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Auswahl der wissenschaftlichen Literatur zum Thema „Flax fibre production“
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Zeitschriftenartikel zum Thema "Flax fibre production"
1
SINGH, A. K., MUKESH KUMAR und S. MITRA. „Carbon footprint and energy use in jute and allied fibre production“. Indian Journal of Agricultural Sciences 88, Nr. 8 (21.08.2018): 1305–11. http://dx.doi.org/10.56093/ijas.v88i8.82579.
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The study examines carbon and energy footprints of jute, kenaf, sunnhemp and flax fibre production systems. Energy productivity was lowest in flax fibre production as compared to other fibre crops. Flax fibre production consumed more chemical fertilizer, diesels, pesticides and seed energy in comparison to other fibre crops. The carbon footprints of the all fibres crops did not differ significantly and were in the order of 566, 520, 445 and 423 kg CO2-eq/tonne of fibre for jute, flax, kenaf and sunnhemp, respectively. The carbon based sustainability index for jute (2.27) and kenaf (2.07) were highest due to better carbon use efficiency. Sustainability index of flax was negative (-0.67) due to higher carbon emission. Fertilization and fibre processing contributed most to GHG emissions. Overall, the carbon footprint of bast fibres was 20–50% lower than that of synthetic/artificial fibres.
2
DIMMOCK, J. P. R. E., S. J. BENNETT, D. WRIGHT, G. EDWARDS-JONES und I. M. HARRIS. „Agronomic evaluation and performance of flax varieties for industrial fibre production“. Journal of Agricultural Science 143, Nr. 4 (August 2005): 299–309. http://dx.doi.org/10.1017/s0021859605005277.
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Flax fibre for industrial purposes differs from that for linen production, although the agronomic factors that influence fibre development and which factors are most important for industrial fibre production have still to be defined. A description of variations in the performance of fibre flax varieties is also necessary as current guidance relates to the European market rather than the UK. Field trials were sown in 2002 and 2003 at the Henfaes Research Centre in north Wales, investigating 29 and 26 varieties, respectively, of European fibre flax and dual-purpose flax varieties. In 2002 a nitrogen treatment was included in the trial with two treatments, 40 kg/ha and 80 kg/ha. Varieties were evaluated for 20 agronomic and fibre production variables, and the differences between the varieties were analysed using analysis of variance (ANOVA) and principal components analysis (PCA). The higher nitrogen rate was found to increase crop lodging, although some varieties were found to be more susceptible than others. Environment had a strong influence on crop success, with some varieties showing more year to year stability than others. PCA allowed those varieties that were the highest yielding, highest fibre producers and showed the best stability across the 2 years to be identified. Understanding the agronomic results presented and discussed here is important if fibre flax production is to become economically viable in the UK.
3
Tchana Toffe, Gilles, Sikiru Oluwarotimi Ismail, Diogo Montalvão, Jason Knight und Guogang Ren. „A Scale-up of Energy-Cycle Analysis on Processing Non-Woven Flax/PLA Tape and Triaxial Glass Fibre Fabric for Composites“. Journal of Manufacturing and Materials Processing 3, Nr. 4 (01.11.2019): 92. http://dx.doi.org/10.3390/jmmp3040092.
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In the drive towards a sustainable bio-economy, a growing interest exists in the development of composite materials using renewable natural resources. This paper explores the life cycle assessment of processing of Flax fibre reinforced polylactic acid (PLA), with a comparison of glass fibre triaxial fabric in the production process. The use of hydrocarbon fossil resources and synthetic fibres, such as glass and carbon, have caused severe environmental impacts in their entire life cycles. Whereas, Flax/PLA is one of the cornerstones for the sustainable economic growth of natural fibre composites. In this study, the manufacturing processes for the production of Flax/PLA tape and triaxial glass fibre were evaluated through a gate-to-gate life cycle assessment (LCA). The assessment was based on an input-output model to estimate energy demand and environmental impacts. The quality of the natural hybrid composite produced and cost-effectiveness of their LCA was dependent on their roving processing speeds and temperature applied to both the Flax/PLA tape and triaxial glass fabrics during processing. The optimum processing condition was found to be at a maximum of 4 m/min at a constant temperature of 170 °C. In contrast, the optimum for normal triaxial glass fibre production was at a slower speed of 1 m/min using a roving glass fibre laminating machine. The results showed that when the Flax and PLA were combined to produce new composite material in the form of a flax/PLA tape, energy consumption was 0.25 MJ/kg, which is lower than the 0.8 MJ/kg used for glass fibre fabric process. Flax/PLA tape and glass fibre fabric composites have a carbon footprint equivalent to 0.036 kg CO2 and 0.11 kg CO2, respectively, under the same manufacturing conditions. These are within the technical requirements in the composites industry. The manufacturing process adopted to transform Flax/PLA into a similar tape composite was considerably quicker than that of woven glass fibre fabric for composite tape. This work elucidated the relationship of the energy consumptions of the two materials processes by using a standard LCA analytical methodology. The outcomes supported an alternative option for replacement of some conventional composite materials for the automotive industry. Most importantly, the natural fibre composite production is shown to result in an economic benefit and reduced environmental impact.
4
Bledzki, Andrzej Korneliusz, Marta Lucka, Abdullah Al Mamun und Janusz Michalski. „Biological and electrical resistance of acetylated flax fibre reinforced polypropylene composites“. BioResources 4, Nr. 1 (20.11.2008): 111–25. http://dx.doi.org/10.15376/biores.4.1.111-125.
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Flax fibre reinforced polypropylene composites were fabricated using a high speed mixer followed by injection moulding. Prior to composite production, the fibre was modified by acetylation in the presence of perchloric acid. The effect of acetylation of the fibre was assessed on the basis of moisture resistance and dielectric properties of the resulting composites. It was found that the moisture absorption and swelling properties of the composites were reduced respectively to 60% and 30% due to acetylation. Two different types of biocide were mixed with untreated flax fibre, and the samples were exposed to decay fungi for up to 3 months along with control polypropylene. The composites with acetylated fibres showed good protection against fungi, and biocide had less effect on biological resistance. The dielectric properties of the flax-polypropylene composites were also estimated as a function of aging period. The composites with modified fibre showed more improvement in dielectric properties compared to the composites with untreated fibres. The mechanical properties were investigated for those composites. Tensile and flexural strengths of composites were found to be increased following acetylation due to modification, and strength properties of both untreated and acetylated flax fibre reinforced polypropylene composites decreased with respect to aging period. The Charpy impact strengths of composites were found to increase with increasing aging periods.
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Irvine, R. B., J. McConnell, G. P. Lafond, W. E. May, G. Hultgreen, A. Ulrich, K. Stonehouse, S. Chalmers und F. C. Stevenson. „Impact of production practices on fiber yield of oilseed flax under Canadian prairie conditions“. Canadian Journal of Plant Science 90, Nr. 1 (01.01.2010): 61–70. http://dx.doi.org/10.4141/cjps08233.
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Flax (Linum usitatissimum L.) cultivars commonly grown in western Canada have been developed primarily for seed production. These cultivars tend to be shorter, have lower fibre content, and have lower above-ground biomass than cultivars developed specifically for fibre production. Linseed production is the dominant flax product in western Canada and fibre is a co-product of oilseed production. The objectives of these studies were to evaluate the effects of northern European fibre flax production practices under western Canadian soil and climatic conditions. A number of cultivars in narrow band and solid-seeded planting geometries to determine if they had similar responses. When flax was planted at recommended seeding rates for linseed production, seed and fibre yields were not affected by planting geometry. Increasing the seeding rate from 40 to 120 kg ha-1 did not affect seed yield regardless of location or seeding date. Even though fibre content was not affected by seeding rate, higher seeding rates increased stem numbers, decreased stem size, reduced the variability in stem size and increased fibre yield. Delaying planting until the end of May increased fibre yields by an average of 35% with no corresponding decrease in seed yield. Since the relative seed and fibre yield responses of a wide range of cultivars were similar with solid seed and narrow band planting geometries, plant breeders can effectively select for higher fibre producing lines using narrow band seed openers using row spacings up to 30 cm apart. Key words: Linseed, row spacing, seeding rate, cultivar, fibre, fibre
6
Bolton, James. „The Potential of Plant Fibres as Crops for Industrial Use“. Outlook on Agriculture 24, Nr. 2 (Juni 1995): 85–89. http://dx.doi.org/10.1177/003072709502400204.
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At some time in the future, fibres produced on agricultural land will contribute significantly to the world fibre supply. Such fibres might come from residues or from dedicated fibre crops harvested annually. Dedicated fibre crops will become a reality sooner if agriculture can produce fibres more competitively than forestry. New markets for plant fibre may also help the farmer. Long-fibre crops (flax, hemp, kenaf) have particular promise providing that production costs are competitive with those for Third World fibres, or that a technological edge in processing can be established.
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Horne, M. R. L., D. Waldron, J. L. Harwood und R. J. Harwood. „The Production and Extraction of Flax-Fibre for Textile Fibres“. Journal of Biobased Materials and Bioenergy 4, Nr. 2 (01.06.2010): 98–105. http://dx.doi.org/10.1166/jbmb.2010.1073.
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8
Möhl, Claudia, Timo Weimer, Metin Caliskan, Tom Hager, Stephan Baz, Hans-Jürgen Bauder, Thomas Stegmaier, Werner Wunderlich und Götz T. Gresser. „Flax Fibre Yarn Coated with Lignin from Renewable Sources for Composites“. Polymers 14, Nr. 19 (27.09.2022): 4060. http://dx.doi.org/10.3390/polym14194060.
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The present experimental work analyses the potential of lignin as a matrix for materials made from renewable resources for composite components and the production of hybrid semi-finished products by coating a flax fibre yarn. Natural fibres, due to their low density, in combination with lignin can be a new renewable source for lightweight products. For this purpose, the extrusion process was adapted to lignin as a matrix material for bio-based composites and coating of natural fibre yarns. A commercial flax yarn is the basis for the lignin coating by extrusion. Subsequently, the coated flax yarn was characterised with regard to selected yarn properties. In order to produce composite plates, the lignin-coated flax yarn was used as warp yarn in a bidirectional fabric due to its insufficient flexibility transversely to the yarn axis. The commercial flax yarn was used as weft yarn to increase the fibre volume content. The tensile and flexural properties of the bio-based composite material were determined. There was a significant difference in the mechanical properties between the warp and weft directions. The results show that lignin can be used as matrix material for bio-based natural fibre composites and the coating of natural fibre yarns is an alternative to spun hybrid yarns.
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Graupner, Nina, Karl-Heinz Lehmann, David E. Weber, Hans-Willi Hilgers, Erik G. Bell, Isabel Walenta, Luisa Berger et al. „Novel Low-Twist Bast Fibre Yarns from Flax Tow for High-Performance Composite Applications“. Materials 14, Nr. 1 (29.12.2020): 105. http://dx.doi.org/10.3390/ma14010105.
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The use of natural fibres for components subjected to higher mechanical requirements tends to be limited by the high price of high-quality semi-finished products. Therefore, the present study deals with the development of more cost-effective staple fibre yarns made from flax tow. In the subsequent processing stage, the yarns were processed into quasi-unidirectional (UD) fabrics. The results of the fibre characterisation along the process chain have shown that no significant mechanical fibre damage occurs after slivers’ production. Fibres prepared from yarns and fabrics show comparable characteristics. The yarns were processed to composites by pultrusion to verify the reinforcement effect. The mechanical properties were comparable to those of composites made from a high-quality UD flax roving. The fabrics were industrially processed into composite laminates using a vacuum infusion and an autoclave injection process (vacuum injection method in an autoclave). While impact strength compared to a reference laminate based on the UD flax roving was achieved, tensile and flexural properties were not reached. An analysis showed that the staple fibre yarns in the fabric show an undulation, leading to a reorientation of the fibres and lower characteristic values, which show 86–92% of the laminate made from the flax roving. Hybrid laminates with outer glass and inner flax layers were manufactured for the intended development of a leaf spring for the bogie of a narrow-gauge railroad as a demonstrator. The hybrid composites display excellent mechanical properties and showed clear advantages over a pure glass fibre-reinforced composite in lightweight construction potential, particularly flexural stiffness.
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Kwiatkowska, Edyta, Małgorzata Zimniewska, Patrycja Przybylska und Barbara Romanowska. „Effect of Drought Stress on Quality of Flax Fibres“. Materials 16, Nr. 10 (15.05.2023): 3752. http://dx.doi.org/10.3390/ma16103752.
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Global warming has led to a change in climatic conditions. Since 2006, drought has contributed to a reduction of food production and other agriculture-based products in many countries. The accumulation of greenhouse gases in the atmosphere has caused some changes in the composition of fruits and vegetables, making them less nutritious. To analyse this situation, a study was conducted on the effect of drought on the quality of fibres provided by the main fibre crops in Europe, namely flax (Linum usitatissimum). The experiment consisted of growing flax under controlled comparative conditions with designed different irrigation levels, such as 25%, 35% and 45% field soil moisture. Three varieties of flax were grown in 2019, 2020 and 2021 in the greenhouses of the Institute of Natural Fibres and Medicinal Plants in Poland. Fibre parameters, such as linear density, length and strength, were evaluated according to relevant standards. In addition, scanning electron microscope images of the cross-section and longitudinal view of the fibres were analysed. The results of the study indicated that deficiency of water during the flax growing season resulted in lowering of fibre linear density and tenacity.
Dissertationen zum Thema "Flax fibre production"
1
Couture, Scott J. „Agronomic aspects of fibre flax : production in Québec“. Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp03/MQ50742.pdf.
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2
Sharma, H. S. S. „Bioprocessing of plant materials for production of flax fibre & mushroom compost“. Thesis, Queen's University Belfast, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273148.
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3
Reda, Ali. „A multiscale mechanical study of flax stems and fibres for the development of an in-the-field tool capable of predicting optimum retting“. Electronic Thesis or Diss., Université de Lille (2022-....), 2023. http://www.theses.fr/2023ULILN055.
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L'agriculture 4.0 se développe actuellement rapidement en termes de recherche, de développement et d'applications commerciales. L'objectif de l'agriculture 4.0 est d'utiliser la technologie pour améliorer tous les domaines de l'agriculture. L'agriculture 4.0 est tellement vaste que si l'on veut y contribuer, il faut choisir un domaine spécifique. Le domaine choisi pour l'étude de ce doctorat est la production de fibres de lin. Les fibres de lin sont des fibres naturellement solides qui peuvent être extraites des tiges de lin. Les tiges de lin ont évolué pour avoir des fibres robustes d'un diamètre de l'ordre du micromètre qui courent le long de l'extérieur de la tige et sont maintenues en place dans le tissu externe de la tige. Une fois extraites et isolées, les fibres de lin ont de nombreuses applications, allant des textiles aux matériaux composites. Afin de faciliter l'extraction mécanique des fibres de lin de leurs tiges mères, les tiges subissent un processus connu sous le nom de « rouissage ». Le rouissage entraîne la décomposition du tissu externe (appelé lamelle moyenne) entre les fibres. Une forme courante de rouissage est connue sous le nom de « rouissage de rosée ». Dans le rouissage de la rosée, des processus naturels tels que les bactéries et les champignons produisent des enzymes qui décomposent la lamelle centrale et séparent progressivement les grappes de fibres et les fibres des grappes. La durée du rouissage dépend fortement des conditions météorologiques. Un rouissage insuffisant entraîne une extraction difficile des fibres dans l'usine, tandis qu'un rouissage excessif peut compromettre la qualité des fibres. On sait depuis longtemps qu'il existe un point de rouissage optimal - même les anciens le savaient. Certains agriculteurs artisans qualifiés sont capables de juger ce point par une combinaison de manipulation manuelle des tiges, d'observation des dommages causés aux tissus externes par cette manœuvre, et aussi d'observation de la couleur et de l'odeur des tiges au cours de ce test très habile, mais artisanal. Il est clair que l'artisan effectue des tests de laboratoire rudimentaires littéralement « sur le terrain ». Il semblerait donc logique d'essayer de quantifier ces tests et de voir si un outil fiable peut être mis au point pour aider l'artisan. Et c'est exactement ce que d'autres ont tenté de faire. L'introduction de la thèse donne des exemples de tentatives de fabrication d'outils de rouissage optimal dans les années 1980 et suivantes. Inspirés par ces premiers travaux, les travaux de cette thèse tentent une caractérisation mécanique multi-échelle complète des tiges et des fibres de lin pendant un cycle de rouissage (été 2022) et, de manière quelque peu ambitieuse, réalisée en temps réel - à notre connaissance pour la première fois. La caractérisation mécanique comprend des essais mécaniques macroscopiques (flexion, écrasement et torsion de la tige), ainsi que des essais mécaniques microscopiques inédits sur des fibres de lin individuelles à l'aide de nouvelles méthodes inspirées des MEMS. En outre, les propriétés mécaniques nanoscopiques de la paroi cellulaire primaire des fibres de lin en cours de rouissage ont été caractérisées à l'aide de l'AFM par nanoindentation. Au fur et à mesure que le travail expérimental, l'analyse via la modélisation analytique et l'interprétation descendent en échelle, de la macro au nano en passant par le micro, nous en apprenons un peu plus sur la manière dont le rouissage affecte les tiges, leurs propriétés et leurs fibres. En plus de l'apprentissage, un résultat très positif du doctorat est que l'on est capable de suggérer un mécanisme de dommage induit mécaniquement dans les tiges, qui pourrait être la base d'un outil. On peut cependant noter que la nature multiparamétrique incontrôlable du sujet, par exemple le temps, signifie que plusieurs études seraient nécessaires pour confirmer sans aucun doute les observations d'un seul cycle de rouissageAgriculture 4.0, also known under several aliases such as ‘digital agriculture', ‘smart farming', and ‘e-farming' is currently developing rapidly in terms of research, development, and commercial applications. As with Agriculture 1.0, 2.0, and 3.0, the objective of Agriculture 4.0 is the use of technology to improve all areas of agriculture. In Agriculture 4.0 it is the application of microelectronics and microtechnologies. Unlike before, these technologies bring things such as the internet-of-things, big data, telecommunications, novel sensing, rapid feedback, data analysis, connectivity, artificial intelligence etc. In principle, all these areas should result in a massive modernization of farming in terms of organisation, yield, efficiency, and quality of produce. However, Agriculture 4.0 is so vast that if one is to contribute to it, even in a minor way, one has to choose a specific area to contribute. The area chosen for the study in this PhD was flax fibre production. Flax fibres are naturally strong fibres which can be extracted from flax stems. The flax stems have evolved to have robust micrometre-diameter fibres running the length of the outside of the stem, and held in place in the external tissue of the stem. Once extracted and isolated, flax fibres have numerous applications ranging from textiles to composite materials. In order to facilitate the mechanical extraction of flax fibres from their parent stems, the stems undergo a process known as ‘retting'. Retting leads to the breakdown of the external tissue between the fibres. A common form of retting is known as ‘dew retting'. In dew retting, natural processes such as bacteria and fungi result in enzymes which break down the middle lamella and gradually separate fibre bunches and fibres from bunches. The length of dew retting depends heavily on the weather. Too little retting results in difficult fibre extraction in the factory, too much retting can result in a compromise in fibre quality. It has long been known that there is an optimum retting point-even the ancients knew this. Certain skilled artisan farmers are able to judge this point via a combination of manual manipulation of the stems, observation of damage caused to the external tissue via this manoeuvre, and also observing the colour and the smell of the stems during this very skilled, but artisanal, testing. It is clear that the artisan is performing rudimentary laboratory tests quite literally ‘in-the-field'. It would seem logical therefore to try to quantify such tests and see if a reliable tool can be made to help the artisan. And indeed, this is exactly what others have attempted. The introduction of the PhD gives examples of attempts to make optimal-retting tools in the 1980s and after. Inspired by this early work, the work of this PhD attempts a full multiscale mechanical characterization of flax stems and fibres during a retting cycle (summer 2022) and, somewhat ambitiously, performed in real time-to our knowledge for the first time. The mechanical characterization involved macroscopic mechanical tests (bending, crushing, and twisting), as well as novel microscopic mechanical testing of single flax fibres using novel methods inspired by MEMS. In addition, the nanoscopic mechanical properties of the primary cell wall of retting flax fibres was characterised using nanoindentation AFM. As the experimental work, analysis via analytical modelling, and interpretation descends in scale from macro, through micro, to nano, we learn a little more of how the retting affects the stems, their properties, and their fibres. In addition to simply learning, a very positive outcome of the PhD is that one is able to suggest a mechanically-induced damage mechanism in stems which could be the basis for a tool. One can note however, that the uncontrollable multiparameter nature of the subject, e.g. the weather, means that several studies would be needed to confirm beyond doubt observations from a single retting cycle
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„Elucidating the genetic basis of bast fibre production in flax (Linum usitatissimum L.)“. Thesis, 2012. http://hdl.handle.net/10388/ETD-2012-03-365.
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Flax is often considered a total utilization crop because of the potential to extract value from two distinct products - seeds and stem fibres. However, very little genetic information is available on flax fibre genetics in comparison to oil improvement studies. In order to gain a detailed understanding of genetic control of the fibre concentration and search for the possibilities of developing dual purpose flax lines using both seed oil and stem fibre, the following studies were initiated:
The first study evaluated the fibre and oil-related traits in a recombinant inbred population derived from a cross between a fibre flax variety Viking and an oilseed flax genotype E1747 over multiple locations under western Canadian field conditions. The study confirmed the presence of a significant genotype by environment interaction (p < 0.01) for fibre concentration indicating selection for this trait will be challenging. However, a lack of significant correlation between fibre and oilseed characteristics in field trials was encouraging and strengthened the hypothesis that breeding dual purpose flax types for western Canada is possible. The study also identified potential recombinant inbred lines (RILs) with enhanced fibre concentration as well as oil characteristics for use in future breeding endeavors.
The second study established an anatomical basis for further research into flax fibre improvement by studying differences between the stem anatomy of 14 diverse flax genotypes in the field and under controlled environments such as a growth chamber. The results from the study supported the use of controlled environments for the purpose of quick screening of high fibre containing genotypes, especially at the green capsule stage of plant growth. The results also indicated that it was possible to select high fibre oilseed flax lines based on anatomical markers such as average area of single fibre cells, total fibre area and fibre to stem area ratio.
In the third study, 17 simple sequence repeat (SSR) and 2 cleaved amplified polymorphic sequences (CAPS) molecular markers were used to assess the extent of genetic variability in the Viking × E1747 RIL population. CAPS markers LuFAD3A and LuFAD3B had the highest marker trait association (p < 0.0001) with linoleic and linolenic acid concentration. SSR markers such as CV8824, 5B6 and LU32 were found to be associated with plant height, oil concentration and protein concentration respectively using single marker analysis and step wise regression analysis. The molecular study confirmed the importance of Viking × E1747 mapping population in identifying genes/ markers related to both fibre and oilseed related traits in flax.
In the fourth study, global transcript profiling using cDNA - based microarrays was performed to identify differentially expressed fibre related transcripts between Viking and E1747. The largest group of transcripts (7 %) found more abundant in Viking relative to E1747 fell under the functional group of cell wall development using gene ontology (GO) analysis. Transcripts such as callose synthases, expansins, cytochrome P450, fasciclin-like arabino galactan proteins and β-galactosidases were highly abundant in Viking relative to E1747. The transcripts more abundant in E1747 relative to Viking were UDP – glucose glucosyltransferase, auxin repressed protein, ubiquitin conjugating enzyme, peroxidases and lipid transfer proteins. Quantitative real time PCR results confirmed the suitability of the microarray platform to accurately discriminate transcript profiles between the two diverse flax types.
In conclusion, this research has provided a number of new insights into flax fibre genetics. This information lays the foundation for further genetic studies on flax bast fibres and will complement research on developing dual purpose flax varieties.
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Lisson, S. „An integrated assessment of hemp (Cannabis sativa L.) and flax (Linum usitatissimum L.) as sources of fibre for newsprint production“. Thesis, 1997. https://eprints.utas.edu.au/20414/1/whole_LissonShaun1998_thesis.pdf.
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The primary objective of the study reported in this thesis was to show whether fibre
of value as a reinforcing agent in newsprint production could be produced
economically from hemp and flax grown in Tasmania. This involved an integrated
analysis of the whole potential industry, with studies into the key areas of crop
production, pulp and paper manufacture and economic viability. Another objective
of the study was to develop a computer model for simulating the growth,
development and yield of hemp in response to climatic, soil and management
inputs. This would enable the results of this project to be extrapolated to other
suitable production areas and hence assist in the initial assessment of cropping
potential and the identification of optimum site and management conditions. Of the nine hemp cultivars that were assessed, Kompolti and Futura 77 were the
best performing, producing crops in excess of 2 m high and yielding up to
1500 g/m2of oven dry stem. The results from sowing date trials suggest that
September is the optimum month for sowing hemp in Tasmania. Later sowings
resulted in a reduction in stem yield associated with a shortening of the thermal
time duration from sowing to flowering. Furthermore, van der Werf etal. (1996)
reported yield declines from later sowings due to delays in canopy closure and a
subsequent reduction in intercepted radiation. Sowings prior to September appear
to be limited by premature flowering in response to short daylengths. In an
irrigation trial conducted in north west Tasmania, significant stem yield differences
were not apparent for irrigation regimes based on refill to field capacity at deficits
down to 120 mm. Maximum bark yield was obtained from regimes based on a
60 mm deficit or less (water consumption of 535 mm). The stem yields under
rainfed conditions were substantially below those of the irrigated treatments. Stem
yield responded in a parabolic manner to plant densities ranging from 50 to
300 plants/m2, with maximum yields at about 110 plants/m 2.
The results from a flax cultivar trial showed that stem yields of selected European
cultivars were superior to a number of older Australian cultivars, developed for the
Australian flax industry during the mid 1900's. The cultivar Ariane was selected for
further field trials and produced crops with oven dry stem yields of up to 1000 g/m 2.
Field studies with a range of sowing date and irrigation treatments demonstrated
that flax could be sown from autumn through to spring, under either rainfed or
irrigated conditions. Maximum stem and seed yields were from an autumn sowing
with supplementary irrigation from flowering to late grain fill. The optimum seeding rate for autumn sown flax was found to involve a compromise between maximising
yield and minimising the potential losses from lodging apparent at densities in
excess of about 1000 plants/m2. Lodging was not a major problem at the optimum
seeding rates for spring sowings of flax.
Controlled environment studies were conducted into the response of pre-emergent
development to temperature, and the flowering response of selected hemp
cultivars to photoperiod. Parameters, constants and functions derived from these
studies, the field trials and from selected references, were then used to develop a
hemp simulation model. The model adequately predicted phenology, leaf area and
biomass production for cv. Kompolti grown in north west Tasmania.
The Australian newsprint industry currently uses a mixture of locally sourced
eucalypt, radiata pine and recycled paper pulps, blended with an imported kraft
(chemical) pulp. The purpose of the kraft pulp is to reinforce the newsprint. The
primary aim of the pulping trials conducted in this study was to investigate the
potential of using flax and hemp bark and whole stem pulps as alternative
reinforcing agents in newsprint production. The existing cold caustic soda (CCS)
and thermomechanical (TMP) processes were trialled with a view to harnessing the
existing infrastructure and expertise. Cold caustic soda pulp made from the bark
fraction formed paper of very high tear index, but with lower tensile index and
tensile energy absorption than would be desirable from softwood kraft. This
limitation might be overcome by using a higher proportion of non-wood pulp in the
overall newsprint blend or through breeding improvements. The use of pulping (&
pre-pulping) equipment more suited to non-woods may overcome handling
difficulties associated with excessive fibre length. Pulps were also made from the core fraction to assess its suitability as a
supplement to the short fibred component of the existing newsprint blend. Whilst
potentially suited for use as a short fibred supplement in newsprint manufacture,
the properties of the core pulps are not currently in demand within the industry.
Interest from the newsprint industry in taking the financial risk of adopting hemp
and flax based pulps as an alternative to kraft, would require that the total cost be
somewhat less than the imported option. Similarly, interest from primary producers requires that the gross returns from these crops are at least comparable with a
range of crop alternatives. The minimum bark price (mill gate) that is likely to attract
farmers would vary between flax and hemp and between growing conditions. Dual
purpose flax grown under dryland conditions would require a separated bark price
in the vicinity of $400/t to $450/t. Irrigated hemp and flax crops grown in the more
productive north west area of the state would require a price in excess of about
$650/t. These minimum bark prices are not attractive to the newsprint industry at
present. Future financial viability will depend on a number of factors, including:
fibre yield and quality (eg bark proportion in the stem and fibre tensile strength
properties) improvements, elevated kraft pulp prices, and the establishment of
strong markets for the stem core fraction and the seed of flax.
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Pikwa, Kumnandi. „Development and evaluation of flux enhancement and cleaning strategies of woven fibre microfiltration membranes for raw water treatment in drinking water production“. Thesis, 2015. http://hdl.handle.net/10321/1398.
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Thesis submitted in fulfillment of the academic requirement for the degree of (M.Tech.: Chemical Engineering), Durban University of Technology, South Africa, Durban, 2015.Woven Fibre Microfiltration (WFMF) membranes have several advantages over its competitors with respect to durability, making it a favourable alternative for the developing world and operation during rough conditions. Wide application of membrane technology has been limited by membrane fouling. The durability of the WFMF membrane allows more options for flux enhancement and cleaning methods that can be used with the membranes even if they are vigorous. Therefore, the purpose of this work was to develop and evaluate flux enhancement and cleaning strategies for WFMF membranes. Feed samples with high contents of organics and turbidity were required for the study. Based on this, two rivers which are Umkomaasi and Duzi River were identified to satisfy these criteria. A synthetic feed with similar fouling characteristics as the two river water was prepared and used for this study. The synthetic feed solution was made up of 2 g/ℓ of river clay in tap water and 0.5% domestic sewerage was added into the solution accounting for 2% of the total volume. A membrane filtration unit was used for this study. The unit consisted of a pack of five membrane modules which were fully immersed into a 100 litres filtration tank. The system was operated under gravity and the level in the filtration tank was kept constant by a level float. The study focused on evaluating the performance of the woven fibre membrane filtration unit with respect to its fouling propensity to different feed samples. It also evaluated and developed flux enhancement and cleaning strategies and flux restoration after fouling. The results were compared to a base case for flux enhancement and pure water fluxes for cleaning. The WFMF membrane was found to be prone to both internal and external fouling when used in the treatment of raw water (synthetic feed). Internal fouling was found to occur quickly in the first few minutes of filtration and it was the major contributor for the loss of flux from the WFMF membrane. The fouling mechanism responsible for internal fouling was found to be largely pore blocking and pore narrowing due to particle adsorption on/in the membrane pores. The structure (pore size, material and surface layout) of the WFMF membrane was found to be the main cause that made it prone to internal fouling. The IV major fouling of the WFMF membrane was due to internal fouling, a high aeration rate of 30 ℓ/min had minimal effect on the fouling reduction. An aeration rate of 30 ℓ/min improved the average flux by only 36%, where a combination of intermittent backwashing with brushing and intermittent backwashing with aeration (aeration during backwashing only) improved average flux by 187% and 135% respectively. Pre-coating the WFMF membrane with lime reduced the effects of pore plugging and particle adsorption on the membrane and improved the average flux by 66%. The cleaning strategies that were most successful in pure water flux (PWF) recovery were high pressure cleaning and a combination of soaking and brushing the membrane in a 0.1% NaOCl (desired) solution. PWF recovery by these two methods was 97% and 95% respectively. Based on these findings, it was concluded that the WFMF membrane is susceptible to pore plugging by colloidal material and adsorption/attachment by microbiological contaminants which took effect in the first hour of filtration. This led to a 50% loss in flux. Also, a single flux enhancement strategy proved insufficient to maintain a high flux successfully. Therefore, combined flux enhancement strategies yielded the best results.
Bücher zum Thema "Flax fibre production"
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L, Easson D., und Great Britain, Hrsg. Flax for fibre: A guide to flax production and pre-harvest retting : short term booklet. 3. Aufl. [Hillsborough]: Department of Agriculture, Northern Ireland, 1985.
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1
Michelena, Aitor Hernandez, Jasper Graham-Jones, John Summerscales und Wayne Hall. „Eco-friendly Flax Fibre/Epoxy Resin/Composite System for Surfboard Production“. In RILEM Bookseries, 267–77. Dordrecht: Springer Netherlands, 2016. http://dx.doi.org/10.1007/978-94-017-7515-1_20.
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Sherman, John, Jonathon Maloy, Emidio Martino, Patrice Cusatis und Paul Fasano. „Use of Thickened High Water Hydraulic Fluid in Flat Rolled Steel Production“. In Fire Resistant Fluids, 1–23. 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959: ASTM International, 2014. http://dx.doi.org/10.1520/stp157320130179.
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Schlag, Mareike, Kai Brune, Hauke Brüning, Michael Noeske, Célian Cherrier, Tobias Hanning, Julius Drosten et al. „Extended Non-destructive Testing for Surface Quality Assessment“. In Adhesive Bonding of Aircraft Composite Structures, 119–222. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-319-92810-4_3.
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AbstractThis chapter introduces various extended non-destructive testing (ENDT) techniques for surface quality assessment, which are first characterized, then enhanced, and finally applied to assess the level of pre-bond contaminations intentionally applied to carbon fiber reinforced plastic (CFRP) adherends following the procedures described in the previous chapter. Based on two user cases comprising different scenarios that are characteristic of either aeronautical production or repair, the detailed tests conducted on two types of sample geometry, namely flat coupons and scarfed pilot samples with a more complex shape, form the basis for applying the advanced ENDT procedures for the monitoring of realistic and real aircraft parts, as will be described in Chap. 10.1007/978-3-319-92810-4_5. Specifically, the reported investigations were performed to assess the surface quality of first ground and then intentionally contaminated CFRP surfaces using the following ENDT tools: the aerosol wetting test (AWT), optically stimulated electron emission (OSEE), two differently implemented approaches based on electronic noses, laser-induced breakdown spectroscopy (LIBS), Fourier-transform infrared (FTIR) spectroscopy, laser-induced fluorescence (LIF), and laser vibrometry.
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„Chapter 3. Flax and Wool: Fiber Production and Processing“. In The Weaver's Craft, 40–66. University of Pennsylvania Press, 2003. http://dx.doi.org/10.9783/9780812203240-005.
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Kolodziejczyk, P., L. Ozimek und J. Kozłowska. „The application of flax and hemp seeds in food, animal feed and cosmetics production“. In Handbook of Natural Fibres, 329–66. Elsevier, 2012. http://dx.doi.org/10.1533/9780857095510.2.329.
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Karg, Sabine. „Neolithic flax production in the pre-Alpine region – knowledge increase since the 19th century“. In The Competition of Fibres, 141–52. Oxbow Books, 2020. http://dx.doi.org/10.2307/j.ctv13pk7d6.19.
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Song, P. A., Y. Zhang und X. Wen. „Introduction“. In Green Fire Retardants for Polymeric Materials, 1–3. Royal Society of Chemistry, 2023. http://dx.doi.org/10.1039/bk9781839169793-00001.
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Polymeric materials including natural and synthesised ones have been ubiquitously used in every corner of modern society because of their good chemical resistance, high specific strength, and excellent flaw tolerance. However, their organic composition and aliphatic chains make most of them highly flammable, which significantly restricts their real-world applications in industrial settings. For this reason, a variety of fire retardants (FRs) have been successfully developed to endow polymers with desired fire retardancy to meet the fire-retardant requirements in industry. Traditional fire retardants, such as halogenated FRs and organophosphate esters, can be harmful to our ecosystems and human and animal health despite their high efficiency in polymers. In addition, the production of fire retardants often involves the use of a large volume of organic solvents, which generates associated issues, such as the treatment of waste organic solvents. This has greatly catalyzed the development of green fire retardants and the green synthesis of fire retardants for polymeric materials to contribute to the creation of a sustainable society.
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İsmail Tosun, Yıldırım. „Microwaved Flux Matter- Char Sand Production of Waste Coal Char/Biochar/Gypsium Ash and Fly Ash Mixtures for Mortar- Fire Retardent Composite“. In Biochar - Productive Technologies, Properties and Application [Working Title]. IntechOpen, 2022. http://dx.doi.org/10.5772/intechopen.101559.
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Fire inhibiting materials as cement filler are used in mortar constructions especially using gypsium board, similar isolator mortars. The mortar covered char and ash sand mixtures insulate heat and reduce fire blazing activity. Ytong, or porous briquettes and clay is the world’s most popular insulating construction material retarding blaze due to its porous durability, processability, and cost. However, producing concrete or mortar with high isolation with HD styrene panels is insulating the structure, protecting the cement board against flammable fire risk. Slag-type masonry requires high heavier fire inhibiting matter in construction. Styrene type isolation provides fire inhibiting at lightweight masonry or mortar generation with the use of waste gypsium fines and waste coal slimes and high ash char “char sands” and ash fines. The growing environmental concerns motivated researchers to search for char waste slag-type inhibiting materials using gypsium fines and biomass waste char fines leading to alternative routes of fire-retardant mortar construction. In this way, several alternative materials of isolation mortar have prompted.
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Martinka, Jozef, und Janka Dibdiakova. „Materials for Safety and Security“. In Safety and Security Issues in Technical Infrastructures, 288–320. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-3059-7.ch011.
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This chapter deals with materials used in safety and security engineering. The most commonly used materials in this field include shielding materials, materials for protective suits, electrically insulating materials and materials for fire protection. The first part of the chapter describes the properties of materials used in the above applications. The second part of the chapter focuses on characteristics of materials that accurately describe their fire risk. The fire risk of a material is quantified by its resistance to ignition (determined generally by critical heat flux and ignition temperature) and by the impact of the fire on the environment. The impact of fire is usually determined by the heat release rate, toxicity of combustion products (primarily determined by carbon monoxide yield and for materials that contain nitrogen, also through the hydrogen cyanide yield) and the decrease of visibility in the area (depending on the geometry of the area and the smoke production rate).
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Muniraj, Navya, Weixuan Gong, Muthu Kumaran Selvaraj und Albert Simeoni. „A study of fire and plume dynamics for static pool fires and their interaction with vegetation“. In Advances in Forest Fire Research 2022, 1566–71. Imprensa da Universidade de Coimbra, 2022. http://dx.doi.org/10.14195/978-989-26-2298-9_238.
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Prescribed burns are an essential tool of fire management to reduce the impact and occurrence of wildfires. While managing prescribed burns, the smoke trajectory and downwind exposure to smoke are intimately coupled with the smoke production dynamics and the development of the fire plume in the vicinity of the fire front. In turn, the fire plume development is strongly coupled to fire behavior and the flow environment near the fire. This work aims at understanding fire behavior and plume development while interacting with vegetation at the large laboratory scale through experiments and modeling. In order to investigate these coupled processes, initially, flame and plume behavior from a static fire source will be characterized. A rectangular pool fire fueled by diesel is used and point measurements of flow, temperature and heat flux will be conducted. The burning rate will be measured using a load cell. K-type thermocouples and bi-directional pressure probes will be used for measuring the temperature and velocity, respectively in the flame and plume zones. These data will be used for validating a numerical model for simulating pool fires and the model will be subsequently used for predicting the plume interaction with vegetation. A Douglas fir tree, whose properties are well defined in the literature, will be used as vegetation. The Lagrangian particle model available in the Fire Dynamics Simulator (FDS) will be used to model the tree. The tree will be of regular shape and size with foliage and different classes of wood segregated based on typical size (diameter) range. The bulk density of the tree will be varied to replicate the systematic and controlled variation of the flow obstruction encountered by the plume and gives a realistic prediction of velocity, temperature, and heat flux within the vegetation. In the future, experiments with vegetation located in the plume region will be conducted to validate the numerical predictions.
Konferenzberichte zum Thema "Flax fibre production"
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Filer, Mark, Hacene Chaouch, Jonathan Chu, Raju Kankipati und Tom Issenhuth. „Transmission of Nyquist-shaped 32 GBaud PM-QPSK Over a Production Flex-grid Open Line System“. In Optical Fiber Communication Conference. Washington, D.C.: OSA, 2016. http://dx.doi.org/10.1364/ofc.2016.w4g.3.
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Strohrmann, Katharina, Nicolas André und Hajek Manfred. „Hybrid Natural Fiber Composites in a Helicopter Cabin Door - Mechanical Properties and Ecological Efficiency“. In Vertical Flight Society 75th Annual Forum & Technology Display. The Vertical Flight Society, 2019. http://dx.doi.org/10.4050/f-0075-2019-14721.
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The overall goal of this work is the application of bio-based materials in an aerospace structure, while maintaining the structural-mechanical performance in accordance with its certification standards. This goal was pursued through the use of hybrid composites made from a combination of conventional (carbon) and bio-based fiber composites (flax). The cockpit door of an ultralight helicopter was chosen to prove the applicability of this hybrid composite. A reference door, built from carbon-fiber-reinforced polymers, was considered a benchmark to the requirements in terms of mass, stiffness, damping, ecological efficiency and costs. First, the benchmark door was built and characterized. Then the geometry was redesigned for the application of flax f iber composites, leading to an increase of the areal moment of inertia. The new geometry was then analyzed using multiple gravity loads. Highly loaded areas were locally reinforced with carbon prepregs. Tensile tests and subcomponent cantilever beam tests were iteratively analyzed for the development and advancement of the finite element analysis (FEA) model. A significant material nonlinearity in form of a reduction of elasticity with increasing strains is inherent in flax-fiber composites, this phenomenon was interpreted as a yield point and included in the failure analysis. The resulting hybrid design showed promising results, as the stiffness matched the reference doors and a mass reduction of 6% with an increase in the bio-based material mass from 0 to 43% was achieved. But, due to manufacturing issues, additional epoxy layers had to be used in the flax weave, which significantly reduced the fiber volume content. As a result, the built hybrid door consisted of a bio-based mass of only 30%. The ecological efficiency, in terms of material primary production, of the hybrid door is significantly better than the reference doors. By calculation, the hybrid door’s materials consumed 221.7MJ-eq less energy, while emitting 11.0kgCO2-eq less carbon. However, drawbacks in the operational life due to an increased mass are inherent and break even on the ecological efficiency. This weight-drawback needs to be prevented, which could be achieved through a denser flax-fiber weave. In order to point out the potential of natural fibers, the designed hybrid version is also compared to the reference. Furthermore, benefits in terms of costs, vibration behavior, and mechanical damping are itemized in this work.
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Feng, Rui, Quanyi Liu, Runhe Tian, Kewei Chen, Rui Yang und Hui Zhang. „Solid Fuel Fire Behavior Under Fixed Pressure in a Low-Pressure Chamber“. In ASME 2015 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/imece2015-51441.
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To comprehensively reveal the difference of solid fuel fire characteristics at different altitudes, fire experiments of cardboard boxes at multiple static pressures with two configurations filled with shredded office paper were conducted in a low-pressure chamber. The measured parameters are mass burning rate, radiative heat flux, oxygen concentration and heat release rate (HRR) etc. The mass burning rate divided by fire base dimension ṁ/D is correlated against the production of pressure-squared times length-cubed (P2L3) to the power of 0.29 based on current cardboard boxes fire test data. HRR of two boxes fire tests are higher than that of one box fire tests under fixed pressures. However, there are a higher peak of HRR under a fixed higher pressure for one-box fire tests while a lower peak of HRR under a higher pressure for two-box fire tests. The HRR would decrease sharply after reaching the peak.
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SHCHEMELININ, YONI, JARED W. NELSON und ROBERTA AMENDOLA. „HYDRAULIC BULGE TESTING TO COMPARE FORMABILITY OF CONTINUOUS AND STRETCH BROKEN CARBON FIBER PREPREG LAMINATES“. In Thirty-sixth Technical Conference. Destech Publications, Inc., 2021. http://dx.doi.org/10.12783/asc36/35953.
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The use of carbon fiber reinforced polymer composites has increased with the increased need for high-strength, low-density materials, particularly in the aviation industry. Stretch broken carbon fiber (SBCF) is a form of carbon fiber created by the randomized breaking of aligned fibers in a tow at inherent flaw points, resulting in a material constituted of collimated fiber fragments longer than chopped fibers. While continuous carbon fibers possess desirable material properties, the limited formability prevents their wider adoption. SBCF composites exhibit pseudo-plastic deformation that can potentially enable the use of traditional metal forming techniques like stamping and press forming well established in mass production applications. To investigate the formability of SBCF composites prepared with either continuous or stretch broken Hexcel IM-7 12K fiber, impregnated with Huntsman RDM 2019-053 resin, hydraulic bulge testing was performed to explore the strain behavior under biaxial stress conditions at elevated temperature under atmospheric pressure. Initial results show better formability of SBCF compared to continuous fiber, characterized by the axisymmetric response to the applied stress.
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Wei, Zhiyong, Kok-Meng Lee, Zhi Zhou und Siu-Ping Hong. „Computational Model for Predicting the Location of Glass Solidification in Optic Fiber Drawing“. In ASME 2004 Heat Transfer/Fluids Engineering Summer Conference. ASMEDC, 2004. http://dx.doi.org/10.1115/ht-fed2004-56251.
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This paper presents a computational model for predicting the location at which the glass fiber solidifies during a high-speed drawing process. Although modeling of the optic fiber drawing process has been of interest for the past two decades, traditional fiber drawing process uses small diameter preforms and low draw speeds, where the glass usually solidifies and turns into fiber inside the furnace. Much larger preforms drawn at higher speeds have been used in the state-of-the-art fiber drawing systems to improve production efficiency and reduce cost. Insulated post-chambers are often added below the furnace to reduce the glass cooling rate so that the optical loss in the fiber is low. To provide a basis for design optimization of the post-chamber, we have solved the conjugate problem of the glass free surface flow and the air convection to determine the location where the glass solidifies. As radiation is the dominant mode of heat transfer in the glass, the radiative transfer equation (RTE) is solved directly by discrete ordinate method (DOM). The heat flux due to the mixed convection of the air is also numerically calculated along the glass free surface, which involves the boundary layer flow around a continuously moving fiber and the buoyancy driven flow through the open-ended channel. The calculated free shapes are compared against the experimentally measured data to verify the computational model.
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Choudhury, Tanzim Ahmed, George Mahley, Pinkesh Sanghani und Hans Kumar. „Advancements in CO2 Membrane Separation Technologies: Reducing Emissions and Enabling CCS“. In ADIPEC. SPE, 2022. http://dx.doi.org/10.2118/211191-ms.
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Abstract To overcome production restraints caused by CO2 and H2S in mature basins, operators require more cost-effective gas treatment to effectively remove these impurities from natural gas. Cellulose triacetate (CTA) based CO2 separation membranes have already been used extensively in acid gas treatment and associated enhanced oil recovery. A new technical challenge was to provide a horizontal membrane element that could easily replace poorly performing existing flat-sheet spiral-wound membranes with minimal operational changes to debottleneck existing hardware capacity, minimize hydrocarbon loss, and reduce membrane replacement frequency. Existing CTA vertical hollow fiber CO2 separation membranes were further developed and modified into the form of 8-in./8.25-in diameter horizontal packaging. Qualification testing was performed at an in-plant gas test loop using full-scale membrane elements. Test programs included varying inlet parameters such as feed gas pressure, temperature, and a wide range of CO2 concentrations. Results showed that the horizontal configuration of the hollow fiber gas separation membrane exhibited superior separation characteristics in terms of gas throughput and hydrocarbon retention in the sales gas, when compared to alternative currently available CO2 removal membrane technologies. The robustness of the membrane polymer was confirmed throughout several startup and shutdown scenarios, with stable gas flux and selectivity observed during rigorous and long-term testing. The membrane elements can be deployed in existing installations as a "drop-in" solution to overcome production constraints, whilst driving down the cost of excessive membrane replacements. In brownfields, more efficient acid gas removal and enhanced hydrocarbon recovery will reduce emissions by lowering gas flaring and limiting the potential release of methane. Upfront capital expenditure and ongoing operational expenses in greenfield projects can be significantly reduced by the greater natural gas treatment capacity per membrane compared to alternative membrane solutions. The high-purity CO2 permeate stream can also support the implementation of carbon capture and sequestration (CCS), thereby helping to reduce the assets carbon footprint and overall emissions. The advancements in horizontal CTA membranes have been proven in operation at several facilities, where they have improved the economics of the assets via reduced hydrocarbon flaring and increased gas throughput. An intelligent, automated digital membrane monitoring tool has been developed and deployed to further optimize membrane operations. Operators have also been able to actively pursue acid gas fields previously considered uneconomical for production. Such greenfield and brownfield case studies will be presented as part of this paper.
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Hashish, Mohamed. „A Study on AWJ Trimming of Composite Aircraft Stringers“. In ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-77361.
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A study was undertaken to develop AWJ processes and tools for trimming carbon fiber composite stringers used in several structural air frame components. The cutting strategy was to trim the stringers flanges from the inside out to allow beveling and to minimize cutting risks. Specially designed small size side fire cutting heads were developed to meet this requirement, and they were first used to cut flat composite material samples with thicknesses up to 1 inch. These cutting tests focused on identifying the cutting speeds for producing high quality surfaces without any frayed edges or delamination and meet the Boeing BAC 5578 specifications. For example, tests were performed to determine the effects of pressure, abrasive flow rate, orifice size, and cutting speed on the taper and surface finish of the produced surface walls. It was shown that cutting stringer material with AWJ is highly feasible both qualitatively and quantitatively. An example cutting rate of 18 inch/min was determined to cut 0.65-inch thick composite to produce better than 400 micro inch surface finish with less than 1 degree taper. Trimming tests were then performed for both 90 and 45 degrees to produce straight and beveled surfaces using sample stringers. This new AWJ process is now being used for production at aircraft subcontractor facilities for the Boeing 787.
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Graham, G. M., und M. K. Alam. „Study of a Wall Jet Burner for the Outside Vapor Deposition Process“. In ASME 1996 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1996. http://dx.doi.org/10.1115/imece1996-1042.
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Abstract An elongated wall jet burner for the production of optical fiber preforms using the outside vapor deposition process has been developed at Ohio University. The burner has been tested experimentally and has been found to produce a laminar flame jet at relatively large flow rates. The elongated design permits the deposition of SiO2 soot particles over a larger substrate area than for cylindrical burners. The burner has been tested in combination with a flat plate substrate to support concurrent numerical modeling efforts. The numerical model uses the commercial code FLUENT for computing the velocity and temperature fields and a second code developed at Ohio University for computing the particle deposition. Experimental data are used for velocity and temperature boundary conditions. Numerically computed deposition efficiencies correlate with experimental data.
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Hartz-Behrend, K., S. Kirner, J. Schein, D. P. Jonke, M. Englhart und J. Zierhut. „Control of Wire Arc Spraying Using Artificial Neural Networks for the Production of Thin-Walled Moulds for Carbon Fiber Reinforced Plastics“. In ITSC 2012, herausgegeben von R. S. Lima, A. Agarwal, M. M. Hyland, Y. C. Lau, C. J. Li, A. McDonald und F. L. Toma. ASM International, 2012. http://dx.doi.org/10.31399/asm.cp.itsc2012p0436.
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Abstract Traditionally, large moulds for manufacturing of CFRP (carbon fiber reinforced plastics) parts are machined from a solid metal block making this way of manufacturing very energy and time consuming. Using wire arc spraying thin-walled moulds can be produced by spraying onto an original mould and separating the coating. In order to create a reliable and high quality product the manufacturing process needs to be highly reproducible. Thus the spraying process requires monitoring and control, which can be done using artificial neural networks (ANN). In our approach, for monitoring the process the diagnostic system PFI (Particle Flux Imaging) is used to characterize the spray particle stream, which is essentially achieved by fitting an ellipse to an image of the particle stream. Comparing deviations from a reference ellipse recorded for an “optimal” coating process provides data that can subsequently be used for process control. Investigations performed by the method of design of experiments (DOE) show a very strong correlation of the parameters pressure, current, and voltage with certain parts of the PFI data: for example the semi-minor axis of the ellipse depends linearly on voltage and current but quadratic on pressure. These results can further on be used to control the coating process by ANN. This paper discusses the application of this method and its feasibility for industrial use.
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Calomino, Anthony, und M. Verrilli. „Ceramic Matrix Composite Vane Subelement Fabrication“. In ASME Turbo Expo 2004: Power for Land, Sea, and Air. ASMEDC, 2004. http://dx.doi.org/10.1115/gt2004-53974.
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Vane subelements were fabricated from a silicon carbide fiber reinforced silicon carbide matrix (SiC/SiC) composite and were coated with an environmental barrier coating (EBC). In order to address realistic critical design features of a turbine airfoil, the vane subelement cross section was derived from an existing production aircraft engine vane. A new fabrication technique has been developed at NASA Glenn Research Center that enables ceramic composite vanes to be constructed using stoichiometric SiC fiber in the form of a two dimensional cloth. A unique woven cloth configuration was used to provide a sharp trailing edge with continuous fiber reinforcement. Fabrication of vanes with a sharp trailing edge was considered to be one of the more challenging features for fabricating a ceramic composite vane. The vanes were densified through the chemical vapor infiltration/slurry cast/silicon melt-infiltration process. Both NDE inspection and metallographic examinations revealed that the final as-fabricated composite quality of the vanes was consistent with that typically obtained for the same composite material fabricated into flat panels. Two vane configurations were fabricated. One consisted of a thin wall (1.5 mm) shell with a continuously reinforced sharp trailing edge. The second vane configuration included a reinforcing web bridging the pressure and suction-side vane walls and the same reinforced sharp trailing edge. This paper will discuss the vane fabrication and characterization efforts.
Berichte der Organisationen zum Thema "Flax fibre production"
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Upadhyaya, Shrini K., Abraham Shaviv, Abraham Katzir, Itzhak Shmulevich und David S. Slaughter. Development of A Real-Time, In-Situ Nitrate Sensor. United States Department of Agriculture, März 2002. http://dx.doi.org/10.32747/2002.7586537.bard.
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Although nitrate fertilizers are critical for enhancing crop production, excess application of nitrate fertilizer can result in ground water contamination leading to the so called "nitrate problem". Health and environmental problems related to this "nitrate problem" have led to serious concerns in many parts of the world including the United States and Israel. These concerns have resulted in legislation limiting the amount of nitrate N in drinking water to 10mg/g. Development of a fast, reliable, nitrate sensor for in-situ application can be extremely useful in dynamic monitoring of environmentally sensitive locations and applying site-specific amounts of nitrate fertilizer in a precision farming system. The long range objective of this study is to develop a fast, reliable, real-time nitrate sensor. The specific objective of this one year feasibility study was to explore the possible use of nitrate sensor based on mid-IR spectroscopy developed at UCD along with the silver halide fiber ATR (i.e. attenuated total internal reflection) sensor developed at TAU to detect nitrate content in solution and soil paste in the presence of interfering compounds. Experiments conducted at Technion and UCD clearly demonstrate the feasibility of detecting nitrate content in solutions as well as soil pastes using mid-IR spectroscopy and an ATR technique. When interfering compounds such as carbonates, bicarbonates, organic matter etc. are present special data analysis technique such as singular value decomposition (SYD) or cross correlation was necessary to detect nitrate concentrations successfully. Experiments conducted in Israel show that silver halide ATR fiber based FEWS, particularly flat FEWS, resulted in low standard error and high coefficient of determination (i.e. R² values) indicating the potential of the flat Fiberoptic Evanescent Wave Spectroscopy (FEWS) for direct determinations of nitrate. Moreover, they found that it was possible to detect nitrate and other anion concentrations using anion exchange membranes and M1R spectroscopy. The combination of the ion-exchange membranes with fiberoptices offers one more option to direct determination of nitrate in environmental systems.