[Truncated abstract] This study was carried out to investigate the teaching and learning processes occurring in the topic of reaction mechanisms in three tertiary level organic chemistry courses and focussed on investigating perceptions about the importance of teaching and learning about reaction mechanisms and about the difficult aspects of the topic .... In the organic chemistry courses under investigation, students achieved many of the explicitly stated aims that their lecturers identified. The students rarely achieved implicit outcomes anticipated by the lecturer. Lecturers demonstrate a tendency to use particular structural representations when discussing certain types of reaction process. The study identified that students commonly use these same types when working through particular reaction processes. In addition, it was found that the use of a particular structure could cue students into thinking about only one type of reaction process taking place in a given reaction. The use of language that is consistent with a consideration of only single reaction particles was also commonly observed in lectures. While this can be adequate in some circumstances, other aspects of reaction processes are better considered in terms of multiple reaction particles ... The project proposes an integrated model, which takes into account the many levels (macroscopic, single particle molecular, multiple particle molecular and intramolecular) involved when describing reaction processes. It is felt that a consideration of the levels discussed in this model is useful when teaching and learning about reaction mechanisms.

This dissertation examines the motion of colloids in a temperature gradient, a non-equilibrium phenomenon also known as thermophoresis. Chapter 1 gives an introduction to the existing applications and basic concepts of thermophoresis and outlines some of the experimental and theoretical challenges that serve as a motivation for this PhD project. In Chapter 2, a general theoretical description for thermophoresis is formulated using the theory of non-equilibrium thermodynamics. The colloidal flux is split up into an interfacial single-colloid contribution and a bulk contribution, followed by a determination of transport coefficients based on Onsager’s reciprocal relations. It is further shown how the phenomenological expression of the thermophoretic flux can be recovered when the fluid is at steady-state. The results issuing from this description are then discussed and compared to other existing approaches, some of which are shown to neglect the hydrodynamic character of colloidal thermophoresis. Chapter 3 is dedicated to the validation of the introduced theoretical framework by means of computer simulations, using a simulation technique known as multi-particle collision dynamics. More specifically, the dependence of the thermophoretic force on different system parameters is examined and deviations from the theoretical prediction are explained by an advective distortion of interfacial fluid properties at the colloidal surface. Chapter 4 presents steady-state measurements of functionalised colloids in a temperature gradient, showing how the addition of molecular surface groups increases the experimental complexity of thermophoretic motion. The relaxation process behind this steady-state is also studied, to determine how the relaxation speed depends on the applied temperature gradient. In chapter 5, a general conclusion is drawn from the presented work and its implications are briefly discussed in relation to the current state of knowledge. Finally, the discussion is closed with an outlook on remaining challenges in understanding colloidal motion that could be the subject of future research.

Dans cette thèse, on étudie le phénomène de localisation d'Anderson des opérateurs de Schrödinger à N particules qui englobe aussi bien la localisation exponentielle des fonctions propres que la localisation dynamique. Dans un premier temps, on considère le modèle d'Anderson discret multi- particulaire avec un potentiel aléatoire à valeurs indépendantes et identiquement distribuées i.i.d. dont la distribution commune est au moins log-Höldérienne et une interaction de courte portée. On établit pour ce modèle la localisation d'Anderson pour les énergies susamment proches du bas du spectre après avoir montré qu'il est non-aléatoire. D'autre part, on montre que la localisation complète des systèmes mono- particulaires s'étend aux systèmes multi-particulaires ayant une interaction globale susamment faible et pour un désordre arbitraire. Pour ce résultat, l'existence d'une densité bornée de la distribution commune des variables aléatoires i.i.d. est nécessaire et on le montre pour des interactions ayant une forme très générale mais bornées. Les résultats sont démontrés à l'aide de l'adaptation aux systèmes multi- particulaires de l'analyse multi-échelle à énergie variable qui permet de traiter des distributions singulières contrairement à la méthode des moments fractionnaires. Les estimées de Wegner intervenant notamment dans l'analyse multi-échelle sont établies pour des cubes vériant une propriété de séparabilité en utilisant le Lemme de Stollmann. On démontre également l'estimée de Combes-Thomas qui joue un rôle important dans l'analyse des énergies extrêmes. / In this thesis, we study for the N-particles Schrodinger operators the Anderson localization phenomenon which consists of both exponential localization of eigenfunctions and dynamical localization. We rst consider the discrete multi-particle Anderson model with a short range interaction and a random potential whose values are independent and identically distributed i.i.d. with a log-Hölder continuous common probability distribution function. For such model, we show that the bottom of its spectrum is non-random and prove the Anderson localization for energies suciently close to the spectral edge. On the other hand, we establish that the complete localization from singleparticle systems extends to multi-particle systems with suciently weak interaction at arbitrary disorder and for absolute continuous probability distribution function of the i.i.d random variables. The results are proved by an adaptation to multi-particle systems of the vari- able energy multi-scale analysis which allows singular distributions instead of the fractional moments method. Wegner bounds, useful for the multi-scale analysis are proved for separable cubes using the Stollmann's Lemma. We also prove the Combes-Thomas estimate which plays an important role in the analysis of extreme energies.

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In this MSc thesis, it is investigated what parameters are relevant for describing energy consumption of heavy haul freight trains and how these can be used to develop key performance indicators (KPIs) for energy efficiency. The possible set of KPI is bounded by data available from energy meters used in electric IORE class locomotives hauling iron ore trains in northern Sweden. Furthermore, the analysis is only concerned with energy efficiency at the rolling stock level, excluding losses in the electric power supply network. Based on a literature study, parameters of interest describing driver, operations and rolling stock energy efficiency have been identified. By means of simulation, a parametric study is performed, simulating a 30 ton axle load iron ore train with 68 wagons. Train modelling input is obtained from technical documentation or estimated through measurements and statistical analysis. A multi-particle representation of the train is used to calculate gradient resistance for the simulation, which is also applied to determine the curve resistance.  Results show that the motion resistance is simulated quite accurately, while the lack of a driver model in the simulation tool leads to overestimation of energy consumption. Taking this into account, the importance of the driver for energy efficiency can still clearly be showcased in the parametric study. Especially on long steep downhill sections, prioritising the electric brakes over mechanical brakes is demonstrated to have a huge influence on net energy consumption, as has the amount of coasting applied. With the same driver behaviour in all simulations, the savings in specific energy from increasing axle load to 32.5 tons is estimated. Moreover, a comparison of increased train length and axle load points towards higher savings for the latter. In the end, parametric study results are used to recommend a structure for a monitoring system of energy efficiency based on a set of KPIs. With a sufficiently high sampling rate of energy meter data, it is adequate for calculating driver related KPIs and some additional KPIs. More KPIs can be tracked with access to additional data, e.g. cargo load. / I detta examensarbete undersöks vilka parametrar som är relevanta för att beskriva energiförbrukning för tunga godståg och hur dessa kan nyttjas för att utveckla nyckeltal för energieffektivitet. Antalet möjliga nyckeltal avgränsas till sådana som kan beräknas med data från elmätare som används i elektriska littera IORE lok som drar tunga malmtåg i norra Sverige. Vidare så tar analysen endast hänsyn till energieffektivitet för rullande materiel, vilket utesluter förluster i elektriska kraftmatningsnätet. Baserad på en litteraturstudie har relevanta parametrar som beskriver förare, drift och rullande materiel identifierats. Med hjälp av simuleringar av ett malmtåg med 30 tons axellast och 68 vagnar så utförs en parameterstudie. Indata för tågmodelleringen erhålls från teknisk dokumentation respektive uppskattas genom mätningar och statistisk analys. En representation av tåget som flertalet partiklar tillämpas i simulering för att beräkna lutningsmotståndet. Dessutom används densamma för att ta fram kurvmotståndet. Resultaten visar att gångmotstånd simuleras ganska exakt, medan avsaknad av en förarmodell i simuleringsvertyget leder till överskattad energiförbrukning. Med hänsyn tagen till detta så kan betydelsen av föraren för energieffektivitet fortfarande påvisas mycket tydligt i parameterstudien. I synnerhet i långa branta nedförsbackar har prioritering av den elektriska bromsen framför den mekaniska bromsen mycket stor påverkan på nettoenergiförbrukningen, likaväl som hur mycket tåget frirullar. Med samma förarbeteende i samtliga simuleringar har besparingar i specifik energiförbrukning kunnat uppskattats för en ökning av axellasten till 32,5 ton. Dessutom pekar en jämförelse av ökad tåglängd och axellast mot att sistnämnda ger större besparingar. Slutligen så har resultaten från parameterstudien nyttjats för att rekommendera en struktur för ett uppföljningssystem av energieffektivitet baserad på en uppsättning av nyckeltal. Med tillräckligt hög samplingsfrekvens på data från elmätare är den adekvat för att beräkna vissa nyckeltal, framförallt relaterad till förare. Fler nyckeltal kan följas upp med mer tillgänglig data så som lastvikter.