A indústria alimentícia tem oferecido ao consumidor muitas opções para aquisição de pães, dentre essas estão os pães enriquecidos e os integrais. A linhaça é um alimento com alegação funcional que vem se destacando pela presença do Omega-3, fibra solúvel e proteína, porém seu consumo é baixo devido à falta de hábito e também por escassez de informação dos consumidores. O objetivo do estudo foi formular pães com adição de grãos de linhaça nas concentrações de 3%, 6% e 9% e compará-los ao controle, sem adição de linhaça. Foram realizadas análises de determinação do perfil de ácidos graxos, composição centesimal, quantificação do teor de minerais, determinação de antinutricionais (ácido fítico, taninos, compostos fenólicos totais), digestibilidade de proteína in vitro, análise da qualidade dos pães através do peso da massa crua, peso da massa assada, perdas durante a cocção e índice de conversão. As propriedades físicas dos pães também foram avaliadas através da textura, volume e cor. As características sensoriais foram analisadas através de teste de aceitabilidade realizado em padaria com 116 provadores e também pela Análise Descritiva Quantitativa (ADQ) com 13 provadores treinados. Com os dados obtidos das análises químicas, elaborou-se um rótulo nutricional para cada formulação. Dentre os ácidos graxos quantificados, o palmítico, o oléico e o linoléico foram os maiores representantes nas 4 amostras de pães o que contribuiu para a frágil estabilidade dos produtos e para a formação de compostos indesejáveis, porém a presença de antioxidantes naturais nas sementes de linhaça controlou a oxidação lípidica. Nenhuma das amostras pode ser considerada fonte de fibra alimentar pelo fato de não conter 3g/100g de alimento pronto para consumo. O teor de fitatos presente nas amostras aumentou de acordo com a adição de sementes de linhaça. Nas 4 formulações de pães o teor de fitato diminuiu significativamente quando comparado ao da semente de linhaça. As amostras controle e com 6% de linhaça foram classificadas como volume específico Muito bom e as amostras com 3% e 9% de linhaça foram classificadas como volume específico Bom. Entre as amostras que receberam adição de linhaça, a amostra com 9% foi a melhor aceita pelos provadores e na ADQ, essa amostra apresentou médias superiores às demais em relação a maioria dos atributos levantados pelo provadores. Não foram identificados atributos indesejáveis para nenhuma das amostras através da ADQ. / Food industries offer to consumer several types of breads options which vary from whole wheat to enrich with multigrain such with flax seed. Flax seed is considered a functional food that has important content of omega 3 fat acids, soluble fiber and protein, however it intakes is very low in our diet. The aim of the research was to prepare a wheat bread enrich with flax seed at 3% or 6% or 9% concentration and to compare with a wheat bread control with no flax seed added. Analysis of fat acids composition, mineral composition, antinutritionals content (phytic acid, tannin, total phenolic compounds) and in vitro protein digestibility were carried out in the bread samples. Bread quality was evaluated analyzing the weight of the raw dough, the baked bread, and the lost during baking process and its conversion index. Physical properties of breads were evaluated for texture, volume and color. The sensory characteristics were evaluated using acceptability test with 116 panelists and by quantitative descriptive analysis (QDA) with 13 trained panelists. A nutritional label was formulated to each one of the bread preparations. The quantified fat acids profile showed that palmitic, oleic and linolenic acids were the most representative fat acids in the 4 bread sample analyzed. The presence of those fat acids possibly contributes to poor stability of product and for the development of undesirable compound. However, the presence of natural antioxidants in flax seed may help to control fat acid oxidation. None of the samples were considered source of dietary fiber because they have less then 3g/100 g of bread. The phytate content present in the samples increased according to the increase of flax seed concentration in the bread. Compared to raw flax seed, the phytate content in the bread samples were lower. The control and the sample with 6% of flax seed had the ranking for specific volume described as Very good and the samples with 3% and 9% of flax seed as Good. Between the bread samples, the best score in the acceptability test was obtained in the sample with 9% of flax seed. The same was observed for QDA which showed that the panel had high attributes for this sample compared to other ones. No undesirable attributes were identified in any other sample analyzed in QDA.

Les renforts à base de fibres de lin sont aujourd’hui une alternative capable de concurrencer les fibres synthétiques conventionnelles puisqu’ils sont écologiques, économiques et présentent des propriétés mécaniques intéressantes. Cependant, leur inconvénient majeur est leur absorption d’eau potentiellement importante qui affecte leurs propriétés mécaniques. Ce projet de recherche propose d’étudier le comportement hygroscopique et le couplage hygro-mécanique dans les composites lin / époxy. Cette étude repose sur une approche expérimentale multi-échelle et une modélisation du comportement visco-élasto-plastique avec prise en compte du couplage hygro-mécanique des composites renforcés par des fibres de lin. Les cinétiques de diffusion dans l’époxy et dans le composite ont été modélisées par une loi de type Langmuir et Fick respectivement. Les coefficients d’hygro-expansion des composites et des fils élémentaires qui constituent le renfort tissu ont été déterminés expérimentalement. Une étude de l’influence du conditionnement jusqu’à saturation à différentes humidités relatives sur le comportement mécanique dans les trois directions du stratifié a également été menée. Cette étude a montré l’existence d’une teneur en eau optimale pour laquelle les propriétés mécaniques sont optimales. L’émergence d’un comportement à deux régions linéaires a été mise en évidence et attribuée à la présence d’hétérogénéités locales au sein du renfort tissu. Des essais de fluage / recouvrance et de relaxation / effacement ont permis de mettre en place un modèle visco-élasto-plastique avec prise en compte du couplage hygro-mécanique. Ce modèle offre de bonnes capacités de prédiction et permettra de prévoir le comportement des structures composites renforcés par des fibres de lin en atmosphère humide. / Flax fibre reinforcements are nowadays an alternative able to compete with conventional synthetic fibres since they are ecological, economic and have interesting mechanical properties. However, their major drawback is their potentially significant water absorption which affects their mechanical properties. This research project proposes to study the hygroscopic behaviour and hygro-mechanical coupling in flax / epoxy composites. This study is based on a multi-scale experimental approach. A modelling of visco-elasto-plastic behaviour taking into account the hygro-mechanical coupling within flax /epoxy composites is established. The diffusion kinetics in composites were modelled by a Fick law. However, the diffusion kinetics in epoxy were modelled by a Langmuir law. The hygro-expansion coefficients of the composites and the elementary yarns that constitute the fabric reinforcement were determined experimentally. A study of the influence of conditioning until saturation at different relative humidities on the mechanical behaviour in the three main directions of the laminates was conducted. This study showed the existence of an optimal water content for which the mechanical properties are maximum. The emergence of a two-linear-region behaviour was pointed out and attributed to the presence of local heterogeneities within the fabric reinforcement. Creep / recovery and stress relaxation tests were exploited in order to develop a visco-elastoplastic model with consideration of the hygro-mechanical coupling. This model offers good predictive capabilities and could be used to predict the behaviour of flax fibres reinforced composite structures in humid atmospheres.

The sagebrush steppe is a particularly sensitive ecosystem that is easily disturbed by fires, oil and gas extraction, woody-plant encroachment, and overgrazing. The natural regeneration of native species following a disturbance within this system is typically slow and sporadic, which allows invasive grasses to occupy the landscape. Attempts to assist the recovery of these landscapes through direct seeding is commonly met with poor success rates, particularly in lower elevation, drier sites. Novel seed enhancement technologies and planting techniques that mitigate limiting factors impairing restoration efforts may improve the likelihood of restoring these degraded areas. For chapter 1, we evaluated a solid-matrix priming technique, where bluebunch wheatgrass (Pseudoroegneria spicata) and Lewis flax (Linum lewisii) were primed and then the priming matrix and seed were pelleted together. We evaluated primed seed that had been incorporated into pellets at two field sites against seed that was pelleted but been left unprimed, and untreated seed (control). These three seed treatments were planted in the spring (mid-march) in shallow (2-cm) and deep (15-cm) furrows, in a complete factorial design. We found that primed seeds generally produced higher plant densities than control seed at the beginning of the growing season; however, its influence diminished towards the end of the growing season. We also found that deep furrows increased plant density throughout the growing season and even into the following year. The combination of priming and deep furrows outperformed control seed in shallow furrows in all measured metrics. For chapter 2, we evaluated a seed conglomeration technique for improving Wyoming big sagebrush (Artemisia tridentata ssp. Wyomingensis) emergence and survival under fall and winter plantings. The trial was implemented at five sites across Utah and Nevada in a randomized complete block-split-split plot design, with site, and planting season, comprising the split-plot factors. Each site and season combination was seeded with conglomerated and control seed. We found that in most cases, a fall seeding of Wyoming big sagebrush was either the same or more successful compared to planting on the snow in the winter, which is the current suggested practice. Our results also demonstrated that seed conglomeration produced higher plant densities compared to control seed throughout the growing season. The higher density of plants produced from conglomerates combined with the improved seed delivery provided by the conglomeration technique was estimated to offset the cost in producing conglomerates and reduce overall restoration costs by 41%.

Hybrid composites play a key role in sustainable development. For many years, carbon fibres in an epoxy matrix have been an attractive option for many structural applications because of their higher specific mechanical properties mostly. However, recycling and sustainability are some of the composite shortcomings; and in that context, natural fibres have gained popularity.  The present study aimed to design and manufacture short carbon/flax hybrid composites. Two different arrangements were chosen: random and layers configuration. Resin Transfer Moulding (RTM) was used to fabricate these hybrid composites. Mechanical tests and optical microscopy technique were conducted to understand the effect of the interaction of these two different reinforcements. Mechanical tests showed a remarkable difference between the hybrid configurations under flexural loadings. Furthermore, outstanding property values were observed in the hybrid configurations compared to single fibre composites. The resultant materials have seemed an attractive combination of fibres with a remarkable balance between mechanical performance and eco-friendliness.

Increasing demand for new progressive construction materials requires development of modern environmentally friendly materials with excellent end-use properties and reasonable price. One of the main objectives of material research in building industry is using renewable resources of raw materials of industrial waste for development of new construction materials. Current trend of thermal insulation of building constructions results in development of environmentally friendly insulation materials based on renewable material resources from agriculture and stock farming, which could became alternative for current common use insulation materials in the future. The thesis describes research and development of insulation materials based on natural fibres of agricultural origin; in particular fibres of hemp, flax and jute. Hydrothermal behavior of developed materials is studied including computational simulation of behavior of researched materials after building in the construction.

No description available.

This thesis investigates sound transmission loss through flat finite panels using composite materials, which incorporate both carbon and flax fibres. The study wascarried out by performing FEM simulations developed and validated in steps. Thevalidation process was time-consuming but crucial in ensuring the model’s reliability.The analysis demonstrates the relationship between the panels’ mass, stiffness, andsound reduction effectiveness by studying the sound transmission loss for a flat plate.The results show how by adjusting the plate’s stiffness, thickness, and mass one cancontrol its reaction to the incoming sound. This allows resonance frequencies to beshifted away from critical points and avoids coincidence frequencies. By understanding the acoustic behavior of composite panels, this research contributes to improvingsoundproofing properties while preserving their mechanical advantages. In an era ofgrowing demand for better acoustic performance in the automotive industry, exploring innovative methods to optimize the sound transmission loss of composite panelsis essential. / Denna studie undersöker ljudöverföringsförluster genom platta finita paneler sombestår av kompositmaterial, som innehåller både kol- och linfiber. Studien utförFEM-simuleringar som utvecklats och validerats i steg. Valideringsprocessen vartidskrävande men avgörande för att säkerställa modellernas tillförlitlighet. Analysenvisar sambandet mellan panelernas massa, styvhet och ljudreducerande effektivitetgenom att studera ljudtransmissionsförluster för en platt panel. Resultatet visarhur justering av plattans styvhet, tjocklek och massa kan styra dess reaktion på detinkommande ljudet, vilket gör att resonansfrekvenser kan flyttas bort från kritiskapunkter och undvika sammanfallande frekvenser. Genom att förstå det akustiskabeteendet hos kompositpaneler bidrar denna studie till att förbättra ljudisoleringsegenskaperna samtidigt som deras mekaniska fördelar bevaras. I en tid av växande efterfrågan på bättre akustisk prestanda inom bilindustrin, blir det viktigt att utforska innovativa metoder för att optimera ljudöverföringsförlusten hos kompositpaneler.

L'objectif du projet de thèse est d'étudier et d'analyser le comportement mécanique à l'impact et en post impact de composites à fibres végétales. Le déroulement de cette thèse nécessite : L'élaboration et la caractérisation des matériaux de l'étude : Les matériaux de l'étude seront constitués de tissus à fibres végétales (lin et/ou chanvre) imprégnées de résine thermodurcissable (de type époxyde) ou thermoplastique (de type PP ou PLA). Ceux-ci seront fabriqués sous forme de plaque par la technique d'infusion sous vide ou la technique de la thermocompression, en fonction du type de résine. La caractérisation mécanique sera effectuée à partir d'essais mécaniques statiques et d'essais d'impact avec une tour de chute (à plusieurs niveaux d'énergie). Celle-ci sera d'abord menée sur des éprouvettes modèles (non impactées et non vieillis, sans et avec renfort fibreux) puis sur des éprouvettes dégradées (impactées à chaque niveau d'énergie et vieillis en humidité et température). La caractérisation de l'endommagement : Elle permettra, à partir des analyses d'images associées aux techniques de l'émission acoustique, de localiser et d'identifier les différents mécanismes d'endommagement intervenant dans ces matériaux au cours des diverses sollicitations choisies. Cette étude conduira à définir le degré de nocivité de ces endommagements tout en associant à la démarche l'influence des paramètres microstructuraux tels que la nature du renfort fibreux et des constituants (résine et fibres). L'identification de modèles de comportement : Il s'agit de proposer une méthode d'identification des paramètres matériaux de modèles de comportement tenant compte de l'endommagement au niveau de la microstructure du matériau (résine et torons de fibres). Cette étude conduira à la mise en œuvre d'une méthode de type recalage de modèles éléments finis en utilisant les bases de données expérimentales constituées notamment des mesures de champs cinématiques. L'objectif à terme est de disposer de modèles fiables et prédictifs pour le calcul de structures de ces matériaux dans l'industrie / The purpose of this PhD project is to study and analyze the mechanical behavior during the impact and post-impact of plant-fiber based composite materials. The conduct of this thesis requires: The manufacturing and characterization of the materials involved in the study : The materials are composed of plant-fiber fabrics (flax and/or hemp) impregnated with thermosetting resin (epoxy type) or thermoplastic resin (PP or PLA). These are manufactured using the vacuum infusion process or using thermocompression, depending on the resin. The materials are plate-shaped. The mechanical characterization will be performed using static mechanical testing and impact testing with a drop tower (over several energy levels). This will be first conducted on unmodified specimens (unimpacted and unaged, with and without fiber reinforcement) then on degraded specimens (impacted with a known energy and/or aged in humidity and temperature). The characterization of damage: It will, from the analysis of the images associated to the techniques of the acoustic emission, locate and identify the various damage mechanisms that intervene in these materials during different stresses. This study will lead to define the degree of harmfulness of such damage while associating to the approach the influence of microstructural parameters such as the nature of the fiber reinforcement and the components (resin and fibers). The identification of behavioral patterns: It consists in suggesting a method to identify the material parameters of behavioral patterns while taking into account the damage level of the material's microstructure (resin and fiber strands). This study will lead to the implementation of a finite element model updating-like method using experimental databases such as kinematic field measurements. The ultimate purpose is to have reliable and predictive models in order to calculate the structures of such materials in the industry

There is growing public concern about the high proportion of saturated fatty acids in milk fat; however, feed intake, energy partitioning toward milk synthesis, and milk fat concentrations can decrease when cows are fed high concentrations of unsaturated lipids. The objective of this study was to identify the optimal rate for feeding OmegaBoostTM (a flaxseed supplement that was processed using a proprietary technique by Double Pass LLC, Tualatin, OR) to dairy cows. The central hypothesis was that supplementation with OmegaBoost will decrease the proportion of saturated fatty acids in milk fat in a dose dependent manner. Using a latin-square design, 10 Holstein cows in mid to late lactation were fed for two-week periods 0, 2, 4, or 6 lbs/d of OmegaBoost or 4lbs/d ground flax as top dressing to their total mixed ration. Feed intake, body weight, activity and resting time, milk production and milk composition were measured daily. At the end of each two-week period, milk and serum samples were taken and analyzed for fatty acid composition using gas chromatography. In addition, fresh Mozzarella cheese and butter was manufactured and tested to determine the fatty acid composition and the effects of flaxseed supplementation on texture. Feeding OmegaBoost at 2, 4, and 6 lbs/d linearly decreased the proportion of saturated fatty acids in milk by 6, 15, and 18%, respectively, and linearly increased the proportion of mono-unsaturated fatty acids (14, 32, and 35%), poly-unsaturated fatty acids (16, 49, and 82%), and α-linolenic acid (26, 52, and 70%). Similar changes in fatty acid composition were observed in butter and cheese samples, resulting in butter that was less hard and adhesive at refrigeration temperature in response to feeding cows increasing concentrations of OmegaBoost. Feed intake, body weight, serum metabolite concentrations, milk production and composition, and butter and cheese yield were not significantly affected by feeding processed flaxseed. Therefore, feeding 4 or 6 lbs/d of OmegaBoost to dairy cows is effective in improving the nutritional and textural profile of dairy products without negatively affecting feed intake, milk production, or weight gain. / Graduation date: 2012

Le travail développé dans cette thèse a pour but d’étudier le comportement hygrothermique de matériaux isolants bio-sourcés, et plus particulièrement les fibres de bois, le béton de chanvre, la laine de lin, la laine de mouton, le métisse® et les anas de lin. Ces matériaux, par essence naturels, présentent des spécificités liées à leur origine (animale ou végétale) et à leur structure (fibres, paille, matrice solide…). Leur porosité, très élevée, les rend réactifs aux variations d’humidité relative ambiante, ce qui peut impacter leurs performances thermiques et leur durabilité (comme pour tous les matériaux), mais également leur conférer des capacités de régulation. Dans un souci d’améliorer la connaissance de ces matériaux particuliers, nous proposons tout d’abord d’étudier l’impact causé par l’humidité sur leurs caractéristiques thermiques, principalement la conductivité thermique et la chaleur spécifique. Ensuite les caractéristiques hygrothermiques sont étudiées, ce qui permet de mieux comprendre les phénomènes dépendant des capacités d’adsorption, de désorption, de perméabilité ou de résistance à la vapeur d’eau. On se rend compte également de l’importance du gradient de température sur l’évolution des transferts hygriques au sein des matériaux. En plaçant les isolants bio-sourcés sous sollicitations aléatoires ou en conditions réelles d’utilisation, nous pouvons suivre leur comportement d’un point de vue expérimental. Le couplage à une approche numérique permet d’identifier les paramètres d’influence prépondérants, dans l’optique de la prédiction des transferts couplés chaleur/masse par une simulation dans des conditions particulières d’utilisation, comme la rénovation d’un habitat existant. On constate à partir de mesures in situ que ces matériaux ont une grande capacité d’adaptation à des environnements dont l’humidité relative est évolutive. / The work developed in this thesis aims to study the hygrothermal behavior of bio-sourced insulating materials, and more particularly wood fibers, hemp concrete, linen wool, sheep wool, material made of textile recycling (metisse®) and flax shives. These materials, which are essentially natural, have specific characteristics linked to their origin (animal or vegetable) and their structure (fibers, straw, solid matrix, etc.). Their very high porosity makes them reactive to the relative humidity variations, which can affect their thermal performances and their durability (as for all materials), but also give them a regulation capacities. In order to improve the knowledge of these particular materials, first, we propose to study the impact caused by moisture on their thermal characteristics, mainly thermal conductivity and specific heat. Then the hygrothermal characteristics are studied, which makes it possible to better understand the phenomena depending on the capacities of adsorption, desorption, permeability or water vapor resistance. Also, we realize the importance of the temperature gradient impact on the evolution of the hygroscopic transfers within the materials. By placing the studied bio-sourced insulation materials under random loading or under real conditions, it will be possible to follow their hygrothermal behavior from an experimental point of view. The numerical approach makes it possible to identify the preponderant influence parameters, in the context of the prediction of coupled heat and mass transfers by simulation under particular conditions of use, such as the renovation of an existing habitat. On the basis of in situ measurements, it can be seen that these materials have a high adaptability to environments whose relative humidity is evolutionary.