Pour voir les autres types de publications sur ce sujet consultez le lien suivant : Fibred surface.
Articles de revues sur le sujet « Fibred surface »
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les 50 meilleurs articles de revues pour votre recherche sur le sujet « Fibred surface ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Parcourez les articles de revues sur diverses disciplines et organisez correctement votre bibliographie.
1
Lines, Daniel. « Stable Plumbing for High Odd-Dimensional Fibred Knots ». Canadian Mathematical Bulletin 30, no 4 (1 décembre 1987) : 429–35. http://dx.doi.org/10.4153/cmb-1987-063-4.
Texte intégralRésumé :
AbstractPlumbing a Hopf band on the fibre-surface of a simple fibred knot is a geometric operation that produces another such knot. We show by algebraic methods that every high odd-dimensional simple fibred knot is obtained from the unknot by using this operation and its inverse.
2
Serrano, Fernando. « The sheaf of relative differentials of a fibred surface ». Mathematical Proceedings of the Cambridge Philosophical Society 114, no 3 (novembre 1993) : 461–70. http://dx.doi.org/10.1017/s0305004100071759.
Texte intégralRésumé :
AbstractLet Φ: S → C denote a fibration from a smooth projective surface onto a smooth curve, with fibres of genus ≥2. The double dual of the sheaf of relative differentials has been studied by F. Serrano [14]. There, it was proved that dim grows asymptotically as the square of n in case Φ is not isotrivial (i.e. fibres vary in modulus), and the converse holds true in most cases, in a way that can be made precise. In the non-isotrivial case, the present paper provides further information about by analysing the linear systems for large n. If P denotes the positive part of in its Zariski decomposition, then it is shown that |rP| is eventually base-point free for some r > 0. Furthermore, Proj is a normal projective surface, fibred over C, birational to S, and with only rational singularities.
3
Barja, Miguel Ángel, et Francesco Zucconi. « On the slope of fibred surfaces ». Nagoya Mathematical Journal 164 (décembre 2001) : 103–31. http://dx.doi.org/10.1017/s0027763000008060.
Texte intégralRésumé :
We give an asymptotically sharp lower bound for the slope λ(f) of a fibration f : S → B, where S is a surface and B is a curve, if there exists an involution on the general fibre F of f. We also construct a new lower bound of λ(f) depending increasingly on the irregularity of S; as an application of this new bound we have a criteria to control the existence of other fibrations on S.
4
Catanese, Fabrizio, et Michael Dettweiler. « Vector bundles on curves coming from variation of Hodge structures ». International Journal of Mathematics 27, no 07 (juin 2016) : 1640001. http://dx.doi.org/10.1142/s0129167x16400012.
Texte intégralRésumé :
Fujita’s second theorem for Kähler fibre spaces over a curve asserts, that the direct image [Formula: see text] of the relative dualizing sheaf splits as the direct sum [Formula: see text], where [Formula: see text] is ample and [Formula: see text] is unitary flat. We focus on our negative answer [F. Catanese and M. Dettweiler, Answer to a question by Fujita on variation of Hodge structures, to appear in Adv. Stud. Pure Math.] to a question by Fujita: is [Formula: see text] semiample? We give here an infinite series of counterexamples using hypergeometric integrals and we give a simple argument to show that the monodromy representation is infinite. Our counterexamples are surfaces of general type with positive index, explicitly given as abelian coverings with group [Formula: see text] of a Del Pezzo surface [Formula: see text] of degree 5 (branched on the union of the lines of [Formula: see text], which form a bianticanonical divisor), and endowed with a semistable fibration with only three singular fibres. The simplest such surfaces are the three ball quotients considered in [I. C. Bauer and F. Catanese, A volume maximizing canonical surface in 3-space, Comment. Math. Helv. 83(1) (2008) 387–406.], fibred over a curve of genus 2, and with fibres of genus 4. These examples are a larger class than the ones corresponding to Shimura curves in the moduli space of Abelian varieties.
5
Leigh, Oliver. « UNWEIGHTED DONALDSON–THOMAS THEORY OF THE BANANA 3-FOLD WITH SECTION CLASSES ». Quarterly Journal of Mathematics 71, no 3 (8 juin 2020) : 867–942. http://dx.doi.org/10.1093/qmathj/haaa007.
Texte intégralRésumé :
Abstract We further the study of the Donaldson–Thomas theory of the banana 3-folds which were recently discovered and studied by Bryan [3]. These are smooth proper Calabi–Yau 3-folds which are fibred by Abelian surfaces such that the singular locus of a singular fibre is a non-normal toric curve known as a ‘banana configuration’. In [3], the Donaldson–Thomas partition function for the rank 3 sub-lattice generated by the banana configurations is calculated. In this article, we provide calculations with a view towards the rank 4 sub-lattice generated by a section and the banana configurations. We relate the findings to the Pandharipande–Thomas theory for a rational elliptic surface and present new Gopakumar–Vafa invariants for the banana 3-fold.
6
Scheyer, Torsten M., Elena V. Syromyatnikova et Igor G. Danilov. « Turtle shell bone and osteoderm histology of Mesozoic and Cenozoic stem-trionychian Adocidae and Nanhsiungchelyidae (Cryptodira : Adocusia) from Central Asia, Mongolia, and North America ». Fossil Record 20, no 1 (3 février 2017) : 69–85. http://dx.doi.org/10.5194/fr-20-69-2017.
Texte intégralRésumé :
Abstract. The record of fossil turtles from the Cretaceous and Cenozoic of Asia and North America is very rich, including several lineages of cryptodiran turtles. Here we survey the shell bone histology of two important closely related groups of stem trionychians, the Adocidae and Nanhsiungchelyidae, which have representatives in both Asia and North America. All studied taxa show shell bones in which the diploe is framed by well-developed cortical compact bone layers. Taxa of both groups also express external regular surface sculpturing of their shell bones, and in the case of the nanhsiungchelyid genus Basilemys also on the osteoderms, which is also reflected in the internal histological bone structures. Besides similarities of the regular ornamentation patterns, both groups share a number of microanatomical and histological characters such as the zonation of external cortex with rather homogeneous fine-fibred interwoven structural fibres (ISF) in the more internal zone and a dominance of vertically oriented fibres in the ISF and the presence of growth marks in the more external zone. On the other hand, growth marks, i.e. lines of arrested growth, which are visible as wavy lines in thin sections, extend subparallel to the external bone surface in adocids, but they are not parallel/subparallel in nanhsiungchelyids. Thickness and structure of bone trabeculae in the cancellous interior regions depends on the shell bone thickness of the individual samples. The internal cortices of all taxa except the North American samples of Adocus usually consist of parallel-fibred bone that locally grades into lamellar bone. Secondary bone remodelling is more frequent in nanhsiungchelyids compared to adocids, and Sharpey's fibres that extend perpendicular to the bone margins extending across subparallel growth marks are more commonly found in adocids. In addition, bone histology served to identify trionychid specimens in the adocid and nanhsiungchelyid samples, especially as bone surface sculpturing patterns were weathered or eroded in those cases. The histological data present thus supplement the numerous previously reported differences in external shell morphology between adocids and nanhsiungchelyids on the one hand and trionychids and carettochelyids on the other.
7
HILL, PETER, et KUNIO MURASUGI. « ON DOUBLE-TORUS KNOTS (II) ». Journal of Knot Theory and Its Ramifications 09, no 05 (août 2000) : 617–67. http://dx.doi.org/10.1142/s0218216500000359.
Texte intégralRésumé :
A double-torus knot is a knot embedded in a genus two Heegaard surface [Formula: see text] in S3. We consider double-torus knots L such that [Formula: see text] is connected, and consider fibred knots in various classes.
8
CAI, JIN-XING. « On Abelian automorphism groups of fibred surfaces of small genus ». Mathematical Proceedings of the Cambridge Philosophical Society 130, no 1 (janvier 2001) : 161–74. http://dx.doi.org/10.1017/s0305004100004758.
Texte intégralRésumé :
It is proved that, for a complex minimal smooth projective surface S of general type with a pencil of genus g = 3 or 4, any Abelian automorphism group of S is of order [les ] 12K2S + 96(g − 1), provided K2S > 8(g − 1)2, where KS is the canonical divisor of S.
9
Yu, Jing, Yumeng Tian, Zaiwen Lin, Qi Liu, Jingyuan Liu, Rongrong Chen, Hongsen Zhang et Jun Wang. « NiSe2/Ni5P4 nanosheets on nitrogen-doped carbon nano-fibred skeleton for efficient overall water splitting ». Colloids and Surfaces A : Physicochemical and Engineering Aspects 614 (avril 2021) : 126189. http://dx.doi.org/10.1016/j.colsurfa.2021.126189.
Texte intégral
10
Subramanya, Raghavendra, et S. S. Prabhakara. « Surface Modification of Banana Fiber and its Influence on Performance of Biodegradable Banana-Cassava Starch Composites ». Applied Mechanics and Materials 895 (novembre 2019) : 15–20. http://dx.doi.org/10.4028/www.scientific.net/amm.895.15.
Texte intégralRésumé :
Natural fibers, in particularly lignocellulosic fibers are attracting material scientists now days, due to their comparative advantages over synthetic fibers. Biodegradable composites reinforced with short banana fibre after alkali treatment along with cassava starch matrix were prepared using the hot compression method. The mechanical properties like tensile strength and impact strength were investigated. Mechanical properties of the composites made from alkali treated fibres were superior to the untreated fibres. SEM observations on the fracture surface of composites showed that the surface modification of the fibre occurred and improved fibre–matrix adhesion. Keywords: Surface modification; banana fiber; Biodegradable composites; Mechanical properties; Matrix.
11
Henkes, H., S. Brew, S. Felber, E. Miloslavski, G. Mogilevski, I. Tavrovski et D. Kühne. « In vitro and in vivo Studies of the Extent of Electrothrombotic Deposition of Blood Elements on the Surface of Electrolytically Detachable Coils ». Interventional Neuroradiology 10, no 3 (septembre 2004) : 189–201. http://dx.doi.org/10.1177/159101990401000301.
Texte intégralRésumé :
Endovascular treatment of intracranial aneurysms with electrolytically detachable coils is often claimed to be based on electrothrombosis, i.e. intra-aneurysmal thrombus formation through applied direct current. Despite the fact that this concept was described more than a century ago, the significance of electrothrombosis in the endovascular treatment of aneurysms remains debatable. Apart from electrothrombosis, mechanical obliteration of the aneurysmal lumen might be one of the many possible mechanisms to explain why and how detachable coils are effective in preventing aneurysms from (re-)rupture. The purpose of this experimental study was to investigate to what extent direct current comparable to that used for coil detachment would influence the adhesion of cellular and liquid blood components to the surface of electrolytically detachable platinum coils. For the in vitro study, electrolytically detachable platinum coils of various types were exposed to stagnant heparinised blood for a total of 16 h, without or with applied direct current for 30 or 90 s (1 mA, 4–6 V, coil as anode). For the in vivo study, electrolytically detachable platinum coils were exposed to flowing blood for 180 s, without or with applied direct current (2 mA, 4–6 V, coil as either anode or cathode), without anti-coagulation and after intravenous administration of 5000 U Heparin and again after the intravenous administration of 500 mg Aspisol in addition to Heparin. After exposure to blood according to these different experimental protocols, the coils were fixed in formalin solution, gold coated and examined by scanning electron microscopy. Thrombus formation on the surface of all unfibred coils was thin and highly variable both from coil to coil, and on different areas of any given coil. The application of direct current minimally enhanced thrombus formation in stagnant blood in vitro, but not in vivo. The cellular and fibrin adhesions on the coil surfaces without and with applied current did not effectively increase the diameter or volume of unfibred coils. Coils with attached nylon fibres, however, proved to be highly thrombogenic without or with application of current. In fibred coils, surface adhesions without and with applied current were voluminous enough to effectively increase the diameter of the coil, potentially important for the process of endosaccular aneurysm occlusion. Electrothrombosis plays no role in the endovascular treatment of intracranial aneurysms with electrolytically detachable coils. This explains why platinum coils with non-electrolytic detachment mechanisms show a similar efficiency and recurrence rate.
12
Webo, Wilson, Leonard Masu et Maina Maringa. « The Impact Toughness and Hardness of Treated and Untreated Sisal Fibre-Epoxy Resin Composites ». Advances in Materials Science and Engineering 2018 (1 août 2018) : 1–10. http://dx.doi.org/10.1155/2018/8234106.
Texte intégralRésumé :
The effect of the combined chemical treatment of sisal fibres through the subsequent processes of mercerisation (alkali treatment), then silane treatment and eventually acid hydrolysis, on sisal fibre was investigated. The effect of the treated fibres on the impact toughness and hardness of their composites with epoxy resin was also studied. Scanning electron microscopy of the surfaces of the treated and untreated fibres showed that the chemical treatment processes enhanced the removal of surface impurities and therefore increased the roughness of the surfaces of the fibres. This avails an increased surface area for interlocking with matrix and is, therefore, expected to enhance adhesion of the two. The treated fibre reinforced composites were observed to have higher values of impact toughness and hardness than the untreated fibre reinforced composites. These higher values were attributed to better interfacial bonding due to better mechanical interlocking between the treated fibres and epoxy resin arising from the increased roughness of the treated fibres.
13
Xu, Pei Pei, Xin Fu Wang, Shun De Fu et Jian Feng Xu. « Preparation of Zirconia-Yttrium Fibres from Steady Precursor by Sol-Gel Technique ». Advanced Materials Research 535-537 (juin 2012) : 2087–91. http://dx.doi.org/10.4028/www.scientific.net/amr.535-537.2087.
Texte intégralRésumé :
Polycrystalline tetragonal Y-ZrO2 fibres were fabricated via sol-gel technique by the centrifugal filament method using zirconium oxychloride octahydrate as the raw material. The spinnable zirconia sol was obtained by concentrating the solution, which the molar ratios of H2O2/ZOC and HA/ZOC were 3.0 and 0.5-1.0, respectively. FT-IR, TG/DTA, XRD and SEM were used to characterize the chemical composition and morphology of zirconia fibres. The bridging bidentate coordination between the carboxyl group and zirconium polymer can promote the spinnability of sols. The polycrystalline zirconia fibres structures are metastable tetragonal phase after heat treatment at 1200°C in 1h. The distribution of fibres is not uniform with a diameter from 5 μm to 10 μm. The single fibre has a uniform diameter and smooth surface, without any defect on the surfaces. The grain size of ZrO2 fibers increases with the heat treatment temperature gradually.
14
Webo, Wilson, Maina Maringa et Leonard Masu. « The Combined Effect of Mercerisation, Silane Treatment and Acid Hydrolysis on the Mechanical Properties of Sisal Fibre/Epoxy Resin Composites ». MRS Advances 5, no 23-24 (2020) : 1225–33. http://dx.doi.org/10.1557/adv.2020.122.
Texte intégralRésumé :
ABSTRACTThe effect of the combined chemical treatment of sisal fibres through the subsequent processes of mercerisation (alkali-treatment), then silane treatment and eventually acid hydrolysis, on sisal fibre were investigated. The effect of the treated fibres on the tensile strength and stiffness, flexural strength and stiffness, compression strength and shear strength of their composites with epoxy resin were also studied. Scanning electron microscopy studies of the surfaces of the treated and untreated fibres showed that the chemical treatment processes enhanced the removal of surface extractives and therefore increased the roughness of the surfaces of the fibres in the range of 20 % - 70 %. This avails an increased reinforcement surface area for interlocking with matrix and is, therefore, expected to enhance adhesion of the two. The treated fibre reinforced composites were observed to have higher values of tensile strength and stiffness, flexural strength and stiffness, compression strength and shear strength than the un-treated fibre reinforced composites. These higher values were attributed to better interfacial bonding due to better mechanical interlocking between the treated fibres and epoxy resin arising from the increased roughness of the treated fibres.
15
Schönberg, C., T. Oksanen, A. Suurnäkki, H. Kettunen et J. Buchert. « The Importance of Xylan for the Strength Properties of Spruce Kraft Pulp Fibres ». Holzforschung 55, no 6 (6 novembre 2001) : 639–44. http://dx.doi.org/10.1515/hf.2001.104.
Texte intégralRésumé :
Summary In this work the role of xylan in spruce kraft pulp fibres was investigated by selectively removing the pulp fibre xylan and also by sorbing xylan onto the pulp fibres. The effects of xylan removal and sorption on fibre properties were measured and the chemical composition of the fibres and also that of the selectively removed xylans was analyzed. According to the results the xylanase could act on both sorbed and native xylan located on accessible fibre surfaces. Xylan was found to affect the strength properties of handsheets. The location and the charge of xylan had a considerable impact on the formation of interfibre bonds. Scott Bond-values correlated with the amount of surface xylan on fibre surfaces, whereas tensile strength was affected by the total amount of xylan and particularly by the total charge of the fibres. The fracture energy was determined by the combined effect of interfibre bonding ability and effective fibre length.
16
Zhang, C. H., Y. D. Huang et L. Liu. « Surface Modification of PBO Fibres by Gamma-Ray Irradiation : Effects on Interfacial Properties of their Epoxy Composites ». Polymers and Polymer Composites 13, no 3 (mars 2005) : 263–70. http://dx.doi.org/10.1177/096739110501300306.
Texte intégralRésumé :
The surfaces of poly [p-phenylene benzobisoxazole] (PBO) fibres were grafted with epichlorohydrin by a gamma (γ)-ray irradiation method. The influence of irrdiation dose on the interfacial shear strength (IFSS), interlaminar shear strength (ILSS) and the fibre wettability were investigated. In addition, the fibre surface composition, and the shear fracture topography of PBO fibre/epoxy resin composites were analysed by X–ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), respectively. The results indicate that a dose of 30KGy was the optimal condition for PBO fibre surface modification. The oxygen content of the irradiated PBO fibres was 22% higher than that of the untreated ones, and chlorine atoms were introduced onto the surface of the fibres through grafting actions between epichlorohydrin and PBO. The wettability of the epichlorohydrin-grafted PBO fibres was significantly increased, and the values of IFSS and ILSS of its composites were increased by 70% and 135%, respectively. SEM shows that the improved interfacial adhesion resulted in a change in the failure mode of PBO fibre/epoxy composite from an adhesive-type interfacial failure to a cohesive-like matrix failure.
17
Lublóy, Éva. « The Influence of Concrete Strength on the Effect of Synthetic Fibres on Fire Resistance ». Periodica Polytechnica Civil Engineering 62, no 1 (23 juin 2017) : 136–42. http://dx.doi.org/10.3311/ppci.10775.
Texte intégralRésumé :
Numerous studies have verified that increased concrete strength reduces its resistance to fire, leads to a higher degree of strength reduction and higher chances of spalling of concrete surfaces.The risks of spalling of concrete surfaces can be reduced by adding synthetic polypropylene fibres. Numerous experiments have shown that the risk of spalling of the concrete surface is significantly lower when using short, small diameter fibres of polypropylene synthetic, because the pore structure created by the burning of fibres reduces the risk of cracking.However, the question arises whether other types of fibres of greater diameter and length are still able to prevent spalling of concrete surfaces without drastically reducing the strength and if so, in what range of concrete strength it is true.The experiments are aimed to determine the effects of micro and macro synthetic fibres on the post-fire residual compressive strength, flexural strength and porosity of concrete.Nine kinds of mixture were prepared and tested. Three of them are without fibers (reference concretes) with diverse strength, three with synthetic micro-fibres with diverse strength and three with synthetic macro-fibres of diverse strength. The experiment was conducted with three concretes with different strength. Each type had a reference concrete without fibre reinforcement, one with micro- and one with macro-fibres.
18
Sinha, Agnivesh Kumar, Harendra Kumar Narang et Somnath Bhattacharya. « Experimental Investigation of Surface Modified Abaca Fibre ». Materials Science Forum 978 (février 2020) : 291–95. http://dx.doi.org/10.4028/www.scientific.net/msf.978.291.
Texte intégralRésumé :
Natural fibres have gained popularity due to their use in fabrication of biodegradable polymer composites which are not only non-polluting but are also light weight and inexpensive. Abaca fibres are known for their remarkable properties for which their polymer composites are used in automotive applications. However, hydrophilicity and compatibility with polymer matrices are the two major drawbacks of natural fibres which restrict their use as reinforcements in polymer composites. Therefore, present study deals with the surface modifications of abaca fibre using potassium permanganate and sodium hydroxide solutions to enhance crystallinity and reduce hydrophilicity of abaca fibres. Further, the surfaces of untreated and treated fibre were investigated with the help of Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis. Surface treatment of abaca fibre led to the removal of unwanted wax, and other amorphous materials which was confirmed through FTIR analysis. Crystallinity index was found to be 57%, 59% and 61% for untreated, NaOH treated and KMnO4 treated abaca fibre respectively.
19
CHAKRAVARTHY, SRINATH S., et WILSON K. S. CHIU. « Boundary integral method for the evolution of slender viscous fibres containing holes in the cross-section ». Journal of Fluid Mechanics 621 (12 février 2009) : 155–82. http://dx.doi.org/10.1017/s0022112008004783.
Texte intégralRésumé :
We consider the evolution of slender viscous fibres with cross-section containing holes with application to fabrication of microstructured optical fibres. The fibre evolution is driven by either prescribing velocity or a force at the ends of the fibre, and the free surfaces evolve under the influence of surface tension, internal pressurization, inertia and gravity. We use the fact that ratio of the typical fibre radius to the typical fibre length is small to perform an asymptotic analysis of the full three-dimensional Navier–Stokes equations similar to earlier work on non-axisymmetric (but simply connected) fibres. A numerical solution to the multiply connected steady-state drawing problem is formulated based on the solution the Sherman–Lauricella equation. The effects of different drawing and material parameters like surface tension, gravity, inertia and internal pressurization on the drawing are examined, and extension of the method to non-isothermal evolution is presented.
20
Li, Hui, Yan Fei Zhang, Ya Qing Liu, Gui Zhe Zhao et Rui Kui Du. « Study on Preparation and Properties of Ramie Fiber Reinforced Composites ». Advanced Materials Research 712-715 (juin 2013) : 203–7. http://dx.doi.org/10.4028/www.scientific.net/amr.712-715.203.
Texte intégralRésumé :
Ramie fibres were surface treated in order to enhance the interfacial interaction between ramie natural fibres and vinyl resin matrix. The fibres are exposed to three different treatment ways in this paper. The surface topography and binding force influenced by the treatments were characterized by contact angle and mechanical property. Single fibre pull-out tests combined with SEM characterization of the fracture surfaces were used to identify the interfacial strengths and to reveal the mechanisms of failure.
21
Chegdani, Faissal, Sabeur Mezghani et Mohamed El Mansori. « Correlation between mechanical scales and analysis scales of topographic signals under milling process of natural fibre composites ». Journal of Composite Materials 51, no 19 (13 novembre 2016) : 2743–56. http://dx.doi.org/10.1177/0021998316676625.
Texte intégralRésumé :
This article aims to find the relation between the multiscale mechanical structure of natural fibre reinforced plastic composites and the analysis scales in the topographic signals of machined surfaces as induced by profile milling process. Bamboo, sisal and miscanthus fibres reinforced polypropylene composites were considered in this study. The multiscale process signature of natural fibre reinforced plastic machined surfaces based on wavelet decomposition was determined. Then, the impact of wavelet function was inspected by testing different wavelet shapes. Finally, the analysis of variance was carried out to exhibit the contribution rate of fibre stiffness and tool feed on the machined surface roughness at each analysis scale. Results demonstrate that studying the machining of natural fibre reinforced plastic requires the selection of the relevant scales. They show also the insignificance of the wavelet choice. This study proves that the contribution rate of fibre stiffness and tool feed on machined surface roughness is significantly dependent on the analysis scales, which are directly related to the mechanical properties of natural fibres structure inside the composite.
22
Brodowsky, Hanna M., Anne Hennig, Michael Thomas Müller, Anett Werner, Serge Zhandarov et Uwe Gohs. « Laccase-Enzyme Treated Flax Fibre for Use in Natural Fibre Epoxy Composites ». Materials 13, no 20 (13 octobre 2020) : 4529. http://dx.doi.org/10.3390/ma13204529.
Texte intégralRésumé :
Natural fibres have a high potential as reinforcement of polymer matrices, as they combine a high specific strength and modulus with sustainable production and reasonable prices. Modifying the fibre surface is a common method to increase the adhesion and thereby enhance the mechanical properties of composites. In this study, a novel sustainable surface treatment is presented: the fungal enzyme laccase was utilised with the aim of covalently binding the coupling agent dopamine to flax fibre surfaces. The goal is to improve the interfacial strength towards an epoxy matrix. SEM and AFM micrographs showed that the modification changes the surface morphology, indicating a deposition of dopamine on the surface. Fibre tensile tests, which were performed to check whether the fibre structure was damaged during the treatment, showed that no decrease in tensile strength or modulus occurred. Single fibre pullout tests showed a 30% increase in interfacial shear strength (IFSS) due to the laccase-mediated bonding of the coupling agent dopamine. These results demonstrate that a laccase + dopamine treatment modifies flax fibres sustainably and increases the interfacial strength towards epoxy.
23
Yang, Zhi Yuan, Hai Zhen Shi et Yan Jun Tang. « Changes in Layer Properties and Physical Properties of Papers from Old Corrugated Container Fibres with PDADMAC/HEC Polyelectrolyte Multilayers ». Advanced Materials Research 496 (mars 2012) : 67–70. http://dx.doi.org/10.4028/www.scientific.net/amr.496.67.
Texte intégralRésumé :
In this paper, Old Corrugated Container (OCC) was used as the raw material for making paper. The layer-by-layer (LBL) assembly process of creating highly structured thin films was adopted to modify the surface of OCC fibres. Poly dimethyldiallylammonium chloride (PDADMAC) and hydroxyethyl cellulose (HEC) have been used to build up polyelectrolyte multilayers on OCC fibres under a certain condition. Zeta potential analyzer was used to monitor the dynamic adsorption of PDADMAC and HEC with different amount on OCC fibers. Strength measurements of the sheets including tensile index and bursting index were also determined, showing a significant improvement in physical strength with the increase of adsorbed layer number. Compared with not being processed sheets, tensile index and bursting index of sheets from treated fibre with polyelectrolyte multilayers were raised by 36.65% and 49.50%, respectively. Furthermore, filtration time analysis of OCC fibre suspension showed that the built up of PDADMAC and HEC on OCC fibres could improve the fiber-fiber joint strength of joints from polymer-treated fibers, which made the filtration time decline from 30 s to 10.6 s. In addition, SEM was introduced to observe the morphology of the PDADMAC/HEC multilayers. The images revealed that the surface of OCC fibres structured a film like plastic, which could be ascribed to the adsorption layer of polyelectrolyte.
24
Gonzalez, C., et J. Llorca. « Mechanical Properties of Sigma 1140+ Sic Fibres Prior and after Composite Processing ». Advanced Composites Letters 9, no 4 (juillet 2000) : 096369350000900. http://dx.doi.org/10.1177/096369350000900406.
Texte intégralRésumé :
The effect of processing on the mechanical properties of Sigma 1140+ SiC fibres was studied through tensile tests carried out on pristine Sigma 1140+ SiC fibres and on fibres extracted from a Ti-6A1-4V-matrix composite. The elastic modulus and the tensile strength were computed after measuring carefully the fibre diameter. The characteristic fibre strength was reduced by 20% and the Weibull modulus by half during composite processing. The analysis of the fracture surfaces in the scanning electron microscope showed that the strength-limiting defects were located around the tungsten core in pristine fibres and predominantly at the surface in fibres extracted from the composite panels. These latter defects were nucleated by the mechanical stresses generated on the fibres during the panel consolidation.
25
Kamps, Jan Henk, Luke Henderson, Christina Scheffler, Ruud van der Heijden, Frank Simon, Teena Bonizzi et Nikhil Verghese. « Electrolytic Surface Treatment for Improved Adhesion between Carbon Fibre and Polycarbonate ». Materials 11, no 11 (12 novembre 2018) : 2253. http://dx.doi.org/10.3390/ma11112253.
Texte intégralRésumé :
To achieve good mechanical properties of carbon fibre-reinforced polycarbonate composites, the fibre-matrix adhesion must be dialled to an optimum level. The electrolytic surface treatment of carbon fibres during their production is one of the possible means of adapting the surface characteristics of the fibres. The production of a range of tailored fibres with varying surface treatments (adjusting the current, potential, and conductivity) was followed by contact angle, inverse gas chromatography and X-ray photoelectron spectroscopy measurements, which revealed a significant increase in polarity and hydroxyl, carboxyl, and nitrile groups on the fibre surface. Accordingly, an increase in the fibre-matrix interaction indicated by a higher interfacial shear strength was observed with the single fibre pull-out force-displacement curves. The statistical analysis identified the correlation between the process settings, fibre surface characteristics, and the performance of the fibres during single fibre pull-out testing.
26
Pipathattakul, Manop, Prayoon Surin et Jessada Wongon. « Surface Modification of Sisal Fibres by Ultrasonic Field ». Key Engineering Materials 728 (janvier 2017) : 283–88. http://dx.doi.org/10.4028/www.scientific.net/kem.728.283.
Texte intégralRésumé :
This article demonstrates the surface modification of sisal fibres by using NaOH in an ultrasonic medium. The fibres were soaked in 1.0 M NaOH, 60°C for 30, 60, and 90 min, respectively. The fibre surface was examined with a digital microscope camera and a scanning electron microscope (SEM). An elasticity test was used to examine the mechanical properties of composites, specifically between sisal and LLDPE. The results demonstrated the modification of the sisal fibres in NaOH solution by ultrasound producing a cleaner and smoother fibre surface. This was affected by a cavitation phenomenon, which produced high-speed impact jets that cleaned off the dirty particles from the fibre surface. The modified mixed materials had higher ultimate tensile strength. By using this method, the result of sisal fibre modification decreased in the diameter strand of the experimented fibres.
27
Paiva, M. C., Anissa El Gaied, R. Ben Cheikh et António M. Cunha. « Interfaces in Alfa Fibre-Polypropylene Matrix Composites ». Materials Science Forum 587-588 (juin 2008) : 227–31. http://dx.doi.org/10.4028/www.scientific.net/msf.587-588.227.
Texte intégralRésumé :
Model composites with Polypropylene (PP) as matrix and alfa fibres (cellulose-based fibres obtained from the esparto grass of the subsaarian dry regions of Tunisia) were prepared for fibre/matrix interfacial characterization studies. The matrices tested were PP and PP combined with PP modified with maleic anhydride (PP-g-MA). The surface of the alfa fibres was treated by air plasma treatment. The adhesion between the untreated and treated fibres and both matrices was studied using the fragmentation test method. Composites with 10% weight of fibres were prepared by melt extrusion and injection moulding, and the specimens obtained tested for tensile properties. The fracture surfaces of the composites, obtained at low temperature, were observed by scanning electron microscopy. The presence of a small concentration of maleic anhydride grafted to the polymer matrix was found to be of the utmost importance for the establishment of a good fibre/matrix interface. The air plasma treatment had a cleaning effect of the fibre’s surface.
28
Leman, Zulkiflle, S. M. Sapuan et S. Suppiah. « Sugar Palm Fibre-Reinforced Unsaturated Polyester Composite Interface Characterisation by Pull-Out Test ». Key Engineering Materials 471-472 (février 2011) : 1034–39. http://dx.doi.org/10.4028/www.scientific.net/kem.471-472.1034.
Texte intégralRésumé :
Polymer composites using natural fibres as the reinforcing agents have found their use in many applications. However, they do suffer from a few limitations, due to the hydrophilicity of the natural fibres which results in low compatibility with the hydrophobic polymer matrices. This paper aims to determine the best sugar palm (Arenga pinnata) fibre surface treatment to improve the fibre-matrix interfacial adhesion. Fibre surface modifications were carried out by water retting process where the fibres were immersed in sea water, pond water and sewage water for the period of 30 days. The test samples were fabricated by placing a single fibre in an unsaturated polyester resin. Single-fibre pull-out tests showed that freshwater-treated fibres possessed the highest interfacial shear strength, followed by untreated fibres, sewage water-treated fibres, and sea water-treated fibres. Further surface analyses of the samples were performed using a Scanning Electron Microscope (SEM) and an Energy Dispersive X-ray Spectroscopy (EDS) system.
29
Jenkins, Peter, Liu Yang et James Thomason. « Investigation of Atmospheric Moisture during Heat Treatment of Glass Fibres ». Fibers 7, no 4 (1 avril 2019) : 27. http://dx.doi.org/10.3390/fib7040027.
Texte intégralRésumé :
The tensile strength of single water-sized E-glass fibres that were thermally conditioned, either in air or under vacuum, was investigated. The vacuum removed water from the conditioning atmosphere, as well as the fibre surfaces, at room temperature but retained tensile strength of fibres treated in the absence of water were not significantly different from those thermally conditioned in a standard air furnace. The results suggest that water, either in the treatment atmosphere or on the surface of the fibres, is not a significant factor in fundamental glass fibre strength loss at an elevated temperature. It may, therefore, be necessary to consider alternative theories to explain this strength loss.
30
Wilkes, John. « Effect of Moisture Content on the Morphology of Longitudinal Fracture in Eucalyptus Maculata ». IAWA Journal 8, no 2 (1987) : 175–81. http://dx.doi.org/10.1163/22941932-90001044.
Texte intégralRésumé :
The longitudinal surfaces of Eucalyptus maculata wood sampies fractured either artificially (splitting) or naturally (drying stresses) at a range of moisture contents, were examined under a scanning eleetron microscope. In those sam pies above fibre saturation point, a relativeIy clean surface was produced, since the cells either separated in the outer regions of the wall with minimal fibrillation (fibres, some ray parenchyma), or the fracture path travelled abruptly through the wall exposing the lumen (vertical parenchyma, vessels, so me ray cells). Below fibre saturation, particularly as the air dry condition was approached, a fibrous, splintery surface resulted, due mainly to fibrillation and delamination of the secondary walls in fibres and ray parenchyma.
31
Liu, Xiaoling, David M. Grant, Andrew J. Parsons, Lee T. Harper, Chris D. Rudd et Ifty Ahmed. « Magnesium Coated Bioresorbable Phosphate Glass Fibres : Investigation of the Interface between Fibre and Polyester Matrices ». BioMed Research International 2013 (2013) : 1–10. http://dx.doi.org/10.1155/2013/735981.
Texte intégralRésumé :
Bioresorbable phosphate glass fibre reinforced polyester composites have been investigated as replacement for some traditional metallic orthopaedic implants, such as bone fracture fixation plates. However, composites tested revealed loss of the interfacial integrity after immersion within aqueous media which resulted in rapid loss of mechanical properties. Physical modification of fibres to change fibre surface morphology has been shown to be an effective method to improve fibre and matrix adhesion in composites. In this study, biodegradable magnesium which would gradually degrade to Mg2+in the human body was deposited via magnetron sputtering onto bioresorbable phosphate glass fibres to obtain roughened fibre surfaces. Fibre surface morphology after coating was observed using scanning electron microscope (SEM). The roughness profile and crystalline texture of the coatings were determined via atomic force microscope (AFM) and X-ray diffraction (XRD) analysis, respectively. The roughness of the coatings was seen to increase from40±1 nm to80±1 nm. The mechanical properties (tensile strength and modulus) of fibre with coatings decreased with increased magnesium coating thickness.
32
Henriksson, Åsa, et Paul Gatenholm. « Controlled Assembly of Glucuronoxylans onto Cellulose Fibres ». Holzforschung 55, no 5 (19 septembre 2001) : 494–502. http://dx.doi.org/10.1515/hf.2001.081.
Texte intégralRésumé :
Summary In this study we have shown that cellulose fibres can be coated with regular micron-sized particles by controlling the assembly process of xylans on the cellulose surfaces. When cotton linters were exposed to a 5% water solution of xylan from birchwood at 110°C, 2 h, pH 8, the substrates showed an increase in weight of approximately 6.5%, and visualization by AFM revealed regular particles on the fibre surfaces. The surface modification process was optimized using an experimental design where time, temperature, and pH were varied. The experiments showed that the amount of xylan deposited on the fibres could be varied from 2% up to 20% depending on treatment conditions. The temperature and time were the most important parameters, while pH was not important in the investigated region. The morphology of the deposited xylan layer, as shown by SEM, was dependent on the amount of xylan on the fibre surfaces. At low yield the fibres were coated with a homogenous layer, while at higher yields (20%) regular particles of micron size were identified by AFM analysis. The mechanism of this assembly process of xylan on cellulose fibre surfaces is discussed.
33
Miller, Hugh D., Ali Akbarnezhad, Sara Mesgari et Stephen J. Foster. « Effects of silane treatment on the bond between steel fibres and mortar ». Magazine of Concrete Research 74, no 10 (mai 2022) : 528–40. http://dx.doi.org/10.1680/jmacr.20.00366.
Texte intégralRésumé :
The ability of fibres to resist crack growth in fibre-reinforced concrete can be significantly influenced by the fibre–matrix bond. This investigation reveals surface treatment of fibres as a viable technique for developing a uniform bond along the fibre–cement interface to resist growth of microcracks and thereby complement the physical restraint against pull-out provided by fibres’ shape and friction. Previous reports have shown effective chemical treatment of glass, carbon and polypropylene fibres. However, research into chemical surface treatment processes for steel fibres, the most common in concrete, is scarce and focused on corrosion and dispersion, rather than the fibre–matrix bond. Here, a silane treatment technique is proposed to strengthen the steel fibre–cementitious matrix bond. Surface energy measurements and X-ray photoelectron spectroscopy demonstrate the effectiveness of this treatment. Fibre pull-out tests conducted on silane-treated fibres show an apparent increase in pull-out energy, accompanied by a delay in reaching the peak load, compared with untreated fibres, suggesting increased resistance to crack initiation and growth. Furthermore, the results indicate improved flexural strength and direct tensile strength of mortar reinforced with silane-treated fibres compared with untreated fibres. The improvements are further corroborated by results from restrained drying shrinkage and volume of permeable voids.
34
Liu, J., Shang Lin Gao, Edith Mäder, A. D. Bianchi, Thilo Herrmannsdörfer, S. Zherlitsyn, B. S. A. Zvyagin et J. Wosnitza. « Adhesion Issues in PBO/Epoxy Composites ». Key Engineering Materials 334-335 (mars 2007) : 233–36. http://dx.doi.org/10.4028/www.scientific.net/kem.334-335.233.
Texte intégralRésumé :
The high performance of poly p-phenylene-2,6-benzobisoxazole (PBO) fibre in mechanical properties and environmental resistance provides great potential applications as reinforcement fibres for composites. However, poor adhesion between PBO fibre and matrix is found because of the chemically inactive and/or relatively smooth surface of the reinforcement fibre. Here, we report the surface modification of PBO fibres by O2 and NH3 plasma treatments. The surface energy and roughness are increased for both sized and extracted fibres after plasma treatments. The sized fibre shows marginal improvement in interfacial adhesion and no change in fibre tensile strength because of the barrier effect of the sizing layer. For the extracted fibre, the plasma treatments cause reduction in both interfacial adhesion and the tensile strength, which is sensitive to plasma treatment conditions as revealed by a bimodal Weibull statistical distribution analysis. The fibre surface roughness is increased and more surface flaws are induced, which could result in coarse interface structures when the treated fibre surface has no adequate wetting and functional groups.
35
Li, J. « Interfacial features of polyamide 6 composites filled with oxidation modified carbon fibres ». Proceedings of the Institution of Mechanical Engineers, Part C : Journal of Mechanical Engineering Science 223, no 9 (22 mai 2009) : 2135–41. http://dx.doi.org/10.1243/09544062jmes1402.
Texte intégralRésumé :
Polyacrylonitrile (PAN)-based carbon fibres were surface treated by ozone modification method and air-oxidation treatment. The interfacial properties of carbon fibre reinforced polyamide 6 (CF/PA6) composites were investigated by means of the single fibre pull-out tests. The surface characteristics of carbon fibres were characterized by X-ray photoelectron spectroscopy (XPS). As a result, it was found that interfacial shear strength values of the composites with ozone-treated carbon fibre are greatly increased. XPS results show that ozone treatment increases the amount of carboxyl groups on the carbon fibre surface, thus the interfacial adhesion between carbon fibre and PA6 matrix is effectively promoted. The effect of surface treatment of carbon fibres on the tribological properties of CF/PA6 composites was comparatively investigated. Experimental results revealed that surface treatment can effectively improve the interfacial adhesion between carbon fibre and PA6 matrix. Thus the wear resistance was significantly improved.
36
Anuar, Atikah, Mohd Rozi Ahmad et Mohamad Faizul Yahya. « Linear Density and Surface Morphology of Kenaf Fibres from Different Extraction Methods ». Advanced Materials Research 1134 (décembre 2015) : 103–8. http://dx.doi.org/10.4028/www.scientific.net/amr.1134.103.
Texte intégralRésumé :
The fineness and morphology of kenaf fibres are the main focus of this paper. The kenaf fibres were processed through water retting, chemical retting and mechanical extractions. The water retting method produces finer fibres between 3.2 to 3.7 Tex while other methods produces fibres between 4.0 to 5.0 Tex. The chemical retting method resulted in smoother fibre surface when examined using Field Emission Scanning Electron Microscopy under different magnifications. The fibre diameters from the different retting and extraction methods vary from 33 to 134 m and did not show to have any relationship with fibre fineness.
37
Greco, Antonio, Alfonso Maffezzoli, Giuseppe Buccoliero, Flavio Caretto et Giacinto Cornacchia. « Thermal and chemical treatments of recycled carbon fibres for improved adhesion to polymeric matrix ». Journal of Composite Materials 47, no 3 (22 mars 2012) : 369–77. http://dx.doi.org/10.1177/0021998312440133.
Texte intégralRésumé :
The aim of this study is the characterization of recycled carbon fibres, in view of their potential application in long-fibre reinforced thermoplastic composite. The fibres were obtained from epoxy matrix composite panels, applying a patented process that includes the pyrolisis of the matrix followed by an upgrading of the fibres. Then, recycled fibres were further subjected to thermal and acid treatments in order to modify their surface morphology and chemistry. Scanning electron microscopy and energy dispersive spectrometry were used to characterize the morphological and compositional changes of the fibre surface. The fibres were characterized in terms of mechanical properties and adhesion to an epoxy matrix. The fibres treated by thermal processes at high temperatures (600°C) were shown to be too severely damaged, making them unsuitable for the production of fibre-reinforced composites. A thermal treatment at lower temperatures (450°C) involved a very limited damaging without any evident chemical modification of the fibre surface, which in turn involved a limited increase of the adhesion properties to an epoxy matrix. Chemical treatment by nitric acid caused a very limited damage of fibres, coupled with a significant modification of surface chemistry, which in turn involved a further increase of the fibre/matrix adhesion properties.
38
Zhao, Guozhen, Jianhua Liu, Lei Xu et Shenghui Guo. « Comparative study of conventional and microwave heating of polyacrylonitrile-based fibres ». Journal of Polymer Engineering 41, no 3 (2 février 2021) : 175–83. http://dx.doi.org/10.1515/polyeng-2020-0167.
Texte intégralRésumé :
Abstract The effects of the conventional heating method and the microwave heating method on polyacrylonitrile-based fibres in the temperature range of 180–280 °C were investigated. Fourier transform infrared spectroscopy, X-ray wide-angle scattering, Raman spectroscopy, energy-dispersive spectrometer, scanning electron microscopy and bulk density were used to characterise the properties of the samples. Results show that the microwave heating method can shorten the pre-oxidation time, reduce pre-oxidation temperature and reduce the number of surface defects. The pre-oxidised fibres obtained by the microwave heating method exhibit not only good crystallite size but also a smooth surface. Atomic morphology and molecular arrangement are orderly inside the fibre. The FT-IR spectrum shows that the oxidation reaction occurs at 220 °C, and the CI value of PAN fibers stabilised by microwave heating is the larger than the fibers stabilised by conventional heating. XRD analysis shows that fibers stabilised by microwave heating have low stack domains. The SEM and Raman spectra indicate that hydrogen peroxide can improve the surface finish of the fibers and reduce defects. Microwave heating can reduce the pre-oxidation temperature by about 20 °C and shorten the heating time. The economic benefits of using this method are significantly improved.
39
Mwonga, Michael M., Charles Kabubo et Naftary Gathimba. « Properties of Concrete Produced using Surface Modified Polyethylene Terephthalate Fibres ». Civil Engineering Journal 8, no 6 (1 juin 2022) : 1115–35. http://dx.doi.org/10.28991/cej-2022-08-06-03.
Texte intégralRésumé :
Conventional techniques of improving the bond properties of virgin Polyethylene Terephthalate Fibres reduce the mechanical strength of the fibres, are labour intensive, and present environmental hazards in the case of chemical treatment. This study introduces a new way of improving the bond properties of fibres obtained from waste Polyethylene Terephthalate bottles by coating the surface of the fibres with a thin layer of sand to counteract the above-mentioned shortcomings. Their performance was compared to that of embossed, serrated, and straight fibres and a control mix without fibres. Workability, compressive strength, tensile and flexural strength were used to assess this performance. Constant fibre length, width, and content were maintained for this exercise. Compared to the other fibres, sand-coated fibres gave the highest increment in tensile and flexural strength of 9.49% and 11.61% compared to the control mix, even though concrete’s workability and compressive strength were decreased. Furthermore, the optimization of the fibre length and content for the sand-coated fibres was carried out. The 75 mm long fibres showed the highest improvement in tensile strength of 13.76% and flexural strength of 12.49% compared to other fibre lengths. The optimum percentage of fibres was 1.25% with a 15.49% and 17.26% increment in tensile and flexural strengths, respectively. Doi: 10.28991/CEJ-2022-08-06-03 Full Text: PDF
40
Do, Nhi Thi, Hop Quang Tran, Hanh Thi My Diep et Vi Thi Vi Do. « Study on properties of composites polyurethane foam reinforced by bamboo fiber ». Science and Technology Development Journal 19, no 4 (31 décembre 2016) : 212–20. http://dx.doi.org/10.32508/stdj.v19i4.693.
Texte intégralRésumé :
This study focuses on the development and characterization of polyurethane/bamboo fiber composites foams which have the specific properties to participate both in the thermal insulation and regulation of the humidity inside the building. The polyurethane foam reinforced by bamboo fibers (5–20 wt%) were produced to investigate the mechanical test, the morphological characterization and thermal properties. The result from mechanical test showed that the compressive strength was increased at 5 wt % of bamboo fiber. Likewise, the effects of the fibre diameter and nature of bamboo fibers on some properties (compressive test, thermal analyses, surface morphology) of bamboo fibre reinforced rigid polyurethane foam were studied. The bamboo Gai and Luong fibres result in composites with better mechanical strength than the other fiber composites.
41
d'Almeida, J. R. M., A. L. F. S. d'Almeida et L. H. De Carvalho. « Mechanical, Morphological, and Structural Characteristics of Caroa (Neoglaziovia variegata) Fibres ». Polymers and Polymer Composites 16, no 9 (novembre 2008) : 589–95. http://dx.doi.org/10.1177/096739110801600902.
Texte intégralRésumé :
The surface morphology, thermal behaviour and tensile mechanical properties of raw caroa (Neoglaziovia variegata) fibres have been characterised. The influence of fibre washing with flowing tap water on the surface morphology and thermal properties of these fibres has also been investigated. The results show that gummy tissues are attached to the surface of the raw fibres and that washing leads to the partial removal of these tissues and to the exposure of the inner fibrillar structure of the fibres. Thermogravimetric analysis indicates that fibre thermal degradation is characterised by three main degradation stages corresponding, respectively, to water release at low temperatures, followed by decomposition of hemicellulose and of α-cellulose. Fibre washing produces an increase in the fibre thermal degradation temperature, Tonset, and in the thermal decomposition rate. These characteristics are associated with the removal of gummy tissues and with a decrease in the compactness of the fibres respectively. The tensile properties obtained place caroa as a low-to-medium-strength fibre when compared with other lignocellulosic fibres, but with a strength level similar to that of coir fibres, which, nowadays, are used commercially on a fairly large scale.
42
Trautmann, Maik, Daisy Nestler, Bernhard Wielage et Guntram Wagner. « Method to Quantify the Surface Roughness of Circular Reinforcing Fibres ». Materials Science Forum 825-826 (juillet 2015) : 922–27. http://dx.doi.org/10.4028/www.scientific.net/msf.825-826.922.
Texte intégralRésumé :
The properties of fibre-reinforced composites depend on the interface between the matrix and the fibre. The surface of the fibres plays a key role in the load transmission. In this article, a method based on scanning electron microscopy images of fibre cross sections is introduced to quantify the surface roughness. By utilising an image editing software to get a digital profile of the fibre contour, the arithmetic roughness Ra of a carbon fibre was calculated. The method was tested on a C-fibre with a diameter of 7 microns and compared with the images of an atomic force microscopy (AFM). The method allows a comparison of different types of fibres as well as an investigation regarding the influence of fibre treatments.
43
Jenkins, Peter, Liu Yang, James Thomason, Xinyong Chen, John Watts et Steven Hinder. « Investigation of Chemical and Physical Surface Changes of Thermally Conditioned Glass Fibres ». Fibers 7, no 1 (15 janvier 2019) : 7. http://dx.doi.org/10.3390/fib7010007.
Texte intégralRésumé :
A number of analytical techniques were applied to investigate changes to the surface of unsized boron-free E-glass fibres after thermal conditioning at temperatures up to 700 °C. Novel systematic studies were carried out to investigate the fundamental strength loss from thermal conditioning. Surface chemical changes studied using X-ray photoelectron spectroscopy (XPS) showed a consistent increase in the surface concentration of calcium with increasing conditioning temperature, although this did not correlate well with a loss of fibre strength. Scanning electron microscopy fractography confirmed the difficulty of analysing failure-inducing flaws on individual fibre fracture surfaces. Analysis by atomic force microscopy (AFM) did not reveal any likely surface cracks or flaws of significant dimensions to cause failure: the observation of cracks before fibre fracture may not be possible when using this technique. Fibre surface roughness increased over the whole range of the conditioning temperatures investigated. Although surface roughness did not correlate precisely with fibre strength, there was a clear inverse relationship at temperatures exceeding 400 °C. The interpretation of the surface topography that formed between 400–700 °C produced evidence that the initial stage of phase separation by spinodal decomposition may have occurred at the fibre surface.
44
Oyedeko, K. F. K., H. O. Opaleye et G. O. Shonaike. « TENSILE PROPERTIES OF SURFACE TREATED COIR FIBRE REINFORCED POLYETHYLENE ». Engineering and Technology Research Journal 3, no 1 (16 mars 2018) : 56–60. http://dx.doi.org/10.47545/etrj.2018.3.1.075.
Texte intégralRésumé :
The need to pursue an environmentally safer future has prompted the researchers to look beyond the inorganic fibre-based composites and engage in putting more thought into the utilization of natural fibre-based polymer composites. Although inorganic fibres, such as glass and carbon have a lot of advantages but we can owe its declining use in recent years to high initial cost, non-biodegradability, non-renewability, high energy consumption in manufacturing process and adverse environmental impacts. Natural fibres however more than compensate for their poor compatibility with the matrix, inherent high moisture absorption rate with their positive attributes like low cost, low density, non-abrasivity, good thermal properties, enhanced energy recovery and bio degradability. This work is aimed at investigating the effect of alkali treatment and fibre load on the tensile properties and hardness properties of coir fibre reinforced polypropylene composites. Polypropylene (PP) was used as the matrix resin and coir fibre (CF) as the reinforcing agent. The brown coconut fibres were pulled out and extracted manually from the coconut husks. To ensure proper interaction between fibre and matrix material, the outermost wax layer of the coir was removed by soaking the coir in hot water. The coir fibres are then prepared for treatment with NaOH solution to improve its surface properties and provide better adhesion with the matrix after the removal of lignin and pectin from the surface of the fibre. The tensile properties indicated that both the strength and modulus increased with increasing fibre content. However, in this investigation, the maximum fibre content is 20%. It could have been more than this but we encountered processing problem. Alkaline treated samples had higher tensile properties than untreated samples. The hardness of the material is not significantly affected by the surface treatment.
45
Shevchenko, V. M., N. A. Guts, A. Ye Shpak, N. Ye Vlasenko et O. O. Shulzhenko. « Fungi-resistant basalt fiber material ». Surface 12(27) (30 décembre 2020) : 153–60. http://dx.doi.org/10.15407/surface.2020.12.153.
Texte intégralRésumé :
Leading industrial countries display the growth of paper industry even more than other industries. The paper is and was very important for our civilization. Technical industries also require the paper. The electro-technical, radio-technical industries use widely various kinds of paper for the production of things like cables, condensers, radio-diffusers, resistors, TV-sets and so on. In the chemical industry papers are used for chromatography, electrophoresis etc. But besides of clear advantages for simple usage there are some another advances for some usage namely materials which are resistant to mold fungi and the microorganisms. It is known that the least subject to the fungi effect are things what are consisted as linen fibers among all as well as sulfite and sulfate cellulose. The artificial fibers are more resistant than natural. Obviously the problem of conservation of already printed on paper materials growths more and more every year. Now it is strange when we can’t read old books which have not being saved in new digital formats. That is why the preserve the old paper literature in worthy state is so important for us and for future generations, and the problem of obtaining so called “biocide” material is so actual. It means such material which may destroy bacteria, mold fungi, and insects. In this work we have used the clays from Zakarpatiyan oblast Horbsky field. These clays are classified as bentonite type and have the following consistence with particular size is between 0,3 and 0,25 mm. The authors studied the sorption of latexes by basalt fibers. The following latexes were investigated: divinyl methyl methacrylate (DMMA), divinyl nitrile (SKN), isoprene nitrile (L-7). A method was used to recharge the surface of cellulose fibers to obtain a flexible, durable filter material. We checked the resistance of materials to mold.
46
Hao, Siqi, Lizhe He, Jiaqi Liu, Yuhao Liu, Chris Rudd et Xiaoling Liu. « Recovery of Carbon Fibre from Waste Prepreg via Microwave Pyrolysis ». Polymers 13, no 8 (10 avril 2021) : 1231. http://dx.doi.org/10.3390/polym13081231.
Texte intégralRésumé :
Management of waste from carbon fibre composites has become a significant societal issue as the application of composite grows across many industries. In this study, carbon fibres (CF) were successfully recovered from cured carbon fibre/epoxy (CF/EP) prepreg under microwave pyrolysis at 450, 550 and 650 °C followed by oxidation of any residual char. The recovered fibres were investigated for their tensile properties, surface morphologies and the elements/functional groups presented on the surface. The chemical compositions of gaseous and oil pyrolysis products were also analysed. The microwave pyrolysis effectively pyrolyzed the epoxy (EP) resin. Char residue remained on the fibre surface and the amount of char reduced as the pyrolysis temperature increased. Compared to virgin fibres, the recovered fibre suffered from a strength reduction by less than 20%, and this reduction could be mitigated by reducing the pyrolysis temperature. The surface of recovered fibre remained clean and smooth, while the profile of elements and functional groups at the surface were similar to those of virgin fibres. The main gaseous products were CO, H2, CO2 and CH4, whilst the liquid product stream included phenolic and aromatic compounds.
47
Fratacci, MD, M. Levame, A. Rauss, H. Bousbaa et G. Atlan. « Rat diaphragm during postnatal development. I. Changes in distribution of muscle fibre type and in oxidative potential ». Reproduction, Fertility and Development 8, no 3 (1996) : 391. http://dx.doi.org/10.1071/rd9960391.
Texte intégralRésumé :
The changes occurring in the histochemical characteristics of the rat diaphragm during the postnatal period were examined. Fibre-type distribution, fibre oxidative capacity, i.e. succinate-dehydrogenase (SDH) activity, and cross-sectional area were compared in the costal (COS) and crural (CRU) regions, and across their abdominal and thoracic surfaces. The proportions of type I and IIb fibres in both COS and CRU increased with age, while the proportion of type IIa fibres progressively decreased. For COS, fibre distribution was homogeneous over the entire muscle and did not change after 4 weeks. For CRU, it was heterogeneous with a higher proportion of type I fibres on the thoracic surface as from the first week. All fibre types significantly increased in cross-sectional area between 1 and 8 weeks, with no significant differences in COS and CRU. Mean SDH activity did not differ between COS and CRU or across the muscles. Mean SDH activities-were low and identical in all fibre types at birth, and then increased, peaking at the 6th week in type I and IIa fibres. When total muscle fibre oxidative capacity was calculated from an index including fibre-type proportion, cross-sectional area and mean SDH activity, it was significantly higher at 1 than at 8 weeks after birth; this might have functional implications for the newborn.
48
Bakri, B., A. E. E. Putra, A. A. Mochtar, I. Renreng et H. Arsyad. « Sodium Bicarbonate Treatment on Mechanical and Morphological Properties of Coir Fibres ». International Journal of Automotive and Mechanical Engineering 15, no 3 (5 octobre 2018) : 5562–72. http://dx.doi.org/10.15282/ijame.15.3.2018.12.0427.
Texte intégralRésumé :
Natural fibres as reinforcement of composite have been applied during the last decade. One of natural fibre has been used as reinforcement is coir fibre. As reinforcement of composite, such fibre needs treatment to improve compatibility with its matrix with suitable treatment. In this paper, surface treatment of such fibre was conducted using sodium bicarbonate (NaHCO3) solution with various densities and soaking time differences. Mechanical and morphological properties of coir fibre were investigated. Coir fibres were soaked in the 8 wt.%, 10 wt.%, and 12 wt.% sodium bicarbonate solution for 24 hours and 120 hours. After treatment, coir fibres were characterized with tensile testing, scanning electron microscope (SEM), Fourier transform infrared (FTIR) and x-ray diffraction (XRD). The results suggested that mechanical properties of coir fibre after sodium bicarbonate solution changed for all densities and soaking time. The coir fibre treated in 12 wt.% sodium bicarbonate for soaking time 120 hours has highest tensile strength. The surface morphology of fibre was analyzed by using SEM. It showed micropores on the fibre surface which may influence the mechanical properties of coir fibre.
49
Santhanam, V., et M. Chandrasekaran. « Effect of Surface Treatment on the Mechanical Properties of Banana-Glass Fibre Hybrid Composites ». Applied Mechanics and Materials 591 (juillet 2014) : 7–10. http://dx.doi.org/10.4028/www.scientific.net/amm.591.7.
Texte intégralRésumé :
Natural fibre reinforced composites have attracted the attention of research community mainly because they are turning out to be an alternative to synthetic fibre. Various natural fibres such as jute, sisal, palm, coir and banana are used as reinforcements. In this paper, banana fibres and glass fibres have been used as reinforcement. Hybrid epoxy polymer composite was fabricated using chopped banana/glass fibre and the effect of alkali treatment was also studied. It is found that the alkali treatment improved the mechanical properties of the composite.
50
Mohd Ghaztar, Muhammad Mustakim, Nik Noor Idayu Nik Ibrahim et Ahmad Zafir Romli. « Sodium Hydroxide/Silane Treated Kenaf Fibre in Unsaturated Polyester Matrix : Effects of Fibres Length and Fibres Loading Towards The Composites Flexural and Morphological Properties ». Journal of Mechanical Engineering 19, no 2 (15 avril 2022) : 147–67. http://dx.doi.org/10.24191/jmeche.v19i2.19769.
Texte intégralRésumé :
The fibre behaviour is a critical aspect that will determine the deformation of the composite since it highly relies on its physical and chemical properties. This paper focus on the effect of similar fibres aspect ratio (L/D) with different length of untreated Kenaf fibre and SodiumHydroxide/silane treated Kenaf fibres on the flexural properties of the composites. The treated and untreated kenaf fibre at two different fibre lengths (A: 0.4 cm and B: 2.9 cm) were fabricated at low filler loadings (5,10,15%) and high filler loadings (45,50,55%). The results showed an improvement in the flexural stress (7-44 %) and modulus (6-46 %) with the application of treatments for both A- and B- fibre categories. The optimum result was achieved from the treated samples at a shorter A-fibre composite, although the aspect ratio between A and B-fibre samples are similar. The chemical treatment coalition might improve the surface interaction and, at shorter fibre length, it affects the fibres compact-ability that led to an improvement in stress distribution and low voids formation as supported by the observation on the composite's fractured surface where traces of matrix observed on the surface of pull-out fibres. From the fractographic analysis, the fibres morphological condition before the fabrication is one of the important factors to consider since it can affect the end-properties of the composites.