Tesis sobre el tema "Pièces de bois en chêne"
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Dahbi, Radouan. "Conception d’une chaîne de traitements pour la segmentation texture d’images multimodales de pièces de bois en chêne. Application à la détection des singularités et la discrimination du grain du bois". Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0143.
Texto completoThe work presented in this CIFRE thesis, associating CRAN and CRITT Bois for the ANR-OPTIFIN project, contributes to the development of an image processing chain for the texture segmentation of multimodal images of sawn oak timber pieces. The idea is to combine multimodal acquisition techniques in visible and near-infrared (NIR) range with texture analysis methods using covariance matrices and texture segmentation methods in the Riemannian manifold, for the detection of singularities and discrimination of wood grain. In the first chapter, we present a state of the art on automated inspection of wood pieces; with a special focus on hardwood species (e.g. oak) for which inspection is still an open problem. The second chapter deals with the implementation of the multimodal imagery platform (PIM) and the calibration of color, grayscale, direct and scatter images in the visible range and abundance maps, obtained from NIR hyperspectral images. We propose an original methodology for the scatter images by optimizing the acquisition parameters on sawn oak timber pieces. The third chapter concerns the study of the registration of monomodal and multimodal images and the application of a method for the suppression of their background. In the fourth chapter, we propose a texture analysis methodology based on the fusion of multimodal images and/or their textural images (LBP, nriLBP, GLCM and Gradient) by covariance matrices. We exploit the covariance matrices by K-means clustering andk-ppv supervised classification methods, extended to the Riemannian case, for segmentation. In the last chapter, we present results ensuring a relevant and fast segmentation of the covariance matrices. They are obtained after having determined the best parameters for the K-means setting. The clustering results show that the use of multimodal images alone leads to an optimal segmentation of compact singularities. They also show the importance of integrating textural images in the modality sets to obtain a better segmentation of regional type singularities. For wood grain, an efficient segmentation is obtained by using only textural images. Finally, we propose to apply k-ppv in the Riemannian manifold on the selected modalities to obtain a more accurate segmentation
Deguilloux, Marie-France. "Traçabilité des bois de chêne : méthodes moléculaires et applications". Nancy 1, 2002. http://www.theses.fr/2002NAN10229.
Texto completoIn response to phytosanitary, commercial, legal or ecocertification concerns, numerous actors of the forestry industry are looking for a reliable technique permitting to control wood origin. Ln this study, molecular markers adapted to the analysis of oak wood were developed. The important database on chloroplast DNA variability of European white oaks has allowed to precisely map this variation, which is characterised by a strong geographical structure throughout the European continent. This work is divided in three steps. (i) First, the potential of dry wood for genetic analyses was defined. The DNA isolated from wood is largely degraded and present in low amounts. Genotyping sucess rates increase on fresh sapwood and if targeted sequences are short and present in high copy number per ceIl. (2) Second, molecular methods were developed to characterise wood haplotypes. Five different PCR-RFLP combinations can be used for that purpose. They allow to check statistically the conformity of the haplotypes detected on wood samples with those encountered in the hypothetical region of origin. A new search for polymorphism bas been conducted in order to better distinguish French or European regions. Some new PCR-RFLP combinations allowed to detect additional variation in Franœ, whereas chloroplast microsatellites were designed that could permit the automation of genotyping procedures. Finally, the collection of chloroplast microsatellites variability data allowed us to initiate a study of their evolution. A clear relation between level of variation and microsatellite length has been demonstrated, which should be taken into account in interspecific comparisons. (3) The last study conccrned two different applications of these molecular methods for wood genotyping. The first is an industrial application: the method was adapted to the control the geographical origin of oak wood used to make barrels. The second is in the field of paleogenetics and archaeology: the typing of ancient oak wood allowed to better understand the action of Man on oak populations and the past use of this resource
Nonier, Marie-Françoise. "Recherches sur les macromolécules du bois de chêne de tonnellerieInteractions avec les flavan-3-ols des vins et les aldéhydes du bois de chêne". Bordeaux 1, 2007. http://www.theses.fr/2007BOR13400.
Texto completoDemanet, Amélie. "Interactions mécaniques eau/bois et application à l'étude du collapse du chêne". Bordeaux 1, 1998. http://www.theses.fr/1998BOR10552.
Texto completoSlaghenaufi, Davide. "Contribution à la caractérisation des précurseurs d’arôme glycosylés du bois de chêne". Thesis, Bordeaux 2, 2012. http://www.theses.fr/2012BOR21987/document.
Texto completoThe presence of lactic acid bacteria (LAB) in oak barrels induces an increase in wood volatile compounds concentration. This phenomenon could be due to the glycosidic activity of LAB. The glucosidic precursor of a major woody aroma compound (oak lactone) was identified and quantified in oak wood but no data was available concerning the presence of other flavor precursors in oak wood. This study showed that monoglycosidic precursors did not exist in oak, in spirits and in wines. The study was performed by UPLC-FT/MS, using vanillin-β-D-glucopyranoside, vanillin-β-D-xylopyranoside, and coniferaldehyde-β-D-glucopyranoside as standards. These molecules were synthesized by phase transfer reaction. Purification of a vanillin glycoside precursor was done by centrifugal partition chromatography (CPC). The choice of the solvent system was based on an equal distribution in both phases of the aromas released by enzymatic hydrolysis. This led to the determination of the new concept, the activity partition coefficient Kca. After purification and fractionation, vanillin galloylglucoside, trimethoxyphenol-galloylglucoside and macarangioside E were isolated from wood and identified by HPLC-ESI-MS and NMR analysis. These precursors were quantified in different oak species by HPLC-QqQ-MS. These three compounds are precursors of vanillin, 3,4,5-trimethoxyphenol and 3-oxo-α-ionol respectively. The macarangioside E can lead by thermal degradation, to megastigmatrienone and 4-oxo-isophorone which have aromatic notes of tobacco and incense. These compounds are involved in the woody aroma of the wine and the genesis of the bouquet
Masson, Eric. "Incidence du mode de séchage sur les caractéristiques physico-chimiques du bois de chêne de tonnellerie (Quercus petraea (Matt. ) Liebl. )". Nancy 1, 1999. http://www.theses.fr/1999NAN10302.
Texto completoAssouad, Ahmad. "Modélisation du séchage sous vide discontinu du bois de chêne : intégration d'un critère de qualité mécanique". Bordeaux 1, 2004. http://www.theses.fr/2004BOR12844.
Texto completoThe aim of this work is the improvement of the dried oak wood quality through the definition of the optimal conditions for drying as well from the mechanical point of view as from the point of view of drying duration. The work is based on the development of a model describing heat and mass transfer during the discontinuous vacuum drying coupled with a model describing the stress field. A sensitivity study makes possible to define the optimal parameters for the process control. The optimal conditions obtained are validated through the drying experiments
Barrera, Garcia Veronica Daniela. "Sorption de composés phénoliques du vin par le bois de chêne : approches macroscopique et moléculaires". Dijon, 2007. http://www.theses.fr/2007DIJOS071.
Texto completoDuring ageing in oak barrels, wine acquires aromatic complexity as a result of mass transfer at the interface between wood and wine. During the past several years, a variety of studies has related the contribution of wood aroma compounds to wine. Researches concerning the sorption of wine molecules by oak wood have been initiated. However, the mechanisms dictating in the sorption process have not yet been determined. In this work, the transfer of wine phenolic compounds into oak wood under conditions simulating wine ageing were studied used both macroscopic and molecular approaches. Kinetic studies were carried out with the aim of calculating the apparent diffusion coefficients of phenolic compounds in a ternary system containing phenolic compounds, wine, and wood. The thermodynamic study, specifically with the construction of sorption isotherms, showed that the mechanisms and the sorption levels are different according to the chemical structure of the phenolic compound. Phenolic structures with an unsaturated bond on their para substituent showed the highest sorption levels. Among wood macromolecules, only lignin had a selective capacity for sorption for phenolic compounds, indicating the importance of this macromolecule in the sorption process. Molecular analysis, by FTIR and NMR identified the interactions between vinylphenol derivates and lignin, suggesting that this compound is sorbed by a chemisorption mechanism, wherein the vinyl function engages in a polymerization reaction with monolignol units of lignin. Because this work utilized different approaches, it offers a more complete picture of the sorption mechanisms of wine phenolic compounds by oak wood
Frias, de Albuquerque Mariana. "Étude paramétrique d'un procédé d'imprégnation des bois feuillus". Master's thesis, Université Laval, 2021. http://hdl.handle.net/20.500.11794/68633.
Texto completoWood is a renewable resource that has been used as a material in appearance products for years. Despite its superior mechanical resistance, different modification processes have been developed to enhance the hardness of wood and make it an even more durable material. Impregnation using monomers is a promising modification method, given its cost and availability. This process is currently being implemented to produce wood polymer composites (WPC), which can have modified and improved physical qualities compared to an untreated wood product. Industrial development is mostly focused on the production of these composites for many applications such as civil construction, furniture, flooring and sports equipment. Currently, monomer impregnation is carried out by the vacuum-pressure method. The amount of chemical that can be obtained by this method is considered to be high; in some cases, up to 200%. The WPCs produced have improved mechanical properties and greater resistance to water impregnation. However, the impregnation process takes about 1 hour, and the wood must be immersed in the liquid (Bethell’s full-cell process). This can be seen as a waste of both material and time in the process. Previous studies have concluded that performing a monomer impregnation on a hardwood surface using a short vacuum period was successful and could reduce these problems. Therefore, it became necessary to find ways to reduce the time and cost of industrial impregnation. The objective of this work was to evaluate the parameters influencing monomers penetrationin tangential surface samples of yellow birch (Betula alleghaniensis Brit.) and red oak (Quercus rubra L.). The factors analyzed were the viscosity of the monomer formulation, surface temperature, vacuum level applied to the process, sample anatomy, and absorption time. After impregnation, the weight gain of the samples was calculated. The penetration depth of the monomer was calculated using density profiles (for yellow birch samples) and the penetration was visualized using X-ray tomography imaging. The results showed that surface temperature did not influence weight gain for any of the species studied. However, the increase in temperature accelerated the polymerization process of monomeric formulations, which may have limited the increase in chemical retention at higher temperatures. Microtomographic images after the temperature study showed that the impregnation was concentrated near the surface of the samples, i.e., there was no deep penetration of monomers. Subjecting the samples to a short vacuum level increased the weight gain of the samples compared to impregnation under atmospheric pressure. The driving force behind the monomer penetration was the pressure difference imposed by the vacuum level, which overcame capillary action. For Yellow birch samples, the variation of vacuum levels did not significantly affect the weight gain results, possibly due to the size of its pores. For red oak, the vacuum level was significant, and the chemical retention increased with pressure differential. Microtomographic scans showed a more controlled and uniform distribution of the monomers. Finally, the absorption time after vacuum relaxation was significant in monomer retention. The contact of both species with the formulations for more than 5 minutes significantly increased monomers intake. X-ray scans showed that for both species, more pores were filled. The depth of penetration did not increase so much for yellow birch but increased for red oak. Thus, it can be said that a longer absorption time allows capillarity to continue filling the empty vessels of the wood until the internal pressure is equal to the external pressure. This research may encourage future work to study the feasibility of reducing vacuum pressure cycles in industrial processes. This method can enable hardening the surface of interest of a wood product in a controlled manner, with reduced costs and avoid wasting of impregnation materials.
Mellouki, Bendim'Red Naoual. "Thyllose et perméabilité du bois des chênes français de tonnellerie". Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0018.
Texto completoThe tightness of wood sessile and pedunculate oaks in the longitudinal direction depends on the quantity and quality of tylosis. In recent years, an unusually high rate of leak in barrels made was noted. An experimental study was conducted on two barrels leaking and leakage observed resulted in a fine exploration of the pathways of the colored liquid inside the defective staves. We were able to connect a low tylosis with migration of liquid that can be done along the length of a stave. In addition, a special production of staves was conducted to understand the influence of the height in the tree, the cambial age, watering and curing parameters of staves (time, position in the stack) on the permeability and thyllose. It was necessary to develop a method to quantify the tylosis. Two methods are used: The first observation is based on anatomical and ownership of vessels not blocked or partially blocked by tylosis to let light through. The second is to take measurements of air permeability on cylindrical cut in the longitudinal direction. Infradensity of the samples were also measured. The observations in Scanning Electron Microscopy were used to examine the fine structure of tylosis and the presence of spores and mycelial hyphae. The results are analyzed with a software statistical processing of data. We were able to determine the adverse effect of microbiological growth, especially fungi, the longitudinal permeability and the amount of tylosis timber if too long maturation
Martin, Frédéric. "Influence des substances extractibles sur le comportement photochimique du bois de chêne : propriétés antioxydantes de ces composés". Nancy 1, 1996. http://www.theses.fr/1996NAN10200.
Texto completoLe, Floch Alexandra. "Les polysaccharides et les ellagitanins du bois de chêne : influence sur la qualité sensorielle des vins". Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0369/document.
Texto completoIt is widely accepted that alcoholic beverages quality depends on their ageing in premium quality oak wood. Oak wood selection and maturation are essential steps in the course of barrel fabrication. Given the existence of many factors involved in the choice of raw material and in natural seasoning of oak wood, it is very difficult to determine the real impact of seasoning and selection factors on oak wood composition. A sampling was done to study the evolution of oak wood chemical composition during four seasoning steps: non matured, 12 months, 18 months and 24 months. For this sampling, three selection factors were taken into account: age, grain type and the Polyphenolic Index measured by Oakscan®. Besides extractables (~10%), three polymers constitute the main part of oak wood: cellulose, hemicelluloses and lignins. These compounds may undergo hydrolysis or chemical reactions during cooperage processes, especially during heat treatment, which release some aromatic compounds or aromatic precursors having a genuine sensorial interest on wine aged in barrel or in contact with oak products. To date, no studies revealed a link between the proportions of these compounds in oak wood and the chemical and sensorial impact in wines ageing with oak wood. Our study showed that the proportions of these compounds evolved significantly during oak wood seasoning and the results highlighted the impact of selection factors. Respectively, extractables, lignins, hemicelluloses and cellulose proportions were mostly for non-matured, 12 months, 18 months and 24 seasoning months. The development of a test plan with a Merlot wine from a second oak wood sampling, using similar modalities as the previous test plan allowed the evaluation of oak wood seasoning impact on the chemical composition of a wine ageing with oak wood pieces. Results showed a lowering of 8% in ellagitannins content of wine between 12 and 24 months modalities. An impact on volatile composition in wine has also been established: furanic aldehydes were positively correlated with a long maturation time (18 and 24 months), whereas phenolic aldehydes were positively correlated with a shorter seasoning time (12 months). Our results highlighted also the impact of selection factors on wine chemical composition. Sensorial analysis on this Merlot wine led to significant differences detected by the panel between 12 and 24 seasoning modalities, but not between 18 and 24 months modalities with triangular tests. Sensorial profiles were also established to attempt to associate the differences detected to one or more descriptors. For this test, results highlighted the difficulty for the panel to make a significant difference between 12 and 24 months modalities. However they contribute to explain the differences demonstrated with triangular tests for some seasoning modalities: toasted, bitterness, astringency, roundness and sweet perception
Schmitt, Emmanuel. "Contribution au Système d'Information d'un Produit « Bois ». Appariement automatique de pièces de bois selon des critères de couleur et de texture". Phd thesis, Université Henri Poincaré - Nancy I, 2007. http://tel.archives-ouvertes.fr/tel-00170106.
Texto completoSchmitt, Emmanuel. "Contribution au Système d’Information d’un Produit « Bois » : appariement automatique de pièces de bois selon des critères de couleur et de texture". Thesis, Nancy 1, 2007. http://www.theses.fr/2007NAN10079/document.
Texto completoOur works concern the study of a fuzzy sensor adapted to the color identification on wooden boards. The proposed method aims particularly to take into account the human subjectivity concerning the color perception and to provide results in the user vocabulary. The application field (timber industry) imposes certain constraints. Indeed, the color classes are not separated (non-strict boundaries) and are represented with few samples. Then, it results from it, imprecisions and uncertainties in the output class definition. After a state of the art on the techniques of image processing, of pattern recognition, and on the structure of intelligent sensors, our works are exposed along two axes: from the sensors to the measurements, and from the measurements to the decision. Firstly, we have evaluated and corrected the perturbations linked to the environment of the sensor (temperature, ageing, …). Then, we have determined the most discriminating colorimetric space, and generated the characteristic vector composed of interpretable attributes allowing to identify the colors. From these data, we have developed the Fuzzy Reasoning Classifier based on a fuzzy linguistic rule mechanism aggregating conjunctive rules according to the Larsen model. Finally, for the multi-sensor systems, a fuzzy operator of data merging is used. The use of this fuzzy sensor has shown the good behaviour of the system compared to the real-time industrial constraints, and an improvement of 10% of the recognition rates
Schmitt, Emmanuel. "Contribution au Système d’Information d’un Produit « Bois » : appariement automatique de pièces de bois selon des critères de couleur et de texture". Electronic Thesis or Diss., Nancy 1, 2007. http://www.theses.fr/2007NAN10079.
Texto completoOur works concern the study of a fuzzy sensor adapted to the color identification on wooden boards. The proposed method aims particularly to take into account the human subjectivity concerning the color perception and to provide results in the user vocabulary. The application field (timber industry) imposes certain constraints. Indeed, the color classes are not separated (non-strict boundaries) and are represented with few samples. Then, it results from it, imprecisions and uncertainties in the output class definition. After a state of the art on the techniques of image processing, of pattern recognition, and on the structure of intelligent sensors, our works are exposed along two axes: from the sensors to the measurements, and from the measurements to the decision. Firstly, we have evaluated and corrected the perturbations linked to the environment of the sensor (temperature, ageing, …). Then, we have determined the most discriminating colorimetric space, and generated the characteristic vector composed of interpretable attributes allowing to identify the colors. From these data, we have developed the Fuzzy Reasoning Classifier based on a fuzzy linguistic rule mechanism aggregating conjunctive rules according to the Larsen model. Finally, for the multi-sensor systems, a fuzzy operator of data merging is used. The use of this fuzzy sensor has shown the good behaviour of the system compared to the real-time industrial constraints, and an improvement of 10% of the recognition rates
Giraud, William. "Étude physico-chimique de l'interface bois-vin pendant l'élevage en barriques". Toulouse 3, 2009. http://thesesups.ups-tlse.fr/2372/.
Texto completoPhysico-chemical processes occur during wine ageing and make its control difficult. The goal of this work is to offer to barrelmakers some theoretical elements and physico-chemical methods to characterize oak wood. A theoretical part describes some profiles of concentration of some molecules submitted to diffusion and adsorption in wood. Six tools for characterization of wood, its surface and its chemical composition are then presented. A first group concerns the determination of porosity by impregnation of hexadecane, the definition of acid and base components from contact angle measurements and the estimation of pore sizes deducted from speed of capillary ascending. A second group is relative to electrochemistry with the study, in a model solution, of 28 molecules ; the definition of a global antioxidant activity and a global aldehydic index; electrochemical measurements are also realized directly on wood surface with an original sensor
Voinot, Damien. "Caractérisation des composés organiques volatils issus du séchage du bois. Application au chêne rouge et au pin gris". Thesis, Université Laval, 2007. http://www.theses.ulaval.ca/2007/24308/24308.pdf.
Texto completoThis study focuses on the characterization and quantification of the volatile organic compounds (VOC) emitted during the dehumidification drying of red oak and the conventional drying of Jack pine at medium temperature. The methods used in this study were NCASI IM/CAN/WP-99.02, NCASI MD-99 and US-EPA 25A. We also employed a new technique for characterizing the volatile molecules: Headspace-SPME, which enables the laboratory simulation of pine and oak drying. Jack pine showed very high VOC emission rates: 2,24 gVOC/kgODW. The main monoterpenes identified among the volatiles released during the drying of jack pine were: alpha-pinene, beta-pinene and 3-carene. The main polar compounds collected from jack pine were methanol, acetaldehyde and methyl acetate, and the main polar compounds collected from red oak were acetic acid (vastly predominant), methanol and ethanol. Headspace-SPME enabled the identification of several volatile polyphenols (eugenol, etc.) released by red oak, as well as the identification of bioactive sesquiterpenes (such as alpha-humulene and caryophyllene) released by Jack pine.
Winstel, Delphine. "Recherches sur les composés du bois de chêne modulant la saveur des vins et des eaux-de-vie". Thesis, Bordeaux, 2019. http://www.theses.fr/2019BORD0409.
Texto completoDuring barrel aging, wines and spirits undergo organoleptic changes caused by the release of aroma and taste molecules. While the key aromatic compounds released from oak wood have been identified, the bitter and sweet molecular determinants remain largely unknown. The first objective of this work was to bring new insights on the families of molecules already identified in oak wood: lignans and coumarins. First, a significant impact of (±)-lyoniresinol on spirits bitterness has been demonstrated. Then, sensory analysis showed the contribution of six coumarins to bitter taste of wines and spirits by synergistic effect. Fraxetin was identified for the first time in all three matrices of the study. In the second part of this work, the contribution of oak wood toasting to wine sweet taste has been studied, which allowed to confirm and to interpret empirical observations. Indeed, the aim of this study was to isolate new taste-active compounds, according to two different methods. For the first one, a fractionation protocol of oak wood extracts has been established. Separation techniques coupled with gustatometry allowed the purification of eleven taste-active compounds. Their identification has been carried out by HRMS and NMR. For the second method, a targeted approach has been used following a metabolomic screening by HRMS on several eaux-de-vie of Cognac. Two new taste-active molecules have been purified. These new markers have been quantified in several oak wood extracts, wines and spirits. The influence of oenological parameters on its content has been studied
Bloem, Audrey. "Activités glycosidases chez Œnococcus œni : importance dans la libération de la vanilline à partir de bois de chêne". Bordeaux 2, 2005. http://www.theses.fr/2005BOR21291.
Texto completoLactic acid bacteria (LAB) conducting the malolactic fermentation (MLF) have a significant influence on the stability and organoleptic quality of wine. The MLF can be performed in barrels and the influence of this practice on the modification of the levels of oak wood volatile compounds is also studied in this work. We showed that Oenococcus oeni was able to increase the levels of oak wood volatile compounds during the malolactic fermentation. This release is important, particularly for vanillin when LAB metabolism is the most active. Enrichment persists during the ageing and contributes to the aromatic complexity of wine. This release indicates the presence of precursors in oak wood and the production of enzymes by this species that affect vanillin formation. Several mechanisms were considered and the presence of glycosylated precursors were investigated, as well as vanillin for other oak wood compounds such as phenolic aldehydes and also eugenol, isoeugenol or the whiskylactone. The effect of glycosidases on the released vanillin was studied and this aldehyde is present in wood extracts in monoglycosidic forms where the major glycones are the arabinose and the xylose. The LAB have widespread glycosidase activities within the species O. Oeni but with a great variability. This activity causes the release of vanillin during MLF. Lastly, the purification of the α-L-arabinosidase involved in the hydrolysis of vanillin in this species was initiated
Roque, Ugulino De Oliveira Bruna. "Effets des procédés d'usinage de finition sur les propriétés de surface, la performance d'un vernis et l'émission de poussières du bois de chêne rouge". Doctoral thesis, Université Laval, 2016. http://hdl.handle.net/20.500.11794/27028.
Texto completoCoating performance on wood could be affected for different aspects including the manner in which the surface is prepared. Sanding is often used to prepare wood surfaces prior to finishing. However, this process can generate large amount of wood dust. Thus, the effects of machining processes on surface properties, coating performance and dust emission were investigated in an attempt to determine the most appropriate methods for surface preparation of red oak wood. In a first part of this project, surface properties and coating performance were evaluated on machined surfaces obtained by sanding, peripheral and helical planing as well as oblique cutting. Surface quality was assessed through roughness, scanning electron micrographs and wettability analyses. The performance of a solvent-borne coating was measured by adhesion strength before and after an accelerated aging. The results showed that sanding induced high surface roughness and fibrillation level as well as high wettability and pull-off strength after aging than other processes. Peripheral planing samples showed a certain cell-wall fibrillation, and intermediate surface roughness and wetting properties. Helical planing samples presented intermediate surface roughness. On the other hand, oblique cutting showed similar loss in adhesion to sanding. This process generated smooth surfaces with intermediate roughness and wettability. Based on the results, sanding with a single stage program P100-grit at 7 m/min feed speed, peripheral planing with a rake angle of 25° and a wavelength of 1.0 mm, helical planing with a wavelength of 1.0 mm, and oblique cutting with an oblique angle of 15° were the best machining conditions for each process. In a second part of the study, the effect of cutting parameters on dust emission and surface roughness was studied during the helical planing of red oak wood. Results showed that dust emission decreased significantly when lower cutting depth and higher average chip thickness was used. However, samples cut at the highest average chip thickness showed higher values of surface roughness. This implies that if a smoother surface is required, an intermediate feed speed should be used in order to decrease surface roughness without exposing woodworker to high levels of wood dust. Moreover, dust emission for each particle size fraction can be estimate through the models developed as a function of average chip thickness and cutting depth.
Botosso, Paulo Cesar. "Une méthode de mesure du retrait microscopique du bois : application à la prédiction du retrait tangentiel d'éprouvettes de bois massif de Sapin pectiné (Abies alba Mill.)". Nancy 1, 1997. http://docnum.univ-lorraine.fr/public/SCD_T_1997_0001_BOTOSSO.pdf.
Texto completoPrida, Andrei. "Caractéristiques chimiques des bois de chêne français et étrangers destinés à la tonnellerie : leur influence sur l'élevage des vins et le viellissement des eaux-de-vie". Montpellier, ENSA, 2004. http://www.theses.fr/2004ENSA0005.
Texto completoCharrier, Bertrand. "Les discolorations brunes du chêne apparaissant pendant le séchage artificiel : étude fondamentale et mise en place de techniques de prévention". Vandoeuvre-les-Nancy, INPL, 1992. http://www.theses.fr/1992INPL116N.
Texto completoZahri, Sofia. "Analyse quantitative et qualitative des substances chimiques responsables des durabilités naturelle et conférée des bois de chêne européen (Quercus robur et Quercus petraea) et de pin maritime (Pinus pinaster) par la spectroscopie dans le proche infrarouge". Pau, 2007. http://www.theses.fr/2007PAUU3024.
Texto completoNear infrared spectroscopy (NIRS), in conjunction with multivariate analysis, could be a suitable technique to assess chemical substances responsible of natural and conferred wood durability. For natural durability, European oak extractives were studied by using NIRS. First, near infrared (NIR) spectra were collected from both axial and radial planes of solid oak samples. Then, these planes were cut and ground in order to take NIR spectra from oak sawdust, before and after phenol extraction. Concerning the study of artificial durability, wood strips were selected from heartwood and sapwood of Maritime pine and prepared for impregnation by two groups of active components and at three concentrations. The first group concerns industrial wood preservatives which contain boric acid, copper, cypermethrin, IPBC, permethrin, propiconazol, and tebuconazol. The second one includes pure solutions prepared with boric acid, cypermethrin, IPBC, permethrin, propiconazol, and tebuconazol. Calibrations were developed by using Partial Least Squares (PLS) technique. Principal component analysis (PCA) was applied to separate between treated and untreated Maritime pine wood and also between the different preservation products. NIR information was enhanced by using the pre data processing procedures: first and second derivatives (1st D, 2nd D), Multiplicative Scatter Correction (MSC), Standard Normal Variate (SNV) and also their combinations: 1st D. MSC, 1st D. SNV, 2nd D. MSC and 2nd D. SNV. PLS models displayed excellent correlations between calculated and predicted values by NIRS, accompanied by high correlation coefficient (r²) and weak calibration and prediction error (SEC, SEP). This study illustrates that the NIRS technique when it is used in conjunction with multivariate analysis could give reliable, quick and non-destructive assessment of European oak extractives content and the retention Maritime pine preservation products. Our findings show also the potential of NIRS technique to distinguish, on one hand between treated and untreated Maritime pine wood and on the other hand between different industrial preservation products
Côté, Nelson. "Composite chêne-polypropylène : influence de la concentration en bois et en agent liant sur les propriétés physico-mécaniques du matériau". Master's thesis, Université Laval, 2003. http://hdl.handle.net/20.500.11794/36802.
Texto completoQuébec Université Laval, Bibliothèque 2019
Ramirez, Ramirez Gabriela. "Etude de la sorption des composés d'arôme du vin par le bois de chêne en système modèle d'élevage en fûts". Dijon, 2002. http://www.theses.fr/2002DIJOS062.
Texto completoMichel, Julien. "Classification et influences des polyphénols du bois de chêne sur la qualité sensorielle des vins (Application du procédé OakScan®)". Thesis, Bordeaux 2, 2012. http://www.theses.fr/2012BOR21989/document.
Texto completoDuring the wine aging with oak wood, some compounds with interesting organoleptic properties such as ellagitannins (i.e., vescalagin, castalagin, roburins A, B, C, D, E and grandinin) are extracted. The ellagitannins concentrations in oak wood and wine are highly variable and their extractions kinetic during the aging as well as their organoleptic impacts on wines are poorly known and still unclear. In order to classify each stave according to their polyphenolics index (IP) before making the barrels, an infrared system (NIRS), Oakscan®, was develop by the tonnellerie Radoux. Our aim was to study the influence of this wood classification on the wines molecular composition and organoleptic properties.In the first place, the NIRS oak staves classification has been confirmed by the determination of the total ellagitannins concentration as well as the specific levels of each ellagitannins molecule by HPLC-UV-MS. A high variability of the ellagitannins level in wood between 5.95 ± 0.30 and 32.91 ± 0.98 mg ellagic acid equivalent/g of dry wood was observed. Furthermore, the wood infrared classification is correlated with chemical analyzes (p < 0.02%) and allow the production of barrels with different IP (IP: 11, 12, 16, 21, 26, 30, 35, 36, 39, 40, 41, 50, 51, 53, 62, 67 et 70).In a second place, some wines were aged in the classified barrels. The ellagitannins levels show the oak wood classification influences (p < 5%). Indeed, the first months of aging, the ellagitannins concentration increased until a maximum was obtain . Indeed, this maximum concentration in wine aged in barrel manufactured with the wood richer in ellagitannins was higher and latter (2.30 ± 0.05 after 4 months and 11.56 ± 0.31 mg ellagic acid equivalent/L of wine after 12 months respectively for the IP 21 and IP 70 barrels). After this maximum, a slow decrease of the ellagitannins level was observed. The influences of grain and toasting were also analyzed. The aromatics compounds solubilization of classified oak wood by Oakscan® show that the furanic aldehydes levels (furfural, alcool furfurylique et 5-méthylfurfural) and the syringol involved in the smocked/toasted aromas were correlated with the NIRS classification and the wood IP. So, a wine aged in contact with wood richer in polyphenols compounds was describe as more smocked/toasted. Nevertheless, the toasting intensity (which formed these compounds by thermo-degradation of hemicelluloses and lignins) plays a major role on their concentrations. Moreover, organoleptic properties of the wines aged with oak wood (barrels, staves) at 6, 12, 18 or 24 month and tested by trained judges were significantly impacted by the IP barrels. In fact, wine with the highest ellagitannins level was significantly described with a higher woody, smoked/burned and spicy in nose. In mouth, the bitterness and the astringency were significantly higher in wine containing the highest ellagitannins level. Whereas, the wine fruity aroma, in nose and mouth, was generally descript as lower in wine aged with the barrel with the IP higher.The influences of wood classification, in relation with the grain and the IP, on the red wine oxygen consumption after being put into barrels were analyzed with a new no invasive method. The results show that 96% of the oxygen in wine at T0 was consumed after 8 days. Significant differences (p < 0.01%) between the oxygen consumption speed and the barrel IP or the grain were observed. The oxygen consumption speed increase with correlation of barrel IP or the size of grain. These results allows the utilization of method not empirical and reliable method to select oak wood regarding their grain or their ellagitannins concentration in order to be able to produce oak barrels classified by means of our results to give organoleptic properties controlled to the wine
Baton, Franck. "Effets de la carbonisation oxygénée sur le signal isotopique (δ13C) du bois : vers une dendroclimatologie isotopique sur charbons archéologiques". Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066236/document.
Texto completoArcheological charcoals are used for reconstructing past woodland vegetation and the related historical forest practices. Charcoals δ13C are used for paleoclimate reconstructions. To better constrain the use of δ13C, we investigated the effect of oxygenated carbonization on ring scale δ13C variations in oak wood. Results showed a significant decrease of δ13C values after carbonization. This effect, however, is highly variable according to the wood compartment considered: heartwood, sapwood, earlywood, or latewood. Carbon content measurements do not exhibit the same variations along oxygenated carbonization as observed with δ13C. Therefore, the use of carbon content for evaluating carbonization effects on δ13C, which is proposed by some authors, is not appropriate. Interannual and seasonal δ13C variations, however, are not significantly affected by oxygenated carbonization. Thus, paleoclimate reconstruction from charcoals δ13C appears possible. To test both ring scale variations, archeological charcoals were sampled from a climatically well documented Neolithic site of Chalain. Several dendro-anthracological parameters (latewood proportion, duraminization, charcoal-pith distance estimation) were characterized for a better understanding of δ13C variations, in order to integrate historical woodland practices and the climatic interpretations. Charcoal tree-rings exhibited width and δ13C significantly different between the two studied periods, in agreement with previously inferred climatic difference. Intra-ring δ13C suggested that the cool and moist climatic period also corresponded to higher seasonal contrast than the dryer climatic period. Dendro-anthracological parameters allow better understanding of δ13C variations between wood compartments and provide information on past woodland exploitations. To conclude, oxygenated carbonizations induce a decrease in wood δ13C values, but do not prevent the paleoclimate interpretations of δ13C variations in archeological charcoals
Badel, Eric. "Détermination des propriétés élastiques et du retrait d'un cerne annuel de chêne dans le plan transverse : description de la morphologie, mesures des propriétés microscopiques et calculs d'homogénéisation". Nancy, ENGREF, 1999. http://www.theses.fr/1999ENGR0064.
Texto completoBaton, Franck. "Effets de la carbonisation oxygénée sur le signal isotopique (δ13C) du bois : vers une dendroclimatologie isotopique sur charbons archéologiques". Electronic Thesis or Diss., Paris 6, 2017. http://www.theses.fr/2017PA066236.
Texto completoArcheological charcoals are used for reconstructing past woodland vegetation and the related historical forest practices. Charcoals δ13C are used for paleoclimate reconstructions. To better constrain the use of δ13C, we investigated the effect of oxygenated carbonization on ring scale δ13C variations in oak wood. Results showed a significant decrease of δ13C values after carbonization. This effect, however, is highly variable according to the wood compartment considered: heartwood, sapwood, earlywood, or latewood. Carbon content measurements do not exhibit the same variations along oxygenated carbonization as observed with δ13C. Therefore, the use of carbon content for evaluating carbonization effects on δ13C, which is proposed by some authors, is not appropriate. Interannual and seasonal δ13C variations, however, are not significantly affected by oxygenated carbonization. Thus, paleoclimate reconstruction from charcoals δ13C appears possible. To test both ring scale variations, archeological charcoals were sampled from a climatically well documented Neolithic site of Chalain. Several dendro-anthracological parameters (latewood proportion, duraminization, charcoal-pith distance estimation) were characterized for a better understanding of δ13C variations, in order to integrate historical woodland practices and the climatic interpretations. Charcoal tree-rings exhibited width and δ13C significantly different between the two studied periods, in agreement with previously inferred climatic difference. Intra-ring δ13C suggested that the cool and moist climatic period also corresponded to higher seasonal contrast than the dryer climatic period. Dendro-anthracological parameters allow better understanding of δ13C variations between wood compartments and provide information on past woodland exploitations. To conclude, oxygenated carbonizations induce a decrease in wood δ13C values, but do not prevent the paleoclimate interpretations of δ13C variations in archeological charcoals
Guichoux, Erwan. "Prédiction de la qualité des bois de chêne pour l’élevage des vins et des alcools : comparaison des approches physicochimiques, sensorielles et moléculaires". Thesis, Bordeaux 1, 2011. http://www.theses.fr/2011BOR14246/document.
Texto completoMost of aromatic compounds in wine are directly induced during maturation by the contactwith oak wood. For example, whisky-lactone, the most important aromatic compound,which gives a coconut and woody taste, is easily detected and appreciated by consumers.Quercus petraea and Q. robur, the two major European oak species used for wine maturation,have very contrasted aromatic patterns, especially for whisky-lactone. Identifying the speciesused for cooperage will facilitate the maturation process, for instance by providing winerieswith more homogenous batches of barrels. The objective of our study is to characterize theoak species directly from dry wood, using molecular markers that will be applicable in anindustrial context. Unfortunately, dry wood is a dead tissue in which DNA is highlydegraded and difficult to access. To optimize DNA recovery from dry wood, we developed aquantitative PCR protocol based on chloroplast DNA to evaluate the efficiency of DNAisolation protocols. We identified and developed molecular markers (SSRs and SNPs)adapted to dry wood that are particularly diagnostic. Using an optimized DNA isolationprotocol and these powerful markers, the species identity from wood samples dried duringtwo years could be successfully characterized. Using 262 SNPs highly differentiated betweenthe two species, we also demonstrate that genes under selection (outlier loci) haveoutstanding power to delimitate the two oak species and provide unique insights on intraandinterspecific gene flow, whereas genes lacking such a signature (putatively neutral loci)provide little or no resolution
Evrat, Christophe. "Étude et réalisation d'un système de vision adapté à l'industrie du bois : Application à la classification automatique de frises en chêne par couplage avec un capteur micro-ondes". Nancy 1, 1989. http://www.theses.fr/1989NAN10016.
Texto completoMazet, Jean-François. "Couleur et qualité des placages de chêne et étude de leur comportement photochimique". Nancy 1, 1988. http://www.theses.fr/1988NAN10393.
Texto completoAubert, Monique. "Recherche de relations entre caractéristiques simples du bois de chêne rouge (quercus rubra l. ) mesurées par voie non destructive et deux de ses propriétés technologiques : Stabilité dimensionnelle des planches et qualité des placages d'ébénisterie". Nancy 1, 1987. http://www.theses.fr/1987NAN10128.
Texto completoFaydi, Younes. "Classement pour la résistance mécanique du chêne par méthodes vibratoires et par mesure des orientations des fibres". Thesis, Paris, ENSAM, 2017. http://www.theses.fr/2017ENAM0051/document.
Texto completoHardwoods are the majority in France, with a substantial amount of small, low grade oaks. This resource could be an alternative of typical construction materials. However, mechanical properties can change a lot depending on timber defects. Thus, it is necessary to verify the good quality of each board in order it can be used in structural applications. The efficiency of grading methods is one of principal challenges to promote the use of oak in structures. The present work aims to provide new grading machine solutions relative to low grade oak which could replace the traditional and downgrading method based on visual sorting by an operator.Indeed, two models have been developed during this thesis, based on nondestructive measurements following by destructive tests to validate them. The first one is an analytical model based on grain angle scanning measurements. From grain angle data maps, local values of modulus of elasticity and resistance were computed, then the global mechanical properties were computed. The second one is a statistical model based on the analysis of longitudinal and transversal vibrational measurements. The results show that the longitudinal vibrational method based on the first longitudinal eigen frequency, which is mostly employed in softwood industry, is not suited for oak grading. However, the efficiency of the methods based on transversal vibrations is pretty good but it needs additional efforts for industrial application. In this work, the model based on grain angle scanning offer the best and the more robust grading efficiency for all grades
Daya, Abdelmajid. "Études des contraintes de croissance des arbres sur pied d'eucalyptus grandis et du chêne vert : caractérisation et valorisation sous forme de bois collé". Metz, 2006. http://docnum.univ-lorraine.fr/public/UPV-M/Theses/2006/Daya.Abdelmajid.SMZ0615.pdf.
Texto completoThe aim of this study is to measure the growth stress indicators (GSI) of the wood of grown Eucalypti and holm oak and to determine the technological properties for the valorization of these two species in the form of glued wood. Three trees of grown Eucalypti and holm oak were studied. Tensile specimens with massive wood and glued wood (end to end and in bevel), and DCB specimens with massive wood and glued wood were prepared. The quality of the assembly is treated by a probabilistic model based on the Weibull's statistical approach permitting to predict the reliability of the glued systems. The GSI, measured in the periphery of the trees, characterize the state of the wood formed in the very last years. The GSI distribution revealed generally that these two species have different behaviours. The grown Eucalyptus and the holm oak present a high nervousness. These obtained characteristics allowed us to classify them in a hard to half-hard wood, nervous, of strong shrinkage and an average rigidity. The massive wood presents a brittle behaviour with a fracture stress of the holm-oak twice bigger than that of the grown eucalyptus , although the glued wood (end to end or beveled) presents a ductile behaviour with a fracture stress almost the same for these two types of assembly. The Weibull coefficient m of the massive wood of these two species is weaker than that of the glued wood. The measurement of the restitution rate of the energy (toughness) of the massive wood and glued wood of grown eucalyptus and holm-oak has been experimentally achieved using the compliance method. The massive wood of these species is stronger than the glued wood. This latter has a higher toughness than that of the glued polyurethane. The average value of the experimentally determined toughness is very close to that calculated by the finite element code CASTEM 2000, which is greater than those found by ASTM and two embedded beams methods. In the massive wood, the crack initiates in the plan of low strength and the types of fracture observed during its propagation are intercellular and transcellular. In the glued wood the crack starts in the glue joint for the holm-oak, and both in the glue and wood for the grown eucalyptus. Whereas, its propagation is always adhesive for the holm-oak and mixed for the grown eucalyptus (alternately in wood and glue)
Arramon, Gilles. "Les triterpènes et lignanes des bois de chêne européen Quercus robur L. Et Quercus Petraea Liebl. : quantification et apports qualitatifs aux eaux de vie d'Armagnac". Bordeaux 2, 2001. http://www.theses.fr/2001BOR20882.
Texto completoPurba, Citra Yanto Ciki. "Characterization and valorization of secondary quality hardwood as structural material". Thesis, Paris, AgroParisTech, 2019. http://www.theses.fr/2019AGPT0002/document.
Texto completoTo improve the value of secondary quality hardwood, it is important to understand its wood properties and optimize its mechanical properties. The variability of some structural, physical and mechanical properties of wood from beech and oak trees issued from thinning was studied. Logs from these trees were rotary peeled in three different veneer thicknesses (2.1, 3, and 4.2 mm). Veneer quality was assessed by measuring the veneer knot proportion and checking properties. The mechanical properties of LVL (laminated veneer lumber) made from these veneers were measured using the static and dynamic method. Juvenile wood in both species is concentrated in a very small area near the pith thus there will be no or low part juvenile wood peeled. The wood mechanical and physical properties of both species were strongly influenced by the wood density. The 3 mm thick veneer provided the optimal mechanical properties for LVL for both species. Such mechanical properties are comparable to LVL made with other hardwood species. The internal veneer provided LVL with higher density, but lower mechanical properties as a result of its higher proportion of knots
Guilley, Edith. "La densité du bois de chêne sessile (Quercus petraea Liebl.) : Elaboration d'un modèle pour l'analyse des variabilités intra- et inter-arbre; Origine et évaluation non destructive de l'effet « arbre »; Interprétation anatomique du modèle proposé". Phd thesis, ENGREF (AgroParisTech), 2000. http://pastel.archives-ouvertes.fr/pastel-00002809.
Texto completoKlumpers, Johannes. "Le déterminisme de la couleur du bois de chêne : Etude sur les relations entre la couleur et des propriétés physiques, chimiques et anatomiques ainsi que des caractéristiques de croissance". ENGREF, 1994. http://www.theses.fr/1994ENGR0033.
Texto completoBADEL, Eric. "Détermination des propriétés élastiques et du retrait d'un cerne annuel de chêne dans le plan transverse : description de la morphologie, mesures des propriétés microscopiques et calculs d'homogénéisation". Phd thesis, ENGREF (AgroParisTech), 1999. http://tel.archives-ouvertes.fr/tel-00005709.
Texto completola morphologie qui définit les éléments structuraux (rayons ligneux, fibres) et leur distribution spatiale au sein du volume représentatif du matériau. Cette description est obtenue grâce au développement d'un dispositif d'imagerie numérique basé sur le principe de l'atténuation d'un rayonnement X.
les propriétés microscopiques des principaux éléments constitutifs du plan ligneux du chêne. Dans le cadre de cette étude, où les propriétés mécaniques et de retrait sont au centre de nos préoccupations, deux types d'échantillons microscopiques (quelques centaines de micromètres) sont préparés au sein de chacun des constituants :
- les premiers sont sollicités en traction grâce à une machine d'essai placée sous un microscope. La comparaison d'images de la structure à différents niveaux de stress permet d'accéder à des propriétés élastiques (modules d'Young, coefficients de Poisson) pour chacun des tissus considérés.
- les seconds sont disposés dans une chambre climatique placée au sein du dispositif d'imagerie X précédemment développé. La comparaison d'images réalisées à différents états hydriques permet, sans contact, d'accéder aux coefficients de gonflement des éprouvettes, simultanément dans deux directions.
Enfin l'utilisation d'un outil numérique d'homogénéisation, MorphoPore, permet d'assembler ces connaissances afin de calculer les propriétés macroscopiques d'accroissements annuels. Les images de la morphologie issues du banc d'imagerie X sont alors la base d'un maillage numérique ; les propriétés microscopiques des différents tissus qui y sont injectées étant issues essentiellement des mesures expérimentales.
Les potentialités de l'outil sont présentées au travers de quelques cas. En particulier, cette approche permet de distinguer les influences de paramètres génétiques tel que le plan ligneux, de ceux liés à la croissance de l'arbre tels que la sylviculture ou la station. A titre d'exemple, nous citerons la quantification de l'influence de la vitesse de croissance d'un arbre sur les propriétés mécaniques et de retrait du bois.
Bastard, Alexandre. "Interactions micro-organismes - bois et impact sur les propriétés physico-chimiques du vin : fermentation malolactique par le biofilm de Oenococcus oeni". Thesis, Dijon, 2015. http://www.theses.fr/2015DIJOS069/document.
Texto completoMalolactic fermentation improves wine quality, mainly by decreasing acidity. It is carried out by lactic acid bacteria, mainly Oenococcus oeni. This species is favored for its efficiency and its organoleptic outcome. O. oeni ability to withstand wine stress and to keep its fermentation activity is a subject of major interest.Samples of oak showed that O. oeni adheres to wood and is able to persist for several months in wine. However, in the majority of natural habitats, microorganisms grow attached to a surface, within a structured ecosystem called biofilm. In this form of life, cells benefit from an increased stress resistance.These two properties, adherence to a surface and stress resistance, were studied for O. oeni. Observations by scanning electron microscopy have highlighted biofilm formation by O. oeni. Then, we evaluated the wine stress resilience of O. oeni biofilm. Biofilm is a growing interest in food and biotechnology industries, due to the conservation of its metabolic activity in stressful environment. Therefore, malolactic fermentation with an O. oeni biofilm was monitored in wine. Finally, the influence of O. oeni biofilm on transfers of aromatic compounds between wood and wine was studied.This study is the first characterization of O. oeni biofilm, its wine stress resistance and its fermentation potential
Purba, Citra Yanto Ciki. "Characterization and valorization of secondary quality hardwood as structural material". Electronic Thesis or Diss., Paris, AgroParisTech, 2019. http://www.theses.fr/2019AGPT0002.
Texto completoTo improve the value of secondary quality hardwood, it is important to understand its wood properties and optimize its mechanical properties. The variability of some structural, physical and mechanical properties of wood from beech and oak trees issued from thinning was studied. Logs from these trees were rotary peeled in three different veneer thicknesses (2.1, 3, and 4.2 mm). Veneer quality was assessed by measuring the veneer knot proportion and checking properties. The mechanical properties of LVL (laminated veneer lumber) made from these veneers were measured using the static and dynamic method. Juvenile wood in both species is concentrated in a very small area near the pith thus there will be no or low part juvenile wood peeled. The wood mechanical and physical properties of both species were strongly influenced by the wood density. The 3 mm thick veneer provided the optimal mechanical properties for LVL for both species. Such mechanical properties are comparable to LVL made with other hardwood species. The internal veneer provided LVL with higher density, but lower mechanical properties as a result of its higher proportion of knots
Gaudio, Noémie. "Interactions pour la lumière entre les arbres adultes, les jeunes arbres et la végétation du sous-bois au sein d'un écosystème forestier : application à la régénération du pin sylvestre en peuplement mélangé chêne sessile - pin sylvestre". Phd thesis, Université d'Orléans, 2010. http://tel.archives-ouvertes.fr/tel-00587487.
Texto completoHamada, Joël. "Effet de la variabilité intra et interspécifique du bois sur les procédés de traitement thermique". Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0254/document.
Texto completoIn the context of sustainable development which has seen the introduction of the biocides directive BPD 98/8/CE in the EU, innovative wood preservation practices such as Heat Treatment (HT) become relevant. Wood HT, also termed wood thermal modification, is a physical modification technology by which wood is heated at around 200 °C in an inert atmosphere. The main purpose of the treatment is to improve the biological durability and dimensional stability of wood. Current studies on thermally modified wood (TMW) quality are focusing on treated material, on treatment conditions or on species effect on the end-product characteristics. Relatively little is known about the effect of intrinsic wood properties on its thermal modification. As wood properties vary especially under the influence of human activities through sylviculture, this thesis studied the effect of European oak and silver fir wood density and chemical composition on their thermal modification kinetic. An X rays computed tomography (CT) and densitometer were used to characterize wood samples. Boards were heat-treated by conduction under vacuum using a pilot furnace, whereas sawdust samples underwent thermo-gravimetric analysis under nitrogen. The analysis allowed finding intra- and interspecific variations, especially within growth rings and along radial direction (from pith to bark). Forest management impacted heat modification kinetic of the studied samples, especially in silver fir where fast grown wood was more sensitive to treatment. The finding will be used as additional information to the wood industry which will account for homogeneity of loadings destined to heat treatment
Jafarian, Hoda. "Lighting ambiances and materialities of wood in architecture : a comparative evaluation of the quality of spaces in relation to interior finishes". Master's thesis, Université Laval, 2016. http://hdl.handle.net/20.500.11794/27262.
Texto completoWood is a material often used by architects to enhance the overall ambiance of a space but few research discuss its actual impact on visual impressions and luminous effects. This research studies the influence of wood materialities in relation to creating specific lighting ambiances in architecture. More particularly, it focuses on the impact of decorative wood indoor panels on the creation of daylighting diversity in interior spaces and the potential to improve environmental satisfaction and energy efficiency. The research uses scale models for their accuracy in rendering complex daylighting ambiances in conjunction with the latest imaging technologies to capture and analyze the results. The methodology enables the comparison between different settings of interior spaces created by a selection of wood type materialities: ratio (percentage), color and gloss. Spatial modalities are compared in the presence of direct sunlighting and diffuse skylight conditions since lighting patterns and ambiances differ considerably. The results enable a discussion of ambiances in terms of brightness and contrast, color, as well as the luminous distribution in the space. The research underlines roles of wood materialities to achieve luminous diversity and creating visually comfortable interior ambiances as well as its opportunities to enhance architectural ambiances in relation to light.
Bruand, Stéphane. "Elaboration d'aimants plastoferrites orientés : optimisation des caractéristiques de la poudre magnétique de départ et de la matrice polymère : calcul des circuits magnétiques pour l'obtention de pièces injectées à orientation radiale ou axiale". Grenoble INPG, 1990. http://www.theses.fr/1990INPG0063.
Texto completoGirardclos, Olivier. "Dendrochronologie du chêne (quercus robur, quercus petraea), influences des facteurs stationnels et climatiques sur la croissance radiale, cas des sols hydromorphes et des climats atlantiques : applications paleo-ecologiques aux bois subfossiles du marais de brière (loire-atlantique)". Besançon, 1999. http://www.theses.fr/1999BESA2063.
Texto completoBontemps, Jean-Daniel. "Evolution de la productivité des peuplements réguliers et monospécifiques de hêtre (Fagus sylvatica L. ) et de chêne sessile (Quercus petraea Liebl. ) dans la moitié Nord de la France au cours du XXe siècle". Paris, ENGREF, 2006. http://www.theses.fr/2006ENGR0007.
Texto completoHistorical evolution of forest productivity is investigated for the French main two social broadleaved species – common beech (Fagus sylvatica L. ) and sessile oak (Quercus petraea Liebl. ) – in pure even-aged stands from State forests, with an aim of description and quantification at stand scale. The analysis therefore focuses on dominant height growth, a classical proxy for forest productivity. Using a retrospective approach (stem analysis), increments were sampled from two generations of stands associated in couples to ensure control of site conditions. The evolution of growth rate is estimated by statistical modelling of increments, accounting for the effect of stand developmental stage and site differences between couples. Growth trends were assessed at a regional scale, leading to the constitution of 2 samples for beech (Normandie/Picardie, Lorraine/Alsace) and 4 samples for oak (Normandie, val de Loire, plaine d’Allier, Lorraine/Alsace). The increase in dominant height growth rate is widespread on the territory, although its intensity varies along a longitudinal gradient. Whereas it appears to be more pronounced in the Northeastern area for both species, it remains weak or recent in the Northwestern area. Most of the evolution formed in the second half of the century. The secular increase in dominant height growth rate varies between +20% and +100% in extreme situations and reaches an approximate +50-60% common to both species in Northeastern France when eluding the effect of recent years. A multi-causal determinism is suggested. Faster growth rate evolution in recent decades, together with its organisation in space and the sensitivity of species to trophic conditions, emphasize the possible key role of atmospheric nitrogen deposition in the response to environmental changes
Bontemps, Jean-Daniel. "Evolution de la productivité des peuplements réguliers et monospécifiques de hêtre (Fagus silvatica L.) et de chêne sessile (Quercus petraea Liebl.) dans la moitié Nord de la France au cours du XXe siècle". Phd thesis, ENGREF (AgroParisTech), 2006. http://pastel.archives-ouvertes.fr/pastel-00761239.
Texto completoL'augmentation de la vitesse de croissance en hauteur dominante a un caractère général sur le territoire, structuré selon un gradient longitudinal. Pour chaque essence, elle est plus marquée dans le Nord-Est, tandis qu'elle reste faible ou récente dans le Nord-Ouest. L'essentiel de l'évolution a été acquis dans la seconde moitié du siècle. La progression est ponctuée de crises d'origine climatique, communes ou spécifiques, dont la plus marquée est celle de la décennie 1940. Défavorable au hêtre, la décennie 1990 a été bénéfique au chêne, et explique que l'évolution constatée pour cette essence culmine en fin de siècle à un niveau bien supérieur à celui du hêtre. L'augmentation séculaire est comprise pour les extrêmes entre +20% et +100%, et atteint dans le Nord-Est un niveau commun aux deux essences de +50-60% en excluant la période récente. Dans ce secteur, les évolutions de croissance radiale et en hauteur du hêtre sont similaires. La densité du bois est restée stable. En conséquence, la productivité en biomasse a pu suivre l'évolution estimée sur la hauteur dominante. L'analyse des relations croissance - facteur du milieu permet d'aborder la causalité des changements de productivité, et suggère un déterminisme multifactoriel. Le climat aurait eu jusqu'alors des conséquences essentiellement conjoncturelles. Des effets saisonniers opposés sur la croissance sont de plus possibles. Le caractère récent des évolutions constatées, leur organisation spatiale, conjugués à une sensibilité des essences aux conditions trophiques, font ressortir le rôle clé possible des dépôts atmosphériques azotés dans la réponse aux changements de l'environnement.