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In recent years, significant advancement in the synthesis, characterization and association with different types of polymers, thermoplastics or reactive (thermosetting) systems of ionic liquids with tunable nature (ammonium, imidazolium, and phosphonium) open up new perspectives in the field of polymers, in particular in one of epoxy networks. It has been shown that ionic liquids (ILs) could contribute to host polymers as they can act as nanostructuring agents, interfacial agents of nanofillers (ionic exchanges with lamellar silicates or grafted onto silica nanofillers), or even as reagent intervening on the polymerization mechanism. Thus, enhanced physical behaviors (mechanical, surface, thermal resistance, etc.) which cannot be obtained with conventional approaches could be achieved. Furthermore, according to numerous studies, it has also been shown that organic-inorganic (O/I) objects such as metal-oxo clusters of the POSS® (PolyOligomericSilsexqioxanes) could be incorporated into polymers. In particular, in networks based on epoxy or methacryate, POSS® could act as co-monomer and/or self-assemble as O/I nanostructures in order to confer specific functionalities. This thesis work presents the preparation, characterization and modification of epoxy/amine or epoxy IL/amine by IL-modified POSS® nanoclusters. The first par of this work is dedicated to study the effect of the grafting of imidazolium ionic liquid onto POSS® carrying different organic ligands (isobutyl or phenyl) on the formation of uniform and well-dispersed POSS® nanodomains in the epoxy-amine networks. In the second part, the effect of the nanostructuration of IL-g-POSS®Ph within the epoxy/amine network on the properties, including thermal stability, surface properties, mechanical, and fire behavior will be examined. In the last section, new epoxy IL (ILM/IPD) hybrid O/I networks have been implemented. For this, diepoxyde salts (ILMs) were synthesized and then copolymerized with a diamine hardener (IPD) with or without the presence of POSS®Ph-triol or IL-g-POSS®Ph. Such routes were investigated in order to design flexible epoxy IL hybrid networks (ILM/amine/IL-g-POSS®Ph) exhibiting very interesting and multifunctional properties compared to conventional epoxy networks., Au cours de ces dernières années, des avancées importantes ont été réalisées dans la synthèse, la caractérisation et l’association avec différents polymères, thermoplastiques ou systèmes réactifs (thermodurcissables) de liquides ioniques de nature divers (ammonium, imidazolium ou phosphonium) ouvrent de nouvelles perspectives dans le domaine des matériaux polymères, en particulier celui des réseaux époxyde. En effet, il a été démontré que les liquides ioniques (LI) pouvaient apporter beaucoup aux polymères en se comportant en tant qu’agents nanostructurants, agents interfaciaux de nanocharges (échanges ioniques avec les silicates lamellaires ou greffés sur des nanocharges de silice) ou encore en tant que co-monomères intervenant sur les mécanismes de polymérisation. Des comportements physiques améliorés (mécanique, de surface, de tenue thermique, etc.) peuvent être ainsi obtenus par des approches conventionnelles. Par ailleurs, au cours de nombreuses études, il a été également démontré que des objets organiques-inorganiques (O/I) comme des clusters de type métal-oxo ou POSS® (PolyOligomericSilSexqioxanes) pouvaient être incorporés dans des polymères, en particulier des réseaux de type polyépoxy ou méthacrylates, comme co-monomères et/ou être auto-assemblés sous forme de nanostructures O/I susceptibles de leur conférer des fonctionnalités spécifiques. Ce travail de thèse présente donc la préparation, la caractérisation et la modification de réseaux époxy/amine ou époxy LI/amine avec des POSS® modifiés par des LIs. Dans un premier temps, ce travail est dédié à étudier l'effet du greffage des liquides ioniques d'imidazolium sur des POSS® porteurs de différents ligands organiques (isobutyle ou phényle) sur la formation de nanodomaines POSS® uniformément bien dispersés dans des réseaux époxy-amine. Dans la deuxième partie, l’effet de la nanostructuration des LI-g-POSS®Ph sur les propriétés de réseaux époxy/amine, à savoir leur stabilité thermique, leurs propriétés de surface, leur comportement mécanique et leur tenue au feu sera étudié. Dans la dernière section, de nouveaux réseaux époxy-LI hybride O/I ont été mis en œuvre. Pour cela des sels diépoxydés (LIMs) ont été synthétisés puis co-polymérisés avec un durcisseur diamine (IPD) avec ou sans la présence de POSS®Ph-triol ou LI-g-POSS®Ph afin de concevoir des réseaux époxy-LI hybride (LIM/amine/LI-g-POSS®Ph) souples présentant des propriétés très intéressantes par rapport des réseaux époxy classiques.

At the nanoscale, thermal and vibrational properties are intimately linked and depend on the shape and composition of the material. Thanks to the nanostructuration, nanocomposites allow a better control of the heat transfer. This can be used to improve the performances of thermoelectric generators through a better insulation, but also to improve the heat management in microelectronics application. In this work, the thermal properties of some nanocomposites are studied using atomistic level simulations, thanks to molecular dynamics. In a first part, the focus is laid on nanocomposites composed of an amorphous matrix and crystalline nano-inclusions. The approach separating the propagative and diffusive contribution, developed for amorphous materials, is used. The ballistic contribution where the heat is propagated by plane waves is systematically impacted by the nanostructuration. Whereas affecting the diffusive contribution, that spreads the heat slowly at the nanoscale, is more challenging. This can be done, for instance, through pores or inclusions softer than the matrix but in variable proportions. A second part is dedicated to the study of silicon nanowires, and the impact of amorphization. For this, the transport of energy as a function of frequency in crystalline core amorphous shell nanowire is studied. An amorphous shell causes the apparition of diffusive transport and the decrease in transmission at low frequencies. Then, molecular dynamics are coupled to hydrodynamic heat equations to study the radial distribution of flux in those nanowires. This analysis suggests that the reduction of the thermal conductivity upon the addition of shell cannot be linked solely to modified interface properties, but are rather due to a global effect of the shell on the mean free path of heat carriers. Finally, it is shown that structuration of the amorphous layer in a conical shape can be used to obtain thermal rectification, that is, a spatial asymmetry in thermal transport. This rectification appears to be caused by the perturbation of transmission at low frequencies., À l'échelle nanométrique, les propriétés thermiques et vibratoires sont intimement liées et dépendent de la forme et de la composition des matériaux. Grâce à la nanostructuration, les nanocomposites permettent un meilleur contrôle du transport thermique. Ceci permet notamment d'améliorer les performances des générateurs thermoélectriques en offrant de meilleurs isolants, mais aussi une meilleure gestion de la chaleur dans les composants électroniques. Dans ce travail, les propriétés thermiques de quelques nanocomposites sont étudiées en utilisant des calculs à l'échelle atomiques, par le biais de la modélisation de Dynamique Moléculaire. Dans un premier temps, l'accent est mis sur des nanocomposites constitués d'une matrice amorphe et de nano-inclusions cristallines. L'approche développée pour les amorphes, séparant la partie balistique du transfert thermique qui prend la forme d'onde plane se propageant dans le matériau et la partie diffusive repartissant lentement l'énergie dans le matériau, est mise à profit. La séparation de ces contributions a montré que si la structuration affecte systématiquement la partie balistique, maîtriser l'impact sur le transport diffusif est plus complexe. Celui-ci peut notamment être réduit par la présence de pores ou d'inclusions plus molles que la matrice, mais dans des proportions variables. Une deuxième partie est consacrée à l'étude des nanofils de silicium, et à l'impact de l'amorphisation de ceux-ci. Pour cela, le transport d'énergie en fonction de la fréquence dans des nanofils avec une âme cristalline et une coque amorphe est étudié. La coque amorphe provoque l'apparition d'un transport diffusif et une baisse de transmission aux basses fréquences. Ensuite, la dynamique moléculaire est couplée aux équations hydrodynamiques du transport de chaleur. Ce couplage est mis à profit pour étudier la distribution radiale du flux de chaleur en régime établie dans les nanofils cylindriques avec une couche amorphe régulière. Cette analyse suggère que la réduction de la conductivité thermique due à l'ajout de la coque n'est pas uniquement liée aux changements des propriétés de l'interface, mais plutôt à un effet global de la coque amorphe sur le libre parcours moyen. Finalement, la structuration en cône de la couche amorphe est utilisée pour induire une rectification thermique, c’est-à-dire une asymétrie spatiale dans le transport thermique. Cette rectification semble être due à la perturbation de la propagation des porteurs de chaleur à basses fréquences.

This study examines the evolution of the functional properties of two hemp concretes formulated with two different binders over 2 years in different environmental conditions. Stable environmental conditions (50% RH - 20°C) have been applied to hemp concretes to obtain the reference aging AREF. An accelerated aging process AWD is chosen, consisting of cycles of wetting and drying. In relation to the reference aging, no significant variation of the chemical, microstructural and functional properties is observed, whether in terms of the thermal, acoustic, hydric or mechanical behavior. During accelerated aging, variations of properties are observed: an increase of thermal conductivity, and water vapor sorption capacity for both binders and a decrease of acoustic performance for the lime-based binder. No variation of mechanical properties is observed. These results are linked to alterations of the chemical and microstructural properties: hydration and carbonation of the binder, mineralization, swelling and shrinkage and consumption of vegetal walls by micro-organisms. By comparing these results with measurements carried out under real conditions, this work shows that the performance of hemp concretes should remain stable for several years.

The main objectives of this article were to examine the feasibility of high quality laminate (carbon PEKK – Poly-Ether-Ketone-Ketone) manufacturing under low pressure and to analyze the principal phenomena governing the consolidation quality. The quality of laminate was evaluated in terms of the interlaminar shear strength measured by short-beam test and the residual voids observed by micrographic images. This work underlined the possibility to obtain a good interlaminar consolidation quality under a low pressure of 0.7 bar even for prepregs which were not designed for out-of-autoclave processes. To better understand the interlaminar consolidation phenomena, we developed an experimental set-up for the in-situ monitoring of the laminate consolidation to measure the change of laminate thickness and the temperature gradient in the thickness direction during the manufacturing process. Indeed the in-situ monitoring of temperature gradient through the laminate thickness is an effective way to observe the consolidation phenomena. In particular, we identified two major phenomena, the establishment of intimate contact between the adjacent layers at the glass transition temperature and the molten matrix flow at the melting temperature. The assumption on the intimate contact establishment at the glass transition temperature was confirmed by the heat transfer simulation considering the change of thermal contact resistance at the interlaminar interface.

International audience; The main objectives of this article were to examine the feasibility of high quality laminate (carbon PEKK-Poly-Ether-Ketone-Ketone) manufacturing under low pressure and to analyze the principal phenomena governing the consolidation quality. The quality of laminate was evaluated in terms of the interlaminar shear strength measured by short-beam shear test and the residual voids observed by micrographic images. This work underlined the possibility to obtain a good interlaminar consolidation quality, i.e., interlaminar shear strength of 100 MPa under a low pressure of 7.0 × 10 4 Pa even for prepregs which were not designed for out-of-autoclave processes. To better understand the interlaminar consolidation phenomena, we developed an experimental setup for the in-situ monitoring of the laminate consolidation to measure the change of laminate thickness and the temperature gradient in the thickness direction during the manufacturing process. In particular, we identified two major phenomena, the establishment of intimate contact between the adjacent layers at the glass transition temperature and the molten matrix flow at the melting temperature. The assumption on the intimate contact establishment at the glass transition temperature was confirmed by the heat transfer simulation considering the change of thermal contact resistance at the interlaminar interface.

Green routes to prepare or manufacture sustainable building materials have been attracting much attention over the years targeting sustainability issues. In this investigation, for the first time, sludge from the inert mineral part of the construction and demolition waste (RA-S) is used as a primary raw material in the fabrication of fired bricks for building purposes. Fired bricks fabricated with different dosages of RA-S and earth material (i.e., 0%, 30%, 50%, 70%, and 100% by weight) were prepared and evaluated in terms of their physical-chemical properties. The RA-S was characterized, and the results showed that it could be classified as a clayey material and richly graded silty sand according to the French Standards. XRD analysis revealed that the addition of the RA sludge into raw earth material provoked changes slightly in the fired bricks. The compressive strength (CS) results indicated that the CS of the fired bricks increased with the addition of the RA-S from 30% to 70%. The highest CS was attained at the firing temperature of 800 °C. The density of the fired brick slightly reduced with the RA-S addition. The thermal conductivity results suggest that RA-S has better insulation properties compared to earth material. The RA-S sludge can be used in combination with earth material to fabricate fired bricks, which can meet the requirements of many Standards all over the World. In the light of these results, it is possible to say that the RA-S generated from recycling inert mineral part of construction and demolition waste plant is an excellent raw material to prepare efficient fired bricks that can be successfully employed in the real construction sector. Also, the highlighted results suggest that brickwork factories have the opportunity to improve production quality while significantly reducing manufacturing time, energy consumption, resource depletion, and environmental impact. The authors are also grateful to the Council for the Development of Higher Education at Graduate Level, Brazil (CAPES) for the postdoctoral scholarship granted through the National Postdoctoral Program (PNPD). The authors also thank Mr. Ferro, president of Esterel Terassement, for financial support and for providing the RA-S samples. Dr. Simoes dos Reis gives a special thanks to the cooperation opportunity between UFRGS and IFSTTAR through his Post-doctoral studies provided by PNPD. E.C. Lima thanks to Foundation for Research Support of the State of Rio Grande do Sul (FAPERGS), and National Council for Scientific and Technological Development (CNPq, Brazil) for financial support and sponsorship.

Purpose The thermal modelling of an electrical machine is difficult because the thermal behavior depends on its geometry, the used materials and its manufacturing process. In the paper, such a thermal model is used during the sizing process by optimization of a hybrid electric vehicle (HEV). This paper aims to deal with the sensitivities of thermal parameters on temperatures inside the electrical machine to allow the assessment of the influence of thermal parameters that are hard to assess. Design/methodology/approach A sensitivity analysis by Sobol indices is used to assess the sensitivities of the thermal parameters on electrical machine temperatures. As the optimization process needs fast computations, a lumped parameter thermal network (LPTN) is proposed for the thermal modelling of the machine, because of its fastness. This is also useful for the Sobol method that needs too many calls to this thermal model. This model is also used in a global model of a hybrid vehicle. Findings The difficulty is the thermal modelling of the machine on the validity domain of the sizing problem. The Sobol indices allow to find where a modelling effort has to be carried out. Research limitations/implications The Sobol indices have a significant value according to the number of calls of the model and their type (first-order, total, etc.). Therefore, the quality of the thermal sensitivity analysis is a compromise between computation times and modelling accuracy. Practical implications Thermal modelling of an electrical machine in a sizing process by optimization. Originality/value The use of Sobol indices for the sensitivity analysis of the thermal parameters of an electrical machine.

Impregnation of European beech (Fagus sylvatica) with 10% w/w aqueous solution of different additives made from the reaction of glycerol or polyglycerol with glycidyl methacrylate or maleic anhydride followed by thermal modification at 150, 200 or 220 degrees C under inert conditions was investigated to evaluate potential synergies between chemical and thermal treatments. Treated and untreated wood were analysed to evaluate mass changes and bulking values after treatments, resistance of treatment to leaching, wettability, anti-swelling efficiency, modulus of elasticity (MOE), modulus of rupture (MOR), decay resistance against Coriolus versicolor and termite resistance against Reticulitermes flavipes. Results revealed that synergic effects between a combination of light chemical modification and thermal treatments can be observed at higher temperature treatments (200 and 220 degrees C), improving wood dimensional stability (approximately 80%), decay, and termite resistance properties. However, MOE and MOR values decreased by approximately 30% and 60%, respectively. Treated samples resulting from the combination of chemical and thermal treatment performed at 220 degrees C present improved durability against the termites R. flavipes.

Dans un contexte où il est indispensable d'apporter des réponses aux enjeux environnementaux majeurs auxquels notre planète est confrontée, un des principaux secteurs concernés est celui du bâtiment, pour lequel les logements sont encore en 2019 globalement mal isolés d'un point de vue thermique, mais également acoustique. Aussi, des solutions peuvent être apportées par des isolants biosourcés comme les laines végétales, capables de stocker le dioxyde de carbone atmosphérique, et possédant des propriétés multifonctionnelles à fort potentiel. Néanmoins, un certain nombre de verrous scientifiques freinent encore la croissance de ces matériaux sur le marché des isolants fibreux. Ils sont liés notamment à la méconnaissance des spécificités des laines végétales et au manque d'investigations concernant des approches de valorisation conjointe de leurs performances acoustiques et thermiques. Afin de répondre à ces problématiques, une démarche innovante est développée en s'appuyant sur une méthode d'Homogénéisation Auto-Cohérente conjointe acoustique et thermique, reposant sur une géométrie cylindrique (HAC cylindrique), en vue de l'optimisation des laines végétales du bâtiment. Ainsi, la conductivité thermique est déterminée en statique à partir du couplage d'un modèle « HAC cylindrique statique » pour le transfert par conduction et d'un modèle semi-empirique pour le transfert par rayonnement. L'absorption acoustique est quant à elle déterminée par un modèle « HAC cylindrique dynamique ». Cette méthode permet ainsi de lier les paramètres de leur microstructure, tels que la taille des fibres et la porosité, à leurs propriétés macroscopiques par l'établissement de relations analytiques. La validation de la procédure de modélisation conjointe ainsi développée s'effectue par comparaison des prédictions avec des résultats expérimentaux. Ces résultats sont issus de banques de données constituées à partir de campagnes de caractérisations de grandes ampleurs conduites au cours de la thèse sur plus de vingt matériaux différents. Elles concernent à la fois des paramètres liés à la microstructure spécifique des laines végétales, ainsi que leurs propriétés en absorption acoustique et en isolation thermique.

Real time thermal remote sensing of active volcanic systems is a crucial technique for understanding the behavior and eruptive activity of hot magmatic bodies. Such technology relies on determining the thermal emissivity of the magma, a parameter to identify the temperature of magma. We used a direct method to obtain a spectrum in the wavenumber range from 400 to 13000 cm-1; the natural (volcano Erebus and Teide) and synthetic samples were heated up from room temperature to 2000K with a CO2 laser and data were collected during all the heating stage with a FTIR spectrometer.Our results thus indicate that thermal emissivity of magmatic rock is affected by changes in composition and thermal history. The emissivity measurements show the important role of the iron and the cooling rate on the spectral response of the phonolite composition. These are important observations since different emissivity will lead to different temperature determinations and hence, an erroneous interpretation on the rheology and thermal efficiency of the magmatic body.; La télédétection thermique en temps réel de systèmes volcaniques actifs est une technique cruciale pour comprendre le comportement et l'activité éruptive de corps magmatiques chauds. Cette technologie repose sur la détermination de l'émissivité thermique du magma, un paramètre permettant d'identifier la température du magma. Nous avons utilisé une méthode directe pour obtenir des spectres dans la plage de nombres d’onde allant de 400 à 13000 cm-1; d’échantillons naturels volcaniques (volcan Erebus et Teide) et synthétiques (avec différents éléments). Ces matériaux ont été chauffés de la température ambiante à 2000K avec un laser CO2 et les données ont été collectées pendant toute la phase de chauffage avec un spectromètre IRTF.Nos résultats indiquent que l’émissivité d’une roche magmatique est affectée par les changements de composition et l’histoire thermique. Les mesures d'émittance montrent le rôle important du fer et de la vitesse de refroidissement du magma sur la réponse spectrale des compositions de type phonolitique. Ces observations sont importantes, car une méconnaissance des valeurs d’émissivité engendre des erreurs sur la détermination de la température et, donc à une interprétation erronée de la rhéologie et de l'efficacité thermique du corps magmatique.

This experimental study provides complete datasets of hygrothermal properties of numerous hemp-clay with density ranging from 200 to 350 kg m-3 for building thermal insulation. In addition, attention is also paid on protocols and methods, on the measurements repeatability and on the influence of conditioning temperature and relative humidity: mean uncertainties do not exceed 10% for all measurements, while initial conditioning influences at most the results, particularly for the sorption isotherm. Heat and moisture storage properties depend obviously of the constituent (hemp or clay). Furthermore, they can be estimated with a good accuracy with a mixing law. Thermal conductivity of the composites ranges between 0.06 and 0.12 W m-1 K-1 and clearly depends on the density. Water vapor diffusion resistance factor ranges between 2.24 and 4.14, while capillary absorption coefficient ranges between 0.027 and 0.135 kg m-2 s-0.5.

Functional properties of vegetal concretes, such as hygrothermal and acoustical properties, are brought by the microstructure of the vegetal particles. However, data are necessary to develop biobased insulation materials by providing results on their long-term behaviour, and only few studies focus on this topic. A first step is to characterise the behaviour of vegetal aggregates in bulk.In this study, hemp shiv is stored for two years in three different conditions: a static environment used as reference, accelerated aging conditions based on humidification and drying cycles, and an exterior aging. The potential evolution of functional properties of particles is monitored with time and depending on the aging conditions. These evolutions are understood thanks to a study at a microscopic scale, where the microstructure of the particles is investigated.This study shows that no variation is observed for the reference conditions, whereas four phenomena linked to aging can be identified for accelerated and exterior aging conditions: a mass loss, volume variations of the particles and an opening of the aggregates porosity for both storing conditions. The last one, only observed for exterior aging, is a modification of the pore size distributions. Keywords: Vegetal aggregate, Hemp shiv, Hygrothermal and acoustical properties, Microstructure, Microorganisms

In order to evaluate their potential to be used as charcoal production by a new industrial thermal treatment process; the wood of seven trees of introduced species in the North eastern Tunisia (3 Eucalyptus, 4 Casuarina) and 1 local species (Tetraclinis) were selected. Physical properties of natural woods and Gravimetric yields in charcoal, ultimate composition, heating values measurements and combustion quality tests were performed before and after carbonization process. For the same thermal degradation intensity (550 °C—4 h), Gravimetric yields in charcoal values were comprised between 41.1 and 45.3.9% for Casuarina wood species, 35.5 and 39.4% for Eucalyptus wood species and was 33.7% for Tetraclinis articulata wood. Elemental composition showed a significant difference between the selected species. It varies from 1.46 to 1.65 for H/C and 0.67 to 0.77 for O/C. Casuarina wood species showed the lowest values for the both ratios. The calorific values showed that the selected wood species have Heating Values ranged from 16.264to 20.798 MJ/kg and allow producing charcoal with heating values comprised between 23.871 and 30.943 MJ/kg. The best energetic improvement by carbonization process, in this work, concerns Eucalyptus and Tetraclinis woods, except for the Eucalyptus salmonophloia but the combustion quality showed that Casuarina wood species appears to be the wood species with the most optimal combustion, after undergoing a carbonization process.

New α(1 → 2) or α(1 → 3) branched dextrans with high molar masses and controlled architecture were synthesized using a dextransucrase and branching sucrases. Their molecular structure, solubility, conformation, film-forming ability, as well as their thermal and mechanical properties were determined. These new dextrans present structures with low densities from 9,500 to 14,000 g m−3 in H2O/DMSO medium, their molar mass, size and dispersity increase with increasing branching degree (weight-average molar mass up to 109 g mol−1 and radius of gyration around 500 nm). Dextrans exhibit a glass transition between 40.5 and 63.2 °C for water content varying from 12.2 to 14.1%. The effect of branching is mainly observed on the ability of dextran to crystallize. They have a good film-forming ability with a storage modulus which varies from 2 to 4 GPa within a relative humidity range of 10–50%.

An extensive characterization was carried out on various biomass samples representative of the diversity in France, including forestry samples (softwood and hardwood woodchips, eucalyptus and poplar short rotation coppices), very short rotation coppices (VSRC) samples and agricultural samples (wheat straw, triticale, fescue, miscanthus and switchgrass). The following properties were measured to evaluate suitability with thermochemical process: elemental analysis (C, H, O, N, S, and Cl), chemical composition (extractives, lignin, mono/polysaccharides, acetate groups), ash content and inorganic composition. Carbon and hydrogen contents are quite similar between biomasses. Agricultural biomasses are usually less oxygenated than forestry biomasses. Nitrogen content is generally higher for agricultural biomasses (up to 1.4 %) than for forestry biomasses, but important amount is also found in VSRC (0.8 % for poplar). Chlorine and sulfur are species-dependent. Fescue and eucalyptus show high values of Cl, while wheat straw has the highest sulfur content. Ash content is very low for forestry and perennial biomasses (miscanthus and switchgrass). For non-perennial crops, values up to 8.5 % (wheat straw) were measured. Agricultural biomasses contains more silicon (2 % for triticale), magnesium (0.16 % for fescue), potassium (1.9 % for fescue) and phosphorus (0.18 % for fescue), while forestry biomasses are richer in calcium (up to 0.97 % for poplar VSRC). Other inorganic elements, especially heavy metals are present in very low concentrations and most of the time below detection limits. Regarding chemical composition, extractive content is very high (20–25 %) for non-perennial crops (fescue, wheat straw and triticale) and eucalyptus VSRC. Lignin content seems to be higher for forestry biomasses (21–29 %) than for agricultural biomasses (16–23 %). The same trend was observed for cellulose, while the opposite was observed for hemicelluloses. These differences in organic and inorganic composition are expected to significantly impact the behavior of these biomasses in thermochemical processes such as gasification for biofuels production.

Oil palm shell is an interesting organic material that can be used as aggregate for concrete. It can help mitigate the environmental problems caused by the concrete industry. We intend to contribute to the knowledge of OPS (oil palm shells) concrete studying the physical mechanic and thermal behavior. Then, this paper presents the results of investigations carried out on the effects of replacing by volume, CGA (crushed granite aggregate) in concrete with OPS. Then, the dry density, apparent porosity, water absorption, electrical resistivity, thermal parameters, flexural strength, compressive strength and static elastic modulus are investigated. Microscopic analysis with an SEM (scanning electron microscopic) is also conducted. The results show that replacing crushed granite aggregate by OPS, increases the apparent porosity of concrete. This makes the concrete lighter and the concrete mechanical strengths lower. SEM analysis indicates that these decreases may be the consequence of a bad bond existing between the cement paste and OPS aggregate. Though, the compressive strength of OPS concrete which is 28 days old is acceptable for structural concrete. OPS concrete is more ductile and has a better thermal behavior compared to CGA concrete. (Resume d'auteur)

In this paper, the structure-property relationships of a clay ceramic with organic additives (biomass and biochar) are investigated to develop an alternative material for thermal energy storage. The firing transformations were elucidated using X-ray pair distribution function analysis, differential scanning calorimetry and scanning electron microscopy. It was found that the biomass transformed into porosity, which resulted in a decrease of the specific heat capacity. On the other hand, the biochar remained in the clay ceramic without any interaction with the clay matrix up to 950°C. The specific heat capacity of the clay ceramic increased from 1.20 kJ/kg.K to 1.49 kJ/kg.K for a 30 wt.% addition of biochar. The clay ceramic with a 30 wt.% addition of biochar also conserved a high flexural strength of 11.1 MPa compared to that of the clay ceramic without organic additives (i.e., 18.9 MPa). Furthermore, the flexural strength only decreased by 23% after 100 thermal cycles. The crack growth associated with the thermal fatigue was limited by crack bridging and crack trapping. The current results suggest that clay/biochar ceramics can be as efficient as molten salts in thermal energy storage with the added benefit of an ease of use in the physical form of bricks. This article is protected by copyright. All rights reserved.

The aim of this study was to determine and compare the melting (T-m), glass transition (T-g) and mechanical relaxation (T-alpha) temperatures of a new waxy cassava starch. Thermal transitions measurements were obtained by Differential Scanning Calorimetry (DSC) and Dynamical Mechanical Thermal Analysis (DMTA). The experimental data showed a high correlation between water volume fraction and melting temperature (T-m) indicating that the Flory-Huggins theory can be used to describe the thermal behavior of this starch. The T-m of waxy cassava starch-water mixes were lower than a waxy corn starch-water reference system, but differences were not statistically significant. The mechanical relaxation temperatures taken at tan delta peaks were found 29-38 degrees C larger than T-g. The T-alpha and T-g measured for waxy cassava starch exhibited similar properties to the ones of waxy corn starch, implying that waxy cassava starch can be used in food and materials industry.

Novel fibers containing different ratios of PVA and d-limonene were fabricated using electrospinning for antibacterial active packaging applications. The PVA/d-limonene fibers were thoroughly characterized using a scanning electron microscope, fourier-transform infrared spectrometry, thermal gravimetry, differential scanning calorimetry, tensile tests, and oxygen permeability tests. The results of these analyses showed that the highest tensile strength and elongation at break values of 3.87 &plusmn, 0.25 MPa and 55.62 &plusmn, 2.93%, respectively, were achieved for a PVA/d-limonene ratio of 7:3 (v/v) and an ultrasonication time of 15 min during processing. This material also showed the lowest oxygen permeation and the best degradability and bacteriostatic properties of all samples.

Delayed ettringite formation in concrete is likely to lead to swelling and cracking in structures which have undergone eartly age heating to a temperature of over 65°c. Application of a method that accelerates this process has made it possible to study the impact of cement properties on DEF.

The heating value is one of the most important properties of animal fats, vegetable oils and biodiesels for their use as fuels in stead of petroleum. There are lots of formulae or correlations encountered in the literature to evaluate biomass fuels’ higher heating value (HHV). Lots of them are not specially established for vegetable oils, animal fats and their derivatives. In this paper, some correlations previously published and based on ultimate analysis or fatty acid composition are applied to some bio oils samples collected from the literature. The aim of this article is to investigate what of them can be used to estimate animal fats, biodiesels, vegetable oils and their derivatives HHV with a high accuracy. With an absolute average error inferior to 4%, the results show that the formulae of : Channiwala and Parikh, Boie and Vondracek, Boie, Vondracek, Fassinou et al. Milne, IGT, Demirbas and Dulong can be used at this purpose with a high accuracy by comparison to the bomb calorimetric method.

The power electronics components (and still will have!) have a great influence on the energy and transport sectors. These parts are made of ceramic-copper assemblies for which the mechanical strength must be controlled to ensure durability about 30 years under the thermal cycles increasingly larger. A failure mechanisms analysis in DBC (Direct Copper Bonding) assemblies used in power electronics is studied (the delamination along the interface copper - ceramic and/or the brittle ceramic fracture). To identify the elastoplastic behavior of copper, we showed that it’s necessary to use a copper plate having undergone the heat hole treatments related to the assembly process. The ceramic gragile elastic behavior is descrobed within the Weibull statictics framework. Consequently, a copper-ceramic delamination characterization under four points bending made it possible to identify a cohesive model for the interface. The cohesive calibration parameters is carried out by using the data in two scales: i) strentgh-displacement macroscopic ii) local cracking optical follow-up with imposed displacement. The mechanical integrity of DBC assemblies of different thickness of copper and ceramic has been studied. We showed that the configurations with a ratio close to the unit are most dangerous by generating a delamination, which continues under thermal cycling. This risk of delamination can be notably reduced by structuring the copper circumference surface with cylindrical holes distributed periodically. Thus, a finite elements model allowing us to evaluate the most promising assemblies in term of durability, was estabilshed. In the absence of geometrical defects, the copper layer must remains, even in the delamination case whose face induces a concentration stress., Les composants d’électronique de puissance ont (et vont encore avoir !) eu une grande influence sur les secteurs de l'énergie et des transports. Ces pièces sont notamment constitués d’assemblages céramique –cuivre pour lesquels la tenue mécanique doit être maîtrisée afin de garantir dans le future une durabilité d’environ 30 ans sous l’action de cycles thermiques plus en plus grande. Une analyse des mécanismes de défaillance des assemblages DBC (Direct Bonding Copper) utilisés en électronique de puissance est étudiée (le délaminage le long de l’interface cuivre -céramique et/ou la rupture fragile de la céramique). Pour identifier le comportement élastoplastique du cuivre, nous avons montré qu’il est nécessaire d’utiliser une plaque de cuivre ayant subi l’ensemble des traitements thermiques liés au processus d’assemblage. Le comportement élastique fragile de la céramique est décrite dans le cadre d’une statistique de Weibull. Dès lors, une caractérisation du délaminage cuivre-céramique sous flexion quatre points a permis d’identifier un modèle cohésif pour l’interface. La calibration des paramètres cohésifs est menée en utilisant les données à deux échelles : i) macroscopique de force-déplacement ii) locale de suivi optique de la fissuration avec le déplacement imposé. L’intégrité mécanique des assemblages DBC pour différentes épaisseurs des couches de cuivre et de céramique a été étudié. Nous avons montré que les configurations avec un rapport proche de l’unité sont les plus dangereuses en engendrant un délaminage, qui se poursuit sous cyclage thermique. Ce dernier peut être notablement réduit en structurant le pourtour de la surface de cuivre avec des trous cylindriques répartis périodiquement. Ainsi, un modèle éléments finis permettant d’évaluer les assemblages les plus prometteurs en terme de durabilité a été établie. En l’absence de défauts géométrique, la couche de cuivre reste intègre, même dans le cas d’un délaminage dont le front induit une concentration de contrainte.

Two techniques to characterize the thermal properties of materials and to analyze the heat transfer at the micro/nanoscales have been studied and are presented in this manuscript. The first technique is an Atomic Force Microscopy (AFM)-based Scanning Thermal Microscopy (SThM) technique. Operating in its active mode, the AFM probe integrates a resistive element that is electrically heated. Used in AFM contact mode, it allows the localized thermal excitation of the material to be studied. The determination of the sample thermal properties requires the analysis of the probe thermal response through the modeling of the probe-sample system including its surrounding. Through a state of the art of the SThM studies, the current scientific questions and the analytical models used to analyze the probe-sample system are exposed. Special attention is given to the probe-sample thermal interaction that conditions the tip-sample interface temperature. In this work, a new methodology based on the analysis of the dependence of force-distance curves on probe temperature obtained in ambient air has been established. It permits the study and the specification of the heat rate exchanged between probe and sample through thermal conduction through water meniscus. The methodology has been applied with samples with different thermal properties, surface roughness and wettability to three resistive probes different in size and heater configurations: Wollaston, KNT and doped silicon (DS) probes. Whatever the probe and the sample are, the contribution of water meniscus in the probe-sample interaction has been shown to be lower than the one through air. The thermal conductances at the solid-solid contact were determined for various samples. This allowed identifying the phonon transmission coefficient in the case of KNT probe and a nonmetallic sample. The heat conduction through air strongly depends on the sample thermal conductivity. Moreover, the sensitivity to sample thermal conductivity for the Wollaston and KNT probes is shown to be strongly reduced for thermal conductivities larger than 10 and few W.m-1.K-1 respectively. The second technique developed in this thesis is a less local thermal analysis method. It operates by contact, requiring the implementation of the sample with a network of resistive wire probes. One wire of the network is heated by an alternating current at frequency f and has the role of heating source, continuous and at 2f frequency, for the sample. A 2D analytical model, based on the principle of thermal-waves, was developed to identify though the measurements the effective thermal properties of anisotropic samples. Finite element simulations and this model were used to design the experimental set-up and validate the method on a sample of pure silicon. The results obtained at sample temperatures ranging from ambient to 500 K are consistent with literature., Deux techniques de caractérisation thermique des matériaux et d’analyse du transfert de chaleur aux micro- et nano- échelles ont été étudiées et sont présentées dans ce mémoire. La première technique est la microscopie thermique à sonde locale (SThM). La pointe d’un microscope à force atomique intègre un élément résistif. Utilisée en mode contact, cette pointe, chauffée par effet joule, permet l'excitation thermique localisée de l’échantillon. La détermination des propriétés thermiques de l’échantillon nécessite l'analyse de la réponse de cette pointe avec un modèle du système sonde-échantillon et de son environnement. Un état de l'art général des études réalisées en SThM permet de poser les questions scientifiques actuellement traitées dans le domaine. Une attention particulière est accordée à l'interaction thermique sonde-échantillon. L’étude ici présentée tient compte des propriétés thermiques, de la rugosité et de la mouillabilité de la surface de différents échantillons. Une nouvelle méthodologie est établie pour la spécification du transfert de chaleur échangée par conduction thermique au travers du ménisque de l'eau formé au contact sonde-échantillon. Cette méthodologie est basée sur l'analyse de la dépendance à la température de la sonde des courbes de force-distance obtenues à l'air ambiant. Elle est appliquée à trois sondes de taille, forme et constitution différentes: la sonde Wollaston, la sonde KNT et une sonde en silicium dopé. Quels que soient la sonde et l'échantillon, la contribution du ménisque d’eau à l'interaction est montrée être inférieure à celle de l'air. La conductance thermique au contact solide-solide est déterminée pour différents échantillons. Cela a permis d’identifier le coefficient de transmission de phonons dans le cas de la sonde KNT et des échantillons non-métalliques. La conduction thermique via l’air dépend fortement de la conductivité thermique de l'échantillon. La sensibilité à la conductivité thermique pour les sondes Wollaston et KNT est part ailleurs montrée fortement réduite pour les matériaux de conductivité thermique supérieure à 10 et quelques W.m-1.K-1 respectivement. La seconde technique développée est une méthode d’analyse thermique moins locale nécessitant l’instrumentation de la surface de l’échantillon avec un réseau de sondes résistives filiformes. L’un des fils du réseau, chauffé par un courant alternatif à la fréquence f, a le rôle de source excitatrice continue et à la fréquence 2f de l’échantillon. Un modèle analytique 2D, basé sur le principe des ondes thermiques et développé pour identifier les propriétés thermiques d’échantillons anisotropes est présenté. Des simulations par éléments finis et avec ce modèle ont été utilisées pour dimensionner le montage expérimental et valider la méthode sur un échantillon de silicium pur. Les résultats obtenus à des températures de l’échantillon variant de l’ambiante à 500 K corroborent ceux de la littérature.

Perfil laminado de madera encolada para carpinterfa interior y exterior, que comprende una pluralidad de laminas (2) de pino negro, encoladas mediante adhesivo bicomponente (3) formado por una emulsion polimérica de isocianato y endurecedor libre de formaldehido. Procedimiento de fabricacion de un perfil laminado de madera encolada de pino negro.

Coupling of time-resolved synchrotron X-ray diffraction at both small and wide angles with differential scanning calorimetry is a new technique that allows simultaneous characterization of thermal and structural properties of a sample. The apparatus, called Microcalix, works between –30 and +230C at scanning rates comprised between 0.01 and 20C min–1 with a high sensitivity in both measurements using a single sample of small volume (from about 1 to 20 μL). The last version of the instrument is designed for laboratory bench and conventional source but preferably with rotating anode or multilayered mirrors. Measurements under low pressure or under shear as well as recordings of isothermal evolution are also possible. The example of the study of polymorphism of a monounsaturated triglyceride (PPO) will be presented as an application.

PLoS OneISI Document Delivery No.: AD7QOTimes Cited: 0Cited Reference Count: 68Nordey, Thibault Lechaudel, Mathieu Saudreau, Marc Joas, Jacques Genard, MichelCiradThe CIRAD (http://www.cirad.fr/) has supported this work. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Public library scienceSan francisco; International audience; Fruit physiology is strongly affected by both fruit temperature and water losses through transpiration. Fruit temperature and its transpiration vary with environmental factors and fruit characteristics. In line with previous studies, measurements of physical and thermal fruit properties were found to significantly vary between fruit tissues and maturity stages. To study the impact of these variations on fruit temperature and transpiration, a modelling approach was used. A physical model was developed to predict the spatial and temporal variations of fruit temperature and transpiration according to the spatial and temporal variations of environmental factors and thermal and physical fruit properties. Model predictions compared well to temperature measurements on mango fruits, making it possible to accurately simulate the daily temperature variations of the sunny and shaded sides of fruits. Model simulations indicated that fruit development induced an increase in both the temperature gradient within the fruit and fruit water losses, mainly due to fruit expansion. However, the evolution of fruit characteristics has only a very slight impact on the average temperature and the transpiration per surface unit. The importance of temperature and transpiration gradients highlighted in this study made it necessary to take spatial and temporal variations of environmental factors and fruit characteristics into account to model fruit physiology. (Résumé d'auteur)

O objetivo do presente trabalho foi determinar a composição química elementar e a estimativa do poder calorífico inferior da madeira em diferentes clones de Eucalyptus. Foram avaliadas duas árvores de 15 clones, plantados em teste clonal na empresa Votorantim Bioenergia, localizada em Vazante-MG. Os resultados indicaram que os clones 280/75, 16/JC e 299/75 apresentam maior potencial para utilização como fonte de energia. Destes destacaram-se os clones 16/JC e 299/75, por terem apresentado maior teor de hidrogênio, menor teor de nitrogênio, baixa relação C/N e elevada estimativa do poder calorífico inferior (PCi). Já os clones 38/JC (47,21%) e o 62/JC (47,35%) foram os que apresentaram os menores teores de carbono e as menores estimativas de PCi.

Colloque avec actes et comité de lecture. Internationale.; International audience; Les températures de fabrication des enrobés bitumineux ont une importance capitale pour garantir un bon collage bitume-granulat. Cependant l'évaluation précise de la qualité de collage reste un vrai challenge. Cette étude présente une méthode thermique d'évaluation de la qualité du collage à par la mesure de la résistance de contact à l'interface bitume-granulat. Grâce à un appareil original de mesure, et par résolution numérique du problème de conduction dans le bitume et granulat, on détermine la résistance thermique de contact qui est interprétée comme indicateur de la qualité du collage.

EPF 2010 - 10th European Power Electronics Conference, St Nazaire, FRANCE, 30-/06/2010 - 02/07/2010; Cet article présente des travaux de caractérisations thermiques statiques d'un ensemble d'interfaces thermiques. Ces dernières sont utilisées pour la gestion thermique en électronique de puissance. Ces caractérisations sont basées sur la norme ASTM D5470. L'objectif est d'extraire la conductivité thermique pour caractériser le vieillissement des interfaces. Des caractérisations transitoires complémentaires seront présentées en perspectives afin de voir si une analyse transitoire pourrait permettre de caractériser leur vieillissement à travers la capacité thermique volumique.

International audience; Tannin-based rigid foams were shown to be good thermal insulating materials for use in the cavity of hollow-core wooden doors and other wooden cavities. Their thermal insulation capacity is com- parable to that of totally synthetic, oil-derived foams, such as polyurethanes, but with the advantage that they do not burn and thus do not emit toxic gases on burning. Exposure to the weather of wooden hollow core structures fi lled with tannin-based foams confi rm that the wood in contact with the foam is not affected by the acidity of the foam due to the already previously demonstrated incorporation of the acid hardener used by coreaction with the hardened polymer network.

Pour des échantillons de chêne vert de la région d'Azrou au Maroc, nous avons effectué des expérimentations pour la détermination de la conductivité thermique [lambda] et de certaines propriétés mécaniques. Les modules élastiques {ER , ET, EL, G TL, G RL, G RT} et les paramètres {( STL)-1 , ( SLR)-1, ( SRT)-1} sont déterminés au LMGC à l'aide d'une technique de goniométrie ultrasonore et sont ensuite comparés à ceux calculés en utilisant le modèle de GUITARD. La conductivité thermique [lambda] est mesurée au CIRAD-Forêt sur des éprouvettes débitées sur dosse et sur quartier par le biais de la méthode dite du ruban chaud.

Boom clay, a stiff clay from the Underground Research Laboratory (URL) at Mol (Belgium) may be the host medium for a long-term radioactive waste storage facility. To study the thermal-hydromechanical properties of this clay, an experimental investigation was carried out on a testing system permitting high pressure triaxial tests at controlled temperature. Thermal and mechanical consolidation tests were carried out, following isobar heating and isothermal compression paths. The results showed that a compression and heating velocity lower than that in the literature seemed necessary to ameliorate the consolidation of the soil samples. Creep behaviour was observed at an isobar and isothermal state following an isotropic compression or a heating. Heating tests showed a clear effect of temperature on the creep behaviour of the soil.

Diplôme : Docteur de l'ENSAR

An experimental study has been carried out to determine thermophysical properties of tropical wood. Five species, covering a wide range of densities of most of the wood used in Central Africa, has been chosen. These properties which characterise the thermally insulating materials, are related to basal density in order to help predict the thermophysical properties of any tropical wood as soon as its basal density is known. Steady-state and unsteady state methods were used to measure thermal conductivity and thermal diffusivity, respectively. Specific heat and thermal effusivity were then calculated. The influences of moisture content and the principal cutting plan on the thermophysical properties of tropical wood were examined. Higher conductivity, diffusivity and effusivity in the axial direction were observed, as well as the non-directional dependence character of the specific heat. It was also observed that thermal conductivity of tropical wood increases with infradensity both in the axial and the transverse directions. Finally, it was shown that conductivity and effusivity increase and thermal diffusivity decreases with the increase of moisture content. © 2005 Elsevier Ltd. All rights reserved.

International audience; Most of the heat dissipation occurs when water evaporates. After heap turning, around one half of the heat production is stored in the heap until the maximum temperature is reached. Then, the sensible heat represents around another half of the heat production.Heat is produced during composting process by aerobic degradation of solid cattle manure. Our target was to quantify the kinetic of heat partition between the heap itself, and losses in the air as water vapour or sensible heat. One ton of cattle manure was disposed during six weeks in two small cells with controlled air temperature. One heap has been turned over twice and the other not. We measured the sensible heat, water vapour and carbon dioxide lost by each cell, and the temperature distribution in each heap. Most of the heat dissipation occurs when water evaporates. After heap turning, around one half of the heat production is stored in the heap until the maximum temperature is reached. Then, the sensible heat represents around another half of the heat production, and the heat storage becomes negligible. Our results suggest that extensive heat retrieval is possible on the farm with water pipes disposed near the top or the bottom of the heap. More intensive heat retrieval should include the condensation of the water vapour emitted. (Résumé d'auteur)

The thermal behavior of fabrics depends on many morphological and structural parameters. In this paper, an experimental device for measuring heat absorption of textile materials in transient state, is developed. The heat absorbed in transient state by a fabric is connected to the warm or cool feeling during the handle. When the human skin touches a garment which is at a different temperature, heat exchange occurs between the two bodies and the warm or cold feeling is the very first sensation. The experiment simulates this transfer of energy. Moreover, the influence of some tribological aspects, on fabric thermal behavior is analyzed. The cotton variety, the yarn structure (single or plied yarn) and the stitch length of the knitted fabrics used are the parameters of the study. The results bring into light that transient thermal properties and surface state characteristics are influenced by parameters on three scales: fiber (microscopic scale), yarn (mesoscopic scale) and fabric (macroscopic scale), whose importance will be discussed.

The effects of tillage on the energy balance and temperature of bare soil were studied using three plots that had different soil structures due to different times of seedbed preparation and soil compaction. The experiment was performed on a loamy soil (Gleyic luvisol) in northern France during the establishment of sugar beet in spring 1992. Temperature, water content, heat capacity and thermal conductivity of the ploughed layer, surface albedo and roughness, net radiation, soil heat flux, sensible heat flux and evaporation were all measured over a spring-tilled soil, an autumn-tilled soil and a compacted soil. Differences in soil heat fluxes were related to soil evaporation and thermal conductivity. Differences in soil temperatures were related to heat capacity. In spite of a considerable evaporation, the compacted soil had the highest soil heat flux because of its high thermal conductivity. Nevertheless, the spring-tilled soil was the warmest because of its low heat capacity, and sugar beet germinated more rapidly with spring soil tillage. (© Inra/Elsevier, Paris.), Une expérimentation a été conduite dans un sol limoneux (Gleyic luvisol) dans le Nord de la France pendant la phase d’implantation d’une culture de betterave sucrière au printemps 1992 pour étudier les effets du travail du sol sur le bilan d’énergie et sur le régime thermique du sol. La température, l’humidité, la capacité calorifique, la conductivité thermique au sein de la couche labourée, l’albédo et la rugosité de la surface, le rayonnement net, le flux de chaleur dans le sol et dans l’air et le flux de chaleur latente ont été mesurés dans un sol travaillé au printemps, dans un sol travaillé à l’automne ou dans un sol fortement compacté. Les différences de flux de chaleur dans le sol entre traitements étaient liées aux niveaux d’évaporation et à la conductivité thermique ; les différences de température étaient liées à la capacité calorifique. Le sol fortement compacté avait le flux de chaleur le plus élevé malgré un niveau d’évaporation important, à cause de sa forte conductivité thermique. Mais c’était le sol travaillé au printemps qui était le plus chaud à cause de sa faible capacité calorifique, entraînant une germination des betteraves sucrières plus rapide. (© Inra/Elsevier, Paris.)

L'article précise la relation bois énergie/eau à deux niveaux : Définir l'influence de l'eau sur des rendements de transformation énergétique, préciser le rôle de l'eau du bois sur la qualité et les propriétés des bois transformés

Ce travail concerne la compréhension des mécanismes de transformation hydrothermique de l'amidon et plus généralement la maîtrise des transformations thermiques de l'amidon intervenant dans la fabrication d'amidons modifiés particulaires, utilisés comme agents texturants. Il met en évidence une variabilité structurale et fonctionnelle de différents amidons. L'analyse des modifications structurales de l'amidon, induites par un traitement thermique conventionnel à l'échelle du laboratoire, a conduit à une meilleure connaissance du degré de transformation de l'amidon dans le diagramme teneur en eau-température-temps et à une identification plus précise des transitions de phase de l'amidon de manioc. Les deux transitions thermiques observées ont été attribuées à des processus de dissolution de l'amidon survenant dans des conditions de teneur en eau différentes. L'étude de l'effet d'un traitement micro-ondes a permis de déterminer les conditions nécessaires pour transformer un amidon à l'échelle pilote

Les économies des pays tropicaux sont encore basées sur l'agroindustrie et les industries du bois. Ces industries générent une quantité importante de déchets néfastes à l'environnement. L'utilisation rationnelle de ces résidus à travers les technologies de l'énergie de la biomasse serait une solution appropriée. Le but de ce travail consiste à mettre en place une méthodologie adaptée aux économies des pays tropicaux. Le premier chapitre présente la structure économique des pays de l'ASEAN. Le deuxième chapitre présente les différentes possibilités de conversion thermochimiques

Not available, L'état thermique d'un supraconducteur unidimensionnel est géré par une équation parabolique semi-linéaire ; le terme source représente ici la compétition entre la puissance volumique dissipée dans le conducteur par effet joule et celle qui est absorbée par le bain cryogénique de température Tb dont le rôle est de maintenir l'installation en dessous de sa température critique Tc. Après une perturbation thermique accidentelle (pendant laquelle seules les extrémités du conducteur peuvent être strictement contrôlées par le bain), la température du conducteur évolue de façon transitoire vers l'une des trois solutions stationnaires éventuellement possibles, parmi lesquelles T = Tb est la seule souhaitable. Ce mémoire propose: un certain nombre de critères suffisants, portant sur des paramètres physiques de l'installation, pour que T = Tb soit la seule solution stationnaire possible du problème ; une explicitation numérique d'un critère optimal (parce que nécessaire et suffisant) proposé dans une thèse antérieure mais peu exploitable sous sa forme théorique ; un calcul numérique des deux solutions stationnaires autres que Tb ; lorsque aucun des critères proposés ne peut être satisfait ; quelques informations sur l'évolution de la température après une perturbation thermique ; plusieurs généralisations de l'étude: situation tridimensionnelle, coefficient dépendant de la température, forme du terme source