Open AccessArticle
Effect of Bitumen and Polyester Resin Mixture on the Physico-Mechanical and Degradable Properties of Jute Fabrics
Fibers 2018, 6(3), 44; https://doi.org/10.3390/fib6030044 (registering DOI) -
Abstract
Jute fabric samples were treated, with different formulations, using various proportions of bitumen emulsion and polyester (PE) resin in combined solutions. Styrene monomer was used as solvent, methyl ethyl ketone peroxide as cross-linking agent and cobalt naphtha as curing agent. The fabric specimens
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Jute fabric samples were treated, with different formulations, using various proportions of bitumen emulsion and polyester (PE) resin in combined solutions. Styrene monomer was used as solvent, methyl ethyl ketone peroxide as cross-linking agent and cobalt naphtha as curing agent. The fabric specimens were immersed in the solution for 10–15 min, then pressed by a roller and dried at room temperature for 24 h. According to the percentage of bitumen emulsion and PE resin, the jute samples were obtained as J0 (untreated or raw jute), J1 (20% bitumen emulsion +10% PE), and J2 (10% bitumen emulsion +20% PE). It was revealed that tensile strength (TS) increased with bitumen emulsion and PE resin mixture treatment on both directions of jute fabrics where J2 showed the highest improvement of TS which were 61.4% and 44.7% for warp and weft direction respectively. Tensile strength (TS) decreased for all the samples in both directions after soil degradation. After 90 days, the untreated sample was totally degraded. Treated samples exhibited better stability than untreated ones in soil medium. Weight loss by soil degradation, moisture regain, moisture content and water uptake tests of the treated and untreated jute samples were also performed. Scanning electron microscopy (SEM) analysis was conducted to analyze the fiber surfaces of raw and treated jute fibers, finding significant differences as a result of treatment. Finally, the strategy of combining bitumen emulsion and PE resin for treatment, rather than using only PE resin, was found to produce a jute fabric which was not only better in all the above respects but also would be cheaper to produce. Full article
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Open AccessReview
3D Printed Hollow-Core Terahertz Fibers
Fibers 2018, 6(3), 43; https://doi.org/10.3390/fib6030043 -
Abstract
This paper reviews the subject of 3D printed hollow-core fibers for the propagation of terahertz (THz) waves. Several hollow and microstructured core fibers have been proposed in the literature as candidates for low-loss terahertz guidance. In this review, we focus on 3D printed
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This paper reviews the subject of 3D printed hollow-core fibers for the propagation of terahertz (THz) waves. Several hollow and microstructured core fibers have been proposed in the literature as candidates for low-loss terahertz guidance. In this review, we focus on 3D printed hollow-core fibers with designs that cannot be easily created by conventional fiber fabrication techniques. We first review the fibers according to their guiding mechanism: photonic bandgap, antiresonant effect, and Bragg effect. We then present the modeling, fabrication, and characterization of a 3D printed Bragg and two antiresonant fibers, highlighting the advantages of using 3D printers as a path to make the fabrication of complex 3D fiber structures fast and cost-effective. Full article
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Open AccessArticle
Effect of Nested Elements on Avoided Crossing between the Higher-Order Core Modes and the Air-Capillary Modes in Hollow-Core Antiresonant Optical Fibers
Fibers 2018, 6(2), 42; https://doi.org/10.3390/fib6020042 -
Abstract
Optimal suppression of higher-order modes (HOMs) in hollow-core antiresonant fibers comprising a single ring of thin-walled capillaries was previously studied, and can be achieved when the condition on the capillary-to-core diameter ratio is satisfied (d/D0.68).
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Optimal suppression of higher-order modes (HOMs) in hollow-core antiresonant fibers comprising a single ring of thin-walled capillaries was previously studied, and can be achieved when the condition on the capillary-to-core diameter ratio is satisfied (d/D0.68). Here we report on the conditions for maximizing the leakage losses of HOMs in hollow-core nested antiresonant node-less fibers, while preserving low confinement loss for the fundamental mode. Using an analytical model based on coupled capillary waveguides, as well as full-vector finite element modeling, we show that optimal d/D value leading to high leakage losses of HOMs, is strongly correlated to the size of nested capillaries. We also show that extremely high value of degree of HOM suppression (∼1200) at the resonant coupling is almost unchanged on a wide range of nested capillary diameter dNested values. These results therefore suggest the possibility of designing antiresonant fibers with nested elements, which show optimal guiding performances in terms of the HOM loss compared to that of the fundamental mode, for clearly defined paired values of the ratios dNested/d and d/D. These can also tend towards a single-mode behavior only when the dimensionless parameter dNested/d is less than 0.30, with identical wall thicknesses for all of the capillaries. Full article
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Open AccessArticle
Fluoropolymer-Wrapped Conductive Threads for Textile Touch Sensors Operating via the Triboelectric Effect
Fibers 2018, 6(2), 41; https://doi.org/10.3390/fib6020041 -
Abstract
Touch-sensitive electrical arrays are the primary user interface for modern consumer electronics. Most contemporary touch sensors, including known iterations of textile-based touch sensors, function by detecting capacitive changes within a circuit resulting from direct skin contact. However, this method of operation fails when
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Touch-sensitive electrical arrays are the primary user interface for modern consumer electronics. Most contemporary touch sensors, including known iterations of textile-based touch sensors, function by detecting capacitive changes within a circuit resulting from direct skin contact. However, this method of operation fails when the user’s skin or the surface of the touch sensor is dirty, oily or wet, preventing practical use of textile-based touch sensors in real-world scenarios. Here, an electrically touch-responsive woven textile is described, which is composed of fluoropolymer-wrapped conductive threads. The fluoropolymer wrapping prevents contaminant buildup on the textile surface and also electrically insulates the conductive thread core. The woven textile touch sensor operates via surface potential changes created upon skin contact. This method of operation, called the triboelectric effect, has not been widely used to create textile touch sensors, to date. The influences of surface wetness and varying skin surface chemistry are studied, and the triboelectric textile touch sensors are found to be advantageously insensitive to these environmental variables, indicating that triboelectric textiles have promise for practical use as touch interfaces in furniture and interior design. Full article
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Open AccessArticle
Mechanical Properties of a Water Hyacinth Nanofiber Cellulose Reinforced Thermoplastic Starch Bionanocomposite: Effect of Ultrasonic Vibration during Processing
Fibers 2018, 6(2), 40; https://doi.org/10.3390/fib6020040 -
Abstract
Thermoplastic starch (TPS) reinforced by 1 wt % nanofiber cellulose (NFC) reinforcing from water hyacinth was produced. Ultrasonic vibration time (UVT) was applied to bionanocomposites during gelation for 0, 15, 30 and 60 min. Morphology of the NFC was investigated using Transmission Electron
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Thermoplastic starch (TPS) reinforced by 1 wt % nanofiber cellulose (NFC) reinforcing from water hyacinth was produced. Ultrasonic vibration time (UVT) was applied to bionanocomposites during gelation for 0, 15, 30 and 60 min. Morphology of the NFC was investigated using Transmission Electron Microscopy (TEM). Scanning Electron Microscopy (SEM) and tensile tests were performed to identify the fracture surface and determine the mechanical properties of the bionanocomposites, respectively. The Crystallinity index (CI) of untreated and treated bionanocomposites was measured using X-ray Diffraction (XRD). The average diameter of NFC water hyacinth was 10–20 nm. The maximum tensile strength (TS) and modulus elasticity (ME) of the bionanocomposite was 11.4 MPa and 443 MPa respectively, after 60 min UVT. This result was supported by SEM which indicated good dispersion and compact structure. Full article
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Open AccessReview
Revolver Hollow Core Optical Fibers
Fibers 2018, 6(2), 39; https://doi.org/10.3390/fib6020039 -
Abstract
Revolver optical fibers (RF) are special type of hollow-core optical fibers with negative curvature of the core-cladding boundary and with cladding that is formed by a one ring layer of capillaries. The physical mechanisms contributing to the waveguiding parameters of RFs are discussed.
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Revolver optical fibers (RF) are special type of hollow-core optical fibers with negative curvature of the core-cladding boundary and with cladding that is formed by a one ring layer of capillaries. The physical mechanisms contributing to the waveguiding parameters of RFs are discussed. The optical properties and possible applications of RFs are reviewed. Special attention is paid to the mid-IR hydrogen Raman lasers that are based on RFs and generating in the wavelength region from 2.9 to 4.4 μm. Full article
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Open AccessArticle
Behavior of Concrete under the Addition of High Volume of Polyolefin Macro Fiber and Fly Ash
Fibers 2018, 6(2), 38; https://doi.org/10.3390/fib6020038 -
Abstract
This paper deals with behavior of concrete’s compressive and bending strengths with the addition of high amount of polyolefin macro fibers. Polyolefin fiber is used to increase the bending strength and compressive strength, these experiments are done to investigate the cracking behavior and
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This paper deals with behavior of concrete’s compressive and bending strengths with the addition of high amount of polyolefin macro fibers. Polyolefin fiber is used to increase the bending strength and compressive strength, these experiments are done to investigate the cracking behavior and found the bending strength and compressive strength of polyolefin fiber reinforced concrete. Normally, concrete is mixed with various amount of fiber, but in this experiment five different specimens were prepared, S-1 is without fiber; S-2, homogeneous mixing of fiber volume of 10 kg/m3; S-3, homogeneous mixing of fiber volume of 25 kg/m3; S-4, homogeneous mixing of fiber volume of 35 kg/m3; and S-5, which contains 25 kg/m3 fiber mixed by hand in three different layers. A small amount of fly ash (18.18% of cement mass) is also mixed in the concrete specimens for better results. Concrete specimens were tested on 7th day and 28th day of the curing process. Water absorption capacity and compressive strength tests were done in the dry state and wet state to find the strength difference. More than 50% of flexural strength was gained on the 28th day of the destructive test. Post-cracking behavior was observed on the 28th day of the test, the specimens with fiber content were found to take load after cracking and hold more load to failure. Full article
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Open AccessFeature PaperArticle
PA6 Nanofibre Production: A Comparison between Rotary Jet Spinning and Electrospinning
Fibers 2018, 6(2), 37; https://doi.org/10.3390/fib6020037 -
Abstract
Polymer nanofibres are created from many different techniques, with varying rates of production. Rotary jet spinning is a relatively new technique for making nanofibres from both polymer solutions and melt. With electrospinning being by far the most widespread processing method for polymer nanofibres,
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Polymer nanofibres are created from many different techniques, with varying rates of production. Rotary jet spinning is a relatively new technique for making nanofibres from both polymer solutions and melt. With electrospinning being by far the most widespread processing method for polymer nanofibres, we performed a direct comparison of polyamide 6 (PA6) nanofibre production between these two methods. It was found that electrospinning produced slightly smaller-diameter fibres, which scaled with a decrease in solution viscosity. In comparison, rotary jet spun fibres could be produced from a reduced range of polymer concentrations and exhibited therefore slightly larger diameters with greater variation. Crystallinity of the fibres was also compared between the two techniques and the bulk polymer, which showed a decrease in crystallinity compared to bulk PA6. Full article
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Open AccessArticle
Flame Retardant Multilayered Coatings on Acrylic Fabrics Prepared by One-Step Deposition of Chitosan/Montmorillonite Complexes
Fibers 2018, 6(2), 36; https://doi.org/10.3390/fib6020036 -
Abstract
Multilayered coatings deposited using the layer-by-layer (LbL) assembly technique have attracted great interest in recent years as a sustainable and efficient solution for conferring flame retardant properties to fabrics. The unique structure and interaction established upon the coating assembly are the key factors
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Multilayered coatings deposited using the layer-by-layer (LbL) assembly technique have attracted great interest in recent years as a sustainable and efficient solution for conferring flame retardant properties to fabrics. The unique structure and interaction established upon the coating assembly are the key factors for successful flame retardant properties. In this study we aimed at the deposition of multilayered coatings comprising chitosan and montmorillonite with a LbL-like structure and interactions by the simple processing of compacted chitosan/montmorillonite complexes obtained by the direct mixing of an oppositely charged solution/suspension. Upon drying, the prepared complex yielded a continuous coating characterized by a brick-and-mortar multi-layered structure, in which oriented clay nanoplatelets were held together by a continuous chitosan matrix. When deposited on acrylic fabrics these coatings were able to suppress the melt-dripping phenomenon, and at 10 and 20% add-ons achieved self-extinguishing behavior within a few seconds after ignition. Cone calorimetry testing revealed an increase in time to ignition (up to +46%) and considerable reductions of the rates at which heat is released (up to −62 and −49% for peak of heat release rate and total heat release, respectively). A reduction in the total smoke release (up to −49%) was also observed. Full article
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Open AccessArticle
Engineering a Costume for Performance Using Illuminated LED-Yarns
Fibers 2018, 6(2), 35; https://doi.org/10.3390/fib6020035 -
Abstract
A goal in the field of wearable technology is to blend electronics with textile fibers to create garments that drape and conform as normal, with additional functionality provided by the embedded electronics. This can be achieved with electronic yarns (E-yarns), in which electronics
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A goal in the field of wearable technology is to blend electronics with textile fibers to create garments that drape and conform as normal, with additional functionality provided by the embedded electronics. This can be achieved with electronic yarns (E-yarns), in which electronics are integrated within the fibers of a yarn. A challenge is incorporating non-stretch E-yarns with stretch fabric that is desirable for some applications. To address this challenge, E-yarns containing LEDs were embroidered onto the stretch fabric of a unitard used as part of a carnival costume. A zig-zag pattern of attachment of E-yarns was developed. Tensile testing showed this pattern was successful in preventing breakages within the E-yarns. Use in performance demonstrated that a dancer was unimpeded by the presence of the E-yarns within the unitard, but also a weakness in the junctions between E-yarns was observed, requiring further design work and reinforcement. The level of visibility of the chosen red LEDs within black E-yarns was low. The project demonstrated the feasibility of using E-yarns with stretch fabrics. This will be particularly useful in applications where E-yarns containing sensors are required in close contact with skin to provide meaningful on-body readings, without impeding the wearer. Full article
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Open AccessReview
A Historical Review of the Development of Electronic Textiles
Fibers 2018, 6(2), 34; https://doi.org/10.3390/fib6020034 -
Abstract
Textiles have been at the heart of human technological progress for thousands of years, with textile developments closely tied to key inventions that have shaped societies. The relatively recent invention of electronic textiles is set to push boundaries again and has already opened
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Textiles have been at the heart of human technological progress for thousands of years, with textile developments closely tied to key inventions that have shaped societies. The relatively recent invention of electronic textiles is set to push boundaries again and has already opened up the potential for garments relevant to defense, sports, medicine, and health monitoring. The aim of this review is to provide an overview of the key innovative pathways in the development of electronic textiles to date using sources available in the public domain regarding electronic textiles (E-textiles); this includes academic literature, commercialized products, and published patents. The literature shows that electronics can be integrated into textiles, where integration is achieved by either attaching the electronics onto the surface of a textile, electronics are added at the textile manufacturing stage, or electronics are incorporated at the yarn stage. Methods of integration can have an influence on the textiles properties such as the drapability of the textile. Full article
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Open AccessArticle
Antimicrobial Activity of Poly(ester urea) Electrospun Fibers Loaded with Bacteriophages
Fibers 2018, 6(2), 33; https://doi.org/10.3390/fib6020033 -
Abstract
The capacity to load bacteriophages into electrospun nanofibers of two representative biocompatible polymers has been evaluated, paying special attention to the possibility of preserving their antibacterial activity. Specifically, the work involves the following steps: (a) Evaluation of the effect of the applied electrical
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The capacity to load bacteriophages into electrospun nanofibers of two representative biocompatible polymers has been evaluated, paying special attention to the possibility of preserving their antibacterial activity. Specifically, the work involves the following steps: (a) Evaluation of the effect of the applied electrical field on the phage activity; (b) evaluation of the activity when a lyophilization process could be avoided by using water soluble polymers (e.g., poly(ethylene glycol); (c) evaluation of the activity when dissolution of the polymer requires an organic solvent and lyophilization is theoretically necessary. In this case, a poly(ester urea) (PEU) derived from the natural L-leucine amino acid has been considered. Adsorption of commercial bacteriophage preparations into calcium carbonate particles was demonstrated to be a promising methodology to avoid lyophilization and keep the initial bactericide activity at a maximum. Phagestaph and Fersis bacteriophage commercial preparations have been selected for this study due to their specific activity against Staphylococci (e.g., S. aureus) and Streptococci (e.g., S. pyogenes) bacteria. Adhesion and proliferation assays using epithelial cells demonstrated the biocompatibility of both unloaded and bacteriophage-loaded PEU scaffolds, although some slight differences were observed depending on the type of bacteriophage and the selected preparation methodology. Full article
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Open AccessArticle
Photon-Pair Sources Based on Intermodal Four-Wave Mixing in Few-Mode Fibers
Fibers 2018, 6(2), 32; https://doi.org/10.3390/fib6020032 -
Abstract
Four-wave mixing in optical fibers has been proven to have many applications within processing of classical optical signals. In addition, recent developments in multimode fibers have made it possible to achieve the necessary phase-matching for efficient four-wave mixing over a very wide bandwidth.
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Four-wave mixing in optical fibers has been proven to have many applications within processing of classical optical signals. In addition, recent developments in multimode fibers have made it possible to achieve the necessary phase-matching for efficient four-wave mixing over a very wide bandwidth. Thus, the combination of multimode fiber optics and four-wave mixing is very attractive for various applications. This is especially the case for applications in quantum communication, for example in photon-pair generation. This is the subject of this work, where we discuss the impact of fluctuations in core radius on the quality of the heralded single-photon states and demonstrate experimental results of intermodal spontaneous four-wave mixing for photon-pair generation. Full article
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Open AccessArticle
Environmentally Sustainable Flame Retardant Surface Treatments for Textiles: The Potential of a Novel Atmospheric Plasma/UV Laser Technology
Fibers 2018, 6(2), 31; https://doi.org/10.3390/fib6020031 -
Abstract
Conventional flame retardant (FR) application processes for textiles involve aqueous processing which is resource-intensive in terms of energy and water usage. Recent research using sol-gel and layer-by-layer chemistries, while claimed to be based on more environmentally sustainable chemistry, still require aqueous media with
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Conventional flame retardant (FR) application processes for textiles involve aqueous processing which is resource-intensive in terms of energy and water usage. Recent research using sol-gel and layer-by-layer chemistries, while claimed to be based on more environmentally sustainable chemistry, still require aqueous media with the continuing problem of water management and drying processes being required. This paper outlines the initial forensic work to characterise commercially produced viscose/flax, cellulosic furnishing fabrics which have had conferred upon them durable flame retardant (FR) treatments using a novel, patented atmospheric plasma/Ultraviolet (UV) excimer laser facility for processing textiles with the formal name Multiplexed Laser Surface Enhancement (MLSE) system. This system (MTIX Ltd., Huddersfield, UK) is claimed to offer the means of directly bonding of flame retardant precursor species to the component fibres introduced either before plasma/UV exposure or into the plasma/UV reaction zone itself; thereby eliminating a number of wet processing cycles. Nine commercial fabrics, pre-impregnated with a semi-durable, proprietary FR finish and subjected to the MLSE process have been analysed for their flame retardant properties before and after a 40 °C 30 min water soak. For one fabric, the pre-impregnated fabric was subjected to a normal heat cure treatment which conferred the same level of durability as the plasma/UV-treated analogue. Thermogravimetric analysis (TGA) and limiting oxygen index (LOI) were used to further characterise their burning behaviour and the effect of the treatment on surface fibre morphologies were assessed. Scanning electron microscopy indicated that negligible changes had occurred to surface topography of the viscose fibres occurred during plasma/UV excimer processing. Full article
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Open AccessArticle
Indirect Tensile Behaviour of Fibre Reinforced Alkali-Activated Composites
Fibers 2018, 6(2), 30; https://doi.org/10.3390/fib6020030 -
Abstract
There are currently still some sustainability-related issues that need to be tackled within the construction sector. Namely, cement production is accountable for nearby 5% of the worldwide total CO2-eq release. Therefore, environmentally viable and economically sustainable solutions need to be pursued
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There are currently still some sustainability-related issues that need to be tackled within the construction sector. Namely, cement production is accountable for nearby 5% of the worldwide total CO2-eq release. Therefore, environmentally viable and economically sustainable solutions need to be pursued in order to mitigate the use of Portland cement. The incorporation of industrial waste in concrete compositions, such as fly ash (from coal combustion in power stations) is a feasible alternative. The properties of these residues may be enhanced through alkaline activation, which is able to yield aluminosilicate-based materials with excellent physico-chemical properties. Nonetheless, these materials exhibit a brittle behaviour. Therefore, the present work addresses the study of alkali-activated composites reinforced with sisal fibres. For that purpose, alkali-activated Class F fly ash was mixed with natural fibres and the composite mechanical behaviour was assessed through both indirect tensile and compressive tests. Four different fibre contents, in wt % of fly ash (0, 0.2, 0.6 and 1%), two fibre lengths (13 and 50 mm) and four curing periods (14, 28, 56 and 112 days) were considered. Results confirm that the post-cracking response of these composites was improved with the inclusion of sisal fibres. In general, higher residual tensile strengths and dissipated energy were observed for the lengthier fibres, i.e., 50 mm. Full article
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Open AccessArticle
Does Dietary Fiber Affect the Levels of Nutritional Components after Feed Formulation?
Fibers 2018, 6(2), 29; https://doi.org/10.3390/fib6020029 -
Abstract
Studies on dietary fiber and nutrient bioavailability have gained an increasing interest in both human and animal nutrition. Questions are increasingly being asked regarding the faith of nutrient components such as proteins, minerals, vitamins, and lipids after feed formulation. The aim of this
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Studies on dietary fiber and nutrient bioavailability have gained an increasing interest in both human and animal nutrition. Questions are increasingly being asked regarding the faith of nutrient components such as proteins, minerals, vitamins, and lipids after feed formulation. The aim of this review is to evaluate the evidence with the perspective of fiber usage in feed formulation. The consumption of dietary fiber may affect the absorption of nutrients in different ways. The physicochemical factors of dietary fiber, such as fermentation, bulking ability, binding ability, viscosity and gel formation, water-holding capacity and solubility affect nutrient absorption. The dietary fiber intake influences the different methods in which nutrients are absorbed. The increase in the total fiber content of the diet may delay the glycemic response. Soluble fiber decreased blood glucose content whereas purified insoluble fiber has a little or no effect on the blood glucose levels after a meal. Dietary fiber and prebiotics influence the host animal well-being by regulating blood glucose or insulin levels, stool bulking effects, increasing the acidity of the gut, constructive synthesis of short chain fatty acids (SCFAs), decreasing intestinal transit time, stimulating the growth of intestinal microbes, and increasing blood parameters. Previous studies suggest that fiber affects the bioavailability of nutrients, and maintains the host wellness. Full article
Open AccessArticle
Production of Nanocellulose from Pineapple Leaf Fibers via High-Shear Homogenization and Ultrasonication
Fibers 2018, 6(2), 28; https://doi.org/10.3390/fib6020028 -
Abstract
In this study, the isolation and characterization of nanocellulose from pineapple leaf fibers (PLF) were carried out. Chemical pretreatment included pulping, bleaching, and acid hydrolysis to remove lignin, hemicellulose, and extractive substances were conducted. This was followed by high-shear homogenization and ultrasonication to
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In this study, the isolation and characterization of nanocellulose from pineapple leaf fibers (PLF) were carried out. Chemical pretreatment included pulping, bleaching, and acid hydrolysis to remove lignin, hemicellulose, and extractive substances were conducted. This was followed by high-shear homogenization and ultrasonication to produce nanocellulose. Morphological changes to the PLF due to treatment were investigated using scanning electron microscopy (SEM). This showed that the PLF had a diameter of 1–10 µm after high-shear homogenizing. Transmission electron microscopy (TEM) indicated that the nanofibers after ultrasonication for 60 min showed 40–70 nm diameters. Particle size analysis (PSA) indicates that the fibers had an average diameter of 68 nm. Crystallinity index was determined by X-ray diffraction (XRD) and had the highest value after acid hydrolysis at 83% but after 60 min ultrasonication, this decreased to 62%. Meanwhile, Fourier transform infrared (FTIR) spectroscopy showed there was no chemical structure change after acid hydrolysis. The most significant finding from thermal gravimetric analysis (TGA) is that the higher degradation temperature of nanofibers indicates superior thermal stability over untreated fiber. These results indicate that PLF waste could become a viable source of commercially valuable nanocellulose. Full article
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Open AccessArticle
Expression Analysis of Cell Wall-Related Genes in Cannabis sativa: The “Ins and Outs” of Hemp Stem Tissue Development
Fibers 2018, 6(2), 27; https://doi.org/10.3390/fib6020027 -
Abstract
Textile hemp (Cannabis sativa L.) is a multipurpose crop producing biomass with uses in e.g., the textile, biocomposite, and construction sectors. It was previously shown that the hypocotyl of hemp is useful to study the kinetics of secondary tissue development, where primary
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Textile hemp (Cannabis sativa L.) is a multipurpose crop producing biomass with uses in e.g., the textile, biocomposite, and construction sectors. It was previously shown that the hypocotyl of hemp is useful to study the kinetics of secondary tissue development, where primary and secondary growths are temporally uncoupled. We here sought to demonstrate that the stem of adult hemp plants is an additional suitable model to study the heterogeneous lignification of the tissues and the mechanisms underlying secondary cell wall formation in bast fibres. A targeted quantitative PCR analysis carried out on a set of twenty genes involved in cell wall biosynthesis clearly showed differences in expression in the core and cortical tissues along four stem regions spanning from elongation to cell wall thickening. Genes involved in phenylpropanoid biosynthesis and secondary cell wall cellulose synthases were expressed at higher levels in core tissues at the bottom, while specific genes, notably a class III peroxidase and a gene partaking in lignan biosynthesis, were highly expressed in the cortex of elongating internodes. The two systems, the hypocotyl and the adult stem of textile hemp, are equally valid and complementary to address questions related to lignification and secondary cell wall deposition. Full article
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Open AccessArticle
Various Extraction Methods Influence the Adhesive Properties of Dried Distiller’s Grains and Solubles, and Press Cakes of Pennycress (Thlaspi arvense L.) and Lesquerella [Lesquerella fendleri (A. Gary) S. Watson], in the Fabrication of Lignocellulosic Composites
Fibers 2018, 6(2), 26; https://doi.org/10.3390/fib6020026 -
Abstract
Lignocellulosic composite (LC) panels were fabricated using an adhesive matrix prepared from three different agricultural by-products: dried distillers grains with solubles (DDGS), pennycress (Thlaspi arvense L.) press cake (PPC), or lesquerella [Lesquerella fendleri (A. Gary) S. Watson] press cake (LPC) reinforced
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Lignocellulosic composite (LC) panels were fabricated using an adhesive matrix prepared from three different agricultural by-products: dried distillers grains with solubles (DDGS), pennycress (Thlaspi arvense L.) press cake (PPC), or lesquerella [Lesquerella fendleri (A. Gary) S. Watson] press cake (LPC) reinforced with Paulownia elongata L. wood (PW) particles. The goal in this study was to assess the mechanical properties of composites utilizing these low-cost matrix materials, which were subjected to various oil extraction methods. Three types of oil extraction methods were utilized: ethanol, supercritical CO2, and hexane, in order to generate matrix materials. These matrix materials were mixed with equal proportions of PW and hot pressed to generate panels. Overall, hexane extraction was the best method to enhance the mechanical properties of the matrices used to fabricate lignocellulosic composites. LPC’s produced a matrix that gave the resulting composite superior flexural properties compared to composites generated from DDGS and PPC matrices. The mechanical properties of composites generated from soy products (soybean meal flour or soy protein isolate) were similar to those derived from DDGS, PPC, or LPC. The dimensional stability properties of LCs were improved when the hexane extraction method was employed, unlike with the other extraction methods that were used to generate matrices. Full article
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Open AccessReview
Modelling and Design of Lanthanide Ion-Doped Chalcogenide Fiber Lasers: Progress towards the Practical Realization of the First MIR Chalcogenide Fiber Laser
Fibers 2018, 6(2), 25; https://doi.org/10.3390/fib6020025 -
Abstract
This paper presents the progress in the fields of the modelling and design of lanthanide ion-doped chalcogenide glass fiber lasers. It presents laser cavity designs that have been developed in order to optimize the performance of lanthanide ion-doped chalcogenide glass fiber lasers. Additionally,
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This paper presents the progress in the fields of the modelling and design of lanthanide ion-doped chalcogenide glass fiber lasers. It presents laser cavity designs that have been developed in order to optimize the performance of lanthanide ion-doped chalcogenide glass fiber lasers. Additionally, various numerical algorithms that have been applied for the optimization of chalcogenide glass lasers are reviewed and compared. The comparison shows that a combination of less accurate but more robust algorithms with more accurate ones gives the most promising performance. Full article
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