Showing papers on "Fiber published in 2010"
TL;DR: In this article, the role of microstructures on the fiber deformation behavior and present possible explanations for the enhanced properties of the nanofibers are discussed. But the authors focus on the techniques to obtain controlled structures and the mechanisms behind the size effect in electronspun fibers are given.
731 citations
TL;DR: In this paper, a detailed overview of stimulated Brillouin scattering (SBS) in single-mode optical fibers is presented, with a particular emphasis on analytical analysis of the backreflected power and SBS threshold in optical fibers with various index profiles.
Abstract: We present a detailed overview of stimulated Brillouin scattering (SBS) in
single-mode optical fibers. The review is divided into two parts. In the first part,
we discuss the fundamentals of SBS. A particular emphasis is given to analytical
calculation of the backreflected power and SBS threshold (SBST) in optical fibers
with various index profiles. For this, we consider acousto-optic interaction in the
guiding geometry and derive the modal overlap integral, which describes the
dependence of the Brillouin gain on the refractive index profile of the optical
fiber. We analyze Stokes backreflected power initiated by thermal phonons, compare
values of the SBST calculated from different approximations, and discuss the SBST
dependence on the fiber length. We also review an analytical approach to calculate
the gain of Brillouin fiber amplifiers (BFAs) in the regime of pump depletion. In the
high-gain regime, fiber loss is a nonnegligible effect and needs to be accounted for
along with the pump depletion. We provide an accurate analytic expression for the BFA
gain and show results of experimental validation. Finally, we review methods to
suppress SBS including index-controlled acoustic guiding or segmented fiber links.
The second part of the review deals with recent advances in fiber-optic applications
where SBS is a relevant effect. In particular, we discuss the impact of SBS on the
radio-over-fiber technology, enhancement of the SBS efficiency in Raman-pumped
fibers, slow light due to SBS and SBS-based optical delay lines, Brillouin
fiber-optic sensors, and SBS mitigation in high-power fiber lasers, as well as SBS in
multimode and microstructured fibers. A detailed derivation of evolutional equations
in the guided wave geometry as well as key physical relations are given in
appendices.
576 citations
TL;DR: This review summarizes the electrospinning techniques which control the composition and structures of the nanofibrous materials and outlines possible applications of these fibrous materials in skin, blood vessels, nervous system and bone tissue engineering, as well as in drug delivery.
445 citations
TL;DR: In this paper, Ramie fiber reinforced poly(lactic acid) (PLA) composites were prepared by a two-roll mill and Ramie was treated by alkali and silane (3-aminopropyltriethoxy silane and γ-glycidoxypropyltrimethoxysilane).
Abstract: Ramie fiber reinforced poly(lactic acid) (PLA) composites were prepared by a two-roll mill. Ramie was treated by alkali and silane (3-aminopropyltriethoxy silane and γ-glycidoxypropyltrimethoxy silane). Effect of surface treatment on the properties of the composites was studied. The tensile, flexural and impact strength of the composites have a significant improvement. Dynamic mechanical analysis (DMA) results show that the storage moduli of the composites with treated ramie increase with respect to the plain PLA and the composites with untreated fiber whereas tangent delta decreases. The Vicat softening temperature of the composites with treated fiber is greatly higher than that of the composites with untreated fiber. The results of thermogravimetric analysis (TGA) show that fiber treatment can improve the degradation temperature of the composites. Moreover, the morphology of fracture surface evaluated by scanning electron microscopy (SEM) indicates that surface treatment can get better adhesion between the fiber and the matrix.
404 citations
TL;DR: In this paper, a method to recycle wasted PET bottles is presented, in which short fibers made from recycled PET are used within structural concrete, and the results show that compressive strength and elastic modulus both decreased as fiber volume fraction increased.
Abstract: Most PET bottles used as beverage containers become waste after their usage, causing environmental problems. To address this issue, a method to recycle wasted PET bottles is presented, in which short fibers made from recycled PET are used within structural concrete. To verify the performance capacity of recycled PET fiber reinforced concrete, it was compared with that of polypropylene (PP) fiber reinforced concrete for fiber volume fractions of 0.5%, 0.75%, and 1.0%. Appropriate tests were performed to measure material properties such as compressive strength, elastic modulus, and restrained drying shrinkage strain. Flexural tests were performed to measure the strength and ductility capacities of reinforced concrete (RC) members cast with recycled PET fiber reinforced concrete. The results show that compressive strength and elastic modulus both decreased as fiber volume fraction increased. Cracking due to drying shrinkage was delayed in the PET fiber reinforced concrete specimens, compared to such cracking in non-reinforced specimens without fiber reinforcement (NF), which indicates crack controlling and bridging characteristics of the recycled PET fibers. Regarding structural member performance, ultimate strength and relative ductility of PET fiber reinforced RC beams are significantly larger than those of companion specimens without fiber reinforcement.
382 citations
TL;DR: In this paper, the effect of different fibers, mixing procedures and executive problems on asphalt concrete is inspected, where the authors focus on the first side of the coin and investigate FRAC materials modified by random fiber inclusion.
347 citations
TL;DR: In this article, a fiber-based Fabry-Perot cavity with CO2 laser-machined mirrors was realized, which combines very small size, high finesse, small waist and mode volume, and good mode matching between the fiber and cavity modes.
Abstract: We have realized a fiber-based Fabry–Perot cavity with CO2 laser-machined mirrors. It combines very small size, high finesse , small waist and mode volume, and good mode matching between the fiber and cavity modes. This combination of features is a major advance for cavity quantum electrodynamics (CQED), as shown in recent CQED experiments with Bose–Einstein condensates enabled by this cavity (Colombe Y et al 2007 Nature 450 272). It will also be suitable for a wide range of other applications, including coupling to solid-state emitters, gas detection at the single-particle level, fiber-coupled single-photon sources and high-resolution optical filters with large stopband.
342 citations
TL;DR: In this paper, the effect of these treatments on the structure, composition and properties of fibers was studied using SEM, FTIR, XPS, TGA and other analyses, showing that treatment with H2O2 is the most efficient in terms of waxy and fatty acid residues removal but it does not modify the surface chemical composition.
305 citations
TL;DR: The results from this investigation indicate that a 30 min dipping of the fibers in 0.5% alkali solution followed by 30 min alkali-steam treatment leads to an increase in the tensile strength of up to 65%, which appears to be due to fiber separation and removal of non-cellulosic materials, which, in turn, resulted in an increased crystallinity.
288 citations
TL;DR: In this paper, the authors evaluated the factors affecting the interfacial strength properties of polypropylene fiber (PP-fiber) reinforced soil by using a modified special apparatus and found that the designed pull-out test is an efficient method to qualitatively obtain the inter-surface peak strength (IPS) and interfacial residual strength (IRS) of fiber/soil.
288 citations
TL;DR: In this paper, the impact resistance and mechanical properties of steel fiber-reinforced concrete with water-cement ratios of 0.46 and 0.36, with and without the addition of silica fume.
TL;DR: Basalt and glass fibers were treated with sodium hydroxide and hydrochloric acid solutions respectively for different periods of time, and the mass loss ratio and the strength maintenance ratio of the fibers were examined after the treatment as discussed by the authors.
TL;DR: In this article, the authors explore an alternative approach to deliver CNTs to the fiber surface by dispersing carbon nanotubes in the fiber sizing formulation, which takes advantage of the developed techniques for CNT dispersion in resins and introduces no damage to the fibers.
TL;DR: Fiber diameter is an important parameter to consider when constructing aligned, electrospun fibers for nerve regeneration applications because in some situations, topography alone is sufficient to guide neurites without the leading support of SCs.
TL;DR: In this article, a number of experimental tests were conducted to investigate uniaxial compressive strength and tensile strength of steel fiber reinforced concrete (SFRC) and an analytical model was applied with the aim of making a comparison with experimental results.
Abstract: This paper deals with steel fiber reinforced concrete mechanical static behaviour and with its classification with respect to fibers content and mix-design variations. A number of experimental tests were conducted to investigate uniaxial compressive strength and tensile strength. Different mixtures were prepared varying both mix-design and fiber length. Fibers content in volume was of 1% and 2%. Mechanical characterization was performed by means of uniaxial compression tests with the aim of deriving the ultimate compressive strength of fiber concrete. Four-point bending tests on notched specimens were carried out to derive the first crack strength and the ductility indexes. The tensile strength of steel fiber reinforced concrete (SFRC) was obtained both from an experimental procedure and by using an analytical modelling. The experimental tests showed the different behaviour of SFRC with respect of the different fiber content and length. Based on the experimental results, an analytical model, reported in literature and used for the theoretical determination of direct tensile strength, was applied with the aim of making a comparison with experimental results. The comparison showed good overall agreement.
TL;DR: In this article, the effect of the carbonization temperature on surface chemistry, morphology, textural properties, and oxidation resistance of the final carbon fibers was studied, and it was shown that carbon fibers with and without platinum showed high oxidation resistance despite their highly developed porous structure.
TL;DR: In this article, the authors compared the performances of polylactic acid (PLA)/kenaf (PLA-K) and PLA/rice husk composites in terms of biodegradability, mechanical and thermal properties.
Abstract: This paper investigates and compares the performances of polylactic acid (PLA)/kenaf (PLA-K) and PLA/rice husk (PLA-RH) composites in terms of biodegradability, mechanical and thermal properties. Composites with natural fiber weight content of 20% with fiber sizes of less than 100 μm were produced for testing and characterization. A twin-screw extrusion was used to compound PLA and natural fibers, and extruded composites were injection molded to test samples. Flexural and Izod impact test, TGA, soil burial test and SEM were used to investigate properties. All results were compared to a pure PLA matrix sample. The flexural modulus of the PLA increased with the addition of natural fibers, while the flexural strength decreased. The highest impact strength (34 J m−1), flexural modulus (4.5 GPa) and flexural strength (90 MPa) were obtained for the composite made of PLA/kenaf (PLA-K), which means kenaf natural fibers are potential to be used as an alternative filler to enhance mechanical properties. On the other hand PLA-RH composite exhibits lower mechanical properties. The impact strength of PLA has decreased when filled with natural fibers; this decrease is more pronounced in the PLA-RH composite. In terms of thermal stability it has been found that the addition of natural fibers decreased the thermal stability of virgin PLA and the decrement was more prominent in the PLA-RH composite. Biodegradability of the composites slightly increased and reached 1.2 and 0.8% for PLA-K and PLA-RH respectively for a period of 90 days. SEM micrographs showed poor interfacial between the polymer matrix and natural fibers.
TL;DR: In this paper, the effect of fiber, matrix and interface properties on the in-plane shear response of carbon-fiber reinforced epoxy laminates was studied by means of a combination of experiments and numerical simulations.
TL;DR: A direct approach for fabricating nanoporous polymer fibers via electrospinning has been demonstrated and both the specific surface area and pore volume of the fibrous mats showed a unimodal distributions centered at 1/3 THF /DMF mix ratio.
Abstract: A direct approach for fabricating nanoporous polymer fibers via electrospinning has been demonstrated. Polystyrene (PS) fibers with micro- and nanoporous structures both in the core and/or on the fiber surfaces were electrospun in a single process by varying solvent compositions and solution concentrations of the PS solutions. The porous structures of the fibrous mats were characterized by field emission scanning electron microscopy and Brunauer−Emmett−Teller measurements to confirm that they could be accurately controlled by tuning vapor pressure of tetrahydrofuran (THF) and N,N-dimethylformamide (DMF) solvent mixtures and PS concentrations in the solutions. As the solution concentration decreased, the average fiber diameter decreased, whereas the bead density increased dramatically to show a beads-on-string morphology. Both the specific surface area and pore volume of the fibrous mats showed a unimodal distributions centered at 1/3 THF /DMF mix ratio. Fibers formed from 5 wt % PS in the 1/3 THF and DMF ...
TL;DR: In this article, a wheat bran dietary fiber (DF) powder was prepared by ultrafine grinding, whose effects on the composition, hydration and antioxidant properties of the DF products were investigated.
TL;DR: In this article, the authors performed uniaxial tensile tests on polyimide-supported copper films with a strong (1 1 1) fiber texture and with thickness varying from 50 nm to 1 μm.
TL;DR: In this paper, the basic characteristics and physical properties of kenaf ( Hibiscus cannabinus L.) fibers were analyzed using light microscopy (LM) and image analysis techniques.
TL;DR: New experimental data and an inventory of critical stimuli and state of activation of the signaling pathways involved in regulating contractile and metabolic protein turnover reveal higher capacity for protein synthesis in high compared to low oxidative fibers.
Abstract: An inverse relationship exists between striated muscle fiber size and its oxidative capacity. This relationship implies that muscle fibers, which are triggered to simultaneously increase their mass/strength (hypertrophy) and fatigue resistance (oxidative capacity), increase these properties (strength or fatigue resistance) to a lesser extent compared to fibers increasing either of these alone. Muscle fiber size and oxidative capacity are determined by the balance between myofibrillar protein synthesis, mitochondrial biosynthesis and degradation. New experimental data and an inventory of critical stimuli and state of activation of the signaling pathways involved in regulating contractile and metabolic protein turnover reveal: (1) higher capacity for protein synthesis in high compared to low oxidative fibers; (2) competition between signaling pathways for synthesis of myofibrillar proteins and proteins associated with oxidative metabolism; i.e., increased mitochondrial biogenesis via AMP-activated protein kinase attenuates the rate of protein synthesis; (3) relatively higher expression levels of E3-ligases and proteasome-mediated protein degradation in high oxidative fibers. These observations could explain the fiber type-fiber size paradox that despite the high capacity for protein synthesis in high oxidative fibers, these fibers remain relatively small. However, it remains challenging to understand the mechanisms by which contractile activity, mechanical loading, cellular energy status and cellular oxygen tension affect regulation of fiber size. Therefore, one needs to know the relative contribution of the signaling pathways to protein turnover in high and low oxidative fibers. The outcome and ideas presented are relevant to optimizing treatment and training in the fields of sports, cardiology, oncology, pulmonology and rehabilitation medicine.
TL;DR: In this article, the performance of glass/sisal hybrid composites focusing on mechanical (flexural and impact) and dynamic mechanical analyses (DMTA) was evaluated with different fiber loadings and different volume ratios between glass and sisal.
Abstract: This work aims to evaluate the performance of glass/sisal hybrid composites focusing on mechanical (flexural and impact) and dynamic mechanical analyses (DMTA). Hybrid composites with different fiber loadings and different volume ratios between glass and sisal were studied. The effect of the fiber length has also been investi- gated. The densities of the composites were compared with the theoretical values, showing agreement with the rule of mixtures. The results obtained in the flexural and impact analysis revealed that, in general, the properties were always higher for higher overall reinforcement content. By DMTA, an increase in the storage and loss modulus was found, as well as a shift to higher values for higher glass loading and overall fiber volume. It was also noticed an increase in the efficiency of the filler and the calculated acti- vation energy for the relaxation process in the glass transi- tion region. The fiber length did not significantly change the results observed in all analyses carried out in this work. The calculated adhesion factor increased for higher glass loadings, meaning the equation may not be applied for the system studied and there are other factors, besides adhe- sion influencing energy dissipation of the composites. V C 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 887-896, 2010
TL;DR: A novel graphene (G) based solid-phase microextraction (SPME) fiber was firstly prepared by immobilizing the synthesized G on stainless steel wire as coating and showed excellent thermal, chemical and mechanical stability, and long lifespan.
TL;DR: In this paper, the effects of high-temperature heat treatment on the microstructure and mechanical properties of the composites are studied, and it is found that mechanical properties can be greatly improved by densified and crystallized matrix, and the enhanced fiber/matrix interface bonding based on the fine-integrity of carbon fibers.
TL;DR: In this article, the effect of rigid straight fibers on the yield stress of cementitious materials is studied and a simple model describing the contact network between rigid fibers inside the material is first derived from the physical phenomena involved in the case of spherical inclusions.
TL;DR: In this paper, sisal fibers were mercerized, under tension and no tension, to improve their tensile properties and interfacial adhesion with soy protein resins, which is known to minimize fiber shrinkage and to lower the microfibrillar angle by aligning them along the fiber axis.
Abstract: Sisal fibers were mercerized, under tension and no tension, to improve their tensile properties and interfacial adhesion with soy protein resin. Mercerization of fibers under tension is known to minimize fiber shrinkage and to lower the microfibrillar angle by aligning them along the fiber axis. Mercerization improved the fracture stress and Young’s modulus of the sisal fibers while their fracture strain and toughness decreased. Mercerized sisal fiber-reinforced composites with soy protein resin showed improvement in both fracture stress and stiffness by 12.2% and 36.2%, respectively, compared to the unmercerized fiber-reinforced composites. Scanning electron microscope (SEM) photomicrographs of the composite fracture surfaces showed shorter fibrils protruding in the mercerized fiber-reinforced composites resulting in better sisal fiber/soy adhesion. Changed fiber surface properties were also responsible for better adhesion.
TL;DR: In this paper, a nanosilver particles-based antibacterial finish was used for the preparation of the silver nanoparticles colloid by making use of biomass filtrate of fungus Fusarium solani.
TL;DR: In this paper, the composition, morphology and properties of the four natural fibers were examined in order to select an appropriate fiber for manufacture of woven limited life geotextiles (LLGs).