Industrial effluents with high concentrations of heavy metals are widespread pollutants of great concerns as they are known to be persistent and non-degradable. Continuous monitoring and treatment of the effluents become pertinent because of their impacts on wastewater treatment plants. The aim of this study is to determine the correlation between heavy metal pollution in water and the location of industries in order to ascertain the effectiveness of the municipal waste water treatment plant. Heavy metal identification and physico-chemical analysis were done using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and multi-parameter probe respectively. Correlation coefficients of the measured values were done to investigate the effect of the industrial effluents on the treatment plants. Heavy metal resistant bacteria were identified and characterised by polymerase chain reaction and sequencing. Leeuwkuil wastewater treatment plants were effective in maintaining temperature, pH, and chemical oxygen demand within South Africa green drop and SAGG Standards whereas the purification plant was effective in maintaining the values of Cu, Zn, Al, temperature, BOD, COD, and TDS within the SANS and WHO standard for potable water. This findings indicated the need for the treatment plants to be reviewed.The industrial wastewater were identified as a point source of heavy metal pollution that influenced Leeuwkuil wastewater treatment plants and the purification plants in Vaal, Vereenining South Africa. Pseudomonas aeruginosa, Serratia marcescens, Bacillus sp. strain and Bacillus toyonensis that showed 100% similarity were found to be resistant to Al, Cu, Pb and Zn. These identified bacteria can be considered for further study in bioremediation. / Environmental Sciences / M. Sc. (Environmental Science)

The main aim of this thesis was the development of conjugation of existing methods for analysis of arsenic-glutathione complexes (As-GS complexes) together with simple arsenic species (iAs, MMAs, DMAs) during simple run. The basic technique for analysis of As-GS complexes was the HPLC-ICP-MS method with a reverse phase separation column (C18). The separation problem of simple species has been overcome by extending of system by postcolumn hydride generation with cryotrapping system (HG-CT). The resulting HPLC/HG-CT-ICP-MS system provides a complex analysis of all the above-mentioned analytes. According to the currently available resources, it is an innovative system, where for the first time all the simple arsenic species (iAs, MMAs, DMAs) and the As-GS complexes were separated. Under the given conditions, the detection limit for the As-GS complexes of 1.9 pg cm-3 in the RP-HPLC-ICP-MS system (a quantification limit of 6.5 pg cm-3 ) was achieved at a sensitivity of 468 CPS s pg-1 . The HG-CT-ICP-MS system provided a detection limit for iAs of 1.2 pg cm-3 at a sensitivity of 1121 CPS s pg-1 , for MMAs of 0.043 pg cm-3 at a sensitivity of 895 CPS s pg-1 and for DMAs of 0.076 pg.cm-3 at a sensitivity of 926 CPS s pg-1 . This method was applied to achieve another aim, studying the pathways of enzymatic...

Les interactions entre particules dans les gaz quantiques ultrafroids peuvent être contrôlées à l'aide de résonances de Fano-Feshbach. Ces résonances de diffusion se produisent lors de collisions à basse énergie entre deux atomes et sont généralement obtenues à l'aide d'un champ magnétique statique externe. Elles font des gaz atomiques ultrafroids un terrain d'exploration pour la recherche de nouvelles phases dans lesquelles la physique quantique joue un rôle clef.Le travail présenté dans ce mémoire s'inscrit dans le cadre de la recherche de telles phases.Ce manuscrit comporte deux parties. La première est consacrée à l'étude de bosons composites obtenus dans des gaz de Fermi hétéronucléaires 2D. Nous étudions le diagramme de phase de ce système à T = 0 et nous mettons en évidence une transition de phase gaz-cristal. Nos résultats sont prometteurs en vue d'expériences futures avec le mélange 6Li-40K.Dans la seconde partie, nous proposons un nouveau type de résonance de Fano-Feshbach. Le couplage à l'origine de cette résonance est obtenu à l'aide d'un champ magnétique micro-onde.Notre méthode s'applique à n'importe quelle espèce atomique dont l'état fondamental est clivé par l'interaction hyperfine. Elle ne nécessite pas l'utilisation d'un champ magnétique statique.Nous décrivons d'abord ces résonances à l'aide d'un modèle simple à deux niveaux. Ensuite, nous les caractérisons numériquement à l'aide de notre propre programme implémentant l'approche multi-canaux des collisions atomiques. Nos résultats ouvrent des perspectives optimistes en vue de l'observation des résonances de Feshbach induites par un champ micro-onde avec les atomes alcalins bosoniques suivants : 23Na, 41K, 87Rb et 133Cs. / The interparticle interactions in ultracold atomic gases can be tuned using Fano-Feshbach scattering resonances, which occur in low-energy collisions between two atoms. These resonances are usually obtained using an external static magnetic field. They turn ultracold atomic gases into an experimental playground for the investigation of novel phases in which Quantum Physics plays a key role. The work presented in this memoir is part of the theoretical effort towards the search for yet unexplored quantum phases.This manuscript is organised in two parts. The first one is devoted to composite bosons formed in a 2D heteronuclear Fermi gas. We characterise the zero-temperature phase diagram and show the gas-crystal phase transition in this system. Our results are promising in view of future experiments with the 6Li-40K mixture.In the second part, we propose an alternative to static-field Fano-Feshbach resonances. The idea is to achieve the coupling by using a resonant microwave magnetic field. Our scheme applies to any atomic species whose ground state is split by the hyperfine interaction. It does not require the use of a static magnetic field. First, these resonances are presented using a simple two-channel model. We then characterise them numerically using our own full-edged implementation of the coupled-channel approach. Our results yield optimistic prospects for the observation of microwave-induced Fano-Feshbach resonances with the bosonic alkali atoms 23Na, 41K, 87Rb, and 133Cs.

Les infrastructures de transport est essentielle au maintien et à l'expansion des activités sociales et économiques dans les régions circumpolaires. À mesure que le climat se réchauffe, la dégradation du pergélisol sous les remblais a entraîné de graves dommages structuraux à la route, entraînant une augmentation importante des coûts d'entretien et une réduction de la durée de vie des infrastructures. Pendant ce temps, l'advection de chaleur déclenchée par les écoulements d’eau souterrains peut altérer le bilan énergétique du remblai et du pergélisol sous-jacent et modifier le régime thermique des remblais routiers. Cependant, peu de recherches ont été effectuées pour comprendre la synergie entre les processus thermiques de surface et souterrains des remblais routiers des régions froides. L'objectif de cette recherche était de comprendre les interactions thermiques entre l'atmosphère, le remblai routier, les écoulements d’eau et le pergélisol dans le contexte du changement climatique. Cette base, de connaissances est nécessaire pour la conception technique, l'entretien des routes et l'évaluation de la vulnérabilité des infrastructures. Les travaux de recherche ont permis de développer de nouvelles méthodes d'analyse thermique pour caractériser et identifier le rôle de l'advection thermique sur le changement de température d'un remblai routier expérimental au Yukon (Canada) en termes d’intensité, de vitesse et de profondeur de l'impact thermique. Les résultats montrent que l'augmentation de la température due aux flux de chaleur advectifs déclenchés par l’écoulement d'eau peut être jusqu'à deux ordres de grandeur plus rapide qu'en raison du seul réchauffement atmosphérique. La recherche a ensuite présenté un bilan énergétique de surface pour quantifier la quantité d'énergie entrant dans le centre et la pente du remblai avec des épaisseurs et des propriétés de neige variables. Le tout a été appuyé par des observations géothermique de plusieurs années et une grande quantité de données météorologiques. Les résultats illustrent que le bilan énergétique de surface est principalement contrôlé par le rayonnement net et moins par le flux de chaleur sensible. Le flux de chaleur transmis à la pente du remblai diminue de façon exponentielle avec l'augmentation de l'épaisseur de la neige et diminue de façon linéaire avec l’installation du couvert de neige et la longueur de la période d’enneigement. De plus, un modèle de bilan énergétique de surface et un modèle cryohydrologique entièrement couplé ont été développés pour étudier l'impact thermique de l'advection de chaleur associée à l'écoulement de l'eau souterraine sur le dégel du pergélisol et le développement de taliks (c.-à-d. zone perpétuellement non gelée dans les zones de pergélisol). Le modèle couplé a réussi à reproduire la tendance à la hausse du plafond du pergélisol (erreur absolue moyenne <0,2 m) au cours de la période 1997-2018. Les résultats montrent que l'advection de chaleur a fourni une source d'énergie supplémentaire pour accélérer le dégel du pergélisol et a doublé le taux d’augmentation de l’épaisseur de la couche active 0,1 m·a-1 à 0,19 m·a-1, par rapport au scénario où aucun écoulement d'eau ne se produit. Le talik s'est initialement formé et développé en fonction du temps sous l’effet combiné des écoulement d’eau, de l'isolation de la neige, de la construction de la route et du réchauffement climatique. Le débit d'eau souterraine a relié des corps isolés de talik et a amené le remblai de la route dans un état thermique irréversible, en raison de la rétroaction de l'eau liquide (effet de chaleur latente) piégée dans le talik. Ces résultats montrent l'importance de l'advection de chaleur induite par l'écoulement d'eau sur le régime thermique de la sous-couche (c.-à-d. la couche de matériau de remblai) et du sous-sol (c.-à-d. le matériau natif sous un remblai) du remblai lorsque le remblai routier intercepte le drainage local. De plus, les résultats obtenus soulignent la nécessité de coupler les processus thermiques de surface et souterrains dans le but d'évaluer la stabilité thermique des routes subarctiques. / Transportation infrastructure is crucial to maintaining and expanding the social and economic activities in circumpolar regions. As the climate warms, degradation of the permafrost causes severe structural damages to the road embankment, leading to large increases in maintenance costs and reductions in its lifespan. Meanwhile, heat advection triggered by mobile water flow can alter energy balance of the embankment and underlying permafrost and modify the thermal regime of road embankments. However, little research has been done to understand the synergy between surface and subsurface thermal processes of cold region road embankments. The overall goal of this research was to elucidate thermal interactions between the atmosphere, the road embankment, mobile water flow, and permafrost within the context of climate change. This knowledge is needed for engineered design, road maintenance, and infrastructure vulnerability assessment. The research first used new thermal analysis to characterize and identify the role of heat advection on temperature change of an experimental road embankment, Yukon, Canada in terms of magnitude, rate and thermal impact depth. It shows that soil temperature increase due to advective heat fluxes triggered by mobile water flow can be up to two orders of magnitude faster than due to atmospheric warming only. The research then presented a novel surface energy balance to quantify the amount of ground heat flux entering the embankment center and slope with varying snow depth and properties, supported by multi-year thermal and meteorological observations. My results illustrate that the surface energy budget is mainly controlled by net radiation, and less by the sensible heat flux. The ground heat flux released at embankment slope exponentially decreased with the increase of snow depth, and was linearly reduced with earlier snow cover and longer snow-covered period. A fully integrated surface energy balance and cryohydrogeological model was implemented to investigate the thermal impact of heat advection associated with subsurface water flow on permafrost thaw and talik (i.e., perennially unfrozen zone in permafrost areas) development. The integrated model successfully reproduced the observed increasing trend of the active layer depth (mean absolute error < 0.2 m) over the 1997-2018 period. The results show that heat advection provided an additional energy source to expedite permafrost thaw, doubling the increasing rate of permafrost table depth from 0.1 m·a-1 to 0.19 m·a-1, compared with the scenario where no water flow occurs. Talik formation and development occurred over time under the combined effect of subsurface water flow, snow insulation, road construction and climate warming. Subsurface water flow connected isolated talik bodies and triggered an irreversible thermal state for the road embankment, due to a local feedback mechanism (latent heat effect) of trapped, unfrozen water in talik. These findings elucidate the importance of heat advection induced by mobile water flow on the thermal regime of embankment subbase (i.e., a layer of fill material) and subgrade (i.e., the native material under an embankment) when the road embankment intercepts the local drainage. Furthermore, the obtained results emphasize the need to couple surface and subsurface thermal processes to evaluate the thermal stability of sub-Arctic roads.

Le virus de la stomatite vésiculaire (VSV) sert de modèle pour l'étude de la multiplication des virus (Mononegavirales) alors que la rage(RV) reste un sérieux problème de santé publique. Le génome de VSV et RV code notamment la nucléoprotéine (N) et la phosphoprotéine (P). N s'associe étroitement à l'ARN viral. Ce complexe N-ARN sert de matrice pour la réplication et la transcription virale. P est le cofacteur de la polymérase virale (L) et chaperonne N. En interagissant avec N-ARN (domaine C-terminal) et avec L (domaine N-terminal), P assure le lien physique entre l'ARN viral et L. La stœchiométrie de P, sa structure et son rôle exact pendant la transcription et la réplication restent incertains. Mon travail a consisté à une caractérisation biophysique et structurale de P et des complexes N-ARN-P pour mieux comprendre la dynamique du complexe de réplication de ces virus.<br />L'analyse biophysique montre que P RV & VSV existent sous forme de dimère allongé en solution. L'analyse bioinformatique a révélé une organisation modulaire, confirmé par des études biochimiques et biophysiques de mutants de P RV. La structure du domaine C-terminal de P VSV a été résolue par RMN et montre une homologie celle du C-ter de P RV. La caractérisation de l'interaction entre P et les anneaux N-ARN a révélé l'existence de deux types de complexes N-ARN-P (contenant un et 2 dimères de P par anneau). L'étude par ME des complexes nucléocapsides-P a permis de mettre en évidence un changement de conformation important.<br />Pour devenir accessible à L, l'ARN viral doit se dissocier localement de N. L'interaction N-ARN-P représente potentiellement une nouvelle cible pour le développement d'antiviraux.

Analyses of nuclear reactor safety have increasingly required coupling of full three dimensional neutron kinetics (NK) core models with system transient thermal–hydraulics (TH) codes.  In order to produce results within a reasonable computing time, the coupled codes use two different spatial description of the reactor core.  The TH code uses few, typically 5 to 20 TH channels, which represent the core.  The NK code uses explicit one node for each fuel assembly.  Therefore, a spatial mapping of a coarse grid TH and a fine grid NK domain is necessary.  However, improper mappings may result in loss of valuable information, thus causing inaccurate prediction of safety parameters. The purpose of this thesis is to study the effectiveness of spatial coupling (channel refinement and spatial mapping) and develop recommendations for NK/TH mapping in simulation of safety transients.  Additionally, sensitivity of stability (measured by Decay Ratio and Frequency) to the different types of mapping schemes, is analyzed against OECD/NEA Ringhals–1 Stability Benchmark data. The research methodology consists of spatial coupling convergence study, by increasing the number of TH channels and varying mapping approaches, up to and including the reference case.  The reference case consists of one-to-one mapping: one TH channel per one fuel assembly.  The comparisons of the results are done for steady–state and transient results.  In this thesis mapping (spatial coupling) definition is formed and all the existing mapping approaches were gathered, analyzed and presented.  Additionally, to increase the efficiency and applicability of spatial mapping convergence, a new mapping methodology has been proposed.  The new mapping approach is based on hierarchical clustering method; the method of unsupervised learning that is adopted by many researchers in many different scientific fields, thanks to its flexibility and robustness.  The proposed new mapping method turns out to be very successful for spatial coupling problem and can be fully automatized allowing for significant time reduction in mapping convergence study. The steady–state results obtained from three different plant models for all the investigated cases are presented.  All models achieved well converged steady–state and local parameters were compared and it was concluded that solid basis for further transient analysis was found.  Analyzing the mapping performance, the best predictions for steady–state conditions are the mappings that include the power peaking factor feature alone or with any combination of other features.  Additionally it is of value to keep the core symmetry (symmetry feature).  The big part of this research is devoted to transient analysis.  The selection of transients was done such that it covers a wide range of transients and gathered knowledge may be used for other types of transients.  As a representative of a local perturbation, Control Rod Drop Accident was chosen.  A specially prepared Feedwater Transient was investigated as a regional perturbation and a Turbine Trip is an example of a global one.  In the case of local perturbation, it has been found that a number of TH channels is less important than the type of mapping, so a high number of TH channels does not guarantee improved results.  To avoid unnecessary averaging and to obtain the best prediction, hot channel and core zone where accident happens should be always separated from the rest.  The best performance is achieved with mapping according power peaking factors, and therefore this one is recommended for such type of perturbation. The regional perturbation has been found to be more challenging than the others.  This kind of perturbation is strongly dependent on mapping type that affects the power increase rate, SCRAM time, onset of instability, development of limit cycle, etc.  It has been also concluded that a special effort is needed for input model preparation.   In contrast to the regional perturbation, the global perturbation is found to be the least demanding transient.  Here, the number of TH channels and type of mapping do not have significant impact on average plant behaviour – general plant response is always well recreated.  A special effort has also been paid to investigate the core stability performance, in both global and regional mode.  It has been found that in case of unstable cores, a low number of TH channels significantly suppresses the instability.  For these cases number of TH channels is very important and therefore at least half of the core has to be modeled to have a confidence in predicted DR and FR.  In case of regional instability in order to get correct performance of out-of-phase oscillations, it is recommended to use full-scale model.  If this is not possible, the mapping which is a mixture of 1st power mode and power peaking factors, should be used. The general conclusions and recommendations are summarized at the end of this thesis.  Development of these recommendations was one of the purposes of this investigation and they should be taken into consideration while designing new coupled TH/NK models and choosing mapping strategy for a new transient analysis. / <p>QC 20130516</p>

The gastrointestinal tract (GIT) regulates nutrient uptake, secretes hormones and has a crucial gut flora and enteric nervous system. Of relevance for these functions are the G protein-coupled receptors (GPCRs) and the solute carriers (SLCs). The Adhesion GPCR subfamily is known to mediate neural development and immune system functioning, whereas SLCs transport e.g. amino acids, fatty acids (FAs) and drugs over membranes. We aimed to comprehensively characterize Adhesion GPCR and SLC gene expression along the rat GIT. Using qPCR we measured expression of 78 SLCs as well as all 30 Adhesion GPCRs in a twelve-segment GIT model. 21 of the Adhesion GPCRs had a widespread (≥5 segments) or ubiquitous (≥11 segments) expression. Restricted expression patterns were characteristic for most group VII members. Of the SLCs, we found the majority (56 %) of these transcripts to be expressed in all GIT segments. SLCs were predominantly found in the absorption-responsible gut regions. Both Adhesion GPCRs and SLCs were widely expressed in the rat GIT, suggesting important roles. The distribution of Adhesion GPCRs defines them as a potential pharmacological target. FAs constitute an important energy source and have been implicated in the worldwide obesity increase. FAs and their ratios – indices for activities of e.g. the desaturase enzymes SCD-1 (SCD-16, 16:1n-7/16:0), D6D (18:3n-6/18:2n-6) and D5D (20:4n-6/20:3n-6) – have been associated with e.g. overall mortality and BMI. We examined whether differences in FAs and their indices in five lipid fractions contributed to obesity susceptibility in rats fed a high fat diet (HFD), and the associations of desaturase indices between lipid fractions in animals on different diets. We found that on a HFD, obesity-prone (OP) rats had a higher SCD-16 index and a lower linoleic acid (LA) proportions in subcutaneous adipose tissue (SAT) than obesity-resistant rats. Desaturase indices were significantly correlated between many of the lipid fractions. The higher SCD-16 may indicate higher SCD-1 activity in SAT in OP rats, and combined with lower LA proportions may provide novel insights into HFD-induced obesity. The associations between desaturase indices show that plasma measurements can serve as proxies for some lipid fractions, but the correlations seem to be affected by diet and weight gain.

Die vorliegende Arbeit beschreibt die Entwicklung und Charakterisierung eines mikromechanischen kraftgekoppelten Schwingsystems für die resonante Detektion niederfrequenter Schwingungen. Es wird ein neuartiges Prinzip vorgestellt, das es ermöglicht, niederfrequente Vibrationen frequenzselektiv zu erfassen. Mittels Amplitudenmodulation wird das niederfrequente Signal in einen höheren Frequenzbereich umgesetzt. Durch Ausnutzung der mechanischen Resonanzüberhöhung wird aus dem breitbandigen Signal ein schmales Band herausgefiltert, die anderen Frequenzbereiche werden unterdrückt. Auf diese Weise wird direkt die spektrale Information des niederfrequenten Signals gewonnen. Eine Fourier-Transformation ist hierbei nicht notwendig. Die Abstimmung des Sensors erfolgt über eine Wechselspannung und führt dadurch zu einer einfachen Auswertung. Die Schwerpunkte der Arbeit liegen in den theoretischen Untersuchungen zum neuartigen Sensorprinzip, in der Entwicklung einer mikromechanischen Sensorstruktur zum Einsatz des neuen Prinzips sowie in der Entwicklung und Charakterisierung eines Messsystems zur Detektion niederfrequenter mechanischer Schwingungen mit dem neuen Sensor. / This thesis describes the development and characterization of a micromechanical force coupled oscillator system for the resonant detection of low frequency vibrations. It presents a novel working principle that enables spectral measurements of low frequency vibrations. The low frequency spectral content is converted into a higher frequency range by means of amplitude modulation. Due to the mechanical resonance a narrow band is filtered out of the wide band vibration signal. The remaining frequency content is suppressed. Hence, the spectral information is directly obtained with the sensor system without a fast Fourier transform. The tuning is done with an AC voltage resulting in a simple analysis. The main focuses of the work are the theoretical analysis of this novel sensor principle, the development of the micromechanical sensor structure for the use of the novel principle as well as the development and characterization of a measurement system for the spectral detection of low frequency mechanical vibrations with the developed sensor system.

The electromagnetic coupling of a microstrip transmission line (MS-TL) to a metamaterial backward wave Negative-Refractive-Index transmission line (NRI-TL) is the primary investigation of this dissertation. The coupling of forward waves in the MS-TL to the backward waves in the NRI-TL results in the formation of complex modes, characterized by simultaneous phase progression and attenuation along the lossless lines. Through network-theoretic considerations, we investigate the properties of these modes in the complex-frequency plane of the Laplace domain to help unravel the confusion that has existed in the literature regarding the independent excitation of a pair of conjugate complex modes. We show that it is possible to arbitrarily suppress one of the modes over a finite bandwidth and completely eliminate it at a discrete set of frequencies using proper source and load impedances. Hence we use conjugate modes with independent amplitudes in our eigenmode expansion when we analyse various coupling configurations between the two types of lines (MS/NRI-TL coupler). We derive approximate closed-form expression for the scattering parameters of the MS/NRI-TL coupler and these are complemented by design charts that allow the synthesis of a wide range of specifications. Moreover, these expressions reveal that such couplers allow for arbitrary backward coupling levels along with very high-isolation when they are made half a guided wavelength long. The MS/NRI-TL coupler offers some interesting applications which we highlight through the design and testing of a 3-dB power splitter, a high-directivity signal monitor and a compact corporate power divider. We have included design, simulation and experimental data for the fabricated prototypes exhibiting good agreement and thereby justifying the theory that has been developed in this work to explain the coupling between a right-handed MS-TL and a left-handed NRI-TL.

The electromagnetic coupling of a microstrip transmission line (MS-TL) to a metamaterial backward wave Negative-Refractive-Index transmission line (NRI-TL) is the primary investigation of this dissertation. The coupling of forward waves in the MS-TL to the backward waves in the NRI-TL results in the formation of complex modes, characterized by simultaneous phase progression and attenuation along the lossless lines. Through network-theoretic considerations, we investigate the properties of these modes in the complex-frequency plane of the Laplace domain to help unravel the confusion that has existed in the literature regarding the independent excitation of a pair of conjugate complex modes. We show that it is possible to arbitrarily suppress one of the modes over a finite bandwidth and completely eliminate it at a discrete set of frequencies using proper source and load impedances. Hence we use conjugate modes with independent amplitudes in our eigenmode expansion when we analyse various coupling configurations between the two types of lines (MS/NRI-TL coupler). We derive approximate closed-form expression for the scattering parameters of the MS/NRI-TL coupler and these are complemented by design charts that allow the synthesis of a wide range of specifications. Moreover, these expressions reveal that such couplers allow for arbitrary backward coupling levels along with very high-isolation when they are made half a guided wavelength long. The MS/NRI-TL coupler offers some interesting applications which we highlight through the design and testing of a 3-dB power splitter, a high-directivity signal monitor and a compact corporate power divider. We have included design, simulation and experimental data for the fabricated prototypes exhibiting good agreement and thereby justifying the theory that has been developed in this work to explain the coupling between a right-handed MS-TL and a left-handed NRI-TL.