Solid-State Dynamics in the closo-Carboranes:A (11)B MAS NMR and Molecular Dynamics Study

This work explores the dynamic behaviour of the three closo-carborane isomers (formula C2B10H12) using modern solid-state magic angle spinning (MAS) NMR techniques and relates the experimental measurements to theoretical results obtained using molecular dynamics simulations. At high temperatures and at B0 = 9.4 T, the 11B MAS linewidths are narrow (40-90 Hz) for the three isomers. The rotational correlation times (tauc) calculated by molecular dynamics are on the picosecond timescale, showing a quasi-isotropic rotation at these temperatures, typical for liquid systems. For all three isomers, the values of the 11B spin-lattice relaxation times (T1) show discontinuities as the temperature is decreased, confirming the phase changes reported in the literature. At low temperatures, the 11B MAS spectra of all three isomers exhibit much broader lines. The simulations showed that the molecular reorientation was anisotropic around different symmetry axes for each isomer, and this was supported by the values of the reduced quadrupolar parameter PQeff derived from “dynamic shift” measurements using 11B MQMAS NMR spectroscopy. The behaviour of PQeff as a function of temperature for para-carborane suggests that molecular reorientation is about the C5 symmetry axis of the molecule at low temperatures and this was supported by the molecular dynamics simulations

Identifying suitable land uses and possible conflicts through LUCIS analysis and including localised geological circumstances : JB Marks and City of Matlosana local municipalities, South Africa as case studies

MSc (Urban and Regional Planning), North-West University, Potchefstroom CampusThis research is aimed at identifying land use conflicts in the JB Marks and City of Matlosana municipalities, South Africa, which could be used as a framework for future spatial developments. South African cities are experiencing urbanisation at a rate exceeding the capabilities of cities to properly plan city expansion. This leads to urban sprawl which causes the loss of productive agricultural land and valuable biodiversity. This leads to a problem which will lead to issues such as food security, disasters and inequality. Therefore, the study is designed to help tackle these issues. Further objectives for the study are to identify suitable locations for conservation, urban and agriculture land uses and in turn support biodiversity conservation efforts. Therefore, Land Use Conflict Identification Strategy (LUCIS) is used which can identify possible land use conflicts by calculating land use suitability and comparing these suitability metrics. This information allows decision makers to make effective decisions for land use management and support sustainability. By using a literature review criterion are chosen for urban, conservation and agriculture land use suitability. Questionnaires and literature reviews were then used to create weights for the criteria by using the Analytic Hierarchy Process (AHP) method. The weights were used as inputs for weighted overlay in GIS which created the land use suitability maps. By combining the maps land use conflict could be identified and showed a wide variety of conflicts between all three land uses. Most notably the conflict between agriculture and conservation represented the majority of the conflict followed by agriculture and urban conflicts. Furthermore, a Height Above Nearest Drainage (HAND) model was used to identify possible flood risk, which showed a large extent of Potchefstroom and Klerksdorp’s urban area has high flood. This accomplished the objectives of identifying hazardous areas and highlighting the value of adding flood risk to LUCIS. The LUCIS method can further be developed by looking at higher levels of public participation and a greater variety of variables. The addition of flood risk is a valuable tool to help future decision and therefore more detailed methods of determining flood risk will add value to such research. By using the maps created land use decisions in the study area can mitigate the effect cities have on the environment by allocating land for the best uses.Master