Laser surface hardening of AISI 1518 alloy steel
- Authors: Zhang, Tao
- Date: 2010
- Subjects: Lasers , Laser beams , Lasers in engineering , Nd-YAG lasers , Steel alloys , Surfaces -- Effect of radiation on
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9613 , http://hdl.handle.net/10948/723 , Lasers , Laser beams , Lasers in engineering , Nd-YAG lasers , Steel alloys , Surfaces -- Effect of radiation on
- Description: The laser surface hardening process will enhance the hardness profile of automotive components and ensure better process control and predictability of quality as compared to the conventional hardening processes. A 2KW Nd-YAG laser system was used to harden the surface of alloy steel with various process parameters (laser power, focal spot diameter and beam velocity). The results (microhardness, microstructure change and residual stress distribution) were measured and analyzed with Vickers microhardness tester, optical/electron microscope and hole-drilling residual stress equipment. Statistical analyses of the experimental data were used for explaining the relationships between process parameters, microhardness and microstructure. General thermal hardening was applied in the research to show the influence of heating temperature and cooling method on microstructure and mechanical properties. Also, the results were compared with laser surface hardening process from microhardness, microstructure and residual stress to show the advantage of laser surface hardening. Through analysis of the results of the laser surface hardening experiments, a suitable laser power density and interaction time for optimum hardening was obtained. The presented laser surface hardening process can also be applied to other alloy steel surface hardening process.
- Full Text:
- Date Issued: 2010
- Authors: Zhang, Tao
- Date: 2010
- Subjects: Lasers , Laser beams , Lasers in engineering , Nd-YAG lasers , Steel alloys , Surfaces -- Effect of radiation on
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9613 , http://hdl.handle.net/10948/723 , Lasers , Laser beams , Lasers in engineering , Nd-YAG lasers , Steel alloys , Surfaces -- Effect of radiation on
- Description: The laser surface hardening process will enhance the hardness profile of automotive components and ensure better process control and predictability of quality as compared to the conventional hardening processes. A 2KW Nd-YAG laser system was used to harden the surface of alloy steel with various process parameters (laser power, focal spot diameter and beam velocity). The results (microhardness, microstructure change and residual stress distribution) were measured and analyzed with Vickers microhardness tester, optical/electron microscope and hole-drilling residual stress equipment. Statistical analyses of the experimental data were used for explaining the relationships between process parameters, microhardness and microstructure. General thermal hardening was applied in the research to show the influence of heating temperature and cooling method on microstructure and mechanical properties. Also, the results were compared with laser surface hardening process from microhardness, microstructure and residual stress to show the advantage of laser surface hardening. Through analysis of the results of the laser surface hardening experiments, a suitable laser power density and interaction time for optimum hardening was obtained. The presented laser surface hardening process can also be applied to other alloy steel surface hardening process.
- Full Text:
- Date Issued: 2010
Modeling of arsenic removal from aqueous media using selected coagulants
- Authors: Majavu, Avela
- Date: 2010
- Subjects: Arsenic wastes , Water -- Purification -- Arsenic removal , Coagulation
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10426 , http://hdl.handle.net/10948/d1017100
- Description: The waste water from the industrial production of the herbicide monosodium methyl arsenate was treated using coagulation. The coagulation process as developed in this research proved to be suitable for arsenic removal in aqueous media using chromium (III), calcium (II), and combination of calcium (II) and chromium (III), and magnesium (II). The results obtained suggest that the coagulation process can be used for the treatment of the waste water from the monosodium methyl arsenate production. Response surface methodology was used to study the effects of the various parameters, namely pH, mole ratios (Cr:As, Ca:As, and Mg:As), concentration of flocculent and initial arsenic concentration. To optimize the process conditions for the maximum removal of arsenic. Central composite and factorial designs were used to study the effects of these variables and to predict the effect of each. ANOVA was used to identify those factors which had significant effects on model quality and performance. The initial arsenic concentration appeared to be the only significant factor. These models were statistically tested and verified by confirmation experiments.
- Full Text:
- Date Issued: 2010
- Authors: Majavu, Avela
- Date: 2010
- Subjects: Arsenic wastes , Water -- Purification -- Arsenic removal , Coagulation
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10426 , http://hdl.handle.net/10948/d1017100
- Description: The waste water from the industrial production of the herbicide monosodium methyl arsenate was treated using coagulation. The coagulation process as developed in this research proved to be suitable for arsenic removal in aqueous media using chromium (III), calcium (II), and combination of calcium (II) and chromium (III), and magnesium (II). The results obtained suggest that the coagulation process can be used for the treatment of the waste water from the monosodium methyl arsenate production. Response surface methodology was used to study the effects of the various parameters, namely pH, mole ratios (Cr:As, Ca:As, and Mg:As), concentration of flocculent and initial arsenic concentration. To optimize the process conditions for the maximum removal of arsenic. Central composite and factorial designs were used to study the effects of these variables and to predict the effect of each. ANOVA was used to identify those factors which had significant effects on model quality and performance. The initial arsenic concentration appeared to be the only significant factor. These models were statistically tested and verified by confirmation experiments.
- Full Text:
- Date Issued: 2010
Navigating between information security management documents : a modeling methodology
- Authors: Domingues, Steve
- Date: 2010
- Subjects: Computer security -- Management , Business -- Data processing -- Security measures , Information resources management -- Security measures , Business -- Standards
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9761 , http://hdl.handle.net/10948/1212 , Computer security -- Management , Business -- Data processing -- Security measures , Information resources management -- Security measures , Business -- Standards
- Description: Organizations no longer draft their own standards. Instead, organizations take advantage of the available international standards. One standard may not cover all the organization's needs, requiring organizations to implement more than one standard. The same aspect in an organization may be covered by two or more standards, creating an overlap. An awareness of such overlaps led to various institutions creating mapping documents illustrating how a control from one standard relates to a control from a different standard. The mapping documents are consulted by the end user, to identify how a control in one standard may relate to other standards. This allows the end user to navigate between the standards documents. These mapping documents are valuable to a person who wishes to grasp how different standards deal with a specific control. However, the navigation between standards is a cumbersome task. In order to navigate between the standards the end user is required to consult three or more documents, depending on the number of standards that are mapped to the control being investigated. The need for a tool that will provide fast and efficient navigation between standards was identified. The data tier of the tool is the focus of this dissertation. As a result, this research proposes a modeling methodology that will allow for the modeling of the standards and the information about the mapping between standards, thereby contributing to the creation of tools to aid in the navigation between standards. A comparison between the major data modeling paradigms identifies multi-dimensional modeling as the most appropriate technique to model standards. Adapting an existing modeling methodology to cater for the modeling standards, yield a five step standard modeling methodology. Once modeled, the standards can be physically implemented as a database. The database schema that results from the standard modeling methodology adheres to a specific pattern and can thus be expressed according to well-defined meta-model. This allows for the generation of SQL statements by a tool with limited knowledge of the standards in a way that allows the quick navigation between standards. To determine the usefulness of the standards modeling methodology the research presents iv a prototype that utilizes the well-defined meta-model to navigate between standards. It is shown that, as far as navigation is concerned, no code changes are necessary when adding a new standard or new mappings between standards. This research contributes to the creation of a tool that can easily navigate between standards by providing the ability to model the data tier in such a way that it is extensible, yet remains independent of the application and presentation tiers.
- Full Text:
- Date Issued: 2010
- Authors: Domingues, Steve
- Date: 2010
- Subjects: Computer security -- Management , Business -- Data processing -- Security measures , Information resources management -- Security measures , Business -- Standards
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9761 , http://hdl.handle.net/10948/1212 , Computer security -- Management , Business -- Data processing -- Security measures , Information resources management -- Security measures , Business -- Standards
- Description: Organizations no longer draft their own standards. Instead, organizations take advantage of the available international standards. One standard may not cover all the organization's needs, requiring organizations to implement more than one standard. The same aspect in an organization may be covered by two or more standards, creating an overlap. An awareness of such overlaps led to various institutions creating mapping documents illustrating how a control from one standard relates to a control from a different standard. The mapping documents are consulted by the end user, to identify how a control in one standard may relate to other standards. This allows the end user to navigate between the standards documents. These mapping documents are valuable to a person who wishes to grasp how different standards deal with a specific control. However, the navigation between standards is a cumbersome task. In order to navigate between the standards the end user is required to consult three or more documents, depending on the number of standards that are mapped to the control being investigated. The need for a tool that will provide fast and efficient navigation between standards was identified. The data tier of the tool is the focus of this dissertation. As a result, this research proposes a modeling methodology that will allow for the modeling of the standards and the information about the mapping between standards, thereby contributing to the creation of tools to aid in the navigation between standards. A comparison between the major data modeling paradigms identifies multi-dimensional modeling as the most appropriate technique to model standards. Adapting an existing modeling methodology to cater for the modeling standards, yield a five step standard modeling methodology. Once modeled, the standards can be physically implemented as a database. The database schema that results from the standard modeling methodology adheres to a specific pattern and can thus be expressed according to well-defined meta-model. This allows for the generation of SQL statements by a tool with limited knowledge of the standards in a way that allows the quick navigation between standards. To determine the usefulness of the standards modeling methodology the research presents iv a prototype that utilizes the well-defined meta-model to navigate between standards. It is shown that, as far as navigation is concerned, no code changes are necessary when adding a new standard or new mappings between standards. This research contributes to the creation of a tool that can easily navigate between standards by providing the ability to model the data tier in such a way that it is extensible, yet remains independent of the application and presentation tiers.
- Full Text:
- Date Issued: 2010
Process window for friction stir welding of 3 mm titanium (Ti-6AI-4V)
- Authors: Mashinini, Peter Madindwa
- Date: 2010
- Subjects: Friction stir welding , Titanium -- Welding , Welded joints
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9618 , http://hdl.handle.net/10948/1413 , Friction stir welding , Titanium -- Welding , Welded joints
- Description: Friction stir welding was used to join 3 mm Ti-6Al-4V alloy in a butt joint configuration. This research focused on optimization of a tool geometry and the interaction between process parameters and static performance of welded joints. The main parameters varied were tool travel speed and tool rotational speed. The results showed a relationship between heat input as a function of process parameters and static strength. Improved tensile properties correspond to high heat input. The hardness plots revealed an increase in hardness on both the stir zone and heat affected zone despite the small defects on the weld root. The weld microstructure was also evaluated, which showed a variation in microstructure on both the heat affected zone and stir zone in comparison to the parent material. It was also found that the use of MgO as a heat barrier on the backing plate was detrimental to the weld tensile properties of butt-welded plates compared to bead-on-plate welds of which MgO had no influence.
- Full Text:
- Date Issued: 2010
- Authors: Mashinini, Peter Madindwa
- Date: 2010
- Subjects: Friction stir welding , Titanium -- Welding , Welded joints
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9618 , http://hdl.handle.net/10948/1413 , Friction stir welding , Titanium -- Welding , Welded joints
- Description: Friction stir welding was used to join 3 mm Ti-6Al-4V alloy in a butt joint configuration. This research focused on optimization of a tool geometry and the interaction between process parameters and static performance of welded joints. The main parameters varied were tool travel speed and tool rotational speed. The results showed a relationship between heat input as a function of process parameters and static strength. Improved tensile properties correspond to high heat input. The hardness plots revealed an increase in hardness on both the stir zone and heat affected zone despite the small defects on the weld root. The weld microstructure was also evaluated, which showed a variation in microstructure on both the heat affected zone and stir zone in comparison to the parent material. It was also found that the use of MgO as a heat barrier on the backing plate was detrimental to the weld tensile properties of butt-welded plates compared to bead-on-plate welds of which MgO had no influence.
- Full Text:
- Date Issued: 2010
The fatigue life cycle prediction of a light aircraft undercarriage
- Authors: Erasmus, Daniel Jacobus
- Date: 2010
- Subjects: Metals--Fatigue
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9614 , http://hdl.handle.net/10948/1527 , Metals--Fatigue
- Description: The reliability of systems relies heavily on accurate fatigue life prediction of related components. Fatigue life prediction is a complicated process requiring the correct methodology to determine accurate and reliable predictions. The Palmgren – Miner damage accumulation hypothesis is widely used in determining the fatigue life of components exposed to variable loading conditions. Modifications have been made to this hypothesis trying to achieve a greater degree of accuracy, of these the Liu – Zenner modification has been the most successful. In this report the systematic process of fatigue life prediction using the Liu – Zenner modification to achieve reliable results is calculated. A representative stress time history measured in service on the component forms the basis for defining a flight cycle which is the chosen unit in which to express the fatigue life. Rainflow cycle counting performed on the stress time history allowed the formulation of a load spectrum to which the component is exposed in one cycle. Combining the load spectrum with the developed SN curve of the component and using the Liu – Zenner modification to the Palmgren – Miner rule a reliable fatigue life in cycles is predicted.
- Full Text:
- Date Issued: 2010
- Authors: Erasmus, Daniel Jacobus
- Date: 2010
- Subjects: Metals--Fatigue
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9614 , http://hdl.handle.net/10948/1527 , Metals--Fatigue
- Description: The reliability of systems relies heavily on accurate fatigue life prediction of related components. Fatigue life prediction is a complicated process requiring the correct methodology to determine accurate and reliable predictions. The Palmgren – Miner damage accumulation hypothesis is widely used in determining the fatigue life of components exposed to variable loading conditions. Modifications have been made to this hypothesis trying to achieve a greater degree of accuracy, of these the Liu – Zenner modification has been the most successful. In this report the systematic process of fatigue life prediction using the Liu – Zenner modification to achieve reliable results is calculated. A representative stress time history measured in service on the component forms the basis for defining a flight cycle which is the chosen unit in which to express the fatigue life. Rainflow cycle counting performed on the stress time history allowed the formulation of a load spectrum to which the component is exposed in one cycle. Combining the load spectrum with the developed SN curve of the component and using the Liu – Zenner modification to the Palmgren – Miner rule a reliable fatigue life in cycles is predicted.
- Full Text:
- Date Issued: 2010
The investigation of alternative processes for the oxidation of phenol
- Authors: Pongoma, Basanda
- Date: 2010
- Subjects: Phenol , Hydroquinone
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10381 , http://hdl.handle.net/10948/1479 , Phenol , Hydroquinone
- Description: The electrochemical oxidation of phenol can be considered as an important process for either producing value added products such as hydroquinone and catechol or for the removal of the phenol from waste water streams to form carbon dioxide. This process had been extensively studied with the main focus on type of anode material used. Even though the anode material could be made from a range of materials, this study focused on using PbO2 as anode material that was made by using Pb-acid battery principles in designing a microporous electrode. In this study, the focus was on using lead dioxide as an anode material that was made by using the formation principles used in the manufacturing of Pb-acid batteries. This allowed for the construction of an electrochemical flow-through micro-porous reactor that contained PbO2 as the anode and Pb as the cathode, allowing for a solution containing phenol to flow through the cell continuously. By applying a suitable potential across the cell, the almost complete oxidation of phenol would occur to form benzoquinone, which was followed by the sequential reduction to other products such as hydroquinone and catechol. The system was shown to be made up of tightly packed micro-porous material that had a very high surface area-to-volume ratio. The study showed that between 80 to 90 percent successful conversion of a 50 mM solution of phenol could be achieved by optimizing the continuous flow process of up to 500 minutes. The main reaction product from this process was hydroquinone, of up to 60 percent with a number of the minor products of which not all could be identified. In order to utilize the characteristics of this reactor system, its design and reaction conditions such as applied potential, phenol concentration, co-solvent concentration and support electrolyte concentration were investigated to optimize the convection of phenol and the yield of hydroquinone.
- Full Text:
- Date Issued: 2010
- Authors: Pongoma, Basanda
- Date: 2010
- Subjects: Phenol , Hydroquinone
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10381 , http://hdl.handle.net/10948/1479 , Phenol , Hydroquinone
- Description: The electrochemical oxidation of phenol can be considered as an important process for either producing value added products such as hydroquinone and catechol or for the removal of the phenol from waste water streams to form carbon dioxide. This process had been extensively studied with the main focus on type of anode material used. Even though the anode material could be made from a range of materials, this study focused on using PbO2 as anode material that was made by using Pb-acid battery principles in designing a microporous electrode. In this study, the focus was on using lead dioxide as an anode material that was made by using the formation principles used in the manufacturing of Pb-acid batteries. This allowed for the construction of an electrochemical flow-through micro-porous reactor that contained PbO2 as the anode and Pb as the cathode, allowing for a solution containing phenol to flow through the cell continuously. By applying a suitable potential across the cell, the almost complete oxidation of phenol would occur to form benzoquinone, which was followed by the sequential reduction to other products such as hydroquinone and catechol. The system was shown to be made up of tightly packed micro-porous material that had a very high surface area-to-volume ratio. The study showed that between 80 to 90 percent successful conversion of a 50 mM solution of phenol could be achieved by optimizing the continuous flow process of up to 500 minutes. The main reaction product from this process was hydroquinone, of up to 60 percent with a number of the minor products of which not all could be identified. In order to utilize the characteristics of this reactor system, its design and reaction conditions such as applied potential, phenol concentration, co-solvent concentration and support electrolyte concentration were investigated to optimize the convection of phenol and the yield of hydroquinone.
- Full Text:
- Date Issued: 2010
The management of extralimital giraffe (Giraffa Camelopardalis) in the mosaic thicket of Southern Cape, South Africa
- Authors: Cornelius, Andri Judith
- Date: 2010
- Subjects: Giraffe -- South Africa -- Eastern Cape , Giraffe -- Food -- South Africa -- Eastern Cape , Giraffe -- Ecology -- South Africa -- Eastern Cape , Animal behavior , Animal-plant relationships -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10749 , http://hdl.handle.net/10948/1345 , Giraffe -- South Africa -- Eastern Cape , Giraffe -- Food -- South Africa -- Eastern Cape , Giraffe -- Ecology -- South Africa -- Eastern Cape , Animal behavior , Animal-plant relationships -- South Africa -- Eastern Cape
- Description: The giraffe at Nyaru were found to be browsers who made little use of graze during the study period. They utilized a diversity of 20 browse species. Two species, Acacia karroo and Acacia cyclops, formed the bulk of the giraffe diet throughout the year. A definite seasonal dietary shift was evident. A. karroo was favoured in summer and autumn and formed the main food species in spring, summer and autumn. A. cyclops was favoured throughout the study, but its contribution to the diet increased during winter when less A. karroo was consumed. This seasonal shift is related to the deciduous nature of Acacia karroo. Although a seasonal shift in species contribution to giraffe diet has been observed in many other giraffe feeding studies, no studies on giraffe feeding have been done in the Mosaic Thicket of the southern Cape. The ecological browsing capacity for giraffe in thicket was estimated to be between 0.020 BU/ha and 0.095 BU/ha. The browsing capacity for giraffe at Nyaru, based on the available phytomass 2–5 m above the ground, was estimated using those species that formed the bulk of the giraffe diet, and amounted to 0.063 BU/ha. A maximum of three giraffe could thus be stocked on the 157 ha of suitable giraffe habitat on Nyaru. This stocking rate recommendation lies within the range commonly recommended by local consultants for giraffe introductions into the southern Cape. Their recommendations are, however, not based on quantitative assessments such as performed in this study. The recommendation of this study should not be applied as a fixed ecological capacity for giraffe in thicket, but should be seen as a starting point in the adaptive management cycle. Ongoing monitoring of parameters, such as herbaceous composition and phytomass; as well as the condition of key browse species, is strongly advocated. A. karroo was browsed significantly more and carried significantly fewer pods per tree at a heavily used site compared to a lightly used site. Heavy browsing thus appears to affect the reproductive success of A. karroo significantly. Fewer pods are likely to lead to lower regeneration and thus reduced density of A. karroo. Whether A. karroo will maintain its dominance within the thicket vii community in the long run will be related to how individual plants survive and reproduce and if some can escape from herbivory. Fewer G. occidentalis were clumped with other species at the heavily used site compared to the lightly used site. This could possibly be attributed to the fact that intense browsing pressure at the heavily used site caused protective clumps to be eaten away, thus exposing G. occidentalis to higher ungulate browsing. Previous studies have found that nurse shrubs protect G. occidentalis against ungulate browsing. G. occidentalis was browsed significantly more at the heavily used site compared to the lightly used site. There was a general trend of fewer fruits at the heavily used site compared to the lightly used site, while fruits were absent on G. occidentalis growing alone at the heavily used site. This suggests a negative effect of heavy browsing on plant reproductive success and emphasizes the importance of nurse plants for the successful recruitment and hence long term prevalence of G. occidentalis in Mosaic Thicket.
- Full Text:
- Date Issued: 2010
- Authors: Cornelius, Andri Judith
- Date: 2010
- Subjects: Giraffe -- South Africa -- Eastern Cape , Giraffe -- Food -- South Africa -- Eastern Cape , Giraffe -- Ecology -- South Africa -- Eastern Cape , Animal behavior , Animal-plant relationships -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10749 , http://hdl.handle.net/10948/1345 , Giraffe -- South Africa -- Eastern Cape , Giraffe -- Food -- South Africa -- Eastern Cape , Giraffe -- Ecology -- South Africa -- Eastern Cape , Animal behavior , Animal-plant relationships -- South Africa -- Eastern Cape
- Description: The giraffe at Nyaru were found to be browsers who made little use of graze during the study period. They utilized a diversity of 20 browse species. Two species, Acacia karroo and Acacia cyclops, formed the bulk of the giraffe diet throughout the year. A definite seasonal dietary shift was evident. A. karroo was favoured in summer and autumn and formed the main food species in spring, summer and autumn. A. cyclops was favoured throughout the study, but its contribution to the diet increased during winter when less A. karroo was consumed. This seasonal shift is related to the deciduous nature of Acacia karroo. Although a seasonal shift in species contribution to giraffe diet has been observed in many other giraffe feeding studies, no studies on giraffe feeding have been done in the Mosaic Thicket of the southern Cape. The ecological browsing capacity for giraffe in thicket was estimated to be between 0.020 BU/ha and 0.095 BU/ha. The browsing capacity for giraffe at Nyaru, based on the available phytomass 2–5 m above the ground, was estimated using those species that formed the bulk of the giraffe diet, and amounted to 0.063 BU/ha. A maximum of three giraffe could thus be stocked on the 157 ha of suitable giraffe habitat on Nyaru. This stocking rate recommendation lies within the range commonly recommended by local consultants for giraffe introductions into the southern Cape. Their recommendations are, however, not based on quantitative assessments such as performed in this study. The recommendation of this study should not be applied as a fixed ecological capacity for giraffe in thicket, but should be seen as a starting point in the adaptive management cycle. Ongoing monitoring of parameters, such as herbaceous composition and phytomass; as well as the condition of key browse species, is strongly advocated. A. karroo was browsed significantly more and carried significantly fewer pods per tree at a heavily used site compared to a lightly used site. Heavy browsing thus appears to affect the reproductive success of A. karroo significantly. Fewer pods are likely to lead to lower regeneration and thus reduced density of A. karroo. Whether A. karroo will maintain its dominance within the thicket vii community in the long run will be related to how individual plants survive and reproduce and if some can escape from herbivory. Fewer G. occidentalis were clumped with other species at the heavily used site compared to the lightly used site. This could possibly be attributed to the fact that intense browsing pressure at the heavily used site caused protective clumps to be eaten away, thus exposing G. occidentalis to higher ungulate browsing. Previous studies have found that nurse shrubs protect G. occidentalis against ungulate browsing. G. occidentalis was browsed significantly more at the heavily used site compared to the lightly used site. There was a general trend of fewer fruits at the heavily used site compared to the lightly used site, while fruits were absent on G. occidentalis growing alone at the heavily used site. This suggests a negative effect of heavy browsing on plant reproductive success and emphasizes the importance of nurse plants for the successful recruitment and hence long term prevalence of G. occidentalis in Mosaic Thicket.
- Full Text:
- Date Issued: 2010
The possibility of a flexible wireless 3-D measurement in the modern automobile production
- Authors: Frede, Stefan
- Date: 2010
- Subjects: Three-dimensional display systems , Automobile industry and trade , Automobile industry and trade -- South Africa -- Quality control
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9619 , http://hdl.handle.net/10948/1203 , Three-dimensional display systems , Automobile industry and trade , Automobile industry and trade -- South Africa -- Quality control
- Description: The quality control of geometrical coherences and relations in modern automobile production is done by different stationary and flexible measurement systems and strategies. Furthermore, there currently exists possibilities of inline measurements and offline measurements. This project presents the basic research concerning the possibility of a flexible wireless measurement system in modern automobile production, that is able to combine the advantages of both strategies. An investigation of existing measurement techniques was done in order to find a sensor technology, which enables the wireless measurement process. The research project introduces the current location systems and positioning systems. These techniques are compared by a value benefit analysis to expose a suited technology as basis for the measurement system. As result of the value benefit anlysis, the ultrasonic technique was selected for further investigations. The ultrasonic test setup is used to analyze the accuracy of modern sensors and to verify the possibility of a project related integration. The tests are done in different conditions, in order to compare the laboratory application and the industrial application. During the test measurements different physical influencing variables and disturbances occurred. From this research project, it can be concluded that the laboratory application of the system is possible. However, the industrial application is subject to restrictions.
- Full Text:
- Date Issued: 2010
- Authors: Frede, Stefan
- Date: 2010
- Subjects: Three-dimensional display systems , Automobile industry and trade , Automobile industry and trade -- South Africa -- Quality control
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9619 , http://hdl.handle.net/10948/1203 , Three-dimensional display systems , Automobile industry and trade , Automobile industry and trade -- South Africa -- Quality control
- Description: The quality control of geometrical coherences and relations in modern automobile production is done by different stationary and flexible measurement systems and strategies. Furthermore, there currently exists possibilities of inline measurements and offline measurements. This project presents the basic research concerning the possibility of a flexible wireless measurement system in modern automobile production, that is able to combine the advantages of both strategies. An investigation of existing measurement techniques was done in order to find a sensor technology, which enables the wireless measurement process. The research project introduces the current location systems and positioning systems. These techniques are compared by a value benefit analysis to expose a suited technology as basis for the measurement system. As result of the value benefit anlysis, the ultrasonic technique was selected for further investigations. The ultrasonic test setup is used to analyze the accuracy of modern sensors and to verify the possibility of a project related integration. The tests are done in different conditions, in order to compare the laboratory application and the industrial application. During the test measurements different physical influencing variables and disturbances occurred. From this research project, it can be concluded that the laboratory application of the system is possible. However, the industrial application is subject to restrictions.
- Full Text:
- Date Issued: 2010
Veldram performance testing of dorper rams in Namibia : performance testing, progency testing and factors influencing sale price of rams
- Grobler, Hermanus Johannes Fourie
- Authors: Grobler, Hermanus Johannes Fourie
- Date: 2010
- Subjects: Dorper sheep -- Breeding -- Namibia , Sheep -- Breeding -- Namibia , Dorper sheep , Sheep breeds
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10733 , http://hdl.handle.net/10948/1545 , Dorper sheep -- Breeding -- Namibia , Sheep -- Breeding -- Namibia , Dorper sheep , Sheep breeds
- Description: The study aims to determine the contribution made by available ram growth- and breed standard parameters on the sale price of auctioned rams in Namibia. These findings serve as an indication of the importance ram buyers place on individual parameters in selecting rams for breeding purposes. It furthermore tries to establish whether scientific measurement for the estimation of ram breeding values takes precedence over subjective appraisal. The analysis of the 100 day and 270 day growth performance of the progeny of selected Veldram tested rams were used to evaluate the accuracy of the estimation of ram breeding values and may serve to validate the proper execution of these Veldram tests.
- Full Text:
- Date Issued: 2010
- Authors: Grobler, Hermanus Johannes Fourie
- Date: 2010
- Subjects: Dorper sheep -- Breeding -- Namibia , Sheep -- Breeding -- Namibia , Dorper sheep , Sheep breeds
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10733 , http://hdl.handle.net/10948/1545 , Dorper sheep -- Breeding -- Namibia , Sheep -- Breeding -- Namibia , Dorper sheep , Sheep breeds
- Description: The study aims to determine the contribution made by available ram growth- and breed standard parameters on the sale price of auctioned rams in Namibia. These findings serve as an indication of the importance ram buyers place on individual parameters in selecting rams for breeding purposes. It furthermore tries to establish whether scientific measurement for the estimation of ram breeding values takes precedence over subjective appraisal. The analysis of the 100 day and 270 day growth performance of the progeny of selected Veldram tested rams were used to evaluate the accuracy of the estimation of ram breeding values and may serve to validate the proper execution of these Veldram tests.
- Full Text:
- Date Issued: 2010
A framework for IT governance in small businesses
- Authors: Koornhof, Herman
- Date: 2009
- Subjects: Corporate governance -- South Africa , Organizational effectiveness -- South Africa , Organisational Management
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9768 , http://hdl.handle.net/10948/994 , Corporate governance -- South Africa , Organizational effectiveness -- South Africa , Organisational Management
- Description: The primary objective of this treatise is to develop a framework that small businesses can use to implement IT governance. This framework for IT 6 Governance in Small Businesses, called ITGovSB, will be based primarily on the CobiT framework and the ISO/IEC 27002 information security controls. In order to achieve the primary objective, it is necessary to understand the differences between IT governance in small businesses and larger organisations. Consequently, one of the secondary objectives of the paper is to derive characteristics that define IT governance in small businesses. Another secondary objective is to implement the ITGovSB framework at a small business to evaluate its effectiveness.
- Full Text:
- Date Issued: 2009
- Authors: Koornhof, Herman
- Date: 2009
- Subjects: Corporate governance -- South Africa , Organizational effectiveness -- South Africa , Organisational Management
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9768 , http://hdl.handle.net/10948/994 , Corporate governance -- South Africa , Organizational effectiveness -- South Africa , Organisational Management
- Description: The primary objective of this treatise is to develop a framework that small businesses can use to implement IT governance. This framework for IT 6 Governance in Small Businesses, called ITGovSB, will be based primarily on the CobiT framework and the ISO/IEC 27002 information security controls. In order to achieve the primary objective, it is necessary to understand the differences between IT governance in small businesses and larger organisations. Consequently, one of the secondary objectives of the paper is to derive characteristics that define IT governance in small businesses. Another secondary objective is to implement the ITGovSB framework at a small business to evaluate its effectiveness.
- Full Text:
- Date Issued: 2009
A framework for the secure use of portable storage devices : a South African higher education perspective
- Authors: Rothman, Jonathan Sean
- Date: 2009
- Subjects: Computer storage devices , Computer storage devices -- Management , Education, Higher -- Computer network resources
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9766 , http://hdl.handle.net/10948/1054 , Computer storage devices , Computer storage devices -- Management , Education, Higher -- Computer network resources
- Description: South African Higher Education has gone through various changes and challenges, one of these being the merger process. Various Universities and Technikons were forced to merge in an effort to aid the transformation and restructuring of the Higher Education landscape in the post-apartheid era. From an ICT point of view, the merged Institutions ended up with massive and distributed computing facilities. These facilities must be managed and secured and it can be appreciated that the complexity and magnitude of this task is compounded by the large and varied user population (i.e. students) using the facilities. With the exploding use of mobile consumer devices (such as cell phones, personal digital assistants, MP3 players, portable storage devices such as flash drives, etc), Higher Education Institutions are faced with the even more complex task of managing and securing the computing infrastructure, while large numbers of students can enter computer labs and use these devices at random. In some circles, portable devices are touted to be the next panacea in higher education. This, together with the popularity these devices enjoy under the student body, makes it a fait accompli that mobile consumer devices are “here to stay”. Therefore, banning these devices from campus computer labs, is not viable. Universities have to find ways to address security issues through the implementation of appropriate protective measures. This research focuses on finding a solution to mitigating the risks imposed on Higher Education Institutions in South Africa caused by the use of portable storage devices. The research proposes a framework which serves as an outline for the countermeasures that Universities must implement to mitigate the risks inherent to the use of portable storage devices. The scope of the research is limited to flash drives, smart phones and MP3 players.
- Full Text:
- Date Issued: 2009
- Authors: Rothman, Jonathan Sean
- Date: 2009
- Subjects: Computer storage devices , Computer storage devices -- Management , Education, Higher -- Computer network resources
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9766 , http://hdl.handle.net/10948/1054 , Computer storage devices , Computer storage devices -- Management , Education, Higher -- Computer network resources
- Description: South African Higher Education has gone through various changes and challenges, one of these being the merger process. Various Universities and Technikons were forced to merge in an effort to aid the transformation and restructuring of the Higher Education landscape in the post-apartheid era. From an ICT point of view, the merged Institutions ended up with massive and distributed computing facilities. These facilities must be managed and secured and it can be appreciated that the complexity and magnitude of this task is compounded by the large and varied user population (i.e. students) using the facilities. With the exploding use of mobile consumer devices (such as cell phones, personal digital assistants, MP3 players, portable storage devices such as flash drives, etc), Higher Education Institutions are faced with the even more complex task of managing and securing the computing infrastructure, while large numbers of students can enter computer labs and use these devices at random. In some circles, portable devices are touted to be the next panacea in higher education. This, together with the popularity these devices enjoy under the student body, makes it a fait accompli that mobile consumer devices are “here to stay”. Therefore, banning these devices from campus computer labs, is not viable. Universities have to find ways to address security issues through the implementation of appropriate protective measures. This research focuses on finding a solution to mitigating the risks imposed on Higher Education Institutions in South Africa caused by the use of portable storage devices. The research proposes a framework which serves as an outline for the countermeasures that Universities must implement to mitigate the risks inherent to the use of portable storage devices. The scope of the research is limited to flash drives, smart phones and MP3 players.
- Full Text:
- Date Issued: 2009
A framework towards effective control in information security governance
- Authors: Viljoen, Melanie
- Date: 2009
- Subjects: Data protection , Computer networks -- Security measures , Electronic data processing departments -- Security measures
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9773 , http://hdl.handle.net/10948/887 , Data protection , Computer networks -- Security measures , Electronic data processing departments -- Security measures
- Description: The importance of information in business today has made the need to properly secure this asset evident. Information security has become a responsibility for all managers of an organization. To better support more efficient management of information security, timely information security management information should be made available to all managers. Smaller organizations face special challenges with regard to information security management and reporting due to limited resources (Ross, 2008). This dissertation discusses a Framework for Information Security Management Information (FISMI) that aims to improve the visibility and contribute to better management of information security throughout an organization by enabling the provision of summarized, comprehensive information security management information to all managers in an affordable manner.
- Full Text:
- Date Issued: 2009
- Authors: Viljoen, Melanie
- Date: 2009
- Subjects: Data protection , Computer networks -- Security measures , Electronic data processing departments -- Security measures
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9773 , http://hdl.handle.net/10948/887 , Data protection , Computer networks -- Security measures , Electronic data processing departments -- Security measures
- Description: The importance of information in business today has made the need to properly secure this asset evident. Information security has become a responsibility for all managers of an organization. To better support more efficient management of information security, timely information security management information should be made available to all managers. Smaller organizations face special challenges with regard to information security management and reporting due to limited resources (Ross, 2008). This dissertation discusses a Framework for Information Security Management Information (FISMI) that aims to improve the visibility and contribute to better management of information security throughout an organization by enabling the provision of summarized, comprehensive information security management information to all managers in an affordable manner.
- Full Text:
- Date Issued: 2009
A model for enhancing presence handling in instant messaging
- Authors: Victor, Rudi
- Date: 2009
- Subjects: Instant messaging , Mobile communication systems , Data transmission systems
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9774 , http://hdl.handle.net/10948/877 , Instant messaging , Mobile communication systems , Data transmission systems
- Description: Instant Messaging (IM) is becoming increasingly popular in social as well as workplace environments. In fact, many employees use the same IM client to communicate with both colleagues and social contacts. Thus, there are valid concerns about the impact of IM on employee productivity. One of the major advantages of IM over other workplace communication tools such as e-mail and the telephone is the implementation of presence information. In particular, presence awareness is used to determine the avail- ability and willingness of a contact to engage in communication. A current problem with IM is the one-for-all approach to presence: all contacts receive the same set of presence information. However, presence is rooted in social psychology where it is known that the awareness of another person changes the behavior of oneself. Therefore the identity of a contact affects the availability and willingness directed towards that contact. In order for presence information to be provided to contacts, it must be represented in some type of data format. The Internet Engineering Task Force (IETF) has done much work in standardizing IM and presence systems. In particular their data format for presence describes a rich set of presence information including, but not limited to, location, activity, awareness, and mood information. Such information may be sensitive and access to it needs to be controlled to ensure privacy. As with access control policies, managing the information as the number of contacts increases becomes cumbersome and complex. This dissertation draws on the theoretical foundations of presence, current standards in the domain of IM, and lessons from access control to present an enhanced presence handling model for IM. The model is developed in stages, with each stage providing a specific improvement. The first stage of the model is grounded on the current work of the IETF. As such it distributes presence on a per-watcher basis. In the second stage of the model watchers fulfill a specific role and based on this role they receive only the entrusted presence information. In practice, it implies that a "friend" may get more (or less) information than a "colleague". The third stage of the model introduces the concept of availability profiles by drawing on social awareness principles. Availability profiles add the ability to transform presence and change the presentity's behavior to incoming messages according to the provided presence information. Finally the dissertation reports on the development of the RoBIM (Role- Based Instant Messenger) prototype. RoBIM is a standards-based IM system that conforms to the IETF SIMPLE protocol and provides various standard IM features. Here, RoBIM serves as a proof-of-concept for the proposed model. This study contributed to the domain of IM and presence by addressing some of the current presence handling issues. Most importantly, the proposed model takes into account the interpersonal effects of individualizing presence information for different contacts. Thus, the model challenges conventional thought and implementation of presence in IM.
- Full Text:
- Date Issued: 2009
- Authors: Victor, Rudi
- Date: 2009
- Subjects: Instant messaging , Mobile communication systems , Data transmission systems
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9774 , http://hdl.handle.net/10948/877 , Instant messaging , Mobile communication systems , Data transmission systems
- Description: Instant Messaging (IM) is becoming increasingly popular in social as well as workplace environments. In fact, many employees use the same IM client to communicate with both colleagues and social contacts. Thus, there are valid concerns about the impact of IM on employee productivity. One of the major advantages of IM over other workplace communication tools such as e-mail and the telephone is the implementation of presence information. In particular, presence awareness is used to determine the avail- ability and willingness of a contact to engage in communication. A current problem with IM is the one-for-all approach to presence: all contacts receive the same set of presence information. However, presence is rooted in social psychology where it is known that the awareness of another person changes the behavior of oneself. Therefore the identity of a contact affects the availability and willingness directed towards that contact. In order for presence information to be provided to contacts, it must be represented in some type of data format. The Internet Engineering Task Force (IETF) has done much work in standardizing IM and presence systems. In particular their data format for presence describes a rich set of presence information including, but not limited to, location, activity, awareness, and mood information. Such information may be sensitive and access to it needs to be controlled to ensure privacy. As with access control policies, managing the information as the number of contacts increases becomes cumbersome and complex. This dissertation draws on the theoretical foundations of presence, current standards in the domain of IM, and lessons from access control to present an enhanced presence handling model for IM. The model is developed in stages, with each stage providing a specific improvement. The first stage of the model is grounded on the current work of the IETF. As such it distributes presence on a per-watcher basis. In the second stage of the model watchers fulfill a specific role and based on this role they receive only the entrusted presence information. In practice, it implies that a "friend" may get more (or less) information than a "colleague". The third stage of the model introduces the concept of availability profiles by drawing on social awareness principles. Availability profiles add the ability to transform presence and change the presentity's behavior to incoming messages according to the provided presence information. Finally the dissertation reports on the development of the RoBIM (Role- Based Instant Messenger) prototype. RoBIM is a standards-based IM system that conforms to the IETF SIMPLE protocol and provides various standard IM features. Here, RoBIM serves as a proof-of-concept for the proposed model. This study contributed to the domain of IM and presence by addressing some of the current presence handling issues. Most importantly, the proposed model takes into account the interpersonal effects of individualizing presence information for different contacts. Thus, the model challenges conventional thought and implementation of presence in IM.
- Full Text:
- Date Issued: 2009
A qualitative analysis of the cost and management accounting curricula at higher education institutions in South Africa
- Authors: Roodt, Luan
- Date: 2009
- Subjects: Cost accounting -- South Africa , Managerial accounting -- South Africa , Education, Higher -- Curricula -- South Africa , Curriculum planning -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:8973 , http://hdl.handle.net/10948/1202 , Cost accounting -- South Africa , Managerial accounting -- South Africa , Education, Higher -- Curricula -- South Africa , Curriculum planning -- South Africa
- Description: The democracy in South Africa brought about many changes and new challenges. One such challenge was to transform the Higher Education institutes in South Africa. The National Commission on Higher Education (NCHE) resulted in the proposed National Plan for Higher Education in 2001. This referred to the restructuring of Higher Educational Institutes in South Africa. The National Plan for Higher Education listed priorities within section 6, which deals with the restructuring process. Some of these priorities referred to the reduction of duplications and overlaps in the programmes offered. Prior to 2005, Technikons offered the course National Diploma: Cost and Management Accounting over three years. Former Technikons developed their curricula for Cost and Management Accounting to utilise career orientated training in order to provide students with the necessary knowledge and skills for careers in financial and cost and management accounting as was applied in commerce and industry. Before the transformation and restructuring of the South African higher education institutions, Technikons in South Africa was part of a National system where a National curriculum was developed and implemented by all Technikons in South Africa. Curriculum development took place on a national level. Therefore, the programmes offered at these former Technikons were similar. Some of the former Technikons still offer the National Diploma in Cost and Management Accounting but in a different format. Students registering for this programme, register for a National Higher Certificate (NHC) in Accountancy. The duration of this NHC is two years where after students can complete a third year to graduate with a National Diploma in Cost and Management Accounting. The NHC in Accountancy was also developed on a national level and the curricula are similar at the higher education institutions offering it in South Africa. Since the merger of higher education institutions in South Africa, the responsibility to develop new programmes shifted from a national level to an institutional level. The newly merged institutions carry the responsibility to develop new programmes which suites the specific institution and serves the need of the specific communities. The iv primary objective of this study is to analyse the Cost and Management Accounting curricula in South Africa with the intention to propose a new curriculum for this diploma. To suggest a proposed curriculum, the old curricula of the various South African institutions were considered using qualitative research methods. The four South African institutions and the two Australian institutions were analysed and a balanced curriculum proposed out of this information. The proposed curriculum for the diploma in accounting, combined subjects that have been offered previously and subjects that could further expand graduate employability. Five companies were selected to evaluate the proposed curriculum. After considering the views of all the interviewed employers, a final curriculum was suggested for the Diploma in Accounting. As a result of this study it was clear that in-service training should be added to the Diploma in Accounting. Eighty percent of the interviewed potential employers suggested that practical experience in third year studies would significantly enhance student employability. Cost and Management Accounting has long been used by accountants to help managers understand the different costs of running a business. It is important for managers to identify certain areas of the business process where costs can be cut and the profitability increased. From this study it is clear that the proposed curriculum is acceptable to employers as they found that students will benefit from it.
- Full Text:
- Date Issued: 2009
- Authors: Roodt, Luan
- Date: 2009
- Subjects: Cost accounting -- South Africa , Managerial accounting -- South Africa , Education, Higher -- Curricula -- South Africa , Curriculum planning -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:8973 , http://hdl.handle.net/10948/1202 , Cost accounting -- South Africa , Managerial accounting -- South Africa , Education, Higher -- Curricula -- South Africa , Curriculum planning -- South Africa
- Description: The democracy in South Africa brought about many changes and new challenges. One such challenge was to transform the Higher Education institutes in South Africa. The National Commission on Higher Education (NCHE) resulted in the proposed National Plan for Higher Education in 2001. This referred to the restructuring of Higher Educational Institutes in South Africa. The National Plan for Higher Education listed priorities within section 6, which deals with the restructuring process. Some of these priorities referred to the reduction of duplications and overlaps in the programmes offered. Prior to 2005, Technikons offered the course National Diploma: Cost and Management Accounting over three years. Former Technikons developed their curricula for Cost and Management Accounting to utilise career orientated training in order to provide students with the necessary knowledge and skills for careers in financial and cost and management accounting as was applied in commerce and industry. Before the transformation and restructuring of the South African higher education institutions, Technikons in South Africa was part of a National system where a National curriculum was developed and implemented by all Technikons in South Africa. Curriculum development took place on a national level. Therefore, the programmes offered at these former Technikons were similar. Some of the former Technikons still offer the National Diploma in Cost and Management Accounting but in a different format. Students registering for this programme, register for a National Higher Certificate (NHC) in Accountancy. The duration of this NHC is two years where after students can complete a third year to graduate with a National Diploma in Cost and Management Accounting. The NHC in Accountancy was also developed on a national level and the curricula are similar at the higher education institutions offering it in South Africa. Since the merger of higher education institutions in South Africa, the responsibility to develop new programmes shifted from a national level to an institutional level. The newly merged institutions carry the responsibility to develop new programmes which suites the specific institution and serves the need of the specific communities. The iv primary objective of this study is to analyse the Cost and Management Accounting curricula in South Africa with the intention to propose a new curriculum for this diploma. To suggest a proposed curriculum, the old curricula of the various South African institutions were considered using qualitative research methods. The four South African institutions and the two Australian institutions were analysed and a balanced curriculum proposed out of this information. The proposed curriculum for the diploma in accounting, combined subjects that have been offered previously and subjects that could further expand graduate employability. Five companies were selected to evaluate the proposed curriculum. After considering the views of all the interviewed employers, a final curriculum was suggested for the Diploma in Accounting. As a result of this study it was clear that in-service training should be added to the Diploma in Accounting. Eighty percent of the interviewed potential employers suggested that practical experience in third year studies would significantly enhance student employability. Cost and Management Accounting has long been used by accountants to help managers understand the different costs of running a business. It is important for managers to identify certain areas of the business process where costs can be cut and the profitability increased. From this study it is clear that the proposed curriculum is acceptable to employers as they found that students will benefit from it.
- Full Text:
- Date Issued: 2009
An enterprise information security model for a micro finance company: a case study
- Authors: Owen, Morné
- Date: 2009
- Subjects: Computer security -- South Africa -- Management , Computers -- Access control -- South Africa , Computer networks -- Security measures -- Standards -- South Africa , Data protection -- Management -- Standards , Management information systems -- Security measures -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9763 , http://hdl.handle.net/10948/1151 , Computer security -- South Africa -- Management , Computers -- Access control -- South Africa , Computer networks -- Security measures -- Standards -- South Africa , Data protection -- Management -- Standards , Management information systems -- Security measures -- South Africa
- Description: The world has entered the information age. How the information is used within an organization will determine success or failure of the organisation. This study aims to provide a model, that once implemented, will provide the required protection for the information assets. The model is based on ISO 27002, an international security standard. The primary objective is to build a model that will provide a holistic security system specifically for a South African Micro Finance Company (MFC). The secondary objectives focuses on successful implementation of such a model, the uniqueness of the MFC that should be taken into account, and the maintenance of the model once implemented to ensure ongoing relevance. A questionnaire conducted at the MFC provided insight into the perceived understanding of information security. The questionnaire results were used to ensure the model solution addressed current information security shortcomings within the MFC. This study found that the information security controls in ISO 27002 should be applicable to any industry. The uniqueness for the MFC is not in the security controls, but rather in the regulations and laws applicable to it.
- Full Text:
- Date Issued: 2009
- Authors: Owen, Morné
- Date: 2009
- Subjects: Computer security -- South Africa -- Management , Computers -- Access control -- South Africa , Computer networks -- Security measures -- Standards -- South Africa , Data protection -- Management -- Standards , Management information systems -- Security measures -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9763 , http://hdl.handle.net/10948/1151 , Computer security -- South Africa -- Management , Computers -- Access control -- South Africa , Computer networks -- Security measures -- Standards -- South Africa , Data protection -- Management -- Standards , Management information systems -- Security measures -- South Africa
- Description: The world has entered the information age. How the information is used within an organization will determine success or failure of the organisation. This study aims to provide a model, that once implemented, will provide the required protection for the information assets. The model is based on ISO 27002, an international security standard. The primary objective is to build a model that will provide a holistic security system specifically for a South African Micro Finance Company (MFC). The secondary objectives focuses on successful implementation of such a model, the uniqueness of the MFC that should be taken into account, and the maintenance of the model once implemented to ensure ongoing relevance. A questionnaire conducted at the MFC provided insight into the perceived understanding of information security. The questionnaire results were used to ensure the model solution addressed current information security shortcomings within the MFC. This study found that the information security controls in ISO 27002 should be applicable to any industry. The uniqueness for the MFC is not in the security controls, but rather in the regulations and laws applicable to it.
- Full Text:
- Date Issued: 2009
An investigation into guests' perceived service quality of the bed-and-breakfast and guest house market industry in the Nelson Mandela Bay area
- Authors: Zhang, Jin
- Date: 2009
- Subjects: Hospitality industry -- Customer services , Boardinghouses -- Customer services -- South Africa , Bed and breakfast accommodations -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9337 , http://hdl.handle.net/10948/1087
- Description: The tourism and hospitality industry has made a meaningful contribution to the development of the South African economy. Not only the hotels, but also the demand for self-catering holiday properties such as guest houses and bed-and-breakfast Bed and Breakfast establishments is increasing which could boost the tourist industry. Moreover, the prospect of the self-catering holiday properties in South Africa is extremely positive, particularly when the country is given the opportunity to hold the 2010 FIFA World Cup. Thus, expectations and perceptions are significantly shaped and transformed by the prosperous environment. The self-catering holiday properties should provide the best possible service to international and domestic tourists and ensure that their needs are fully met. The general purpose of this study was to evaluate the service quality of guest houses and Bed and Breakfasts in the Nelson Mandela Bay by comparing guests’ expectations and perceptions. The results of this study could assist the managers of guest house and Bed and Breakfast in improving its service performance to more effectively fulfil the needs of dynamic tourist market. The literature study provided an overview of tourism industry from the management and marketing perspectives, services marketing and a detailed discussion of service quality focusing on the nature of services, determinants of service quality and techniques for measuring service quality. The SERVQUAL model and its derivative, Lodging Quality Index (LQI), were adapted for measuring the guests’ perceived service quality in this research. ii The empirical data was collected by means of a survey, using a self-administered questionnaire distributed to guests who were staying at guest houses or Bed and Breakfasts in the Nelson Mandela Bay identified in terms of convenience sampling. One hundred and five useable questionnaires were received. The empirical findings based on the perception-minus-expectation (P-E) gap analysis showed that the perception mean scores were consistently lower than the expectation mean scores. This implies that guests perceived service quality of guest house and Bed and Breakfast to be relatively low. It is recommended that the managers of guest houses and BBs should: uniform the employees; use every tool to figure out what the guest wants; establish specific working procedures and help employees to understand their job responsibilities and mangers’ expectations; invite suggestions of existing located facilities from guests, and move the inconvenient facilities if possible; employ a communication audit to evaluate the overall quality of the communication system by comparing communication objectives to actual performance; combine useful destination information from different sources and update them on the website frequently; and apply an attracting layout to build positive image.
- Full Text:
- Date Issued: 2009
- Authors: Zhang, Jin
- Date: 2009
- Subjects: Hospitality industry -- Customer services , Boardinghouses -- Customer services -- South Africa , Bed and breakfast accommodations -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9337 , http://hdl.handle.net/10948/1087
- Description: The tourism and hospitality industry has made a meaningful contribution to the development of the South African economy. Not only the hotels, but also the demand for self-catering holiday properties such as guest houses and bed-and-breakfast Bed and Breakfast establishments is increasing which could boost the tourist industry. Moreover, the prospect of the self-catering holiday properties in South Africa is extremely positive, particularly when the country is given the opportunity to hold the 2010 FIFA World Cup. Thus, expectations and perceptions are significantly shaped and transformed by the prosperous environment. The self-catering holiday properties should provide the best possible service to international and domestic tourists and ensure that their needs are fully met. The general purpose of this study was to evaluate the service quality of guest houses and Bed and Breakfasts in the Nelson Mandela Bay by comparing guests’ expectations and perceptions. The results of this study could assist the managers of guest house and Bed and Breakfast in improving its service performance to more effectively fulfil the needs of dynamic tourist market. The literature study provided an overview of tourism industry from the management and marketing perspectives, services marketing and a detailed discussion of service quality focusing on the nature of services, determinants of service quality and techniques for measuring service quality. The SERVQUAL model and its derivative, Lodging Quality Index (LQI), were adapted for measuring the guests’ perceived service quality in this research. ii The empirical data was collected by means of a survey, using a self-administered questionnaire distributed to guests who were staying at guest houses or Bed and Breakfasts in the Nelson Mandela Bay identified in terms of convenience sampling. One hundred and five useable questionnaires were received. The empirical findings based on the perception-minus-expectation (P-E) gap analysis showed that the perception mean scores were consistently lower than the expectation mean scores. This implies that guests perceived service quality of guest house and Bed and Breakfast to be relatively low. It is recommended that the managers of guest houses and BBs should: uniform the employees; use every tool to figure out what the guest wants; establish specific working procedures and help employees to understand their job responsibilities and mangers’ expectations; invite suggestions of existing located facilities from guests, and move the inconvenient facilities if possible; employ a communication audit to evaluate the overall quality of the communication system by comparing communication objectives to actual performance; combine useful destination information from different sources and update them on the website frequently; and apply an attracting layout to build positive image.
- Full Text:
- Date Issued: 2009
An investigation into the antimicrobial and anticancer activities of Geranium incanum, Artemisia afra and Artemisia absinthium
- Authors: Freidberg, Ryno
- Date: 2009
- Subjects: Medicinal plants -- South Africa , Cancer -- Alternative treatment -- South Africa , Anti-infective agents
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10122 , http://hdl.handle.net/10948/1045 , Medicinal plants -- South Africa , Cancer -- Alternative treatment -- South Africa , Anti-infective agents
- Description: It has been estimated that between 3000 and 4000 plant species are used for their medicinal properties throughout South Africa, with approximately 27 million South Africans making use of traditional medicines. Of this 27 million, 3 million South Africans rely on traditional medicine as their primary source of health care. Of the 250 000 to 500 000 known plant species, very few have been investigated for their pharmacological qualities, and compounds of significant medicinal value may still remain undiscovered in many plant species. The aims of this study included investigating the antimicrobial properties of Geranium incanum and Artemisia afra, both plants traditionally used for their medicinal properties, and comparing the antimicrobial activity of the latter to that of Artemisia absinthium, as well as investigating the anticancer properties of G. incanum and A. afra, and comparing the anticancer activity of the latter to that of A. absinthium. Infusions, aqueous-, methanol- and acetone extracts of the three plants were prepared and used for anticancer and antimicrobial screening. Plant specimens used to prepare extracts for antimicrobial activity were collected and extracted over three seasons, while extracts used for anticancer screening were prepared from plants collected during the summer only. Considerable variation existed in the percentage crude extract yields obtained when different extractants were used, while the season in which the plants were harvested and extracted also appeared to play a significant role in the amount of extract obtained. The plant extracts were screened for antimicrobial activity against various strains of Candida albicans, Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus and Bacillus cereus, using an agar dilution method. G. incanum and A. afra possessed activity for C. albicans, while all three plants showed activity for S. aureus and B. cereus. Activity was largely dependent on the extraction method used. iii The 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay was used to screen for anticancer activity of the respective extracts, at varying concentrations, against MCF-7 (human breast adenocarcinoma) cells, HT-29 (human colonic adenocarcinoma) cells and HeLa (human cervical cancer) cells. All of the extracts showed cytotoxic activity in all three cell lines to varying extents, depending on the extract used and cell line screened. The acetone extract of A. afra proved to be the most effective inhibitor with the lowest IC50 (2.65 ± 1.05 μg/ml) having been shown in MCF-7 cells. A. afra and A. absinthium showed similar inhibitory patterns, with the methanol- and acetone extracts having been the most potent inhibitors of each of the respective cell lines in general. Fluorescence microscopy employing 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) and propidium iodide (PI) staining indicated that the acetone extract of A. afra induces apoptosis in MCF-7 cells as apposed to necrosis, and the results were comparable to those obtained for cells exposed to cisplatin. Screening of the A. afra acetone extract for toxicity in normal human cells using the CellTiter-Blue® assay indicated the extract to be toxic to peripheral blood mononuclear cells (PBMC’s) at concentrations comparable to that for MCF-7 cells, while cell cycle analysis of MCF-7 cells exposed to the A. afra acetone extract indicated the extract’s ability to induce apoptosis comparable to that of cisplatin, with the extract exerting its activity at a point during or just prior to the S phase of the cell cycle.
- Full Text:
- Date Issued: 2009
- Authors: Freidberg, Ryno
- Date: 2009
- Subjects: Medicinal plants -- South Africa , Cancer -- Alternative treatment -- South Africa , Anti-infective agents
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10122 , http://hdl.handle.net/10948/1045 , Medicinal plants -- South Africa , Cancer -- Alternative treatment -- South Africa , Anti-infective agents
- Description: It has been estimated that between 3000 and 4000 plant species are used for their medicinal properties throughout South Africa, with approximately 27 million South Africans making use of traditional medicines. Of this 27 million, 3 million South Africans rely on traditional medicine as their primary source of health care. Of the 250 000 to 500 000 known plant species, very few have been investigated for their pharmacological qualities, and compounds of significant medicinal value may still remain undiscovered in many plant species. The aims of this study included investigating the antimicrobial properties of Geranium incanum and Artemisia afra, both plants traditionally used for their medicinal properties, and comparing the antimicrobial activity of the latter to that of Artemisia absinthium, as well as investigating the anticancer properties of G. incanum and A. afra, and comparing the anticancer activity of the latter to that of A. absinthium. Infusions, aqueous-, methanol- and acetone extracts of the three plants were prepared and used for anticancer and antimicrobial screening. Plant specimens used to prepare extracts for antimicrobial activity were collected and extracted over three seasons, while extracts used for anticancer screening were prepared from plants collected during the summer only. Considerable variation existed in the percentage crude extract yields obtained when different extractants were used, while the season in which the plants were harvested and extracted also appeared to play a significant role in the amount of extract obtained. The plant extracts were screened for antimicrobial activity against various strains of Candida albicans, Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus and Bacillus cereus, using an agar dilution method. G. incanum and A. afra possessed activity for C. albicans, while all three plants showed activity for S. aureus and B. cereus. Activity was largely dependent on the extraction method used. iii The 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) assay was used to screen for anticancer activity of the respective extracts, at varying concentrations, against MCF-7 (human breast adenocarcinoma) cells, HT-29 (human colonic adenocarcinoma) cells and HeLa (human cervical cancer) cells. All of the extracts showed cytotoxic activity in all three cell lines to varying extents, depending on the extract used and cell line screened. The acetone extract of A. afra proved to be the most effective inhibitor with the lowest IC50 (2.65 ± 1.05 μg/ml) having been shown in MCF-7 cells. A. afra and A. absinthium showed similar inhibitory patterns, with the methanol- and acetone extracts having been the most potent inhibitors of each of the respective cell lines in general. Fluorescence microscopy employing 4',6-diamidino-2-phenylindole dihydrochloride (DAPI) and propidium iodide (PI) staining indicated that the acetone extract of A. afra induces apoptosis in MCF-7 cells as apposed to necrosis, and the results were comparable to those obtained for cells exposed to cisplatin. Screening of the A. afra acetone extract for toxicity in normal human cells using the CellTiter-Blue® assay indicated the extract to be toxic to peripheral blood mononuclear cells (PBMC’s) at concentrations comparable to that for MCF-7 cells, while cell cycle analysis of MCF-7 cells exposed to the A. afra acetone extract indicated the extract’s ability to induce apoptosis comparable to that of cisplatin, with the extract exerting its activity at a point during or just prior to the S phase of the cell cycle.
- Full Text:
- Date Issued: 2009
An investigation into user interface factors impacting on user experience: Pastel accounting case study
- Authors: Mashapa, Job
- Date: 2009
- Subjects: User interfaces (Computer systems) -- South Africa , Accounting -- Data processing , Accounting -- Computer programs , Small business -- South Africa -- Computer network resources
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9762 , http://hdl.handle.net/10948/1184 , User interfaces (Computer systems) -- South Africa , Accounting -- Data processing , Accounting -- Computer programs , Small business -- South Africa -- Computer network resources
- Description: The purpose of this research is to propose metrics to evaluate the user interface factors that impact on the user experience of Software Accounting Applications (SAAs) used to support the accounting business activities in Small Medium and Micro Enterprises (SMMEs) operating in developing countries. The research commences by outlining the conceptual background that introduces the study. In the introductory chapter, the problems together with the objectives that motivate the significance of the study are presented. In the same chapter, the overall research focus and how each of the research questions are treated to accomplish the intended goals are defined. In Chapter 2, the typical accounting business activities for SMMEs operating in developing countries are investigated. Findings from the preliminary survey revealed that Pastel accounting is the commonly used SMME accounting application used in developing countries. Inventory management, cash book processing, preparation of financial statements, customer and supplier documents processing are revealed as the most prevalent SMME accounting activities. This chapter highlights the problems that inhibit the implementation and the delivery of full benefits of using these SAAs. After indentifying the SAA problems, user experience aspects of the SAA are addressed in Chapter 3. User experience (UX) is defined and existing UX evaluation criteria are discussed. The findings form the basis for choosing the applicable criteria for evaluating the User Interface (UI) factors impacting on the UX of Pastel accounting. The proposed user experience evaluation metrics are described in Chapter 4. A discussion on how the metrics are implemented and what UI aspect they measure is presented. The research design and methodology followed is discussed in Chapter 5. The chapter outlines the possible research philosophy, strategy, methods and data collecting methods. A choice is made about the appropriate approach to answer the stated research questions to satisfy the intended overall research objective. A phenomenologist, qualitative inductive approach is adopted in the study. A contextual inquiry case-study strategy is chosen as applicable to this research. Data is collected using expert reviews, user observation and subjective questionnaires. After the choice of the research techniques, the case study results are presented and analysed in Chapter 6. It is found that Pastel UI is attractive and the users are happy with the visual design of the application. The major factors that impact on Pastel accounting are its lack of 4 feedback and its complexity which makes it difficult for first time users to use the application and the paucity of the help function. After the observed findings, the conclusions and recommendations of the research are presented in Chapter 7. It has been concluded that Pastel accounting UI fails to captivate a positive user experience for first-time users; the users do not find the expected help from the Help function and are often left wondering about the status of the system and the outcome of their actions on a task. Recommendations on how designers would make Pastel user interface more helpful, easy to use, and provide adequate feedback are presented in Chapter 7.
- Full Text:
- Date Issued: 2009
- Authors: Mashapa, Job
- Date: 2009
- Subjects: User interfaces (Computer systems) -- South Africa , Accounting -- Data processing , Accounting -- Computer programs , Small business -- South Africa -- Computer network resources
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9762 , http://hdl.handle.net/10948/1184 , User interfaces (Computer systems) -- South Africa , Accounting -- Data processing , Accounting -- Computer programs , Small business -- South Africa -- Computer network resources
- Description: The purpose of this research is to propose metrics to evaluate the user interface factors that impact on the user experience of Software Accounting Applications (SAAs) used to support the accounting business activities in Small Medium and Micro Enterprises (SMMEs) operating in developing countries. The research commences by outlining the conceptual background that introduces the study. In the introductory chapter, the problems together with the objectives that motivate the significance of the study are presented. In the same chapter, the overall research focus and how each of the research questions are treated to accomplish the intended goals are defined. In Chapter 2, the typical accounting business activities for SMMEs operating in developing countries are investigated. Findings from the preliminary survey revealed that Pastel accounting is the commonly used SMME accounting application used in developing countries. Inventory management, cash book processing, preparation of financial statements, customer and supplier documents processing are revealed as the most prevalent SMME accounting activities. This chapter highlights the problems that inhibit the implementation and the delivery of full benefits of using these SAAs. After indentifying the SAA problems, user experience aspects of the SAA are addressed in Chapter 3. User experience (UX) is defined and existing UX evaluation criteria are discussed. The findings form the basis for choosing the applicable criteria for evaluating the User Interface (UI) factors impacting on the UX of Pastel accounting. The proposed user experience evaluation metrics are described in Chapter 4. A discussion on how the metrics are implemented and what UI aspect they measure is presented. The research design and methodology followed is discussed in Chapter 5. The chapter outlines the possible research philosophy, strategy, methods and data collecting methods. A choice is made about the appropriate approach to answer the stated research questions to satisfy the intended overall research objective. A phenomenologist, qualitative inductive approach is adopted in the study. A contextual inquiry case-study strategy is chosen as applicable to this research. Data is collected using expert reviews, user observation and subjective questionnaires. After the choice of the research techniques, the case study results are presented and analysed in Chapter 6. It is found that Pastel UI is attractive and the users are happy with the visual design of the application. The major factors that impact on Pastel accounting are its lack of 4 feedback and its complexity which makes it difficult for first time users to use the application and the paucity of the help function. After the observed findings, the conclusions and recommendations of the research are presented in Chapter 7. It has been concluded that Pastel accounting UI fails to captivate a positive user experience for first-time users; the users do not find the expected help from the Help function and are often left wondering about the status of the system and the outcome of their actions on a task. Recommendations on how designers would make Pastel user interface more helpful, easy to use, and provide adequate feedback are presented in Chapter 7.
- Full Text:
- Date Issued: 2009
An investigation into visitors' satisfaction with Port Elizabeth's heritage museums
- Hou, Yue
- Authors: Hou, Yue
- Date: 2009
- Subjects: Art museum attendance -- South Africa -- Port Elizabeth , Customer satisfaction -- South Africa -- Port Elizabeth , Heritage tourism -- South Africa -- Port Elizabeth , Museums -- South Africa -- Port Elizabeth , Tourism -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9361 , http://hdl.handle.net/10948/1250 , Art museum attendance -- South Africa -- Port Elizabeth , Customer satisfaction -- South Africa -- Port Elizabeth , Heritage tourism -- South Africa -- Port Elizabeth , Museums -- South Africa -- Port Elizabeth , Tourism -- South Africa -- Port Elizabeth
- Description: Cultural and heritage tourism, one of the fastest growing segments of the tourism industry, is becoming a major pillar in the tourism strategy of many countries. Like elsewhere in the world, museums play a significant role in heritage tourism. South Africa has a rich history of intangible cultural heritage which manifests itself in oral history, traditional music and dance, social practices and indigenous knowledge systems. It is becoming more important for museum managers to identify the variables that will enhance the attraction and retention of museum visitors. The aim of the study was to determine tourists’ satisfaction with their visit to Port Elizabeth’s heritage museums by comparing their expectations and experiences. This could help museum marketers to better understand their customers, and design experiences that match their expectations. The literature review presented a brief overview of heritage tourism, the museum experience, and visitors’ satisfaction. Concepts of heritage tourism, functions of museums and the different museum attributes that might impact customer satisfaction were discussed. Literature on visitors’ satisfaction included descriptions of the expectations and approaches to measuring customer satisfaction. A museum satisfaction conceptual model resulted from these reviews. ii The proposed model was modified in the empirical study. The data were collected by means of a survey, using self-administered questionnaires distributed to visitors at three heritage museums in Port Elizabeth. Two hundred and twelve useable questionnaires were received. The empirical findings did not fully support the conceptual model. By conducting a factor analysis, the data was reduced to eight factors, namely, human interaction, physical evidence, facilities, facility quality, exhibition, edutainment, escape and aestheticism. It was found that the satisfaction mean scores were consistently higher than the expectation mean scores. This implies that museum visitors were satisfied with their experience of the three heritage museums in Port Elizabeth. Finally, the results of the paired sample t-test and regression analyses tested and explained formulated hypotheses. The principal recommendations emanating from this study are summarised in two groups, namely: • recommendations pertaining to the strategic implications of the findings in terms of service, facilities and experience. For example, the museum administration could establish more facilities for the disabled and the elderly, consider discounting and promotion programmes, and increase the use of technology in their displays. • recommendations for future research. For example, future studies could be applied to investigate visitors’ satisfaction with other heritage museums in South Africa.
- Full Text:
- Date Issued: 2009
- Authors: Hou, Yue
- Date: 2009
- Subjects: Art museum attendance -- South Africa -- Port Elizabeth , Customer satisfaction -- South Africa -- Port Elizabeth , Heritage tourism -- South Africa -- Port Elizabeth , Museums -- South Africa -- Port Elizabeth , Tourism -- South Africa -- Port Elizabeth
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9361 , http://hdl.handle.net/10948/1250 , Art museum attendance -- South Africa -- Port Elizabeth , Customer satisfaction -- South Africa -- Port Elizabeth , Heritage tourism -- South Africa -- Port Elizabeth , Museums -- South Africa -- Port Elizabeth , Tourism -- South Africa -- Port Elizabeth
- Description: Cultural and heritage tourism, one of the fastest growing segments of the tourism industry, is becoming a major pillar in the tourism strategy of many countries. Like elsewhere in the world, museums play a significant role in heritage tourism. South Africa has a rich history of intangible cultural heritage which manifests itself in oral history, traditional music and dance, social practices and indigenous knowledge systems. It is becoming more important for museum managers to identify the variables that will enhance the attraction and retention of museum visitors. The aim of the study was to determine tourists’ satisfaction with their visit to Port Elizabeth’s heritage museums by comparing their expectations and experiences. This could help museum marketers to better understand their customers, and design experiences that match their expectations. The literature review presented a brief overview of heritage tourism, the museum experience, and visitors’ satisfaction. Concepts of heritage tourism, functions of museums and the different museum attributes that might impact customer satisfaction were discussed. Literature on visitors’ satisfaction included descriptions of the expectations and approaches to measuring customer satisfaction. A museum satisfaction conceptual model resulted from these reviews. ii The proposed model was modified in the empirical study. The data were collected by means of a survey, using self-administered questionnaires distributed to visitors at three heritage museums in Port Elizabeth. Two hundred and twelve useable questionnaires were received. The empirical findings did not fully support the conceptual model. By conducting a factor analysis, the data was reduced to eight factors, namely, human interaction, physical evidence, facilities, facility quality, exhibition, edutainment, escape and aestheticism. It was found that the satisfaction mean scores were consistently higher than the expectation mean scores. This implies that museum visitors were satisfied with their experience of the three heritage museums in Port Elizabeth. Finally, the results of the paired sample t-test and regression analyses tested and explained formulated hypotheses. The principal recommendations emanating from this study are summarised in two groups, namely: • recommendations pertaining to the strategic implications of the findings in terms of service, facilities and experience. For example, the museum administration could establish more facilities for the disabled and the elderly, consider discounting and promotion programmes, and increase the use of technology in their displays. • recommendations for future research. For example, future studies could be applied to investigate visitors’ satisfaction with other heritage museums in South Africa.
- Full Text:
- Date Issued: 2009
Biological activities of medicinal plants traditionally used to treat Septicaemia in the Eastern Cape, South Africa
- Authors: Chinyama, Robert Fred
- Date: 2009
- Subjects: Materia medica, Vegetable -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Herbs -- Therapeutic use -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10119 , http://hdl.handle.net/10948/1274 , Materia medica, Vegetable -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Herbs -- Therapeutic use -- South Africa -- Eastern Cape
- Description: Over the past 25 years, there has been a resurgence of worldwide scientific research in the fields of ethnopharmacology. The Western world has acknowledged the continued use of traditional medicines by the majority of third world countries, and the need for novel drug development. Hence, much of the pharmaceutical research in recent years has focused on the ethnobotanical approach to drug discovery (Light et al., 2005). In South Africa, as in most developing parts of the world, traditional herbal medicine still forms the backbone of rural healthcare. The government health services in South Africa provide only western medical care although the majority of the population consult traditional healers for some or all of their healthcare needs (McGaw et al., 2005). Medicinal plants like Harpephyllum caffrum are used as blood purifiers or emetics (Watt and Breyer-Brandwijk, 1962), and also for treating acne and eczema. The antimicrobial activity of this plant can be used to treat septicaemia, which is ranked the sixth leading cause of death among neonates and the eighth leading cause of death for infants through the first year of life (Heron, 2007). In this study, the plants investigated for antimicrobial activity were Harpephyllum caffrum, Hermannia cuneifolia, Chironia baccifera, Rhigozum obovatum, Felicia muricata and Pentzia incana. These plants were tested against ATTC (American Type Culture Collection) strains and microorganisms isolated from clinical isolates of patients suffering from septicaemia. The assay methods used included the agar diffusion method using the Mast multipoint inoculator, the microtitre dilution method were used to determine the minimum inhibitory concentration, thin layer chromatography fingerprints accompanied by bioautographic assay were used to detect the inhibition of bacterial growth by active compounds separated from plant extracts and the Ames test was required to assess the possibility of bacterial mutagenesis upon the exposure to plant extracts which can lead to carcinogenicity. In agar diffusion method, extracts of Harpephyllum caffrum inhibited nine strains of Candida albicans, three species of Acinetobacter and four strains of E.faecalis. Extracts of Hermannia cuneifolia inhibited four strains of B.cereus and three strains of Staphylococcus aureus. Extracts of Chironia baccifera inhibited one strain of Acinetobacter and five strains of E.faecalis. Extracts of plants Rhigozum obovatum, Felicia muricata, and Pentzia incana showed no antimicrobial activity. In the microtitre dilution method used to determine the minimum inhibitory concentration (MIC), the results were different from the agar diffusion method. More activity was observed. Extracts of Harpephyllum caffrum inhibited three strains of E.coli, six strains of S.aureus, three species of Acinetobacter and one strain of Klebsiella pneumonia. Extracts of Hermannia cuneifolia inhibited four strains of B.cereus, three strains of S.aureus, two strains of K.oxytoca and one species of Acinetobacter. Extracts of Chironia baccifera inhibited three strains of S.aureus, one strain of MRSA, one species of Acinetobacter and one strain of S.haemolyticus. The MIC values ranged from 0.049 to 6.25mg/ml. Using the thin layer chromatography fingerprints, bioautography showed the presence of various inhibitory chemical compounds. Methanol and acetone extracts of Harpephyllum caffrum, separated very well and showed various inhibition zones on exposure to Candida albicans, Enterococcus faecalis and Staphylococcus aureus. The different inhibition zones were recorded as Rf In the Ames test (Maron and Ames, 1983) the methanol and acetone extracts of Harpephyllum caffrum and Hermannia cuneifolia were negative which means they were devoid of any mutagenic properties. Methanol extracts of Harpephyllum caffrum showed similar results in the Ames assay as reported by Verschaeve and Van Staden (2008). values ranging from 0.25 to 0.95. The zones indicate the different inhibiting chemical compounds present in the plant. Petroleum ether, ethyl acetate, chloroform and formic acid were the solvents used in the assay in the ratio 8:7:5:1, respectively. Establishing the antimicrobial activity of these plants contribute to the systematic scientific investigation of indigenous South African medicinal plants.
- Full Text:
- Date Issued: 2009
- Authors: Chinyama, Robert Fred
- Date: 2009
- Subjects: Materia medica, Vegetable -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Herbs -- Therapeutic use -- South Africa -- Eastern Cape
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:10119 , http://hdl.handle.net/10948/1274 , Materia medica, Vegetable -- South Africa -- Eastern Cape , Medicinal plants -- South Africa -- Eastern Cape , Traditional medicine -- South Africa -- Eastern Cape , Herbs -- Therapeutic use -- South Africa -- Eastern Cape
- Description: Over the past 25 years, there has been a resurgence of worldwide scientific research in the fields of ethnopharmacology. The Western world has acknowledged the continued use of traditional medicines by the majority of third world countries, and the need for novel drug development. Hence, much of the pharmaceutical research in recent years has focused on the ethnobotanical approach to drug discovery (Light et al., 2005). In South Africa, as in most developing parts of the world, traditional herbal medicine still forms the backbone of rural healthcare. The government health services in South Africa provide only western medical care although the majority of the population consult traditional healers for some or all of their healthcare needs (McGaw et al., 2005). Medicinal plants like Harpephyllum caffrum are used as blood purifiers or emetics (Watt and Breyer-Brandwijk, 1962), and also for treating acne and eczema. The antimicrobial activity of this plant can be used to treat septicaemia, which is ranked the sixth leading cause of death among neonates and the eighth leading cause of death for infants through the first year of life (Heron, 2007). In this study, the plants investigated for antimicrobial activity were Harpephyllum caffrum, Hermannia cuneifolia, Chironia baccifera, Rhigozum obovatum, Felicia muricata and Pentzia incana. These plants were tested against ATTC (American Type Culture Collection) strains and microorganisms isolated from clinical isolates of patients suffering from septicaemia. The assay methods used included the agar diffusion method using the Mast multipoint inoculator, the microtitre dilution method were used to determine the minimum inhibitory concentration, thin layer chromatography fingerprints accompanied by bioautographic assay were used to detect the inhibition of bacterial growth by active compounds separated from plant extracts and the Ames test was required to assess the possibility of bacterial mutagenesis upon the exposure to plant extracts which can lead to carcinogenicity. In agar diffusion method, extracts of Harpephyllum caffrum inhibited nine strains of Candida albicans, three species of Acinetobacter and four strains of E.faecalis. Extracts of Hermannia cuneifolia inhibited four strains of B.cereus and three strains of Staphylococcus aureus. Extracts of Chironia baccifera inhibited one strain of Acinetobacter and five strains of E.faecalis. Extracts of plants Rhigozum obovatum, Felicia muricata, and Pentzia incana showed no antimicrobial activity. In the microtitre dilution method used to determine the minimum inhibitory concentration (MIC), the results were different from the agar diffusion method. More activity was observed. Extracts of Harpephyllum caffrum inhibited three strains of E.coli, six strains of S.aureus, three species of Acinetobacter and one strain of Klebsiella pneumonia. Extracts of Hermannia cuneifolia inhibited four strains of B.cereus, three strains of S.aureus, two strains of K.oxytoca and one species of Acinetobacter. Extracts of Chironia baccifera inhibited three strains of S.aureus, one strain of MRSA, one species of Acinetobacter and one strain of S.haemolyticus. The MIC values ranged from 0.049 to 6.25mg/ml. Using the thin layer chromatography fingerprints, bioautography showed the presence of various inhibitory chemical compounds. Methanol and acetone extracts of Harpephyllum caffrum, separated very well and showed various inhibition zones on exposure to Candida albicans, Enterococcus faecalis and Staphylococcus aureus. The different inhibition zones were recorded as Rf In the Ames test (Maron and Ames, 1983) the methanol and acetone extracts of Harpephyllum caffrum and Hermannia cuneifolia were negative which means they were devoid of any mutagenic properties. Methanol extracts of Harpephyllum caffrum showed similar results in the Ames assay as reported by Verschaeve and Van Staden (2008). values ranging from 0.25 to 0.95. The zones indicate the different inhibiting chemical compounds present in the plant. Petroleum ether, ethyl acetate, chloroform and formic acid were the solvents used in the assay in the ratio 8:7:5:1, respectively. Establishing the antimicrobial activity of these plants contribute to the systematic scientific investigation of indigenous South African medicinal plants.
- Full Text:
- Date Issued: 2009