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De nos jours, le domaine de la thermoplasmonique subit un développement très rapide. Ce domaine est basé sur l’amplification de la lumière absorbée par la nanoparticule métallique qui la transforme en une nanosource thermique optiquement activée. Un des défis qu’il faudra relever en thermoplasmonique est la manipulation et la valorisation de l’énergie thermique à petite échelle. De nouvelles techniques optiques permettent d’étudier les phénomènes thermiques liés aux nanoparticules plasmoniques. Ces techniques permettent de caractériser la distribution de température autour de nanoparticules métalliques avec néanmoins une résolution spatiale limitée par la diffraction. Dans cette thèse, nous présentons une nouvelle approche d’imagerie moléculaire, basée sur la nanopolymérisation amorcée thermiquement, pour caractériser le profil de chaleur au voisinage d’une nanoparticule métallique unique photo-excitée. Cette approche repose sur une formulation thermo-polymérisable caractérisée par une température seuil Ts qui est la température à partir de laquelle aura lieu la réaction de polymérisation. Nous développons ainsi des formulations présentant des Ts différentes. Après l’irradiation de la nanoparticule couverte par la solution thermo-polymérisable, la coquille de polymère créée est l’empreinte des zones où la photoconversion a induit une température supérieure à Ts. Nous démontrons la capacité de cette méthode à cartographier le champ thermique induit autour de la nanoparticule avec une résolution de l’ordre de dizaine de nanomètres (mieux que 35 nm) / Nowadays, the thermoplasmonic field undergoes a very interesting applications development thanks to the amplification of the light absorbed by the metal nanoparticle, which makes it an ideal nanosource of heat controlled by light. Because of this applications development, one of the challenges is to control and manipulate the thermal energy on a small scale.New optical techniques are dedicated to studying the thermal phenomenon induced by plasmonic nanoparticles. These techniques show different capacities to quantify and characterize the heat generated and the temperature distribution around nanoparticles. But the spatial resolution achieved is still limited by diffraction.In this thesis, we present a new molecular imaging approach, which is based on the nanopolymerization reaction thermally induced to characterize the heat profile in the vicinity of a single photoexcited nanoparticle. This approach is based on a thermo-polymerizable formulation with specific temperature threshold Tth (the temperature required to induce polymerization reaction). We develop formulations with different Tth. After irradiation of the nanoparticle covered by the thermo-polymerizable solution, the polymer shell created is the impression of areas where the photoconversion induced a temperature higher than Tth. We demonstrate the ability of this method to map the thermal field induced around the nanoparticle with a resolution better than 35 nm

This thesis focuses on fire resistance of 19th century cast iron framed structures. Based on material property data obtained from a comprehensive literature review, upper and lower bound relationships of the thermal and mechanical properties of 19th century fireproof floor construction materials have been derived. Because these materials have large variability, a sensitivity analysis has been undertaken to investigate the most effective ways of representing such variability. The sensitivity analysis has indicated that the elevated mechanical properties of cast iron should be reliably quantified. The thermal expansion of cast iron can be taken as equal to that of steel as in EN1993-1-2. Variabilities in other material properties have modest effects on fire resistance of cast iron structures and can be safely modeled according the Eurocode material models for similar modern materials (using thermal properties of modern steel for cast iron, using thermal properties of modern concrete for the insulation materials of cast iron structures). In order to resolve some of the uncertainties in mechanical properties of cast iron at elevated temperatures, a total of 135 elevated temperature tests have been performed, including tension and compression tests, transient state and steady state tests, tests after cooling down and thermal expansion tests. These test results have been used to establish the elevated temperature stress-strain-temperature relationships in tension and compression. Afterwards, calculation methods are developed to calculate the bending resistance of cast iron beams and compression resistance of cast iron columns at elevated temperatures. For cast iron beams, a fibre model has been developed to calculate elevated temperature moment capacity of cast iron beams in jack arch construction, taking into consideration non-uniform temperature distributions in the cross-section. The fibre model divides the cross section into a large number of fine layers and for a given curvature and neutral axis position calculates the strain, the temperature, the stress and the force of each layer. It has been found that under historically applied load, the fire resistance of such beams can be 60 minutes or higher. The Monte Carlo simulation method has been used to take into account the variabilities of important mechanical properties of cast iron at elevated temperatures; Young’s modulus, 0.2% proof stress, ultimate strength, corresponding strain at ultimate strength and failure strain in tension and Young’s modulus, proportional limit and 0.2% proof stress in compression. This has enabled material safety factors of 1.50, 2.50, 4.50 and 5.50 to be proposed for target failure probabilities of 10-1, 10-2, 10-3 and 10-4 respectively. For cast iron columns, a finite element model, built using the commercial software ABAQUS, has been used to examine the effects of changing different design parameters (column slenderness, member imperfection, cross section imperfection, degree of axial restraint, load factor and load eccentricity) on fire resistance of cast iron columns. Validation of the finite element model was by comparison of the simulation results against six fire resistance tests, three on unprotected and three on protected cast iron columns. The results of this numerical parametric study indicate that the fire resistance of cast iron columns is generally higher than that of modern steel columns because the applied loads on cast iron columns are lower and cast iron columns have thicker sections than modern steel columns. Comparison of the numerical parametric study results with the calculation results using the steel column design method in EN1993-1-2 has found that the EN 1993-1-2 calculation results are generally on the safe side.

Junctions are the key component for 3D carbon nanotube (CNT)-graphene seamless hybrid nanostructures. Growth mechanism of junctions of vertical CNTs growing from graphene in the presence of iron catalysts was simulated via quantum mechanical molecular dynamics (QM/MD) methods. CNTs growth from graphene with iron catalysts is based on a ‘‘base-growth’’ mechanism, and the junctions were the mixture of C-C and Fe-C covalent bonds. Pure C-C bonded junctions could be obtained by moving the catalyst during CNT growth or etching and annealing after growth. The growth process of 3D CNT-graphene junctions on copper templates with nanoholes was simulated with molecular dynamic (MD) simulation. There are two mechanisms of junction formation: (i) CNT growth over the holes that are smaller than 3 nm, and (ii) CNT growth inside the holes that are larger than 3 nm. The growth process of multi-layer filleted CNT-graphene junctions on the Al2O3 template was also simulated with MD simulation. A simple analytical model is developed to explain that the fillet takes the particular angle (135°). MD calculations show that 135° filleted junction has the largest fracture strength and thermal conductivity at room temperature compared to junctions with 90°,120°, 150°, and 180° fillets. The tensile strengths of the as-grown C–C junctions, as well as the junctions embedded with metal nanoparticles (catalysts), were determined by a QM/MD method. Metal catalysts remaining in the junctions significantly reduce the fracture strength and fracture energy. Moreover, the thermal conductivities of the junctions were also calculated by MD method. Metal catalysts remaining in the junctions considerably lower the thermal conductivity of the 3D junctions.

Thermal and flash photolysis studies of ligand-substitution reactions of cis-(pip)(L)M(CO)_4 by L' (pip = piperidine; L, L' = CO, phosphines, phosphites; M = Cr, Mo) implicate square-pyramidal [(L)M(CO)_4], in which L occupies a coordination site in the equatorial plane, as the reactive species. In chlorobenzene (= CB) solvent, the predominant species formed after flash photolysis and a steady-state intermediate for the thermal reaction is cis—[(CB)(L)M(CO)_4], for which rates of CB-dissociation increase with increasing steric demands of coordinated L. Rates of CB-dissociation from trans-[(CB)(L)M(CO)_4] intermediates, formed after photolysis but not thermally, exhibit no observable dependence on the steric properties of the coordinated L.

Content: Graphene oxide (GO) is one of the most interesting nanomaterials in recent years. In order to explore its potential application in leather making process, a study on evaluating the effects of GO on the thermal stability and decomposition kinetics of bovine hide powders (HP) was performed by thermogravimetry. It was shown that the GO-doped hide powders (GO-HP) exhibit better thermal stability than those of raw hide powders. The kinetic and mechanism analysis of the decomposition stage used an integrated procedure involving model-free methods and universal master-plots method. Various methods were employed to calculate the activation energy of the fibers, including the Flynn-Wall-Ozawa (FWO), Modified Kissinger-Akahira-Sunose (MKAS) and Friedman methods. The activation energy values of GO-HP and raw hide powder were found to be 240.5 and 184.7 kJ/mol, respectively. Comparison of the experimental and theoretical master plots of various reaction mechanisms showed that when the conversion values are below 0.5, the most probable decomposition mechanism for HP and GO-HP is D1. Above 0.5, the decomposition mechanisms of HP and GO-HP are most probably described by A3 and R3 models, respectively. Take-Away: Graphene oxide (GO) doped hide powders (GO-HP) exhibit better thermal stability than those of raw hide powders. The activation energy values of GO-HP and raw hide powder were found to be 240.5 and 184.7 kJ/mol, respectively.

This diploma thesis is focused on the study of the thermal properties of high-performance fiber reinforced concrete HPFRC. The composites are based on a combination of steel and polymeric fibers. Typical properties of these materials include high mechanical strength, water resistence and salt penetration. HPFRCs are mainly used in the construction industry to build tall buildings. The differential transient method was used to study thermophysical variables. The theoretical part of the thesis described the types of concrete, their production, and their properties. Furthermore, thermophysical quantities and methods of their determination (stationary and transient methods, thermal analysis) are defined in the thesis. The aim of the thesis was to determine thermal properties, namely thermal conductivity and specific heat capacity. The results of the thesis can reveal changes in the composition of studied materials as well as critical temperatures for damaging the materials.

This diploma thesis deals with thermal qualities of moulding mixtures of foundry mould of various types of sand grains and a computer simulation of the solidification of the cast. The aim of this work is to compare the values of thermal qualities of moulding materials bonded with water glass taken in experimental measurements to the values of thermal qualities of moulding materials connected with organic binding agent contained in simulation software. A sample cast will be moulded in order to evaluate cooling capacities of individual moulding mixtures according the shift of thermal axis. These results will consequently be compared to the results of the simulation.