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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Experimental Investigation of Shear Thickening Fluid Impregnated Flax Fabric and Flax/Kevlar Hybrid Fabrics

Fehrenbach, Joseph Brian January 2020 (has links)
Shear thickening fluids have the potential to improve the effectiveness of fabric materials in body armor applications as they have shown to increase the puncture and ballistic resistance of Kevlar fabrics. However, the effect of using STFs with natural fabrics such as flax has never been studied. The rheology of STFs at varying concentrations of nanosilica dispersed in polyethylene glycol PEG was studied at different temperatures and it was found that the STFs behave as a non-Newtonian fluid in response to changes in shear rate. In this study the effectiveness on the puncture and ballistic resistance of impregnating flax fabric with STF of nanosilica in PEG were investigated. The effect of hybridization of flax and Kevlar was also investigated. The puncture and ballistic resistance of the samples treated with STFs was found to increase significantly and can be controlled by STF concentration.
92

Formulation and Sensory Evaluation of Gluten-Free Muffins Containing Flax

Woodyard, Adam Michael 06 August 2011 (has links)
Celiac disease is characterized by an allergic reaction to gluten that causes inflammation of the small intestine and can lead to malabsorption and malnutrition. Glutenree products are being developed that meet dietary needs of individuals with celiac disease. However, these products often lack whole grains and fiber. Fortification of glutenree products with flax can increase nutritional value and alleviate inflammation. Sensory analysis (N=152) was conducted to evaluate the acceptability of glutenree muffins with moderate (3.8%) and high (7.4%) amounts of added flax. Results indicated that consumers preferred (p<0.05) the muffin without flax or the highlax muffin more than the muffin with the moderatelax treatment. The highlax and control treatments were rated 6.7, between like slightly and moderately like; the muffins from the moderatelax treatment were rated 6.4 on a nine-point hedonic scale. Producers of glutenree products could potentially formulate muffins that include flax and are acceptable to consumers.
93

Critical Evaluation of Techniques for the Identification of Archaeological Bast Fibres: Flax, Hemp and Nettle

Waudby, Denis B. January 2019 (has links)
Fibre plants favour different growth conditions and require different levels of husbandry. However, the fibres share some physical and material properties, which make them difficult to distinguish in the archaeological record. This thesis evaluates the effectiveness of methods for characterising bast fibres including; fibre chemical analysis, mechanical testing and fibre morphology, to propose that longitudinal microfibrillar angle (MFA) and cross-sectional circularity (Ct) used in a two-step procedure to analyse selected modern fibres of nettle (Urtica dioica L.), flax (Linum usitatissimum L.) and hemp (Cannabis sativa L.) could offer an alternative approach. The reliability of MFA and Ct, as diagnostic features, was evaluated under a temperature accelerated degradation 48week trial with eight fibre types from three deposition soils Post deposition, surviving fibres were subjected to evaluation of changes in MFA and Ct. An additional check on the diagnostic efficacy was conducted within a blind-test protocol. Finally, the research programme employs MFA and Ct in the diagnosis of a range of archaeological textile fibres from museum collections and fibres from the Kasr el Yahud mass burial. The thesis includes recommendations to address future post thesis research programmes.
94

Characterization of DNA polymorphisms associated with environmentally induced heritable changes in flax

Schneeberger, Richard Gerald January 1992 (has links)
No description available.
95

The Effect of Antioxidants on Flaxseed Stability in Yeast Bread

Cachaper, Katherine Faith 07 April 2005 (has links)
The antioxidants BHA, BHT, and ascorbic acid were added to flaxmeal breads to prevent rancidity. Six types of yeast leavened breads were evaluated: control (100% bread flour), flaxmeal (15%) bread, and flaxmeal (15%) bread that contained 0.01% respectively of BHA, BHT, BHA and BHT, and ascorbic acid. Vital wheat gluten was added in all the flaxmeal breads. Chemical, objective and sensory tests were used to evaluate the breads. The crumb texture of all the experimental breads was significantly softer (p¡à 0.05) than the control breads, but the control breads were significantly moister (p¡à 0.05) than the flaxmeal breads that contained BHA and BHT, separately. No significant differences (p>0.05) were found in loaf volume of the control bread and the experimental breads. The crumb color of the experimental breads was significantly darker (p<0.0001) due to the incorporation of flaxmeal. The acid value of the flaxmeal breads was significantly higher (p¡à 0.05) than the control breads. No significant differences (p>0.05) were found in peroxide values between the control breads and experimental breads after eight weeks. The QDA sensory tests showed that breads containing BHA or in combination with BHT were moister, chewier and had the least noticeable stale taste when compared to the control breads. Ascorbic acid was not as effective as BHA or a combination of BHA and BHT in preventing lipid oxidation, but produced the softest bread. This study showed that flaxmeal breads made with BHA and BHT provided the best protection against lipid oxidation and produced a moist and chewy bread. / Master of Science
96

Développement et caractérisation d'un matériau composite à base de fibres de lin : application au renforcement de structures en béton par collage externe / Development and characterization of a flax fibers reinforced composite : application to reinforcing concrete structures by external sizing

Hallonet, Anne 08 July 2016 (has links)
Afin de prolonger leur durée de vie et d'assurer la sécurité des usagers, les structures en béton peuvent nécessiter un renforcement au cours de leur durée de service. La technique de renforcement par collage externe, en surface, de composites renforcés de fibres de carbone, de verre ou d'aramide à l'aide de résines durcissant à température ambiante est largement employée pour son efficacité et sa facilité de mise oeuvre. Toutefois l'utilisation à la fois de fibres synthétiques et de matrices polymères produit un impact écologique non négligeable. L'objectif de ce travail de recherche est d'examiner la possibilité d'utiliser des fibres de lin pour le renforcement externe de structures en béton. Les propriétés mécaniques spécifiques et le bilan environnemental avantageux des fibres de lin en font une alternative intéressante aux fibres de verre. Cependant leur origine naturelle conduit à une plus grande variabilité des propriétés, à un comportement en traction non linéaire et une sensibilité accrue à l'humidité. Les principaux objectifs du travail de thèse portent ainsi sur la sélection des matériaux et la mise en oeuvre les plus adaptés, sur l'évaluation des performances du matériau et de son adhérence au support béton et sur une évaluation de la durabilité des propriétés du système. Dans une première partie expérimentale deux méthodes de mise en oeuvre du renfort à fibres de lin (stratification au contact et collage de lamelles rigides) sont développées et caractérisées. Des observations tomographies X confirment la bonne imprégnation des fibres et la cohésion des composites. Les essais de traction révèlent un comportement en traction bilinéaire comme décrit dans la littérature, avec des propriétés d'effort par largeur de bande comparables aux composites de renfort à fibres de verre. La caractérisation des interfaces composite/béton menée par tests de cisaillement à double recouvrement confirme une bonne adhérence qui se traduit par une rupture cohésive dans le substrat béton. La nature des fibres ne semble pas influencer le comportement de l'interface. Les systèmes de renforcement à fibres de lin sont donc capables de reprendre des efforts transmis par cisaillement de façon comparable aux matériaux de renfort à fibres de verre. Dans une deuxième partie des essais exploratoires de durabilité ont ensuite été menés pour vérifier la pérennité des propriétés de ces deux composites de renfort dans un environnement de service. Un vieillissement accéléré artificiel en enceinte climatique est mis en place tandis que des composites à fibres de lin stratifié au contact sont exposés pendant un an à l'environnement extérieur. Un second vieillissement hygrothermique à 70°C est mené pendant 4 semaines. Les dégradations des propriétés des composites à fibres de lin sont comparables à celles de certains composites de renfort à fibres de verre. Malgré la nature hydrophile des fibres de lin, les premiers essais ne montrent pas de dégradations des propriétés qui rendraient le composite impropre à une utilisation comme renfort extérieur de structures en béton / To extend their life and ensure the safety of users, concrete structures may need strengthening during their service life. The technique of strengthening by external bonding of composites carbon, glass or aramid composites using polymer that are cured at room temperature is widely used for its effectiveness and ease of implementation. Yet the uses of both synthetic fibers and polymer matrices have a significant environmental impact. The objective of this research is to examine the possibility of using flax fibers for the external strengthening of concrete structures. Their high specific mechanical properties and positive environmental balance make them an interesting alternative to the glass fibers. However, they also present a larger variability in properties, a non-linear tensile behavior and high sensitivity to humidity. The main objectives of this thesis involve the selection of the materials and the most suitable implementation, the evaluation of the materials’ performances and adherence to concrete support and a sustainability assessment of those properties. In a first experimental section, two methods of implementation of the flax fiber reinforcement are developed and characterized: by wet lay-up and by bonding of pre-hardened. Tomography observations confirm the good fiber impregnation and cohesion of the composites. The tensile tests show a bilinear tensile behavior as described in the literature, with stress per width at failure comparable to glass fibres strengthening systems. The characterization of composite/concrete interfaces is conducted by double overlap shear tests and confirms a good adhesion which results in concrete failure before the failure of the reinforcement system. The nature of the fibers does not appear to influence the shear behavior of the interface. For glass or flax wet lay-up systems, failure can occur with failure of the composite. Flax fiber reinforcement systems can take up the forces transmitted by shear in a manner comparable to glass composites. In the second part, sustainability tests were conducted to ensure the sustainability of the properties of these two composite reinforcements in a service environment. An artificial accelerated aging test in a climatic chamber is set up while wet lay-up flax fiber composites are exposed to the external environment during a year. A second hydrothermal aging test is conducted for 4 weeks at 70°C. The degradations of the properties of the flax composites are comparable to those of some glass reinforcement composites. Despite the hydrophilic nature of the flax fibers the first tests show no degradation of properties that would make the composite unsuitable for an external reinforcement of concrete structures
97

INCORPORATION OF BIO BASED FLAX FIBER REINFORCED POLYMER SKINS FOR PACKAGING ENHANCEMENTS

Sufia Suleman Sukhyani (11679325) 20 December 2021 (has links)
This thesis provides an approach to incorporate natural composites like Flax Fiber using a resin with 30% bio-content to enhance the packaging boxes made of corrugated cardboard. The objective of introducing natural composite skins is to reduce/eliminate the compressive loading subjected to the boxes while stacking in warehouses.
98

Incorporation of Bio Based Flax Fiber Reinforced Polymer Skins for Packaging Enhancements

Sukhyani, Sufia 12 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / This thesis provides an approach to incorporate natural composites like Flax Fiber using a resin with 30% bio-content to enhance the packaging boxes made of corrugated cardboard. The objective of introducing natural composite skins is to reduce/eliminate the compressive loading subjected to the boxes while stacking in warehouses.
99

Genetic and physiological aspects of flax morphogenesis induction / Linų morfogenezės indukcijos genetiniai ir fiziologiniai aspektai

Masienė, Ramunė 23 January 2014 (has links)
Research objective. Investigation of consistent patterns of the induction of flax morphogenesis process, assessment of genetic and physiological aspects of this process and optimization methodologies. Proposition: 1. MOrphogenesis capacity of flax isolated explants depends on a genotype only, but on a composition of a medium and the cultivar type (fibre flax or linseed)also. 2. Cells of different organs of the same genotype have different morphogenic capacity. 3. Combining hormonal ratio with the affect on explats by exogenic factors enables targeted control of the morphogenesis process in vitro. / Darbo tikslas - ištirti linų morfogenezės proceso indukcijos dėsningumus, įvertinti šio proceso genetinius ir fiziologinius aspektus bei optimizuoti regeneravimo metodikas. Ginamieji disertacijos teiginiai: 1. Linų izoliuotų eksplantų morfogeninė galia priklauso ne tik nuo genotipo, maitinamosios terpės sudėties, bet ir nuo veislės tipo (pluoštiniai ar sėmeniniai). 2.To paties genotipo skirtingų organų ląstelės turi skirtingą morfogeninę galią. 3.Derinant hormoninį balansą su eksplantų paveikimu egzogeniniais veiksniais galima kryptingai valdyti morfogenezės procesą in vitro.
100

Genetic analysis of seed and flower colour in flax (Linum usitatissimum L.) and identification of a candidate gene in the D locus

2013 August 1900 (has links)
Flax (Linum usitatissimum L.) is a commercial oilseed crop in Canada. Globally flax is known for industrial oil and fiber. Flaxseed contains Omega 3 fatty acid, lignans like secoisolariciresinol diglucoside (SDG), flavonoids and polysaccharides which offer potential health benefits. Conventional flax cultivars are brown seeded and few mutant lines are yellow seeded. The darkness of seed colour depends on the presence of polymerized proanthocyanidins (PA; condensed tannins) in the seed coat. PAs are the product of the phenylpropanoid pathway. Previous genetic studies by Mittapalli and Rowland (2003) on G1186/94 showed the seed colour trait was governed by the homozygous recessive alleles at D locus and the same locus is closely linked to white or pink flower petals. To start with, single seeds of already developed stable recombinant inbred lines (RILs) (of F8:9 generation) from a cross of yellow seeded European recessive line (G1186/94) and brown seeded CDC Bethune (popular variety) were grown. In this study, seed colour phenotyping was done by measuring seed colour of each RIL in Red-Green-Blue (RGB) values. To understand the genetic basis of flax seed and flower colour, mapping with single sequence repeats (SSRs) and CAPS (Cleaved Amplified Polymorphic Sequences) markers were used. For the first time, a framework genetic linkage map was constructed from populations of CDC Bethune/ G1186/94 containing 19 linkage groups (LGs). LG 1 with four SSR markers was found to be linked with the seed colour locus D. During the fine-mapping, two SSR markers (LuM566 and Lu2351) were found to be linked with the seed colour trait. The D locus has been confined in a 2.8 cM region and the closest marker was LuM566 at a distance of 0.6 cM. This was observed to be a stable locus in two growth trials and in different environments with logarithm of odds (LOD) above 39 and more than 84 % of the trait expressed by the major locus in both trials. As there were no recombinants (off types) for flower colour in F8:9 plants i.e brown-seeded lines produced blue flowers and yellow-seeded lines produced white flowers, the same locus holds well for the flower colour trait. The marker associated with seed and flower colour in G1186/94 (European recessive yellow line) was identified and can be used in flax breeding. Additionally, an interesting putative candidate gene of potential significance was identified through genomics assisted gene search from the flax whole genome sequence database. The gene expression analyses showed lower expression of putative flavonoid 3’ hydroxylase (F3’H) (a gene involved in flavonoid biosynthesis pathway) in both seed coat and flower petal tissues of G1186/94 as compared to CDC Bethune. Therefore, this study represents the first report on genetic mapping based putative candidate gene finding for recessive yellow seed colour mutation in the D locus in flax.

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