Conventional Reinforcement Using Steel Fiber Reinforced Concrete

    • Authors: Alexander-Dimitrios Tsonos, George Kalogeropoulos, Pantelis Iakovidis, Marios-Zois Bezas, Michail Koumtzis
      First page: 45
      Abstract: An analytical and experimental investigation was conducted herein to examine the cyclic load behavior of beam–column joint subassemblages, typical of both the modern reinforced concrete (RC) structures and of the pre-1960s–1970s existing ones. Seven exterior RC beam–column joint subassemblages were constructed and subjected to earthquake-type loading. Three specimens were designed according to the requirements of the Eurocode (EC) for ductility class medium (DCM), while the other three specimens possessed poor seismic details, conforming to past building codes. The hysteresis behavior of the subassemblages was evaluated. An analytical model was used to calculate the ultimate shear capacity of the beam–column joint area, while also predicting accurately the failure mode of the specimens. It was clearly demonstrated experimentally and analytically that it is possible for excessive seismic damage of the beam–column joint region to occur when designing according to the current European building codes. In addition, the proposed analytical model was found to be very satisfactory in accurately predicting seismic behavior and in preventing the premature brittle shear failure of the joints. The seventh subassemblage, constructed with steel fiber RC and significantly less transverse reinforcement than that required according to the EC, exhibited satisfactory ductile seismic performance, demonstrating the effectiveness of the proposed design solution.
      Citation: Fibers
      PubDate: 2021-07-05
      DOI: 10.3390/fib9070045
      Issue No: Vol. 9, No. 7 (2021)
  • Fibers, Vol. 9, Pages 46: ANN-Based Model for the Prediction of the Bond
           Strength between FRP and Concrete

    • Authors: Alessio Cascardi, Francesco Micelli
      First page: 46
      Abstract: In the last decades, the uses of fiber reinforced polymer (FRP) composites in the structural strengthening of reinforced concrete (RC) structures have become the state of the art, providing a valid alternative to the traditional use of steel plates. These relatively new materials present, in fact, great advantages, including high corrosion resistance in aggressive environments, low specific weight, high strength-to-mass-density ratio, magnetic and electric neutrality, low axial coefficient of thermal expansion and sustainable costs of installation. In flexural and shear strengthening of RC members, the effectiveness of the epoxy bonded FRP strongly depends on the adhesion forces exchanged with the concrete substrate. When the flexural moment is present, the FRP strengthening is activated through the stress transfer on the tension side, which is guaranteed by the contact beam region to which the adhesive is bonded to the beam itself. Hence, the determination of the maximum forces that cause debonding of the FRP-plate becomes crucial for a proper design. Over the years, many different analytical models have been provided in the scientific literature. Most of them are based on the calibration of the narrow experimental database. Now, hundreds of experimental results are available. The main goal of the current study is to present and discuss an alternative theoretical formulation for predicting the debonding force in an FRP-plate, epoxy-bonded to the concrete substrate by using an artificial neural networks (ANNs) approach. For this purpose, an extensive study of the state of the art, reporting the results of single lap shear tests, is also reported and discussed. The robustness of the proposed analytical model was validated by performing a parametric analysis and a comparison with other existing models and international design codes, as shown herein.
      Citation: Fibers
      PubDate: 2021-07-06
      DOI: 10.3390/fib9070046
      Issue No: Vol. 9, No. 7 (2021)
  • Fibers, Vol. 9, Pages 34: Depolarization of Light in Optical Fibers:
           Effects of Diffraction and Spin-Orbit Interaction

    • Authors: Nikolai I. Petrov
      First page: 34
      Abstract: Polarization is measured very often to study the interaction of light and matter, so the description of the polarization of light beams is of both practical and fundamental interest. This review discusses the polarization properties of structured light in multimode graded-index optical fibers, with an emphasis on the recent advances in the area of spin-orbit interactions. The basic physical principles and properties of twisted light propagating in a graded index fiber are described: rotation of the polarization plane, Laguerre–Gauss vector beams with polarization-orbital angular momentum entanglement, splitting of degenerate modes due to spin-orbit interaction, depolarization of light beams, Berry phase and 2D and 3D degrees of polarizations, etc. Special attention is paid to analytical methods for solving the Maxwell equations of a three-component field using perturbation analysis and quantum mechanical approaches. Vector and tensor polarization degrees for the description of strongly focused light beams and their geometrical interpretation are also discussed.
      Citation: Fibers
      PubDate: 2021-06-01
      DOI: 10.3390/fib9060034
      Issue No: Vol. 9, No. 6 (2021)
  • Fibers, Vol. 9, Pages 35: Application of Capillary Polypropylene Membranes
           for Microfiltration of Oily Wastewaters: Experiments and Modeling

    • Authors: Wirginia Tomczak, Marek Gryta
      First page: 35
      Abstract: Oily wastewaters are considered as one of the most dangerous types of environmental pollution. In the present study, the microfiltration (MF) process of model emulsions and real oily wastewaters was investigated. For this purpose, capillary polypropylene (PP) membranes were used. The experiments were conducted under transmembrane pressure (TMP) and feed flow rate (VF) equal to 0.05 MPa and 0.5 m/s, respectively. It was found that the used membranes ensured a high-quality permeate with turbidity equal to about 0.4 NTU and oil concentration of 7–15 mg/L. As expected, a significant decrease in the MF process performance was noted. However, it is shown that the initial decline of permeate flux could be slightly increased by increasing the feed temperature from 25 °C to 50 °C. Furthermore, Hermia’s models were used to interpret the fouling phenomenon occurring in studied experiments. It was determined that cake formation was the dominant fouling mechanism during filtration of both synthetic and real feeds. Through detailed studies, we present different efficient methods of membrane cleaning. Results, so far, are very encouraging and may have an important impact on increasing the use of polypropylene MF membranes in oily wastewater treatments.
      Citation: Fibers
      PubDate: 2021-06-02
      DOI: 10.3390/fib9060035
      Issue No: Vol. 9, No. 6 (2021)
  • Fibers, Vol. 9, Pages 36: Properties of Scalable Chirped-Pulse Optical
           Comb in Erbium-Doped Ultrafast All-Fiber Ring Laser

    • Authors: Ilya O. Orekhov, Dmitriy A. Dvoretskiy, Stanislav G. Sazonkin, Yan Z. Ososkov, Anton O. Chernutsky, Aleksander Y. Fedorenko, Lev K. Denisov, Valeriy E. Karasik
      First page: 36
      Abstract: We report on a scalable chirped-pulse Er-doped all-fiber laser, passively mode-locked by single-wall carbon nitride nanotubes. The average output power is ~15 mW, which corresponds to a peak power of ~77 W, and pulse energy of ~1.9 nJ and was achieved using a single amplification stage. We observed chirped-pulse generation with a duration of ~24.6 ps at a relatively low repetition rate of ~7.9 MHz, with a signal-to-noise ratio of ~69 dB. To characterize the short-term stability of the obtained regime, we have measured the relative intensity noise of the laser, which is <−107 dBc/Hz in the range of 3 Hz–1000 kHz. It should be noted that the standard deviation of root mean square of average power does not exceed a magnitude of 0.9% for 3 h of measurement.
      Citation: Fibers
      PubDate: 2021-06-02
      DOI: 10.3390/fib9060036
      Issue No: Vol. 9, No. 6 (2021)
  • Fibers, Vol. 9, Pages 37: Zeolite Composite Nanofiber Mesh for Indoxyl
           Sulfate Adsorption toward Wearable Blood Purification Devices

    • Authors: Makoto Sasaki, Yihua Liu, Mitsuhiro Ebara
      First page: 37
      Abstract: A nanofiber mesh was prepared for the adsorption of indoxyl sulfate (IS), a toxin associated with chronic kidney disease. Removing IS is highly demanded for efficient blood purification. The objective of this study is to develop a zeolite composite nanofiber mesh to remove IS efficiently. Eight zeolites with different properties were used for IS adsorption, where a zeolite with a pore size of 7 Å, H+ cations, and a silica to aluminum ratio of 240 mol/mol exhibited the highest adsorption capacity. This was primarily attributed to its suitable silica to aluminum ratio. The zeolites were incorporated in biocompatible poly (ethylene-co-vinyl alcohol) (EVOH) nanofibers, and a zeolite composite nanofiber mesh was successfully fabricated via electrospinning. The nanofiber mesh exhibited an IS adsorption capacity of 107 μg/g, while the adsorption capacity by zeolite increased from 208 μg/g in powder form to 386 μg/g when dispersed in the mesh. This also led to an increase in cell viability from 86% to 96%. These results demonstrated that this zeolite composite nanofiber mesh can be safely and effectively applied in wearable blood purification devices.
      Citation: Fibers
      PubDate: 2021-06-03
      DOI: 10.3390/fib9060037
      Issue No: Vol. 9, No. 6 (2021)
  • Fibers, Vol. 9, Pages 38: Low-Cost Electrodeposition of Size-Tunable
           Single-Crystal ZnO Nanorods

    • Authors: Elias Sakellis, Antonis Markopoulos, Christos Tzouvelekis, Manolis Chatzigeorgiou, Anastasios Travlos, Nikos Boukos
      First page: 38
      Abstract: In this paper we report a low cost, simple, electrochemical method for large-area growth of single crystal ZnO nanorods. The method utilizes a metallic zinc foil as the source of the necessary zinc ions for ZnO growth on indium-doped tin oxide (ITO) glass slides. The method is thoroughly discussed and investigated varying all the parameters involved. The resulting ZnO nanorods are highly oriented along c-axis and densely packed, while their length and diameter can be tuned by varying the growth parameters. Two different types of seed layers on the ITO glass slides are tested. A seed layer made by spin coating of ZnO nanoparticles results in a twofold increase of the ZnO nanorod surface density as compared with a ZnO thin film seed layer by physical vapor deposition. Additionally, the effect of oxygen supply during electrodeposition was investigated as a crucial regulatory parameter not only for the geometrical and topological characteristics of the ZnO nano-arrays but for their physical properties as well.
      Citation: Fibers
      PubDate: 2021-06-07
      DOI: 10.3390/fib9060038
      Issue No: Vol. 9, No. 6 (2021)
  • Fibers, Vol. 9, Pages 39: Development of a Robot-Based Multi-Directional
           Dynamic Fiber Winding Process for Additive Manufacturing Using Shotcrete
           3D Printing

    • Authors: Norman Hack, Mohammad Bahar, Christian Hühne, William Lopez, Stefan Gantner, Noor Khader, Tom Rothe
      First page: 39
      Abstract: The research described in this paper is dedicated to the use of continuous fibers as reinforcement for additive manufacturing, particularly using Shotcrete. Composites and in particular fiber reinforced polymers (FRP) are increasingly present in concrete reinforcement. Their corrosion resistance, high tensile strength, low weight, and high flexibility offer an interesting alternative to conventional steel reinforcement, especially with respect to their use in Concrete 3D Printing. This paper presents an initial development of a dynamic robot-based manufacturing process for FRP concrete reinforcement as an innovative way to increase shape freedom and efficiency in concrete construction. The focus here is on prefabricated fiber reinforcement, which is concreted in a subsequent additive process to produce load-bearing components. After the presentation of the fabrication concept for the integration of FRP reinforcement and the state of the art, a requirements analysis regarding the mechanical bonding behavior in concrete is carried out. This is followed by a description of the development of a dynamic fiber winding process and its integration into an automated production system for individualized fiber reinforcement. Next, initial tests for the automated application of concrete by means of Shotcrete 3D Printing are carried out. In addition, an outlook describes further technical development steps and provides an outline of advanced manufacturing concepts for additive concrete manufacturing with integrated fiber reinforcement.
      Citation: Fibers
      PubDate: 2021-06-08
      DOI: 10.3390/fib9060039
      Issue No: Vol. 9, No. 6 (2021)
  • Fibers, Vol. 9, Pages 27: Twisted Silica Microstructured Optical Fiber
           with Equiangular Spiral Six-Ray Geometry

    • Authors: Anton V. Bourdine, Alexey Yu. Barashkin, Vladimir A. Burdin, Michael V. Dashkov, Vladimir V. Demidov, Konstantin V. Dukelskii, Alexander S. Evtushenko, Yaseera Ismail, Alexander V. Khokhlov, Artem A. Kuznetsov, Alexandra S. Matrosova, Oleg G. Morozov, Grigori A. Pchelkin, Francesco Petruccione, Airat Zh. Sakhabutdinov, Ghanshyam Singh, Egishe V. Ter-Nersesyants, Manish Tiwari, Elena S. Zaitseva, Vijay Janyani, Juan Yin
      First page: 27
      Abstract: This work presents fabricated silica microstructured optical fiber with special equiangular spiral six-ray geometry, an outer diameter of 125 µm (that corresponds to conventional commercially available telecommunication optical fibers of ratified ITU-T recommendations), and induced chirality with twisting of 200 revolutions per minute (or e.g., under a drawing speed of 3 m per minute, 66 revolutions per 1 m). We discuss the fabrication of twisted microstructured optical fibers. Some results of tests, performed with pilot samples of designed and manufactured stellar chiral silica microstructured optical fiber, including basic transmission parameters, as well as measurements of near-field laser beam profile and spectral and pulse responses, are represented.
      Citation: Fibers
      PubDate: 2021-05-02
      DOI: 10.3390/fib9050027
      Issue No: Vol. 9, No. 5 (2021)
  • Fibers, Vol. 9, Pages 28: Formation of Polysulfone Hollow Fiber Membranes
           Using the Systems with Lower Critical Solution Temperature

    • Authors: Tatiana V. Plisko, Alexandr V. Bildyukevich, Liang Zhao, Weiqing Huang, Vladimir V. Volkov, Zuohua Huang
      First page: 28
      Abstract: This study deals with the investigation of the phase state of the polymer systems from polysulfone (PSF) with the addition of polyethylene glycol (PEG-400, Mn = 400 g·mol−1) and polyvinylpyrrolidone (PVP K-30, Mn = 40,000 g·mol−1) in N,N-dimethylacetamide (DMA), which feature lower critical solution temperatures (LCSTs). A fragment of the phase state diagram of the system PSF —PEG-400—PVP K-30—DMA was experimentally constructed in the following range of component concentrations: PSF 20–24 wt.%, PEG-400—35–38 wt.% and PVP—0–8 wt.%. It has been established that PVP addition substantially reduces the phase separation temperature down to 50–60 °C. Based on the obtained phase diagrams, a method for preparation of highly permeable hollow fiber membranes from PSF, which involves the processing of the dope solution at a temperature close to the LCST and the temperature of the bore fluid above the LCST, was proposed. Hollow fiber membranes with pure water flux of 1200 L·m−2·h−1 and a sponge-like macrovoid-free structure were obtained via LCST-thermally induced phase separation by free fall spinning technique.
      Citation: Fibers
      PubDate: 2021-05-02
      DOI: 10.3390/fib9050028
      Issue No: Vol. 9, No. 5 (2021)
  • Fibers, Vol. 9, Pages 29: Seismic Performance Enhancement of RC Columns
           Using Thin High-Strength RC Jackets and CFRP Jackets

    • Authors: George Kalogeropoulos, Alexander-Dimitrios Tsonos
      First page: 29
      Abstract: The existing non-ductile RC structures built prior to the 1960s–1970s were mainly conceived to carry only vertical loads. As a result, the columns of these structures demonstrate poor overall hysteresis behavior during strong earthquakes, dominated by brittle shear or/and premature excessive slipping of the inadequately lap-spliced reinforcement. In the present study, the effectiveness of two different strengthening systems (including either the wrapping of the columns by carbon-fiber-reinforced polymer textile or the use of thin high-strength reinforced concrete jackets), was experimentally and analytically investigated. The main variables examined were the strengthening material, the length of the lap splices and the amount of confinement provided by the jackets. Three cantilever column specimens were constructed without incorporating modern design code requirements for preserving seismic safety and structural integrity. Subsequently, the specimens were strengthened and subjected to earthquake-type loading. Their hysteresis performances were compared, while also evaluated with respect to the response of two similar original specimens and the behavior of a control one with continuous reinforcement, tested in a previous study. The predictions of the proposed analytical formulation for the hysteresis behavior of the strengthened specimens were satisfactorily verified by the experimental results.
      Citation: Fibers
      PubDate: 2021-05-03
      DOI: 10.3390/fib9050029
      Issue No: Vol. 9, No. 5 (2021)
  • Fibers, Vol. 9, Pages 30: Rammed Earth with Straw Fibers and Earth Mortar:
           Mix Design and Mechanical Characteristics Determination

    • Authors: Maria Francesca Sabbà, Mariateresa Tesoro, Cecilia Falcicchio, Dora Foti
      First page: 30
      Abstract: Raw earth is one of the oldest building materials, which is suitable for various uses: from the construction of load-bearing walls to use for plasters and finishes. The presence of straw fibers can give different behavior to this material. The present paper illustrates preliminary sensory and qualitative analyses, and subsequent laboratory tests that allow the characterization of the raw earth material with straw fibers for rammed earth constructions through mechanized compaction and the identification of a compatible earth mortar. The raw material considered in this study is mainly clayey; for this reason, a mix design usable with the pisé (or clay) technique has been developed. Cylindrical samples have been made through a press and subject to unconfined compression and indirect tensile tests. The results of the tests showed consistent tensile and compressive strength values in the context of earth materials. At the same time, a study for the realization of a mortar with the same base soil was carried out considering four mixtures, in order to investigate the best compromise between workability, shrinkage and compressive strengths. The purpose of the study was to investigate the mechanical characteristics of the local material through preliminary and laboratory tests, to classify it according to the Unified Soil Classification System (USCS) and to verify its suitability for a possible use in the construction field.
      Citation: Fibers
      PubDate: 2021-05-04
      DOI: 10.3390/fib9050030
      Issue No: Vol. 9, No. 5 (2021)
  • Fibers, Vol. 9, Pages 31: Density Profile Analysis of Laminated Beech
           Veneer Lumber (BauBuche)

    • Authors: Nick Engehausen, Jan T. Benthien, Martin Nopens, Jörg B. Ressel
      First page: 31
      Abstract: An irreversible swelling was detected in laminated beech veneer lumber within the initial moistening. Supported by the facts that the lay-up of the glued veneers is exposed to high pressure during hot pressing, and that the density of the finished material exceeds that of solid beech, it was hypothesised that the wood substance is compressed. Laboratory X-ray density profile scans were performed to check this and to identify the part of the material cross section in which the densification has taken place. The higher density was found to be located in the area of the adhesive joints, uniformly over the cross section, while the density in the middle of the veneers corresponds to that of solid beech wood.
      Citation: Fibers
      PubDate: 2021-05-05
      DOI: 10.3390/fib9050031
      Issue No: Vol. 9, No. 5 (2021)
  • Fibers, Vol. 9, Pages 32: Statistical Analysis of Mechanical Stressing in
           Short Fiber Reinforced Composites by Means of Statistical and
           Representative Volume Elements

    • Authors: Kevin Breuer, Axel Spickenheuer, Markus Stommel
      First page: 32
      Abstract: Analyzing representative volume elements with the finite element method is one method to calculate the local stress at the microscale of short fiber reinforced plastics. It can be shown with Monte-Carlo simulations that the stress distribution depends on the local arrangement of the fibers and is therefore unique for each fiber constellation. In this contribution the stress distribution and the effective composite properties are examined as a function of the considered volume of the representative volume elements. Moreover, the influence of locally varying fiber volume fraction is examined, using statistical volume elements. The results show that the average stress probability distribution is independent of the number of fibers and independent of local fluctuation of the fiber volume fraction. Furthermore, it is derived from the stress distributions that the statistical deviation of the effective composite properties should not be neglected in the case of injection molded components. A finite element analysis indicates that the macroscopic stresses and strains on component level are significantly influenced by local, statistical fluctuation of the composite properties.
      Citation: Fibers
      PubDate: 2021-05-06
      DOI: 10.3390/fib9050032
      Issue No: Vol. 9, No. 5 (2021)
  • Fibers, Vol. 9, Pages 33: Electrochemical Deposition of SiO2-Coatings on a
           Carbon Fiber

    • Authors: Galyshev, Postnova
      First page: 33
      Abstract: Research on carbon fiber oxide coatings is primarily focused on metal matrix composites. Such coatings act as a diffusion barrier between a matrix and a fiber and, in addition, they can be weak boundaries that significantly increase the mechanical properties of metal matrix composites. A simple and economical method of coating deposition is the sol–gel method. However, it does not allow for control of the thickness of the carbon fiber coating. To eliminate this limitation, a combined method is used that includes sol–gel technology and electrochemical deposition. The paper presents the results of studies on the production of SiO2 coatings on carbon fibers by the above method. The effect of current density, deposition time, salt concentration, pH of the reaction medium, TEOS/H2O molar ratio, and alcohol concentration in the reaction medium on the structure and thickness of the coatings was studied.
      Citation: Fibers
      PubDate: 2021-05-07
      DOI: 10.3390/fib9050033
      Issue No: Vol. 9, No. 5 (2021)
  • Fibers, Vol. 9, Pages 21: Mid-Infrared Ultra-Short Pulse Generation in a
           Gas-Filled Hollow-Core Photonic Crystal Fiber Pumped by Two-Color Pulses

    • Authors: Coralie Fourcade-Dutin, Olivia Zurita-Miranda, Patrick Mounaix, Damien Bigourd
      First page: 21
      Abstract: We show numerically that ultra-short pulses can be generated in the mid-infrared when a gas filled hollow-core fiber is pumped by a fundamental pulse and its second harmonic. The generation process originates from a cascaded nonlinear phenomenon starting from a spectral broadening of the two pulses followed by an induced phase-matched four wave-mixing lying in the mid-infrared combined with a dispersive wave. By selecting this mid-infrared band with a spectral filter, we demonstrate the generation of ultra-short 60 fs pulses at a 3–4 µm band and a pulse duration of 20 fs can be reached with an additional phase compensator.
      Citation: Fibers
      PubDate: 2021-04-01
      DOI: 10.3390/fib9040021
      Issue No: Vol. 9, No. 4 (2021)
  • Fibers, Vol. 9, Pages 22: Closed-Form Solution Procedure for Simulating
           Debonding in FRP Strips Glued to a Generic Substrate Material

    • Authors: Enzo Martinelli
      First page: 22
      Abstract: The present paper proposes a useful closed-form solution for a wide class of mechanical problems, among which one of the most relevant and debated is the deboning process of Fiber-Reinforced Polymer (FRP) strips glued to generic materials and possibly intended as a mode-II fracture process. Specifically, after outlining well-known equations, a novel piecewise analytical formulation based on a cascading solution process is proposed with the aim of keeping the mathematical expressions of the relevant mechanical quantities as simple as possible. Although other analytical solutions and numerical procedures are already available in the literature, the present one is capable of handling the softening or snap-back response deriving from the full-range simulation of the depending process with no need for complex numerical techniques. This is obtained by considering the slip at the free end of the strip as the main displacement control parameter. After some comparisons between the proposed closed-form solution and experimental results available in the literature, some mechanical considerations are highlighted by elaborating on the results of a parametric study considering the variation of the main geometric and mechanical quantities. The numerical code implemented as part of the present study is available to readers in Open Access.
      Citation: Fibers
      PubDate: 2021-04-01
      DOI: 10.3390/fib9040022
      Issue No: Vol. 9, No. 4 (2021)
  • Fibers, Vol. 9, Pages 23: An Application Review of Fiber-Reinforced
           Geopolymer Composite

    • Authors: Sneha Samal, Ignazio Blanco
      First page: 23
      Abstract: Fiber-reinforced geopolymer composites (FRGCs) were considered in terms of application in various areas, and a review is presented in this article. FRGCs are emerging as environmentally friendly materials, replacing cement in the construction industry. An alternative inorganic binder such as a geopolymer matrix promotes environmental awareness on releasing less CO2. The inorganic matrix geopolymer is considered a greener cement for FRGCs. Various types of fiber reinforcements and their role toward the improvement of tensile, flexural, impact strength, fracture toughness, and energy absorption in overall mechanical performance in FRGCs were discussed. FRGCs and their properties in mechanical response, with correlation toward microstructure evolution at room and elevated temperatures, were also discussed. Simultaneously, the durability and impact strength of FRGCs and damage area as a function of the energy absorption were presented with 3D reconstruction images. Moreover, 3D images will cover the internal volume of the FRGCs with internal porosity and fiber orientation. Hybrid fiber reinforcement adds an extra step for the application of geopolymer composites for structural applications.
      Citation: Fibers
      PubDate: 2021-04-06
      DOI: 10.3390/fib9040023
      Issue No: Vol. 9, No. 4 (2021)
  • Fibers, Vol. 9, Pages 24: Novel Insight into the Intricate Shape of Flax
           Fibre Lumen

    • Authors: Emmanuelle Richely, Sylvie Durand, Alessia Melelli, Alexander Kao, Anthony Magueresse, Hom Dhakal, Tatyana Gorshkova, Franck Callebert, Alain Bourmaud, Johnny Beaugrand, Sofiane Guessasma
      First page: 24
      Abstract: Plant fibres and especially flax can be distinguished from most synthetic fibres by their intricate shape and intrinsic porosity called lumen, which is usually assumed to be tubular. However, the real shape appears more complex and thus might induce stress concentrations influencing the fibre performance. This study proposes a novel representation of flax fibre lumen and its variations along the fibre, an interpretation of its origin and effect on flax fibre tensile properties. This investigation was conducted at the crossroads of complementary characterization techniques: optical and scanning electron microscopy (SEM), high-resolution X-ray microtomography (µCT) and mechanical tests at the cell-wall and fibre scale by atomic force microscopy (AFM) in Peak-Force Quantitative Nano-Mechanical property mapping (PF-QNM) mode and micromechanical tensile testing. Converging results highlight the difficulty of drawing a single geometric reference for the lumen. AFM and optical microscopy depict central cavities of different sizes and shapes. Porosity contents, varying from 0.4 to 7.2%, are estimated by high-resolution µCT. Furthermore, variations of lumen size are reported along the fibres. This intricate lumen shape might originate from the cell wall thickening and cell death but particular attention should also be paid to the effects of post mortem processes such as drying, retting and mechanical extraction of the fibre as well as sample preparation. Finally, SEM observation following tensile testing demonstrates the combined effect of geometrical inhomogeneities such as defects and intricate lumen porosity to drive the failure of the fibre.
      Citation: Fibers
      PubDate: 2021-04-06
      DOI: 10.3390/fib9040024
      Issue No: Vol. 9, No. 4 (2021)
  • Fibers, Vol. 9, Pages 25: Cellulose Microfibril and Micronized Rubber
           Modified Asphalt Binder

    • Authors: Ang Li, Abdu A. Danladi, Rahul Vallabh, Mohammed K. Yakubu, Umar Ishiaku, Thomas Theyson, Abdel-Fattah M. Seyam
      First page: 25
      Abstract: Cellulose microfibrils (CMFs) and micronized rubber powder (MRP) can be derived from low or negative-cost agricultural/industrial waste streams and offer environment-friendly and cost-effective pathways to develop engineering products. This study investigated the efficacy of adding these micromodifiers on the performance characteristics of asphalt binders. In this work, samples were produced using a mixture of slow-setting anionic asphalt emulsion with various combinations of MRP (at 0, 2 and 10 wt %) and four types of CMFs (hydrophobic and hydrophilic with crystalline ratios of 86% and 95%) at 0, 2 and 5 wt %. The performance of modified asphalt samples was assessed by penetration depth (PD), softening point (SP), and penetration index (PI). Linear regression analysis showed that adding CMFs and/or MRP reduced PD and increased SP values. The type of CMFs significantly affected the performance, which becomes more distinct with the increased weight content of CMFs. While hydrophilic CMFs caused increases in SP and PI values, no clear trend was seen to determine the effect of CMF crystallinity. It was also discovered that the combined addition of CMF and MRP achieved similar PI values at lower total weight content compared to using MRP alone.
      Citation: Fibers
      PubDate: 2021-04-07
      DOI: 10.3390/fib9040025
      Issue No: Vol. 9, No. 4 (2021)
  • Fibers, Vol. 9, Pages 26: Reinforcement of Flexural Members with Basalt
           Fiber Mortar

    • Authors: Dmitry Kurlapov, Sergey Klyuev, Yury Biryukov, Nikolai Vatin, Dmitry Biryukov, Roman Fediuk, Yuriy Vasilev
      First page: 26
      Abstract: Reconstruction of buildings and structures is becoming one of the main directions in the field of construction, and the design and production of works during reconstruction are significantly different from the ones of new buildings and structures. After carrying out a number of studies on the inspection of the technical condition of buildings in order to determine the effect of defects on the bearing capacity, the criteria for assessing the state of floor slab structures were identified. Conclusions on the state and further work of elements of reinforced concrete structures are considered. The authors achieve the aim of reinforcing flexural elements of reinforced concrete structures with fiber-reinforced mortar, which is especially important for floor elements with increased operational requirements. A technique for constructing a reinforcement layer using fiber-reinforced mortar from coarse basalt fiber has been developed. The parameters of basalt fiber in the reinforcement layer are substantiated. A method for solving problems of the operation of multilayer coatings under the influence of operational loads is used, in which the model prerequisites for describing the operation of layers are simplified, where the bearing layers are represented by classical Kirchhoff-Love plates. When solving problems, the maximum possible number of design features of flexural members is taken into account, in combination with appropriate experimental studies, the method allows us to consider all the variety of structures for reinforcing coatings and meet the needs of their practical application.
      Citation: Fibers
      PubDate: 2021-04-16
      DOI: 10.3390/fib9040026
      Issue No: Vol. 9, No. 4 (2021)
  • Fibers, Vol. 9, Pages 14: Combined Functionalization of Carbon Nanotubes
           (CNT) Fibers with H2SO4/HNO3 and Ca(OH)2 for Addition in Cementitious

    • Authors: Eduardo Batiston, Paulo Ricardo de Matos, Philippe Jean Paul Gleize, Roman Fediuk, Sergey Klyuev, Nikolai Vatin, Maria Karelina
      First page: 14
      Abstract: Acid treatment is commonly used to improve the dispersion of carbon nanotubes (CNT) in a cementitious matrix, but it causes undesired delay on cement hydration kinetics. This work reports a combined CNT functionalization method with H2SO4/HNO3 and Ca(OH)2 for addition in a cementitious matrix. Results showed that the Ca(OH)2 exposure neutralized the active sites generated by acid exposure, compensating the delay in hydration. As a result, CNT exposed to H2SO4/HNO3 for 9 h and further Ca(OH)2 treatment led to equivalent hydration kinetics than un-treated CNT did with improved stability.
      Citation: Fibers
      PubDate: 2021-03-01
      DOI: 10.3390/fib9030014
      Issue No: Vol. 9, No. 3 (2021)
  • Fibers, Vol. 9, Pages 15: Fabrication and Characterization of Er/Yb
           Co-Doped Fluorophosphosilicate Glass Core Optical Fibers

    • Authors: Denis S. Lipatov, Alexey S. Lobanov, Alexey N. Guryanov, Andrey A. Umnikov, Alexey N. Abramov, Maxim M. Khudyakov, Mikhail E. Likhachev, Oleg G. Morozov
      First page: 15
      Abstract: The technical process of the synthesis of a fluorophosphosilicate (FPS) glass core was thoroughly investigated for the first time utilizing a modified chemical vapor deposition (MCVD) all-gas-phase fabrication method. It was discovered that the limiting doping level of the silica glass simultaneously co-doped with phosphorus (P) and fluorine (F) was found to be confined by the formation of POF3 gas. The dopants content was achieved as high as 4.7 at% of P and 1.1 at% of F in a glass core, respectively. A developed “in-house” manufacturing method makes it possible to fabricate a large mode area (LMA) purely single-mode Er–Yb co-doped optical fibers with a core diameter of 20 μm and with a lasing efficiency comparable to commercially available LMA Er–Yb optical fibers.
      Citation: Fibers
      PubDate: 2021-03-01
      DOI: 10.3390/fib9030015
      Issue No: Vol. 9, No. 3 (2021)
  • Fibers, Vol. 9, Pages 16: Mechanical Performance of Fiber Reinforced
           Cement Composites Including Fully-Recycled Plastic Fibers

    • Authors: Cesare Signorini, Valentina Volpini
      First page: 16
      Abstract: The use of virgin and recycled plastic macro fibers as reinforcing elements in construction materials has recently gained increasing attention from researchers. Specifically, recycled fibers have become more attractive owing to their large-scale availability, negligible cost, and low environmental footprint. In this work, we investigate the benefits related to the use of fully-recycled synthetic fibers as dispersed reinforcement in Fiber Reinforced Cement Composites (FRCCs). In light of the reference performance of FRCCs including virgin polypropylene (PP) fibers only, the mechanical response of composites reinforced with polyolefin filaments treated with a sol-gel silica coating and polyethylene terephthalate (PET)/polyethylene (PE) cylindrical draw-wire fibers is here assessed through three-point bending tests. Remarkably, recycled polyolefins lead to a notable enhancement in terms of peak strength and post-crack energy dissipation capability. This improvement is ascribed to both the flattened shape of fibers and the surface coating, which turns out to be very effective at strengthening the fiber-to-matrix bond. On the other hand, PET/PE fibrous reinforcement generally leads to a lower toughness, if compared to the virgin fibers. However, no reduction in terms of peak stress is evidenced. Balancing the significance of mechanical performance and environmental sustainability in the framework of a circular economy approach, both fully-recycled fibers at hand can be regarded as promising candidates for innovative structural applications.
      Citation: Fibers
      PubDate: 2021-03-01
      DOI: 10.3390/fib9030016
      Issue No: Vol. 9, No. 3 (2021)
  • Fibers, Vol. 9, Pages 17: Online Pre-Treatment of Thermomechanical Pulp
           with Emulsified Maleated Polypropylene for Processing of Extruded
           Thermoplastic Composites

    • Authors: Arne Schirp, Claudia Schirp
      First page: 17
      Abstract: The effectiveness of maleated polypropylene (MAPP) in emulsified form for the pre-treatment of thermo-mechanical pulp (TMP) before extrusion with polypropylene fibres was evaluated. MAPP in pellet form, which was applied during the compounding step, served as a benchmark. In addition, commercial softwood flour was included as a reference. The influence of the temperature during the defibration process and the presence or absence of the coupling agent on composite performance were evaluated. Composites were processed with a high wood content of 70 wt.%, which is common for extruded profiles. It was found that TMP based on Robinia (Robinia pseudoacacia L.) conferred higher strength properties to the composites compared to TMP based on Scots pine (Pinus sylvestris L.), which was attributed to the higher length/diameter ratio of fibres in Robinia. However, under the conditions of this study, strength properties were superior and water uptake and swelling were reduced when wood flour was used instead of TMP. On the other hand, in many formulations, larger improvements in flexural and tensile strength due to MAPP were found for the TMP-based composites compared to the wood flour-based composites. This could be due to the larger surface/volume ratio for TMP compared to wood flour and more efficient stress transfer from fibres to the matrix. Results from X-ray photoelectron spectroscopy (XPS) showed that TMP surfaces were more hydrophobic than wood flour due to coverage with lignin, which reduced the effectiveness of MAPP. Esterification between the emulsified MAPP and fibre surfaces was determined using Fourier-Transform Infrared (FTIR) spectroscopy, but some non-activated maleic anhydride remained. Under the conditions of this study, MAPP added during compounding provided better performance compared to MAPP which included a non-ionic emulsifier and which was added during the refining process. Lower temperature (150 °C) during defibration was shown to be beneficial for the strength properties of composites compared to high temperature (180 °C) when MAPP was included in the formulations.
      Citation: Fibers
      PubDate: 2021-03-03
      DOI: 10.3390/fib9030017
      Issue No: Vol. 9, No. 3 (2021)
  • Fibers, Vol. 9, Pages 18: Synthesis and Transformation of Hollow Rutile
           Titania Wires by Single Spinneret Electrospinning with Sol-Gel Chemistry

    • Authors: Kang, Evans
      First page: 18
      Abstract: The work described below was carried out to understand how to control the morphology of nanostructured titania calcined from electrospun nanofibers. This is the first report of hollow rutile nanofibers synthesized from electrospun nanofibers with short calcination time. Titanium isopropoxide was incorporated into the nanofibers as the titania precursor. The electrospinning technique was used to fabricate ceramic/polymer hybrid nanofibers. The electrospun nanofibers were then calcined to produce rutile titania nanofibers with different morphologies (hollow or solid nanofibers), which were characterized by SEM and TEM. The initial concentration of ceramic precursor and the calcination time were shown to control the morphology of the nanofiber. The hollow morphology was only obtained with a concentration of the precursor within a certain level and with short calcination times. The heat treatment profile contributed to particle growth. At longer times, the particle growth led to the closure of the hollow core and all the nanofibers resembled strings of solid particles. A formation mechanism for the hollow nanofibers is also proposed.
      Citation: Fibers
      PubDate: 2021-03-06
      DOI: 10.3390/fib9030018
      Issue No: Vol. 9, No. 3 (2021)
  • Fibers, Vol. 9, Pages 19: Synthesis of Curcumin Loaded Smart pH-Responsive
           Stealth Liposome as a Novel Nanocarrier for Cancer Treatment

    • Authors: Ali Zarrabi, Atefeh Zarepour, Arezoo Khosravi, Zahra Alimohammadi, Vijay Kumar Thakur
      First page: 19
      Abstract: The innovation of drug delivery vehicles with controlled properties for cancer therapy is the aim of most pharmaceutical research. This study aims to fabricate a new type of smart biocompatible stealth-nanoliposome to deliver curcumin for cancer treatment. Herein, four different types of liposomes (with/without pH-responsive polymeric coating) were synthesized via the Mozafari method and then characterized with several tests, including dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), Zeta potential, and field emission scanning electron microscopes (FE-S EM). The loading and release profile of curcumin were evaluated in two pH of 7.4 and 6.6. Finally, the MTT assay was used to assess the cytotoxicity of the samples. FE-SEM results revealed a mean size of about 40 and 50 nm for smart stealth-liposome and liposome, respectively. The results of drug entrapment revealed that non-coated liposome had about 74% entrapment efficiency, while it was about 84% for PEGylated liposomes. Furthermore, the drug released pattern of the nanocarriers showed more controllable release in stealth-liposome in comparison to non-coated one. The results of the cytotoxicity test demonstrated the toxicity of drug-loaded carriers on cancer cells. Based on the results of this study, the as-prepared smart stealth pH-responsive nanoliposome could be considered as a potential candidate for cancer therapy.
      Citation: Fibers
      PubDate: 2021-03-08
      DOI: 10.3390/fib9030019
      Issue No: Vol. 9, No. 3 (2021)
  • Fibers, Vol. 9, Pages 20: Addendum: Sultana, J., et al. Terahertz Hollow
           Core Antiresonant Fiber with Metamaterial Cladding. Fibers 2020, 8, 14

    • Authors: Jakeya Sultana, Md. Saiful Islam, Cristiano M. B. Cordeiro, Alex Dinovitser, Mayank Kaushik, Brian W.-H. Ng, Derek Abbott
      First page: 20
      Abstract: This paper [...]
      Citation: Fibers
      PubDate: 2021-03-09
      DOI: 10.3390/fib9030020
      Issue No: Vol. 9, No. 3 (2021)
  • Fibers, Vol. 9, Pages 8: Prediction of Short Fiber Composite Properties by
           an Artificial Neural Network Trained on an RVE Database

    • Authors: Kevin Breuer, Markus Stommel
      First page: 8
      Abstract: In this study, an artificial neural network is designed and trained to predict the elastic properties of short fiber reinforced plastics. The results of finite element simulations of three-dimensional representative volume elements are used as a data basis for the neural network. The fiber volume fraction, fiber length, matrix-phase properties, and fiber orientation are varied so that the neural network can be used within a very wide range of parameters. A comparison of the predictions of the neural network with additional finite element simulations shows that the stiffnesses of short fiber reinforced plastics can be predicted very well by the neural network. The average prediction accuracy is equal or better than by a two-step homogenization using the classical method of Mori and Tanaka. Moreover, it is shown that the training of the neural network on an extended data set works well and that particularly calculation-intensive data points can be avoided without loss of prediction quality.
      Citation: Fibers
      PubDate: 2021-02-01
      DOI: 10.3390/fib9020008
      Issue No: Vol. 9, No. 2 (2021)
  • Fibers, Vol. 9, Pages 9: Raman Assisted Fiber Optical Parametric Amplifier
           for S-Band Multichannel Transmission System

    • Authors: Andis Supe, Kaspars Zakis, Lilita Gegere, Dmitrii Redka, Jurgis Porins, Sandis Spolitis, Vjaceslavs Bobrovs
      First page: 9
      Abstract: In this paper we present results from the study of optical signal amplification using Raman assisted fiber optical parametric amplifier with considerable benefits for S-band telecommunication systems where the use of widely used erbium-doped fiber amplifier is limited. We have created detailed models and performed computer simulations of combined Raman and fiber optical parametric amplification in a 16-channel 40 Gbps/channel wavelength division multiplexed transmission system. Achieved gain bandwidth, as well as transmission system parameters—signal-to-noise ratio and bit-error-ratio—were analyzed by comparing the Raman assisted fiber optical parametric amplifier to the single pump fiber optical parametric amplifier. Results show that the 3 dB gain bandwidth in the case of combined amplification is up to 0.2 THz wider with 1.9 dB difference between the lowest and highest gain.
      Citation: Fibers
      PubDate: 2021-02-01
      DOI: 10.3390/fib9020009
      Issue No: Vol. 9, No. 2 (2021)
  • Fibers, Vol. 9, Pages 10: Textiles Functionalized with ZnO Nanoparticles
           Obtained by Chemical and Green Synthesis Protocols: Evaluation of the Type
           of Textile and Resistance to UV Radiation

    • Authors: David Asmat-Campos, Daniel Delfín-Narciso, Luisa Juárez-Cortijo
      First page: 10
      Abstract: The study evaluates five types of commercial textiles with different cotton and polyester contents widely used in the garment industry. These textile samples have been subjected to treatment by the exhaustion method using zinc oxide nanoparticles (NP ZnO) (textile functionalization) with the aim of improving their efficiency in blocking UV radiation. The ZnO nanoparticles have been obtained by two methods: The green or also called biosynthesis (using the extract of Coriandrum sativum as an organic reducing agent), and the chemical method (using NaOH as an inorganic reducing agent). The results related to the green method show having achieved a defined geometric configuration with an average size of 97.77 nm (SD: 9.53). On the contrary, the nanostructures obtained by the chemical method show pentagonal configurations with average sizes of 113 nm (SD: 6.72). The textiles functionalized with NP ZnO obtained by biosynthesis showed a better efficiency in blocking ultraviolet radiation (UV).
      Citation: Fibers
      PubDate: 2021-02-01
      DOI: 10.3390/fib9020010
      Issue No: Vol. 9, No. 2 (2021)
  • Fibers, Vol. 9, Pages 11: Mechanical Properties of Phormium Tenax
           Reinforced Natural Rubber Composites

    • Authors: Sivasubramanian Palanisamy, Kalimuthu Mayandi, Murugesan Palaniappan, Azeez Alavudeen, Nagarajan Rajini, Felipe Vannucchi de Camargo, Carlo Santulli
      First page: 11
      Abstract: The introduction of natural fibers as a filler in a natural rubber (NR) matrix can be of relevance for their eco-friendly and sustainable nature as the substitute for carbon-based fillers. In this work, short Phormium tenax fibers were introduced in random orientation into a NR matrix in different lengths (6, 10, and 14 mm) and various amounts (10, 20, and 30%, taking 100 as the NR weight). The composite was fabricated using a two-roll mill according to American Society for Testing and Materials (ASTM) D3184-11 standard. Several properties were determined, namely tensile and tear characteristics, hardness, and abrasion resistance. The results suggest that the shortest fiber length used, 6 mm, offered the best combination between loss of mechanical (tensile and tear) properties and hardness and the most acceptable resistance to abrasion, with the properties increasing with the amount of fibers present in NR. As a consequence, it is indicated that a higher amount of fibers could be possibly introduced, especially to achieve harder composites, though this would require a more controlled mixing process not excessively reducing tensile elongation at break.
      Citation: Fibers
      PubDate: 2021-02-01
      DOI: 10.3390/fib9020011
      Issue No: Vol. 9, No. 2 (2021)
  • Fibers, Vol. 9, Pages 12: A Review on Electrospun PVC Nanofibers:
           Fabrication, Properties, and Application

    • Authors: Le Quoc Pham, Mayya V. Uspenskaya, Roman O. Olekhnovich, Rigel Antonio Olvera Bernal
      First page: 12
      Abstract: Polyvinyl chloride (PVC) is a widely used polymer, not only in industry, but also in our daily life. PVC is a material that can be applied in many different fields, such as building and construction, health care, and electronics. In recent decades, the success of electrospinning technology to fabricate nanofibers has expanded the applicability of polymers. PVC nanofibers have been successfully manufactured by electrospinning. By changing the initial electrospinning parameters, it is possible to obtain PVC nanofibers with diameters ranging from a few hundreds of nanometers to several micrometers. PVC nanofibers have many advantages, such as high porosity, high mechanical strength, large surface area, waterproof, and no toxicity. PVC nanofibers have been found to be very useful in many fields with a wide variety of applications such as air filtration systems, water treatment, oil spill treatment, batteries technology, protective clothing, corrosion resistance, and many others. This paper reviews the fabricating method, properties, applications, and prospects of PVC nanofibers.
      Citation: Fibers
      PubDate: 2021-02-03
      DOI: 10.3390/fib9020012
      Issue No: Vol. 9, No. 2 (2021)
  • Fibers, Vol. 9, Pages 13: Identification of the Physical and Mechanical
           Properties of Moroccan Sisal Yarns Used as Reinforcements for Composite

    • Authors: Zineb Samouh, Omar Cherkaoui, Damien Soulat, Ahmad Rashed Labanieh, François Boussu, Reddad El moznine
      First page: 13
      Abstract: This work aims to investigate the physical and mechanical properties of sisal fiber and yarn of Moroccan origin. The cellulosic and non-cellulosic constituents of the Moroccan sisal fiber were identified by FTIR spectroscopy. The thermal properties were studied by thermogravimetric analysis. The hydrophilicity of the fiber was evaluated by the contact angle. The results show that the sisal fiber has a low thermal stability. The mechanical properties of the fiber analyzed by the Impregnated Fiber Bundle Test (IFBT) method show that the porosity of the impregnated yarns and the twist angle of the yarns influence the elastic modulus of the sisal fiber. The physical and mechanical properties of the manufactured sisal yarns were also characterized and analyzed. The obtained results reveal an interesting potential to use the Moroccan sisal fiber in development of bio-sourced composite materials.
      Citation: Fibers
      PubDate: 2021-02-05
      DOI: 10.3390/fib9020013
      Issue No: Vol. 9, No. 2 (2021)
  • Fibers, Vol. 9, Pages 1: Numerical Method for Coupled Nonlinear
           Schrödinger Equations in Few-Mode Fiber

    • Authors: Airat Zh. Sakhabutdinov, Vladimir I. Anfinogentov, Oleg G. Morozov, Vladimir A. Burdin, Anton V. Bourdine, Artem A. Kuznetsov, Dmitry V. Ivanov, Vladimir A. Ivanov, Maria I. Ryabova, Vladimir V. Ovchinnikov
      First page: 1
      Abstract: This paper discusses novel approaches to the numerical integration of the coupled nonlinear Schrödinger equations system for few-mode wave propagation. The wave propagation assumes the propagation of up to nine modes of light in an optical fiber. In this case, the light propagation is described by the non-linear coupled Schrödinger equation system, where propagation of each mode is described by own Schrödinger equation with other modes’ interactions. In this case, the coupled nonlinear Schrödinger equation system (CNSES) solving becomes increasingly complex, because each mode affects the propagation of other modes. The suggested solution is based on the direct numerical integration approach, which is based on a finite-difference integration scheme. The well-known explicit finite-difference integration scheme approach fails due to the non-stability of the computing scheme. Owing to this, here we use the combined explicit/implicit finite-difference integration scheme, which is based on the implicit Crank–Nicolson finite-difference scheme. It ensures the stability of the computing scheme. Moreover, this approach allows separating the whole equation system on the independent equation system for each wave mode at each integration step. Additionally, the algorithm of numerical solution refining at each step and the integration method with automatic integration step selection are used. The suggested approach has a higher performance (resolution)—up to three times or more in comparison with the split-step Fourier method—since there is no need to produce direct and inverse Fourier transforms at each integration step. The key advantage of the developed approach is the calculation of any number of modes propagated in the fiber.
      Citation: Fibers
      PubDate: 2021-01-02
      DOI: 10.3390/fib9010001
      Issue No: Vol. 9, No. 1 (2021)
  • Fibers, Vol. 9, Pages 2: The Mechanical Properties of PVC Nanofiber Mats
           Obtained by Electrospinning

    • Authors: Quoc Pham Le, Mayya V. Uspenskaya, Roman O. Olekhnovich, Mikhail A. Baranov
      First page: 2
      Abstract: This paper investigates the mechanical properties of oriented polyvinyl chloride (PVC) nanofiber mats, which, were obtained by electrospinning a PVC solution. PVC was dissolved in a solvent mixture of tetrahydrofuran/dimethylformamide. Electrospinning parameters used in our work were, voltage 20 kV; flow rate 0.5 mL/h; the distance between the syringe tip and collector was 15 cm. The rotating speed of the drum collector was varied from 500 to 2500 rpm with a range of 500 rpm. Nanofiber mats were characterized by scanning electron microscope, thermogravimetric analysis, differential scanning calorimetry methods. The mechanical properties of PVC nanofiber mats, such as tensile strength, Young’s modulus, thermal degradation, and glass transition temperature were also analyzed. It was shown that, by increasing the collector’s rotation speed from 0 (flat plate collector) to 2500 rpm (drum collector), the average diameter of PVC nanofibers decreased from 313 ± 52 to 229 ± 47 nm. At the same time, it was observed that the mechanical properties of the resulting nanofiber mats were improved: tensile strength increased from 2.2 ± 0.2 MPa to 9.1 ± 0.3 MPa, Young’s modulus from 53 ± 14 to 308 ± 19 MPa. Thermogravimetric analysis measurements showed that there was no difference in the process of thermal degradation of nanofiber mats and PVC powders. On the other hand, the glass transition temperature of nanofiber mats and powders did show different values, such values were 77.5 °C and 83.2 °C, respectively.
      Citation: Fibers
      PubDate: 2021-01-05
      DOI: 10.3390/fib9010002
      Issue No: Vol. 9, No. 1 (2021)
  • Fibers, Vol. 9, Pages 3: New Textile for Personal Protective
           Equipment—Plasma Chitosan/Silver Nanoparticles Nylon Fabric

    • Authors: Cláudia M. Botelho, Margarida M. Fernandes, Jefferson M. Souza, Nicolina Dias, Ana M. Sousa, José A. Teixeira, Raul Fangueiro, Andrea Zille
      First page: 3
      Abstract: Fabric structures are prone to contamination with microorganisms, as their morphology and ability to retain moisture creates a proper environment for their growth. In this work, a novel, easily processed and cheap coating for a nylon fabric with antimicrobial characteristics was developed. After plasma treatment, made to render the fabric surface more reactive sites, the fabric was impregnated with chitosan and silver nanoparticles by simply dipping it into a mixture of different concentrations of both components. Silver nanoparticles were previously synthesized using the Lee–Meisel method, and their successful obtention was proven by UV–Vis, showing the presence of the surface plasmon resonance band at 410 nm. Nanoparticles with 25 nm average diameter observed by STEM were stable, mainly in the presence of chitosan, which acted as a surfactant for silver nanoparticles, avoiding their aggregation. The impregnated fabric possessed bactericidal activity higher for Gram-positive Staphylococcus aureus than for Gram-negative Pseudomonas aeruginosa bacteria for all combinations. The percentage of live S. aureus and P. aeruginosa CFU was reduced to less than 20% and 60%, respectively, when exposed to each of the coating combinations. The effect was more pronounced when both chitosan and silver were present in the coating, suggesting an effective synergy between these components. After a washing process, the antimicrobial effect was highly reduced, suggesting that the coating is unstable after washing, being almost completely removed from the fabric. Nevertheless, the new-coated fabric can be successfully used in single-use face masks. To our knowledge, the coating of nylon fabrics intended for face-mask material with both agents has never been reported.
      Citation: Fibers
      PubDate: 2021-01-06
      DOI: 10.3390/fib9010003
      Issue No: Vol. 9, No. 1 (2021)
  • Fibers, Vol. 9, Pages 4: Mechanical and Dielectric Properties of Aligned
           Electrospun Fibers

    • Authors: Blesson Isaac, Robert M. Taylor, Kenneth Reifsnider
      First page: 4
      Abstract: This review paper examines the current state-of-the-art in fabrication of aligned fibers via electrospinning techniques and the effects of these techniques on the mechanical and dielectric properties of electrospun fibers. Molecular orientation, system configuration to align fibers, and post-drawing treatment, like hot/cold drawing process, contribute to better specific strength and specific stiffness properties of nanofibers. The authors suggest that these improved, aligned nanofibers, when applied in composites, have better mechanical and dielectric properties for many structural and multifunctional applications, including advanced aerospace applications and energy storage devices. For these applications, most fiber alignment electrospinning research has focused on either mechanical property improvement or dielectric property improvement alone, but not both simultaneously. Relative to many other nanofiber formation techniques, the electrospinning technique exhibits superior nanofiber formation when considering cost and manufacturing complexity for many situations. Even though the dielectric property of pure nanofiber mat may not be of general interest, the analysis of the combined effect of mechanical and dielectric properties is relevant to the present analysis of improved and aligned nanofibers. A plethora of nanofibers, in particular, polyacrylonitrile (PAN) electrospun nanofibers, are discussed for their mechanical and dielectric properties. In addition, other types of electrospun nanofibers are explored for their mechanical and dielectric properties. An exploratory study by the author demonstrates the relationship between mechanical and dielectric properties for specimens obtained from a rotating mandrel horizontal setup.
      Citation: Fibers
      PubDate: 2021-01-06
      DOI: 10.3390/fib9010004
      Issue No: Vol. 9, No. 1 (2021)
  • Fibers, Vol. 9, Pages 5: Cellulose Dissolution in Ionic Liquid under Mild
           Conditions: Effect of Hydrolysis and Temperature

    • Authors: Sanjit Acharya, Yang Hu, Noureddine Abidi
      First page: 5
      Abstract: This study investigated the effect of acid hydrolysis of cellulose on its dissolution under mild conditions in ionic liquid, 1-butyl-3-methylimidazolium acetate/N,N-dimethylacetamide (BMIMAc/DMAc). Acid hydrolysis of high molecular weight (MW) cotton cellulose (DP > 4000) was carried out to produce hydrolyzed cotton (HC) samples for dissolution. The HC samples were characterized using gel permeation chromatography (GPC), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA), and the dissolution process was monitored using polarized light microscopy (PLM). It was found that the drastic decrease of the MW of cellulose did not result in improvement of its dissolution at room temperature. As compared to original cotton cellulose, the high amount of undissolved fibers in HC solutions led to unstable rheological behavior of HC solutions. Agglomeration and inhomogeneous dispersion of HC, and increased crystallinity, in this case, likely made the diffusion of BMIMAc/DMAc more difficult to the inside of the polymeric network of cellulose at ambient temperature, thereby hindering the dissolution. However, increasing the temperature from room temperature to 35 °C and 55 °C, led to a significant improvement in cellulose dissolution. This phenomenon implies that reducing the MW of cellulose might not be able to improve its dissolution under certain conditions. During the dissolution process, the physical properties of cellulose including fiber aggregation status, solvent diffusivity, and cellulose crystallinity may play a critical role compared to the MW, while the MW may not be an important factor. This finding may help further understand the mechanism of cellulose dissolution and seek better strategies to dissolve cellulose under mild conditions for industrial applications.
      Citation: Fibers
      PubDate: 2021-01-06
      DOI: 10.3390/fib9010005
      Issue No: Vol. 9, No. 1 (2021)
  • Fibers, Vol. 9, Pages 6: Techniques for Modelling and Optimizing the
           Mechanical Properties of Natural Fiber Composites: A Review

    • Authors: Timothy K. Mulenga, Albert U. Ude, Chinnasamy Vivekanandhan
      First page: 6
      Abstract: The study of natural fiber-based composites through the use of computational techniques for modelling and optimizing their properties has emerged as a fast-growing approach in recent years. Ecological concerns associated with synthetic fibers have made the utilisation of natural fibers as a reinforcing material in composites a popular approach. Computational techniques have become an important tool in the hands of many researchers to model and analyze the characteristics that influence the mechanical properties of natural fiber composites. This recent trend has led to the development of many advanced computational techniques and software for a profound understanding of the characteristics and performance behavior of composite materials reinforced with natural fibers. The large variations in the characteristics of natural fiber-based composites present a great challenge, which has led to the development of many computational techniques for composite materials analysis. This review seeks to infer, from conventional to contemporary sources, the computational techniques used in modelling, analyzing, and optimizing the mechanical characteristics of natural fiber reinforced composite materials.
      Citation: Fibers
      PubDate: 2021-01-14
      DOI: 10.3390/fib9010006
      Issue No: Vol. 9, No. 1 (2021)
  • Fibers, Vol. 9, Pages 7: Acknowledgment to Reviewers of Fibers in 2020

    • Authors: Fibers Editorial Office Fibers Editorial Office
      First page: 7
      Abstract: Peer review is the driving force of journal development, and reviewers are gatekeepers who ensure that Fibers maintains its standards for the high quality of its published papers [...]
      Citation: Fibers
      PubDate: 2021-01-19
      DOI: 10.3390/fib9010007
      Issue No: Vol. 9, No. 1 (2021)
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