Over several centuries, mining activities have resulted in the creation of varied environmental complications. Most mining activities are carried out in locations with proximity to human settlements. The interplay of mining activity and society has created  several mining-related conflicts throughout the world, and in developing countries especially, these conflicts are much prevalent. These conflicts could be analysed in a variety of ways: analyzing the conflicts based on goals, interests and value interference; or on the bases of issues related to interaction between two or more parties. This paper takes into consideration the two concepts of constructivity and destructivity of conflicts as they relate to natural resource management and indicate that it is possible for a country or society like Ghana to discover constructive potential in a phenomenon that is mostly deemed destructive. The conflict situations in two mining communities (Akyem and Wassa) are taken into consideration for this paper. This does not deal with issues of conflict management, rather, it takes a look into the interaction between these communities and the associated mining company to determine whether the relationship between them possess constructive or destructive potentials. Based on interviews and information available on the internet, this paper determines that there exist elements of constructivity and destructivity in both areas. In the Akyem area, the destructive aspects reside in the relationship between Newmont and the Wassa Association of Communities Affected by Mining (WACAM). The relationship between Newmont and the local representatives take on a constructive aspect. Even though there is some sort of tension between the local people and Newmont, the situation can still be considered as constructive because they are still able to engage in dialogue in an attempt to coexist. In the Wassa area on the other hand, the story is different thus taken a destructive nature between Golden Star Resources and the communities. The involvement of the government however presents an opportunity for constructivity in the situation.

The Lautens group has a long-standing interest in developing novel approaches to heterocycle synthesis. One such approach is a Pd-catalyzed, norbornene-mediated domino reaction which can form up to three carbon-carbon bonds in one synthetic sequence. The key additive is norbornene which acts similar to a catalyst by assembling the scaffold to enable the formation of a carbon-carbon bond, though is not incorporated into the final compound. The reaction involves C-H bond functionalization as a key step and a Pd(IV) complex as a key intermediate. The goal of the current thesis was to introduce reactive heteroatoms to this domino reaction for the first time, with particular focus on the introduction of nitrogen. Methodologies were developed to present novel syntheses of heterocycles with high pharmaceutical interest. Our initial study focused on the selective functionalization of thiophenes to give multi-substituted sulfur compounds. To synthesize pharmaceutically important nitrogen heterocycles, we demonstrated for the first time that an amination reaction was compatible with the domino reaction. This development led to novel approaches to synthesize substituted indolines, indoles, tetrahydroquinolines, benzomorpholines, phenoxazines, dihydrodibenzoxazepines, tetrahydroisoquinolines, tetrahydroisoquinolinones and tetrahydrobenzazepines. In contrast to the use of norbornene in a catalytic manner, we demonstrated that heterocycles could also be synthesized by the incorporation of strained alkenes. We developed a conceptually novel approach to generate nitrogen heterocycles by using norbornadiene as an acetylene synthon. A palladium-catalyzed annulation of substituted haloanilines with norbornadiene led to functionalized indolines. These indolines could be rapidly converted to benzenoid-substituted indoles and tricyclic indolines, which form the core of many biologically active compounds. Extension to the use of substituted halobenzamides led to functionalized isoquinolinones. Finally, we embarked on a study to perform selective palladium-catalyzed C-H functionalization reactions with N-iodoarylpyrroles and strained alkenes. We will present the reaction conditions necessary to favour aryl C-H functionalization over pyrrole C-H functionalization.

This thesis utilized pulse shaping technology to study chirp response of SSBR and attempt to analyze contribution of SSBR in mode-locked process. A home-made pulse shaping system (based on 4f scheme) with Freezing algorithm and Gerchberg-Saton algorithm was demonstrated. A normal dispersion at nonabsorbable wavelength and an anomalous dispersion around absorbable wavelength region in SSBR were obtained. Meanwhile, a Kramers-Kronig relation like behavior of pulse depression/broadening ratio in the strained multiple quantum well was observed and also refer to that pulse starting force is stronger at short wavelength. Decrease of pulse compression with increasing power of negative chirp incident pulse was characterized. Unclear power dependence for positive chirp case was also performed. These could be due to competition of band-filling and pump dump process. In addition, higher reflectivity and tendency of lower saturation fluence of SSBR for negative chirp incident pulse were observed.

Two SiGe-on-insulator (SGOI) structures for CMOS application are presented: surface-channel strained-Si on SGOI (SSOI) and dual-channel SGOI structures. Comparisons between two structures are made from both device performance and CMOS process point of view. We have demonstrated both structures on SGOI, and have fabricated n-MOSFET’s and p-MOSFET’s on those two structures respectively. Device characteristics are presented. The devices show enhancement on both electron and hole mobilities. / Singapore-MIT Alliance (SMA)

Dans ce travail, une configuration laminaire stratifiée est utilisée afin d’étudier les caractéristiques de la pyrolyse et de l’oxydation du charbon pulvérisé dans un mélange de flux réactif à la fois dans les conditions atmosphériques conventionnelles et dans des conditions de combustion enrichie en oxygène. Deux diagnostics optiques, la spectroscopie d’émission de flamme et la mesure de l’émission spontanée sont utilisés pour caractériser la structure de la flamme. Les profiles de concentration de trois radicaux excités, OH*, CH* and C*2 sont mesurés et analysés.Des simulations 1-D utilisant la cinétique détaillée y compris des sous-mécanismes de OH*, CH* and C*2 et de combustion de charbon sont effectuées et comparées avec des données expérimentales. La comparaison qualitative a montré que la configuration numérique actuelle était appropriée pour la prédiction des émissions de OH*, CH* and C*2. Les résultats prédits par l’approche numérique diffèrent avec les modifications apportées aux sous-modèles de charbon et aux paramètres cinétiques. Le modèle de pyrolyse et les matières volatiles semblent jouer des rôles plus importants. / In the present work, a laboratory-scale laminar strained configuration is used to investigate the characteristics of pulverized coal devolatilization and oxidation in a mixture of CH4/O2/N2 reactive flow both in conventional air conditions and in oxygen-enriched combustion conditions. Two optical diagnostics, Flame Emission Spectroscopy and measurement of spontaneous emission, are employed for the characterization of flame structure. The spatial concentration evolution of three excited radicals, OH*, CH*and C*2 , are measured and analyzed.1-D simulations using detailed gas-phase kinetics including OH*, CH*, and C*2 sub-mechanisms and coal combustion submodels are performed and compared with experimental data. Qualitative comparison with experiments showed that the current numerical configuration was suitable for the prediction of OH*, CH* and C*2 emission. The predicted results differed with changes to the coal sub-models and kinetic parameters. The devolatilization model and volatile matters seem to play more important roles.

Regular physical activity improves insulin action and is an effective therapy for the treatment and prevention of type 2 diabetes. However, little is known of the mechanisms by which exercise improves insulin action in muscle. These studies investigate the actions of a single bout of exercise and short-term endurance training on insulin signalling. Twenty-four hours following the completion of a single bout of endurance exercise insulin action improved, although greater enhancement of insulin action was demonstrated following the completion of endurance training, implying that cumulative bouts of exercise substantially increase insulin action above that seen from the residual effects of an acute bout of prior exercise. No alteration in the abundance and phosphorylation of proximal members of the insulin-signalling cascade in skeletal muscle, including the insulin receptor and IRS-1 were found. A major finding however, was the significant increase in the serine phosphorylation of a known downstream signalling protein, Akt (1.5 fold, p ≤0.05) following an acute bout of exercise and exercise training. This was matched by the observed increase in protein abundance of SHPTP2 (1.6 fold, p ≤0.05) a protein tyrosine phosphatase, in the cytosolic fraction of skeletal muscle following endurance exercise. These data suggest a small positive role for SHPTP2 on insulin stimulated glucose transport consistent with transgenic mice models. Further studies were aimed at examining the gene expression following a single bout of either resistance or endurance exercise. There were significant transient increases in IRS-2 mRNA concentration in the few hours following a single bout of both endurance and resistance exercise. IRS-2 protein abundance was also observed to significantly increase 24-hours following a single bout of endurance exercise indicating transcriptional regulation of IRS-2 following muscular contraction. One final component of this PhD project was to examine a second novel insulin-signalling pathway via c-Cbl tyrosine phosphorylation that has recently been shown to be essential for insulin stimulated glucose uptake in adipocytes. No evidence was found for the tyrosine phosphorylation of c-Cbl in the skeletal muscle of Zucker rats despite demonstrating significant phosphorylation of the insulin receptor and Akt by insulin treatment and successfully immunoprecipitating c-Cbl protein. Surprisingly, there was a small but significant increase in c-Cbl protein expression following insulin-stimulation, however c-Cbl tyrosine phosphorylation does not appear to be associated with insulin or exercise-mediated glucose transport in skeletal muscle.

The purpose of this study is to investigate the role of strain in the accumulation of crystalline defects created by ion irradiation. Previous studies state that strained Si1xGex is more easily amorphized by ion irradiation than unstrained, bulk Si in a periodic superlattice structure; however, the reason for preferential amorphization of the strained Si1xGex layer in the periodic structure of strained and unstrained layers is not well understood. In this study, various ion irradiations will be carried out on SiGe strained layer superlattices grown on (100)-orientation bulk Si by low temperature molecular beam epitaxy. The samples under investigation are 50 nm surface Si0:8Ge0:2/bulk Si and 50 nm surface Si/60 nm Si0:8Ge0:2/bulk Si. Defects will be created in both surface and buried SiGe strained layers by medium and high energy light ion irradiation. The amount of permanently displaced atoms will be quantified by channeling Rutherford backscattering spectrometry. The amorphization model, the path to permanent damage creation, of bulk Si and surface strained SiGe will be investigated. The strain in surface and buried Si0:8Ge0:2 layers will be measured by comparison to bulk Si with Rutherford backscattering spectrometry by a novel technique, channeling analysis by multi-axial Rutherford backscatter- ing spectrometry, and the limitations of measuring strain by this technique will be explored. Results of this study indicated that the amorphization model, the number of ion collision cascades that must overlap to cause permanent damage, of strained Si0:8Ge0:2 is similar to that of bulk Si, suggesting that point defect recombination is less efficient in strained Si0:8Ge0:2. Additionally, a surface strained Si0:8Ge0:2 is less stable under ion irradiation than buried strained Si0:8Ge0:2. Repeated analysis by multi-axial channeling Rutherford backscattering spectrometry, which requires high fluence of 2 MeV He ions, proved destructive to the surface strained Si0:8Ge0:2 layer.

Low density surface sites are believed to play an important role in processes occurring on oxide surfaces, including catalysis and particle and film nucleation. However, our understanding of the role and chemical nature of such sites play in these processes is limited by the inability to experimentally detect minority surface sites in many oxide systems. The research performed for this dissertation is focused on developing a surface science technique utilizing fluorescent molecules to titrate specific surface sites on planar fused silica surfaces in an ultra-high vacuum (UHV) environment. High sensitivity (low detection limit) is achieved by using derivatives of perylene, a high quantum yield fluorophore. High specificity is attained by employing perylene derivatives with functional groups designed to react chemically with and titrate various sites. In addition to titrating the well-studied hydroxyl sites with perylene-3-methanol (density ~ 10¹⁴ cm⁻²), which is used to establish the technique, the detection of strained siloxane sites (~ 10¹² cm⁻²), ) with perylene-3-methanamine and oxygen vacancy sites (~ 10¹¹ cm⁻²), ) with 3-vinyl perylene is demonstrated. Particle nucleation on oxides is suspected to involve defects that trap adatoms and form critical nuclei. Using this technique, the possible role strained siloxane and oxygen vacancy sites play in trapping adatoms during the nucleation of Ge nanoparticles on silica surfaces is examined. / text

abstract: The goal of this research work is to develop a particle-based device simulator for modeling strained silicon devices. Two separate modules had to be developed for that purpose: A generic bulk Monte Carlo simulation code which in the long-time limit solves the Boltzmann transport equation for electrons; and an extension to this code that solves for the bulk properties of strained silicon. One scattering table is needed for conventional silicon, whereas, because of the strain breaking the symmetry of the system, three scattering tables are needed for modeling strained silicon material. Simulation results for the average drift velocity and the average electron energy are in close agreement with published data. A Monte Carlo device simulation tool has also been employed to integrate the effects of self-heating into device simulation for Silicon on Insulator devices. The effects of different types of materials for buried oxide layers have been studied. Sapphire, Aluminum Nitride (AlN), Silicon dioxide (SiO2) and Diamond have been used as target materials of interest in the analysis and the effects of varying insulator layer thickness have also been investigated. It was observed that although AlN exhibits the best isothermal behavior, diamond is the best choice when thermal effects are accounted for. / Dissertation/Thesis / M.S. Electrical Engineering 2013

The transport properties of zigzag graphene nanoribbons (zGNRs) were studied by density functional theory (DFT) in conjunction with Green’s function analysis. In particular, spin transport through a zGNR (12,0) device was investigated under the constraint of ferromagnetic coordination of the ribbon edges. Several configurations with two vacant sites in the edge and the bulk region of the zGNR device were derived from this system. For all structures, magnetocurrent ratios (MCRs) were recorded as a function of the bias as well as the amount of strain applied longitudinally to the devices. ZGNR devices with vacancies in the edge regime turn out to exhibit perfect spin-filter activity for well-defined choices of the strain and the bias, carrying completely polarized minority spin currents. In the alternative structure, characterized by vacancies in the bulk regime, spin currents with majority orientation prevail. With respect to both the sign and the size, the MCR is seen to depend sensitively on the device parameters, i.e., the vacancy locations, the bias, and the amount of strain. These results are interpreted in terms of density-of-states distributions, transmission spectra, and transmission operator eigenstates.