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Geostatistical techniques are used to estimate recoverable reserves at unsampled locations and to quantify uncertainty. Several variables are often measured and important for reserve evaluation. Using more variables improves the quality of modeling, but quantifying the relationships between the variables is difficult. The traditional linear model of coregionalization has been used to quantify the relationship between multiple variables, but ensuring the mathematical validity of the model is cumbersome. This research proposes an approximate method that improves the speed and practicality of the numerical modeling process by easily modeling multiple regionalized variables. The proposed algorithm is based on block LU simulation and takes local transformation into consideration. Application to a nickel deposit demonstrates the proposed methodology. / Mining Engineering

Nous avons étudié les collisions réactives O(1D) + CH4 et O(1D) + H2O d’intérêt atmosphérique et astrophysique à l’aide de méthodes de chimie quantique et de dynamique réactionnelle. Pour la première réaction, des calculs de dynamique quantique à l’aide d’une méthode indépendante du temps ont été entrepris sur une surface d’énergie potentielle existante en considérant CH3 comme un pseudo-atome. Cette approche à dimensionnalité réduite, qualifiée ici de modèle pseudo-triatomique, a permis d’obtenir les probabilités de réaction à un moment angulaire total nul (J=0), puis de calculer les sections efficaces et les taux de réaction par une méthode approchée de type J-shifting. Nos résultats quantiques ont été comparés aux résultats obtenus par une méthode quasi-classique de trajectoires et aux prédictions expérimentales. Ces comparaisons ont, entre autre, validé le fait que la voie de sortie OH + CH3 était la voie principale pour cette réaction. La seconde réaction O(1D) + H2O a été abordée d’un point de vue structure électronique. Nous avons caractérisé les grandes lignes de la surface d’énergie potentielle de H2O2 en tenant compte de tous les degrés de liberté avec une méthode de calcul de haut niveau (MRCI : Multi Reference Configuration Interaction). Ainsi, nous avons pu déterminer avec une grande précision les géométries, les fréquences et les énergies des isomères du système H2O2 ainsi que son diagramme énergétique. A l’avenir, il faudra construire une surface d’énergie potentielle qui sera utilisée pour décrire la dynamique de cette réaction. / We have studied the reactive collisions, O (1D) + CH4 and O (1D) + H2O, of atmospheric and astrophysical interest, using different quantum chemistry methods and reaction dynamics approaches. For the first reaction, quantum dynamical calculations using a time-independent method were carried out on an existing potential energy surface by considering CH3 as a pseudo-atom. This reduced dimensionality approach, i.e. a pseudo triatomic model, yielded the calculation of the reaction probabilities at zero total angular momentum (J = 0). The cross sections and reaction rates have been computed by the approximate J-shifting method. Our quantum results were compared with results obtained by a quasi-classical trajectory method and experimental predictions. These comparisons, among others, have enabled the fact that the channel CH3 + OH was the main exit channel for this reaction. The second reaction O(1D) + H2O has been studied at the level of electronic structure. We have characterized the outline of the potential energy surface of H2O2 , taking into account all the degrees of freedom at a high level calculation (MRCI: Multi Reference Configuration Interaction). Thus, we were able to determine with great accuracy the geometries, frequencies and energies of isomers of the H2O2 system and its energy diagram. In the future, a potential energy surface has to be built to be used in the dynamical calculations for this reaction.

The objective of this thesis research is to improve our understanding of the flow obstacle effect on heat transfer at supercritical and high subcritical pressures by experimentally studying the effect of different obstacles on heat transfer in two vertical upward-flow test sections: a 3-rod bundle and an 8 mm ID tube. The heat transfer measurements cover the region of interest of the Canadian Super-critical Water Cooled Reactor (SCWR). A thorough analysis of the obstacle effect on supercritical heat transfer (SCHT) was performed. In the 3-rod bundle, two types of obstacles were employed: wire wraps and low-impact grid spacers. Wire wraps were found to be more effective than grid spacers to enhance the SCHT. In the tubular test section, obstacles appeared to suppress the heat transfer deterioration (HTD) or decrease its severity; obstacles also generally enhanced the SCHT both in the liquid-like and the gas- like region. The experiment in the tubular test section revealed that, at certain flow conditions (low mass flux, low inlet subcooling), flow obstacles can have an adverse impact on the SCHT. A criterion to predict the onset of this adverse effect was developed. At high subcritical pressures, obstacles increased the CHF and reduced the maximum post-CHF temperature. A comparison of the experimental data with prediction methods for the SCHT, single phase heat transfer, CHF and post-dryout heat transfer was performed. Lastly, a new correlation to predict the enhancement in SCHT due to obstacles was developed for heat transfer in the liquid-like and gas-like regions.