Articoli di riviste: "Fibrés de Procesi"

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Harizi, T., S. Dhouib, S. Msahli e F. Sakli. "Bleaching Process Investigation of Tunisian Dromedary Hair". ISRN Textiles 2013 (4 giugno 2013): 1–5. http://dx.doi.org/10.1155/2013/532396.

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Successful bleaching of pigmented fibres was, generally, evaluated by a maximum whiteness, a minimum yellowness, and less damage to the bleached fibers. A review of the literature reveals that many studies on pigmented fibre bleaching are concerned with improving the whiteness and mechanical properties of bleached fibres. In this study, we investigate the effects of the hydrogen peroxide concentration, bleaching time, and clarification bath on the bleaching efficiency of Tunisian dromedary hair. It was showed that 30 min bleaching time gives better result in term of whiteness. However, an increased bleaching time gives an excessive damage to the bleached fibers. Further, the damage incurred by the dromedary hair was more important than that for wool, as is shown by the tenacity results. We found that oxalic acid, which is used for rinsing dromedary hair (after bleaching), provides improved results in term of whiteness obtained with bleaching. Certainly, oxalic acid made it possible to remove the maximum of iron remaining on fibre after bleaching. Bleaching methods demonstrate the excessive damage incurred by the fibre when using hydrogen peroxide particularly with raise concentration. This damage leads to adverse effects on the tenacity fibre.

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Swaroop, Dasagrandhi Veda. "Analysis of Mechanical Properties of Banana-Jute Hybrid Fiber-reinforced Epoxy composite by varying Stacking sequence". International Journal for Research in Applied Science and Engineering Technology 10, n. 3 (31 marzo 2022): 429–38. http://dx.doi.org/10.22214/ijraset.2022.40581.

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Abstract: Nowadays, the study on natural fibers has gradually increased because of the environmental concerns due to usage of synthetic fibers. The natural fibres properties such as biodegradability, availability, strength made them a potential replacement of synthetic fibers. Hybrid Fibre reinforced composites are the composites that comprises two or more different fibres. The banana and jute fibres are selected because of their strength, moisture absorption capacity , availability. The epoxy resin is selected as a matrix to bind the fibres and to transfer a uniform load. Banana-Jute Hybrid fibre reinforced epoxy composite with different stacking sequences (BJB, BBJ, JBJ,JJB where B=Banana Fibre, J=Jute Fibre) will be fabricated by Hand-layup process for analyzing Shore hardness of composite samples and the same composite samples will be modelled in ANSYS to analyse the Flexural properties, tensile properties and Impact strength of composite samples. Keywords: ANSYS, Hand-layup, Shore Hardness, Flexural properties, Tensile properties.

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Yatsenko, T. A., V. М. Rybachuk, O. I. Yusova, S. M. Kharchenko e T. V. Grinenko. "Effect of fibrin degradation products on fibrinolytic process". Ukrainian Biochemical Journal 88, n. 2 (25 aprile 2016): 16–24. http://dx.doi.org/10.15407/ubj88.02.016.

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Zhang, Wei, Xu Wang e Hong Wei Xing. "Numerical Simulation of the Cooling Process of the Blast Furnace Slag Fiber". Advanced Materials Research 934 (maggio 2014): 223–29. http://dx.doi.org/10.4028/www.scientific.net/amr.934.223.

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The cooling process of the blast furnace slag fibers was simulated and calculated by the numerical simulation software. The different length-diameter ratio fibers for 100:1 and 1000:1 were chosen and the temperature fields of the fibers cooling process under the different conditions were analyzed. The results showed that the single fiber’s solidification has begun at 0.1s, the fiber forms the whole shell on its surface at 0.9s, and the center of the fiber become solid at about 1.5s. Multi-fibers cooling process is different from the single fiber and the solidification time obviously become longer. 3-fibers’ solidification performs began at about 0.1s, and the whole solidification process needs about 5s.

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Wójcik, Grzegorz Michał. "Optimization of silica glass capillary and rods drawing process." Photonics Letters of Poland 11, n. 1 (3 aprile 2019): 19. http://dx.doi.org/10.4302/plp.v11i1.891.

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Diameter fluctuations of silica glass rods and capillaries, during drawing process have been studied. We investigated an influence of drawing conditions on the quality of capillaries and rods. We fabricated two preforms made from different quality material. Fabricated preforms were used to draw microstructured fibers. Full Text: PDF ReferencesS. Habib et al., "Broadband dispersion compensation of conventional single mode fibers using microstructure optical fibers", Int. J. Lig. Opt. 124, 3851-3855 (2013) CrossRef A. Ziolowicz et al. "Overcoming the capacity crunch: ITU-T G.657.B3 compatible 7-core and 19-core hole-assisted fibers", Proc SPIE 10130, 101300C (2017) CrossRef T.M. Monro et al. "Sensing with microstructured optical fibres", Meas. Sci. Technol. 12, 854-858 (2001) CrossRef G. Statkiewicz-Barabach et al.,"Hydrostatic Pressure and Temperature Measurements Using an In-Line Mach-Zehnder Interferometer Based on a Two-Mode Highly Birefringent Microstructured Fiber", Sensors 2017, 17, 1648 (2017) CrossRef T. Yoon, M. Bajcsy, "Laser-cooled cesium atoms confined with a magic-wavelength dipole trap inside a hollow-core photonic-bandgap fiber", Phys. Rev. A 99, 023415 (2019) CrossRef A.N. Ghosh et al., "Supercontinuum generation in heavy-metal oxide glass based suspended-core photonic crystal fibers", J. Opt. Soc. Am. B 35, 2311-2316 (2018) CrossRef G. Wójcik et al. "Microbending losses in optical fibers with different cross-sections", Proc. SPIE 10830, 108300H (2018) CrossRef F. Xu, Selected topics on optical fiber technology and applications (IntechOpen 2018) CrossRef

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Hernández, J. B., F. A. Aguirre, J. L. Martínez, C. E. Caballero, L. Pérez-Rea e V. M. Castaño. "Dielectric Dissipation of Fibre-modified Hydraulic Concretes". Advanced Composites Letters 7, n. 6 (novembre 1998): 096369359800700. http://dx.doi.org/10.1177/096369359800700603.

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Dielectric behavior of Portland cement-based concretes, modified with either polyester or polypropylene fibers was studied by measuring their dissipation factors at different frequencies. The results show that the fibers with non-polar surfaces (polyester) do not influence the hydration process of the cement matrix, whereas polypropylene fibres, with polar surfaces, have a definitive role on the curing properties of the composites.

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Davindrabrabu, Mathivanan, Parlaungan Siregar Januar, Bachtiar Dandi, Mat Rejab Mohd Ruzaimi e Tezara Cionita. "Effect of Fibre Loading on the Flexural Properties of Natural Fibre Reinforced Polymer Composites". Applied Mechanics and Materials 695 (novembre 2014): 85–88. http://dx.doi.org/10.4028/www.scientific.net/amm.695.85.

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The use of pineapple leaf fibres as reinforcement in plastics had increased rapidly in past few years. Thus this project was conducted to determine and compare the flexural strength of pure epoxy and pineapple leaf fibres reinforced epoxy. The natural fibres were mixed with epoxy and hardener by weight percentage fibre content. The process employed to fabricate the specimens was hand lay-up and the natural fibres was oriented randomly. The dimensions of the specimens for flexure test were based on ASTM D790 respectively. The results obtained shows that 15% PALF reinforced epoxy composite achieved the highest flexural strength among the natural fibers reinforced epoxy composites.

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Hery Sunarsono, Hazimah, Sari Rahmiati, Mohd Sapuan Salit, Ahmad Ilyas Rushdan e Fiqri Ardi Azhari. "Effect of Various Concentrations of Sodium Hydroxide/Hot Alkali Treatment on the Physical Properties of Ramie Fibres". Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 115, n. 2 (1 aprile 2024): 96–102. http://dx.doi.org/10.37934/arfmts.115.2.96102.

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The preparation stages that precede the final treatment with a chemical treatment like alkali determine the physical characteristics of ramie fibres. It modified the hydroxyl group which is responsible for the hydrogen bonding of the fibres. This work examined the pre-treatment of ramie fibres with acetone followed by alkali or hot alkali with various concentrations. The immersion of ramie fibres in certain percentages of sodium hydroxide solution resulted in a good performance of their physical characteristics. The ramie fibres treated with 10% NaOH exhibit the best dispersion stability and low agglomeration or precipitation in water with an amount of 14%. When alkali is applied to ramie fibres, the hydrophilic group on their surface grows, potentially improving the fibre's capacity to absorb water. However, when the concentration is increased to 15%, the dispersion stability of sodium hydroxide performs less well. The fibres' ability to absorb water was diminished and they became brittle due to a high alkali content. In addition to the aforementioned characteristics, the properties of precipitation and water absorption were unaffected by the hot alkaline process for all samples. The hot alkali process (80°C) was not able to generate a further breakdown of hydrogen bonds of the fibres.

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ZHU, Sufeng, Zenghui ZHAO, Yinping YUE, Xufeng DONG e Min QI. "Influence of the Chemical Modification of Carbon Nanotube Fibers on Electrical properties and Electromechanical Response". Progress in Chinese Materials Sciences 3, n. 2 (28 giugno 2024): 20–28. http://dx.doi.org/10.48014/pcms.20240218001.

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The electromechanical response (EMR) of carbon nanotube (CNT) fibers is related to the densification process of the CNT network driven by electromagnetic force. The study of the interaction between the electrical properties and the electromechanical response of carbon nanotubes is of great theoretical significance for exploring the microstructure of carbon nanotube fibers and developing the related flexible electronic devices. This study investigated the relationship between the conductive pathway network and EMR, by analyzing the internal structural characteristics of the CNT fibers after undergoing hydrogen peroxide oxidation and iodine modification. The results show that impurities such as amorphous carbon impeded electron transport and deformation of CNT networks. After hydrogen peroxide oxidation treatment, he carbon nanotube surface impurities inside the fibres were reduced, the van der Waals forces between carbon nanotubes were increased, the deformation of the carbon nanotube network was enhanced, and the negative effect of the decrease in the elastic modulus of the fibres caused by the increase in temperature was weakened. In the case of iodine-decorated CNT fibers, carbon-iodine bonds effectively strengthened the interaction between CNTs, but hinders the contraction of the carbon nanotube network, resulting in a weaker electromechanical response. Hydrogen peroxide oxidation treatment is more beneficial than iodine modification to improve the shrinkage and deformation ability of carbon nanotube fibres in the electromechanical response.

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Perelles, D. H., M. F. Medeiros e M. R. Garcez. "Aplicação da análise hierárquica como ferramenta de tomada de decisão para escolha do compósito de reforço com polímeros reforçados com fibras". Revista ALCONPAT 3, n. 3 (30 settembre 2013): 161–76. http://dx.doi.org/10.21041/ra.v3i3.52.

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RESUMOO reforço de estruturas com Polímeros Reforçados com Fibras (PRF) é uma alternativa que tem sido muito utilizada em intervenções executadas em elementos de concreto armado. A fibra de carbono é a mais empregada na formação dos compósitos de reforço utilizados em obras civis. Existe, no entanto, a possibilidade de se ampliar as opções de fibras formadoras do compósito utilizando as fibras de aramida e de vidro. Como uma ferramenta alternativa de tomada de decisão, o Método de Análise Hierárquica, baseado em critérios analisados de forma qualitativa e quantitativa, será utilizado neste trabalho para a avaliação das fibras de carbono, aramida e vidro, de forma a se obter qual material seria o mais apropriado para a execução de um reforço estrutural considerando como principais parâmetros de análise os custos dos materiais e as tensões e as deformações que os elementos poderão apresentar. A aplicação desta técnica de interpretação de resultados se mostrou muito útil, podendo ser considerada adequada para estudos que exijam uma tomada de decisão entre diferentes sistemas de reforço com PRF.Palabras clave: Reforço estrutural; polímeros reforçados com fibras; carbono; aramida; vidro; método da análise hierárquica.ABSTRACTStrengthening structures with Fiber Reinforced Polymers (FRP) is an alternative that has been used in interventions performed on reinforced concrete elements. Carbon fibers are the most used in the formation of composite reinforcement used in civil works. There is, however, possible to expand the options of forming fibers using the composite fibers of aramid and glass. As an alternative decision-making tool, the Analytic Hierarchy Process, based on criteria analyzed qualitatively and quantitatively, will be used in this work for the evaluation of carbon, aramid and glass fibers in order to obtain what material would be more suitable for the implementation of a structural reinforcement considering how key parameters of analysis material costs and the tensions and strains that may exhibit elements. This decision-making tool showed useful and can be considered suitable to select different FRP systems.Keywords: Structural strengthening; fiber-reinforced polymers; carbon; aramid; glass; hierarchical analysis method.

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Carrillo, F., J. Valldeperas, D. Evans, M. Huson e X. Colom. "Influencia del proceso de fibrilación y desfibrilación enzimática en las propiedades mecánicas de hilos de fibras celulósicas regeneradas obtenidas por el proceso NMMO". Revista de Metalurgia 37, n. 2 (30 aprile 2001): 348–51. http://dx.doi.org/10.3989/revmetalm.2001.v37.i2.494.

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Bindal, Amit, Satnam Singh, N. K. Batra e Rajesh Khanna. "Development of Glass/Jute Fibers Reinforced Polyester Composite". Indian Journal of Materials Science 2013 (11 novembre 2013): 1–6. http://dx.doi.org/10.1155/2013/675264.

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Composites play significant role as engineering material and their use has been increasing day by day due to their specific properties such as high strength to weight ratios, high modulus to weight ratio, corrosion resistance, and wear resistance. In present work, an attempt is made to hybridize the material using synthetic (glass) as well as natural fibres (chemically treated jute), such that to reduce the overall use of synthetic reinforcement, to reduce the overall cost, and to enhance the mechanical properties. All composite specimens with different weight percentages of fibres were manufactured using hand lay-up process and testing was done by using ASTM standards. Experimental results revealed that hybridization of composite with natural and synthetic fibres shows enhanced tensile strength, flexural strength, and impact strength. The content of natural reinforcement was found to be in the range of 25–33.3% for best results. The effect of treated jute on flexural properties was more than that on tensile properties, which was due to greater stiffness of jute fibers. Chemical treatment of jute fibers lowers the water absorption and results were comparable to glass fiber reinforced polyester composites. The addition of jute also reduced the overall cost by 22.18%.

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Yang, Zhi Yuan, Hai Zhen Shi e 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 (marzo 2012): 67–70. http://dx.doi.org/10.4028/www.scientific.net/amr.496.67.

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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.

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Liu, Xiao Dong, Xiao Gang Bai e Zhuo Zhang. "Thermal Stability of the Hemp Fibers and Fabrics". Advanced Materials Research 466-467 (febbraio 2012): 152–56. http://dx.doi.org/10.4028/www.scientific.net/amr.466-467.152.

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With the thermal gravity analysis and relative breaking strength test, both crystallization variability and the important temperature is determined in heating process of hemp fibers. Meanwhile, the critical time and temperature is got which have a effect on relative breaking strength of hemp fibres and the hemp fabric appearance. Those data about thermal stability is helpful for hemp manufacturing and processing.

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Pisarenko, Tatiana, Nikola Papež, Dinara Sobola, Ştefan Ţălu, Klára Částková, Pavel Škarvada, Robert Macků, Erik Ščasnovič e Jaroslav Kaštyl. "Comprehensive Characterization of PVDF Nanofibers at Macro- and Nanolevel". Polymers 14, n. 3 (1 febbraio 2022): 593. http://dx.doi.org/10.3390/polym14030593.

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This study is focused on the characterization and investigation of polyvinylidene fluoride (PVDF) nanofibers from the point of view of macro- and nanometer level. The fibers were produced using electrostatic spinning process in air. Two types of fibers were produced since the collector speed (300 rpm and 2000 rpm) differed as the only one processing parameter. Differences in fiber’s properties were studied by scanning electron microscopy (SEM) with cross-sections observation utilizing focused ion beam (FIB). The phase composition was determined by Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy. The crystallinity was determined by differential scanning calorimetry (DSC), and chemical analysis of fiber’s surfaces and bonding states were studied using X-ray photoelectron spectroscopy (XPS). Other methods, such as atomic force microscopy (AFM) and piezoelectric force microscopy (PFM), were employed to describe morphology and piezoelectric response of single fiber, respectively. Moreover, the wetting behavior (hydrophobicity or hydrophilicity) was also studied. It was found that collector speed significantly affects fibers alignment and wettability (directionally ordered fibers produced at 2000 rpm almost super-hydrophobic in comparison with disordered fibers spun at 300 rpm with hydrophilic behavior) as properties at macrolevel. However, it was confirmed that these differences at the macrolevel are closely connected and originate from nanolevel attributes. The study of single individual fibers revealed some protrusions on the fiber’s surface, and fibers spun at 300 rpm had a core-shell design, while fibers spun at 2000 rpm were hollow.

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Lüking, Alexander, Robert Brüll, Thomas Köhler, Davide Pico, Gunnar Seide e Thomas Gries. "One Step Production of Bicomponent Yarns with Glass Fibre Core and Thermoplastic Sheath for Composite Applications". Key Engineering Materials 742 (luglio 2017): 506–11. http://dx.doi.org/10.4028/www.scientific.net/kem.742.506.

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The film stacking method is the industrial standard for the manufacturing of fibre reinforced thermoplastic composites (FRTCs). An alternative to this is commingling thermoplastic fibres with reinforcement fibres, e. g. glass fibres, into hybrid yarns. However, the composites produced by the use of film-stacking or hybrid yarns cannot achieve an optimal impregnation of reinforcement fibres with the matrix polymer. This stens from the high melt viscosity of thermoplastics, which prevents a uniform wetting of the reinforcement fibres. Leaving some fibers is unconnected to the matrix. This leads to composite lower strength than theoretically possible. The aim of the research is the coating of a single glass filament in the glass fibre nozzle drawing process to achive a homogenous distribution of glass fibres and matrix in the final composite. The approach uses particles with a diameter from 5 to 25 μm of polyamide 12 (PA 12) which are electrostatically charged and blown at an Eglass filament in the nozzle drawing process as seen in. The particles adhering to the filament are melted by infrared heating and winded afterwards. This development will allow the homogenous distribution of fibres and the matrix in a thermoplastic composite allowing a higher fibre volume content leading to improved mechanical properties. Even though the glass filaments could be coated with PA 12, a homogenous sheath could not be achieved in this investigation. Therefore, further research will focus on an improved homogeneity by reducing the agglomeration of PA 12, using dried PA12 and enhancing the coating setup.

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Ba, X., Y. Meng, Y. Huang, S. Y. Kwak, S. Ge, Y. Qin, E. DiMasi, Helga Füredi-Milhofer, N. Pernodet e Miriam Rafailovich. "In Vitro Biomineralization Induced by Self-Assembled Extracellular Matrix Proteins". Key Engineering Materials 361-363 (novembre 2007): 427–30. http://dx.doi.org/10.4028/www.scientific.net/kem.361-363.427.

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Extracellular matrix (ECM) proteins play an essential role during biomineralization in bone and engineered tissues. In a previous study [1], we showed that calcite preferentially nucleated on pure elastin fibers. However, the actual cellular ECM fibers are composed of a combination of proteins, primarily collagen, fibronectin and some elastin. Here we follow the calcium carbonate- and calcium phosphate- mineralization process in vitro when these ECM proteins are combined and determine the differences between these proteins in the biomineralization process. The surface morphology and mechanical properties of the protein fibers during the early stages were probed by atomic force microscopy (AFM) and shear modulation force microscopy (SMFM). The nucleation of the mineral crystals on the protein matrices was investigated by scanning electron microscopy (SEM). Preliminary data showed that the moduli of all protein fibers increased at the early stages, with collagen having the largest increase in supersaturated calcium bicarbonate solution. In metastable calcium phosphate solutions the modulus of the mixed elastin-fibronectin fibres increased to a greater extent than the moduli of the fibers composed of the single proteins. Longer exposure in the mineral solutions led to the formation of crystals templated along the self-assembled fiber structures.

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Ferrari, V. J., A. P. Arquez e J. B. De Hanai. "Compósitos cimentícios de alto desempenho para aplicação como substrato de transição em vigas". Revista ALCONPAT 6, n. 1 (16 marzo 2016): 52–63. http://dx.doi.org/10.21041/ra.v6i1.115.

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Compuestos cementíceos de alto desempeño para su aplicación como sustrato de transición en vigasRESUMENEste estudio muestra el desarrollo y análisis del comportamiento de los materiales compuestos de cemento reforzado con fibras de alto rendimiento. El material descrito se desarrolló específicamente para su aplicación como sustrato de transición, o capa de reparación de la formación de la brida tensada vigas de hormigón reforzado con polímeros de flexión reforzado con fibras de carbono (PRFC). Diecinueve compuestos diferentes fueron producidos por el proceso de hibridación. Se varió la cantidad de fibras cortas y microfibras de acero. Para analizar el comportamiento de los ensayos de flexión en tres puntos materiales prismas se realizaron Jagged. La respuesta del material se analizó teniendo en cuenta parámetros de tenacidad a la flexión y (fractura). Materiales compuestos de alto rendimiento evidencia a través de un comportamiento pseudo- endurecimiento.Palabras clave: compuestos cementíceos; vigas de concreto; sustrato de transición. High performance cementitious compounds and their application as transition substrate for beamsABSTRACTThis study presents the development and analysis of the behavior of high performance cementitious compounds reinforced with fibers. The material described was specifically developed for its application as a transition substrate, meaning, a repair layer that forms the tensed span of the flexion reinforced concrete beams with carbon fiber reinforced polymers (CFRP). Nineteen different compounds were produced by the hybridization process. The volume of the short fibers and of the steel microfibers varied. To analyze the behavior of the flexural material, tests were done in three points in tests tubes with their notches. The response of the material was analyzed considering the tenacity parameters (to flexion and fracture). The high performance of the compounds through the behavior of pseudo-hardening was confirmed.Keywords: cementitious compounds; concrete beams; transition substrate. Compósitos cimentícios de alto desempenho para aplicação como substrato de transição em vigasRESUMONeste estudo apresenta-se o desenvolvimento e a análise do comportamiento de compuestos cementíceos de elevado desempeño reforzados com fibras. O material descrito foi especificamente desarrollado para aplicación como um sustrato de transición, ou seja, camada de reparo que forma o banzo traccionado de vigas de concreto reforçadas à flexão com polímeros reforzados com fibras de carbono (PRFC). Dezenove diferentes compuestos foram produzidos pelo processo de hibridização. Variou-se o volume de fibras curtas e de microfibras de aço. Para analisar o comportamiento do material à flexão, ensaios em três pontos em prismas entalhados foram realizados. A resposta do material foi analisada considerando-se parâmetros de tenacidade (flexional e ao fraturamento). Ficou evidenciado o elevado desempeño dos compuestos através de comportamiento de pseudo-encruamento.Palavras-chave: compuestos cementíceos; vigas de concreto; sustrato de transición.

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Yoshida, K., T. Satoh, N. Enomoto, H. Hihara, T. Yagi e M. Oku. "Hybridised fabrication process for optical fibres". Electronics Letters 32, n. 3 (1996): 242. http://dx.doi.org/10.1049/el:19960149.

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Komatsu, T. "Fracture process of superdrawn polyoxymethylene fibres". Journal of Materials Science 28, n. 11 (1 gennaio 1993): 3035–42. http://dx.doi.org/10.1007/bf00354709.

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Abdullah, Abdul Hakim, Faris Firdaus Abdul Mutalib e Muhd Faiz Mat. "Tensile and Fracture Toughness Properties of Coconut Spathe Fibre Reinforced Epoxy Composites: Effect of Chemical Treatments". Advanced Materials Research 1133 (gennaio 2016): 603–7. http://dx.doi.org/10.4028/www.scientific.net/amr.1133.603.

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Natural fibres are considered as a potential replacement for man-made fibers in composite materials because of their advantages over other established materials. However, serious problem of natural fibres is their strong polar character which creates incompatibility with most polymer matrices. In present investigation, the effect of alkaline, silane and combination of both treatments is investigated. Tensile properties and fracture toughness of coconut spathe fibre for untreated and treated were evaluated. Samples were fabricated by using the hand layup process. Result indicated that silane treatment has achieved a better performance for the tensile test while there is none improvement fracture toughness was displayed by silane or alkaline treatment as compared to untreated fibres. The alkaline treatment showed to be harmful for fracture toughness of the coconut spathe fibre since the improved interfacial adhesion impaired the main energy absorption mechanisms. Keyword: Composites, Coconut Spathe Fibre, Alkaline and Silance Treatment

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Ardanuy, Mònica, Josep Claramunt, Raquel Arévalo, Ferran Parés, Elisabetta Aracri e Teresa Vidal. "Nanofibrillated cellulose (NFC) as a potential reinforcement for high performance cement mortar composites". BioResources 7, n. 3 (9 luglio 2012): 3883–94. http://dx.doi.org/10.15376/biores.7.3.3883-3894.

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In this work, nanofibrillated cellulose (NFC) has been evaluated as a potential reinforcement for cement mortar composites. Two types of vegetable fibres with different composition and properties (cellulose content and microfibrillar angle), sisal, and cotton linters pulps, were initially characterised in order to assess their reinforcing capability. Sisal pulp was found to be most suitable as reinforcement for the brittle cementitious matrix. Nanofibrillated cellulose was produced by the application of a high intensity refining process of the sisal pulp. It was found that 6 hours of refining time was required to obtain the desired nanofibrillation of the fibers. Cement mortar composites reinforced with both the sisal fibres and the nanofibrillated cellulose were prepared, and the mechanical properties were determined under flexural tests. The cement mortar composites reinforced with the nanofibrillated cellulose exhibited enhanced flexural properties, but lower values of fracture energy, than the ones reinforced with the conventional sisal fibres.

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Hofmann, Marcel, Dirk Wenzel, Bernd Gulich, Heike Illing-Günther e Daisy Nestler. "Development of Nonwoven Preforms Made of Pure Recycled Carbon Fibres (rCF) for Applications of Composite Materials". Key Engineering Materials 742 (luglio 2017): 555–61. http://dx.doi.org/10.4028/www.scientific.net/kem.742.555.

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For the development of an efficient and economic recycling process of carbon fibers (CF) still many technological challenges have to be mastered. One of them is the removal of all extraneous natural and synthetic fibres, e.g. polyester sewing threads. The objective of the research was to develop an in-line process for the removal of those extraneous fibres, which result from mechanical processes such as tearing. A promising approach for the removal of extraneous fibres from cut-off carbon-fibre material (CF) has been identified, getting recycled carbon fibres (rCF). For that purpose, the use of modern laser technologies is particularly promising. However, the focus was not the development of new laser systems, but the adaptation of existing technologies and their integration into textile processing steps for carbon fibre recycling. In addition to the removal of the extraneous fibres, the degree of CF losses and quality degradation due to fibre damage have been analysed and compared with optimum fibre characteristics. The separation has been experimented and corresponding laser parameters have been defined. Finally, the obtained carbon-fibre material has been tested with regard to its processability in textile manufacturing processes (dry non-woven fabric production) up to carbon fibre reinforced plastics (CFRP). For the evaluation of the material for potential applications, test plates from irradiated and non-irradiated material have been used. The performed tensile and flexural tests have proved that the irradiated material has similar properties compared to the non-exposed one.

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24

Seile, Arta, e Dana Beļakova. "NONWOVEN DEVELOPMENT BY THE MULTILAYER STRUCTURE". Environment. Technology. Resources. Proceedings of the International Scientific and Practical Conference 3 (15 giugno 2017): 292. http://dx.doi.org/10.17770/etr2017vol3.2612.

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The main two directives of the European Commission (EC) has been regulating the automotive industry. The aforementioned directives and education of residents on environmental issues has created the need for new materials that have been produced from renewable resources and should be recycled at the end of product life cycle. The objective of this project is to develop a nonwoven materials (NWM) that would incorporate fibers of plants, which could be grown in Latvia because of suitable local climate conditions, for the use in automotive industry. Furthermore, inclusion of polymer fibers in the NWM will expand the areas of use of such material – the NWM can be transformed into a composite material by means of a thermal press. Manufacturing process of NWM consist of structure modelling and material samples manufacturing. NWM samples production process to be carried out by fibers preparation, fibers mixing, formation by airlaid method, preparation of fiber webs for fixation with a mechanical needle punching method, mechanical fixation of fiber webs, preparation of fixed fiber webs for NWM manufacturing and manufacturing of NWM by mechanical needle punching method. This article reflects the comparison of two compositions NMW (Polylactid (PLA) (60 wt%) and long flax fibres (40 wt%), and PLA (60 wt%) and technical hemp fibres (40 wt%)) with the same structure by visual appearance, geometrical parameters and tensile strength. The average surface density of hemp NWM varies in the range of 792.09 to 958,71 g•m−2 , thickness varies from 6.91 to 9.23 mm. Flax NWM average surface density is higher than hemp NWM and varies in range of 1,064 to 1,260 g•m−2, thickness of the material varies from 12.62 to 15.54 mm. For comparison, the surface density of NWM currently used in automotive industry, depending on the use of the material, varies from 100 to 1,400 g•m−2.

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25

Namozovich, Karshiyev Olim. "Dynamics Of Change Of Seed Fluff After Germination Process". American Journal of Applied sciences 02, n. 12 (31 dicembre 2020): 170–76. http://dx.doi.org/10.37547/tajas/volume02issue12-26.

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Abstract (sommario):

Residual fiber in the fiber-separated seeds reduces the efficiency of fluff separation in linter machines, and the process of fluff separation is disrupted as a result of the clogging of the fibers into the saw teeth. Therefore, theoretical, practical research and creation of a device for separation of fibers from residual fluffy seeds before the lintering process is relevant.

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26

Xue, P., Xiao Ming Tao e Keun Hoo Park. "Electrically Conductive Fibers/Yarns with Sensing Behavior from PVA and Carbon Black". Key Engineering Materials 462-463 (gennaio 2011): 18–23. http://dx.doi.org/10.4028/www.scientific.net/kem.462-463.18.

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Abstract (sommario):

In this study, electrical conductive yarns were prepared by wet-spinning technique and a physically coating process. Carbon black (CB) was used to make the fiber gaining electrical conductivity. The electrical conductivity and morphological characteristics of the developed conductive fibres were studied and compared. The results show that linear resistivity of the produced conductive yarns ranges from 1 to a few hundred kΩ per centimeter, mainly depending on processing technique and substrate fibers. It is also shown that the physically coating processes will not significantly affect the mechanical properties of the fibers and yarns. These conductive yarns are lightweight, durable, flexible, and cost competitive; and able to be crimped and subjected to textile processing without any difficulty.

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27

MULDASHEVA, G. K., I. V. ZLOBINA e N. V. BEKRENEV. "FEATURES OF CHIP FORMATION DURING ULTRASONIC DRILLING OF CARBON FIBER PLASTICS". IZVESTIA VOLGOGRAD STATE TECHNICAL UNIVERSITY, n. 8(279) (settembre 2023): 29–31. http://dx.doi.org/10.35211/1990-5297-2023-8-279-29-31.

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Abstract (sommario):

The article is devoted to the description of chip formation during ultrasonic drilling of small diameter holes in structural carbon fiber. Established that generated when drilling with ultrasound chip is qualitatively different from the chip during normal drilling less compartilhamento and the presence of truncated fragments of carbon fibres, reflecting greater uniformity of the cutting process and to facilitate chip evacuation and describes the possibility of increasing the quality of processing by reducing the number of surviving unidirectional fibers.

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28

Nwaiwu, Cajetan O., Jervas Ekezie, Oladimeji Taofik Azeez, Ada Jovita Daniel, Oluchi Blessing Igbokwe e Magdalene Nkeiru Akanbi. "Optimization, Sodium Hydroxide and Plantain Fibres: Mechanical Properties of Unsaturated Polyester Composites for Transtibial Prosthetic Socket". Key Engineering Materials 981 (14 maggio 2024): 165–76. http://dx.doi.org/10.4028/p-gx7c9i.

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Abstract (sommario):

Low mechanical behaviors of natural fibres in the reinforcement of polymer composites have remain an issue of concern. This study is aimed at investigating the effect of NaOH treatment on the mechanical properties of plantain fiber for the transtibial prosthetic sockets made of polyester resin. Plantain fiber was extracted from the plantain bast using water retting techniques. The fibres were modified using alkaline treatment method of 5 – 25% for variable time of 30 to 150 minutes. It was optimized using 3-level Factorial design (3-LCD) of response surface methodology based on tensile properties of treated fibres. The polyester composites of plantain and glass fibers were prepared using hand-layup techniques. Instron Universal testing machine-3369 model was used to determine the tensile and impact properties of fibers and polyester composites. Rockwell hardness tester-RBHT/S-39 model was used to determine the hardness property. The optimum process conditions of 5 % NaOH for 119 minutes improved plantain fiber tensile strength, modulus, strain, energy, and extension by improved by 102.03, 208.07, 9.70, 210.52 and 205.73 %, respectively. The ultimate tensile strength and modulus was obtained at 10 and 12.5% fiber loading. The hardness and impact strength of NaOH modified unsaturated polyester composites was marginally more than 3.51 and 10.69% of glass fiber reinforced unsaturated composites, respectively, at 12.5% fiber loading. FTIR analysis revealed the improvement in mechanical properties. Thus, NaOH modified plantain fiber unsaturated polyester composites serves as a better alternative for making transtibial prosthetic socket.

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29

Zhang, Yuan Song, Ji Xiang Xie e Yu Chun Jiang. "Study on Division of Natural Bamboo Fibers by Steam Explosion". Advanced Materials Research 476-478 (febbraio 2012): 1873–76. http://dx.doi.org/10.4028/www.scientific.net/amr.476-478.1873.

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Abstract (sommario):

In order to improve the effect of natural bamboo fibers degumming, the factors affecting the natural bamboo fibers separation effect in general alkali boiling conditions after the process of steam explosion were researched. The results showed that the degumming rate increased with the rise of steam explosion pressure and the pressure maintaining time. As the steam explosion was stronger, the degree of the fibers separation and softness were better. After steam explosion and alkali boiling united degumming method, the hemicelluloses and lignin content of the fibers decreased by 41.61% and 31.94%, while the cellulose content rose to 63.59%. The effect of steam explosion and alkali boiling united degumming method was better than single alkali boiling or steam explosion. The morphology of fibers became smooth and the fiber’s diameter reduced obviously.

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30

Szczepanik, Ewa, Piotr Szatkowski, Edyta Molik e Kinga Pielichowska. "The Effect of Natural Plant and Animal Fibres on PLA Composites Degradation Process". Applied Sciences 14, n. 13 (27 giugno 2024): 5600. http://dx.doi.org/10.3390/app14135600.

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Abstract (sommario):

One of the methods to reduce long-term excessive plastic waste is the development and use of composite materials based on biodegradable polymers and natural fibres. Composites with natural fibres can exhibit very good mechanical properties, and the presence of natural fibres can significantly accelerate the degradation of the material. This study aimed to manufacture and analyse the biodegradation process of composites based on biodegradable polylactide (PLA) filled with flax and sheep wool fibres. The effect of flax and wool fibres and their content on the degradation rate compared to that of pure PLA was investigated. The degradation progress and properties of the composites were studied using an optical microscope, SEM, measurement of surface roughness, and contact angle. Additionally, flexural strength tests, a dynamic mechanical analysis (DMA), and a thermogravimetric analysis (TGA) were conducted. The effect of natural fibres on the phase transition and degree of crystallinity was analysed using differential scanning calorimetry (DSC). The results showed that PLA degrades only under UV light, but not in the composter simulating the natural environment. However, the incorporation of both types of fibres accelerated degradation of PLA/fibres composites in soil. Flax fibre composites exhibited better mechanical properties than pure PLA. For composites with wool fibres, although they showed a significant acceleration of the degradation process in the soil, their large content in the composite caused a reduction of mechanical properties. This research showed the positive effect of the addition of natural fibres on the biodegradation of PLA.

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31

MacChesney, J. B., D. W. Johnson, D. A. Fleming e F. W. Walz. "Hybridised sol-gel process for optical fibres". Electronics Letters 23, n. 19 (1987): 1005. http://dx.doi.org/10.1049/el:19870705.

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32

Maurice, Terrence, e Jennifer Grealy. "Process for the production of protein fibres". Nutrition Research 5, n. 9 (settembre 1985): i. http://dx.doi.org/10.1016/s0271-5317(85)80129-9.

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33

Zhou, Bin, e Hui Ling Wang. "The Optimization of Regeneration Feather Protein /PVA Composite Fiber’s Production Technology Using Gray Clustering Analysis". Advanced Materials Research 332-334 (settembre 2011): 500–504. http://dx.doi.org/10.4028/www.scientific.net/amr.332-334.500.

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Abstract (sommario):

The spinning process of regeneration feather protein /PVA fiber is introduced in this article；The concentration and the solubility temperature of peracetic acid , ultrasonic processing time and the proportion of regeneration feather protein /PVA are selected as analysis objects, the fibers are extracted according to 9 orthogonal expts combinations, and the fiber’s performances are tested. Test schemes are optimized using gray clustering analysis which calculating process is showed with Matlab.

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34

Sirenko, H. O., M. B. Skladanyuk e L. M. Soltys. "Metallization of Carbon Fibers by Double and Triple Copper Composition". Фізика і хімія твердого тіла 16, n. 1 (15 marzo 2015): 185–92. http://dx.doi.org/10.15330/pcss.16.1.185-192.

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Abstract (sommario):

The theoretical foundations of physics and chemistry and application technology of single- and double-layer coating based on Cu0+Cu2O, Ni0+P, Pb0 on the surface of carbonated fibers have been reviewed. The changes of surface layers crystal structure of carbon fibres in the course of copper-plating have been investigated. The metallic coating process using modified formaldehyde and zinc technology was realized. It is established that copper content in copper – copper oxide increases when using two-layer alternately modified formaldehyde and zinc methods.

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35

Mongioví, Chiara, Maélys Jaillet, Dario Lacalamita, Nadia Morin-Crini, Michael Lecourt, Sandra Tapin-Lingua e Grégorio Crini. "A Strategy to Valorize a By-Product of Pine Wood (Pinus pinaster) for Copper Removal from Aqueous Solutions". Molecules 28, n. 18 (5 settembre 2023): 6436. http://dx.doi.org/10.3390/molecules28186436.

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Abstract (sommario):

This study describes the valorization of a pine wood by-product (Pinus pinaster) in the form of individualized fibers to a complex copper or more broadly metals present in an aqueous solution using a batch process. The adsorption results show that pine fibres activated by sodium carbonate are effective in recovering copper ions from monocontaminated or polycontaminated solutions of varying concentrations in a few minutes. One gram of material captures 2.5 mg of copper present in 100 mL of solution at pH 5 in less than 10 min. The results are perfectly reproducible and independent of pH between 3 and 5. The presence of the Na+ cation at concentrations of 0.1 M has no impact on material performance, unlike that of Ca2+ ions, which competes with Cu2+ ions for active sites. The adsorption process can be considered as rapid, as most of the copper is adsorbed within the first 10 min of exposure. Investigation of modeling possibilities shows some limitations. Indeed, the Weber and Morris and Elovich models show poor possibilities to describe all the kinetic data for copper adsorption on fibres. This may prove that the mechanism is far more complex than simple physisorption, chemisorption and/or diffusion. Complexation by wood fibers can be extended to solutions containing several types of metals. The results of this study show that the field of selective metal recovery could be a new way of valorizing by-products from the wood industry.

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36

Wan, Tao Yu, Mohammad Chowdhury e George K. Stylios. "The Formation and Morphology of PVA Ferrogel Nanofibre by the Electrospinning Process". Materials Science Forum 650 (maggio 2010): 361–66. http://dx.doi.org/10.4028/www.scientific.net/msf.650.361.

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Abstract (sommario):

Aqueous solutions of polyvinyl alcohol (PVA) with FeCl3 were homogenously mixed and subsequently electrospun; and its characteristics were studied as a function of voltage, tip-target distance and solution flow rate. Fiber mats of (PVA)/FeCl3 composite, in the diameter of 700–1100 nm were prepared by electrospinning. Lower concentrations of solution tended to facilitate the formation of fibres with beads. With increasing concentration, the morphology was improved with smooth and uniform fibres and the increased fibre diameters in the nano range. Spinning voltage also had an important influence on the diameters of the nano fibres, while the collection distance affected fibre diameters. Nano fibres of smaller diameter were formed when lower voltages are applied. The morphology of the electrospun from PVA/FeCl3 nano fibres and their magnetic power was observed and analyzed by scanning electron microscopy (SEM).The fibres produced in this way could potentially be applied to manufacture magnetic sensors, flexible magnets.

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37

Salzmann, Moritz, e Ralf Schledjewski. "Controlling Moisture Content of Natural Fibres in RTM-Process". Key Engineering Materials 809 (giugno 2019): 610–14. http://dx.doi.org/10.4028/www.scientific.net/kem.809.610.

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Abstract (sommario):

The quality of composite materials based on natural fibres is highly influence by humidity content of the fibres. For a high product quality in the resin-transfer-moulding (RTM) process a constant humidity content has to be achieved. As the humidity content of the fibres can change relative quickly depending on the humidity, measuring humidity content in the mould is beneficial. Near-Infrared-Spectroscopy (NIR) is a widely used tool for humidity content measurement allowing determination of the moisture content within seconds. To do so a calibration model with good accuracy is required. To generate the calibration model a dry flax woven fabric is placed in a climate chamber and weight change is recorded as well as NIR-Spectra. By correlating the spectra with the weight increase a model can be developed allowing to assign the spectra with unknown weight. This allows not only monitoring the moisture content of natural fibres with in the mould. Also can the moisture content reduced to an aspired value by applying vacuum to the preheated mould, before starting the resin infusion.

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38

Durante, M., e I. Crivelli Visconti. "Innovative Process for Manufacturing Laminates with Recycled Thermoplastic Reinforced by Natural Fibres". Advanced Composites Letters 17, n. 6 (novembre 2008): 096369350801700. http://dx.doi.org/10.1177/096369350801700601.

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Abstract (sommario):

For the processing of thermoplastics reinforced with natural fibres a new method based on the vacuum bag has been employed. Agave fibres reinforcing polyethylene (PE) laminates have been manufactured adopting low cost technology and recycled materials (matrix and fibres). In particular starting from recycled PE shoppers and low cost fibres, laminates have been manufactured by vacuum bag moulding at relatively low values of temperature. This technology consents to manufacture large panels adopting very simple moulds. In order to evaluate the manufacturing process, the properties of composite materials, carried out by static and dynamic mechanical analysis (DMA), have been compared with the single matrix (PE) properties.

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39

Chen, Lung-shun, Xiao-li Fan, Ke-mo Wang e Zong-lian Hou. "The Roles of Different Types of Afferent Fibres in the Process of Acupuncture Analgesia". American Journal of Chinese Medicine 13, n. 01n04 (gennaio 1985): 32. http://dx.doi.org/10.1142/s0192415x8500006x.

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Abstract (sommario):

In previous work, the reflex movement of the lower jaw was taken as an objective index of pain in awakening rabbits. It was found that analgesic action of various types of fibres were types I.II < types I.II.III < types I.II.III.IV, i.e. the effects were stronger with the involvement of those small-sized fibres. However, opinions differ as to whether small-sized fibres (includng Aδ wave and C wave) have analgesic effects. Therefore, the reaction of vascular movement which reflects the function of autonomic nerves was taken as an objective index of pain. 42 paralytic, awake rabbits with body weight of 2kg or so were used. In the peroneal nerve innervating "Zusanli'' point (from their distal to proximal ends) were placed the electrodes of electro-needling (limiting electro-needling) and Ag-AgCl, and those of recording and pain stimulation. The pain stimulations used were of single square-wave, of 2 times per second, of the pulse duration of 0.3 msec and of a continuance of 5 sec; their intensity being just enough to elicit the steady reaction of vascular movement. The electrodes of electric needling, electric pulses with a speed of 0.2 msec per second and the pulse duration of 0.2 msec were applied successively to stimulate those peroneal nerves. The roles played by various types of fibres in analgesic effects were further observed after different intensities, exciting the fibres of types I.II, tpes I.II.III and types I.II.III.IV respectively, and then through the Ag-AgCl electrode, D.C. anodal-blocking used to block the large-sized fibres and to excite type III or types III.IV of fibres respectively. Each experimental series was divided comparing, needling and after the withdrawal of the needle. Observations were made from three times in each step continually; the temperature was maintained at 16-28°C. The results have shown that the fibres of types I.II, types I.II.III and types I.II.III.IV were excited, respectively. It has turned out that their effective rates (including complete inhibition, apparent inhibition and slight inhibition) were 50% (types I.II), 78.6% (types I.II.III) and 92.8% (types I.II.III.IV); after the large-sized fibres had been blocked, the fibres of type IV and types III.IV were excited, with the effective rates of 90% (type IV) and 100% (types III.IV). Therefore, the analgesic effects of different types of fibres are I.II < III < IV, i.e. the smaller fibres the stronger the analgesic effects. The results are quite analogous to the previous work. This further proves the small-sized fibres have stronger analgesic effects upon pain response thatn large-sized fibres.

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40

Кондратович e L. Kondratovich. "The Basics for Comprehension of Adhesive Process Formation in Abdominal Cavity. Perioperative Prevention by means of Anti-Adhesive Drugs (Review of Literature)". Journal of New Medical Technologies 21, n. 3 (5 settembre 2014): 169–73. http://dx.doi.org/10.12737/5929.

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Abstract (sommario):

The review of literature presents a brief history of study of adhesive process from the beginning of XX century to the present, the modern concepts of the pathogenesis of adhesive process in the abdominal cavity after surgery on the organs of the small pelvis, taking into account the development of molecular biology, biochemistry, immunology. Problems of study of adhesive process are relevant at this stage of development of surgery of high reproductive technologies and the use of surgical energies, careful approach to the tissues. The processes that occur in the peritoneum after surgery are described in detail. The mechanism of neoangiogenesis in the newly formed growths is presented in detail, conditionally and schematically. The role of growth factors of cytokines, fibrinolysis in the process of formation of adhesions is reflected. The sequence of processes leading to the formation of adhesions is presented in the time interval: from the moment of peritoneal damage during operation up to 12 days of the postoperative period, the time of formation of fibrous adhesions. The structure of connective tissue fibres by components fibres, i.e. the structure of collagen fibers of different types is examined. The review presents conditional classification of anti-adhesive drugs with description of the properties and characteristics by the method of their application, the composition of constituent substances, the forms of release.

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41

Shalwan, A., M. Alajmi e A. Alajmi. "Effect of Aging Process in Different Solutions on Kenaf Fibre Structure and Its Interfacial Adhesion in Epoxy Composites". International Journal of Polymer Science 2018 (22 marzo 2018): 1–8. http://dx.doi.org/10.1155/2018/1290468.

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Abstract (sommario):

Interfacial adhesion of kenaf fibres in epoxy composites was investigated using single fibre pull-out test. Several aged kenaf fibres were tested in this work. Two types of kenaf fibres were used in the work, those treated with 6% NaOH and those untreated kenaf fibres. Kenaf fibres were aged in engine oil, water, salt water, and diesel. The pull-out tests were performed using microtensile tests. The tests were performed at 1 mm/min loading rate. Scanning electron microscopy was used to observe the damage on the fibres and the effect of the treatment. The general results revealed that aging of the fibres reduced their strength and interfacial adhesion. Salt water showed the least effect on the strength of the fibres. At most cases, the breakage in the fibres is the main failure. In other words, there is no remarkable effect of aging on the interfacial adhesion since the most impact was on the structure of the fibres.

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42

Coderch, Luisa, Ritamaria Di Lorenzo, Marika Mussone, Cristina Alonso e Meritxell Martí. "The Role of Lipids in the Process of Hair Ageing". Cosmetics 9, n. 6 (18 novembre 2022): 124. http://dx.doi.org/10.3390/cosmetics9060124.

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Abstract (sommario):

An obvious sign of ageing is the loss of hair colour due to a decrease or lack of melanin in hair fibres. An examination of the lipid levels and structure of grey hair determined using µ–FTIR revealed a high correlation between the characteristics of lipids located in the cuticle and the water dynamics of the fibres. Therefore, a deep study based on external and internal lipid extraction, an analysis using thin layer chromatography coupled to an automated flame ionisation detector, calorimetric analyses and the physico-chemical evaluation of the delipidated fibres were performed. Hairs were evaluated to identify changes in the organisation of these lipids using Fourier transform infrared spectroscopy and their effect on the water dynamics of the fibres. The primary differences observed for the lipid extracts from white hair compared to brown hair were the lower amount of the internal lipids extracted, which were primarily composed of free fatty acids (FFAs) and ceramides, with a higher content of lower phase transition peaks, indicating increased unsaturated compounds that promote higher fluidity of the lipid bilayers. The virgin white fibres exhibited lower levels of embedded water, with lower binding energies and higher water diffusion, indicating higher permeability. The IR study confirmed the low lipid levels and the greater disorder of white hair. These results may be of interest for cosmetic treatments to which patients with grey hair may be subjected.

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43

Khoshnava, Seyed Meysam, Raheleh Rostami, Mohammad Ismail e Alireza Valipour. "The Using Fungi Treatment as Green and Environmentally Process for Surface Modification of Natural Fibres". Applied Mechanics and Materials 554 (giugno 2014): 116–22. http://dx.doi.org/10.4028/www.scientific.net/amm.554.116.

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Abstract (sommario):

Although Natural Fibres have various potential and advantages such as lower in weight, embodied energy and toxicity but their drawbacks are provided relentless competition between natural and synthetics fibres. Intrinsically, Natural Fibres are hydrophilic that is leaded to poor resistance to moisture and incompatible to hydrophobic polymer matrix. This incompatibility of natural fibres results in poor fibre/matrix interface which in turn leads to reduce mechanical properties of the composites. This study try to litreature some methods of chemical treatment or surface modification of Natural Fibres for improving this drawback of natural fibres. The objective of this research is fungi treatment as Green Surface Treatment that is indicate to environmental friendlier process. The use of fungi can provide low cost, highly efficient and environmentally friendly alternatives to natural fibre surface treatment.

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44

Al Bakri, A. M. Mustafa, J. Liyana, M. N. Norazian, H. Kamarudin e C. M. Ruzaidi. "Mechanical Properties of Polymer Composites with Sugarcane Bagasse Filler". Advanced Materials Research 740 (agosto 2013): 739–44. http://dx.doi.org/10.4028/www.scientific.net/amr.740.739.

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Abstract (sommario):

Natural fibers reinforced polymer composites have gained more interest because of their biodegradable, light weight, less expensive sources, easy processing, high specific modulus and also environmentally friendly appeal. This paper presents an overview of a study aimed at showing on how the bio-composites which is bagasse fibers combined with resins as an alternative of bagasse-fiber-based composites panel. Transforming bagasse fibers into panel products provides a prospective solution. Bagasse-fiber-based composites offer potential as the core material replacing high density and expensive wood-based fiberboard. Biodegradable composites reinforced with bagasse fibres after being modified or treated by alkali treatment were prepared and also the mechanical properties were investigated. The bio-composites panel samples were processed by hot press machine. All panels were made with aspect ratios between bagasse fibers and polystyrene thermoplastics resins and also the sieve size of bagasse fibers which has short fibers and combination of short fiber and granules fibers. The polystyrene was added as a modified from natural fibers to determine the effect it had on physical and mechanical properties of the panel. Resin content level and panel density were very important in controlling the strength properties of the panels. Surface hardness value, compressive strength, bending strength and bending modulus values all increases in resin content level and panel density. Bagasse-based-panel products can be commercialize successfully if have good development of a cost manufacturing process on an establishment of a market base for the products.

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45

Monzon, Mario D., Rubén Paz, Fernando Ortega, Jose A. Chapela e Claudio Conde. "Process for reinforcing SLS parts by epoxy resin". Rapid Prototyping Journal 21, n. 3 (20 aprile 2015): 322–28. http://dx.doi.org/10.1108/rpj-08-2013-0079.

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Abstract (sommario):

Purpose – The purpose of this paper is to report on the use of a combination of selective laser sintering (SLS) and vacuum casting to create plastic composites made by additive manufacturing. Design/methodology/approach – The research has been carried out by approaching a new concept of the final part consistent in a plastic component, where the main body is made by SLS and the internal long fibres for reinforcing are made by vacuum casting of high-resistance epoxy resin. The part is designed for optimal number and distribution of the internal fibres taking into account the target relative stiffness (N/mm*kg). The methodology is applied to a pedal clutch of a car which has been tested in an equipment for fatigue and durability, being compared to the correspondent design for injection moulding. Findings – Research has proven that the approach introduces relevant improvement in mechanical properties of the base resin consistent in PA 3200GF (EOS), reinforced by internal long fibres of resin VG SP5. Experiments showed significant increase of stiffness in the pedal clutch made under this procedure, where the stiffness was 77 per cent higher than the conventional SLS part and only 11.7 per cent lower than the one made by injection moulding of PA 66 with 50 per cent fibreglass. Originality/value – The developed method introduces an alternative procedure for increasing the mechanical properties of plastic parts developed in SLS. Optimal orientation and distribution of long fibres clearly achieves better mechanical properties at low cost.

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46

Belyaeva, O. A., D. I. Krivtsov, A. V. Gaberling e V. Ya Varshavskii. "Oxidation process of polyacrylonitrile fibers". Fibre Chemistry 44, n. 5 (gennaio 2013): 268–72. http://dx.doi.org/10.1007/s10692-013-9444-x.

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47

Seo, Ikuo, Yasuo Sakaguchi e Ken Kashiwadate. "4863708 Process for producing carbon fibers and the carbon fibers produced by the process". Carbon 28, n. 2-3 (1990): II. http://dx.doi.org/10.1016/0008-6223(90)90028-w.

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48

Gajić, Ivana, Sanja Stojanović, Ivan Ristić, Snežana Ilić-Stojanović, Branka Pilić, Aleksandra Nešić, Stevo Najman et al. "Electrospun Poly(lactide) Fibers as Carriers for Controlled Release of Biochanin A". Pharmaceutics 14, n. 3 (27 febbraio 2022): 528. http://dx.doi.org/10.3390/pharmaceutics14030528.

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Abstract (sommario):

The aim of this study is to investigate the possibility of using electrospun polylactide (PLA) fibers as a carrier of the phytoestrogen biochanin A. Polylactide fibers were prepared with different contents of biochanin A by using an electrospinning method at specific process parameters. The obtained electrospun polylactide fibers, as carriers of biochanin A, were characterized by means of different methods. The presented results showed that the mechanical properties of PLA have not changed significantly in the presence of biochanin A. Scanning electron microscopy showed that the fine fiber structure is retained without visible deformations and biochanin A crystals on the surface of the fibres. The analysis by infrared spectroscopy showed that there are no strong interactions between polylactide and biochanin A molecules, which is a good prerequisite for the diffusion release of biochanin A from PLA fibers.The release of biochanin A from PLA fibers in buffer solution pH 7.4 at 37 °C was monitored by applying the HPLC method. The rate and time of the release of biochanin A from PLA fibers is in correlation with the amount of the active ingredient in the matrix of the carrier and follows zero-order kinetics. PLA fibers with biochanin A exhibit concentration-dependent activity on proliferation and migration of L929 fibroblasts in direct culture system in vitro, and proved to be suitable for a potential formulation for use in wound healing.

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49

Fouda, I. M., M. El Sherif e O. A. Bayoumi. "Effect of Dyeing Process on Optical Anisotropy of Polyester Fibres". Engineering Plastics 5, n. 4 (gennaio 1997): 147823919700500. http://dx.doi.org/10.1177/147823919700500405.

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Abstract (sommario):

A two beam interferometric technique using a pluta polarizing interference microscope has been used for the determination of the refractive index profiles and the birefringence of undyed and dyed polyester fibres with single and mixture colorants. Diameters and cross-sectional shapes of these fibres were determined from the diffraction pattern of a He-Ne laser beam, incident perpendicular to the fibre axis.

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50

Fouda, I. M., M. El Sherif e O. A. Bayoumi. "Effect of Dyeing Process on Optical Anisotropy of Polyester Fibres". Polymers and Polymer Composites 5, n. 4 (gennaio 1997): 281–89. http://dx.doi.org/10.1177/096739119700500405.

Testo completo

Abstract (sommario):

A two beam interferometric technique using a pluta polarizing interference microscope has been used for the determination of the refractive index profiles and the birefringence of undyed and dyed polyester fibres with single and mixture colorants. Diameters and cross-sectional shapes of these fibres were determined from the diffraction pattern of a He-Ne laser beam, incident perpendicular to the fibre axis.

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