Les maisons individuelles reposant sur une formation argileuse considérée à moyen risque vis-à-vis des phénomènes de réhydratation et dessiccation des sols argileux, ont été particulièrement touchées par les tassements différentiels provoqués par le phénomène depuis les sécheresses de 2003 et 2005 en Gironde (33). Une première partie de la thèse a été de mener une étude sur le comportement gonflant et rétractant de la formation argileuse de Brach d’âge Plio-quaternaire, responsable de centaines de sinistres sur habitations à l’échelle d’un quartier puis à celle de la parcelle, à l’aide des paramètres géotechniques et mécaniques. Elle a mis en évidence l’hétérogénéité des faciès argileux et l’influence des passées sableuses à l’échelle de la formation argileuse. L’autre intérêt de ce travail est la compréhension des mécanismes et des cinétiques d’hydratation et de dessiccation des sols argileux jusqu’à 3 m de profondeur, sur un cycle annuel. L’étude est basée sur une méthode associant les données géophysiques aux valeurs des paramètres géotechniques obtenus in situ et en laboratoire. Ce couplage repose sur une instrumentation géotechnique et géophysique continue sur un site expérimental de la commune de Pessac (Gironde). L’intérêt de cette instrumentation est d’établir des corrélations entre les sollicitations mécaniques enregistrées par le sol (déplacements verticaux) en fonction de l’évolution de la teneur en eau volumique des sols jusqu’à 3 m de profondeur, reliée aux variations de résistivités électriques. Les travaux présentent les premiers résultats comparés entre les données géotechniques et les données géophysiques issues d’un dispositif de tomographie de résistivité électrique installé à demeure, aboutissant à l’obtention de gammes de résistivité électriques variables corrélées aux faciès rencontrés et à la teneur en eau des sols. / Homes built on sensitive clayey soils, considered as medium risk, are showing cracks evidencing differential movements occurring in their foundations after drought periods of 2003 and 2005. To address this problem in a first part of the thesis, the swell-shrinkage behaviour has been investigated specifically to the Plio-quaternary clayey formation of Brach, both at the scale of a district and a small land. The results reveal the variability of the clay behaviour when sandy lenses occurred inside the formation. The present work aims to assess geotechnical and compressibility parameters to analyse the variability of the swelling-shrinkage parameters inside a same clayey formation. The aim of a second part of this study is to identify the seasonal soil moisture variations occurring between wet period and dry summer down to 3 meter depth, using a new method integrating geophysical and geotechnical data obtained in situ and in laboratory. This research is based on the setting of an experimental site on Pessac town (Gironde) in order to monitor clayey behavior, to establish correlations between geotechnical properties, water content variations and electrical resistivity on soils over time and every month. The purpose is to survey and evaluate kinetics of soil water content evolution, temperature and vertical displacements down to 3 m depth. This work presents the first results which compare geotechnical, volumetric and electrical resistivity data by combining the field and laboratory measurements.

>Magister Scientiae - MSc / The present study investigates the strength of the hybridization by substituting Ce atom in Kondo lattice CeIn3 with Gd, Tb, and Dy and by changing the chemical environment around the Ce atom in substituting Pt with Ni in CePtSi2. This thesis covers four chapters outline as follows: Chapter 1 introduces the theoretical background in rare earths elements, and an overview of the physics of heavy-fermion and Kondo systems. Chapter 2 presents the experimental details used in this thesis. Chapter 3 report the effect of substituting Ce with moment bearing rare-earth elements RE = Gd, Tb and Dy in CeIn3, through x-ray diffraction (XRD) and electrical resistivity measurements

This study involved a comparative investigation of chloride-induced corrosion detection techniques on loaded reinforced concrete slabs which were exposed to deicing salts and wetting-drying cycles to simulate typical aggressive environments in cold climates. The studied techniques involved linear polarization technique, galvanostatic pulse technique, electrochemical impedance spectroscopy, half-cell potential and concrete electrical resistivity mapping. The results showed that concrete quality and moisture content have a direct effect on corrosion activity, and these properties are represented well with concrete electrical resistivity. The galvanostatic pulse technique was shown to correlate well with electrochemical impedance spectroscopy, which was used as a benchmark for corrosion rate measurements in this study; however, the galvanostatic pulse technique was not capable of detecting corrosion activity in saturated concrete accurately. The results of this research do not support the criteria provided by the ASTM C876-09 standard for using half-cell potentials to estimate the probability of reinforcing steel corrosion in reinforced concrete structures.

The tidal influence on the Big Pine Key saltwater/freshwater interface was analyzed using time-lapse electrical resistivity imaging and shallow well measurements. The transition zone at the saltwater/freshwater interface was measured over part of a tidal cycle along three profiles. The resistivity was converted to salinity by deriving a formation factor for the Miami Oolite. A SEAWAT model was created to attempt to recreate the field measurements and test previously established hydrogeologic parameters. The results imply that the tide only affects the groundwater within 20 to 30 m of the coast. The effect is small and caused by flooding from the high tide. The low relief of the island means this effect is very sensitive to small changes in the magnitude. The SEAWAT model proved to be insufficient in modeling this effect. The study suggests that the extent of flooding is the largest influence on the salinity of the groundwater.

La contamination par les hydrocarbures peut altérer les propriétés physicochimiques et biologiques du sous-sol, par conséquent le diagnostic et l’évolution des contaminants peuvent être surveillés en couplant les analyses géochimiques et les techniques géophysiques. Dans ce travail, différentes méthodes géophysiques de sub-surface telles que la tomographie de résistivité électrique, la polarisation induite, le géoradar et le potentiel spontané ont été utilisées d’une manière combinée pour localiser les zones impactées par les hydrocarbures du site de l’ancienne raffinerie de Petit Couronne. Les investigations géophysiques par la tomographie de résistivité électrique en 2D ont révélés la présence des anomalies de fortes valeurs de conductivité et chargeabilité électrique associés aux zones contaminées de l’aquifère. Les résultats obtenus avec les profils d’ERT et IP indiquent que la contamination a modifié les parties capacitives et ohmiques de la conduction électrique dans les sédiments contaminés. Cette signature très conductrice des zones contaminées est due aux processus de biodégradation des hydrocarbures qui minéralisent les eaux de l’aquifère. Les panaches d’hydrocarbures ont été identifiés sur les profils de géoradar par une forte atténuation des amplitudes de signaux électromagnétiques. Les profils de potentiel spontané ont aussi fourni une cartographie spatiale des zones contaminées par leurs signatures électriques négatives qui est associées aux processus d'oxydoréduction et biodégradation à l’interface entre la zone non saturée et saturée. Une carte de potentiel redox a été reconstruite à partir de l'inversion des données résiduelles de potentiel spontané grâce au calcul des composantes de la densité du courant électrique. La contribution redox dans l'aquifère contaminé s'explique par des dipôles verticaux répartis sur la frange capillaire juste au-dessus de la nappe phréatique, en favorisant le mécanisme de la biogéobatterie sur ce site. L’ensemble de ces résultats ont été confirmés par les mesures géochimiques menées au niveau des forages. L'étude a montré que les altérations biologiques des hydrocarbures ont modifié les propriétés chimiques de l'eau porale et que l'étendue de la contamination des eaux souterraines peut être délimitée à partir du contraste géophysique observé entre les zones contaminées et les zones non contaminées. La combinaison des différentes méthodes géophysiques avec des analyses géochimiques ponctuelles au niveau des forages ont permis de mieux comprendre les différents processus qui sont à l’origine de modifications des propriétés biogéochimiques dans les sols et les eaux souterraines. / The presence of hydrocarbon contamination in the subsurface can modify the physiochemical and biological properties of soil and groundwater. The sensitivity of geophysical methods to biogeochemical changes occurring in contaminated media can be used to monitor hydrocarbon contamination in a fast and inexpensive way. As such, geophysical methods including, electrical resistivity tomography, induced polarization, ground penetrating radar, self-potential and magnetic susceptibility were used in this work to characterize the hydrocarbon contamination and investigate its effects on the soil and groundwater geophysical and geochemical properties at a site impacted by an aged hydrocarbon plume. The geophysical response to hydrocarbon contamination varies according to factors related to the contaminant in question and to the contaminated environment. Therefore, to achieve a better interpretation, the field geophysical data were constrained by geochemical soil boring data which showed that biodegradation is occurring in the site. This was shown through observing elevated total dissolved solids concentrations, elevated groundwater electrical conductivity values, negative redox potential values and depleted terminal electron acceptors concentrations in the contaminated locations. Throughout the investigation, the geophysical measurements supported the conductive model and consistently recorded low resistivity anomalies, high chargeability values and attenuated GPR reflections in the contaminated zones. Additionally, significant negative self-potential anomalies associated with oxidation-reduction processes coupled to the biodegradation of hydrocarbons were recorded in the groundwater contaminated zone. Based on this observation, a redox potential map of the contaminated site was constructed by the inversion of the field self potential data. Throughout the process, a groundwater model was first calibrated to remove the electrokinetic component from the SP signal. Then, the obtained residual self potential data was inverted for the electrical current density by using an inversion algorithm which includes minimizing a cost function with a data misfit contribution and a regularizer. As a result, the obtained current density was used to construct a map of redox potential showing the borders and the redox front of the contaminant plume. The redox contribution was explained by vertical dipoles distributed across the capillary fringe, supporting further the mechanism of bio-geo-battery which was created due to the existence of a strong redox potential gradient between the highly reducing conditions within the plume and the oxidizing conditions outside the plume. Furthermore, elevated magnetic susceptibility values were recorded in the biologically active transition zone where bio-precipitation of iron minerals is occurring. Given these results, this study showed that biological alterations of hydrocarbons induced subtle changes in the pore water biogeochemistry, which consequently modified the geophysical properties of the contaminated sediments. The extent of groundwater contamination was delineated according to the geophysical contrast between the contaminated and clean zones. Moreover, the combination of the different geophysical methods, constrained by the geochemical point measurements, provided insight on the different processes which might have modified the soil and groundwater biogeochemical properties at the contaminated site.

Le stockage est la méthode de traitement des déchets non dangereux la plus communément utilisée dans le monde entier car elle est un moyen simple et économique pour leur élimination. Malgré une volonté nationale et européenne pour réduire le stockage de déchets biodégradables, une quantité non négligeable est encore enfouie entrainant la mise en place de modes de gestion spécifique. Autrefois exploitées comme de simples fosses de remplissage, les installations de stockage de déchets non dangereux (ISDND) sont aujourd’hui des ouvrages complexes dont l’objectif est de réduire l’impact environnemental et de valoriser énergétiquement le biogaz produit par la biodégradation de la matière organique. Afin d’accélérer les processus de biodégradation un casier de déchets peut être exploité en mode bioréacteur en réinjectant des lixiviats pour augmenter la teneur en eau des déchets. Le défi des années 2000 était de dimensionner et valider les systèmes de réinjection de lixiviat pour garantir une distribution optimale de la teneur en eau dans les massifs de déchets. Aujourd’hui, la question est de de suivre l’évolution de la biodégradation en tous points d’un massif pour notamment comprendre l’effet de ce mode de gestion. Les méthodes géophysiques en plus d’être non-destructives et spatialisantes sont utilisées depuis des années sur les ISDND et pourraient être sensibles à l’évolution de la biodégradation d’un massif de déchets, comme cela a été démontré pour la biodégradation d’autres milieux. Ainsi la problématique de cette thèse est d’évaluer la capacité de certaines méthodes géophysiques pour suivre l’évolution des paramètres bio-physico-chimiques d’un massif de déchets au cours de sa biodégradation. Un premier travail bibliographique a permis d’identifier quatre méthodes électriques parmi les méthodes géophysiques disponibles pour répondre à cette question :• La résistivité électrique• Le potentiel spontané• La polarisation provoquée• La polarisation provoquée spectraleAprès cet état de l’art, le travail de thèse a été séparé en trois parties. La première a été consacrée à la mise en place du suivi de ces quatre méthodes à l’échelle du laboratoire dans des conditions contrôlées, la seconde à analyser le suivi géophysique long terme sur le site industriel de la SAS Les Champs Jouault et la dernière a évaluée les observations à ces deux échelles. Enfin, la conclusion présente le potentiel de la méthode de mesure du potentiel provoquée comme la plus pertinente pour suivre l’évolution de la biodégradation d’un déchet non dangereux au cours du temps et aborde son utilisation dans un cadre industriel. / Storage is the most commonly used waste treatment method in the world because it is a simple and economical way to dispose of solid waste. Despite a national and European desire to reduce the storage of biodegradable waste, a significant amount is still buried, leading to the implementation of specific management methods. Formerly exploited as mere filling pits, MSWL are today complex structures whose objective is to reduce the environmental impact and energetically valorize the biogas produced by the biodegradation of organic matter. In order to accelerate biodegradation processes, a waste cell can be operated in bioreactor mode by reinjecting leachates to increase the water content of the waste. The challenge of the 2000s was to size and validate leachate re-injection systems to ensure optimal distribution of water content in the waste mass. Today, the question is to monitor evolution of the biodegradation in all points of a waste mass in particular to understand the effect of this management mode. Geophysical methods in addition to being non-destructive and spatializing have been used for years on MSWLs and could be sensitive to the evolution of a waste mass biodegradation, as has been demonstrated for the biodegradation of others environments. Thus the problematic of this thesis is to evaluate the capacity of certain geophysical methods to monitor the evolution of the bio-physicochemical parameters of a waste mass during its biodegradation. A first bibliographic work identified four electrical methods among the geophysical methods available to answer this question:• Electrical resistivity• Self potential• Time domain induced polarization• Spectral induced polarizationAfter this state of the art, the thesis work was separated into three parts. The first one was devoted to the implementation of the monitoring of these four methods at the laboratory scale under controlled conditions, the second to analyze the long-term geophysical monitoring at the industrial site of SAS Les Champs Jouault and the last one to evaluate the observations at these two scales. Finally, the conclusion presents the potential of time domain induced polarization method as the most relevant to monitor the evolution of a waste mass biodegradation over time and discusses its use in an industrial setting.

The diploma thesis deals with time-lapse electrical resistivity tomography (TL-ERT) of active slope deformations. Slope deformations represent one of the important land-forming processes. Frequently, they can cause considerable property damages and can endanger health and lives of inhabitants. Therefore, we can consider them as potentially dangerous so complete understanding of their dynamics, and their mechanisms of origin, is essential. Electrical resistivity tomography (ERT) then represents an effective geophysical tool for slope deformation investigation. Within diploma thesis, the evaluation of the several different time-series of the ERT measurements was performed. Based on findings of the one- year (August 1013 to July 2014) monitoring of resistivity changes by ERT, and also, based on daily and hourly recurrences of measured resistivity data, the optimum measuring interval has been determined, namely 12 hours. The most applicable electrode arrays and their combinations were suggested based on a testing of different electrode configurations. The results of detailed measurement with 1 m electrode spacing offered the idea of shortening of the total length of the present permanent TL-ERT profile as well as shortening the electrode spacing. These conclusions and proposed adjustments then resulted in...

Electroconductive silicate-based composites are advanced materials that allow building structures to perform several different functions simultaneously. Addressing the issues of their development and use is a suitable topic for research work. The aim of this work is to study the effect of structure on the resistivity of silicate composite. The structure of electrically conductive composites is studied on dry cement paste and mortar mixtures as well as on test bodies made of hardened cement paste and mortar after 28 days of curing. Based on the analysis of the raw materials, six suitable electroconductive fillers are selected based on particle size, resistivity, and water absorption. The parameters of dry cement paste and hardened cement paste with replacement of 4-19 wt. % cement by the selected fillers are determined. Two of the fillers are selected for use in dry and hardened mortar. Resistivity is determined for all dry mixes and hardened composites variants, and percolation thresholds are approximately determined. By studying the structure of the selected variants, it is shown that the most important parameters that have the greatest influence on the resistivity of the silicate composites are mainly the particle size and the intrinsic resistivity of the electrically conductive filler. For silicate composites in the hardened state, the volume of hydration products, especially portlandite and C-S-H gels, also has a significant influence. For both dry blends and hardened composites, it was found that the smaller the particle size of the electroconductive filler, the smaller the representation needed to reach the percolation threshold. Portlandite and C-S-H gels in the volume of the hardened composite cause its high resistivity. The resistivity of the hardened composite is always higher than that of the dry blends. Thus, the proportion of electroconductive filler needed to reach the percolation threshold is higher in hardened composites than in dry mixes. The resist

This doctoral thesis with the title “Possibilities of Detecting the Water Content in a Porous Medium Using the Method of Electrical Impedance Spectrometry introduces electrical impedance spectrometry (EIS) as an indirect electrical method of measurement and a tested apparatus for application in water management practice and in material engineering. A wide range of porous media in the area of water management have been narrowed within the preparation of this dissertation thesis to available samples of chiefly sandy soils and in material engineering to typical building materials, which are still solid burnt brick and timber. Measurement took place in the Laboratory of Water Management Research of the Department of Water Structures and in the Laboratory of the Department of Building Materials and Components at the Faculty of Civil Engineering of Brno University of Technology, in the Laboratory of Soil Mechanics of the company GEOtest, a.s. and in the Laboratory of the foreign university KU Leuven, KHBO in the City of Oostende, Belgium. The experiments performed required not only the production of special constructions of measuring probes and their connection, but also modifications of stations at which measurement was carried out. It is possible to use this doctoral dissertation thesis as a methodological manual of how to apply the measuring apparatus based on the EIS method in monitoring changes in the water content in selected porous media due to hydrodynamic stress imposed on it.

This thesis contains 2 parts (Part A and B) to fulfill the requirements for the degree of Master of Engineering. Part A: McMaster (on-campus) project. Part B: McMaster (industrial) project. / Part A abstract: The demodulation of analogue F.M. signals using frequency counting techniques is examined and implemented through the use of modern high speed T.T.L. integrated circuit technology. The entire demodulation unit was derived from exclusively digital components particularly compatible to frequency counting methods. The device was tested with carrier frequencies up to 2MHz and signal frequencies over the entire audio range with varying degrees of modulation. The main limitations appear to lay not in the hardware but in the actual counting technique itself which required quite large frequency deviations to resolve the higher audio frequency signals employed. Part B abstract: Investigation of SnO(2):B:Sb semiconductor species over the temperature range -60°C to +175°C reveals that electrical resistivity in this region is determined by the complex superposition of stable thin film scattering phenomena. Transient effects due to lattice imperfections inherent in the fabrication process start to "anneal” out at temperatures greater than 50°c and can be characterized by an activation energy of the order of .013 eV. Uncompensated samples doped heavily with boron illustrate a trend toward ionized impurity scattering at lower temperatures but mainly the species exhibits a complicated interplay of acoustical and optical phonon scattering modulated by doping level in such a manner as to lower T.C.R. An empirical expression relating resistivity-temperature behaviour to doping is developed. / Thesis / Master of Engineering (ME)