Literatura académica sobre el tema "Production des fibres de lin"
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Artículos de revistas sobre el tema "Production des fibres de lin"
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CHILLIARD, Y., A. FERLAY y M. DOREAU. "Contrôle de la qualité nutritionnelle des matières grasses du lait par l’alimentation des vaches laitières : acides gras trans, polyinsaturés, acide linoléique conjugué". INRAE Productions Animales 14, n.º 5 (17 de diciembre de 2001): 323–35. http://dx.doi.org/10.20870/productions-animales.2001.14.5.3758.
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Après un rappel des voies métaboliques et des flux de nutriments qui concourent à la lipogenèse mammaire, cet article est consacré aux principaux effets de l’alimentation sur la composition en acides gras (AG) du lait de ruminant, en particulier les AG polyinsaturés, les AG monoinsaturés trans et l’acide linoléique conjugué (CLA). Les principaux facteurs alimentaires étudiés sont la nature des fourrages (dont l’herbe pâturée), le suif, protégé ou non, et la supplémentation des rations avec des huiles végétales ou marines (poisson ou algues), protégées ou non. La supplémentation en suif augmente la sécrétion d’acide oléique. La teneur du lait en C18:2 est comprise entre 2 et 3 % avec les rations non supplémentées en lipides, elle n’est augmentée que de 1,5 point lors d’un apport de graines ou d’huiles riches en C18:2, en raison d’une hydrogénation ruminale poussée. Les rations à base d’herbe (riches en C18:3) augmentent légèrement (0,5 à 1 point) la proportion de C18:3 dans le lait par rapport aux rations à base d’ensilage de maïs. La graine de lin permet un accroissement d’environ 0,3 point. La teneur en C20:5 (EPA) et en C22:6 (DHA) est accrue jusqu’à 0,5 % des AG totaux par l’addition d’huiles marines à la ration. Le taux butyreux du lait peut être fortement diminué par les régimes pauvres en fibres et riches en céréales et/ou par l’administration d’huiles marines ou végétales riches en AG insaturés. Les C18:1 trans, notamment les C18:1 trans 11 et trans 10, mais aussi le trans 10, cis 12 CLA, pourraient jouer un rôle dans cette diminution en inhibant la lipogenèse mammaire. Les régimes alimentaires augmentant les proportions des CLA et des C18:1 trans dans le lait sont ceux qui apportent des précurseurs lipidiques pour la formation de ces AG, ou qui modifient l’activité microbienne associée à l’hydrogénation ruminale des AG polyinsaturés ou l’activité de la désaturase mammaire. L’influence de l’alimentation sur les différents isomères du C18:1 et du CLA du lait a été peu étudiée.
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Okine, E. K., G. W. Mathison y R. T. Hardin. "Relations between passage rates of rumen fluid and particulate matter and foam production in rumen contents of cattle fed on different diets ad lib." British Journal of Nutrition 61, n.º 2 (marzo de 1989): 387–95. http://dx.doi.org/10.1079/bjn19890125.
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1. A group of six cattle, three of which had a non-bloating history (group A) and had been ruminally cannulated for the previous 2 years, and three with a history of being bloat-prone (group B) and which had been ruminally cannulated only 3 months before the study, were fed ad lib. on chopped lucerne (Medicago sotiva) hay, lucerne pellets, or a 100 g chopped hay and 900 g rolled barley grain/kg diet over three periods of 30 d each. Flow of rumen digesta, by reference to CoEDTA and chromium-mordanted fibres, and foam production from samples of rumen contents were measured.2. Samples of rumen contents (50 ml) from group A produced foam heights of 150 and 60 mm, 2 and 4 h after feeding respectively, compared with 240 and 150 mm for group B (P < 0.05).3. The fractional passage rate of the 1-2 mm particles mordanted with Cr did not differ (P > 0.05) between groups.4. The fractional outflow rates (FOR) for CoEDTA 0-2 h and 2-7 h after feed was offered were 0.205 and 0.160/h for group A and 0.093 and 0.086/h for group B respectively (P < 0.05).5. Rumen-fluid FOR 0-2 h and 2-7 h after provision of feed were significantly (P < 0.05) inversely correlated (r -0.74 and -0.85 respectively) with the amount of foam produced from rumen contents at these times.
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Paranagama, Iranga, Indira Wickramasinghe, Dulani Somendrika y Kasun Benaragama. "DEVELOPMENT OF A VEGAN SAUSAGE WITH YOUNG GREEN JACKFRUIT, OYSTER MUSHROOM, AND COCONUT FLOUR AS AN ENVIRONMENTALLY FRIENDLY PRODUCT WITH CLEANER PRODUCTION APPROACH". Journal of microbiology, biotechnology and food sciences 11, n.º 4 (1 de febrero de 2022): e4029. http://dx.doi.org/10.55251/jmbfs.4029.
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Veganism or vegetarianism is a trending topic in the modern world. Natural disasters, climate change, and pandemics lead people towards healthier and plant-based diets and nature-friendly lifestyle. Higher meat consumption has led the world into a huge struggle resulting in global warming, rising sea levels, disease spreading like swine flu, bird flu, coronavirus, etc. The main objective of this research was to develop a socially responsible vegan product, minimizing its environmental impact with a cleaner production approach. Generally, many vegan products are produced using soy as the main ingredient, but it is the second-largest agricultural driver of deforestation globally. Currently, there are no significant studies done on vegan product development considering the environmental impact and cleaner production. Concerning all these objectives, this vegan sausage was developed with young green jackfruit (Artocarpus heterophyllus), oyster mushrooms (Pleurotus ostreatus), and coconut flour (Cocos nucifera Lin.) as main ingredients. This product was subjected to sensory evaluation, proximate analysis using AOAC and SLS methods, and microbiological analysis. The moisture, ash, total fat, crude protein, and crude fibre contents of the product were 64.49 ± 0.16%, 2.62 ± 0.18%, 5.94 ± 0.25%, 3.95 ± 0.30% and 1.22 ± 0.16% respectively. Total carbohydrate value and energy profiles were 21.78 ± 0.38% and 156.3 kcal/100 g calculated according to the Codex Guideline on Nutrition Labelling. Following a cleaner production approach helped to identify that it is more environmentally friendly using electricity than LPG in Sri Lanka for this kind of product development and to reduce the total CO2 emission per kg of vegan sausage from 0.678 kg CO2/kg to 0.477 kg CO2/kg.
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Thuault, A., S. Eve, J. Bazin, K. Charlet, F. Destaing, M. Gomina y J. Bréard. "Morphologie, biocomposition et comportement mécanique des fibres de lin". Matériaux & Techniques 99, n.º 3 (2011): 275–80. http://dx.doi.org/10.1051/mattech/2011011.
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Riedt, Tamara, Steven Goossens, Ines Gütgemann, Carmen Carrillo-Garcia, Hichem D. Gallala, Holger Fröhlich, Peter Brossart, Dany Huylebroeck, Jody J. Haigh y Viktor Janzen. "Zeb2-Defficiency in the Adult Murine Hematopoietic Precursor Cells Leads to Differentiation Defects in Multiple Hematopoietic Lineages and a Myeloproliferative-Like Phenotype". Blood 120, n.º 21 (16 de noviembre de 2012): 1199. http://dx.doi.org/10.1182/blood.v120.21.1199.1199.
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Abstract Abstract 1199 The life long replenishment of highly specialized blood cells by a small number of hematopoietic cells (HSC) requires a strict regulation between self-renewal and differentiation in the immature compartment of the bone marrow. Perturbation of this equilibrium can result in stem cell loss or hematologic malignancies. This balance is at least in part controlled by a network of transcription factors. Zeb2 is a transcriptional repressor and plays an important role during the embryonic development as a modulator of the epithelial to mesenchymal transition (EMT) as well as tumor progression and metastasis. We have previously identified the essential role of Zeb2 in murine embryonic hematopoiesis, where selective Zeb2 deficiency in the hematopoietic stem cells resulted in early lethality around day 12.5. The aim of this study was to analyze whether Zeb2 plays a specific role in the regulation of homeostasis in the adult hematopoietic system. Using the Mx1-Cre based inducible Zeb2 conditional knock out mouse model we analyzed the impact of Zeb2 loss on adult hematopoietic stem cell function. Upon the induction of Zeb2 deletion we found a significant decrease in most cell lineages of the peripheral blood, except the neutrophil granulocytes. However, the reduction of mature cells in the blood was not accompanied by reduced bone marrow cellularity, as the cellularity was similar between Zeb2Δ/Δ Mx1-Cre (Zeb2 conditional KO) mice and the control animals (Zeb2+/+Mx1-Cre). However, in the bone marrow of the Zeb2Δ/Δ Mx1-Cre animals the granulocytic lineage was dominating, whereas other lineages e.g. red blood cell precursors and B-lymphoid precursors were drastically reduced. Histological sections of the bone marrow cavity revealed megacaryocytes with abnormal morphology reflecting maturation defects and an increased production of reticular fibers in the BM of Zeb2Δ/Δ Mx1-Cre mice. In addition Zeb2Δ/Δ Mx1-Cre mice displayed a two to three fold increase in spleen size compared to control animals due to an extramedullary hematopoiesis. Analysis of the primitive hematopoietic compartment in the bone marrow and spleens revealed that Zeb2 deletion resulted in a pronounced increase in the most immature hematopoietic cells, defined as Lin-Sca1+cKit+CD48-CD150+ population, and perturbation in different lineage restricted progenitor subpopulations. No difference in cell cycling or apoptotic rate in the stem cell enriched bone marrow population (Lin-Sca1+cKit+CD48-CD150+) was detectable between the genotypes. Upon transplantation into lethally irradiated wild type recipients, Zeb2 deficient stem cells demonstrated significantly reduced ability to differentiate into multiple hematopoietic lineages indicating a niche independent effect of Zeb2 in promoting differentiation of hematopoietic stem cells. On the molecular level, gene expression analysis of hematopoietic stem and progenitor cells using microarray approach revealed increased transcripts of downstream targets of Wnt/ß-Catenin signaling, suggesting increased Wnt signaling activity in absence of Zeb2 in the hematopoietic compartment, which at least in part might be responsible for the observed phenotype. These data indicate that Zeb2 is involved in the regulation of the balance between self-renewal and differentiation at multiple stages of hematopoietic cell maturation. Furthermore the lack of Zeb2 in the hematopoietic compartment leads to a phenotype that resembles the features of human myeloproliferative disorders, especially the early stages of primary myelofibrosis with dominant granulopoiesis, production of reticular fibers in the bone marrow, and morphological abnormalities in megacaryocytes, accompanied by extramedullary hematopoiesis. Disclosures: No relevant conflicts of interest to declare.
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LANGFELD, KAREN S., JOHN D. ALTRINGHAM y IAN A. JOHNSTON. "Temperature and the Force-Velocity Relationship of Live Muscle Fibres from the Teleost Myoxocephalus Scorpius". Journal of Experimental Biology 144, n.º 1 (1 de julio de 1989): 437–48. http://dx.doi.org/10.1242/jeb.144.1.437.
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Small bundles of fast fibres were isolated from the myotomal muscle of the teleost Myoxocephalus scorpius. The temperature-dependence of isometric contractile properties and the force-velocity (P-V) relationship were studied. Fibres were found to deteriorate above 18°C, and the force plateau during tetanic stimulation was not maintained above 15°C. Twitch and tetanic tension (P0) showed optima at around 8°C. Force-velocity curves were fitted using either Hill's hyperbolic equation or a hyperbolic-linear equation (hyp-lin). The best fit to the data was provided by the hyp-lin equation, which gave consistently higher values for unloaded contraction velocity (Vmax): 4.3, 8.1 and 9.5 muscle lengths s−1 at 1, 8 and 12°C, respectively. The P-V relationship was found to become progressively more curved at higher temperatures. Muscle power output calculated from the hyp-lin equation was 123 W kg−1 at 1°C and 256 W kg−1 at 8°C. Curves normalized for P0 and Vmax at each temperature show that the change in curvature is sufficient to increase the relative power output of the muscle by around 15% on decreasing the temperature from 8 to 1°C.
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Martin, Nicolas, Peter Davies y Christophe Baley. "Influence du rouissage du lin sur les propriétés mécaniques des fibres et des composites injectés lin/polypropylène". Revue des composites et des matériaux avancés 24, n.º 1 (30 de abril de 2014): 139–53. http://dx.doi.org/10.3166/rcma.24.139-153.
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Wang Chunxia, 王春霞 y 刘云朋 Liu Yunpeng. "基于光纤传感的工业生产线智能装配系统". Infrared and Laser Engineering 51, n.º 10 (2022): 20210695. http://dx.doi.org/10.3788/irla20210695.
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Cherf, Zine Eddine, Christophe Poilane, Ladan Moyamez y Jun Chen. "Optimisation d'un préimprégné lin/époxy industriel. Influence de l'orientation des fibres". Revue des composites et des matériaux avancés 21, n.º 1 (abril de 2011): 119–28. http://dx.doi.org/10.3166/rcma.21.119-128.
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Cheour, Khouloud, Mustapha Assarar, Daniel Scida, Rezak Ayad y Xiao-Lu Gong. "Identification des coefficients d’amortissement de matériaux composites à fibres de lin". Revue des composites et des matériaux avancés 26, n.º 3-4 (30 de diciembre de 2016): 367–82. http://dx.doi.org/10.3166/rcma.26.367-382.
Texto completoTesis sobre el tema "Production des fibres de lin"
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Essid, Safa. "Sandwiches à fibres de lin et anas de lin : optimisation structure-imprégnation-propriétés". Thesis, Normandie, 2020. http://www.theses.fr/2020NORMLH05.
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Pour des raisons principalement écologiques, l’allègement des structures sandwiches et la valorisation de la biomasse lignocellulosique sont considérés comme des solutions possibles pour l’innovation durable. Dans ce contexte, les travaux de cette thèse se concentrent sur la fabrication et l’optimisation de structures sandwiches en peaux renforcées de fibres de lin avec des objectifs mécaniques, économiques et environnementaux. Une valorisation d’un sous-produit de la plante de lin que sont les anas de lin est effectuée avec le développement de panneaux agglomérés à base de ces particules. Ces panneaux serviront d’âme aux structures sandwiches. Pour arriver à l’étape d’optimisation, des caractérisations expérimentales des matériaux de matrice et d’âme sont tout d’abord effectuées. Par la suite, un travail sur le couplage entre les procédés d’élaboration et les propriétés recherchées des structures sandwiches est réalisé. L’ensemble des caractéristiques déterminées sont comparées à celles d’un matériau de référence non-biosourcé. Enfin, pour arriver à répondre à la problématique liée à l’optimisation de la conception de structures sandwiches en lin, à rigidité et à résistance à la rupture imposées, trois approches analytique, graphique et numérique sont développées. Cette procédure d’optimisation devra contrôler d’une manière systématique les caractéristiques recherchés des sandwichs en linFor different reasons including ecological ones, the weight reduction of structures and valorization of lignocellulosic biomass are considered as possible solutions towards ustainable innovation. In this context, the work of this thesis focuses on the manufacturing and optimization of sandwich structures with skins reinforced with flax fibers with mechanical, economic and environmental goals. A flax plant by-product called flax shives is valued by the development of agglomerated panels. These panels will serve as a core for the sandwich structures. To reach the optimization stage, experimental characterizations of the matrix and core materials are carried out first. Subsequently, joint work between the production processes and the desired properties of sandwich structures is undertaken. All the characteristics determined are compared with those of a non-bio-sourced reference material. Finally, analytical, graphic and numerical approaches are developed in order to answer the main question related to the optimization of the design of flax based sandwich structures with imposed rigidity and resistance to rupture. This optimization procedure should systematically control the desired characteristics of flax sandwiches
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D'ANSELME, THIERRY. "Materiaux composites renforces par des fibres vegetales en particulier par des fibres de lin". Rennes 1, 1997. http://www.theses.fr/1997REN10140.
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Ce memoire de these presente les performances des fibres vegetales comme renfort de materiaux composites a matrice organique. Plusieurs types de fibres sont analysees : le lin, le jute, la ramie et le coton. Les proprietes mecaniques des stratifies sont fonction du choix de la nature des fibres mais aussi de leur selection. Les fibres de lin font ici l'objet de travaux particuliers compte tenu de leurs proprietes et de leur disponibilite. Des fibres unidirectionnelles ou aleatoirement dispersees sont impregnees de resines thermodurcissables. Les proprietes de ces fibres, la fabrication et les performances des materiaux composites sont decrites. La faible mouillabilite des fibres par la resine et la mediocre interface fibre-matrice sont dues a la presence de groupements hydroxyles situes a la surface des fibres. Des traitements de surface sont realises pour ameliorer les proprietes mecaniques avant et apres un vieillissement. Une etude comparative est realisee entre le composite renforce par des fibres de lin et le composite renforce par des fibres de verre pour mettre en evidence l'interet des fibres vegetales dans les materiaux composites.
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Le, Hoang Tung. "Etude de caractérisation du comportement de composites cimentaires incorporant des fibres courtes de lin". Caen, 2013. http://www.theses.fr/2013CAEN2042.
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Les préoccupations économiques et environnementales liées au recyclage et aux besoins en éco-matériaux conduisent à explorer des matières premières jusque-là destinées à d’autres applications. Ceci est le cas pour le lin, matière abondante et de très bonne qualité en Normandie, Actuellement, il est surtout exporté en Chine ou en Italie, et transformé dans l’industrie textile. La valorisation de cette matière naturelle est à l’ordre du jour dans le cadre de plusieurs projets nationaux dont LINT-Lin Technique normand pour l’intégration du lin dans les matériaux composites. Dans le monde entier, un intérêt de plus en plus croissant est porté sur la fabrication des matériaux de construction incorporant des fibres végétales. Du point de vue matériau de construction, le lin est utilisé sous plusieurs formes : fibres, anas, etc. Les applications se situent principalement dans le domaine des bétons afin d’améliorer les propriétés mécaniques, thermiques et d’isolation phonique. Les matériaux incorporant des fibres végétales sont font partie de l’ensemble générique appelé agro-matériaux. L’élaboration de composites cimentaires avec des végétaux dépend d’un certain nombre de paramètres telles que les proportions du mélange, les méthodes de malaxage, de manipulation et de mise en place qui s’avèrent très influentes sur les propriétés des composites à l’état frais et à l’état durci. Ce travail, réalisé au sein du Laboratoire sur les matériaux de Construction de l’ESITC Caen et du laboratoire de Cristallographie des Matériaux (Crismat, UMR 6508) de Caen, consiste à étudier le rôle des fibres de lin sur la rhéologie des pâtes cimentaires, la microstructure des composites obtenus et leurs propriétés mécaniques. Les paramètres relatifs aux fibres sont leur morphologie (longueur), leurs caractéristiques mécaniques, leur état de surface et leur taux volumique. Le mémoire est constitué de cinq chapitres. Le premier est une étude bibliographique qui présente les caractéristiques des fibres végétales les plus usitées en éco-construction en portant une attention particulière à la fibre de lin. Les propriétés des composites cimentaires incorporant des fibres végétales sont présentées et discutées en termes de la nature et du taux des fibres ainsi que des facteurs de mise en œuvre les plus influents. La caractérisation des constituants de la matrice cimentaire et des fibres de lin est présentée dans le deuxième chapitre. La formulation et la préparation des matériaux composites cimentaires y sont décrites de façon détaillée afin de donner une vision générale sur les méthodes de mise en œuvre typiques à ces matériaux. Le troisième chapitre porte sur la caractérisation des pâtes mortier - fibres de lin à l’état frais. L’analyse de la consistance, du temps de prise et de la variation dimensionnelle a été menée dans le but de comprendre les effets de différents paramètres du mélange et de proposer une optimisation de la mise en œuvre. La caractérisation physique, mécanique et microstructurale des composites mortier - fibres de lin à l’état durci fait l’objet du quatrième chapitre. Dans le cas de la formulation béton – fibres de lin, l’étude de la consistance à l’état frais et des propriétés mécaniques à l’état durci est présentée dans le cinquième et dernier chapitre. La conclusion générale rappelle les principaux résultats de l’étude en mettant en exergue la complémentarité des différentes méthodes utilisées, et propose des voies d’investigaton pour compléter ce premier travail sur les matériaux de construction « bétons – fibres de linNowadays, a growing interest is focused on increasing the production of building materials incorporating vegetable fibers. In building material, flax is used in several forms: fibers, shives, etc. Their applications in the concrete are to improve the mechanical, thermal and sound insulation. Materials incorporating plant fibers are part of generic group called agro-materials. The production of cementitious composites with plant depends on a number of parameters such as the mixing ratios, mixing methods, manipulation techniques and mixtures which are very influential on the properties of the composites on the fresh and hardened state. This work, carried out in the Laboratory of Construction Material ESITC Caen and Laboratory of Crystallography of Materials (Crismat, UMR 6508) of Caen, involve in studying the role of flax fibers on the rheology of cement pastes, the microstructure and mechanical properties of composite. The parameters related to fibers are their morphology (length), their mechanical characteristics, their surface condition and their volume ratio. The thesis consists of five chapters. The first is a bibliographic study that present the characteristics of the most commonly used in eco-construction plant fibers with particular attention to the flax fiber. The properties of cement composites incorporating vegetable fibers are presented and discussed in terms of the nature and fiber ratio. Characterization of constituents of the cementitious matrix and fibers is presented in the second chapter. The formulation and preparation of cementitious composite materials are described in detail in order to give an overview on the methods of these materials in typical work. The third chapter focuses on the characterization of flax mortar. The analysis of consistency, setting time and dimensional variation was conducted in order to understand the effects of different mixing parameters and propose an optimization of the implementation. Physical characterization, mechanical and microstructural of flax fibers reinforced composite in the hardened state the subject of the fourth chapter. In the formulation of flax fibers reinforced concrete, the study of consistency on the fresh state and mechanical properties in the hardened state is presented in the fifth and final chapter. The conclusions recalls the main results of the study highlighting the complementarity of different methods and proposes investigation to complete the first work on building materials "flax fibers reinforced concrete. "
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Qin, Yimin. "The production of fibres from chitosan". Thesis, University of Leeds, 1990. http://etheses.whiterose.ac.uk/11299/.
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A wet spinning procedure was developed for the production of chitosan fibres. The dope was prepared by dissolving 5% w/w medium grade chitosan in 2% aqueous acetic acid; after filtration and degassing, fibres were produced by extrusion of the dope into an aqueous NaOH bath and further drawing, washing, drying and winding. The effect of changes in the spinning conditions on the properties of chitosan fibres was studied; it was found that spinning variables such as jet stretch ratio, draw ratio and coagulation bath concentration had little effect on the fibre properties, though higher draw ratios would be obtained at lower jet stretch ratios and slightly improved tenacities were obtained using more dilute NaOH solutions as the coagulant. The drying methods, however, had a big effect on the fibre properties; the fibres obtained by air drying had a much higher extensibility than those dried by radiant heating. The addition of i-propanol to the dope gave much whiter fibres while the addition of Na2S04 to the coagulation bath produced the strongest fibres. Overall, the fibres produced in this work had tenacities between 0.61 and 2.48 g/dtex and extensibilities of 5.7 to 19.3%, with individual fibre decitex ranging from 2.5 to 7.5. The fibres had round cross-sections and a smooth surface when dried with heating or a rough surface when dried with acetone. The chelating properties of the chitosan fibres were studied; it was found that upto 8% Cu(II) and 5% Zn(II) can be absorbed into the fibres within 40 minutes. The Cu(II) and Zn(II) ions had strong effects on the fibre tensile properties; both dry and wet strengths were remarkably increased with the absorption of metal ions. In addition, the fibres chelated with ZnS04 had a LOI estimated to be 52%. The chitosan fibres were acetylated using acetic anhydride in methanol. It was found that 88% of the amine groups were acetylated within 30 minutes at 40 °C. The effects of temperature, time, ratio of anhydride to amine groups and the addition of water were studied; it was found that the addition of water to the methanol anhydride mixture greatly accelerated the reaction. Some O-acetylation was noticed in the reaction and this was removed by a treatment using 1 M aqueous NaOH. The changes in fibre properties after acetylation were also studied. It was found that after the acetylation process, the fibre had a better thermal stability and improved dry and wet strength. However, the fibre lost its chelating ability when substantially acetylated.
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Agboh, Ochayi Christopher. "The production of fibres from chitin". Thesis, University of Leeds, 1986. http://etheses.whiterose.ac.uk/11256/.
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Roudier, Agnès. "Analyse multi-échelle du comportement hygro-mécanique des fibres de lin". Phd thesis, Université Blaise Pascal - Clermont-Ferrand II, 2012. http://tel.archives-ouvertes.fr/tel-00741951.
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Les fibres végétales utilisées comme renfort dans les matériaux composites présentent des propriétés mécaniques spécifiques concurrentielles par rapport à celles des fibres de verre. De plus, elles ont l'avantage d'être renouvelables et recyclables. Toutefois, leur principal inconvénient est leur sensibilité à l'humidité, ce qui a pour conséquence d'induire une baisse des propriétés mécaniques ainsi d'une décohésion de l'interface fibre/matrice. L'objectif principal de cette thèse est d'étudier l'influence de l'humidité sur le comportement hygro-mécanique de fibres de lin. La première partie de mes travaux a été consacrée à la caractérisation des propriétés hygroscopiques et mécaniques de la fibre et du composite. Dans la deuxième partie, deux modèles multi-échelles, l'un analytique et l'autre numérique, ont été développés pour l'estimation des propriétés hygro-mécaniques des fibres élémentaires de lin. Ils utilisent en partie pour données d'entrée, les propriétés identifiées dans la première partie.
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Pomel, Catherine. "Contribution à l'étude de matériaux composites renforcés par des fibres de lin". Nantes, 2003. http://www.theses.fr/2003NANT2029.
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Les fibres végétales, en tant que charges dans les matériaux composites, sont couramment utilisées. En revanche, peu d'expérimentations ont été menées avec des fibres végétales en tant que renfort. Bien que les fibres végétales, et notamment les fibres de lin, présentent un certain nombre d'inconvénients (propriétés géométriques et mécaniques variables, qualité variant d'une production à l'autre, présence de défauts. . . ), elles présentent également des avantages (biodégradabilité, faible densité, module élevé. . . ). Les différentes étapes possibles permettant de passer de la fibre de lin au matériau composite industriel à base de textiles de lin ont été analysées. . .
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Girault, Raynald. "Caractérisation biochimique des polymères incrustant les parois secondaires des fibres de lin". Rouen, 1999. http://www.theses.fr/1999ROUES055.
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Les fibres élémentaires dépectinisées de lin mature (linum usitatissimum L. ) renferment, en association forte avec les dépôts secondaires de cellulose, des polymères incrustants variés. Ces polymères pourraient avoir une influence notable sur les propriétés mécaniques, et notamment sur la résistance aux tensions, de ces fibres. De nombreux polymères incrustant les parois secondaires des fibres élémentaires dépectinisées de lin ont ete caractérisés, après extraction chimique ou enzymatique. Le composé majoritaire est un long (1→4)-galactane. Ce polymère pourrait constituer les ramifications latérales de rhamnogalacturonanes de type I. Outre les polysaccharides, des protéines ont aussi été identifiées. L'une de ces protéines appartient au groupe des protéines riches en leucine, les deux autres appartenant au groupe des protéines pariétales de structure, et plus particulièrement aux protéines riches en glycine et aux arabinogalactane-protéines. Le rôle possible de chacun de ces incrustants dans les fibres élémentaires de lin est abordé. La possibilité d'une interaction entre les arabinogalactane-protéines et les (1→4)-galactanes a été mise en évidence. Les modalités de cette interaction sont discutées.
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Huis, Rudy. "Régulation des « gènes lignine » chez le lin à fibres, Linum usitatissimum L". Thesis, Lille 1, 2012. http://www.theses.fr/2012LIL10050.
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Le lin est une plante annuelle cultivée pour ses fibres longues et ses graines oléagineuses. Les fibres sont traditionnellement employées dans l’industrie textile et, depuis peu, incorporées dans des agro-matériaux. Les fibres longues sont situées dans la tige entre l’écorce et le bois, en périphérie du phloème. Les cellules fibreuses sont essentiellement composées de parois secondaires dans lesquelles la teneur en lignine est faible (2% à 4%). C’est pourquoi, elles sont qualifiées d’« hypolignifiées ». En effet, une paroi secondaire « classique » est généralement composée de 40 à 50% de cellulose et de 20 à 30% de lignine. Ainsi, nous suggérons l'existence d'une régulation particulière lors de la mise en place de cette paroi. On ne retrouve ce type de paroi secondaire que dans de très rares cas chez les végétaux comme dans d'autres fibres phloémiennes présentes par exemple chez le chanvre, mais aussi dans les couches G du bois de tension. Le lin est donc un bon modèle d’étude pour la compréhension de la régulation de la lignification des parois secondaires. Mes travaux visent ainsi à améliorer nos connaissances sur les mécanismes cellulaires et moléculaires permettant de mettre en place une telle paroi. Les raisons pour lesquelles ces fibres contiennent de faibles quantités de lignine demeurent complètement inconnues. Différentes pistes peuvent être explorées et parmi celles-ci, l'existence de phénomènes de régulations géniques spécifiques à ces types cellulaires. Les travaux réalisés dans le cadre de ma thèse s'inscrivent dans l'hypothèse de l'existence d'une régulation transcriptionnelle à ce niveauFlax is an annual species cultivated for its fibers and seed oil. Flax bast fibers are traditionally used in textiles and since more recently, they are integrated in composite materials used in automobile and construction industries. These fibers are located between the epidermis and the secondary xylem. Their cell walls contain unusually low amounts of lignin (2 %) compared to more classical secondary cell walls (between 20 and 30 %). So we suggest the existence of a special regulatory control of lignification within these fibers. The same types of cell walls also exist in other bast fibers such as in hemp but also in the G-layer of tension wood. Flax is a suitable model to gain knowledge on the lignification process. The reason why the bast fibers are hypolignified is completely unknown and may be due to a regulatory control at the gene transcription level
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Chilali, Abderrazak. "Étude expérimentale et modélisation de la durabilité des biocomposites à fibres de lin". Thesis, Reims, 2017. http://www.theses.fr/2017REIMS003/document.
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Dans cette étude doctorale, nous proposons d’étudier la durabilité de deux matériaux composites à matrices thermodurcissable et thermoplastique renforcées par des tissus sergé de lin. Nous analysons d’abord la cinétique de diffusion d'eau dans les deux composites par identification de leurs paramètres de diffusion 3D, via une approche d’optimisation basée sur les modèles de Fick et de Langmuir 3D. Nous étudions ensuite l’effet de plusieurs paramètres géométriques et l’orientation des fibres sur la cinétique de diffusion d’eau au sein des deux composites. Nous analysons par la suite l'effet du vieillissement hydrique sur leurs propriétés élastiques et à la rupture. Enfin, nous proposons une analyse numérique par éléments finis de la diffusion d’eau au sein des deux composites et de leur comportement hydro-élastique. Nous estimons ainsi les paramètres de diffusion de la fibre de lin et des matrices à travers une approche numérique inverse, en décrivant la section et l’ondulation des mèches de lin au sein des deux matériaux. Nous montrons en particulier que les composites non vieillis présentent un comportement mécanique proche de l'effet Kaiser. Cependant, les composites vieillis présentent clairement un effet Felicity, ce qui indique la présence significative d’endommagements induits par l’absorption d'eau. Nous affirmons enfin que l’analyse numérique permet d’identifier d’importantes concentrations de contraintes pouvant induire des endommagements microstructuraux au sein des composites étudiésIn this thesis work, we study the durability of two twill flax fabrics reinforced thermosetting and thermoplastic composites. Firstly, the diffusion behaviour of these composites is investigated by identifying their 3D Fick’s and Langmuir’s diffusion parameters using an optimization algorithm. The influence of several geometric parameters and fibre orientation on their 3D moisture diffusion is also studied. Then, we analyse the effect of water ageing on their elastic and failure properties. Finally, a numerical finite element analysis is performed in order to study their diffusive and hydro-mechanical behaviour. The water diffusion parameters of the flax fibre and the used resins are estimated by a numerical inverse analysis exploiting experimental water uptake data. The heterogeneity of the studied composites is considered by modelling the twill weave fabrics undulation of their unit-cell. In particular, the mechanical behaviour of the unaged composites is found to exhibit a Kaiser effect contrary to the aged materials which exhibit a significant Felicity effect synonymous of substantial damage induced by water ageing. Besides, it is found that high mechanical stress concentrations are developed at the fibre-matrix interface, which could cause damage initiation and lead to the final composite failure
Libros sobre el tema "Production des fibres de lin"
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Tankard, Mark Harry. The production of high tenacity polyolefins fibres. Manchester: University of Manchester, 1995.
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Steadman, Stuart Charles. The in-situ production of polyethylene fibres from polymer blends. Uxbridge: Brunel University, 1990.
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Wanrong, Wang, ed. Wu tai guang jing: Lin Kehua de she ji yu chen si. Taibei Shi: Yuan liu chu ban shi ye gu fen you xian gong si, 2003.
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Dam, J. E. G. van. y Commissionof the European Communities. Directorate-General for Science, Research and Development., eds. Increased application of domestically produced plant fibres in textiles, pulp and paper production, and composite materials. [Brussels]: European Commission, Directorate-General XII Science, Research and Development, 1994.
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Tribunal canadien du commerce extérieur. Rapport sur la production au Canada de certains fils et fibres et de certains tissus pour vêtements. [Ottawa, Ont.]: Tribunal candien du commerce extérieur, 2005.
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Ke zai sheng neng yuan fa dian: Zhong Mei liang guo mian lin de ji yu he tiao zhan = The power of renewables : opportunities and challenges for China and the United States. Beijing: Ke xue chu ban she, 2012.
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Zhongguo shi da xi ju dao yan da shi: Jiao Juyin, Huang Zuolin, Xu Xiaozhong, Lin, Zhaohua, Chen Yu, Luo Jinlin, Hu Weimin, Chen Mingzheng, Chen Xinyi, Cao Qijing. Beijing: Zhongguo ren min da xue chu ban she, 2005.
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Beyreuther, Roland. Dynamics of fibre formation and processing: Modelling and application in fibre and textile industry. Berlin: Springer, 2007.
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Britain, Great. Production of Man-Made Fibres. Stationery Office Books, 1993.
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Britain, Great. Production of Man-Made Fibres. Stationery Office Books, 1989.
Buscar texto completoCapítulos de libros sobre el tema "Production des fibres de lin"
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Mimra, Christopher, Vincent Krein, Racim Radjef, Bronwyn Fox y Peter Middendorf. "Detection of Gaps and Overlaps in Laser Line Triangulation Data of Dry Fibre Tape Layups Using Image Projection". En Advances in Automotive Production Technology – Towards Software-Defined Manufacturing and Resilient Supply Chains, 253–65. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-27933-1_24.
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AbstractA major cost driver in the production of carbon composite parts is the quality inspection, which to this day relies on manual investigation by a trained worker. Gaps and overlaps in the layups are to be detected because they are proven to be detrimental towards the mechanical properties of the final part. In recent works, laser line triangulation sensors have been applied to inspect layups of prepreg tapes and non-crimp fabric material. These sensors create a 3D point cloud of the specimens surface. This is then evaluated by conversion into a grey-scale image and a subsequent image processing algorithm. However, the most commonly used algorithms fail to differentiate between defects and small, acceptable irregularities, such as welding spots, slits and single fibres which stick out.The aim of this research is to develop a reliable evaluation method for scans of dry fibre tape layups. An overview over the different groups of algorithms is provided, image projection is selected and compared to algorithms which have been proven to work best on pre-pregs. While the common algorithms fail to classify a test set of dry fibre specimen, image projection can reach a true positive rate of 100% and a false positive rate of 19%. The proposed setup can be a centrepiece of a future in-line quality inspection system for dry fibre layups which has potential for a significant decrease of the manufacturing costs.
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Rathinamoorthy, R. y M. Senthilkumar. "Elastane fibres – production and properties". En Elastane in Sports and Medical Textiles, 1–10. Boca Raton: CRC Press, 2023. http://dx.doi.org/10.1201/9780429094804-1.
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Chaudhry, Muhammed Rafiq. "Cotton Production and Processing". En Industrial Applications of Natural Fibres, 219–34. Chichester, UK: John Wiley & Sons, Ltd, 2010. http://dx.doi.org/10.1002/9780470660324.ch10.
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Thangavelu, Karthik y Krishna Bala Subramani. "Sustainable Biopolymer Fibers—Production, Properties and Applications". En Sustainable Fibres for Fashion Industry, 109–40. Singapore: Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-0522-0_5.
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Yano, E., N. Urano y P. H. Evans. "Reactive Oxygen Metabolite Production Induced by Mineral Fibres". En Mechanisms in Fibre Carcinogenesis, 433–38. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4684-1363-2_36.
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Jain, Archana, Deepali Rastogi y Bhawana Chanana. "Product Development Using Cornhusk Fibres—A Sustainable Initiative". En Sustainable Textiles: Production, Processing, Manufacturing & Chemistry, 251–74. Singapore: Springer Nature Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-0878-1_10.
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Rawnsley, Ming-Yeh T. "Stars as Production and Consumption: A Case Study of Brigitte Lin". En East Asian Film Stars, 190–204. London: Palgrave Macmillan UK, 2014. http://dx.doi.org/10.1057/9781137029195_13.
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Engert, Michelle, Kim Torben Werkle y Hans-Christian Möhring. "Determination of the Thermal Properties of Pre-stressed Fiber-Reinforced Polymer Concrete". En Lecture Notes in Production Engineering, 278–85. Cham: Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-34486-2_20.
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AbstractWith its low thermal conductivity and high thermal capacity, polymer concrete has excellent thermal properties that when used in machine tools ensure increased accuracy of the manufactured parts. Polymer concrete has been used successfully in machine tool construction for many years in the form of machine beds. The aforementioned thermal properties in combination with a low density, high damping and a lower primary energy requirement also make polymer concrete interesting for use as a structural component. However, the comparatively low tensile strength and creep tendency of the material pose a challenge here. One approach to increase the tensile strength of the material is the integration of prestressed carbon fibres into the material. In order to clarify the suitability of this hybrid material, its temperature behaviour is investigated in this paper. The focus is on the investigation of residual stresses that arise during heating, which result from the combination of the positive thermal expansion coefficient of polymer concrete with the negative thermal expansion coefficient of the carbon fibres. In addition, the flexural properties of pure polymer concrete and of pre-stressed fibre-reinforced polymer concrete are determined at different test temperatures within the scope of this paper. It is shown that the prestressing of fiber-reinforced polymer concrete leads to an improvement of the flexural strength and the stiffness of polymer concrete.
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Gussone, J. G. y J. M. Hausmann. "Electrolytic Production of Matrix Coated Fibres for Titanium Matrix Composites". En Molten Salts Chemistry and Technology, 319–28. Chichester, UK: John Wiley & Sons, Ltd, 2014. http://dx.doi.org/10.1002/9781118448847.ch4j.
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Thadepalli, Srivani y Shreyasi Roy. "Implications of Sustainability on Textile Fibres and Wet Processing, Barriers in Implementation". En Sustainable Textiles: Production, Processing, Manufacturing & Chemistry, 133–56. Singapore: Springer Singapore, 2022. http://dx.doi.org/10.1007/978-981-19-0538-4_6.
Texto completoActas de conferencias sobre el tema "Production des fibres de lin"
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Lengersdorf, Michael, Jörg Multhoff y Thomas Gries. "Braiding: A New Production Method Approach for Composite Pressure Vessels in Automotive Applications". En ASME 2014 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/pvp2014-28420.
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With the first serial production of a hydrogen fuel cell car announced to enter the market in 2015, there is a prospective mass market for mobile pressure vessel applications. In automotive applications three factors are mainly decisive for a successful integration: low weight, a competitive price range and a safe operation implementation. Composite vessels can fulfill these demands. State-of-the art for the production of the composite structure is wet-filament winding. It is well established for smaller production volumes. However the potential of rise in output is limited. In filament winding only a limited number of usually 1–10 fibres is layed onto a mandrel at once. Braiding in comparison allows the simultaneously deposition of a multitude of fibres, standard machinery allow braiding of more than 200 fibres. A filament wound composite structure lacks fracture resistance under certain load cases. Composite structures known to have better fracture resistance are interlaced fibre architectures, such as braid. This applies especially for impact performance [7]. The braiding process strongly depends on the desired product. The machinery has to be chosen accordingly to application regarding e.g. the number of fibre carriers and their quantities. In automotive applications the dimensions are limited to a certain range due to available build space in the car. This paper will show which parameters have to be considered when setting up a production line for braided pressure vessels. This is done against the background of typical pressure vessel dimensions in automotive applications.
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Davies, Peter, Patrice Baron, Karine Salomon, Charles Bideaud, J. P. Labbe´, Ste´phane Toumit, Michel Francois, Francois Grosjean, Tony Bunsell y A. G. Moysan. "Influence of Fibre Stiffness on Deepwater Mooring Line Response". En ASME 2008 27th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2008. http://dx.doi.org/10.1115/omae2008-57147.
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Polyester fibre ropes are now an accepted solution for deepwater mooring of production platforms and a single high tenacity fibre grade is widely used. Few studies of other fibres have been reported but polyesters can be produced with a range of properties by varying drawing parameters, and other stiffer fibres are also available. This paper presents a study of these alternative fibre rope solutions, performed within the French Mooring Line project. First, in order to obtain the input data necessary for mooring line analyses an extensive test program was performed to characterize polyester, improved polyester, PEN, LCP, aramid and HMPE fibre ropes from yarns up to 800 ton break load ropes. Tests at different scales have allowed property transfer to be quantified. Rope modelling has been used in parallel to examine the influence of material and structural parameters. Then, using these data, a series of analyses was run by engineering contractors, which quantified the benefits of higher stiffness for different supports (semi-submersible, production platform and offloading buoy) down to 2500 meter depth. Under certain conditions the stiffer ropes can result in significantly reduced rope diameter and weight.
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Feherty, Craig, Andrew Garioch y Annabel Green. "Disposable Fibre Optic Intervention System: Case Study of Successful Leak Detection Offshore North Sea". En SPE Offshore Europe Conference & Exhibition. SPE, 2021. http://dx.doi.org/10.2118/205425-ms.
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Abstract Maintaining well integrity is critical to sustaining production from mature and aging fields. Disposable fibre optic technology has been deployed in wells in the North Sea to locate known tubing leaks in the completion. The disposable fibre optic intervention system releases a probe into the well to enable the deployment of bare fibre optic line. The fibres are released from the probe as it descends into the well. In the presented case study, the probe contained both single-mode and multi-mode fibre optic lines to enable simultaneous Distributed Temperature Sensing (DTS) and Distributed Acoustic Sensing (DAS) surveys to be performed. Once deployed in the well, pressure manipulation programs were performed to activate any tubing or casing leaks while acquiring DTS and DAS data. As a result of the exceptional sensitivity of the bare fibres and the effective coupling of the fibre with the tubing wall the technology is shown to be highly effective in detecting leaks and confirming barrier integrity. In the presented example a leak was located along with the direction and rate of the fluid movement in the ‘B’ annulus. The simplicity of the system and highly efficient operations greatly reduced survey times in comparison to conventional intervention techniques thereby greatly reducing the cost of intervention. It can be demonstrated that the disposable fibre optic deployment system provides a game changing and cost-effective solution for both leak detection and determining liquid levels in the wells. The disposable fibre solution is a unique deployment method which provides an alternative to conventional well surveys, reducing the complexity, time and cost to acquire valuable distributed well data. This is the first case history published for this technology in leak detection application.
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Rudolf, Maja, Irena Bates, Ivana Plazonić, Valentina Radić Seleš, Katja Petric Maretić y Marija Magdalena Mendeš. "Evaluation of the line and edge quality of printed letters on recycled paper with straw pulp". En 11th International Symposium on Graphic Engineering and Design. University of Novi Sad, Faculty of technical sciences, Department of graphic engineering and design, 2022. http://dx.doi.org/10.24867/grid-2022-p33.
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Traditional papermaking is based on the use of an aqueous suspension consisting of cellulose fibres obtained by processing wood, non-wood plants or waste paper. With growing environmental concerns regarding deforestation and CO2 production, the paper industry has been always looking for new sources of non-wood pulp that would produce papers of similar quality to those made from wood pulp. Cereal straw from wheat, barley or triticale crops that remains on fields as a residue after grain harvesting has proven to be a good substitute for virgin wood fibres needed in the production of recycled paper. In this study, the quality of printed text on recycled paper with added straw pulp is evaluated mainly based on the line and edge characteristics of the printed letters. For this purpose, three types of laboratory paper substrates were first prepared using recycled wood pulp with the addition of 30% wheat, barley, or triticale straw pulp. The same letter pattern was printed with black ink on each paper substrate at a standard size of 12 pt with two common typefaces: Arial and Times New Roman. The quality of the printed letters was assessed through the measured print quality parameters such as blurriness, raggedness, fill and contrast. The resulting measurements were compared with the results obtained on the reference and control samples made exclusively from recycled wood pulp as a substrate from laboratory and commercial production. In terms of fill and contrast values, the uniformity of lines printed on the recycled papers with added straw pulp is the same or very similar to the reference and control papers. Letters printed in Arial (sans-serif) typeface show slightly better reproduction quality than letters printed in Times New Roman (serif) typeface. The measured parameters blurriness and raggedness of all laboratory-made paper substrates (with and without straw pulp) had similar values between 0.17 mm and 0.20 mm, resulting in a very similar reproduction quality compared to the reference paper substrate.
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Gabriel, C. y H. Horia. "Integrating sensor devices in a LIN bus network". En 26th International Spring Seminar on Electronics Technology: Integrated Management of Electronic Materials Production, 2003. IEEE, 2003. http://dx.doi.org/10.1109/isse.2003.1260504.
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Williams, Glen M., Martin A. Putnam, Tsung E. Tsai, Charles G. Askins y E. Joseph Friebele. "Growth Dynamics of Fiber Bragg Gratings Written with a KrF Excimer Laser". En Photosensitivity and Quadratic Nonlinearity in Glass Waveguides. Washington, D.C.: Optica Publishing Group, 1995. http://dx.doi.org/10.1364/pqn.1995.sua.5.
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For the production of single shot fiber Bragg gratings1-3 in-line during the fiber drawing process, a knowledge of the effects of exposure conditions and material composition of fiber can be of crucial importance. During in-line production, one is not afforded the possibility of exposing the fiber incrementally to repeated laser shots until the correct grating reflectivity is achieved. Single shot writing of gratings in many different types of fibers indicates that the maximum index change in the Type I regime (<1 J/cm2, yielding a spectrally narrow and smooth reflectivity) from a single shot is on the order 10-5. For many applications (ie sensor arrays) this index change produces reflectivites that are more than adequate for good system performance. However, for certain applications greater reflectivies are required. In an effort to better control and possibly improve the photosensitivity of optical fibers at 248 nm we studied the growth dynamics of fiber Bragg gratings in various fibers under various exposure conditions.
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Matthijsse, Pieter. "The PCVD Process For Large Scale Production Of Telecommunication Fibres". En 1985 International Technical Symposium/Europe, editado por Remy Bouillie. SPIE, 1986. http://dx.doi.org/10.1117/12.950950.
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Kuijt, Gerard. "Production Of Optical Fibres For Telecommunication With The Pcvd Process". En Hague International Symposium, editado por Anna M. Verga Scheggi. SPIE, 1987. http://dx.doi.org/10.1117/12.941079.
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Kuijt, Gerard. "Production Of Optical Fibres For Telecommunication With The PCVD Process". En Hague International Symposium, editado por Jacques Lucas. SPIE, 1987. http://dx.doi.org/10.1117/12.941142.
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Kuijt, Gerard. "Production Of Optical Fibres For Telecommunication With The PCVD Process". En Hague International Symposium, editado por M. J. Adams. SPIE, 1987. http://dx.doi.org/10.1117/12.941179.
Texto completoInformes sobre el tema "Production des fibres de lin"
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Granot, David, Scott Holaday y Randy D. Allen. Enhancing Cotton Fiber Elongation and Cellulose Synthesis by Manipulating Fructokinase Activity. United States Department of Agriculture, 2008. http://dx.doi.org/10.32747/2008.7613878.bard.
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a. Objectives (a) Identification and characterization of the cotton fiber FRKs; (b) Generating transgenic cotton plants overproducing either substrate inhibited tomato FRK or tomato FRK without substrate inhibition; (c) Generating transgenic cotton plants with RNAi suppression of fiber expressed FRKs; (d) Generating Arabidopsis plants that over express FRK1, FRK2, or both genes, as additional means to assess the contribution of FRK to cellulose synthesis and biomass production. b. Background to the topic: Cellulose synthesis and fiber elongation are dependent on sugar metabolism. Previous results suggested that FRKs (fructokinase enzymes that specifically phosphorylate fructose) are major players in sugar metabolism and cellulose synthesis. We therefore hypothesized that increasing fructose phosphorylation may enhance fiber elongation and cellulose synthesis in cotton plants. Accordinlgy, the objectives of this research were: c. Major conclusions and achievements: Two cotton FRKs expressed in fibers, GhFRK2 and GhFRK3, were cloned and characterized. We found that GhFRK2 enzyme is located in the cytosol and GhFRK3 is located within plastids. Both enzymes enable growth on fructose (but not on glucose) of hexose kinase deficient yeast strain, confirming the fructokinase activity of the cloned genes. RNAi constructs with each gene were prepared and sent to the US collaborator to generate cotton plants with RNAi suppression of these genes. To examine the effect of FRKs using Arabidopsis plants we generated transgenic plants expressing either LeFRK1 or LeFRK2 at high level. No visible phenotype has been observed. Yet, plants expressing both genes simultaneously are being created and will be tested. To test our hypothesis that increasing fructose phosphorylation may enhance fiber cellulose synthesis, we generated twenty independent transgenic cotton plant lines overexpressing Lycopersicon (Le) FRK1. Transgene expression was high in leaves and moderate in developing fiber, but enhanced FRK activity in fibers was inconsistent between experiments. Some lines exhibited a 9-11% enhancement of fiber length or strength, but only one line tested had consistent improvement in fiber strength that correlated with elevated FRK activity in the fibers. However, in one experiment, seed cotton mass was improved in all transgenic lines and correlated with enhanced FRK activity in fibers. When greenhouse plants were subjected to severe drought during flowering and boll development, no genotypic differences in fiber quality were noted. Seed cotton mass was improved for two transgenic lines but did not correlate with fiber FRK activity. We conclude that LeFRK1 over-expression in fibers has only a small effect on fiber quality, and any positive effects depend on optimum conditions. The improvement in productivity for greenhouse plants may have been due to better structural development of the water-conducting tissue (xylem) of the stem, since stem diameters were larger for some lines and the activity of FRK in the outer xylem greater than observed for wild-type plants. We are testing this idea and developing other transgenic cotton plants to understand the roles of FRK in fiber and xylem development. We see the potential to develop a cotton plant with improved stem strength and productivity under drought for windy, semi-arid regions where cotton is grown. d. Implications, scientific and agricultural: FRKs are probably bottle neck enzymes for biomass and wood synthesis and their increased expression has the potential to enhance wood and biomass production, not only in cotton plants but also in other feed and energy renewable plants.
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Beckman, Ivan. Development of alternative air filtration materials and methods of analysis. Engineer Research and Development Center (U.S.), junio de 2023. http://dx.doi.org/10.21079/11681/47188.
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Development of high efficiency particulate air (HEPA) filters demonstrate an effort to mitigate dangerous aerosol hazards at the point of production. The nuclear power industry installs HEPA filters as a final line of containment of hazardous particles. An exploration of analytical, experimental, computational, and machine learning models is presented in this dissertation to advance the science of air filtration technology. This dissertation studies, develops, and analyzes alternative air filtration materials and methods of analysis that optimize filtration efficiency and reduce resistance to air flow. Alternative nonwoven filter materials are considered for use in HEPA filtration. A detailed review of natural and synthetic fibers is presented to compare mechanical, thermal, and chemical properties of fibers to desirable characteristics for air filtration media. Digital replication of air filtration media enables coordination among experimental, analytical, machine learning, and computational air filtration models. The value of using synthetic data to train and evaluate computational and machine learning models is demonstrated through prediction of air filtration performance, and comparison to analytical results. This dissertation concludes with discussion on potential opportunities and future work needed in the continued effort to advance clean air technologies for the mitigation of a global health and safety challenge.
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Short, Samuel. Alternatives to single-use plastics in food packaging and production. Food Standards Agency, agosto de 2023. http://dx.doi.org/10.46756/sci.fsa.taf512.
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This rapid evidence assessment undertaken by RSM UK Consulting LLP (RSM) and Dr Samuel Short (University of Cambridge) aimed to develop an understanding of the alternatives to single-use plastics in food packaging and production in terms of their risks and opportunities, as well as potential future developments. Literature from within and beyond the UK was gathered from academic databases and reports published by government and non-governmental organisations such as environmental charities. Evidence from the literature was supplemented by findings from a workshop with experts in the field from a variety of industries such as academia, manufacturing, and government. Two broad groups of alternatives were established: material/product alternatives (traditional materials, natural fibres, biopolymers synthesised from biomass, biopolymers synthesised from bioderived monomers, biopolymers produced by microorganisms) and, and system/process alternatives (reducing, reusing, and recycling food packaging and, active and intelligent packaging). These alternatives and systems vary considerably in terms of their properties, such as effectiveness as a barrier to moisture or contamination, convenience for consumers, production costs, and potential for commercialisation. Our review also highlighted gaps in the current knowledge, for example in terms of consumer acceptance and carbon footprint at each stage of their life cycle. The capacity to produce bioplastics (i.e. biopolymers that look and feel similar to conventional plastics but are made from natural materials rather than fossil fuels and are biodegradable or compostable) is anticipated to increase globally from 2.1 million tonnes in 2019 to 6.3 million tonnes by 2027. This growth appears to be enabled by increased consumer awareness of environmental issues and existing regulation and legislation encouraging the development and establishment of a circular economy. However, there are barriers that may challenge this growth. These include already established industry regimes, high production cost of novel materials and a lack of waste management guidance. Overall, fossil-based conventional plastics are a very cheap, versatile material compared to the alternatives currently being developed and tested. Because of this, they might remain the preferred industry choice for certain applications, while alternatives continue to be optimised and commercially scaled. To add to this, the reviewed evidence suggests that there is unlikely to be one single solution to the single-use plastics problem. The solution will likely draw on a range of materials and systems depending on food type and context.
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Baldos, Uris Lantz y Erwin Corong. Development of GTAP 10 Land Use and Land Cover Data Base for years 2004, 2007, 2011 and 2014. GTAP Research Memoranda, noviembre de 2020. http://dx.doi.org/10.21642/gtap.rm36.
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Understanding the challenges of achieving environmental sustainability goals given future demand for food, fiber and fuel requires economic frameworks that incorporate spatially explicit information on land use and land cover (LULC). The GTAP LULC Data Base and its variants have been extensively used in a wide variety of applications aimed at examining the land-environment-energy nexus (Golub et al., 2012; Hertel et al., 2010; Johnson et al., 2019; Liu et al., 2014; Peña-Lévano et al., 2019; Stevenson et al., 2013; Taheripour et al., 2010; Taheripour & Tyner, 2012). The first release of the GTAP LULC Data Base combines geospatial data on land use and land cover into GTAP 6 Data Base – benchmarked to year 2001 (GTAP LULC v6). The methodology for creating and using this database is well documented (Lee et al., 2009; C. Monfreda et al., 2009; Sohngen et al., 2008). Succeeding updates of the GTAP LULC Data Base (namely v7 and v8 for 2004 and v8 for 2004, 2007) relied on readily available but aggregated GTAP LULC v6, albeit using national-level data from FAOSTAT (2020) (Avetisyan et al., 2010; Baldos & Hertel, 2012). Starting with GTAP 9, LULC was created directly from the latest, high-resolution (i.e. 5-minute) spatial land cover and land use maps in combination with national-level statistics (Baldos, 2017). This memorandum documents the development of the GTAP LULC version10A which is based on the GTAP v10A Data Base for years 2004, 2007, 2011 and 2014 (Aguiar et al., 2019). This update heavily relies on the methodology for creating GTAP LULC v9 which downscales national-level land cover and crop production statistics from FAOSTAT (2020) using publicly available spatial data (see Appendix I).
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Ghanim, Murad, Joe Cicero, Judith K. Brown y Henryk Czosnek. Dissection of Whitefly-geminivirus Interactions at the Transcriptomic, Proteomic and Cellular Levels. United States Department of Agriculture, febrero de 2010. http://dx.doi.org/10.32747/2010.7592654.bard.
Texto completoResumen
Our project focuses on gene expression and proteomics of the whitefly Bemisia tabaci (Gennadius) species complex in relation to the internal anatomy and localization of expressed genes and virions in the whitefly vector, which poses a major constraint to vegetable and fiber production in Israel and the USA. While many biological parameters are known for begomovirus transmission, nothing is known about vector proteins involved in the specific interactions between begomoviruses and their whitefly vectors. Identifying such proteins is expected to lead to the design of novel control methods that interfere with whitefly-mediated begomovirus transmission. The project objectives were to: 1) Perform gene expression analyses using microarrays to study the response of whiteflies (B, Q and A biotypes) to the acquisition of begomoviruses (Tomato yellow leaf curl (TYLCV) and Squash leaf curl (SLCV). 2) Construct a whitefly proteome from whole whiteflies and dissected organs after begomovirus acquisition. 3) Validate gene expression by q-RTPCR and sub-cellular localization of candidate ESTs identified in microarray and proteomic analyses. 4) Verify functionality of candidate ESTs using an RNAi approach, and to link these datasets to overall functional whitefly anatomical studies. During the first and second years biological experiments with TYLCV and SLCV acquisition and transmission were completed to verify the suitable parameters for sample collection for microarray experiments. The parameters were generally found to be similar to previously published results by our groups and others. Samples from whole whiteflies and midguts of the B, A and Q biotypes that acquired TYLCV and SLCV were collected in both the US and Israel and hybridized to B. tabaci microarray. The data we analyzed, candidate genes that respond to both viruses in the three tested biotypes were identified and their expression that included quantitative real-time PCR and co-localization was verified for HSP70 by the Israeli group. In addition, experiments were undertaken to employ in situ hybridization to localize several candidate genes (in progress) using an oligonucleotide probe to the primary endosymbiont as a positive control. A proteome and corresponding transcriptome to enable more effective protein identification of adult whiteflies was constructed by the US group. Further validation of the transmission route of begomoviruses, mainly SLCV and the involvement of the digestive and salivary systems was investigated (Cicero and Brown). Due to time and budget constraints the RNAi-mediated silencing objective to verify gene function was not accomplished as anticipated. HSP70, a strong candidate protein that showed over-expression after TYLCV and SLCV acquisition and retention by B. tabaci, and co-localization with TYLCV in the midgut, was further studies. Besides this protein, our joint research resulted in the identification of many intriguing candidate genes and proteins that will be followed up by additional experiments during our future research. To identify these proteins it was necessary to increase the number and breadth of whitefly ESTs substantially and so whitefly cDNAs from various libraries made during the project were sequenced (Sanger, 454). As a result, the proteome annotation (ID) was far more successful than in the initial attempt to identify proteins using Uniprot or translated insect ESTs from public databases. The extent of homology shared by insects in different orders was surprisingly low, underscoring the imperative need for genome and transcriptome sequencing of homopteran insects. Having increased the number of EST from the original usable 5500 generated several years ago to >600,000 (this project+NCBI data mining), we have identified about one fifth of the whitefly proteome using these new resources. Also we have created a database that links all identified whitefly proteins to the PAVEdb-ESTs in the database, resulting in a useful dataset to which additional ESTS will be added. We are optimistic about the prospect of linking the proteome ID results to the transcriptome database to enable our own and other labs the opportunity to functionally annotate not only genes and proteins involved in our area of interest (whitefly mediated transmission) but for the plethora of other functionalities that will emerge from mining and functionally annotating other key genes and gene families in whitefly metabolism, development, among others. This joint grant has resulted in the identification of numerous candidate proteins involved in begomovirus transmission by B. tabaci. A next major step will be to capitalize on validated genes/proteins to develop approaches to interfere with the virus transmission.