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1
Borhan, Tumadhir Merawi. "Thermal and structural behaviour of basalt fibre reinforced glass concrete." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/thermal-and-structural-behaviour-of-basalt-fibre-reinforced-glass-concrete(2fcc3a9a-2012-4261-966b-4ff37420e032).html.
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This study aims to produce a type of concrete with both good thermal and mechanical properties by using environmentally friendly and low cost materials. In addition, the resistance of this concrete to fire conditions was investigated. The experimental work comprises two parts. In the first part, recycled glass was used as a partial replacement for natural sand (at proportions 20%, 40% and 60%) together with basalt fibre having different volume fractions (0.1%, 0.3%, and 0.5%). The results obtained from the experimental work showed that the optimum content is 20% glass and at 28 days, there was a 4.23% and 15% enhancement in the compressive strength and the splitting tensile strength respectively. Above 20% glass there was a slight reduction (6.6% and 22%) in the compressive strength and the splitting tensile strength when 60% glass was used. The results also showed that when glass sand and basalt fibre content increase, there is a decrease in the thermal conductivity range from 4.35% to 50% at temperature levels between 60oC to 600oC. The structural behaviour of this type of concrete was investigated in the second part of this study by carrying out small-scale slab tests at ambient and elevated temperatures. The results show that there is an increase in the load carrying capacity above the theoretical yield line load, due to membrane action, for all percentages of glass and volume fractions of basalt fibre ranging from 1.35 to 1.68 for the slab tested at ambient temperature and from 3.13 to 3.26 for the slabs tested at elevated temperature. Also the slabs with higher glass sand and basalt fibre content had a higher load enhancement and failed at a higher displacement compared to the control mix.A comparison between the simplified method and the finite element software package ABAQUS showed that the ABAQUS model gives reasonable predictions for the load-vertical displacement and the temperature-displacement relationships at both ambient and elevated temperature conditions, while the simplified method gives conservative predictions for the maximum allowable vertical displacement for the slab at elevated temperature. A parametric study showed that a 10 mm cover depth is the optimum depth as well as the reinforcement temperature predicted reduced with increasing load ratio (applied load/yield line load).
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Seghini, Maria Carolina. "Mechanical Analysis and Fibre/Matrix Interface Optimization for Next Generation of Basalt-Plant Fibre Hybrid Composites." Electronic Thesis or Diss., Chasseneuil-du-Poitou, Ecole nationale supérieure de mécanique et d'aérotechnique, 2020. http://www.theses.fr/2020ESMA0003.
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La prise de conscience mondiale des enjeux environnementaux a conduit à l’émergence de composites«verts», dans lesquels les fibres naturelles sont amenées à remplacer les fibres synthétiques. Ces nouveaux matériaux offrent des alternatives écologiques aux composites synthétiques traditionnels mais sont difficilement utilisables pour des applications semi-structurales ou structurales. Une solution possible à ce problème est le développement des composites hybrides, en combinant ensemble fibres naturelles et synthétiques. Dans ce cadre, l'objectif de cette étude était de développer des composites hybrides à base de fibres de basalte et de lin. Les composites hybrides ont été élaborés par moulage par infusion sous vide avec une matrice époxy. À des fins de comparaison,des composites 100% à fibres de lin et100%à fibres de basalte ont également été produits. Une caractérisation mécanique quasi-statique et dynamique amontré que l'hybridation permet d’obtenir un composite avec des propriétés mécaniques intermédiaires comparées à celles des composites à fibres de lin ou de basalte. Cependant, l’analyse approfondie des dommages a montré la nécessité d'optimiser la qualité d'adhésion de l'interface fibre/matrice afin d'accroître les performances mécaniques des composites hybrides obtenus. Pour cette raison, différents traitements de modification de surface ont été développés et étudiés pour les fibres de lin et de basalte. Un traitement physique par plasma (Plasma Enhanced Chemical Vapor Deposition) a été appliqué aux fibres de lin et de basalte. Les fibres de lin ont également été soumises à deux traitements chimiques utilisant des espèces enzymatiques et du CO2supercritique. Les effets des traitements sur la stabilité thermique, la morphologie et les propriétés mécaniques des fibres de lin et de basalte ont été étudiés. L’adhérence fibre/matrice a été analysée en réalisant des tests de fragmentation sur des composites monofilamentaires. La qualité de l'adhésion entre les fibres et les matrices époxy et vinylester a été évaluée en termes de longueur critique de fragment, de longueur de décohésion interfaciale et de résistance au cisaillement interfacial. La micto-tomographie haute résolution a été utilisée pour analyser les mécanismes d'endommagement lors des tests de fragmentation. Pour les deux types de fibres, les meilleurs résultat sont été obtenus grâce au traitement par plasma. Ce traitement a consisté à déposer un revêtement homogène de tétravinylsilane à la surface des fibres de basalte et de lin, ce qui a permis une augmentation significative de l’adhérence fibre/matrice, ouvrant ainsi la voie à la prochaine génération de composites hybrides plus respectueux de l’environnement et utilisables pour des applications semi-structuralesGlobal awareness of environmental issues has resulted in the emergence of “green” composites, in which natural fibres are used to replace synthetic ones. However, in semi-or structural applications, it can be inconvenient to use composites based on natural fibres. A possible solution to this problem is the development of hybrid composite materials, combining together plies of natural and synthetic fibres. In this framework, the aim of this research project was to develop basalt-flax fibre hybrid composites with a view to obtaining more environmentally friendly composites for semi-structural applications. Hybrid composites were produced through vacuum infusion molding with epoxy matrix.For comparison purposes, 100% flax fibre composites and 100% basalt fibre composites were also manufactured. A quasi-static and dynamic mechanical characterization showed that the hybridization allows the production of a composite with intermediate mechanical performances compared to those possessed by flax and basalt composites. However, the damage analysis has revealed the need to optimize the fibre/matrix interface adhesion quality, in order to increase the mechanical properties of the resulting hybrid composites. For this reason, different surface modification treatments have been specifically designed and investigated for flax and basalt fibres. Flax and basalt fibres were treated by the physical process of Plasma Enhanced Chemical Vapor Deposition. Flax fibres were also subjected to two chemical treatments using enzymatic species and supercritical CO2. The effects of the surface modification treatments on the thermal stability, morphology and mechanical properties of flax and basalt fibres have been investigated. The degree and extent of fibre/matrix adhesion were analyzed by micromechanical fragmentation tests on monofilament composites. The adhesion quality between fibres and both epoxy and vinylester matrices has been assessed in terms of critical fragment length, debonding length and interfacial shear strength. High-resolution μ-CT has been used to support the analysis of the damage mechanisms during fragmentation tests. For both flax and basalt fibres, the best results were obtained after the plasma polymer deposition process. This process was able to produce a homogeneous tetravinylsilane coating on the surface of basalt and flax fibres, which resulted in a significant increase in the fibre/matrix adhesion, thus paving the way for the next generation of more environmentally friendly hybrid composites for semi-structural applications
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Rengarajan, Muralidharan. "Laboratory testing of shotcrete with fibres of steel, basalt or synthetic materials." Thesis, KTH, Betongbyggnad, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-287310.
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Shotcrete or sprayed concrete has become an inevitable material for stabilising and supporting hard rock tunnels. To prevent rock block fallouts in the excavated tunnel, shotcrete is pneumatically projected under high pressure on the rock surface. This method has proven to reduce the construction time drastically, and the addition of fibres in the shotcrete material results in Fibre Reinforced Shotcrete (FRS). The fibres increased the strength of the parent matrix and made the reinforcement bar (mesh) placing procedure with its heavy labour work unnecessary. Even though FRS have been in use for many years, to design FRS lining there are currently no complete, widely used guidelines. Traditionally, the most frequently used testing was a traditional beam testing method which helps to determine the FRS mechanical properties. Previous studies prove that the result from beams often show a high scatter in the results. Another proposed standard testing method is the Round Determinate Panel method to determine the energy absorption capacity. This method has the potential to be a reliable test procedure with a repeatable and predictable crack pattern.In this project, an experimental investigation was carried out to understand the behaviour of macro fibres of steel, basalt and synthetic materials in FRS. The specimens were sprayed in situ and cast in laboratory, of which the in situ samples were assigned to different curing conditions. The test standard ASTM C-1550 was used to design the round panels and SS-EN 14488-3 for the beams. Each type of FRS specimen’s compressive strength was tested, evaluated and compared. The single fibre pullout strength was tested to determine the bond strength between shotcrete and fibres.The calculated results showed the coefficient of variation (COV) of energy absorption capacity from panels varied within 3 % – 13 % and the residual strength of beams within 12 % – 35 %. Irrespective of testing method, the Dramix 3D steel fibre and Minibars basalt fibre for the tested cases showed the lowest dispersion of result. Minibars showed a significant increase in compressive strength compared to the other fibres. Single fibre pullout testing concluded that the steel fibre had superior load capacity at the first crack. Minibars showed a strength close to that of steel fibres and a failure mode similar to that with synthetic fibres.
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Ammar, Mohamed Amine. "Bond durability of basalt fibre-reinforced polymers (BFRP) bars under freeze-and-thaw conditions." Thesis, Université Laval, 2014. http://www.theses.ulaval.ca/2014/30559/30559.pdf.
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Ce mémoire présente les résultats de l’étude de l’adhérence entre les barres en polymères renforcés de fibres de Basalte (PRFB) et le béton. Cinquante-quatre cylindres renforcés par des barres en PRFB et dix-huit cylindres renforcés par des barres en polymères renforcés de fibres de fibres de Verre (PRFV) ont été testés par le test d’arrachement. Les paramètres des tests incluent le type de la barre utilisée, le diamètre de la barre, la longueur d’ancrage et le nombre de cycles de gel-dégel (100 et 200 cycles). Les courbes adhérence-glissement des barres en PRFB et PRFV révèlent la même tendance. Les influences des différents paramètres sur l’adhérence ont été analysées. Les modèles analytiques BPE, BPE-modifié et CMR ont été calibrés pour décrire la relation adhérence-glissement des barres en PRFB. Les résultats montrent la capacité des barres en PRFB à remplacer les barres en PRFV dans le renforcement des structures.This thesis presents the test results of a study on the bond behavior of basalt fiber-reinforced polymers (BFRP) bars in concrete. Forty-five cylinders reinforced with BFRP bars and eighteen cylinders reinforced with glass fiber-reinforced polymer (GFRP) bars were tested in direct pullout conditions. Test parameters included the FRP material, the bar diameter, the bar’s embedment length in concrete and the number of freeze-and-thaw cycles (100 and 200 cycles). Bond-slip curves of BFRP and GFRP bars revealed similar trend. All BFRP specimens failed in a pullout mode at the bar-epoxy interface. The influence of various parameters on the overall bond performance of BFRP bars is analyzed. The BPE, modified-BPE, and CMR analytical models were calibrated to describe the bond-slip relationships of BFRP bars. Results demonstrate the promise of using BFRP bars as an alternative to GFRP bars in reinforcing concrete elements.
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Mahroug, Mohamed E. M. "Behaviour of continuous concrete slabs reinforced with FRP bars. Experimental and computational investigations on the use of basalt and carbon fibre reinforced polymer bars in continuous concrete slabs." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/6332.
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An investigation on the application of basalt fibre reinforced polymer (BFRP) and carbon fibre reinforced polymer (CFRP) bars as longitudinal reinforcement for simple and continuous concrete slabs is presented. Eight continuously and four simply concrete slabs were constructed and tested to failure. Two continuously supported steel reinforced concrete slabs were also tested for comparison purposes. The slabs were classified into two groups according to the type of FRP bars. All slabs tested were 500 mm in width and 150 mm in depth. The simply supported slabs had a span of 2000 mm, whereas the continuous slabs had two equal spans, each of 2000 mm. Different combinations of under and over FRP (BFRP/CFRP) reinforcement at the top and bottom layers of slabs were investigated. The continuously supported BFRP and CFRP reinforced concrete slabs exhibited larger deflections and wider cracks than the counterpart reinforced with steel. The experimental results showed that increasing the bottom mid-span FRP reinforcement of continuous slabs is more effective than the top over middle support FRP reinforcement in improving the load capacity and reducing mid-span deflections.
Design guidelines have been validated against experimental results of FRP reinforced concrete slabs tested. ISIS¿M03¿07 and CSA S806-06 equations reasonably predicted the deflections of the slabs tested. However, ACI 440¿1R-06 underestimated the deflections, overestimated the moment capacities at mid-span and over support sections, and reasonably predicted the load capacity of the continuous slabs tested.
On the analytical side, a numerical technique consisting of sectional and longitudinal analyses has been developed to predict the moment¿curvature relationship, moment capacity and load-deflection of FRP reinforced concrete members. The numerical technique has been validated against the experimental test results obtained from the current research and those reported in the literature. A parametric study using the numerical technique developed has also been conducted to examine the influence of FRP reinforcement ratio, concrete compressive strength and type of reinforcement on the performance of continuous FRP reinforced concrete slabs. Increasing the concrete compressive strength decreased the curvature of the reinforced section with FRP bars. Moreover, in the simple and continuous FRP reinforced concrete slabs, increasing the FRP reinforcement at the bottom layer fairly reduced and controlled deflections.
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Mahroug, Mohamed Elarbi Moh. "Behaviour of continuous concrete slabs reinforced with FRP bars : experimental and computational investigations on the use of basalt and carbon fibre reinforced polymer bars in continuous concrete slabs." Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/6332.
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An investigation on the application of basalt fibre reinforced polymer (BFRP) and carbon fibre reinforced polymer (CFRP) bars as longitudinal reinforcement for simple and continuous concrete slabs is presented. Eight continuously and four simply concrete slabs were constructed and tested to failure. Two continuously supported steel reinforced concrete slabs were also tested for comparison purposes. The slabs were classified into two groups according to the type of FRP bars. All slabs tested were 500 mm in width and 150 mm in depth. The simply supported slabs had a span of 2000 mm, whereas the continuous slabs had two equal spans, each of 2000 mm. Different combinations of under and over FRP (BFRP/CFRP) reinforcement at the top and bottom layers of slabs were investigated. The continuously supported BFRP and CFRP reinforced concrete slabs exhibited larger deflections and wider cracks than the counterpart reinforced with steel. The experimental results showed that increasing the bottom mid-span FRP reinforcement of continuous slabs is more effective than the top over middle support FRP reinforcement in improving the load capacity and reducing mid-span deflections. Design guidelines have been validated against experimental results of FRP reinforced concrete slabs tested. ISIS-M03-07 and CSA S806-06 equations reasonably predicted the deflections of the slabs tested. However, ACI 440-1R-06 underestimated the deflections, overestimated the moment capacities at mid-span and over support sections, and reasonably predicted the load capacity of the continuous slabs tested. On the analytical side, a numerical technique consisting of sectional and longitudinal analyses has been developed to predict the moment-curvature relationship, moment capacity and load-deflection of FRP reinforced concrete members. The numerical technique has been validated against the experimental test results obtained from the current research and those reported in the literature. A parametric study using the numerical technique developed has also been conducted to examine the influence of FRP reinforcement ratio, concrete compressive strength and type of reinforcement on the performance of continuous FRP reinforced concrete slabs. Increasing the concrete compressive strength decreased the curvature of the reinforced section with FRP bars. Moreover, in the simple and continuous FRP reinforced concrete slabs, increasing the FRP reinforcement at the bottom layer fairly reduced and controlled deflections.
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Scheffler, Christina, Theresa Förster, and Edith Mäder. "Beschleunigte Alterung von Glasfasern in alkalischen Lösungen: Einflüsse auf die mechanischen Eigenschaften." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2009. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1244042771688-80994.
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In alkalischen Lösungen führt die Reaktion von Hydroxylionen mit den Si-O-Si-Bindungen des Glasnetzwerks zur Bildung hydratisierter Oberflächen und gelöstem Silikat. Der Grad der Korrosion bzw. der Alterung der Glasfaser ist abhängig von der chemischen Zusammensetzung des Glases und Korrosionslösung sowie von Zeit und Temperatur. Die Untersuchung von Glasfasern verschiedener chemischer Zusammensetzung in NaOH- sowie Zementlösungen zeigte, dass die inhibierende Wirkung von Ca-Ionen zu einem veränderten Korrosionsmechanismus führt. Dies konnte anhand der mechanischen Eigenschaften der Glasfasern sowie rasterelektronenmikroskopischen Untersuchungen gezeigt werden. Während die Korrosion in NaOH-Lösung zu einer ausgeprägten Umwandlung der gesamten äußeren Glasfaserschicht in Reaktionsprodukte führte, zeigten Glasfasern in Zementlösung bei gleichem pH-Wert einen stark lokal begrenzten, punktförmigen Angriff. Daraus resultieren unterschiedliche mechanische Eigenschaften der Glasfasern in Abhängigkeit von der gewählten Korrosionslösung.
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Hamed, Sarah. "Shear Contribution of Basalt Fiber-Reinforced Concrete Reinforced with Basalt Fiber-Reinforced Polymer Bars." Master's thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/34008.
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Cette étude évalue expérimentalement et analytiquement le comportement au cisaillement des poutres en béton renforcé de fibres de basalte (BRFB) renforcées longitudinalement avec des barres en polymère renforcé de fibres de basalte (PRFB). Un nouveau type de macro-fibres de basalte a été ajouté au mélange de béton pour produire le mélange de BRFB. Quatorze poutres (152 x 254 x 2000 mm) sans armature transversale ajouté ont été testées sous une configuration de chargement à quatre points jusqu'à la défaillance. Les poutres ont été regroupés en deux groupes A et B en fonction de leurs rapports portée de cisaillement/profondeur, a/d. Les poutres du groupe A avaient un rapport a/d de 3,3 tandis que celles du groupe B avaient un rapport a/d de 2,5. Outre les rapports a/d, les paramètres étudiés comprenaient la fraction volumique des fibres ajoutées (0,75 et 1,5%) et le taux de renforcement longitudinal des barres en PRFB (0,31, 0,48, 0,69, 1,05 et 1,52). Les résultats des tests ont montré que l’ajout de macro-fibres de basalte au mélange de béton améliorait sa résistance à la compression. Une relation directe entre la fraction volumique de fibres, Vf, et la résistance à la compression a été observée. Les cylindres de béton coulés avec une Vf de 0,75 et 1,5% ont entraîné une augmentation de 11 et 30% de leur résistance à la compression par rapport à ceux moulés en béton standard (sans fibres), respectivement. L'ajout de fibres a également amélioré le mode de défaillance des poutres BRFB-PRFB que les poutres de contrôle coulées avec du béton standard. L’augmentation de la fraction volumique des fibres a réduit l’espacement entre les fissures et gêné sa propagation. Une amélioration significative des capacités de cisaillement des poutres testées a également été observée lorsque les macro-fibres de basalte ont été ajoutées à une fraction volumique Vf de 0,75. L'augmentation moyenne des capacités de cisaillement des poutres des groupes A et B, ayant les mêmes taux de renforcement, était respectivement de 45 et 44%, par rapport à celles des poutres de contrôle. Il a été noté que le gain en capacité de cisaillement des poutres testées était plus prononcé dans les poutres avec a/d= 3,3 que dans les poutres avec a/d = 2,5 lorsque le taux de renforcement augmentait. Au cours de la phase analytique, plusieurs modèles ont été utilisés pour prédire les capacités de cisaillement des poutres. Tous les modèles disponibles surestimaient les capacités de cisaillement des poutres testées avec un rapport moyen Vpre/Vexp compris entre 1,29 et 2,64. Cette observation a montré que ces modèles ne permettaient pas de prédire les capacités de cisaillement des poutres BRFB-PRFB. Un nouveau modèle modifié intégrant le type de renforcement longitudinal, le type de béton fibré et la densité du béton est proposé. Le modèle d’Ashour et al. -A (1992) a été modifié en utilisant un facteur égal au rapport entre le module des barres en PRF, Ef, et celui des barres en acier Es. Ce rapport prend en compte la différence de propriétés entre les barres en PRF et celles en acier, négligée par les modèles précédents. Le modèle proposé prédit bien les capacités de cisaillement des poutres BRFB-PRFB testées dans la présente étude avec des rapports moyens Vpre/Vexp = 0,82 ± 0,12 et 0,80 ± 0,01 pour les poutres des groupes A et B, respectivement. Les capacités de cisaillement des poutres en béton léger testées par Abbadi (2018) ont été prédites avec un rapport moyen Vpre/Vexp = 0,77 ± 0,05. De plus, le modèle prédit bien les capacités de cisaillement des poutres coulées avec du béton qui contient des fibres en acier testées par Awadallah et al. (2014) avec un rapport moyen Vpre/Vexp = 0,89 ± 0,07. Cela indique la large gamme d'applicabilité du modèle proposé. Cependant, il est recommandé d’évaluer le modèle proposé sur un ensemble de données plus large que celui présenté dans cette étude.This study evaluates both experimentally and analytically the shear behavior of basalt fiber-reinforced concrete (BFRC) beams reinforced longitudinally with basalt fiber-reinforced polymer (BFRP) bars. A new type of basalt macro-fibers was added to the concrete mix to produce the BFRC mix. Fourteen beams (152 x 254 x 2000 mm) with no transverse reinforcement provided were tested under four-point loading configuration until failure occurred. The beams were grouped in two groups A and B depending on their span-to-depth ratios, a/d. Beams of group A had a ratio a/d of 3.3 while those of group B had a ratio a/d of 2.5. Besides the span-to-depth ratios, the parameters investigated included the volume fraction of the fibers added (0.75 and 1.5%) and the longitudinal reinforcement ratio of the BFRP reinforcing bars (0.31, 0.48, 0.69, 1.05, and 1.52). The test results showed that the addition of basalt macro-fibers to the concrete mix enhanced its compressive strength. A direct relationship between the fiber volume fraction, Vf, and the compressive strength was observed. Concrete cylinders cast with Vf of 0.75 and 1.5% yielded 11 and 30% increase in their compressive strengths over those cast with plain concrete, respectively. The addition of fibers greatly enhanced the shear capacity of BFRC-BFRP beams compared to their control beams cast with plain concrete. The increase of the fiber volume fraction decreased the spacing between cracks and hindered its propagation. A significant enhancement in the shear capacities of the tested beams was also observed when the basalt macro-fibers were added at a volume fraction Vf of 0.75%. The average increase in the shear capacities of beams of group A and B, having the same reinforcement ratios, were 45 and 44%, respectively, in comparison with those of the control beams. It was noticed that the gain in shear capacities of the tested beams was more pronounced in beams with a/d = 3.3 than in beams with a/d = 2.5 when the reinforcement ratio increased. In the analytical phase, several models were used to predict the shear capacities of the beams. All of the available models overestimated the shear capacities of the tested beams with average ratio Vpre/Vexp ranging between 1.29 to 2.64. This finding indicated that these models were not suitable to predict the shear capacities of the BFRC-BFRP beams. A new modified model incorporating the type of the longitudinal reinforcement, the type of FRC used, and the density of concrete is proposed. The model of Ashour et al. –A (1992) was calibrated using a calibration factor equal to the ratio of modulus of FRP bars used, Ef, and that of steel bars, Es. This ratio takes into consideration the difference in properties between the FRP and steel bars, which was overlooked by previous models. The proposed model predicted well the shear capacities of the BFRC-BFRP beams tested in the current study with average ratios Vpre/Vexp = 0.82 ± 0.12 and 0.80 ± 0.01 for beams of groups A and B, respectively. The shear capacities of the lightweight concrete beams tested by Abbadi (2018) were predicted with an average ratio Vpre/Vexp = 0.77 ± 0.05. Moreover, the model predicted well the shear capacities of the SFRC beams reinforced with BFRP bars tested by Awadallah et al. (2014) with an average ratio Vpre/Vexp = 0.89 ± 0.07. This indicates the wide range of applicability of the proposed model. However, it is recommended that the proposed model be assessed on larger set of data than that presented in this study
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Gaumond, Baptiste. "Compréhension des interfaces / interphases formées dans les composites PPS / fibres de carbone et PPS / fibres de basalte réalisés à partir de mèches comélées et retordues." Thesis, Lyon, 2020. http://www.theses.fr/2020LYSEI064.
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Ces travaux de thèse sont consacrés à la compréhension des relations structures-propriétés des matériaux composites réalisés à partir de mèches hybrides composées de la matrice thermoplastique, le polysulfure de phénylène et de renforts qui peuvent être soit du carbone soit du basalte. Plusieurs axes de recherche ont été approfondis dans ces travaux : i) l’impact des procédés de fabrication des mèches sur les propriétés finales des composites, ii) la compréhension des interactions fibres-matrice dans les systèmes étudiés et iii) l’optimisation de ces interactions à l’interphase. Ces travaux ont démontré le lien établi entre les propriétés mécaniques et structurelles des mèches hybrides et les propriétés finales des matériaux composites obtenus. Le procédé de comélage par air conditionne en partie les propriétés finales des composites en diminuant les propriétés mécaniques des fibres de renfort. Cette dégradation n’est pas observée pour le procédé de retordage. Dans le même temps, les composites obtenus par comélage sont de meilleure qualité en termes d’homogénéité, propriétés mécaniques et taux de porosité par rapport à ceux issus du procédé de retordage. Dans un second temps, l’adhérence de l’ensemble des systèmes étudiés a été évaluée à l’échelle micromécanique et corrélée à l’échelle macroscopique. Des essais de vieillissement accélérés ont également été conduits pour discriminer les solutions les plus durables. Une dernière partie de ces travaux est consacrée à l’optimisation des propriétés interfaciales des systèmes étudiés. Les deux voies explorées ont donné des résultats intéressants : l’utilisation d’un mélange polymère PPS / PE-EMA-GMA a permis d’améliorer jusqu’à 56 % l’IFSS avec les fibres de basalte et l’utilisation d’un sel imidazolium en tant qu’agent interfacial dans la matrice a permis d’améliorer de 25 % l’IFSS obtenu avec les fibres de carboneThis thesis work is devoted to the understanding of the structure-properties relationships of composite materials made from hybrid rovings composed of the thermoplastic matrix, polyphenylene sulphide, and reinforcements that can be either carbon or basalt. Thus, several lines of research have been pursued in this work: i) the impact of the commingling process on the final properties of composites, ii) the understanding of fiber-matrix interactions and iii) the optimization of those interactions in the interface. This work first demonstrated the link established between the mechanical and structural properties of the hybrid yarns and the mechanical properties of composite materials. The air commingling process degrades the resistance of the fibers and this is observed both on filaments tensile tests and commingled yarns. This degradation is not observed on twisted yarns. In the same time, composites based on commingled yarns show a better homogeneity, mechanical properties and a lower porosity rate. In a second step, the adhesion developped in all composite systems was evaluated at the micromechanical scale and correlated at the macroscopic scale. Accelerated ageing tests were also carried out to discriminate the most durable solutions. A final part of this work is devoted to the optimization of the interfacial properties of the systems studied. Two solutions were developed and gave interesting results: the use of a PPS / PE-EMA-GMA polymer mixture allowed to improve up to 56% the IFSS with basalt fibers and the use of an imidazolium salt as interfacial agent in the matrix allowed to improve by 25% the IFSS obtained with carbon fibers
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Zourek, Milan. "Možnosti aplikace čedičových vláken do betonu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2018. http://www.nusl.cz/ntk/nusl-372072.
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This diploma thesis deals with possibilities of application of basalt fibers in concrete and in cementitious composites. In the theoretical part there is a summary of fibers usually used for fiberconcretes. Manufacturing process of basalt fibers is described, and properties of basalt fibers are summarized. Next part deals with properties of basalt fiber reinforced concrete. Concretely fresh properties, physical-mechanical properties, shrinkage and cracking, microstructure and fire resistance. The last chapter deals with fire resistance of concrete in general. The experimental part of this diploma thesis is divided into two phases. There were two mixes of basalt fiber reinforced concrete made with basalt aggregate and one mix of concrete without basalt fibers in the first phase. Density, consistency by slump and air content were determined as fresh properties. As hardened properties density, compressive strength and flexural strength were determined. There was determined the effect of the temperatures 600 and 800 °C on density, compressive strength and outward of specimens. Also, deformation during the high temperature curing was recorded. In the second phase of the experimental part there were three mixes of cementitious composite made with basalt fibers and one cementitious composite without basalt fibers. Density was determined as a fresh property. Material was monitored during its mixing. As a hardened properties density, flexural strength and compressive strength were determined. There was determined the effect of the temperatures 600 and 800 °C on density, flexural strength, compressive strength and outward of specimens.
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Palme, Jahi. "Investigation of the Addition of Basalt Fibres into Cement." TopSCHOLAR®, 2014. http://digitalcommons.wku.edu/theses/1361.
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Mechanical properties of concrete are most commonly determined using destructive tests including: compression, flexure, and fracture notch specimen tests. However, nondestructive tests exist for evaluating the properties of concrete such as ultrasonic pulse velocity and impact echo tests. One of major issues with concrete (which has cement as its prime ingredient) is that unlike steel it is quasi-brittle material. It tends to want to crack when tensile stresses develop. Fibres have been added to concrete for many years to reduce the amount of and size of cracks cause by temperature changes or shrinkage. In more recent years, significant research has been carried out into the effect of the addition of basalt fibres to cement has on its mechanical strength. As well, developing concrete that is more durable, flexible, stronger, and less permeable than traditional concrete has been explored. It has become important to test and verify improvements that are made to the cement by basalt fibres as well as testing the general strength of concrete to stand up to constant pressure at varied strengths.
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Abbas, Usama. "Materials Development of Steel-and Basalt Fiber-Reinforced Concretes." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for konstruksjonsteknikk, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-24224.
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Concrete is a structural composite material with excellent properties when subjected to compression. But the poor ability to resist tensile stresses forces the concrete to be used with reinforcement. Commonly, large continuous steel bars have been applied as reinforcement since mid-1800’s to carry the tensile loads. Placing the steel bars takes many man-hours, which contributes to a significant part of the total concrete costs. By eliminating the reinforcement part of the construction work, the costs can be reduced considerably. Fibers have been incorporated into building materials since ancient times to improve the properties. Today, fibers are incorporated in concretes to improve certain properties of this material. They are added to enhance the ductility of the concretes. Additionally, the tensile and the flexural strengths of the material are enhanced. The crack widths and their propagation are decreased by the insertion of fibers. Research over the years have shown that fiber reinforcement has sufficient strength and ductility to be used as a complete replacement to conventional steel bars in some types of structures; foundations, walls, slabs. Fibers are also used in beams in combination with conventional reinforcement which increase the capacity and the stiffness of the concrete. The technology that is available today has made is possible to consider fiber reinforcement without the use of conventional steel bars in load carrying structures. For this to be a reality, the fibers must be distributed and oriented as expected, which is difficult. If fibers can be used without the need of steel reinforcement bars, the reinforcement part of the construction work will be eliminated. Hence, the construction costs will be significantly reduced.In recent years, a project within COIN has set the aim to develop a high tensile strength all-round concrete which exhibits a residual flexural tensile strength in the range of 10-15 MPa and that can be applied in load carrying structures. This MSc-thesis is a part of this work and it has consisted of testing fiber-reinforced self-compacting concretes with different types and contents of fibers, namely steel fibers and basalt fibers. The different concrete mixes were tested and the corresponding fresh and hardened concrete properties were evaluated and compared.Based upon the results achieved in these experiments, the conclusion was taken of whether or not the different concrete mixes could be used for the purpose the COIN project was aiming for.
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Liu, Jianwen. "Untersuchung von Verbundwerkstoffen mit Basalt- und PBO-Faser-Verstärkung." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1205926921343-19844.
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Zur Erweiterung der Grundlagenkenntnisse für diese beiden bisher wenig genutzten Verstärkungsfasern werden in dieser Arbeit Einzelfaserzugversuche durchgeführt, um den Einfluss der Prüfbedingungen und der Faseroberflächenbehandlungen auf die mechanischen Eigenschaften der Fasern zu charakterisieren. Durch die Analysen der unimodalen und bimodalen Weibullverteilung wird der Zusammenhang zwischen der Faserzugfestigkeit und den kritischen Oberflächendefekten untersucht. Um den Einfluss der Faseroberflächenbehandlungen auf die Oberflächenenergien und Grenzflächenhaftung zu ermitteln, werden in dieser Arbeit der Schlichteauftrag aus wässriger Phase (Silan, Filmbildner), Plasmabehandlungen in verschiedenen Medien, Excimer-UV-Bestrahlungen in Anwesenheit verschiedener Monomeren und eine Säurebehandlung durchgeführt. Zur Charakterisierung der Oberflächentopografie der oberflächenbehandelten Fasern vor und nach dem Einzelfaserauszugversuch wird die Rasterkraftmikroskopie (AFM) verwendet. Der Effekt einer Plasmabehandlung auf die freie Oberflächenenergie der PBO-Fasern und die Grenzflächenscherfestigkeit wird mittels der Kontaktwinkelmessung und der Einzelfaserauszugprüfung untersucht. Um die durch diese Oberflächenmodifizierungen hervorgerufenen Veränderungen der mechanischen Verbundeigenschaften sowie der Faser-Matrix-Haftung zu charakterisieren, werden in dieser Arbeit sowohl endlosfaserverstärkte thermoplastische und duroplastische Unidirektionalverbunde bzw. kurzfaserverstärkte thermoplastische Verbunde als Modellfälle betrachtet, bei denen sowohl die Verstärkungsfasern als auch die Matrix signifikant unterschiedlich sind. Zur Verstärkung werden zwei ausgewählte Fasermaterialien (Basalt- und PBO-Fasern) und als Matrix zwei Thermoplaste (PP und PA6) sowie ein Epoxidharz ausgewählt. Der Einsatz von Commingling-Hybridfäden zur Entwicklung der thermoplastischen Unidirektionalverbunde erfordert Voruntersuchungen zur Lufttexturierung mit verschiedenen Düsen und Auswahl der günstigsten Prozessparameter.
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Lapena, Mauro Henrique. "Estudo do comportamento mecânico de cilindros de compósito epóxi/fibra de basalto em ensaios hidrostáticos." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/85/85134/tde-23032017-152933/.
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O objetivo deste trabalho foi estudar o comportamento mecânico de cilindros de compósito polimérico reforçado com fibras. Para isso, foram produzidos cilindros com extremidades abertas reforçados com fibra de basalto e fibra de vidro, utilizando a técnica de enrolamento filamentar (filament winding). Estes cilindros foram submetidos a ensaio hidrostático com carregamento circunferencial, ensaio de ruptura de anel (split disk test) e ensaio de resistência ao cisalhamento interlaminar (ILSS). Uma placa do compósito de fibra de basalto foi produzida por enrolamento filamentar, para caracterização por ensaio de resistência à tração. Todos cilindros submetidos ao ensaio hidrostático apresentaram fratura localizada em uma faixa de altura do cilindro, com extensas delaminações das camadas circunferenciais. Os compósitos epóxi/fibra de basalto superaram ou igualaram os de compósito epóxi/fibra de vidro nas comparações entre resultados dos valores das propriedades mecânicas avaliadas, nas porcentagens: resistência à tração aparente de ruptura de anel em 45% e 43% em resistência específica; ILSS, em 11%; resistência/tensão de membrana de ruptura no ensaio hidrostático, em 55%.The aim of this work was to study the mechanical behavior of fiber reinforced polymer composite cylinders. For this purpose, cylinders reinforced with basalt and glass fibers were produced, with open-ended geometry, using filament winding technique. These cylinders were submitted to hydrostatic test under circunferential loading, split disk (ring segment) test and interlaminar shear strength (ILSS). A basalt fiber composite plate was produced by filament winding for characterization by tensile strength test. All cylinders submitted to hydrostatic test presented fracture located in the height range of the cylinder, with extensive delamination of the circumferential layers. The epoxy/basalt fiber composites overcame or equated the epoxy/glass fiber composites in comparisons between results of the mechanical properties, tensile strength in split disk, in 45% and 43% in specific strength; ILSS in 11%; membrane tensile strength in the hydrostatic test, in 55%.
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Liu, Jianwen. "Untersuchung von Verbundwerkstoffen mit Basalt- und PBO-Faser-Verstärkung." Doctoral thesis, Technische Universität Dresden, 2007. https://tud.qucosa.de/id/qucosa%3A24101.
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Zur Erweiterung der Grundlagenkenntnisse für diese beiden bisher wenig genutzten Verstärkungsfasern werden in dieser Arbeit Einzelfaserzugversuche durchgeführt, um den Einfluss der Prüfbedingungen und der Faseroberflächenbehandlungen auf die mechanischen Eigenschaften der Fasern zu charakterisieren. Durch die Analysen der unimodalen und bimodalen Weibullverteilung wird der Zusammenhang zwischen der Faserzugfestigkeit und den kritischen Oberflächendefekten untersucht. Um den Einfluss der Faseroberflächenbehandlungen auf die Oberflächenenergien und Grenzflächenhaftung zu ermitteln, werden in dieser Arbeit der Schlichteauftrag aus wässriger Phase (Silan, Filmbildner), Plasmabehandlungen in verschiedenen Medien, Excimer-UV-Bestrahlungen in Anwesenheit verschiedener Monomeren und eine Säurebehandlung durchgeführt. Zur Charakterisierung der Oberflächentopografie der oberflächenbehandelten Fasern vor und nach dem Einzelfaserauszugversuch wird die Rasterkraftmikroskopie (AFM) verwendet. Der Effekt einer Plasmabehandlung auf die freie Oberflächenenergie der PBO-Fasern und die Grenzflächenscherfestigkeit wird mittels der Kontaktwinkelmessung und der Einzelfaserauszugprüfung untersucht. Um die durch diese Oberflächenmodifizierungen hervorgerufenen Veränderungen der mechanischen Verbundeigenschaften sowie der Faser-Matrix-Haftung zu charakterisieren, werden in dieser Arbeit sowohl endlosfaserverstärkte thermoplastische und duroplastische Unidirektionalverbunde bzw. kurzfaserverstärkte thermoplastische Verbunde als Modellfälle betrachtet, bei denen sowohl die Verstärkungsfasern als auch die Matrix signifikant unterschiedlich sind. Zur Verstärkung werden zwei ausgewählte Fasermaterialien (Basalt- und PBO-Fasern) und als Matrix zwei Thermoplaste (PP und PA6) sowie ein Epoxidharz ausgewählt. Der Einsatz von Commingling-Hybridfäden zur Entwicklung der thermoplastischen Unidirektionalverbunde erfordert Voruntersuchungen zur Lufttexturierung mit verschiedenen Düsen und Auswahl der günstigsten Prozessparameter.
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Quispe, C., D. Lino, J. Rodríguez, and A. Hinostroza. "Concrete cracking control in underwater marine structures using basalt fiber." IOP Publishing Ltd, 2021. http://hdl.handle.net/10757/655950.
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The construction of coastal ports requires the use of materials that meet the demands of the marine environment, to prevent underwater concrete structures from cracking and spalling easily; basalt fiber is used to delay the expansion of concrete and prevent the formation of cracks. This research studies the behavior of concrete for prefabricated piles with Portland Cement Type I and basalt fibers added in 0.1%, 0.3% and 0.6%; the results indicate that the fiber is suitable for concrete, the slump decreases, the compressive strength increases for specimens cured in tap water and sea water, the relationship between resistances does not vary, and the depth of carbonation decreases.
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Iuliano, Marco. "Studio e caratterizzazione di sensori distribuiti in fibra ottica basati su scattering Brillouin." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13443/.
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Nel presente elaborato si mostra lo studio e la caratterizzazione di sensori distribuiti in fibra ottica (DOFS) basati sulla tecnica Brillouin Optical Time-Domain Analysis.
Si presenta una particolare implementazione ai sistemi BOTDA basati sulla modifica del BFRL (Brillouin Fiber Ring Laser) al fine di ottimizzarne la convenzionale configurazione per renderli economicamente vantaggiosi, permettendone un ampio
impiego e sviluppo su larga scala.
La sorgente BFRL presentata mostra degli adeguati valori di potenza del segnale di probe in uscita, un largo intervallo di modulazione ed una linewidth.
Essa permette quindi di ottenere un ottimo valore di risoluzione spaziale di 5 m per una fibra SMF della lunghezza di ~2.6 km, cui corrispondono i relativi valori di risoluzione di temperatura e strain rispettivamente di ~0.5°C e ~10 με.
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Lewis, Jeremy D. "The Effects of Corrosion on Reinforced Concrete with Fiber Addition." University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1355171708.
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Abbadi, Abdulrahman. "Shear contribution of fiber-reinforced lightweight concrete (FRLWC) reinforced with basalt fiber reinforced Polymer (BFRP) bars." Master's thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/31848.
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Cette étude porte sur le comportement au cisaillement des poutres en béton léger fibré et renforcées par des barres de polymère renforcé de fibres de basalte (PRFB). Dix poutres (150x250x2400 mm) coulées avec du béton fibré ou non-fibré ont été testées en flexion. Deux poutres ont été coulées sans fibres (poutres contrôles) tandis que les huit autres poutres ont été coulées avec du béton contenant des différents types et pourcentages de fibres. Les paramètres étudiés comprenaient le type de fibres ajoutés au béton (fibres de basalte, de polypropylène et d’acier), la fraction volumique des fibres (0, 0,5 et 1,0%) et les taux de renforcement des barres de PRFB (0,95 et 1,37%). Une comparaison entre les résultats expérimentaux et les modèles analytiques actuellement disponibles dans la littérature a été réalisée pour évaluer l'applicabilité de tels modèles pour prévoir la capacité des poutres testées en cisaillement. Les résultats de la présente étude indiquent que la géométrie des fibres joue un rôle important dans l'augmentation du nombre de fissures que celles observées dans les poutres contrôles. L'ajout de fibres a entraîné une défaillance plus ductile et le taux d'ouverture des fissures était retardé. La largeur de la fissure a diminué avec l'augmentation des ratios de renforcement longitudinal et des fractions volumiques des fibres. L'augmentation du taux de renforcement longitudinal a entraîné une rigidité plus élevée et a diminué les flèches à tous les stades du chargement. Les poutres coulées avec 1% de fibres de basalte, de polypropylène et d'acier ont montré une augmentation dans leurs capacités de cisaillement par rapport aux poutres contrôles d'environ 11, 16 et 63%, respectivement. Le type de fibres affectait de manière significative le gain dans les capacités de cisaillement des poutres, ce qui était attribué aux différentes propriétés physiques et mécaniques des fibres utilisées, telles que leurs dimensions, leurs géométries, et leurs mécanismes de liaison avec le béton. Les poutres coulées avec des fibres en acier à 0,5% présentaient des capacités de cisaillement plus élevées que celles coulées avec des fibres de basalte et de polypropylène de 23 et 16% respectivement, alors que les poutres coulées avec des fibres en acier à 1% de volume présentaient un gain de 47 et 41%, respectivement, dans leurs capacités. Les capacités de cisaillement prévues selon les équations de la norme CSA-S806-12 étaient conservatrices avec un rapport moyen Vprév/Vexp de 0,80 (écart type, ÉT = 0,12) pour les poutres sans fibres. Les modèles établis par Shin (1994) et Gopinath (2016) ont fourni de bonnes prévisions quant aux capacités de cisaillement des poutres en béton renforcé de fibres de basalte avec des ratios moyens Vprév/Vexp de 1,34 (ÉT = 0,09) et de 1,35 (ÉT = 0,07), respectivement. De même, le modèle de Shin (1994) a bien prédit les capacités de cisaillement des poutres en béton armé de fibres de polypropylène avec un rapport Vprév/Vexp de 1,34 (ÉT = 0,18). Les modèles de Gopinath (2016), Ashour A (1992) et Shin (1994) ont prédit les capacités de cisaillement des poutres en béton armé de fibres d'acier assez raisonnablement avec des ratio Vprév/Vexp de 1,01 (ÉT = 0,06), 1,07 (ÉT = 0,01) et 1,20 (ÉT = 0,08), respectivement. Un nouveau modèle a été proposé pour prédire les capacités de cisaillement des poutres en béton léger fibré renforcées par des barres longitudinales PRFB. Le modèle proposé prédit bien les capacités de cisaillement des poutres en béton léger (avec des fibres de basalte) avec un rapport Vprév/Vexp de 1,01 (ÉT = 0,05) et celles des poutres en béton léger (avec des fibres de polypropylène) avec un rapport Vprév/Vexp de 0,99 (ÉT = 0,06). Le facteur de liaison et la matrice de liaison d'interface utilisés étaient respectivement 0,75 et 4,18 MPa. En même temps, le modèle proposé prédit bien les capacités de cisaillement des poutres coulées avec des fibres d’acier avec un rapport Vprév/Vexp de 0,9 (ÉT = 0,00) quand le facteur de liaison et la matrice de liaison d'interface utilisés étaient respectivement 1,0 et 6,8 MPa.This study reports on the shear behavior of fiber-reinforced lightweight concrete (FRLWC) beams reinforced with basalt fiber-reinforced polymer (BFRP) bars. Ten beams (150x250x2400 mm) cast with concrete with and without fibers were tested under fourpoint loading configuration until failure occurred. Two beams were cast without fibers and acted as control while the other eight beams were cast with different types and percentages of fiber. The investigated parameters included the fiber type (basalt, polypropylene, and steel fibers), the fibers volume fraction (0, 0.5, and 1.0%), and the beams’ reinforcement ratios (0.95 and 1.37%). Comparison between the experimental results and the analytical models currently available in the literature was performed to assess the applicability of such models for LWC reinforced with BFRP bars. Based on the outcome of the current study, the geometry of fibers played an important role in increasing the number of cracks than those observed in the control beams. The addition of fibers led to a more ductile failure and the rate of crack opening was delayed. Crack width decreased with the increase of the longitudinal reinforcement ratios and the fibers’ volume fractions. Increasing the reinforcement ratio resulted in higher stiffness and decreased its deflection at all stages of loading. Beams cast with 1% of basalt, polypropylene, and steel fibers showed an increase in their shear capacities in compared to control beams about 11, 16, and 63%, respectively. The type of fibers significantly affected the gain in the shear capacities of the beams, which can be attributed to the different physical and mechanical properties of the fibers used such as aspect ratios, lengths, geometries, densities, and their bonding mechanisms. Beams cast with 0.5% steel fibers exhibited higher shear capacities than those cast with basalt and polypropylene fibers by 23 and 16%, respectively, whereas the beams cast with 1% steel fibers showed a gain by 47 and 41%, respectively. The predicted shear capacities according to CSA-S806-12 code provisions were conservative with an average ratio Vpred /Vexp of 0.80 (standard deviation, SD = 0.12) for beams without fibers. Good predictions for the shear capacities of the basalt-fiber reinforced concrete beams (BLWC) were provided by the models derived by Shin (1994) and Gopinath (2016) in which the ratios Vpred /Vexp were 1.34 (SD = 0.09) and 1.35 (SD = 0.07), respectively. Also, the model of Shin (1994) predicted well the shear capacities of the polypropylene-fiber reinforced concrete beams (PLWC) with a Vpred /Vexp ratio of 1.34 and SD of 0.18. The models of Gopinath (2016), Ashour A (1992), and Shin (1994) predicted the shear capacities of steel-fiber reinforced concrete beams (SLWC) fairly reasonable with a Vpred /Vexp ratio of 1.01 (SD = 0.06), 1.07 (SD = 0.01) and 1.20 (SD = 0.08), respectively. A new model was proposed to predict the shear capacities of FRWLC beams reinforced with BFRP longitudinal bars. The proposed model predicted well the shear capacities of BLWC beams with a Vpred /Vexp ratio of 1.01 (SD = 0.05) and those of PLWC beams with a Vpred /Vexp ratio of 0.99 (SD = 0.06). The bond factor and the interface bond matrix used were 0.75 and 4.18 MPa, respectively. The proposed model also predicted well the shear capacities of beams cast with SLWC with a Vpred /Vexp ratio of 0.9 when the bond factor and the interface bond matrix were taken equal to 1.00 and 6.8 MPa, respectively.
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Adhikari, Sudeep. "Mechanical Properties and Flexural Applications of Basalt Fiber Reinforced Polymer (BFRP) Bars." University of Akron / OhioLINK, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=akron1259635900.
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Neela, Subhashini. "Flexural Behavior of Basalt FRP Bar Reinforced Concrete Members With and Without Polypropylene Fiber." University of Akron / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=akron1291084015.
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Lino, Vidal Diego Jesus, and Pacheco Claudio Fernando Quispe. "Análisis y evaluación del uso de fibra de basalto en el concreto para mejorar la resistencia a la corrosión de estructuras sumergidas en las zonas marinas de Pisco." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/653691.
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En el siguiente informe de tesis, se presenta el desarrollo de un concreto especial reforzado con fibra de basalto para evitar la corrosión en los elementos estructurales encontrados en la ciudad de Pisco. Este material es clasificado como polímero utilizado para mejorar las propiedades físicas y mecánicas del concreto. Por ello, los ensayos en probetas estándar de concreto con diferentes porcentajes de este adicionado generan resultados eficientes que comprueban la hipótesis a investigar. Como punto de referencia y comparación también se evaluó un concreto convencional. En ambos casos fueron sometidos a los ensayos de compresión y tracción para medir su resistencia. Además, se realizaron ensayos para medir su durabilidad tales como álcali-sílice y carbonatación. Los resultados generan beneficios en la actividad de la construcción y minimizan los costos económicos surgidos por la pérdida de materiales generado por la corrosión.The following thesis report presents the development of a special concrete reinforced with basalt fiber to prevent corrosion in the structural elements found in the city of Pisco. This material is classified as a polymer used to improve the physical and mechanical properties of concrete. Therefore, the tests in standard concrete specimens with different percentages of this additive generate efficient results that prove the hypothesis to be investigated. As a point of reference and comparison, a conventional concrete was also evaluated. In both cases they were subjected to compression and traction tests to measure their resistance. In addition, tests were carried out to measure its durability such as alkali-silica and carbonation. The results generate benefits in the construction activity and minimize the economic costs arising from the loss of materials generated by corrosion.
Tesis
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Cox, Sarah. "Processing and Characterization of Continuous Basalt Fiber Reinforced Ceramic Matrix Composites Using Polymer Derived Ceramics." Master's thesis, University of Central Florida, 2014. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/6259.
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The need for high performance vehicles in the aerospace industry requires materials which can withstand high loads and high temperatures. New developments in launch pads and infrastructure must also be made to handle this intense environment with lightweight, reusable, structural materials. By using more functional materials, better performance can be seen in the launch environment, and launch vehicle designs which have not been previously used can be considered. The development of high temperature structural composite materials has been very limited due to the high cost of the materials and the processing needed. Polymer matrix composites can be used for temperatures up to 260°C. Ceramics can take much higher temperatures, but they are difficult to produce and form in bulk volumes. Polymer Derived Ceramics (PDCs) begin as a polymer matrix, allowing a shape to be formed and cured and then to be pyrolized in order to obtain a ceramic with the associated thermal and mechanical properties. The use of basalt in structural and high temperature applications has been under development for over 50 years, yet there has been little published research on the incorporation of basalt fibers as a reinforcement in the composites. In this study, continuous basalt fiber reinforced PDCs have been fabricated and tested for the applicability of this composite system as a high temperature structural composite material. The oxyacetylene torch testing and three point bend testing have been performed on test panels and the test results are presented.M.S.M.S.E.
Masters
Materials Science Engineering
Engineering and Computer Science
Materials Science and Engineering
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Banibayat, Pouya. "Experimental Investigation of the Mechanical and Creep Rupture Properties of Basalt Fiber Reinforced Polymer (BFRP) Bars." University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1323229543.
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Espigat-Georger, Aude. "Analyse protéomique de l'assemblage centriolaire et de ses appendices chez la Paramécie : identification et caractérisation d'une protéine des fibres striées, la striatine 6." Paris 6, 2006. http://www.theses.fr/2006PA066259.
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Embley, Michael D. "Damage Tolerance of Buckling-Critical Unidirectional Carbon, Glass,and Basalt Fiber Composites in Co-Cured Aramid Sleeves." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/3185.
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Compression strength after impact tests were conducted on unidirectional composite rods with sleeves. These elements represent local members of open three-dimensional composite lattice structures (e.g., based on isogrid or IsoTruss® technologies). The unidirectional cores composed of carbon, glass, or basalt fiber/epoxy composites were co-cured in aramid sleeves. Sleeve patterns included both bi-directional (unsymmetric) braids and unidirectional spiral wraps with sleeve coverage ranging from nominally half to full. The diameters were nominally 8 and 11 mm (5/16 and 7/16 in). The larger diameter had nominally twice the cross-sectional area, to quantify the effects of scaling. The specimens were long enough to encourage local buckling failure as expected in members of typical composite lattice structures. The unsupported lengths varied from 127 mm (5.0 in) to 160 mm (6.3 in). Specimens were radially impacted at mid-length with energy levels ranging from 0 to 20 J (0 to 14.8 ft-lbs) and tested in longitudinal compression to quantify the effects of local impact damage on the buckling strength. In undamaged specimens, sleeve type and sleeve coverage have no effect on the ultimate compression strength of carbon, glass, or basalt composites (7% or less standard deviation for each material). When impacted, the influence of sleeve type and sleeve coverage varies with the type of fiber in the unidirectional core. Sleeve type and coverage did not affect the compression strength after impact for fiberglass composites. On the other hand, both carbon and basalt composites exhibited improved performance with braided (vs. spiral) sleeves (up to 34% stronger) and full (vs. half) coverage (up to 38% stronger). The compression strength of carbon configurations decreases with increasing impact energy regardless of sleeve type or coverage. The higher flexibility of glass and basalt composites, however, allowed some configurations to maintain the same compression strength after impact as their undamaged counterparts, at lower impact energy levels. Doubling cross-sectional area of basalt composites significantly improves the stiffness and compression strength after impact, more than doubling the impact energy required to achieve the same compression strength.
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Pirri, Alessandra. "Attività sperimentale su materiali ecosostenibili fibrorinforzati con tessuti a base di fibre di basalto per applicazioni civili." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/3021/.
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LAPENA, MAURO H. "Estudo do comportamento mecânico de cilindros de compósito epóxi/fibra de basalto em ensaios hidrostáticos." reponame:Repositório Institucional do IPEN, 2017. http://repositorio.ipen.br:8080/xmlui/handle/123456789/28046.
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O objetivo deste trabalho foi estudar o comportamento mecânico de cilindros de compósito polimérico reforçado com fibras. Para isso, foram produzidos cilindros com extremidades abertas reforçados com fibra de basalto e fibra de vidro, utilizando a técnica de enrolamento filamentar (filament winding). Estes cilindros foram submetidos a ensaio hidrostático com carregamento circunferencial, ensaio de ruptura de anel (split disk test) e ensaio de resistência ao cisalhamento interlaminar (ILSS). Uma placa do compósito de fibra de basalto foi produzida por enrolamento filamentar, para caracterização por ensaio de resistência à tração. Todos cilindros submetidos ao ensaio hidrostático apresentaram fratura localizada em uma faixa de altura do cilindro, com extensas delaminações das camadas circunferenciais. Os compósitos epóxi/fibra de basalto superaram ou igualaram os de compósito epóxi/fibra de vidro nas comparações entre resultados dos valores das propriedades mecânicas avaliadas, nas porcentagens: resistência à tração aparente de ruptura de anel em 45% e 43% em resistência específica; ILSS, em 11%; resistência/tensão de membrana de ruptura no ensaio hidrostático, em 55%.
Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP
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Hrubý, Petr. "Využití čedičových vláken v alkalicky aktivovaných materiálech." Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2018. http://www.nusl.cz/ntk/nusl-377316.
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Alkali activated materials (AAMs) represent construction materials with a huge potential especially because of environmental and economic aspects but sufficient mechanical properties as well. A fibre or fabric reinforcement of the AAMs could support more widespread application potential due to the mechanical properties, fracture toughness or composite durability improvement. Various alkaline activators were used for a blast furnace slag (BFS) activation to produce a suitable matrix for basalt fibres (BF) implementation in this thesis. The BFs represent applicable reinforcing material because of its favourable mechanical and thermal properties. Still, the utilization of BFs in the AAMs is quite limited due to the fibres low chemical stability under the alkaline conditions. Accelerated leaching tests with a determination of basalt fibres chemical composition same as tensile strength change using various analytical techniques (XRD, XPS, SEM-EDX, ICP-OES) have confirmed these assumptions. An influence of basalt fabric reinforcement in one or more layers on the mechanical properties was determined with the meaning of the compressive and flexural strengths. The fibre/matrix adhesion and transition zone properties were studied using SEM-EDX and pull-out tests as well because they are crucial parameters for the composite material reinforcement efficiency.
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Elgabbas, Fareed Mahmoud. "Development and structural testing of new basalt fiber-reinforced-polymer (BFRP) bars in RC beams and bridge-deck slabs." Thèse, Université de Sherbrooke, 2016. http://hdl.handle.net/11143/8734.
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L'avancée de la technologie des PRF a suscité l'intérêt de l'introduction de nouvelles fibres, comme la fibre de basalte, qui a un potentiel d'offrir une solution efficace, lorsqu’utilisée dans les structures en béton, soit sur la résistance à la corrosion, la durabilité et la rentabilité. En outre, les codes et les guides disponibles, ne fournissent pas de recommandations pour l'utilisation de barres en PRFB puisque les recherches passées dans ce domaine sont limitées. Donc, des travaux de recherche sont nécessaires pour caractériser et comprendre le comportement des barres de PRFB dans les éléments en béton armé. En conséquence, les objectifs principaux sont d'évaluer les caractéristiques à court et long terme des barres de PRFB nouvellement développées, ainsi que d'évaluer les performances structurales de ces nouvelles barres comme renforcement interne dans les poutres et les dalles de pont et d'introduire ce nouveau renforcement dans les codes et les guides de dimensionnement. Les tests expérimentaux ont été faits en trois parties. La première partie porte sur le développement de trois nouvelles barres et tendons en PRFB pour déterminer leurs propriétés physiques et mécaniques. Les performances à long terme et de durabilité ont été réalisées en conditionnant les barres de PRFB dans une solution alcaline simulant les conditions humides dans le béton pour déterminer la compatibilité comme renforcement interne dans les éléments en béton. Par la suite, les propriétés ont été déterminées et comparées avec des spécimens non conditionnés (référence). La seconde partie a porté sur sept dalles de pont en béton armé grandeur réelle avec les bords restreints, simulant les tabliers de pont les plus utilisés en Amérique du Nord, pour évaluer la performance des dalles renforcées de PRFB et d'acier. Les dalles mesurent 3000 mm de long × 2500 mm de large × 200 mm d'épaisseur. Les dalles ont été testées jusqu'à la rupture sous une charge concentrée au centre de celles-ci simulant l'empreinte d'une roue d'un camion. Les capacités en poinçonnement sont prédites en utilisant les exigences réglementaires disponibles, et sont comparées aux résultats expérimentaux. La troisième partie de cette étude portait sur les essais de 14 poutres en béton de 3100 mm de long × 200 mm de large × 300 mm de profond pour examiner le comportement en flexion et les performances en service des barres de PRFB avec deux états de surfaces: fini sablé et crénelé. Les poutres ont été testées en flexion en quatre points avec une portée libre de 2700 mm jusqu'à la rupture. Les résultats sont introduits et discutés en terme : du comportement de la fissuration, des flèches, de la capacité en flexion et des modes de ruptures. De plus, le coefficient d'adhérence (kb) des barres de PRFB est déterminé et comparé avec les recommandations des codes et guides actuels. Les résultats sont introduits et discutés en terme : du comportement de la fissuration, des flèches, de la capacité en flexion et des modes de ruptures. De plus, le coefficient d'adhérence des barres de PRFB est déterminé et comparé avec les recommandations des codes et guides actuels. Les résultats de l'étude concluent sur la viables pour la production des barres de PRFB pour respecter les exigences des codes actuelles. Également, les résultats d'essai indiquent que les barres de PRFB ont de bonnes propriétés mécaniques et peuvent être placées dans la même catégorie que les barres de PRFV, soit grade III. De plus, le comportement des poutres et des dalles de pont renforcées de PRFB est similaire que pour un renforcement en PRFV et PRFC et les exigences réglementaires sont applicables pour les barres de PRFB.Abstract: The advances in fiber-reinforced-polymer (FRP) technology have spurred interest in introducing new fibers, such as basalt FRP (BFRP), which has the potential to offer an efficient solution when implemented in concrete structure, such as corrosion resistant, durable and cost-effective. Furthermore, the available design codes and guides do not provide any recommendations for the use of BFRP bars since fundamental studies and relevant applications are still limited. Therefore, investigations are needed to characterize and understand the behavior of BFRP bars in concrete members. Consequently, the main objectives of this experimental investigation are to evaluate the short- and long-term characteristics of newly developed BFRP bars, as well as evaluate the structural performance of these new bars as internal reinforcement for concrete beams and bridge-deck slabs to introduce these new reinforcing bars to the design codes and guides. The experimental tests were completed through three parts. The first part was conducted on three newly developed BFRP bars and tendons to investigate their physical and mechanical properties. Durability and long-term performance were assessed by conditioning the BFRP bars in an alkaline solution simulating the moist concrete environment to determine their suitability as internal reinforcement for concrete elements. Thereafter, the properties were assessed and compared with the unconditioned (reference) values. The second part of this study was conducted on seven full-scale edge-restrained concrete bridge-deck slabs simulating actual slab-on-girder bridge-deck that is commonly used in North America to evaluate the performance of concrete bridge-deck slabs reinforced with BFRP and steel bars. The deck slabs measured 3000 mm long × 2500 mm wide × 200 mm deep. The slabs were tested up to failure under single concentrated load acting on the center of each slab simulating the footprint of sustained truck wheel load. The punching shear capacities were predicted using the available provisions, and compared with the experimental results. The third part of this study included testing of fourteen concrete beams of 3100 mm long × 200 mm wide × 300 mm deep to investigate the flexural behavior and serviceability performance of sand-coated and ribbed BFRP bars in concrete beams. The beams were tested under four-point bending over a clear span of 2700 mm until failure. The results are introduced and discussed in terms of cracking behavior, deflection, flexure capacity, and failure modes. In addition, the bond-dependent coefficient (kb) of the BFRP bars was determined and compared with the recommendations of the current FRP design codes and guides. The findings of this study concluded the feasibility of producing BFRP bars meet the requirements of the current FRP standards. Also, the test results revealed that the BFRP bars had good mechanical behavior and could be placed in the same category as grade II and grade III GFRP bars. Moreover, the behavior of the concrete bridge-deck slabs and beams reinforced with BFRP bars was quite similar to the counterparts reinforced with glass- and carbon-FRP bars and the available FRP provisions are applicable for BFRP bars. The beam test results yielded an average bond-dependent coefficient (kb) of 0.76±0.03 and 0.83±0.03 for the sand-coated and ribbed BFRP bars, respectively.
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Attia, Karim. "Experimental and numerical investigation of the flexural behavior of RC slabs reinforced with BFRP bars with and without basalt fibers." Master's thesis, Université Laval, 2017. http://hdl.handle.net/20.500.11794/27744.
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Cette étude évalue à la fois expérimentalement et numériquement le comportement en flexion des dalles de béton renforcées avec des barres en PRF de basalte avec et sans fibres de basalte. Les paramètres étudiés comprenaient les dosages des fibres de basalte utilisés dans le mélange de béton et les ratios du renforcement longitudinale dans les poutres. Tout d'abord, l'effet de différents dosages des fibres sur les propriétés mécaniques du béton a été évalué. Cela a été suivi par des essais de flexion qui ont été menés sur huit dalles à grande échelle chargées en quatre points. Des modèles numériques en éléments finis (ÉF) ont été élaborés à l'aide du logiciel ATENA® pour prédire le comportement en flexion des spécimens testés. Pour les résultats expérimentaux, l'augmentation du dosage des fibres de basalte a amélioré la résistance à la compression et le module de rupture du béton. Les dalles avec des dosages plus élevés de fibres ont montré une augmentation du nombre de fissures et une augmentation de leurs capacités ultimes. L'augmentation du dosage des fibres conduisait à une diminution de la ductilité des dalles testées. Cependant, toutes les dalles présentaient des indices de ductilité supérieurs à la valeur minimale exigée par la norme CAN/CSA-S6-06. Le ratio de renforcement longitudinal a eu un léger effet sur la charge de fissuration. Cependant, il contrôlait les flèches des dalles testées. Ces résultats étaient en accord avec les résultats rapportés dans la littérature pour les dalles renforcées de barres d'acier et fabriquées en béton renforcé de fibres d'acier. Un très bon accord entre les valeurs numériques et les résultats expérimentaux était obtenu. Les modèles ÉF simulaient bien le comportement en flexion des dalles en termes de charges de fissuration, des capacités, des flèches, et des configurations de fissure. Le modèle d'engagement variable a réussi à simuler le comportement du béton renforcé avec des fibres de basalte. Compte tenu du fait que ce modèle a été initialement développé pour les mélanges de béton renforcé avec des fibres d’acier, on pourrait déduire que les bétons fibrés de basalte ont un comportement comparable à celui des bétons fibrés d’acier.This study assesses both experimentally and numerically the flexural behaviour of concrete slabs reinforced with basalt-fiber reinforced polymer (BFRP) bars cast with and without basalt fiber-reinforced concrete (BFRC). The parameters investigated included the volume fractions of the basalt fibers used in the concrete mix and the ratios of the longitudinal tensile reinforcement in the beams. First, the effect of different fiber volume fractions on the mechanical properties of concrete was assessed. This was followed by flexural tests that were conducted on eight large-scale slabs under four-point load configuration. A finite element model (FEM) was developed using ATENA® to simulate the flexural behaviour of the tested specimens. Based on the experimental results, increasing the fiber volume fraction enhanced the compressive strength and modulus of rupture of concrete. Slabs with higher dosages of fibers showed increased number of cracks and an increase in their cracking and ultimate capacities. Increasing the fiber content led to decreased ductility in the tested slabs. However, all slabs showed a ductility index that exceeded the minimum value stated by CAN/CSA-S6-06. The longitudinal reinforcement ratio had a slight effect on the cracking load. However, it governed the deflection of the tested slabs. These results were in agreement with the test results reported in the literature for slabs reinforced with steel bars and cast with conventional steel fiber-reinforced concrete (SFRC). A very good agreement between the numerical and the experimental results was obtained. The FEM predicted well the flexural behaviour of the slabs in terms of cracking loads, load-carrying capacities, deflections, and crack pattern. The Variable Engagement Model (VEM) successfully captured the behavior of the BFRC. Considering the fact that the model was initially developed for SFRC mixes, it could be concluded that BFRC has a comparable behavior to SFRC.
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Motoc, Dana. "Development of green composites based on epoxidized vegetable oils (EVOs) with hybrid reinforcements: natural and inorganic fibers." Doctoral thesis, Universitat Politècnica de València, 2017. http://hdl.handle.net/10251/90399.
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The main aim of this work id to provide integral methods to predict and characterize the properties of composite structures based on hybrid polymers and reinforcements, that could lead to useful results from an industrial point of view. This is addressed, if possible, by theoretical predictions of the effective properties by using the available experimental data.
The first part is focused on the scientific achievements of the author that allowed a quantitative characterization of the main effective properties of several composite architectures from hybrid polymers and reinforcements, based on bio matrices, tailor-made matrices and different theoretical and simulation methods using computer software to allow good comparison. The second part defines the future research lines to continue this initial investigation.
The main objectives are clearly defined to give the reader a sound background with the appropriate concepts that are specifically discussed in the following chapters. As a main objective, this research work makes a first attempt to provide a systematic analysis and prediction of composite hybrid structures.El objetivo general del trabajo es proporcionar medios integrales para predecir y caracterizar las propiedades de las estructuras de compuestos basados en polímeros y refuerzos híbridos, principales que pueden producir resultados de utilidad práctica simultáneamente. Esto se logra comparando, siempre que sea posible, las predicciones teóricas de las propiedades efectivas con los datos experimentales disponibles. Una primera parte se ocupa de los logros científicos del autor que permitieron caracterizar cuantitativamente las principales propiedades efectivas de las arquitecturas de compuestos basados en polímeros y refuerzos híbridos, basados en matrices bio, auto-desarrollados y diferentes métodos teóricos y de simulación por ordenador utilizados para la comparación. La segunda parte identifica las orientaciones futuras para la evolución y desarrollo de la ciencia y la investigación. Los objetivos generales fueron subrayados y concisos para dar al lector una visión previa de los conceptos que serán discutidos específicamente en los siguientes capítulos. Indirectamente, apuntan hacia uno de los objetivos principales de este trabajo, a saber, proporcionar una dirección para el análisis sistemático de materiales compuestos a base de refuerzos híbridos.
L'objectiu general d'aquest treball es proporcionar els mitjos integrals per tal de predir i caracteritzar les propietats d'estructures de compòsits basats en polímers i reforçaments híbrids, que poden produir resultats amb utilitat pràctica simultàniament. Aquest objectiu s'aconsegueix comparant, sempre que és possible, les prediccions teòriques de les propietats efectives amb les dades experimentals disponibles. Una primera part es centra en els temes científics en què ha treballat l'autor que han permès caracteritzar quantitativament les principals propietats efectives de les arquitectures de compòsits basades en polímers i reforçaments híbrids, derivats de matrius bio, auto-desenvolupats i diferents mètodes teòrics i de simulació informàtica per a una correcta comparació. La segona part identifica les orientacions futures per tal d'establir l'evolució i desenvolupament de la ciència i investigació lligada a la temàtica de la tesi. Els objectius generals han sigut clarament definits per tal de donar-li al lector una visió prèvia i sòlida dels conceptes que es discuteixen en capítols venidors. Indirectament, apunten cap a un dels objectius principals d'aquest treball, a saber, proporcionar una direcció per a l'anàlisi sistemàtica de materials compòsits a base de polímers i reforçaments híbrids.
Motoc, D. (2017). Development of green composites based on epoxidized vegetable oils (EVOs) with hybrid reinforcements: natural and inorganic fibers [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/90399
TESIS
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Rask, Moa. "Product development of a fire hose basket that promotes ergonomics for firefighters." Thesis, Högskolan i Borås, Akademin för textil, teknik och ekonomi, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-21267.
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This report comprises a product development of an ergonomically designed hose basket that can be used by the firefighters when storing or carrying a fire hose. A study on ergonomics in the profession as a firefighter conducted by the Research Institutes of Sweden (RISE) showed that fire hose deployment was very physically exhausting. This study also revealed that some load may become too heavy and difficult to carry due to the design of the equipment. Injury to the user during lifting is common within the profession. Therefore there is a need for equipment that is more ergonomically designed. The project follows a product development phase that includes market research and feasibility study which was accomplished by a literature study and through study visits and interviews at fire stations. A common type of hose basket was used as the starting point for the project. This hose basket is in this report referred as "Skövde basket" and was considered heavy and un-ergonomic to carry, especially for shorter people. From the gathered information a ‘house of quality’ and a two-step idea generation was created. Several concepts that were made opposed the Skövde basket in an evaluation matrix. A material selection using a program, CES Selector 3.2 was made on the winning concept that became a hose basket which is carried under the arm. The hose basket was then constructed in the program Creo Parametric 4.0 and detail drawings were created. A prototype was then made and tested by firefighters of both sexes and of different heights. The results pointed out improvements and deteriorations from the Skövde basket. The deterioration was that the basket became more difficult to pack, which was due to the reduced number of bars. Improvements were noticed on lift height; significant increase on lift height facilitated easy carrying by shorter individuals.Denna rapport omfattar en produktutveckling av en ergonomiskt utformad slangkorg som kan användas av räddningstjänsten då brandslang ska placeras ut. Enligt en studie kring ergonomi inom räddningstjänsten gjord av Research Institutes of Sweden, RISE, ansåg många brandmän att slangutläggning var mycket fysiskt ansträngande. Syftet är att främja ergonomi inom brandmannayrket. Trots de fysiska kraven hos brandmän, kan vissa laster bli för tunga och svåra att bära på grund av utrustningens utformning. Därför behövs utrustning som är mer ergonomiskt utformad. Projektet följer övergripligt en produktutvecklingsfas där det ingår dels en marknadsundersökning och en förstudie vilket gjordes genom en litteraturstudie, intervjuer och studiebesök på brandstationer. En vanlig variant av slangkorg användes som utgångspunkt för projektet, denna slangkorg kallas i rapporten för ”Skövdeväskan” och ansågs tung och oergonomisk att bära, framför allt för kortare personer. Utifrån den information som samlats in gjordes ett kvalitetshus och en tvåstegs idégenerering där koncept togs fram. Koncepten ställdes mot varandra och mot Skövdeväskan i en konceptvalsmatris. Materialval med programmet CES Selector 3.2 gjordes på det vinnande konceptet som blev en slangkorg som bärs under armen. Slangkorgen modellerades sedan i programmet Creo Parametric 4.0 och detaljritningar skapades. En prototyp konstruerades och denna testades av brandmän av båda könen och av olika längd. Testpersonerna fick därefter göra en utvärdering som visade på både förbättringar och försämringar jämfört med Skövdeväskan. Försämringar som uppkom var att korgen blev mer svårpackad vilket berodde på det reducerade antalet stödstänger i ramen. Förbättringar gjordes på lyfthöjd vilket underlättade framför allt för de kortare personerna.
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DeGomez, Tom. "Guidelines for Thinning Ponderosa Pine for Improved Forest Health and Fire Prevention." College of Agriculture and Life Sciences, University of Arizona (Tucson, AZ), 2006. http://hdl.handle.net/10150/146952.
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7 pp.Preventing catastrophic stand replacing events are best accomplished through thinning. Lower tree densities result in greater tree growth. Stands with lower tree densities have greater plant diversity. Determining stand conditions will provide a baseline for formulating a plan to improve stand conditions. Thinning around individual trees can improve individual tree health reducing the likelihood of damage from bark beetles, fire or drought.
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Poisbeau, Vianney. "Modélisation de la durabilité des PRFB et PRFV en béton humide basée sur la dégradation fibre/matrice." Mémoire, Université de Sherbrooke, 2017. http://hdl.handle.net/11143/10981.
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L’étude de la durabilité des polymères renforcés de fibres (PRF) dans le béton est un enjeu majeur de leur développement en tant qu’alternative aux armatures d’acier soumises à la corrosion. La simulation à long terme de la solution interstitielle est le plus souvent assurée par l’immersion des barres de composite dans des solution acides ou basiques, dans lesquelles la température agit comme accélérateur. La littérature propose principalement des analyses physiques et mécaniques des PRF dans leur globalité, sans forcément concentrer l’étude sur chaque composant. C’est donc l’objectif de cette étude de vouloir suivre l’impact des solutions corrosives sur un large panel de matériaux, à la fois sur les résines pures, les fibres, et les composites qui en découlent.
Pour cela, des matériaux couramment utilisés en génie civil ont été choisis : deux types de fibres synthétiques (verre et basalte) avec différents agents d’ensimage, trois types de résines thermodurcissables (polyuréthane, époxy et vinylester), et donc six types de composites (3 PRFV et 3 PRFB) fabriqués par pultrusion. Les échantillons ont été conditionnés de façon accélérée à 24°C, 40°C et 65°C dans l’eau et en solution alcaline jusqu’à 10 jours pour les fibres, et entre 2 et 3 mois pour les résines et composites. Des tests physiques et mécaniques ont été menés, tels qu’un suivi de l’absorption d’eau, des mesures de la température de transition vitreuse par DSC, des analyses thermiques et infrarouges et des observations microscopiques.
Contrairement à la solution acide, la solution alcaline attaque la fibre de basalte par piquration de façon hétérogène, et aucune espèce chimique n’est dissoute. La durabilité des fibres dans l’alkali dépend de l’agent d’ensimage, une même fibre n’ayant pas le même comportement en traction ni en microscopie selon son traitement de surface.
L’eau provoque dans la résine un réarrangement moléculaire visible par DSC, qui ressemble à une plastification irréversible mais qui ne peut pas être une hydrolyse selon l’analyse FTIR. Cela s’explique par la création de deux phases de résine, confirmé dans la littérature par l’observation de deux pics de Tg par DMA, et par la théorie des volumes libres par ATM. La relation de Kelley-Bueche simplifiée permet de conclure que l’absorption de solvant, eau ou alkali, est le facteur critique initiant la dégradation de la résine.
Une loi fickienne permet d’approximer la diffusion d’eau dans le polymère et le composite, ce dernier diffusant plus fortement que la résine pure, même lorsqu’aucun vide ou descellement à l’interface n’est constaté. Une interphase aux propriétés modifiées est en fait créée autour de la fibre par l’interaction de la résine avec l’ensimage et l’eau. Une analyse par éléments finis, ainsi que des résultats par AFM et micro-TA de la littérature permettent d’estimer que cette zone diffuse cinq fois plus que la résine pure et mesure entre 1 et 6 micromètres selon les matériaux.
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Nishizaka, Takahiro. "Effects of Exposure to Mild Hyperbaric Oxygen on Skeletal Muscle Fibers, Epidermal Basal Cells, and Skin Pigmentation." Kyoto University, 2014. http://hdl.handle.net/2433/193555.
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Kyoto University (京都大学)0048
新制・論文博士
博士(人間・環境学)
乙第12883号
論人博第40号
新制||人||169(附属図書館)
26||論人博||40(吉田南総合図書館)
31601
(主査)教授 石原 昭彦, 教授 船橋 新太郎, 教授 林 達也, 准教授 神﨑 素樹, 准教授 久代 恵介
学位規則第4条第2項該当
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Samper, Madrigal María Dolores. "Desarrollo y optimización de 'green composites' basados en matrices derivadas de aceites vegetales modificados y refuerzos de fibras minerales." Doctoral thesis, Universitat Politècnica de València, 2015. http://hdl.handle.net/10251/52602.
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[EN] In recent years, the sensitiveness of society about the conservation of environment has increased; this has promoted the development of polymeric materials derived from renewable resources. These new polymeric materials have good properties and can be used for the development of 'green composites'.
The main objective of thisdoctoral thesis is the development and optimization of 'green composites', using matrices derived from epoxidized vegetable oils and mineral fibers, which have similar properties to glass fibers.
The matrices used are based on epoxidized linseed oil (ELO) and epoxidized soybean oil (ESBO), and two types of crosslinking agent. One is a eutectic system of phthalic anhydride (PA), 23.8 wt%, and maleic anhydride (MA), 76.2 wt%, with a melting temperature of 48.3 °C. The other crosslinking agent was methyl nadic anhydride (MNA) which is liquid at room temperature.
Thermoset materials obtained show that MNA crosslinker provides materials with improved mechanical and thermomechanical properties when compared to thermoset materials obtained with the PA/MA system.
Interface phenomena of composites based on ELO-MNA and ESBO-MNA with mineral fibers from basalt and slate was evaluated by the single fiber fragmentation test (SFFT) to assess fiber-matrix interactions on the selected composites
Basalt fibers were modified with two amino-silanes ((3-aminopropyl) trimethoxysilane and [3-(2-aminoethylamino)propyl]trimethoxysilane) and two glycidyl-silanestrimethoxy[2-(7-oxabicyclo[4.1.0]hept-3-yl)ethyl]silane and (3-glycidyloxypropyl) trimethoxysilane).
SFFT determined that the interfacial shear stress (¿) of basalt fibers and ELO-MNA and ESBO-MNA matrices, is higher with basalt fibers treated with amino-silane [3-(2-aminoethylamino)propyl]trimethoxysilane and glycidyl silane trimethoxy[2-(7-oxabicyclo[4.1.0]hept-3-yl)ethyl]silane with both matrices.
By considering the results obtained with the SFFT technique, composite laminates containing basalt fabrics modified with silanes [3-(2-aminoethylamino)propyl] trimethoxysilane and trimethoxy[2-(7-oxabicyclo[4.1.0]hept-3-yl)ethyl]silane were manufactured. These composite laminates offer good mechanical properties as expected on the base of SFFT results, with optimum results for composites with basalt fabric previously modified with([trimethoxy [2-(7-oxabicyclo [4.1.0] hept- 3-yl) ethyl] silane.
Slate fibers were treated with an amino-silane[3-(2-aminoethylamino)propyl]trimethoxysilane, a glycidyl-silane trimethoxy[2-(7-oxabicyclo [4.1.0] hept-3-yl)]-silane, a zirconate (zirconium(IV)bis(dietilcitrato)dipropóxido) and a titanate (titanium (IV)(triethanolaminato)isopropoxide and ELO-MNAwas selected as matrix because it offers has good mechanical properties.
The mechanical characterization of composites made from slate fabrics revealed that the best results are obtained using glycidyl silane and titanate coupling agents.
Green composite made withslate fiber modified with trimethoxy[2-(7-oxabicyclo[4.1.0]hept-3-yl)ethyl]silane and ELO-MNA resin offers the best mechanical properties. This material has a flexural strength of 402.1 MPa, flexural modulus of 19.7 GPa, a tensile strength of 359.1 MPa and a Young's modulus of 25.6 GPa. These good properties allow it to compete with conventional composites manufactured with glass fiber.[ES] En los últimos años ha aumentado la sensibilidad de la sociedad ante la conservación del medio ambiente, lo que ha llevado al desarrollo de materiales poliméricos derivados de recursos renovables. Estos nuevos materiales poliméricos presentan propiedades tales que pueden usarse para el desarrollo de 'green composites'. El principal objetivo de esta tesis doctoral es el desarrollo y optimización de 'green composites', utilizando matrices derivadas de aceites vegetales epoxidados y fibras minerales, que presentan propiedades similares a las fibras de vidrio. Las matrices utilizadas se basan en aceite de linaza epoxidado (ELO) y aceite de soja epoxidado (ESBO), y se han utilizado dos tipos de agentes entrecruzantes. Uno es una mezcla de anhídrido ftálico (PA), 23,8% en peso, y anhídrido maleico (MA), 76,2 % en peso, que presenta una transformación eutéctica al porcentaje dado y cuya temperatura de fusión ocurre a 48,3 ºC. El otro agente entrecruzante utilizado es anhídrido metil nádico (MNA) que es líquido a temperatura ambiente. Los materiales termoestables obtenidos ponen de manifiesto que el agente entrecruzante MNA proporciona materiales con mejores propiedades mecánicas y termomecánicas que los obtenidos con la mezcla de PA/MA. A partir de las resinas basadas en ELO-MNA y ESBO-MNA y fibras de basalto y pizarra, se realiza la evaluación de la entrecara de los composites mediante el test de fragmentación de una sola fibra (SFFT) y posteriormente se realiza y evalúa los materiales compuestos seleccionados. Las fibras de basalto se modifican con dos amino-silano (3-aminopropil)trimetoxisilano y [3-(2-aminoetilamino)propil]trimetoxisilano) y dos glicidil-silano trimetoxi[2-(7-oxabiciclo[4.1.0]hept-3-il)etil]silano y (3-glicidiloxipropil) trimetoxisilano. El SFFT determina que el esfuerzo cortante en la entrecara (¿), de las fibras de basalto y las matrices ELO-MNA y ESBO-MNA, es más elevado con las fibras tratadas con el amino-silano [3-(2-aminoetilamino)propil]trimetoxisilano y con el glicidil-silano trimetoxi[2-(7-oxabiciclo[4.1.0]hept-3-il)etil]silano con ambas matrices. Debido a los resultados obtenidos con la técnica SFFT se realizan materiales compuestos utilizando tejidos de basalto modificados con los silanos [3-(2-aminoetilamino)propil]trimetoxisilano y trimetoxi[2-(7-oxabiciclo[4.1.0]hept-3-il)etil]silano. De esta forma se obtienen materiales compuestos con buenas propiedades mecánicas y se valida la técnica SFFT, ya que el material compuesto con mejores propiedades es realizado con los tejidos de basalto modificado con ([trimetoxi[2-(7-oxabiciclo[4.1.0]hept-3-il)etil]silano, tal y como se predijo con la técnica SFFT. Las fibras de pizarra fueron tratadas con un amino-silano ([3-(2-aminoetilamino)propil]trimetoxisilano), un glicidil-silano trimetoxi[2-(7-oxabiciclo[4.1.0]hept-3-il)etil]silano, un zirconato (zirconio(IV)bis(dietilcitrato)dipropóxido) y un titanato (titanio(IV)(trietanolaminato)isopropóxido y se seleccionó como matriz ELO-MNA debido a sus buenas propiedades mecánicas.La caracterización mecánica de los composites realizados con tejidos de pizarra reveló que los mejores resultados se obtienen utilizando los agentes de acoplamiento glicidil-silano y titanato. El 'green composite' que presenta las mejores propiedades mecánicas es el realizado con fibra de pizarra modificada con trimetoxi[2-(7-oxabiciclo[4.1.0]hept-3-il)etil]silano y la resina ELO-MNA. Este material presenta una resistencia a flexión de 402,1 MPa, un módulo a flexión de 19,7 GPa, la resistencia a tracción es de 359,1 MPa y el Módulo de Young es de 25,6 GPa. Las buenas propiedades resistentes que presenta le permite poder sustituir a composites tradicionales realizados con fibra de vidrio.
[CAT] En els últims anys ha augmentat la sensibilitat de la societat davant la conservació del medi ambient, el que ha portat al desenvolupament de materials polimèrics derivats de recursos renovables. Aquests nous materials polimèrics presenten propietats tals que poden usar-se per al desenvolupament de ''green composites''. El principal objectiu d'aquesta tesi doctoral és el desenvolupament i optimització de ''green composites'', utilitzant matrius derivades d'olis vegetals epoxidats i fibres minerals, que presenten propietats similars a les fibres de vidre. Les matrius utilitzades es basen en oli de llinosa epoxidat (ELO) i oli de soia epoxidat (ESBO), i s'han utilitzat dos tipus d'agents d'entrecreuament. Un és una barreja d'anhídrid ftàlic (PA), 23,8 % en pes, i anhídrid maleic (MA), 76,2 % en pes, que presenta una transformació eutèctica al percentatge donat i la seua temperatura de fusió passa a 48,3 ºC. L'altre agent d'entrecreuament utilitzat és anhídrid metil nàdic (MNA) que és líquid a temperatura ambient. Els materials termostables obtinguts posen de manifest que l'agent d'entrecreuament MNA proporciona materials amb millors propietats mecàniques i termomecàniques que els obtinguts amb la mescla de PA/MA. A partir de les resines basades en ELO-MNA i ESBO-MNA i fibres de basalt i llicorella, es va realitzar l'avaluació interfacial dels 'composites' utilizant el test de fragmentació d'una única fibra (SFFT) i posteriorment es van fabricar i avaluar els materials compostos seleccionats. Les fibres de basalt es van modificar amb dos amino-silans ((3-aminopropil)trimetoxisilà i [3-(2-aminoetilamino)propil]trimetoxisilà) i dos glicidil-silans trimetoxi[2-(7-oxabicicle[4.1.0]hept-3-il)etil]silà i 3-glicidiloxipropil)trimetoxisilà. El SFFT va determinar que l'esforç de tall interfacial (¿), de les fibres de basalt i les matrius ELO-MNA i ESBO-MNA, és més elevat amb les fibres tractades amb l'amino-silà [3-(2-aminoetilamino)propil]trimetoxisilà i amb el glicidil-silà ([trimetoxi[2-(7-oxabicicle[4.1.0]hept-3-il)etil]silà amb ambdues matrius. Degut als resultats obtinguts amb la tècnica SFFT es van realitzar materials compostos utilitzant teixits de basalt modificats amb els silans [3-(2-aminoetilamino)propil]trimetoxisilà i trimetoxi[2-(7-oxabicicle[4.1.0]hept-3-il)etil]silà. D'aquesta forma s'obtenen materials compostos amb bones propietats mecàniques i es va validar la tècnica SFFT, ja que el material compost amb millors propietats va ser realitzat amb els teixits de basalt modificat amb trimetoxi[2-(7-oxabicicle[4.1.0]hept-3-il)etil]silà, tal com es va predir amb la tècnica SFFT. Les fibres de llicorella van ser tractades amb un amino-silà ([3-(2-aminoetilamino)propil]trimetoxisilà), un glicidil-silà trimetoxi[2-(7-oxabicicle [4.1.0]hept-3-il)etil]silà, un zirconat (zirconi(IV)bis(dietilcitrat) dipropòxid) i un titanat (titani(IV)(trietanolaminato)isopropòxid i es va seleccionar com a matriu ELO-MNA a causa de les seues bones propietats mecàniques. La caracterització mecànica dels 'composites' realitzats amb teixits de llicorella va revelar que els millors resultats s'obtenen utilitzant els agents d'acoblament glicidil-silà i titanat. El 'green composite' que presenta les millors propietats mecàniques és el realitzat amb fibra de llicorella modificada amb trimetoxi[2-(7-oxabicicle[4.1.0]hept-3-il)etil]silà i la resina ELO-MNA. Aquest material presenta una resistència a flexió de 402,1 MPa, un mòdul a flexió de 19,7 GPa, la resistència a tracció és de 359,1 MPa i el mòdul de Young és de 25,6 GPa. Les bones propietats resistents que presenta li permeten poder substituir a 'composites' tradicionals realitzats amb fibra de vidre.
Samper Madrigal, MD. (2015). Desarrollo y optimización de 'green composites' basados en matrices derivadas de aceites vegetales modificados y refuerzos de fibras minerales [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/52602
TESIS
Premiado
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McKee, James. "Development and Characterization of Nanoparticlee Enhancements in Pyrolysis-Derived High Temperature Composites." Master's thesis, University of Central Florida, 2013. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/6320.
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Thermal protection systems, which are commonly used to protect spacecraft during atmospheric entry, have traditionally been made of materials which are traditionally high in manufacturing costs for both the materials needed and the manufacturing complexity, such as carbon-carbon composites and aerogels. In addition to their manufacturing costs, these materials are also limited in their strength, such as PICA, in a way that necessitate the use of tiles as opposed to single structures because they are not capable of supporting larger structures. The limitations of polymer reinforced composites have limited their entry into these applications, except for pyrolyzed composite materials, such as carbon-carbon and ceramic composites. These materials have been successfully demonstrated their utility in extreme environments, such as spacecraft heat shields, but their high costs and the difficulty to manufacture them have limited their use to similarly high performance applications where the costs are justifiable.
Previous work by others with "fuzzy fiber" composites have shown that aligned carbon nanotubes (CNTs) grown on fibers can improve their thermal conductivity and wettability. To this end vertically aligned CNTs were studied for their potential use, but found to be difficult to process with current conventional techniques. A composite material comprised of basalt, a relatively new reinforcing fiber, and phenolic, which has been used in high-temperature applications with great success was made to attempt to create a new material for these applications. To further improve upon the favorable properties of the resulting composite, the composite was pyrolyzed to produce a basalt-carbon composite with a higher thermal stability than its pristine state. While testing the effects of pyrolysis on the thermal stability, a novel technique was also developed to promote in-situ carbon nanotube growth of the resulting basalt-carbon composite without using a monolithic piece of cured phenolic resin in place of the standard aromatic hydrocarbon-catalyst precursor. The in-situ growth of carbon nanotubes (CNTs) was explored as their thermal stability and effectiveness in improving performance has been previously demonstrated when used as a resin additive.
The specimens were examined with SEM, EDS, and TGA to determine the effects of both pyrolysis and CNT growth during pyrolysis of the basalt phenolic composites. These tests would confirm the presence of CNTs/CNFs directly grown in the composite by pyrolysis, and confirm their composition by EDS and Raman spectroscopy. EDS would additionally confirm that the surface of the basalt fibers possess a composition suitable for CNT growth, similar to the parameters of CVD processing. Additional testing would also show that the growth behavior of the CNTs/CNFs is dependent on temperature as opposed to composition, indicating that there is a threshold temperature necessary to facilitate the availability of catalysts from within the basalt fibers. The thermal stability shown by TGA indicates that the process of pyrolysis leaves the newly formed composite with a high degree of thermal stability, making the new materials potentially usable in applications such as turbines, in addition to large-scale thermal protection systems.M.S.M.S.E.
Masters
Materials Science Engineering
Engineering and Computer Science
Materials Science and Engineering
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Adhikari, Sudeep. "Mechanical and Structural Characterization of Mini-Bar Reinforced Concrete Beams." University of Akron / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=akron1386682169.
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Hughes, John Mark. "On the mechanical properties of bast fibre reinforced thermosetting polymer matrix composites." Thesis, Bangor University, 2000. https://research.bangor.ac.uk/portal/en/theses/on-the-mechanical-properties-of-bast-fibre-reinforced-thermosetting-polymer-matrix-composites(0fdca4e4-8d50-4a16-afd0-37d78cfb8a64).html.
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Bast fibre reinforced, unsaturated polyester matrix composites were fabricated using non-woven mats of hemp or jute fibre as reinforcement. Composites were also prepared using chopped strand mat glass fibre as reinforcement. The short-term mechanical properties of the laminates were assessed. It was observed that at equivalent fibre volume fractions the stiffness of the glass fibre reinforced material only marginally exceeded that of the two, unmodified bast fibre, reinforced materials. At equivalent fibre volume fractions, however, the strength of the glass fibre reinforced composite was found to be significantly greater than that of the bast fibre reinforced materials. It was noted that in the bast fibre reinforced composites, the onset of non-linear behaviour occurred at relatively low applied stresses. Work of fracture in static three-point flexure and Charpy impact strength tests, indicated that the toughness of the plant fibre reinforced material was as much as an order of magnitude less than that of the glass fibre reinforced material. Fracture mechanics techniques were used to further quantify toughness and confirmed this to be so. Furthermore, these tests indicated that the microstructure of the bast fibre reinforced material should be examined more closely. Microscopy conducted on the fibres revealed that these were often subject to extensive micro-compressive damage. It was postulated that uneven fibre straining characteristics could lead to compromised interfacial properties, which might in turn detrimentally affect the macroscopic behaviour of the composite. A technique known as half fringe photoelasticity was used to investigate the stress-field in the matrix surrounding the fibre defects. It was observed that not only did concentrations of stress occur in the vicinity of these, but also that the shear stress distribution along the length of the fibre was interrupted by the presence of the defects. The implications of fibre defects upon composite properties are discussed.
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Vio, Lagos Cristóbal Tomás. "Interferómetro Infrarrojo Heterodino de Bajo Costo Basado en Fibra ptica para la astronomía: primeras instalaciones y pruebas en el laboratorio." Tesis, Universidad de Chile, 2012. http://www.repositorio.uchile.cl/handle/2250/104378.
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El presente trabajo de título se enmarca en el proyecto “Estudio de factibilidad experimental de la interferometría heterodina infrarroja basada en fibra en Chile” y su objetivo es el acondicionamiento del primer experimento de interferencia infrarroja con fibra óptica del mismo. Se busca observar el comportamiento de fase de las señales en la banda de frecuencia intermedia de 50 MHz.
Se monta el experimento de interferencia y se registra mediciones de diferencia de fase, constatando la factibilidad de la medición del beat optico por medio de fotodiodos, la estabilidad de fase del sistema y la dependencia de las mediciones con las variaciones del largo óptico recorrido por cada señal, corroborando así el principio fundamental de la interferometría heterodina basada en fibra optica.
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Hoto, Rene. "Fabricación mediante procesos de transferencia de resina y caracterización mecánica de materiales compuestos a partir de matrices poliméricas reforzadas con fibra de basalto." Doctoral thesis, Universitat Politècnica de València, 2015. http://hdl.handle.net/10251/53932.
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[EN] In this work, first, it has been conducted a study on the experimental determination of the permeability of a fibrous reinforcement. To reach this end, a test bench have been designed and mounted. After calibration and preliminary tests, the test bench has been used within the framework of a concurrent measurement exercise, namely "Permeability Benchmark II", in which has taken part a dozen research centers worldwide. The results obtained are analyzed in order to determine the different factors that cause dispersions during experimental determination of permeability values.
Moreover, it has been studied the impact behavior of a composite material from a matrix fiber reinforced polybutylene terephthalate basalt. The work has focused on two main points. First, the manufacturing process via vacuum-assisted resin transfer molding. Subsequently it has been performed some physical characterizations to determine some properties as crucial as the density, crystallinity, void content and fiber properties. In order to make a robust interpretation of the response to impacts of rolling, besides the actual impact characterization, the interlaminar strength characterization has been considered. The range of incident energy ranges from very low levels to achieve energy penetration. For obvious reasons, it has been conducted a duplicate study on a equivalent material made of a commercial epoxy matrix reinforced with the same fabric.
Due to environmental concerns, it is important to find an alternative to traditional materials used for the manufacture of composite materials. In this work, it has been conducted a study on the manufacturing and mechanical characterization of an asymmetric sandwich laminate from a bio-reinforced epoxy and flax and basalt matrix, being the core of natural cork. The dynamics of water absorption and the flexural behavior have been e experimentally estimated. Modifying the initial parameters allows influencing the infiltration of the resin through the pores of the cork thus changing the local stiffness and therefore the behavior of the material.[ES] En este trabajo, en primer lugar, se ha llevado a cabo un estudio sobre la determinación experimental de la permeabilidad de un refuerzo fibroso. Para llegar a tal fin, se ha concebido y fabricado un banco de ensayo. Después de su calibración y ensayos preliminares, se realizaron unos ensayos dentro del marco de un ejercicio de medición concurrente Permeability Benchmark II, que re'une una docena de laboratorios a nivel internacional. Los resultados obtenidos se analizan con el objetivo de determinar los diferentes factores que provocan dispersiones en los resultados recolectados. Por otra parte, se ha estudiado el comportamiento a impacto de un material compuesto a partir de una matriz de polibutilén tereftalato reforzada con fibra de basalto. El trabajo se ha centrado en dos puntos principales. En primer lugar, la fabricación vía moldeo por transferencia de resina asistida por vacío. Posteriormente se ha realizado una caracterización física para determinar algunas propiedades tan determinantes como la densidad, la cristalinidad, el contenido de vacíos y de fibras. Teniendo en cuenta que para poder realizar una sólida interpretación de la respuesta frente a impactos de los laminados, además de la caracterización a impacto propiamente dicha, se ha estudiado la resistencia interlaminar. El rango de energía incidente cubre desde niveles muy bajos hasta alcanzar la energía de penetración. Cabe destacar que por motivos obvios, se ha realizado un estudio paralelo sobre una matriz epoxi reforzada con el mismo tejido. Actualmente, por razones relacionadas con el medioambiente, es importante buscar algunas alternativas a los materiales tradicionales utilizados para la fabricación de materiales compuestos. En este trabajo se ha realizado un estudio sobre la fabricación y la caracterización mecánica de un material tipo sándwich asimétrico a partir de una matriz bio-epoxi y refuerzos de lino y basalto, siendo el n'ucleo de corcho natural. Se ha estudiado la dinámica de absorción de agua y el comportamiento a flexión. Modificando los parámetros iniciales de ha podido influenciar la infiltración de la resina a través de los poros del corcho lo que modifica la rigidez local y por lo tanto el comportamiento del material.
[CAT] En este treball, en primer lloc, s'ha dut a terme un estudi sobre la determinació experimental de la permeabilitat d'un reforç fibrós. Per a arribar a aquest fi, s'ha concebut i fabricat un banc d'assaig. Després del seu calibratge i assajos preliminars es van realitzar uns assajos dins del marc d\'un exercici de mesurament concurrent Permeability Benchmark II, que reunix una dotzena de laboratoris a nivell internacional. Els resultats obtinguts s'analitzen amb l'objectiu de determinar els diferents factors que provoquen dispersions en els resultats recol·lectats. Per altra banda, s'ha utilitzat el comportament a impacte d'}un material compost a partir d\t'una matriu de polibutén tereftalato reforçada amb fibra de basalt. El treball s'}ha centrat en dos punts principals. En primer lloc, la fabricació via model per transferència de resina assistida per buit. Posteriorment s'ha realitzat una caracterització física per determinar algunes propietats tan determinants com la densitat, la cristal·linitat, el contingut de buits i de fibres. Tenint en compte que per a poder realitzar una sòlida interpretació de la resposta enfront d'impacte dels laminats, a més de la caracterització a impacte pròpiament dita, s'ha estudiat la resistència interlaminar. El rang d'energia incident cobreix des de nivells molt baixos fins a aconseguir l'energia de penetració. Cal destacar que per motius obvis, s'ha realitzat un estudi paral·lel sobre una matriu epoxi reforçada amb el mateix teixit. Actualment, per raons relacionades amb el medi ambient, és important buscar algunes alternatives als materials tradicionals utilitzats per a la fabricació de materials compostos. En este treball s'ha realitzat un estudi sobre la fabricació i la caracterització mecànica d'un material tipus sandvitx asimètric a partir d'una matriu bio-epoxi i reforços de lli i basalt, sent el nucli de suro natural. S'ha estudiat la dinàmica d'absorció d'aigua i el comportament a flexió. Modificant els paràmetres inicials s'ha pogut influenciar la infiltració de la resina a través dels porus del suro, el que modifica la rigidesa local i per tant el comportament del material.
Hoto, R. (2015). Fabricación mediante procesos de transferencia de resina y caracterización mecánica de materiales compuestos a partir de matrices poliméricas reforzadas con fibra de basalto [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/53932
TESIS
43
Lee, Rebecca Irene. "Dendrochronological Methods to Examine Plant Competition with Changing Fire Regimes in Desert and Forest Ecosystems." BYU ScholarsArchive, 2019. https://scholarsarchive.byu.edu/etd/8708.
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Human activities are changing wildfire regimes globally through ignition, spread of invasive species, fire suppression, and climate change. Because of this, ecosystems are experiencing novel fire regimes that may alter plant growth and patterns of succession. Annual growth rings are one metric that can track changes in tree and shrub growth patterns over time in response to changing fire frequency. In Chapter 1 we explored the effects of fire on resprouting native shrubs in the Mojave Desert. Fires are becoming increasingly frequent due to the spread of highly flammable invasive grasses in the region. We monitored growth and fruit production of Larrea tridentata D.C. (creosote bush) on burned and unburned transects from three independent 2005 wildfires. Even though creosote has a high fire mortality rate, we found that resprouting creosote produced 4.7 times the amount of fruit and had stems that grew nearly twice as fast compared to creosote in unburned areas. Our data suggest that creosote can resprout after fire and thrives in its growth rates and reproduction in post-fire environments. In Chapter 2 we used annual Basal Area Increment to investigate how fire suppression has altered facilitation and competition interactions through stages of succession in mixed aspen-conifer forests. We found that aspen had lower growth rates in mixed aspen-conifer stands compared to aspen dominant stands. We also found that aspen growing with an associated fir tree due to facilitation had increasingly lower growth rates over time than those growing independently. Fir trees in mixed stands were facilitated over time by associated aspen trees while fir trees growing in association and independently in aspen stands showed no statistical difference from each other but grew better than independent fir trees in mixed stands. Our data suggest that restoring a more frequent fire regime will balance competitive interactions between aspen and conifer in subalpine forests.
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Castro, Mandujano Rolando Carlos. "Diseño de una red FTTH basado en el estándar GPON para la conexión de videocámaras para el distrito de San Martin de Porres." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2019. http://hdl.handle.net/10757/625704.
Full textAbstract:
Los sistemas de transmisión de datos basados en fibra óptica se han constituido en el medio de comunicación más admisible para la transmisión de video, audio, voz y datos; especialmente para comunicaciones de alta velocidad.
En el presente proyecto de tesis se busca diseñar una red FTTH basado en el estándar GPON para la conexión de videocámaras para el distrito de San Martin de Porres, dada la necesidad de tener una arquitectura de red de fibra óptica; además, de contar con un medio de transmisión confiable para las videocámaras a desplegarse en el distrito.
Uno de los grandes problemas de la arquitectura actual de comunicaciones inalámbrica es la falta de capacidad, crecimiento y disponibilidad de ancho de banda para poder operar correctamente con sus sistemas de seguridad ciudadana. Así, el Plan Local de Seguridad Ciudadana 2017 – 2018 del distrito es el documento en el cual se basa este proyecto, a fin de recopilar información y determinar las ubicaciones críticas que necesitan ser cubiertas por videocámaras de seguridad.
Este proyecto se enmarca en las mejoras a las arquitecturas de red de tipo MAN como es el estándar GPON de tipo FTTH (Fibra hasta el hogar) que es capaz de cubrir grandes distancias sin necesidad de usar repetidores de señal y/o amplificadores, y que además de eso, ofrece un ancho de banda de transmisión de gran envergadura, que proporciona confiabilidad para la transmisión y procesamiento de información que generen las videocámaras de seguridad. Asimismo, cabe mencionar que actualmente, dicho estándar viene siendo implementado por operadores de telecomunicaciones que brindan servicios a través de un solo medio de trasmisión que les ofrezca un ancho de banda.The fiber-optic data transmission systems have become the most admissible means of communication for the transmission of video, audio, voice and data; especially for high-speed communications. In this thesis project we are looking to design an FTTH network based on the GPON standard for the connection of video cameras for the district of San Martin de Porres, given the need to have an optical fiber network architecture; in addition, to have a reliable transmission medium for the camcorders to be deployed in the district. One of the great problems of the current architecture of wireless communications is the lack of capacity, growth and availability of bandwidth to be able to operate correctly with its citizen security systems. Thus, the Local Civic Security Plan 2017 - 2018 of the district is the document on which this project is based, in order to gather information and determine the critical locations that need to be covered by security camcorders. This project is part of the improvements to MAN network architectures such as the GPON standard of type FTTH (Fiber to the home) that is capable of covering large distances without the need to use signal repeaters and / or amplifiers, and In addition, it offers a wide transmission bandwidth, which provides reliability for the transmission and processing of information generated by security camcorders. It should also be mentioned that currently, this standard is being implemented by telecommunications operators that provide services through a single transmission medium that offers them a bandwidth.
Tesis
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Nezzar, Hachemi. "Etude in vivo du connectome des saccades oculomotrices chez l'Homme par imagerie structurelle." Thesis, Clermont-Ferrand 1, 2016. http://www.theses.fr/2016CLF1MM15/document.
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Le système visuel humain est complexe par son organisation anatomique et par son fonctionnement incomplètement élucidé. Il est fonctionnellement divisé en deux systèmes. Le premier système est destiné à la vision consciente communément appelée voie visuelle principale ou en anglais « image forming visual pathways ». Le second, appelé système secondaire ou accessoire, n’apporte pas d’information visuelle consciente, il est dit « non image forming visual pathway ». Ce dernier apporte à notre cerveau une information sur l’environnement telle que la sensation jour/nuit. Ses fonctions sont sous-tendues par l’afflux d’informations rétiniennes non visuelles sur des structures de l’hypothalamus comme le noyau supra-chiasmatique. Les deux systèmes visuels ont un substratum anatomique complexe faisant intervenir de nombreuses structures anatomiques au sein des différents étages du cerveau cortical et sous-cortical comme les noyaux gris centraux dits « Basal Ganglias » (BG). Le système visuel secondaire intervient aussi comme une structure de contrôle des mouvements oculomoteurs tels que la poursuite ou les saccades nécessaires pour explorer notre environnement. Ainsi les saccades oculomotrices sont sous le contrôle modulateur des BG. De ce fait l’étude des saccades apparait comme un très bon modèle pour explorer le fonctionnement du système extrapyramidal au cours des maladies neuro-dégénératives. Les connaissances actuelles sur ce système de contrôle des saccades proviennent essentiellement des études sur le primate non humain et sur des observations cliniques chez l’homme au cours de pathologies dégénératives ou toxiques des BG. L’observation des structures anatomiques, en particulier du réseau de la substance blanche cérébrale qui supporte les connections axonales, n’est pas accessible à l’imagerie clinique de routine. Pour décrire et étudier ces réseaux de connections, la notion de connectomique a été introduite il y a un dizaine d’années. Dans ce travail, nous nous sommes donné l’objectif de décrire le connectome des saccades oculomotrices sur un plan structurel. Nous avons exploré les structures sous-corticales intervenant dans le contrôle des saccades comme les BG, le colliculus supérieur et le pulvinar. Pour ce faire, nous avons utilisé l’imagerie IRM structurelle en diffuseur de tension (DTI) chez deux groupes de patients présentant une maladie neuro-dégénérative : un groupe souffrant de maladie de Parkinson chez qui une atteinte des BG et une dysfonction des saccades sont reconnues, et un groupe de trembleurs essentiels reconnu pour ne pas présenter de dysfonction des saccades et chez qui les BG sont épargnés. Le résultat de ce travail a permis pour la première fois une description in vivo du connectome des saccades chez l’Homme. Il a de plus montré des différences dans la structure du connectome dans les deux groupes de patients. Une meilleure connaissance de ce connectome pourrait permettre de mieux comprendre certains troubles oculomoteurs et aussi de suivre l’évolution de certaines maladies neurodegenerativesVisual system is complex by its anatomy and its function. Neuro-anatomists have been interested in understanding the link between the visual pathways and the brain for centuries. Classical brain fixation and dissection methods were used to describe the visual pathways identifiable macroscopically. Non–image visual pathway, particularly the part involves in saccadic eye movements network in human is still not mastered. Our current knowledge in SCM is based on animal studies, anatomic dissection and brain histopathology examination of specimens from patients with clinical basal ganglia (BG) disorders. Saccadic eye movements (SCM) are under the control of the basal ganglia (BG) and SCM circuitry within the BG represents a good model for studying pathology in the extra-pyramidal system. The diagnosis of Parkinson’s disease (PD), which affects SEM and its distinction from non-dopaminergic, essential tremor (ET) where SEM are not impaired can be challenging and still relies on clinical observations. Diffusion tensor imaging and fiber tractography (DTI-FT), a new MRI technology, can be used to evaluate the presence and integrity of white matter tracts using directional diffusion patterns of water. The purpose of this study is to use DTI-FT to analyse SEM networks within BG and compare the SEM neural pathways or connectome of patients clinically diagnosed with PD and ET. To date, there are no studies, using DTI-FT for the extensive exploration of non-image visual pathways and SCM circuits, notably the deep brain connections. For this goal, we introduced the concept of SCM connectomes, derived from the general concept of connectome. Our study used structural MRI to identify nuclei and fascicles of the SCM connectome in PD and ET patients; imageries were acquired in routine clinical conditions fitted for DBS surgery. We found a reduction of the fiber number in two fascicles of the connectome in PDcompared to ET group
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Tillová, Jana. "Studium chování betonů při působení vysokých teplot." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-225881.
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This master‘s thesis is focused on the study of the behavior of cement concrete at high temperatures with a focus on monitoring the impact of aggregate and cement type. This work describes the processes in aggregates and cement matrix at high temperatures. The theoretical part describes the selestion of a suitable aggregate and cement for the surroundings with potential exposure to high temperatures. In the experimental part is given design of composition of a concrete with two types of aggregates and four cements. It has been suggested 8 recipes. Changes were observed densities, compressive strength and tensile strength in bending, calculate the velocity of propagation of waves with ultrasonic pulsed method. Also evaluated the appearance of the surface samples after thermal load – cracks on the surface and measure the maximum crack width.
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Mikulinec, David. "Betony s vyšší odolností vůči působení vysokých teplot." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2012. http://www.nusl.cz/ntk/nusl-225537.
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The result of this master’s thesis is acquaintance with the issues of cement concrete resistance to high temperatures. This work describes the processes ongoing in the structure of concrete at extreme thermal loads and analysis of effects of high temperatures on the individual components of reinforced concrete structures is given, then influence of high temperatures and fire on the aggregates, matrix, reinforcement steel and the resulting changes in their properties. In the experimental part is given design of composition of concrete with a higher resistance to high temperatures and subsequent verification of the physico-mechanical properties of sample of concrete after exposure to temperatures at intervals of 200 ° C, 400 ° C, 600 ° C and 900 ° C. In individual recipes were observed changes of volume weight, changes of compressive strength and tensile strength flexural , tensile strength of surface layers and the occurrence of cracks and then were compared the results of thermally loaded and unloaded samples. The benefit in this issue is to evaluate the surface appearance of samples after heat load - study of area of crack and measurement of their width - was used according to the methodology's authors Xing, Hebert, Noumowe a Ledesert given in Cement and Concrete Research. This methodology allows to quantify changes of surface, after temperature load.
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ORSINI, ENRICO. "Filtri ottici integrati basati su reticoli di Bragg realizzati su materiale ibrido Sol-Gel." Doctoral thesis, Università degli Studi di Roma "Tor Vergata", 2010. http://hdl.handle.net/2108/1213.
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Oggi i sistemi di telecomunicazione sono basati sulla trasmissione di segnali luminosi in fibra ottica e il loro sviluppo viene a dipendere dalla capacità di trasdurre, rivelare e controllare il segnale ottico trasmesso nella fibra. La branca della fisica da cui dipende il progresso delle telecomunicazioni in fibra ottica è la fotonica integrata, cioè la fabbricazione e l’integrazione su un comune substrato di componenti ottici capaci di filtrare, modulare e rivelare il segnale ottico. Nell’ultimo decennio, gli ambienti di ricerca in questo campo, si sono interessati alla sintesi di materiali innovativi e allo sviluppo di tecniche d fabbricazione altrettanto innovative, con lo scopo di produrre dispositivi ottici integrati a basso costo e con processi relativamente semplici. In questo lavoro, tale obiettivo è stato raggiunto fabbricando un filtro ottico integrato a reticoli di Bragg (implementazione dei reticoli di Bragg sopra la guida d’onda canale) su materiale ibrido organico/inorganico a base di Titanio, sintetizzato mediante il processo Sol-Gel. Su questo materiale, l’opportuna illuminazione del sistema con radiazione ultravioletta permette la realizzazione di strutture come guide d’onda canale e reticoli di Bragg, elementi ottici alla base della struttura del filtro. Questo dispositivo è stato progettato con lo scopo di filtrare nella terza finestra ottica delle telecomunicazioni a 1550 nm, in modo da ridurre i problemi legati alla dispersione del segnale nella fibra ottica. Per la fabbricazione del filtro, si sono usate la fotolitografia UV per la realizzazione delle guide d’onda canale e la litografia interferenziale laser per la realizzazione dei reticoli di Bragg. Le guide d’onda canale hanno mostrato bassi valori di attenuazione e i reticoli di Bragg una buona uniformità. In questo caso, è stata applicata la tecnica della Soft-Lithography, cioè tali strutture (reticoli) sono state usate come master per produrre uno stampo siliconico (Mold di polidimetilsilossano) per replica-molding. Con tale stampo, le strutture sono state replicate in serie su nuovi film (sempre matrici Ti/TMSPM con Irgacure 184) per ”UV-nanoimprinting”. Il processo ha permesso di ottenere una replica fedele dei reticoli di Bragg presenti sul master ed è stato quindi usato anche nella replica di tutto il dispositivo di filtro ottico. Il master del filtro ottico da cui realizzare il mold di PDMS, è stato sviluppato con un processo in cui sono state combinate le tecniche di “Electron-Beam-Lithography”, fotolitografia UV e “Reactive-Ion-Etching”. Tale processo ha permesso di fabbricare selettivamente i reticoli di Bragg sulla sommità della guida d’onda canale, condizione necessaria per avere un filtro con elevate prestazioni ottiche. La qualità del master del filtro ottico è stata valutata attraverso la misura dell’efficienza di attenuazione, pari a -10 db alla lunghezza d’onda di 1547 nm. Da questo master è stata ottenuta la replica fedele e in serie del filtro ottico. In conclusione, questo dimostra che con la tecnica della Soft-Lithography , abbiamo ottenuto un processo semplice ed economico, quindi industrialmente vantaggioso, per fabbricare nanostrutture su matrici ibride Sol-Gel.Bragg gratings optical filters can be considered one of the key elements in many integrated optical devices such as wavelength-division multiplexing (WDM), optical fibre sensors, gain-flattening filters and add-drop multiplexers (OADM’s), optical couplers, resonators and modulators. Over the past decade, extensive research has been conducted in order to improve the unconventional fabrication techniques to obtain low-cost optical devices. Several Bragg gratings-based optical devices have been obtained by merging conventional and unconventional fabrication techniques. In my Phd, the device consists of a hybrid titanium (organic/inorganic Sol-Gel material) optical filter for the third’s telecommunication optical windows (1550 nm) based on Bragg gratings loaded channel waveguide. The fabrication of the device is obtained by merging conventional and unconventional technique. The unconventional fabrication technique is the Soft-Litography, a very innovative process based on Replica-molding and UV-nanoimprinting for micro- and nano- fabrication. This process is characterized by low cost and fast processing using relatively inexpensive tools. Starting from sub-micrometric gratings (master) fabricated on Silicon wafer by means of standard Electron Beam Lithography (EBL) a soft mold (stamp) has been produced by replica-molding. Using the stamp, the initial master structures (Bragg gratings) were replicated onto sol-gel photosensitive films by Uv-nanoimprinting. The resulting films underwent a further photolithographic step combined with Reactive Ion Etching (RIE), thus producing a channel waveguide with Bragg gratings on the top. This wavelength filter have been optically characterized by transmission measurements in the range 1450 nm – 1590 nm by a tuneable IR diode laser. The efficiency was about -10 dB and the bandwidth at Full Width Half Maximum (FWHM) 1,7 nm. So, Titanium based wavelength filters, obtained by the merging of conventional photolithography and Soft-Lithography, have been demonstrated. The use of sol-gel technology with S-L methods makes thus possible to produce passive optical devices starting from a hard silicon master. Furthermore, thanks to high versatility of S-L process, a consistent replica of the master optical filter (i.e. channel with Bragg gratings) allows to replicate the pattern (at the nanometric scale) directly on a new sol-gel planar film. The morphological characterization by Atomic force microscopy of the replicated structure (optical filter), shows a good agreement with the Master. In conclusion, this means that we have obtained a simple process, low cost and industrially advantageous, to fabricate nanostructures on Sol-Gel matrix.
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Chang, Cabanillas Víctor Manuel. "Diseño e implementación de un sistema de detección, localización y alerta de averías en redes de fibra óptica de planta externa metropolitana basado en información georeferenciada." Bachelor's thesis, Pontificia Universidad Católica del Perú, 2014. http://tesis.pucp.edu.pe/repositorio/handle/123456789/6075.
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En la presente tesis se presenta el diseño e implementación de un sistema que contribuya a agilizar los tiempos de atención de averías en enlaces de fibra óptica de una red planta externa metropolitana. Con este fin, se plantea un sistema centralizado de detección, localización y alerta de averías, el cual involucra el uso de tecnologías flexibles para visualizar y gestionar a los elementos de la red, los clientes y el despliegue de los cables de fibra óptica, así como el uso de información georeferenciada de la red para facilitar el monitoreo de la misma.
Esta tesis se estructura de la siguiente forma:
En el capítulo 1 se detalla el escenario actual del monitoreo de una red de planta externa metropolitana, se determina la problemática y los objetivos del proyecto.
En el capítulo 2 se desarrolla el marco teórico de las metodologías de detección y localización de averías en redes de fibra óptica. Se analizan las principales soluciones de monitoreo utilizadas actualmente y luego se elige la que aborda mejor la problemática y los requerimientos clave, para después plantear el modelo teórico del sistema.
En el capítulo 3 se presenta el diseño e implementación del sistema en cuestión, a través de diagramas de clase, la arquitectura del sistema y el detalle de cada funcionalidad implementada.
Finalmente, en el capítulo 4 se muestran las interfaces del prototipo implementado y las pruebas realizadas a cada funcionalidad, Así como el detalle de los resultados obtenidos.Tesis
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Novotný, David. "Vliv anorganických vláken na fyzikálně mechanické vlastnosti cihlářského střepu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2017. http://www.nusl.cz/ntk/nusl-265311.
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This diploma thesis will discuss possibilities of using inorganic fibers to improve the mechanical properties of the resulting physical body bricks. Assessment of the effect of fiber length, fiber thickness is in the order of micrometers. In this work we were used fibers which are commercially produced for the purpose of reinforcement, but also waste fibers, which mainly serves as an insulator.