Numerical simulations of thermal processes are based on known geometry, material properties, initial and boundaries conditions. The massive use of these simulations in the metallurgical industry (for example for simulation of heat treatment of steel) is limited by the knowledge of precise boundary conditions, which are not easy to determine in compare to other input parameters. Empirical formulas are not sufficiently accurate for most non-trivial processes. Therefore, it is necessary to obtain the boundary conditions by experimental way. Boundary conditions can not be measured directly. The boundary conditions are determined by solving inverse heat conduction problem based on the measured temperature records. This doctoral thesis focuses on two types of the inverse heat conduction problems, which are poorly solved by existing methods. The first type are tasks that contains sharp increase/decrease in the values of the boundary conditions. Two new approaches are proposed and compared in this thesis for this type of tasks. The second type are tasks with non-stationary and non-homogeneous cooling. Three new methods were developed for this case. They are applied for the case of water cooling of vertical aluminum sample. The base characteristics of the current task is inhomogeneous cooling. One part of the surface is cooled intensively by flowing water in contrast to the other part of surface which is cooled only with low intensity since it is protected from direct contact with water by the vapor layer (Leidenfrost effect). The positions of these two part of surface are not stationary (they change during the experiment). The newly developed methods are compared to each other.

Le domaine de la science des matériaux et plus particulièrement celui des matériaux hybrides suscite un intérêt croissant en raison de leurs nombreuses applications. Dans ce travail, deux stratégies synthétiques ont été considérées pour la synthèse de matériaux hybrides.Dans une première partie, nous nous sommes intéressés à une approche de synthèse directe en faisant réagir des ligands organiques de type oligophénylène avec de l’isopropoxyde de titane. Malheureusement, ces réactions ont conduit à la précipitation de solides amorphes ne permettant pas la caractérisation de ces produits.Dans une seconde partie, une approche de synthèse séquentielle qui consiste à synthétiser un objet précondensé pouvant s’auto-Assembler dans un second temps avec des ligands organiques a été proposée. Cette approche nous a conduits à synthétiser une nouvelle brique de formule Ti10O12(cat)8(pyr)8 et de trois dérivés de formules analogues Ti10O12(cat)8(pyr’)8 (pyr’ = pyridines substituées) obtenus par échange de ligands. Ces complexes, qui présentent des propriétés d’absorption dans le visible, ont été étudiés par spectroscopie d’absorption UV-Vis et grâce à des calculs théoriques. Puis nous avons utilisé le motif [Ti10O12(cat)8] pour générer des matériaux hybrides via des substitutions de ligands par des molécules polytopiques comme la 4,4’-Bipyridine et la poly(4-Vinylpyridine). / In the field of materials science, hybrid materials are of crucial importance due to their numerous applications. In this work, two strategies were considered to synthesize such hybrid materials.In a first part, we have tackled a one step synthetic approach by reacting resorcinol-Based oligophenylene organic ligands with titanium isopropoxide. Unfortunately, these reactions led to amorphous solids and no further structural information concerning these precipitates was obtained.In a second part, we have described a sequential approach which first concerns the preparation of pre-Ordered systems that are, in a second step, self-Assembled with organic linkers. Thus, our approach deals with the preparation of a new building block formulated as Ti10O12(cat)8(pyr)8 and three derivatives formulated as Ti10O12(cat)8(pyr’)8 (pyr’ = substituted pyridine) obtained by ligands exchange. These complexes exhibit visible light absorption properties that were studied through UV-Vis absorption spectroscopy and theoretical calculations. Then, the [Ti10O12(cat)8] motif was used to generate hybrid materials via ligands substitutions with polytopic ligands such as 4,4’-Bipyridine and poly(4-Vinylpyridine).