Geomagnetically induced current characteristics in southern Africa
- Authors: Ngwira, Chigomezyo Mudala
- Date: 2009
- Subjects: Magnetic Observatory (South African Council for Scientific and Industrial Research) Geomagnetism -- Africa,Southern Computer networks -- Africa, Southern Magnetospheric currents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5469 , http://hdl.handle.net/10962/d1005254
- Description: Geomagnetically induced currents (GICs), resulting from adverse space weather, have been demonstrated to cause damage to power transformers at mid-latitudes. There is growing concern over possible GIC effects in the Southern African network due to its long power lines. Previous efforts to model the electric field associated with GICs in the Southern Africa region used a uniform ground conductivity model. In an effort to improve the modelling of GICs, GIC data together with Hermanus Magnetic Observatory geomagnetic field data were used to obtain a multilayered ground conductivity model. This process requires a definition of the network coefficients, which are then used in subsequent calculations. This study shows that GIC computed with the new network coefficients and the multilayered ground conductivity model improves the accuracy of GIC modelling. Then GIC statistics are derived based on the recordings of the geomagnetic field at Hermanus, the new network coefficients and ground conductivity model. The geoelectric field is modelled using the plane wave method. The properties of the geomagnetic field, their time derivatives and local geomagnetic indices were investigated to determine their characteristics in relation to the GIC. The pattern of the time derivatives of the horizontal geomagnetic field closely follow the rate of change of the north-south geomagnetic component rather than the east-west component. The correlation between the GIC and the local geomagnetic field indices was also investigated. The results show that there is a higher correlation between the GIC and the east-west components of the geomagnetic local indices than between the GIC and the north-south components. This corresponds very well with the orientation of the power lines feeding the power transformers at the South African Grassridge electrical substation GIC site. Thus, the geoelectric field driving the GIC at Grassridge is north-south oriented. Further, it is shown that the geomagnetic observation sites have a strong directional preference with respect to the Grassridge GIC site.
- Full Text:
- Date Issued: 2009
- Authors: Ngwira, Chigomezyo Mudala
- Date: 2009
- Subjects: Magnetic Observatory (South African Council for Scientific and Industrial Research) Geomagnetism -- Africa,Southern Computer networks -- Africa, Southern Magnetospheric currents
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5469 , http://hdl.handle.net/10962/d1005254
- Description: Geomagnetically induced currents (GICs), resulting from adverse space weather, have been demonstrated to cause damage to power transformers at mid-latitudes. There is growing concern over possible GIC effects in the Southern African network due to its long power lines. Previous efforts to model the electric field associated with GICs in the Southern Africa region used a uniform ground conductivity model. In an effort to improve the modelling of GICs, GIC data together with Hermanus Magnetic Observatory geomagnetic field data were used to obtain a multilayered ground conductivity model. This process requires a definition of the network coefficients, which are then used in subsequent calculations. This study shows that GIC computed with the new network coefficients and the multilayered ground conductivity model improves the accuracy of GIC modelling. Then GIC statistics are derived based on the recordings of the geomagnetic field at Hermanus, the new network coefficients and ground conductivity model. The geoelectric field is modelled using the plane wave method. The properties of the geomagnetic field, their time derivatives and local geomagnetic indices were investigated to determine their characteristics in relation to the GIC. The pattern of the time derivatives of the horizontal geomagnetic field closely follow the rate of change of the north-south geomagnetic component rather than the east-west component. The correlation between the GIC and the local geomagnetic field indices was also investigated. The results show that there is a higher correlation between the GIC and the east-west components of the geomagnetic local indices than between the GIC and the north-south components. This corresponds very well with the orientation of the power lines feeding the power transformers at the South African Grassridge electrical substation GIC site. Thus, the geoelectric field driving the GIC at Grassridge is north-south oriented. Further, it is shown that the geomagnetic observation sites have a strong directional preference with respect to the Grassridge GIC site.
- Full Text:
- Date Issued: 2009
The development of the stock market and its effect on economic growth: the case of SADC
- Authors: Elliott, Kevin Andrew
- Date: 2009
- Subjects: Stocks -- Africa, Southern , Stock exchanges -- Africa, Southern , Economic development -- Africa, Southern , Stocks -- Economic aspects -- Africa, Southern
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:967 , http://hdl.handle.net/10962/d1002701 , Stocks -- Africa, Southern , Stock exchanges -- Africa, Southern , Economic development -- Africa, Southern , Stocks -- Economic aspects -- Africa, Southern
- Description: Using a pooled panel data set from nine developing countries within the SADC region from 1992 to 2004, this paper empirically examines; firstly, the relationship between stock market development and long-term economic growth, and secondly, the macroeconomic determinants of stock market development, particularly market capitalisation as a percentage of GDP. The results suggest that there is a strong link between stock market development and economic growth, particularly through the liquidity provided by the market. The evidence obtained lends support to the view that a well-developed and functioning stock market can boost economic growth by enhancing faster capital accumulation and allowing for better resource allocation, particularly in developing countries. In terms of the macroeconomic determinants of stock market development, the results support those of Garcia and Liu (1999), in that we found the indicators of financial intermediary development, the value of shares traded as a percentage of GDP and the macroeconomic instability variable to be important determinants of stock market development.
- Full Text:
- Date Issued: 2009
- Authors: Elliott, Kevin Andrew
- Date: 2009
- Subjects: Stocks -- Africa, Southern , Stock exchanges -- Africa, Southern , Economic development -- Africa, Southern , Stocks -- Economic aspects -- Africa, Southern
- Language: English
- Type: Thesis , Masters , MCom
- Identifier: vital:967 , http://hdl.handle.net/10962/d1002701 , Stocks -- Africa, Southern , Stock exchanges -- Africa, Southern , Economic development -- Africa, Southern , Stocks -- Economic aspects -- Africa, Southern
- Description: Using a pooled panel data set from nine developing countries within the SADC region from 1992 to 2004, this paper empirically examines; firstly, the relationship between stock market development and long-term economic growth, and secondly, the macroeconomic determinants of stock market development, particularly market capitalisation as a percentage of GDP. The results suggest that there is a strong link between stock market development and economic growth, particularly through the liquidity provided by the market. The evidence obtained lends support to the view that a well-developed and functioning stock market can boost economic growth by enhancing faster capital accumulation and allowing for better resource allocation, particularly in developing countries. In terms of the macroeconomic determinants of stock market development, the results support those of Garcia and Liu (1999), in that we found the indicators of financial intermediary development, the value of shares traded as a percentage of GDP and the macroeconomic instability variable to be important determinants of stock market development.
- Full Text:
- Date Issued: 2009
An investigation of how members of a school board perceive and experience their roles in a secondary school in the Rundu Education Region of Namibia
- Authors: Kasokonya, Sinvula Martin
- Date: 2007
- Subjects: School boards -- Namibia School management and organization -- Namibia Educational leadership School personnel management Education -- Political aspects -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1861 , http://hdl.handle.net/10962/d1004558
- Description: The purpose of this study was to investigate School Board members' perceptions and expenences of their roles in a secondary school in the Rundu Education Region of Namibia. A case study was conducted within the interpretive paradigm. Six School Board members from the selected school were interviewed. The data were analysed using qualitative data analysis practices. The findings of the study indicate that there are numerous constraints that interfere with the Board members' ability to effectively carry out their role as a school governing body. These constraints include a lack of knowledge and understanding of the Education Act, a lack of skill in conducting basic management and organization processes and a lack of support from the circuit inspector and Regional Education officers. This study provides some understanding of the circumstances of the School Board in trying to execute its role in implementing the Education Act, especially the section dealing with School Boards. As such, this research provides an agenda for the support and improvement of the work of School Boards in Namibian secondary schools.
- Full Text:
- Date Issued: 2007
- Authors: Kasokonya, Sinvula Martin
- Date: 2007
- Subjects: School boards -- Namibia School management and organization -- Namibia Educational leadership School personnel management Education -- Political aspects -- Namibia
- Language: English
- Type: Thesis , Masters , MEd
- Identifier: vital:1861 , http://hdl.handle.net/10962/d1004558
- Description: The purpose of this study was to investigate School Board members' perceptions and expenences of their roles in a secondary school in the Rundu Education Region of Namibia. A case study was conducted within the interpretive paradigm. Six School Board members from the selected school were interviewed. The data were analysed using qualitative data analysis practices. The findings of the study indicate that there are numerous constraints that interfere with the Board members' ability to effectively carry out their role as a school governing body. These constraints include a lack of knowledge and understanding of the Education Act, a lack of skill in conducting basic management and organization processes and a lack of support from the circuit inspector and Regional Education officers. This study provides some understanding of the circumstances of the School Board in trying to execute its role in implementing the Education Act, especially the section dealing with School Boards. As such, this research provides an agenda for the support and improvement of the work of School Boards in Namibian secondary schools.
- Full Text:
- Date Issued: 2007
A re-examination of the Carter solutions of Einstein's field equations
- Authors: Kun, A Ah
- Date: 1979
- Subjects: Einstein field equations Space and time General relativity (Physics)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5442 , http://hdl.handle.net/10962/d1001995
- Description: The study of geodesics in space-time is essential to a comprehensive understanding of the physics of the field. Global properties, e.g. the singularity structure and completeness of space-time, can be related to the geodesic properties, thus it is through the solutions of the geodesic equation of motion that many of the global properties of space-time can be obtained in an easily interpretable form. However, it is usually very difficult to integrate the geodesic equations for the particle motion in the presence of a gravitational field (Introduction, p. 1)
- Full Text:
- Date Issued: 1979
- Authors: Kun, A Ah
- Date: 1979
- Subjects: Einstein field equations Space and time General relativity (Physics)
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:5442 , http://hdl.handle.net/10962/d1001995
- Description: The study of geodesics in space-time is essential to a comprehensive understanding of the physics of the field. Global properties, e.g. the singularity structure and completeness of space-time, can be related to the geodesic properties, thus it is through the solutions of the geodesic equation of motion that many of the global properties of space-time can be obtained in an easily interpretable form. However, it is usually very difficult to integrate the geodesic equations for the particle motion in the presence of a gravitational field (Introduction, p. 1)
- Full Text:
- Date Issued: 1979