Статті в журналах: "Flax fibre bundle"

1

Rayyaan, Rishad, William Richard Kennon, Prasad Potluri, and Mahmudul Akonda. "Fibre architecture modification to improve the tensile properties of flax-reinforced composites." Journal of Composite Materials 54, no. 3 (July 17, 2019): 379–95. http://dx.doi.org/10.1177/0021998319863156.

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As far as the tensile properties of natural fibres as reinforcements for composites are concerned, flax fibres will stay at the top-end. However, an efficient conversion of fibre properties into their corresponding composite properties has been a challenge, due to the fibre damages through the conventional textile methods utilised to process flax. These techniques impart disadvantageous features onto fibres at both micro- and meso-scale level, which in turn degrade the mechanical performances of flax fibre-reinforced composites (FFRC). Undulation of fibre is one of those detrimental features, which occurs during traditional fibre extraction from plant and fabric manufacturing routes. The undulation or waviness causes micro-compressive defects or ‘kink-bands’ in elementary flax fibres, which significantly undermines the performances of FFRC. Manufacturing flax fabric with minimal undulation could diminish the micro-compressive defects up to a substantial extent. In this research, nonwoven flax tapes of highly aligned flax fibres, blended with a small proportion of polylactic acid have been manufactured deploying a novel technique. Composites reinforced from those nonwoven tapes have been compared with composites reinforced with woven Hopsack fabrics and warp knitted unidirectional fabrics from flax, comprising undulating fibres. The composites reinforced with the highly aligned tapes have shown 33% higher fibre-bundle strength, and 57% higher fibre-bundle stiffness in comparison with the composites reinforced with Hopsack fabric. The results have been discussed in the light of fibre undulation, elementary fibre individualisation, homogeneity of fibre distribution, extent of resin rich areas and impregnation of the fibre lumens.

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2

Al-Hajaj, Zainab, Ahmed Sarwar, Radovan Zdero, and Habiba Bougherara. "In-situ damage assessment of a novel carbon/flax/epoxy hybrid composite under tensile and compressive loading." Journal of Composite Materials 53, no. 19 (March 29, 2019): 2701–14. http://dx.doi.org/10.1177/0021998319839129.

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Damage under progressive load–unload until failure was assessed for a new woven carbon fibre/flax fibre/epoxy hybrid composite via stiffness degradation D, permanent strain [Formula: see text], and crack density [Formula: see text]. Type A configuration had woven carbon fibres and unidirectional flax fibres (i.e. [0–90C2/0F12/0–90C2]), while Type B configuration had woven carbon fibres and ±45 ° obliquely angled flax fibres (i.e. [0–90C2/(±45)F6S/0–90C2]. Results were obtained for D in tension (Type A, 0.080; Type B, 0.089) and compression (Type A, 0.178; Type B, 0.207), [Formula: see text] in tension (Type A, 0.085%; Type B, 0.075%) and compression (Type A, 0.086%; Type B, 0.086%), and [Formula: see text] in tension (Type A, range = 0.12–1.06%; Type B, range = 0.6–1.43%) and compression (Type A, range = 0.65–1.20%; Type B, range = 1.05–2.20%). Failure involved flax fibre bundle cracks and interfacial cracks in the flax fibre/epoxy region.

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3

Titok, V., V. Leontiev, L. Shostak, and L. Khotyleva. "Thermogravimetric Analysis of the Flax Bast Fibre Bundle." Journal of Natural Fibers 3, no. 1 (June 19, 2006): 35–41. http://dx.doi.org/10.1300/j395v03n01_04.

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4

Charlet, Karine, and Alexis Beakou. "Interfaces within flax fibre bundle: Experimental characterization and numerical modelling." Journal of Composite Materials 48, no. 26 (November 18, 2013): 3263–69. http://dx.doi.org/10.1177/0021998313508871.

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5

Arbelaiz, A., B. Fernández, J. A. Ramos, A. Retegi, R. Llano-Ponte, and I. Mondragon. "Mechanical properties of short flax fibre bundle/polypropylene composites: Influence of matrix/fibre modification, fibre content, water uptake and recycling." Composites Science and Technology 65, no. 10 (August 2005): 1582–92. http://dx.doi.org/10.1016/j.compscitech.2005.01.008.

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6

Arbelaiz, A., B. Fernández, A. Valea та I. Mondragon. "Mechanical properties of short flax fibre bundle/poly(ε-caprolactone) composites: Influence of matrix modification and fibre content". Carbohydrate Polymers 64, № 2 (травень 2006): 224–32. http://dx.doi.org/10.1016/j.carbpol.2005.11.030.

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7

Straumit, Ilya, Dirk Vandepitte, Martine Wevers, and Stepan V. Lomov. "Identification of the flax fibre modulus based on an impregnated quasi-unidirectional fibre bundle test and X-ray computed tomography." Composites Science and Technology 151 (October 2017): 124–30. http://dx.doi.org/10.1016/j.compscitech.2017.07.029.

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8

Bismut, Jean-Michel, Xiaonan Ma, and Weiping Zhang. "ASYMPTOTIC TORSION AND TOEPLITZ OPERATORS." Journal of the Institute of Mathematics of Jussieu 16, no. 2 (June 11, 2015): 223–349. http://dx.doi.org/10.1017/s1474748015000171.

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We use Toeplitz operators to evaluate the leading term in the asymptotics of the analytic torsion forms associated with a family of flat vector bundles $F_{p}$. For $p\in \mathbf{N}$, the flat vector bundle $F_{p}$ is the direct image of $L^{p}$, where $L$ is a holomorphic positive line bundle on the fibres of a flat fibration by compact Kähler manifolds. The leading term of the analytic torsion forms is the integral along the fibre of a locally defined differential form.

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9

Ho, Man-Ho. "Local index theory and the Riemann–Roch–Grothendieck theorem for complex flat vector bundles." Journal of Topology and Analysis 12, no. 04 (December 7, 2018): 941–87. http://dx.doi.org/10.1142/s1793525319500699.

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The purpose of this paper is to give a proof of the real part of the Riemann–Roch–Grothendieck theorem for complex flat vector bundles at the differential form level in the even dimensional fiber case. The proof is, roughly speaking, an application of the local family index theorem for a perturbed twisted spin Dirac operator, a variational formula of the Bismut–Cheeger eta form without the kernel bundle assumption in the even dimensional fiber case, and some properties of the Cheeger–Chern–Simons class of complex flat vector bundle.

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10

CRASMAREANU, MIRCEA. "DIRAC STRUCTURES FROM LIE INTEGRABILITY." International Journal of Geometric Methods in Modern Physics 09, no. 04 (May 6, 2012): 1220005. http://dx.doi.org/10.1142/s0219887812200058.

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We prove that a pair (F = vector sub-bundle of TM, its annihilator) yields an almost Dirac structure which is Dirac if and only if F is Lie integrable. Then a flat Ehresmann connection on a fiber bundle ξ yields two complementary, but not orthogonally, Dirac structures on the total space M of ξ. These Dirac structures are also Lagrangian sub-bundles with respect to the natural almost symplectic structure of the big tangent bundle of M. The tangent bundle in Riemannian geometry is discussed as particular case and the 3-dimensional Heisenberg space is illustrated as example. More generally, we study the Bianchi–Cartan–Vranceanu metrics and their Hopf bundles.

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11

Camano, Sabela, Nemeshwaree Behary, Philippe Vroman, and Christine Campagne. "Comparison of Bio and Eco-technologies with Chemical Methods for Pre-treatment of Flax Fibers: Impact on Fiber Properties." Journal of Engineered Fibers and Fabrics 9, no. 4 (December 2014): 155892501400900. http://dx.doi.org/10.1177/155892501400900407.

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Flax fibers, available as fiber bundles, are commonly used as fiber reinforcement in composite materials as a substitute for glass fibers. Pre-treatments are often necessary for improving fiber-resin adhesion, and also to facilitate fiber elementarization, and to improve fiber ability to be implemented in mechanical processes limiting fiber damages. This paper focuses on the impact of biotechnologies (effect of 2 different enzymes: a pectate lyase and a laccase) and of an ecotechnology (ultrasound with ethanol), compared to classical chemical pre-treatments (using aqueous NaOH and ammonia) on the final flax fiber bundle properties, before and after a carding process. Fiber surface properties (wettability and/or zeta potential values), fiber elementarization and mechanical properties vary with the type of treatment (chemical nature of product and conditions used). Fibers elementarised using pectate lyase and ultrasound/ethanol have a hydrophilic surface and a high water absorption capacity, and are also of highest quality in terms of increased fineness. Treatment with NaOH yields the poorest fiber bundle tenacity. Laccase enzyme yields long thick hydrophobic fibers having very low water absorption capacity, and the most neutral surface charge. Properties of flax fibers can be easily monitored using different pre-treatments resulting in fibers which would be suited for various final applications.

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12

Soete, Karen, Frederik Desplentere, Stepan V. Lomov, and Dirk Vandepitte. "Variability of flax fibre morphology and mechanical properties in injection moulded short straw flax fibre-reinforced PP composites." Journal of Composite Materials 51, no. 23 (December 13, 2016): 3337–49. http://dx.doi.org/10.1177/0021998316683781.

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The influence of compounding and injection moulding on the initial variability and morphology of short straw flax fibres is determined and the mechanical properties for the injection moulded fibre reinforced composites are measured. It is found that the composition of the straw flax, flax fibre bundles and woody parts, together with the cutting process strongly affects the initial fibre morphology and its variability. In the initial fibres, small particles as well as long fibres with large width were found. A filter was used to reject the fibres with an aspect ratio below 15 before calculating statistics because these fibres have a negligible contribution to the composite reinforcement. After processing, the initial fibre length and width decrease strongly (−38% to −66% for length and −22% to −72% for width). Also, the variability is affected resulting in a standard deviation shifted towards lower fibre lengths and widths (−55% for length and −71% for width). The improvement of mechanical properties of the flax compound compared to the pure matrix material for the injection-moulded samples is found to be similar to the results for compounds with further processed flax fibres such as scutched and hackled fibres. An increase of tensile strength by 20% was found, for stiffness the increase is in the order of 50–70%. This indicates that despite the very large variability of the initial straw flax fibres and the strong changes of the variability in each processing step, a compound is obtained with improved mechanical properties.

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13

Aleeva, Svetlana V., Olga V. Lepilova,, Polina Yu Kurzanova, and Sergey A. Koksharov. "SPECIFICITY OF CHANGE IN SORPTION CAPACITY OF FLAX FIBER UNDER REGULABLE BIO-CATALYTICAL DESTRUCTION OF NEUTRAL CARBOHYDRATES." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 61, no. 2 (January 29, 2018): 80. http://dx.doi.org/10.6060/tcct.20186102.5512.

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Evaluation of the nano sizes of hydrosols from homogeneous cellulosic and industrial products was made using dynamic light scattering method. The influence of the size of the globule of protein catalysts and the duration of their action on the roving of carded flax fiber was compared. The correlation between the change in the equilibrium absorption of sorption marker (methylene blue) and residual content in the fiber of hemicelluloses was monitored. On the basis of a comparative analysis of the efficiency of biocatalysts in industrial homogeneous and cellulosic preparations it was revealed that globule size influences on the efficiency of sorption properties of flax fibers. The use of homogeneous enzymes with differing sized parameters has allowed isolating the contribution of the target enzymatic modification as in the microfibrillar structure of elementary fibers and for modification the hemicelluloses in the binding substance fixing the elementary fibers in the bast bundles (the linen fibrous complexes). The principles of selection of biocatalysts to increase sorption capacity in flax fiber sorbents were revealed. It was found that the sorption capacity of flax fiber sorbents increases due to the development of mezopore space in elementary fibres and regulable amorphization of interfiber binders in the structure of the linen complex. The research revealed that the the amorphization of flax fiber took place only when the cellulases was used. The size of their globules enables the penetration of these enzymes into mesopores of elementary flax fibres. It was established experimentally that the presence of large isoforms of cellulases or hemicellulases can promote as the development of the internal volume into the fibre binders and also conservation the permissible level of reduction of the hemicelluloses amount in flax fibres is not less than 10 mass.%.Forcitation:Aleeva S.V., Lepilova O.V., Kurzanova P.Yu., Koksharov S.A. Specificity of change in sorption capacity of flax fiber under regulable bio-catalytical destruction of neutral carbohydrates. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2018. V. 61. N 2. P. 80-85

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14

Morita, Shigeyuki. "Families of Jacobian manifolds and characteristic classes of surface bundles. II." Mathematical Proceedings of the Cambridge Philosophical Society 105, no. 1 (January 1989): 79–101. http://dx.doi.org/10.1017/s0305004100001389.

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Let Σg be a closed orientable surface of genus g, which will be assumed to be greater than one throughout this paper. In our previous paper [11], we have associated to any oriented ∑g-bundle π: E → X with a cross-section s: X → E a flat T2g-bundle π: J → X and a fibre-preserving embedding j: E → J such that the restriction of j to any fibre Ep = π−1(p)(p ∈ X) is equivalent to the Jacobi mapping of Ep with respect to some conformal structure on it and relative to the base-point s(p) ∈ Ep. There is a canonical oriented S1-bundle over J and the main result of [11] is the identification of the Euler class of the pullback of this S1-bundle by the map j as an element of H2(E, ). In this paper we deal with the case of Σg-bundles without cross-sections. First of all we associate a flat T2g-bundle π′: J′ → X to any oriented Σg-bundle π: E → X and construct a fibre-preserving embedding j′: E → J′ such that the restriction of j′ to any fibre Ep is equivalent to some translation of the Jacobi mapping of it. Although our original motivation for the present work came from a different source, this should be considered as a topological version of Earle's embedding theorem [5] which states that any holomorphic family of compact Riemann surfaces over a complex manifold can be embedded in a certain associated family of the corresponding Jacobian varieties in an essentially unique way.

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15

Ndoumou, Rémy Legrand, Damien Soulat, Ahmad Rashed Labanieh, Manuela Ferreira, Lucien Meva’a, and Jean Atangana Ateba. "Characterization of Tensile Properties of Cola lepidota Fibers." Fibers 10, no. 1 (January 12, 2022): 6. http://dx.doi.org/10.3390/fib10010006.

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Plant fibers are being increasingly explored for their use in engineering polymers and composites, and many works have described their properties, especially for flax and hemp fibers. Nevertheless, the availability of plant fibers varies according to the geographical location on the planet. This study presents the first work on the mechanical properties of a tropical fiber extracted from the bast of Cola lepidota (CL) plant. After a debarking step, CL fibers were extracted manually by wet-retting. The tensile properties are first identified experimentally at the fibers scale, and the analysis of the results shows the great influence of the cross-section parameters (diameter, intrinsic porosities) on these properties. Tensile properties of CL fibers are also predicted by the impregnated fiber bundle test (IFBT). At this scale of bundles, a hackling step, which reduces shives and contributes to the parallelization of the fibers within bundles, improves tensile properties predicted by IFBT. The comparison with the properties of plant fibers given in the literature shows that CL fibers have tensile properties in the same range as kenaf, flax or hemp fibers.

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Bliznakova, Kristina, Zacharias Kamarianakis, Aris Dermitzakis, Zhivko Bliznakov, Ivan Buliev, and Nicolas Pallikarakis. "Modelling of small CFRP aerostructure parts for X-ray imaging simulation." International Journal of Structural Integrity 5, no. 3 (August 12, 2014): 227–40. http://dx.doi.org/10.1108/ijsi-02-2014-0009.

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Purpose – The purpose of this paper is to develop a realistic computational model of carbon fibre reinforced polymer (CFRP) structures dedicated for in-silico investigations of the use of X-ray-based imaging techniques as non-destructive testing (NDT) of CFRP parts. Design/methodology/approach – CFRPs contain layers of carbon-fibres bundles within resin. Bundles’ orientation in the different layers is arranged with respect to each other at a well-defined primary direction. In the model, the bundle was simulated as a circular cylinder. The resulted model is a stack of layers of unidirectional bundles having orientation of 0°/90°/45°/−45°. Two CFRP structures were modelled: a flat CFRP part and a real shaped CFRP clip. A porous layer and non-carbon fibres were inserted within each model, respectively. X-ray projection images were generated with a dedicated simulation programme. Three setups were investigated: radiography, tomosynthesis and cone-beam CT (CBCT). Findings – Results showed that porosity and non-carbon fibres were visible with all X-ray-based techniques. Tomosynthesis and CBCT, however, provide higher quality image of defects. Practical implications – The CFRP computational model is a valuable tool in design, testing and optimization phase of X-ray-based imaging techniques for use in NDT of composite materials. Simulated images are generated within a short time; thus results from virtual optimization and testing are obtained very fast and at low cost. Originality/value – An innovative computational model of CFRP structures, dedicated for X-ray imaging simulations, has been developed. The model is characterized by simplicity in its creation and realistic visual appearance of the produced X-ray images.

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17

Nguyen-Chung, Tham, Klaus Friedrich, and Günter Mennig. "Processability of Pultrusion Using Natural Fiber and Thermoplastic Matrix." Research Letters in Materials Science 2007 (2007): 1–5. http://dx.doi.org/10.1155/2007/37123.

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Fundamental mechanisms of the pultrusion process using commingled yarns of polypropylene matrix and discontinuous flax fiber to produce thermoplastic profiles were investigated in numerical and experimental manners. Essential issue is the fact that all natural fibers are discontinuous by nature, which may negatively influence the processability. The pultrusion process will be only successful if the pulling force exerted on the solidified pultrudates can be transmitted to the regions of unmelted commingled yarns by “bridging over” those melted regions within the die. This can be realized by applying a sufficient number of small yarn bundles of high compactness rather than a thicker single bundle of lower compactness as the raw material. Furthermore, the possibility of adding extra melt into the yarn bundles by side-fed extrusion has been investigated showing that the impregnation can be improved only for the outer layers of yarns, which is owed to the high viscosity of the thermoplastic melt and the limited length of the die.

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18

Pavlov, Andrey, Janka Nôžková, Miroslava Šavrtková, Inna Matvienko, and Nina Brutch. "Photoperiod Influence on the Stem Structure of Fibre Flax." Agriculture (Pol'nohospodárstvo) 64, no. 4 (December 1, 2018): 160–72. http://dx.doi.org/10.2478/agri-2018-0017.

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Abstract Plants of 13 fibre flax varieties were tested for their photosensitivity and differences of stems structure while grown in long and short daylight. It was detected that seven varieties did not change time of flowering in short 12 hours daylight in comparison with long 19 hours daylight. The extended diversity of fibre flax reactions on photoperiod changes and its relative independence of photosensitivity degree were found. Also, weak but significant correlation was found between photosensitivity coefficient and the degree of leaves number increase (r = 0.57). At the same time photo insensitive variety Belosnezhka improved leaves number up to 34%. Numbers of fibre bundles, their individual and total area on the stem cross section were not changed or reduced. Width, height, perimeter and shape of fibre bundles on a cross sections changed multidirectional. The areas of stem, its wooden part and cavity on a cross section showed no significant differences between plants grown in long and short day conditions. Evaluated flax characters were not strictly correlated with each other except those indicating the structure of fibre bundles. For breeding it is important that their relationships are not strongly influenced by the environment.

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19

Guan, Guo Yang, Gui Qiong Jiao, and Tao Huang. "Experimental Research on Failure Mechanism of a CVI-Fabricated Ceramic Matrix Composite under Compression." Key Engineering Materials 326-328 (December 2006): 1841–44. http://dx.doi.org/10.4028/www.scientific.net/kem.326-328.1841.

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Mechanical tests have been conducted to understand compressive behavior of a plain weave C/SiC composite, especially to investigate the failure mechanism. The stress-strain curves of this composite show linear feature in compression. The specimens fail along a flat plane 13°~15° to the weave plane, running across four typical regions in the bulk: weft bundle, warp/weft interface, warp bundle, and inter-ply. According to the observed fracture route, four basic failure modes are schematically presented. Cracks form and develop in these areas along fiber/matrix interphase or within matrix, depending on the strength competition between interphase and matrix. The fracture mechanism reveals dependence of compress strength on matrix abundance between and within bundles. Based on the failure modes new method for compress strength prediction can be further investigated.

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20

Antonini, Paolo, Sara Azzali та Georges Skandalis. "Flat bundles, von Neumann algebras andK-theory with ℝ/ℤ-coefficients". Journal of K-Theory 13, № 2 (24 лютого 2014): 275–303. http://dx.doi.org/10.1017/is014001024jkt253.

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AbstractLetMbe a closed manifold andα:π1(M) →Una representation. We give a purelyK-theoretic description of the associated element in theK-theory group ofMwith ℝ/ℤ-coefficients ([α] ∈K1(M; ℝ/ℤ)). To that end, it is convenient to describe the ℝ/ℤ-K-theory as a relativeK-theory of the unital inclusion of ℂ into a finite von Neumann algebraB. We use the following fact: there is, associated withα, a finite von Neumann algebraBtogether with a flat bundleℰ→Mwith fibersB, such thatEα⊗ℰis canonically isomorphic with ℂn⊗ℰ, whereEαdenotes the flat bundle with fiber ℂnassociated withα. We also discuss the spectral flow and rho type description of the pairing of the class [α] with theK-homology class of an elliptic selfadjoint (pseudo)-differential operatorDof order 1.

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21

Jewell, Dennis E., Matthew I. Jackson, Chun-Yen Cochrane, and Dayakar V. Badri. "Feeding Fiber-Bound Polyphenol Ingredients at Different Levels Modulates Colonic Postbiotics to Improve Gut Health in Cats." Animals 12, no. 13 (June 27, 2022): 1654. http://dx.doi.org/10.3390/ani12131654.

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Consumption of fiber in its different forms can result in positive health effects. Prior studies in dogs found that addition of a fiber bundle (composed of pecan shells, flax seed, and powders of cranberry, citrus, and beet) to food resulted in a shift in fecal bacterial metabolism from proteolysis to saccharolysis. The present study evaluated the changes in fecal metabolites and microbiota in healthy cats following the consumption of this fiber bundle. Following a 28-day pre-feed period, 56 healthy adult cats received food with none or one of three concentrations (0%, 1%, 2%, and 4%) of the fiber bundle for a 31-day period. In cats that consumed the 4% fiber bundle, levels of ammonium and fecal branched-chain fatty acids (BCFAs) decreased from baseline and compared with the other groups. Addition of any level of the fiber bundle resulted in increases in beneficial metabolites: polyphenols hesperidin, hesperetin, ponciretin, secoisolariciresinol diglucoside, secoisolariciresinol, and enterodiol. Little change in fecal microbiota was observed. Since higher levels of ammonia and BCFAs indicate putrefactive metabolism, the decreases in these with the 4% fiber bundle indicate a shift toward saccharolytic metabolism despite little change in the microbiota composition.

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22

Du, Guang-Hui, Fei-Hu Liu, and Gordon Rowland. "Fiber cell development and fiber yield of flax (Linum usitatissimum L.) affected by the seasonal temperature pattern." Canadian Journal of Plant Science 95, no. 6 (November 2015): 1215–20. http://dx.doi.org/10.4141/cjps-2014-185.

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Du, G.-H., Liu, F.-H. and Rowland, G. 2015. Fiber cell development and fiber yield of flax (Linum usitatissimum L.) affected by the seasonal temperature pattern. Can. J. Plant Sci. 95: 1215–1220. Three fiber flax cultivars ‘Ariane’, ‘Argos’ and ‘Viking’ were cultured in growth chambers under three seasonal temperature patterns (STPs) [parabolic (P), anti-parabolic (AP) and quasi-horizontal (QH) configurations]. The effect of STP was studied on fiber cell development and on fiber yield. The results indicated that, compared with the quasi-horizontal seasonal temperature pattern (QH-STP), the size of fiber cell cavity (SFCC) and fiber content (FC) decreased under parabolic seasonal temperature pattern (P-STP). However, the size of fiber cell (SFC) and SFCC decreased, but the number of fiber cells per bundle (NFCB) increased under anti-parabolic seasonal temperature pattern (AP-STP). Moreover, there was a significant positive correlation between fiber weight (FW) and width of fiber bundle (WFB), also between FC and NFCB. Considering the response of fiber flax cultivars to the different STPs, ‘Ariane’ had smaller SFC and SFCC, thinner thickness of fiber cell wall (TFCW) under AP-STP, and smaller SFCC and thicker TFCW under P-STP than under QH-STP, while ‘Argos’ had smaller SFC and SFCC, and higher NFCB under AP-STP, and smaller SFC under P-STP than under QH-STP. However, STPs had little effect on the fiber cell development of ‘Viking’. All three cultivars had high FC under AP-STP than under P-STP. These observations indicate that the fiber cell development and fiber yield of flax were related to the STP and suggest that AP-STP are the most favorable temperature conditions for fiber flax growth.

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23

Lim, T. C., S. Ramakrishna, and H. M. Shang. "Effect of Fibre Bundle Structure on Stretch Forming Properties of Plain Weft-Knitted Fabric Composites." Advanced Composites Letters 8, no. 4 (July 1999): 096369359900800. http://dx.doi.org/10.1177/096369359900800402.

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Knitted fabrics are known for their excellent stretchability and their flat composites have recently been shown to be easily stretch-formed into thin shells of revolution. In this paper, the stretch-forming properties are being investigated with due attention given to the fibre bundle loop structure. The capability of a plain weft-knitted fabric composite sheet to be stretch-formed is elucidated with reference to the fibre bundle structure.

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24

Catanese, Fabrizio, and Michael Dettweiler. "Vector bundles on curves coming from variation of Hodge structures." International Journal of Mathematics 27, no. 07 (June 2016): 1640001. http://dx.doi.org/10.1142/s0129167x16400012.

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Анотація:

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.

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Jewell, Dennis E., Matthew I. Jackson, Chun-Yen Cochrane, and Dayakar V. Badri. "Feeding Fiber-Bound Polyphenol Ingredients at Different Levels Modulates Colonic Postbiotics to Improve Gut Health in Dogs." Animals 12, no. 5 (March 2, 2022): 627. http://dx.doi.org/10.3390/ani12050627.

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This study assessed changes in canine fecal metabolites and microbiota with the consumption of foods with increasing concentrations of a fiber bundle including pecan shells, flax seed, and powders of cranberry, citrus, and beet that was previously shown (at 14% w/w) to improve stool quality, shift fecal bacterial metabolism from proteolysis to saccharolysis, increase abundance of saccharolytic bacteria, and decrease abundance of proteolytic bacteria. In this study, 48 healthy adult dogs were split evenly to consume different inclusion levels (0%, 1%, 2%, and 4%) of the fiber bundle for a 31-day period following a 28-day pre-feed period. Increases from baseline in the fecal short-chain fatty acids butyric acid, valeric acid, and hexanoic acid were observed only in the dogs that consumed the food with the 4% fiber bundle. With addition of any level of the fiber bundle, increases were seen in the polyphenols hesperidin, hesperetin, ponciretin, secoisolariciresinol diglucoside, secoisolariciresinol, and enterodiol. However, fecal microbiota and their metabolism, and stool scores were largely unaffected by the fiber bundle. Overall, addition of the fiber bundle appeared to increase bioactive metabolites of increased antioxidant and anti-inflammatory potency for beneficial to health and, at levels ≥4%, shifted gut bacterial metabolism toward saccharolysis.

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26

Ozdemir, Huseyin, and Kadir Bilisik. "Off-Axis Flexural Properties of Multiaxis 3D Basalt Fiber Preform/Cementitious Concretes: Experimental Study." Materials 14, no. 11 (May 21, 2021): 2713. http://dx.doi.org/10.3390/ma14112713.

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Анотація:

Multiaxis three-dimensional (3D) continuous basalt fiber/cementitious concretes were manufactured. The novelty of the study was that the non-interlace preform structures were multiaxially created by placing all continious filamentary bundles in the in-plane direction of the preform via developed flat winding-molding method to improve the fracture toughness of the concrete composite. Principle and off-axis flexural properties of multiaxis three-dimensional (3D) continuous basalt fiber/cementitious concretes were experimentally studied. It was identified that the principle and off-axis flexural load-bearing, flexural strength and the toughness properties of the multiaxis 3D basalt concrete were extraordinarily affected by the continuous basalt filament bundle orientations and placement in the pristine concrete. The principle and off-axis flexural strength and energy absorption performance of the uniaxial (B-1D-(0°)), biaxial ((B-2D-(0°), B-2D-(90°) and B-2D-(+45°)), and multiaxial (B-4D-(0°), B-4D-(+45°) and B-4D-(−45°)) concrete composites were considerably greater compared to those of pristine concrete. Fractured four directional basalt concretes had regional breakages of the brittle cementitious matrix and broom-like damage features on the filaments, fiber-matrix debonding, intrafilament bundle splitting, and minor filament entanglement. Multiaxis 3D basalt concrete, particularly in the B-4D structure, controlled the crack phenomena and it was recognized as a more damage-tolerant material than the neat concrete.

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27

Huang, Zhong Yao, Li Hai Cai, and Jian Xiong Yang. "Research on Flexural Fatigue of Fiber Bundles for Lay-Flat Hose." Applied Mechanics and Materials 320 (May 2013): 512–17. http://dx.doi.org/10.4028/www.scientific.net/amm.320.512.

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This paper studies the flexural fatigue performance for hose reinforcement layer fiber bundles including polyester fibers, para-aramid fiber and liquid crystal polyester fiber. Bending fatigue life and changes of three fiber bundles strength during the course of fatigue development were measured. Morphology of three fiber bundles was observed by scanning electron microscopy. From the analysis of the molecular structure of the three fibers, the Molecular chain flexibility is one of the main factors of impacting resistance to bending fatigue performance. Liquid crystal polyester fiber bundles have excellent mechanical properties and the high strength retention in bending fatigue test, which is an ideal material for the production of high-strength hose.

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28

Gautreau, Maxime, Antoine Kervoelen, Guillaume Barteau, François Delattre, Thibaut Colinart, Floran Pierre, Maxime Hauguel, et al. "Fibre Individualisation and Mechanical Properties of a Flax-PLA Non-Woven Composite Following Physical Pre-Treatments." Coatings 11, no. 7 (July 14, 2021): 846. http://dx.doi.org/10.3390/coatings11070846.

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Анотація:

Pre-treatments for plant fibres are very popular for increasing the fineness of bundles, promoting individualisation of fibres, modifying the fibre-matrix interface or reducing water uptake. Most pre-treatments are based on the use of chemicals and raise concerns about possible harmful effects on the environment. In this study, we used physical pre-treatments without the addition of chemical products. Flax tows were subjected to ultrasound and gamma irradiation to increase the number of elementary fibres. For gamma pre-treatments, a 20% increase in the number of elementary fibres was quantified. The biochemical composition of pre-treated flax tows exhibited a partial elimination of sugars related to pectin and hemicelluloses depending on the pre-treatment. The hygroscopic behaviour showed a comparable decreasing trend for water sorption-desorption hysteresis for both types of pre-treatment. Then, non-woven composites were produced from the pre-treated tows using poly-(lactid) (PLA) as a bio-based matrix. A moderate difference between the composite mechanical properties was generally demonstrated, with a significant increase in the stress at break observed for the case of ultrasound pre-treatment. Finally, an environmental analysis was carried out and discussed to quantitatively compare the different environmental impacts of the pre-treatments for composite applications; the environmental benefit of using gamma irradiation compared to ultrasound pre-treatment was demonstrated.

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Foulk, Jonn A., Denis Rho, Mercedes M. Alcock, Chad A. Ulven, and Shanshan Huo. "Modifications Caused by Enzyme-Retting and Their Effect on Composite Performance." Advances in Materials Science and Engineering 2011 (2011): 1–9. http://dx.doi.org/10.1155/2011/179023.

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Анотація:

Bethune seed flax was collected from Canada with seed removed using a stripper header and straw pulled and left in field for several weeks. Unretted straw was decorticated providing a coarse fiber bundle feedstock for enzyme treatments. Enzyme treatments using a bacterial pectinolytic enzyme with lyase activity were conducted in lab-scale reactors. Four fiber specimens were created: no retting, minimal retting, moderate retting, and full retting. Fiber characterization tests: strength, elongation, diameter, metal content, wax content, and pH were conducted with significant differences between fibers. Thermosetting vinyl ester resin was used to produce composite panels via vacuum-assisted infusion. Composite performance was evaluated using fiber bundle pull-out, tensile, impact, and interlaminar shear tests. Composite tests indicate that composite panels are largely unchanged among fiber samples. Variation in composite performance might not be realized due to poor interfacial bonding being of larger impact than the more subtle changes incurred by the enzyme treatment.

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Nasatyr, Emile Ben. "Seifert-fibred homology 3-spheres,V-surfaces and the Floer index." Mathematical Proceedings of the Cambridge Philosophical Society 111, no. 3 (May 1992): 461–85. http://dx.doi.org/10.1017/s0305004100075563.

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Let Σ be a Seifert-fibred homology 3-sphere. We are interested in the chain complex for the Floer homology of Σ. This is generated by the critical points of the ChernSimons functional acting on the moduli space of irreducibleSU(2)-connections modulo gauge-equivalence, i.e. the equivalence classes of flat connections: see [6]. Specifically, we ask the question: given the holonomy ρ of a flat connectionCρ, what is the index ofCρin the chain complex? By definition thisFloer indexis given by the spectral flow of a family of twisted signature operators with coefficients in the adjoint bundle (with fibre su(2)) corresponding to any path of connections joining the trivial connection toCρ. We will calculate this spectral flow by an almost entirely direct method, obtaining a formula in terms of the dimensions of spaces of π1(Σ)- automorphic functions. These dimensions will be evaluated to give the numerical result previously obtained using a different method by Fintushel and Stern: see [5].

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Zou, Ling Chunxian, and Chris Hunt. "A new approach to investigate conductive anodic filament (CAF) formation." Soldering & Surface Mount Technology 27, no. 1 (February 2, 2015): 22–30. http://dx.doi.org/10.1108/ssmt-02-2014-0002.

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Purpose – This paper aims to describe the development of an approach that uses a flexible substrate to investigate the mechanism of conductive anodic filament (CAF) growth and effect of different material and manufacturing variables. Design/methodology/approach – A new approach using a simulated test vehicle (STV) has been developed to study the CAF phenomena. The STV can be easily built under controlled conditions in the laboratory using different glass fibres and resin powder to investigate the effect of different variables separately on CAF. The advantage of the STV is that CAF can be formed in relatively short period in a controlled way, and CAF growth can be easily identified using a back-lighting under a microscope due to the thin flex material used as the test sample. Findings – STV has been used to investigate a number of effects on CAF formation: different glass fibres, reflow process, acid contamination in drilled holes, desmear process and glass bundle size. The results demonstrate that for finished fibres acid contamination (plating solution) at the electrode was necessary for CAF formation. However, for unfinished glass fibres (loom state and heat cleaned) CAF can be formed without acid contamination. The reflow process significantly increases CAF formation. Running an aggressive desmear process and using large glass fibre bundle also increased CAF formation. Originality/value – This new approach will be of benefit for printed circuit board (PCB) supplier to evaluate CAF performance on different resin systems and glass fibres to provide high CAF resistance quality PCBs. The test period (168 hours) would be much shorter than the traditional CAF testing (1,000 hours).

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32

Gogoli, Komlavi, Florian Gehring, Christophe Poilâne, and Magali Morales. "Analysis of morphological variations of flax fibre bundles by Fraunhofer diffraction." Industrial Crops and Products 171 (November 2021): 113856. http://dx.doi.org/10.1016/j.indcrop.2021.113856.

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33

Lansiaux, Henri, Damien Soulat, François Boussu, and Ahmad Rashed Labanieh. "Development and Multiscale Characterization of 3D Warp Interlock Flax Fabrics with Different Woven Architectures for Composite Applications." Fibers 8, no. 2 (February 18, 2020): 15. http://dx.doi.org/10.3390/fib8020015.

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Анотація:

Multiscale characterization of the textile preform made of natural fibers is an indispensable way to understand and assess the mechanical properties and behavior of composite. In this study, a multiscale experimental characterization is performed on three-dimensional (3D) warp interlock woven fabrics made of flax fiber on the fiber (micro), roving (meso), and fabric (macro) scales. The mechanical tensile properties of the flax fiber were determined by using the impregnated fiber bundle test. The effect of the twist was considered in the back-calculation of the fiber stiffness to reveal the calculation limits of the rule of mixture. Tensile tests on dry rovings were carried out while considering different twist levels to determine the optimal amount of twist required to weave the flax roving into a 3D warp interlock. Finally, at fabric-scale, six different 3D warp interlock architectures were woven to understand the role of the architecture of binding rovings on the mechanical properties of the dry 3D fabric. The results reveal the importance of considering the properties of the fiber and roving at these scales to determine the more adequate raw material for weaving. Further, the characterization of the 3D woven structures shows the preponderant role of the binding roving on their structural and mechanical properties.

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34

Hu, Wei, Minh-Tan Ton-That, Johanne Denault, and Christian Belanger. "Characterization of polypropylene composites reinforced with flax fibers treated by mechanical and alkali methods." Science and Engineering of Composite Materials 18, no. 1-2 (June 1, 2011): 79–85. http://dx.doi.org/10.1515/secm.2011.011.

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AbstractFlax is a type of natural fiber widely used as reinforcing materials for polymer composites. The commercially available flax fibers in Canada consist of a significant amount of shive and other impurities, which could act as stress concentration regions to negatively affect the mechanical property of composites. In this study, the shive was manually removed from the commercial flax fibers by screening and combing to obtain different shive contents from 0 to 30 wt%. By contrast, the obtained flax fibers were further treated with alkaline solution. The fibers obtained from mechanical and alkali treatment were compared on their thermal and mechanical properties. As expected, it was found that the thermal stability and mechanical properties of the flax reinforced polypropylene composites increased significantly with the removal of the shive content. However, the alkali treatment on flax fiber did not further improve the composites properties. The possible reason was that the proper mechanical treatment (screening and combing) prior to alkaline treatment effectively loosened the fiber bundles for better single fiber separation in matrix and significantly removed the impurities, thus the effect of alkaline treatment did not become obvious.

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35

Baley, Christophe, Camille Goudenhooft, Patrick Perré, Pin Lu, Floran Pierre, and Alain Bourmaud. "Compressive strength of flax fibre bundles within the stem and comparison with unidirectional flax/epoxy composites." Industrial Crops and Products 130 (April 2019): 25–33. http://dx.doi.org/10.1016/j.indcrop.2018.12.059.

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36

Blum, Adrien, Mélanie Bressan, Abderrakib Zahid, Isabelle Trinsoutrot-Gattin, Azeddine Driouich, and Karine Laval. "Verticillium Wilt on Fiber Flax: Symptoms and Pathogen Development In Planta." Plant Disease 102, no. 12 (December 2018): 2421–29. http://dx.doi.org/10.1094/pdis-01-18-0139-re.

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Анотація:

Fiber flax (Linum usitatissimum L.), an important crop in Normandy (France), is increasingly affected by Verticillium wilt caused by the soilborne fungus Verticillium dahliae. This disease leads to nonnegligible yield losses and depreciated fibers that are consequently difficult to upgrade. Verticillium wilt is a major threat to a broad range of agriculture. In this study, susceptible fiber flax cultivar Adélie was infected by VdLu01 (isolated from fiber flax, this study) or green fluorescent protein-tagged VdLs17 (transformed and provided by the department of Plant Pathology, University of California, Davis). Between 3 and 4 weeks postinoculation, wilting symptoms on leaves were first observed, with acropetal growth during the following weeks. Pathogen development was tracked by confocal laser-scanning microscopy during the asymptomatic and symptomatic stages. First, conidia germination led to the development of hyphae on root epidermis; more particularly, on the zone of cell differentiation and around emerging lateral roots, while the zone of cell division and the root tip were free of the pathogen. At 3 days postinoculation, the zone of cell differentiation and lateral roots were embedded into a fungal mass. Swelling structures such as appressoria were observed at 1 week postinoculation. At 2 weeks postinoculation and onward, the pathogen had colonized xylem vessels in roots, followed by the stem and, finally, leaves during the symptomatic stage. Additionally, observations of infected plants after retting in the field revealed microsclerotia embedded inside the bast fiber bundle, thus potentially contributing to weakening of fiber. All of these results provide a global account of V. dahliae development when infecting fiber flax.

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Saadati, Yousef, Gilbert Lebrun, Jean-Francois Chatelain, and Yves Beauchamp. "Experimental investigation of failure mechanisms and evaluation of physical/mechanical properties of unidirectional flax–epoxy composites." Journal of Composite Materials 54, no. 20 (January 27, 2020): 2781–801. http://dx.doi.org/10.1177/0021998320902243.

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Using natural fibers as reinforcement in polymer matrix composites necessitates evaluating the latter under different modes of solicitation. This allows extracting its material properties for engineering design and research purposes. The main objective of the study is preparing a consistent set of material properties for unidirectional flax fiber-reinforced epoxy composite with defined composition and basic configuration. These data are prerequisites for growing researches on flax fiber-reinforced epoxy composites, especially for numerical analysis purposes using the finite element method. In this work, partially green unidirectional-flax fiber-reinforced epoxy composites are tested for physical and mechanical properties and studied for their failure modes. Tension, compression, flexion, and shear properties, as well as physical properties like density, specific heat capacity and thermal diffusivity, are evaluated according to ASTM standard test methods. Flax fibers, which are composites by themselves, come in bundles in the composites and demonstrate a complex behavior. Therefore, a fractographic analysis has been conducted to understand the macro and microscale failure mechanisms to correlate them with the material properties. The results are in good agreement with those of the literature, when available, but they mainly show the specific behavior of unidirectional-flax composites subject to different solicitation modes, especially compression and direct shear modes evaluated this way for the first time for unidirectional-flax fiber-reinforced epoxy composite. They cover most of the data required for engineering design and numerical analysis by methods like finite element method, particularly for simulating the machining process of flax fiber-reinforced epoxy composite in the ongoing works.

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38

Ling, Chengting, Xiupin Wang, Zuran Li, Yongmei He, and Yuan Li. "Effects and Mechanism of Enhanced UV-B Radiation on the Flag Leaf Angle of Rice." International Journal of Molecular Sciences 23, no. 21 (October 24, 2022): 12776. http://dx.doi.org/10.3390/ijms232112776.

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Анотація:

Leaf angle is an influential agricultural trait that influences rice (Oryza sativa L.) plant type and yield, which results from the leaf bending from the vertical axis to the abaxial axis. UV-B radiation affects plant morphology, but the effects of varying UV-B intensities on rice flag leaves and the underlying molecular, cellular, and physiological mechanisms remain unknown. This experiment aims to examine the effect of natural light and field-enhanced UV-B radiation (2.5, 5.0, 7.5 kJ·m−2) on the leaf angle of the traditional rice variety Baijiaolaojing on Yuanyang terraces. In comparison with natural light, the content of brassinolide and gibberellin in rice flag leaves increased by 29.94% and 60.1%, respectively. The auxin content decreased by 17.3%. Compared with the natural light treatment, the cellulose content in the pulvini was reduced by 13.8% and hemicellulose content by 25.7% under 7.5 kJ·m−2 radiation intensity. The thick-walled cell area and vascular bundle area of the leaf pulvini decreased with increasing radiation intensity, and the growth of mechanical tissue in the rice leaf pulvini was inhibited. The flag leaf angle of rice was greatest at 7.5 kJ·m−2 radiation intensity, with an increase of 50.2%. There are two pathways by which the angle of rice flag leaves is controlled under high-intensity UV-B radiation. The leaf angle regulation genes OsBUL1, OsGSR1, and OsARF19 control hormone levels, whereas the ILA1 gene controls fiber levels. Therefore, as cellulose, hemicellulose, sclerenchyma, and vascular bundles weaken the mechanical support of the pulvini, the angle of the flag leaf increases.

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39

Barbulée, Antoine, and Moussa Gomina. "Variability of the mechanical properties among flax fiber bundles and strands." Procedia Engineering 200 (2017): 487–93. http://dx.doi.org/10.1016/j.proeng.2017.07.068.

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40

Domenges, Bernadette, and Karine Charlet. "Direct Insights on Flax Fiber Structure by Focused Ion Beam Microscopy." Microscopy and Microanalysis 16, no. 2 (January 26, 2010): 175–82. http://dx.doi.org/10.1017/s1431927609991292.

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AbstractIn this article, it is shown that focused ion beam (FIB) systems can be used to study the inner structure of flax fibers, the use of which as a reinforcing material in polymer composites still draws much interest from multiple disciplines. This technique requires none of the specific preparations necessary for scanning electron microscopy or transmission electron microscopy studies. Irradiation experiments performed on FIB prepared cross sections with very low Ga+ion beam currents revealed the softer material components of fibers. Thus, it confirmed the presence of pectin-rich layers at the interfaces between the fibers of a bundle, but also allowed the precise localization of such layers within the secondary cell wall. Furthermore, it suggested new insights on the transition modes between the sublayers of the secondary cell wall.

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41

Manian, Avinash P., Michael Cordin, and Tung Pham. "Extraction of cellulose fibers from flax and hemp: a review." Cellulose 28, no. 13 (July 12, 2021): 8275–94. http://dx.doi.org/10.1007/s10570-021-04051-x.

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AbstractThe paper is a review on the extraction processes of cellulosic fibers from flax and hemp. The two lignocellulosic crops have a long history of use by humans for extraction of the bast fibers among other purposes. The utility of bast fibers declined over time with industrial advances and changes to the economy, but of late, with an increase of focus on environmental impact and sustainability, there is a renewed interest in these resources. The use of biomass-based resource requires an appreciation of plant anatomy and the agronomical variables in their cultivation and harvesting. This review provides an overview of these aspects as well as of the processes of retting for initial weakening of the plant structure in preparation for fiber extraction, degumming to isolate fiber bundles, and delignification.

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Jia, Yunlong, and Bodo Fiedler. "Influence of Furfuryl Alcohol Fiber Pre-Treatment on the Moisture Absorption and Mechanical Properties of Flax Fiber Composites." Fibers 6, no. 3 (August 19, 2018): 59. http://dx.doi.org/10.3390/fib6030059.

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Анотація:

Poor moisture resistance of natural fiber reinforced bio-composites is a major concern in structural applications. Many efforts have been devoted to alleviate degradation of bio-composites caused by moisture absorption. Among them, fiber pre-treatment has been proven to be effective. This paper proposes an alternative “green” fiber pretreatment with furfuryl alcohol. Pre-treatments with different parameters were performed and the influence on the mechanical properties of fiber bundles and composites was investigated. Moisture resistance of composites was evaluated by water absorption tests. Mechanical properties of composites with different water contents were analyzed in tensile tests. The results show that furfuryl alcohol pretreatment is a promising method to improve moisture resistance and mechanical properties (e.g., Young’s modulus increases up to 18%) of flax fiber composites.

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43

Prapavesis, Alexandros, Vedad Tojaga, Sören Östlund, and Aart Willem van Vuure. "Back calculated compressive properties of flax fibers utilizing the Impregnated Fiber Bundle Test (IFBT)." Composites Part A: Applied Science and Manufacturing 135 (August 2020): 105930. http://dx.doi.org/10.1016/j.compositesa.2020.105930.

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44

Robaszewska, Maria. "On some flat connection associated with locally symmetric surface." Annales Universitatis Paedagogicae Cracoviensis. Studia Mathematica 13, no. 1 (December 1, 2014): 19–43. http://dx.doi.org/10.2478/aupcsm-2014-0003.

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Abstract For every two-dimensional manifold M with locally symmetric linear connection ∇, endowed also with ∇-parallel volume element, we construct a flat connection on some principal fibre bundle P(M,G). Associated with - satisfying some particular conditions - local basis of TM local connection form of such a connection is an R(G)-valued 1-form build from the dual basis ω1, ω2 and from the local connection form ω of ▽. The structural equations of (M,∇) are equivalent to the condition dΩ-Ω∧Ω=0. This work was intended as an attempt to describe in a unified way the construction of similar 1-forms known for constant Gauss curvature surfaces, in particular of that given by R. Sasaki for pseudospherical surfaces.

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Akin, D. E., W. H. Morrison, G. R. Gamble, L. L. Rigsby, Gunnar Henriksson, and Karl-Erik L. Eriksson. "Effect of Retting Enzymes on the Structure and Composition of Flax Cell Walls." Textile Research Journal 67, no. 4 (April 1997): 279–87. http://dx.doi.org/10.1177/004051759706700407.

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Commercial enzyme mixtures are tested for their possibly selective degradation of flax ( Linum usitatissimum L.) stem components in relation to the retting process in producing linen. Structural and chemical compositional results from treatments are obtained using scanning electron microscopy, histochemistry, gas-liquid chromatography, 13C cp mas nmr spectrometry, and mid-infrared spectroscopy. Flaxzyme and Ultrazym and an enriched pectinase mixture (epm), which was not developed for flax retting but is included for comparison, are tested for their activity toward cell wall components and used in various concentrations for “enzyme-retting” of flax. Ariane flax stem sections are incubated with enzymes in a rotary incubator and the fibers are manually separated from the residual core. All of the commercial enzyme mixtures have cellulase, pectinase, and hemicellulase activities, but individual enzyme activities vary. Activities against the soluble test substrates do not predict the activity against natural fibers. At about equal protein concentrations, Flaxzyme treatment appears to facilitate bast fiber removal better than the other enzymes, with Ultrazym nearly as effective and epm the least effective. The ranking of effectiveness is generally supported by the amounts of uronic acid, arabinose, and xylose removed from the stems analyzed chemically. Increased enzyme levels generally facilitate removal of matrix carbohydrates from the flax. All enzymes separate bast fibers from the lignified core and partially from the cuticle near the cut surface of the stem sections, but the enzymes do not work far from the exposed ends. Retting quality is defined more by the degree of cell wall degradation and fiber separation than by any differences in kinds of cell walls degraded by the various enzymes. The cuticle remains attached to the fiber at times, apparently reducing access of the enzymes to the matrix polysacchrides and suggesting some recalcitrance of epidermal cells (and therefore loss of cuticle) to biodegradation. Lignin remains in the middle lamellae after enzyme retting and would likely prevent separation of the fiber bundles. Some solubilzation of the inner secondary wall of the flax fiber appears to occur with Flaxzyme. The structural and chemical analyses characterize alterations in flax bast after enzyme retting and would be useful in ranking the specificity and effectiveness of cell wall degradation.

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46

Banagl, Markus. "Isometric group actions and the cohomology of flat fiber bundles." Groups, Geometry, and Dynamics 7, no. 2 (2013): 293–321. http://dx.doi.org/10.4171/ggd/183.

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Song, Jifeng, Juntao Wang, Yisen Niu, Wenmo Wang, Kai Tong, Hai Yu, and Yongping Yang. "Flexible high flux solar simulator based on optical fiber bundles." Solar Energy 193 (November 2019): 576–83. http://dx.doi.org/10.1016/j.solener.2019.10.002.

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48

Grasso, Massimo, and Paolo Teofilatto. "Gauge theories, flat superforms and reduction of super fiber bundles." Reports on Mathematical Physics 25, no. 1 (February 1988): 53–71. http://dx.doi.org/10.1016/0034-4877(88)90042-0.

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49

CHEN, JINGYI. "SPECIAL LAGRANGIAN CYCLES AND HERMITIAN YANG–MILLS CONNECTIONS." Communications in Contemporary Mathematics 06, no. 01 (February 2004): 25–59. http://dx.doi.org/10.1142/s0219199704001227.

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We consider the adiabatic limit of a sequence of Hermitian Yang–Mills connections on a SU(r)-bundle over a semi-flat smooth special Lagrangian torus fibration π:M→B. The restriction of these connections to the fiber tori can be viewed as a family of SU(r)-connections on the fiber tori which are parameterized by B. We show that there is a gauge equivalent subsequence such that the restriction of each connection to the fiber tori converges in the Hausdorff topology, away from some closed subset of B of codimension at least two, to a limit which defines a r-sheeted special Lagrangian cycle in the dual special Lagrangian torus fibration.

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Leyman, Viviane, Piet Stoffelen, Sofie De Smedt, and Ann Bogaerts. "Fibres in Meise Botanic Garden: A Future for Heritage Collections?" Biodiversity Information Science and Standards 2 (June 13, 2018): e26663. http://dx.doi.org/10.3897/biss.2.26663.

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Анотація:

The precious historical collection of fibres in Meise Botanic Garden, with over 500 specimens in old hand-blown glass jars, was rehabilitated in 2017. Most of the specimens date back to the second half of the 19th century, a period of technological revolution. The rehabilitation retraces the industrious search for every possible raw material provided by nature at that time. The result is astonishing, not only regarding the origin and quality of the preserved material, its label information and its accompanying manuscripts, but also because of the extremely wide range of fibre species and their processing. Noted collectors enriching our collections were, inter alios, the Josephite Brother Bernardin of Melle (Belgium), Carl von Martius and his brother Theodor Martius of Erlangen (Germany) and Henri Van Heurck of Antwerp (Belgium). Famous museums and botanic gardens such as the Museum of French Colonies in Paris (France) and the Experimental Garden in Eala (Democratic Republic of the Congo DRC) were also important suppliers. Samples originate from all over the world with strong representation from India, the DRC and Brazil. The nature of the fibres in the collection is very diverse and ranges from stem, bark and leaf fibres to husk fibres and seed hairs. Some of them have been processed into bundles and braids, beaten bark, spun thread and twined rope, as well as rough or organza-like fabrics. Even plant pith, pulp and paper are included, next to silkworm silk and mineral tremolite (a form of asbestos). Not only are familiar plant fibres such as cotton, sisal, ramie, coir, flax and jute present, but also Congo jute, Cuban bast, lacebark, piassava, esparto, fern wool, fibres of linden, sunflower, banana and pineapple, next to different types of paper and bark cloth. More than a hundred genera appear. Dominant families in terms of specimen numbers are Malvaceae (including Tiliaceae), Liliaceae (including Agavaceae), Palmae, Urticaceae, Bombacaceae, Musaceae and Gramineae. This upgraded collection exhibits an unexpected data diversity and consequently offers multitudinous possibilities for innovative research. One of our mission statements is undoubtedly: safeguarding historical collections for the future.

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