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From desktop to mobile : a framework for function and content transformation
- Authors: Jurgens, Geert Dirk
- Date: 2011
- Subjects: Mobile computing , Pocket computers
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9752 , http://hdl.handle.net/10948/1429 , Mobile computing , Pocket computers
- Description: The use of mobile phones and other mobile devices are becoming widespread and almost all of these mobile devices have some sort of mobile Internet access. Due to the increase in mobile Internet usage, many websites need altering in order to become mobile compatible. Creating a mobile compatible version of a website is challenging due to formatting and capability restrictions imposed by the mobile device. Currently, one of the popular methods of creating a mobile compatible website involves the creation of a new, dedicated mobile version of the website. However, this approach can prove to be expensive, and repetitive, since a fully functional desktop version of the website often already exists. A second method involves the use of a transformation proxy to transform the traditional website into a mobile compatible version. This research develops a transformation framework that enables a web developer to create a single set of source files that can be used to render output compatible with both traditional and mobile devices. In developing this framework, capabilities and restrictions of the mobile device were examined. Furthermore, current mobile web development guidelines and best practices were discussed. This resulted in the development of a method to identify and outline areas of a traditional website for transformation into a mobile friendly format. Furthermore, a transformation engine that allowed processing of the traditional website into a mobile compatible website was developed. This transformation engine extracted the outlined areas, and rendered the extracted content, all while maintaining the website’s original functionality. The development of a prototype verified that the transformation concepts are valid, and provided for the development of guidelines and recommendations. The development of a framework to enable the web developer to create a website once, and enable it to adapt its output for mobile devices, will have a positive impact on the development of content for the mobile web.
- Full Text:
- Date Issued: 2011
- Authors: Jurgens, Geert Dirk
- Date: 2011
- Subjects: Mobile computing , Pocket computers
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9752 , http://hdl.handle.net/10948/1429 , Mobile computing , Pocket computers
- Description: The use of mobile phones and other mobile devices are becoming widespread and almost all of these mobile devices have some sort of mobile Internet access. Due to the increase in mobile Internet usage, many websites need altering in order to become mobile compatible. Creating a mobile compatible version of a website is challenging due to formatting and capability restrictions imposed by the mobile device. Currently, one of the popular methods of creating a mobile compatible website involves the creation of a new, dedicated mobile version of the website. However, this approach can prove to be expensive, and repetitive, since a fully functional desktop version of the website often already exists. A second method involves the use of a transformation proxy to transform the traditional website into a mobile compatible version. This research develops a transformation framework that enables a web developer to create a single set of source files that can be used to render output compatible with both traditional and mobile devices. In developing this framework, capabilities and restrictions of the mobile device were examined. Furthermore, current mobile web development guidelines and best practices were discussed. This resulted in the development of a method to identify and outline areas of a traditional website for transformation into a mobile friendly format. Furthermore, a transformation engine that allowed processing of the traditional website into a mobile compatible website was developed. This transformation engine extracted the outlined areas, and rendered the extracted content, all while maintaining the website’s original functionality. The development of a prototype verified that the transformation concepts are valid, and provided for the development of guidelines and recommendations. The development of a framework to enable the web developer to create a website once, and enable it to adapt its output for mobile devices, will have a positive impact on the development of content for the mobile web.
- Full Text:
- Date Issued: 2011
The role of psychosocial recuperative therapy in enhancing construction performance on projects
- Authors: Obiozo, Rita Ngozi
- Date: 2018
- Subjects: Building -- Psychological aspects , Construction industry -- Accidents Building -- Economic aspects Feng shui
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/23080 , vital:30414
- Description: Research findings indicate that recent improvements in construction management initiatives have not substantially reduced the incidence of fatal occurrences and accidents in construction due to negligence and error. Some of the traumatic and causative factors include the dissipation of vital energy, health, safety, and wellbeing in the construction workforce due to the lack of contact with nature on construction sites, combined with the exhaustive nature of the work, and multiple stress factors in construction. The resultant effect is visible in the form of increased rework, disputes, and socio-psycho-traumatic factors that result in a reduction in profit margins due to the daily repetition of health and safety (H&S) hazards and quality errors. To address these issues there is a need for the exploration of the inherent potential to achieve exceptional environmental credentials on construction worksites attributable to the biophilic design concept of the intelligent construction workplace. This would involve the introduction of a biophilic construction site model (BCSM) that has the potential of establishing the continuous flow of natural energy that would replenish the vital life force and impact on the improvement of the performance of the construction workforce and management throughout the life cycle of the construction process. The objective of the initiative involves the introduction of dynamic harmonious energy in consonance with the theory of biophilia and feng shui principles of wellness interventions, which would introduce and enhance the flow of natural energy relative to the greening of construction sites in aid of H&S, wellbeing and human factors for ergonomics in construction. The methodology adopted, involved a survey of the related literature, and the triangulation and longitudinal assessment of multiple case studies of viable construction sites in progress. The applied technique included a greening construction site survey, interviews, observations, photo elicitation, questionnaire surveys, and a focus group study conducted with the construction workforce during the construction process. Findings indicate a potential increase in the level of sustainable behaviour in construction that impacts on the enhanced concentration and level of focus of the workforce, as well as a reduction in H&S and quality errors that militate against consistent improvement of the construction process. These efforts add value and novelty to the construction management body of knowledge (CMBOK) with regards to the green building construction and sustainable sites initiative. Research findings established the ‘greening of the construction site / biophilic construction site model (BCSM)’ as a cost-effective strategy towards the healing of the ‘sick construction site syndrome’ and the psychosocial recuperative and rejunative therapy for the workforce in construction for productive performance. It is significant and notable that the empirical findings relative to the BCSM strategy were found to substantiate effectively as the missing link in the establishment and reconstitution of Maslow’s hierarchy of needs, which according to research findings, is currently conceptual. The recommendations include the suggestions for the ‘informal dynamic rock garden design’ as suitable for the BCSM with the inclusion of ‘plants as a primary indicator’ in construction site premises, site offices, material sheds, welfare facilities including ‘lunch break retreats and outdoor shelters’. The recommendation of the BCSM strategy for the construction site is aimed towards the onset of construction as opposed to the conclusion of works / external works at the end of the project as is currently practiced. For effective application, the empirical findings relative to the study recommend that the procurement of the BCSM as a ‘silent and indispensable team mate’ should commence from the conceptual design, pre-bid / tender stages, to the fiscal planning and setting out of worksites, as well as its inclusion in the ‘curriculum of studies’ for the instruction of emerging construction management practitioners. In furtherance of the CMBOK and the enhancement of the BCSM strategy and the ‘humanistic value of the intelligent construction worksite’, the study recommends that the concept of ‘frozen music’ be addressed in future research relative to the ‘biophilic design concept’ to determine its role in enhancing cost effective performance, H&S, ergonomics, and the health and wellbeing of workers in construction.
- Full Text:
- Date Issued: 2018
- Authors: Obiozo, Rita Ngozi
- Date: 2018
- Subjects: Building -- Psychological aspects , Construction industry -- Accidents Building -- Economic aspects Feng shui
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/23080 , vital:30414
- Description: Research findings indicate that recent improvements in construction management initiatives have not substantially reduced the incidence of fatal occurrences and accidents in construction due to negligence and error. Some of the traumatic and causative factors include the dissipation of vital energy, health, safety, and wellbeing in the construction workforce due to the lack of contact with nature on construction sites, combined with the exhaustive nature of the work, and multiple stress factors in construction. The resultant effect is visible in the form of increased rework, disputes, and socio-psycho-traumatic factors that result in a reduction in profit margins due to the daily repetition of health and safety (H&S) hazards and quality errors. To address these issues there is a need for the exploration of the inherent potential to achieve exceptional environmental credentials on construction worksites attributable to the biophilic design concept of the intelligent construction workplace. This would involve the introduction of a biophilic construction site model (BCSM) that has the potential of establishing the continuous flow of natural energy that would replenish the vital life force and impact on the improvement of the performance of the construction workforce and management throughout the life cycle of the construction process. The objective of the initiative involves the introduction of dynamic harmonious energy in consonance with the theory of biophilia and feng shui principles of wellness interventions, which would introduce and enhance the flow of natural energy relative to the greening of construction sites in aid of H&S, wellbeing and human factors for ergonomics in construction. The methodology adopted, involved a survey of the related literature, and the triangulation and longitudinal assessment of multiple case studies of viable construction sites in progress. The applied technique included a greening construction site survey, interviews, observations, photo elicitation, questionnaire surveys, and a focus group study conducted with the construction workforce during the construction process. Findings indicate a potential increase in the level of sustainable behaviour in construction that impacts on the enhanced concentration and level of focus of the workforce, as well as a reduction in H&S and quality errors that militate against consistent improvement of the construction process. These efforts add value and novelty to the construction management body of knowledge (CMBOK) with regards to the green building construction and sustainable sites initiative. Research findings established the ‘greening of the construction site / biophilic construction site model (BCSM)’ as a cost-effective strategy towards the healing of the ‘sick construction site syndrome’ and the psychosocial recuperative and rejunative therapy for the workforce in construction for productive performance. It is significant and notable that the empirical findings relative to the BCSM strategy were found to substantiate effectively as the missing link in the establishment and reconstitution of Maslow’s hierarchy of needs, which according to research findings, is currently conceptual. The recommendations include the suggestions for the ‘informal dynamic rock garden design’ as suitable for the BCSM with the inclusion of ‘plants as a primary indicator’ in construction site premises, site offices, material sheds, welfare facilities including ‘lunch break retreats and outdoor shelters’. The recommendation of the BCSM strategy for the construction site is aimed towards the onset of construction as opposed to the conclusion of works / external works at the end of the project as is currently practiced. For effective application, the empirical findings relative to the study recommend that the procurement of the BCSM as a ‘silent and indispensable team mate’ should commence from the conceptual design, pre-bid / tender stages, to the fiscal planning and setting out of worksites, as well as its inclusion in the ‘curriculum of studies’ for the instruction of emerging construction management practitioners. In furtherance of the CMBOK and the enhancement of the BCSM strategy and the ‘humanistic value of the intelligent construction worksite’, the study recommends that the concept of ‘frozen music’ be addressed in future research relative to the ‘biophilic design concept’ to determine its role in enhancing cost effective performance, H&S, ergonomics, and the health and wellbeing of workers in construction.
- Full Text:
- Date Issued: 2018
The influence of project management service provision on role-players within the South African construction industry
- Authors: Hefer, Andre le Roux
- Date: 2012
- Subjects: Project management -- South Africa , Construction industry -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9663 , http://hdl.handle.net/10948/d1008295 , Project management -- South Africa , Construction industry -- South Africa
- Description: The legitimate existence of the Project Management Profession in the South African construction industry needs to relate to positive project influence on the industry roleplayers. This study assessed the perceived lack of recognition and acceptance of Project Management as a stand-alone profession relating to: · Appointments of Project Managers being questioned due to a perceived lack of influence and impact on project success. · Project Managers not being recognised as an integral part of the industry. · Project Management not being perceived as having a unique and defined function. Interviews were held with 23 industry role-players made up of clients, contractors and consultants. The interviews solicited input on the role-players’ perception and experience related to the influence of Project Management over the past 10 years, not only on a list of success criteria relative to their own role in the industry, but also their perception of the influence on the other defined role-player groups. Included in the interview questionnaire was also a range of general questions to refine the feedback and further test the hypotheses. The data were interpreted and analysed by comparing the feedback of the respondents as a combination and separately as groups. The results of the study indicate that: · Project Management could be seen as a legitimate part of the industry; · The industry role-players perceive Project Management as making an impact and having a growing influence on the industry; A specific but broad set of skills are required by Project Managers; · The Project Management function cannot be fulfilled by other consultants, but there are project related criteria which should be considered before making a final judgment. These criteria relate to project size and complexity; and · Project Management is currently perceived to be more related to a specific person’s skill than to a specific profession. The study’s aim was to influence and inform the views of industry role-players on the appointment of a Project Manager in the construction industry.
- Full Text:
- Date Issued: 2012
- Authors: Hefer, Andre le Roux
- Date: 2012
- Subjects: Project management -- South Africa , Construction industry -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9663 , http://hdl.handle.net/10948/d1008295 , Project management -- South Africa , Construction industry -- South Africa
- Description: The legitimate existence of the Project Management Profession in the South African construction industry needs to relate to positive project influence on the industry roleplayers. This study assessed the perceived lack of recognition and acceptance of Project Management as a stand-alone profession relating to: · Appointments of Project Managers being questioned due to a perceived lack of influence and impact on project success. · Project Managers not being recognised as an integral part of the industry. · Project Management not being perceived as having a unique and defined function. Interviews were held with 23 industry role-players made up of clients, contractors and consultants. The interviews solicited input on the role-players’ perception and experience related to the influence of Project Management over the past 10 years, not only on a list of success criteria relative to their own role in the industry, but also their perception of the influence on the other defined role-player groups. Included in the interview questionnaire was also a range of general questions to refine the feedback and further test the hypotheses. The data were interpreted and analysed by comparing the feedback of the respondents as a combination and separately as groups. The results of the study indicate that: · Project Management could be seen as a legitimate part of the industry; · The industry role-players perceive Project Management as making an impact and having a growing influence on the industry; A specific but broad set of skills are required by Project Managers; · The Project Management function cannot be fulfilled by other consultants, but there are project related criteria which should be considered before making a final judgment. These criteria relate to project size and complexity; and · Project Management is currently perceived to be more related to a specific person’s skill than to a specific profession. The study’s aim was to influence and inform the views of industry role-players on the appointment of a Project Manager in the construction industry.
- Full Text:
- Date Issued: 2012
Establishing the benefits of implementing an I.T. project management office in the Nelson Mandela Metropolitan area
- Martin, Michael Ronald Charles
- Authors: Martin, Michael Ronald Charles
- Date: 2007
- Subjects: Project management -- South Africa -- Port Elizabeth -- Computer network resources , Information technology -- South Africa -- Port Elizabeth -- Management
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9266 , http://hdl.handle.net/10948/558 , Project management -- South Africa -- Port Elizabeth -- Computer network resources , Information technology -- South Africa -- Port Elizabeth -- Management
- Description: The well-known concept of a Project Manager managing an I.T. project in relative isolation is no longer a viable option for organisations that are running numerous projects simultaneously. Due to the enormous costs and risks involved in many of these projects, there needs to be a means to ensure success. This has led to the establishment of the concept of a Project Management Office (PMO). An autonomous business unit that is responsible for managing all projects within an organisation. The need for a Project Management Office (PMO) to effectively manage multiple projects is becoming more and more accepted worldwide. The benefits of a PMO are well documented, but whether these benefits will apply to organisations within the NMM area needed to be investigated. A detailed analysis of the benefits of Project Management and in particular a PMO, have been investigated by means of a literature study. An investigation into the effectiveness of PMO’s in South Africa in general, was conducted by means of a survey targeted at a group of I.T. Project Managers located in all the major centres. A further survey was conducted among local I.T. managers to determine their current level of success and their expectations for the future. When reviewing the expectations of local I.T. management against the performance of Project Managers that are currently operating within PMOs, it is clear that organisations within the NMM area are in need of PMO’s and would certainly benefit from their establishment.
- Full Text:
- Date Issued: 2007
- Authors: Martin, Michael Ronald Charles
- Date: 2007
- Subjects: Project management -- South Africa -- Port Elizabeth -- Computer network resources , Information technology -- South Africa -- Port Elizabeth -- Management
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9266 , http://hdl.handle.net/10948/558 , Project management -- South Africa -- Port Elizabeth -- Computer network resources , Information technology -- South Africa -- Port Elizabeth -- Management
- Description: The well-known concept of a Project Manager managing an I.T. project in relative isolation is no longer a viable option for organisations that are running numerous projects simultaneously. Due to the enormous costs and risks involved in many of these projects, there needs to be a means to ensure success. This has led to the establishment of the concept of a Project Management Office (PMO). An autonomous business unit that is responsible for managing all projects within an organisation. The need for a Project Management Office (PMO) to effectively manage multiple projects is becoming more and more accepted worldwide. The benefits of a PMO are well documented, but whether these benefits will apply to organisations within the NMM area needed to be investigated. A detailed analysis of the benefits of Project Management and in particular a PMO, have been investigated by means of a literature study. An investigation into the effectiveness of PMO’s in South Africa in general, was conducted by means of a survey targeted at a group of I.T. Project Managers located in all the major centres. A further survey was conducted among local I.T. managers to determine their current level of success and their expectations for the future. When reviewing the expectations of local I.T. management against the performance of Project Managers that are currently operating within PMOs, it is clear that organisations within the NMM area are in need of PMO’s and would certainly benefit from their establishment.
- Full Text:
- Date Issued: 2007
Factors impacting the design of a mobile application for soil management: a case study of the Eastern Cape crops
- Authors: Botha, Stephan
- Date: 2019
- Subjects: Mobile soil management application
- Language: English
- Type: Thesis , Masters , MIT
- Identifier: http://hdl.handle.net/10948/44581 , vital:38127
- Description: Some of the biggest challenges the global community has to face are the ever-dwindling levels of freshwater resources, the drastic impact of the greenhouse gases on the global climate and the loss of non-renewable fertile soil. South African agriculture contributes a total of 12.7% to the overall South African GDP (gross domestic product). Only a small portion of the South African soil is considered as being able to grow healthy and nutritious crops. The world of information communication technology (ICT) is extremely vast and growing daily with newly created tools, to accommodate the needs of a specific sector, such as agriculture. As the ICT-based agricultural solutions increase and improve, the uptake of these solutions within the South African agricultural sector becomes even smaller. The reasons for the low uptake of mobile soil management solutions for crop growing farmers are unknown, due to limited research conducted. The identified problem was a lack of understanding of the way mobile technologies can be designed to adequately support farmers to correctly manage their soil to produce the best possible crops. The primary objective of this research study was to identify factors, which may have a significant impact on the design of a mobile soil management application for crop farmers in the Eastern Cape (South Africa). The secondary objectives were as follows: (i) to determine what soil management is and which aspects are required to implement soil management effectively; (ii) to identify possible mobile technologies suitable to act as an effective support structure for a mobile soil management application; and (iii) to identify which user experience guidelines are key for the development of an effective mobile soil management solution and to compile a user experience guideline for an effective mobile soil management solution. Achieving these objectives, resulted in a better understanding of the identified problem. The problem was addressed by conducting a thorough literature review and a case study to better grasp the different aspects of the identified problem. Quantitative data was collected by conducting a user interface evaluation. Qualitative data were also gathered by means of a field test using the mobile soil management application. The field test was done in conjunction with a heuristic evaluation, completed by the participants. Data triangulation was used to compare the results of the gathered data. The results from the data triangulation were used to confirm the factors, which made the most significant impact on the success of the soil management application. These confirmed design factors were used to produce a list of guidelines to improve the design of future mobile ICT soil management applications.
- Full Text:
- Date Issued: 2019
- Authors: Botha, Stephan
- Date: 2019
- Subjects: Mobile soil management application
- Language: English
- Type: Thesis , Masters , MIT
- Identifier: http://hdl.handle.net/10948/44581 , vital:38127
- Description: Some of the biggest challenges the global community has to face are the ever-dwindling levels of freshwater resources, the drastic impact of the greenhouse gases on the global climate and the loss of non-renewable fertile soil. South African agriculture contributes a total of 12.7% to the overall South African GDP (gross domestic product). Only a small portion of the South African soil is considered as being able to grow healthy and nutritious crops. The world of information communication technology (ICT) is extremely vast and growing daily with newly created tools, to accommodate the needs of a specific sector, such as agriculture. As the ICT-based agricultural solutions increase and improve, the uptake of these solutions within the South African agricultural sector becomes even smaller. The reasons for the low uptake of mobile soil management solutions for crop growing farmers are unknown, due to limited research conducted. The identified problem was a lack of understanding of the way mobile technologies can be designed to adequately support farmers to correctly manage their soil to produce the best possible crops. The primary objective of this research study was to identify factors, which may have a significant impact on the design of a mobile soil management application for crop farmers in the Eastern Cape (South Africa). The secondary objectives were as follows: (i) to determine what soil management is and which aspects are required to implement soil management effectively; (ii) to identify possible mobile technologies suitable to act as an effective support structure for a mobile soil management application; and (iii) to identify which user experience guidelines are key for the development of an effective mobile soil management solution and to compile a user experience guideline for an effective mobile soil management solution. Achieving these objectives, resulted in a better understanding of the identified problem. The problem was addressed by conducting a thorough literature review and a case study to better grasp the different aspects of the identified problem. Quantitative data was collected by conducting a user interface evaluation. Qualitative data were also gathered by means of a field test using the mobile soil management application. The field test was done in conjunction with a heuristic evaluation, completed by the participants. Data triangulation was used to compare the results of the gathered data. The results from the data triangulation were used to confirm the factors, which made the most significant impact on the success of the soil management application. These confirmed design factors were used to produce a list of guidelines to improve the design of future mobile ICT soil management applications.
- Full Text:
- Date Issued: 2019
Ultra-high precision manufacturing
- Authors: Abou-El-Hossein, Khaled
- Subjects: Machining , Diamond turning , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/20878 , vital:29410
- Description: One of the engineering areas focusing on the research and development of highvalue components and manufacturing technologies is precision engineering. Precision engineering represents a variety of engineering and science disciplines ranging from areas such as mechanical, electronics and industrial engineering to chemistry, physics, optics and materials science. This paper aims at familiarising the reader with the recent advances in ultra-high precision manufacturing technologies and their applications for the production of various critical components employed in different sectors of the industry. In this paper, the principles of ultra-high precision manufacturing will be discussed followed by examples of its use in various industrial applications. The status of ultra-high precision manufacturing in terms of current research issues and future trends will be discussed. In addition, research activities and projects in the area of precision manufacturing that are currently conducted at the NMMU will be also highlighted. Finally, the author looks forward to presenting herewith comprehensive information that could be useful to the reader and easy to understand by the bigger NMMU’s community.
- Full Text:
- Authors: Abou-El-Hossein, Khaled
- Subjects: Machining , Diamond turning , f-sa
- Language: English
- Type: text , Lectures
- Identifier: http://hdl.handle.net/10948/20878 , vital:29410
- Description: One of the engineering areas focusing on the research and development of highvalue components and manufacturing technologies is precision engineering. Precision engineering represents a variety of engineering and science disciplines ranging from areas such as mechanical, electronics and industrial engineering to chemistry, physics, optics and materials science. This paper aims at familiarising the reader with the recent advances in ultra-high precision manufacturing technologies and their applications for the production of various critical components employed in different sectors of the industry. In this paper, the principles of ultra-high precision manufacturing will be discussed followed by examples of its use in various industrial applications. The status of ultra-high precision manufacturing in terms of current research issues and future trends will be discussed. In addition, research activities and projects in the area of precision manufacturing that are currently conducted at the NMMU will be also highlighted. Finally, the author looks forward to presenting herewith comprehensive information that could be useful to the reader and easy to understand by the bigger NMMU’s community.
- Full Text:
Towards a user centric model for identity and access management within the online environment
- Authors: Deas, Matthew Burns
- Date: 2008
- Subjects: Computers -- Access control , Computer networks -- Security measures
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9780 , http://hdl.handle.net/10948/775 , Computers -- Access control , Computer networks -- Security measures
- Description: Today, one is expected to remember multiple user names and passwords for different domains when one wants to access on the Internet. Identity management seeks to solve this problem through creating a digital identity that is exchangeable across organisational boundaries. Through the setup of collaboration agreements between multiple domains, users can easily switch across domains without being required to sign in again. However, use of this technology comes with risks of user identity and personal information being compromised. Criminals make use of spoofed websites and social engineering techniques to gain illegal access to user information. Due to this, the need for users to be protected from online threats has increased. Two processes are required to protect the user login information at the time of sign-on. Firstly, user’s information must be protected at the time of sign-on, and secondly, a simple method for the identification of the website is required by the user. This treatise looks at the process for identifying and verifying user information, and how the user can verify the system at sign-in. Three models for identity management are analysed, namely the Microsoft .NET Passport, Liberty Alliance Federated Identity for Single Sign-on and the Mozilla TrustBar for system authentication.
- Full Text:
- Date Issued: 2008
- Authors: Deas, Matthew Burns
- Date: 2008
- Subjects: Computers -- Access control , Computer networks -- Security measures
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9780 , http://hdl.handle.net/10948/775 , Computers -- Access control , Computer networks -- Security measures
- Description: Today, one is expected to remember multiple user names and passwords for different domains when one wants to access on the Internet. Identity management seeks to solve this problem through creating a digital identity that is exchangeable across organisational boundaries. Through the setup of collaboration agreements between multiple domains, users can easily switch across domains without being required to sign in again. However, use of this technology comes with risks of user identity and personal information being compromised. Criminals make use of spoofed websites and social engineering techniques to gain illegal access to user information. Due to this, the need for users to be protected from online threats has increased. Two processes are required to protect the user login information at the time of sign-on. Firstly, user’s information must be protected at the time of sign-on, and secondly, a simple method for the identification of the website is required by the user. This treatise looks at the process for identifying and verifying user information, and how the user can verify the system at sign-in. Three models for identity management are analysed, namely the Microsoft .NET Passport, Liberty Alliance Federated Identity for Single Sign-on and the Mozilla TrustBar for system authentication.
- Full Text:
- Date Issued: 2008
Development of a creep sample retrieval technique and friction weld site repair procedure
- Authors: Wedderburn, Ian Norman
- Date: 2013
- Subjects: Friction welding
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9635 , http://hdl.handle.net/10948/d1020116
- Description: The remnant life monitoring of creep loaded high temperature and pressure components in power stations is critical to ensuring their safe and cost effective operation as failures can have severe consequences. Effective creep life condition monitoring allows for optimising component life predictions and subsequent plant maintenance decisions. In South Africa many power generation stations have been in operation well beyond their 30 year design service life, as such knowledge of the remnant creep life of high temperature and pressure components, such as steam pipelines, becomes of utmost importance. Techniques for the remnant creep life assessments of critical high temperature and pressure components must therefore be as effective as possible. The common and well accepted in-situ inspection technique for assessing creep damage in steam pipes is by the metallographic replication technique. The technique is however limited to the outer surface of the pipe, without information on damage within the wall. This research will illustrate a means of obtaining a sample for creep life analysis with depth through the wall of a pipe, as wells as an alternative technique for the repair of the sample retrieval site. A sample retrieval technique was developed that would retrieve a small diameter cylindrical sample from a cored blind hole for creep analysis by visual creep void assessment or by the small punch creep test. The small punch creep test requires only a small diameter thin disc of material for testing for which its results are comparable with conventional uniaxial creep testing which requires a much larger sample of material. The smaller sample requirement of the small punch creep test therefore allows for a vastly reduced invasive sample retrieval operation and consequently smaller repair size area. Also the fact that the sample is retrieved from a blind hole is advantageous since the pipe wall is not penetrated which would require full plant shutdown. A friction welding technique was identified as an alternative to traditional arc fusion welding for the repair of the sample retrieval site, this technique being the Friction Hydro Pillar Processing technique. Friction Hydro Pillar Processing is a solid-state welding technique and as such has a number of inherent benefits over arc fusion welding as the weld is performed below the melting temperature of the material. From a process point of view Friction Hydro Pillar Processing is ideally suited for automation, has virtually no fumes generated, minimal distortion is experienced and no spatter has to be removed afterwards. The technique has yet to see industrial application and as such development of suitable process parameters was undertaken. Finally, to apply the sample retrieval and repair operations in-situ to a steam pipe in a power plant suitable equipment was developed. Existing friction welding equipment is generally bulky workshop based equipment and is unsuitable for on-site work due to its size and weight. Therefore development of dedicated equipment was required to enable Friction Hydro Pillar Processing to be applied to steam pipes within a power plant environment.
- Full Text:
- Date Issued: 2013
- Authors: Wedderburn, Ian Norman
- Date: 2013
- Subjects: Friction welding
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9635 , http://hdl.handle.net/10948/d1020116
- Description: The remnant life monitoring of creep loaded high temperature and pressure components in power stations is critical to ensuring their safe and cost effective operation as failures can have severe consequences. Effective creep life condition monitoring allows for optimising component life predictions and subsequent plant maintenance decisions. In South Africa many power generation stations have been in operation well beyond their 30 year design service life, as such knowledge of the remnant creep life of high temperature and pressure components, such as steam pipelines, becomes of utmost importance. Techniques for the remnant creep life assessments of critical high temperature and pressure components must therefore be as effective as possible. The common and well accepted in-situ inspection technique for assessing creep damage in steam pipes is by the metallographic replication technique. The technique is however limited to the outer surface of the pipe, without information on damage within the wall. This research will illustrate a means of obtaining a sample for creep life analysis with depth through the wall of a pipe, as wells as an alternative technique for the repair of the sample retrieval site. A sample retrieval technique was developed that would retrieve a small diameter cylindrical sample from a cored blind hole for creep analysis by visual creep void assessment or by the small punch creep test. The small punch creep test requires only a small diameter thin disc of material for testing for which its results are comparable with conventional uniaxial creep testing which requires a much larger sample of material. The smaller sample requirement of the small punch creep test therefore allows for a vastly reduced invasive sample retrieval operation and consequently smaller repair size area. Also the fact that the sample is retrieved from a blind hole is advantageous since the pipe wall is not penetrated which would require full plant shutdown. A friction welding technique was identified as an alternative to traditional arc fusion welding for the repair of the sample retrieval site, this technique being the Friction Hydro Pillar Processing technique. Friction Hydro Pillar Processing is a solid-state welding technique and as such has a number of inherent benefits over arc fusion welding as the weld is performed below the melting temperature of the material. From a process point of view Friction Hydro Pillar Processing is ideally suited for automation, has virtually no fumes generated, minimal distortion is experienced and no spatter has to be removed afterwards. The technique has yet to see industrial application and as such development of suitable process parameters was undertaken. Finally, to apply the sample retrieval and repair operations in-situ to a steam pipe in a power plant suitable equipment was developed. Existing friction welding equipment is generally bulky workshop based equipment and is unsuitable for on-site work due to its size and weight. Therefore development of dedicated equipment was required to enable Friction Hydro Pillar Processing to be applied to steam pipes within a power plant environment.
- Full Text:
- Date Issued: 2013
A sustainable water quality framework for South Africa towards 2050
- Authors: Osmond, Christopher John
- Date: 2015
- Subjects: Construction industry -- South Africa , Sustainable development -- South Africa , Water resources development -- South Africa , Water quality management -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/3255 , vital:20417
- Description: There are a wide range of issues that stem from inadequate access to, and the unsustainable management of water resources, which can lead to ecological and human crises (Gleik, 1998: 571). With the increasing demand for clean water for drinking and sanitation, coupled with population growth, aging infrastructure, and climate change, many countries face a complex set of threats when dealing with their water resources and the management thereof (Environmental Protection Agency, 2012: 4). South Africa‟s challenges are no different, if current trends in water management continue and government does not intervene with what has been an unequal society even in terms of the division of water, it will continue to lose ground in its development and sustaining of water resources (Ukwandu, 2009: 24 - 30). “The objective of managing the quantity, quality and reliability of the nation‟s water resources is to achieve optimum, long-term, environmentally sustainable social and economic benefit for society from their use.” (Principle 7 of the National Water Policy, Department of Water Affairs and Forestry, 1997: 20). The primary objective of this research is to develop a framework for water management and sustainable development by utilising a Causal Layered Analysis (CLA) to develop strategies for innovation in South Africa towards 2050. New rules and regulations have been adopted by local municipal divisions in South Africa to promote sustainable, environmentally friendly buildings and methods. It is therefore the aim of the research to establish ways in which water can be harvested and saved in a simple and innovative yet sustainable manner. The complexity of erecting structures has also increased with some sustainable measures in water management taking place, however the water issues in South Africa continue to grow and cause concern. Government therefore plays a pivotal role in ensuring that water is managed sustainably at not only harvesting and infrastructure level but also re-cycling level, where simple innovative strategies can be adopted. This paper further seeks to highlight the positive and negative impacts of implementing water management methods and strategies that can be adopted.
- Full Text:
- Date Issued: 2015
- Authors: Osmond, Christopher John
- Date: 2015
- Subjects: Construction industry -- South Africa , Sustainable development -- South Africa , Water resources development -- South Africa , Water quality management -- South Africa
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: http://hdl.handle.net/10948/3255 , vital:20417
- Description: There are a wide range of issues that stem from inadequate access to, and the unsustainable management of water resources, which can lead to ecological and human crises (Gleik, 1998: 571). With the increasing demand for clean water for drinking and sanitation, coupled with population growth, aging infrastructure, and climate change, many countries face a complex set of threats when dealing with their water resources and the management thereof (Environmental Protection Agency, 2012: 4). South Africa‟s challenges are no different, if current trends in water management continue and government does not intervene with what has been an unequal society even in terms of the division of water, it will continue to lose ground in its development and sustaining of water resources (Ukwandu, 2009: 24 - 30). “The objective of managing the quantity, quality and reliability of the nation‟s water resources is to achieve optimum, long-term, environmentally sustainable social and economic benefit for society from their use.” (Principle 7 of the National Water Policy, Department of Water Affairs and Forestry, 1997: 20). The primary objective of this research is to develop a framework for water management and sustainable development by utilising a Causal Layered Analysis (CLA) to develop strategies for innovation in South Africa towards 2050. New rules and regulations have been adopted by local municipal divisions in South Africa to promote sustainable, environmentally friendly buildings and methods. It is therefore the aim of the research to establish ways in which water can be harvested and saved in a simple and innovative yet sustainable manner. The complexity of erecting structures has also increased with some sustainable measures in water management taking place, however the water issues in South Africa continue to grow and cause concern. Government therefore plays a pivotal role in ensuring that water is managed sustainably at not only harvesting and infrastructure level but also re-cycling level, where simple innovative strategies can be adopted. This paper further seeks to highlight the positive and negative impacts of implementing water management methods and strategies that can be adopted.
- Full Text:
- Date Issued: 2015
A framework for the integration of mobile technology into adventure sport for the purpose of increasing participant safety
- Authors: Mills, Craig John
- Date: 2018
- Subjects: Mobile communication systems , Health promotion -- Technological innovations Sports -- Technological innovations Cell phones -- Health aspects
- Language: English
- Type: Thesis , Masters , MIT
- Identifier: http://hdl.handle.net/10948/32099 , vital:31958
- Description: The sporting industry has seen incredible advancements with the use of information technology. Technology is used in the sporting industry for training, coaching and even as a deciding factor of a game result. There are certain sports which require individuals to venture into isolated environments, these sports have been termed adventure or extreme sports. Due to the extreme environmental factors that can occur with adventure sport, it is possible for an individual to experience an emergency situation. Emergency situations can occur at any time, and this is especially true in adventure sport. Adventure sport such as ocean and river kayaking require individuals to venture into isolated environments, where if an emergency situation occurs could result in an individual left stranded waiting for emergency rescue. Adventure sport participants and Event Organizers are aware of the dangers associated with this type of adventure sport, but there is currently no requirement to have a mobile technology device present during kayaking events. The main purpose of this dissertation was to evaluate the current use of mobile technology in adventure sport in the Eastern Cape province of South Africa. To accomplish this two literature reviews were conducted which identi_ed information on the two main themes which are adventure sport and mobile technology. To produce information from the ocean and river kayaking community an online questionnaire was distributed to several kayaking clubs in the Eastern Cape province of South Africa. This dissertation also presents a framework that proposes the use of mobile technology hardware and software by participants and event organisers in an attempt to increase the safety of events in this form of adventure sport. It is hoped that the framework for using mobile technology to increase the safety of adventure sport proposed in this research, may provide clear guidance for the achievement of a safer sporting experience for the participants of ocean and river kayaking.
- Full Text:
- Date Issued: 2018
- Authors: Mills, Craig John
- Date: 2018
- Subjects: Mobile communication systems , Health promotion -- Technological innovations Sports -- Technological innovations Cell phones -- Health aspects
- Language: English
- Type: Thesis , Masters , MIT
- Identifier: http://hdl.handle.net/10948/32099 , vital:31958
- Description: The sporting industry has seen incredible advancements with the use of information technology. Technology is used in the sporting industry for training, coaching and even as a deciding factor of a game result. There are certain sports which require individuals to venture into isolated environments, these sports have been termed adventure or extreme sports. Due to the extreme environmental factors that can occur with adventure sport, it is possible for an individual to experience an emergency situation. Emergency situations can occur at any time, and this is especially true in adventure sport. Adventure sport such as ocean and river kayaking require individuals to venture into isolated environments, where if an emergency situation occurs could result in an individual left stranded waiting for emergency rescue. Adventure sport participants and Event Organizers are aware of the dangers associated with this type of adventure sport, but there is currently no requirement to have a mobile technology device present during kayaking events. The main purpose of this dissertation was to evaluate the current use of mobile technology in adventure sport in the Eastern Cape province of South Africa. To accomplish this two literature reviews were conducted which identi_ed information on the two main themes which are adventure sport and mobile technology. To produce information from the ocean and river kayaking community an online questionnaire was distributed to several kayaking clubs in the Eastern Cape province of South Africa. This dissertation also presents a framework that proposes the use of mobile technology hardware and software by participants and event organisers in an attempt to increase the safety of events in this form of adventure sport. It is hoped that the framework for using mobile technology to increase the safety of adventure sport proposed in this research, may provide clear guidance for the achievement of a safer sporting experience for the participants of ocean and river kayaking.
- Full Text:
- Date Issued: 2018
A model for legal compliance in the South African banking sector : an information security perspective
- Maphakela, Madidimalo Rabbie
- Authors: Maphakela, Madidimalo Rabbie
- Date: 2008
- Subjects: Database security -- South Africa , Computer security -- South Africa , Computer networks -- Security measures -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9783 , http://hdl.handle.net/10948/725 , Database security -- South Africa , Computer security -- South Africa , Computer networks -- Security measures -- South Africa
- Description: In the past, many organisations used to keep their information on paper, which resulted in the loss of important information. In today’s knowledge era the information super-highway facilitates highly connected electronic environments where business applications can communicate on an intra- as well as inter-organizational level. As business expanded more into the cyber-world, so did the need to protect the information they have. Technology advances did not only bring benefits, it also increased the vulnerability of companies’ information. Information, the lifeblood of an organization, must be protected from threats such as hackers and fraud, amongst others. In the highly regulated financial sector, the protection of information is not only a best practice, but a legal obligation carrying penalties for non-compliance. From a positive aspect, organisations can identify security controls that can help them to secure their information, with the aid of legal sources. But organisations find themselves burdened by a burgeoning number of legal sources and requirements, which require vast resources and often become unmanageable. This research focuses on finding a solution for South African banks to comply with multiple legal sources, as seen from an information security perspective.
- Full Text:
- Date Issued: 2008
- Authors: Maphakela, Madidimalo Rabbie
- Date: 2008
- Subjects: Database security -- South Africa , Computer security -- South Africa , Computer networks -- Security measures -- South Africa
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9783 , http://hdl.handle.net/10948/725 , Database security -- South Africa , Computer security -- South Africa , Computer networks -- Security measures -- South Africa
- Description: In the past, many organisations used to keep their information on paper, which resulted in the loss of important information. In today’s knowledge era the information super-highway facilitates highly connected electronic environments where business applications can communicate on an intra- as well as inter-organizational level. As business expanded more into the cyber-world, so did the need to protect the information they have. Technology advances did not only bring benefits, it also increased the vulnerability of companies’ information. Information, the lifeblood of an organization, must be protected from threats such as hackers and fraud, amongst others. In the highly regulated financial sector, the protection of information is not only a best practice, but a legal obligation carrying penalties for non-compliance. From a positive aspect, organisations can identify security controls that can help them to secure their information, with the aid of legal sources. But organisations find themselves burdened by a burgeoning number of legal sources and requirements, which require vast resources and often become unmanageable. This research focuses on finding a solution for South African banks to comply with multiple legal sources, as seen from an information security perspective.
- Full Text:
- Date Issued: 2008
A strategy to make ICT accessible in rural Zambia: a case study of Macha
- Authors: Van Stam, Gertjan
- Date: 2013
- Subjects: Communication in rural development -- Zambia , Communication and technology -- Zambia
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9830
- Description: The problem discussed in this dissertation is to gather evidence of good practice and derive strategy for the development of ICT access in rural Zambia. Access to ICT services is important, also in rural areas of Africa. The challenges are many. There is a distinct void in tangible descriptions of the realities of ICT Access in rural areas or actionable guidelines for practitioners. This study involves a case study in the rural areas of Zambia. It does so through ethnography involving 10 years of observation of aspects of ICT access in rural Macha, Zambia. In this community, emerging from an articulated vision, ICT access in the form of the Internet arrived in 2004. Macha Works with its ICT unit LinkNet provides the basis for this interpretive approach from within the rural cultural setting. The purpose of the study is to benefit the local rural community, addressing the fundamentals of reality to add to the body of knowledge. The study involves cross cultural interaction and takes a trans-disciplinary view on science. It involves Participative Action Learning and Research aimed at recognising the complex adaptive systems while being aligned with the ethics of the rural African environment. Emphasis is on the needs of the community, rather than of the individual utilising empirical evidence. The good practices in Macha that inform strategy to make ICT accessible in rural areas are: engaging the community, building relationships; workforce development, unlocking productivity; thought leadership, establishing authority.
- Full Text:
- Date Issued: 2013
- Authors: Van Stam, Gertjan
- Date: 2013
- Subjects: Communication in rural development -- Zambia , Communication and technology -- Zambia
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9830
- Description: The problem discussed in this dissertation is to gather evidence of good practice and derive strategy for the development of ICT access in rural Zambia. Access to ICT services is important, also in rural areas of Africa. The challenges are many. There is a distinct void in tangible descriptions of the realities of ICT Access in rural areas or actionable guidelines for practitioners. This study involves a case study in the rural areas of Zambia. It does so through ethnography involving 10 years of observation of aspects of ICT access in rural Macha, Zambia. In this community, emerging from an articulated vision, ICT access in the form of the Internet arrived in 2004. Macha Works with its ICT unit LinkNet provides the basis for this interpretive approach from within the rural cultural setting. The purpose of the study is to benefit the local rural community, addressing the fundamentals of reality to add to the body of knowledge. The study involves cross cultural interaction and takes a trans-disciplinary view on science. It involves Participative Action Learning and Research aimed at recognising the complex adaptive systems while being aligned with the ethics of the rural African environment. Emphasis is on the needs of the community, rather than of the individual utilising empirical evidence. The good practices in Macha that inform strategy to make ICT accessible in rural areas are: engaging the community, building relationships; workforce development, unlocking productivity; thought leadership, establishing authority.
- Full Text:
- Date Issued: 2013
Building Information Modelling as a catalyst for an Integrated Construction Project Delivery culture in South Africa
- Authors: Froise, Timothy
- Date: 2014
- Subjects: Construction industry -- South Africa , Construction projects -- South Africa , Acculturation -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9716 , http://hdl.handle.net/10948/d1020872
- Description: The importance of technology in construction partnering agreements has been recognised as a vital part of integrated project delivery (IPD) philosophy. Building information modelling (BIM) is increasingly being used by consultants in South Africa during the design phase of construction projects. However, its use is generally not aimed at an integrated project delivery approach, but rather as a tool to generate documentation, as BIM is generally more efficient than traditional computer aided design (CAD) software. For the full benefits of BIM to be realised, a greater degree of acculturation is required between construction project organisations (CPOs). The current cultures of CPOs are separationist in nature and tend to inhibit acculturation within the industry. BIM provides a central source of information that can improve communications between CPOs and foster a collaborative culture. The research examines IPD and BIM in the South African context and investigates how BIM can contribute to IPD. A survey was conducted among registered contractors from the three top grades and architecture practices from two regions in South Africa. The survey was placed in context by a case study that analysed the use of BIM and the resulting communication network seen in a public works project using typical procurement methods. The associated problems with the current accepted paradigm are illuminated by the research.
- Full Text:
- Date Issued: 2014
- Authors: Froise, Timothy
- Date: 2014
- Subjects: Construction industry -- South Africa , Construction projects -- South Africa , Acculturation -- South Africa
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:9716 , http://hdl.handle.net/10948/d1020872
- Description: The importance of technology in construction partnering agreements has been recognised as a vital part of integrated project delivery (IPD) philosophy. Building information modelling (BIM) is increasingly being used by consultants in South Africa during the design phase of construction projects. However, its use is generally not aimed at an integrated project delivery approach, but rather as a tool to generate documentation, as BIM is generally more efficient than traditional computer aided design (CAD) software. For the full benefits of BIM to be realised, a greater degree of acculturation is required between construction project organisations (CPOs). The current cultures of CPOs are separationist in nature and tend to inhibit acculturation within the industry. BIM provides a central source of information that can improve communications between CPOs and foster a collaborative culture. The research examines IPD and BIM in the South African context and investigates how BIM can contribute to IPD. A survey was conducted among registered contractors from the three top grades and architecture practices from two regions in South Africa. The survey was placed in context by a case study that analysed the use of BIM and the resulting communication network seen in a public works project using typical procurement methods. The associated problems with the current accepted paradigm are illuminated by the research.
- Full Text:
- Date Issued: 2014
Cost and reward as motivating factors in distributed collaborative learning assignments : a grounded theory analasis
- Van Niekerk, Johanna Cornelia
- Authors: Van Niekerk, Johanna Cornelia
- Date: 2009
- Subjects: Group work in education -- South Africa , Team learning approach in education -- South Africa , Education -- Experimental methods
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9764 , http://hdl.handle.net/10948/1103 , Group work in education -- South Africa , Team learning approach in education -- South Africa , Education -- Experimental methods
- Description: The objective of this research study was to obtain a better understanding of the factors that affect lecturer and student participation in distributed collaborative learning assignments (DCLAs). A substantial number of courses worldwide have included DCLAs in their curricula in an attempt to teach students virtual communication and teaming skills, and to allow distributed students to learn course content collaboratively in a virtual environment. The execution and management of these assignments have proven to be more challenging that expected. Several attempts reported on in the literature had to be abandoned when cost exceeded the rewards for both lecturers and students. In a fouryear cyclical action research project carried out at the PETech (Port Elizabeth Technikon, currently part of the Nelson Mandela Metropolitan University, South Africa), ICT students at several of the PETech campuses were required to complete a DCLA in virtual teams. This project also had to be terminated when it was realised that virtual team learning was minimal and the time investment unacceptably high. For the research study reported on in this thesis the data collected during the four “preresearch” cycles and the experiences reported in the literature were analysed. The lessons learnt were applied to a new additional DCLA cycle which formed part of an ICT course, although this execution still showed room for improvement. A second additional cycle was then executed which had a high participation rate and was overwhelmingly labelled by the participating students as a valuable and enjoyable learning experience. Analysis of the factors affecting participation in DCLAs shows that they are numerous and tightly interlinked, and that each factor is able to take on a wide range of values. This complicates descriptive reporting as each of the DCLAs was unique with unique outcomes and would have to be reported as such in order to iii ABSTRACT iv gain an understanding of the factors. Hence, a level of abstraction was needed, which was accomplished by applying the traditional Glaserian grounded theory method to the data collected during the four “preresearch” and the two additional cycles, and from the literature on the topic. The outcome is a perceived costs and rewards (PCR) theory for participation in DCLAs. As participation is crucial for the learning experience of each student as well as his/her team members in an action learning environment, deciding on participation by continually calculating the costs versus rewards became the focal point of the theory. To the best of the author’s knowledge this research study makes a theoretical contribution to the existing body of ICT educational knowledge in the form of a perceived costs and rewards theory for DCLA participation and a practical contribution in that it provides a theory that can be used to explain, understand, interpret and predict participation in DCLAs. This research study provides guidance for future research in both of these areas.
- Full Text:
- Date Issued: 2009
- Authors: Van Niekerk, Johanna Cornelia
- Date: 2009
- Subjects: Group work in education -- South Africa , Team learning approach in education -- South Africa , Education -- Experimental methods
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: vital:9764 , http://hdl.handle.net/10948/1103 , Group work in education -- South Africa , Team learning approach in education -- South Africa , Education -- Experimental methods
- Description: The objective of this research study was to obtain a better understanding of the factors that affect lecturer and student participation in distributed collaborative learning assignments (DCLAs). A substantial number of courses worldwide have included DCLAs in their curricula in an attempt to teach students virtual communication and teaming skills, and to allow distributed students to learn course content collaboratively in a virtual environment. The execution and management of these assignments have proven to be more challenging that expected. Several attempts reported on in the literature had to be abandoned when cost exceeded the rewards for both lecturers and students. In a fouryear cyclical action research project carried out at the PETech (Port Elizabeth Technikon, currently part of the Nelson Mandela Metropolitan University, South Africa), ICT students at several of the PETech campuses were required to complete a DCLA in virtual teams. This project also had to be terminated when it was realised that virtual team learning was minimal and the time investment unacceptably high. For the research study reported on in this thesis the data collected during the four “preresearch” cycles and the experiences reported in the literature were analysed. The lessons learnt were applied to a new additional DCLA cycle which formed part of an ICT course, although this execution still showed room for improvement. A second additional cycle was then executed which had a high participation rate and was overwhelmingly labelled by the participating students as a valuable and enjoyable learning experience. Analysis of the factors affecting participation in DCLAs shows that they are numerous and tightly interlinked, and that each factor is able to take on a wide range of values. This complicates descriptive reporting as each of the DCLAs was unique with unique outcomes and would have to be reported as such in order to iii ABSTRACT iv gain an understanding of the factors. Hence, a level of abstraction was needed, which was accomplished by applying the traditional Glaserian grounded theory method to the data collected during the four “preresearch” and the two additional cycles, and from the literature on the topic. The outcome is a perceived costs and rewards (PCR) theory for participation in DCLAs. As participation is crucial for the learning experience of each student as well as his/her team members in an action learning environment, deciding on participation by continually calculating the costs versus rewards became the focal point of the theory. To the best of the author’s knowledge this research study makes a theoretical contribution to the existing body of ICT educational knowledge in the form of a perceived costs and rewards theory for DCLA participation and a practical contribution in that it provides a theory that can be used to explain, understand, interpret and predict participation in DCLAs. This research study provides guidance for future research in both of these areas.
- Full Text:
- Date Issued: 2009
Analysis of the reliability for the 132/66/22 KV distribution network within ESKOM’s Eastern Cape operating unit
- Authors: Pantshwa, Athini
- Date: 2017
- Subjects: Electric power distribution Electricity -- Supply -- Engineering , Smart power grids
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/19750 , vital:28953
- Description: A stable and reliable electrical power supply system is an inevitable pre-requisite for the technological and economic growth of any nation. Due to this, utilities must strive and ensure that the customer’s reliability requirements are met and that the regulators requirements are satisfied at the lowest possible cost. It is known fact around the world that 90% of the customer service interruptions are caused due to failure in distribution system. Therefore, it is worth considering reliability assessments as it provides an opportunity to incorporate the cost or losses incurred by the utilities customer as a result of power failure. This must be considered in the planning and operating practices. The system modelling and simulation study is carried out on one of the district’s distribution system which consists of 132 kV, 66 kV and 22 kV network in Aliwal North Sector ECOU. The reliability assessment is done on the 22, 66 and 132 kV system to assess the performance of the present system and also predictive reliability analysis for the future system considering load growth and system expansion. The alternative which gives low SAIDI, SAIFI and minimum breakeven costs is being assessed and considered. The reliability of 132 kV system could be further improved by constructing a new 132 kV line from a different source of supply and connecting with line coming from another district (reserve) at reasonable break even cost. The decision base could be further improved by having Aliwal North Sector context interruption cost. However, the historical data which may be used in Aliwal North Sector to acquire interruption costs from the customers are being proposed. The focus should be on improving the power quality on constrained networks first, then the reliability. Therefore for the Aliwal North power system network it is imperative that Eskom invest on the reliability of this network. This dissertation also analysed load reflected economic benefit versus performance expectations that should be optimized through achieving a balance between network performance (SAIDI) improvement, and total life cycle cost (to Eskom as well as the economy). Reliability analysis conducted in this dissertation used Aliwal North power system network as a case study; the results proved that the system is vulnerable to faults, planned and unplanned outages. Reliability evaluation studies were conducted on the system using DigSilent software in conjunction with FME. These two models gave accurate results with acceptable variance in most indices except for the ENS where the variance was quite significant. It can be concluded that DigSilent results are the most accurate results in all three reliability evaluation scenarios for the Aliwal North Power System, best interpretation being that of DigSilent.
- Full Text:
- Date Issued: 2017
- Authors: Pantshwa, Athini
- Date: 2017
- Subjects: Electric power distribution Electricity -- Supply -- Engineering , Smart power grids
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/19750 , vital:28953
- Description: A stable and reliable electrical power supply system is an inevitable pre-requisite for the technological and economic growth of any nation. Due to this, utilities must strive and ensure that the customer’s reliability requirements are met and that the regulators requirements are satisfied at the lowest possible cost. It is known fact around the world that 90% of the customer service interruptions are caused due to failure in distribution system. Therefore, it is worth considering reliability assessments as it provides an opportunity to incorporate the cost or losses incurred by the utilities customer as a result of power failure. This must be considered in the planning and operating practices. The system modelling and simulation study is carried out on one of the district’s distribution system which consists of 132 kV, 66 kV and 22 kV network in Aliwal North Sector ECOU. The reliability assessment is done on the 22, 66 and 132 kV system to assess the performance of the present system and also predictive reliability analysis for the future system considering load growth and system expansion. The alternative which gives low SAIDI, SAIFI and minimum breakeven costs is being assessed and considered. The reliability of 132 kV system could be further improved by constructing a new 132 kV line from a different source of supply and connecting with line coming from another district (reserve) at reasonable break even cost. The decision base could be further improved by having Aliwal North Sector context interruption cost. However, the historical data which may be used in Aliwal North Sector to acquire interruption costs from the customers are being proposed. The focus should be on improving the power quality on constrained networks first, then the reliability. Therefore for the Aliwal North power system network it is imperative that Eskom invest on the reliability of this network. This dissertation also analysed load reflected economic benefit versus performance expectations that should be optimized through achieving a balance between network performance (SAIDI) improvement, and total life cycle cost (to Eskom as well as the economy). Reliability analysis conducted in this dissertation used Aliwal North power system network as a case study; the results proved that the system is vulnerable to faults, planned and unplanned outages. Reliability evaluation studies were conducted on the system using DigSilent software in conjunction with FME. These two models gave accurate results with acceptable variance in most indices except for the ENS where the variance was quite significant. It can be concluded that DigSilent results are the most accurate results in all three reliability evaluation scenarios for the Aliwal North Power System, best interpretation being that of DigSilent.
- Full Text:
- Date Issued: 2017
Manufacturing as a reference for rethinking construction design management
- Authors: Sidloyi, Xabiso
- Date: 2008
- Subjects: Industrial design -- Management , Construction industry -- Management -- South Africa -- Eastern Cape , Architecture -- Management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9667 , http://hdl.handle.net/10948/766 , Industrial design -- Management , Construction industry -- Management -- South Africa -- Eastern Cape , Architecture -- Management
- Description: Design changes due to lack of constructability, cost overruns, delays and dissatisfied clients are but a few problems experienced in construction due to poor management of the design processes. Increased problems, challenges, demands and continuous criticism of the architectural profession has led to increased demand for research into the improvement of design processes. The aims of this research were to determine the adequacy of design management processes used by Eastern Cape (EC) architectural companies and compare these with the design management processes used in manufacturing in order to establish practices, theories, principles, technologies and deliverables that can be transferred from the manufacturing into the construction to improve efficiency of architectural design management. The quantitative research approach was implemented for this research, the questionnaire was designed to acquire primary, factual and attitudinal data from EC architectural companies and secondary data were acquired through a literature review. The results revealed that design management processes, continuous improvement philosophies, lean principles, and Information and Communication Technology (ICT) used by EC architectural companies are not similar to those used in manufacturing. Therefore EC architectural companies could increase their efficiency by adopting some of the design management processes, ICT, continuous improvement philosophies and lean principles originating from the manufacturing industry.
- Full Text:
- Date Issued: 2008
- Authors: Sidloyi, Xabiso
- Date: 2008
- Subjects: Industrial design -- Management , Construction industry -- Management -- South Africa -- Eastern Cape , Architecture -- Management
- Language: English
- Type: Thesis , Masters , MSc
- Identifier: vital:9667 , http://hdl.handle.net/10948/766 , Industrial design -- Management , Construction industry -- Management -- South Africa -- Eastern Cape , Architecture -- Management
- Description: Design changes due to lack of constructability, cost overruns, delays and dissatisfied clients are but a few problems experienced in construction due to poor management of the design processes. Increased problems, challenges, demands and continuous criticism of the architectural profession has led to increased demand for research into the improvement of design processes. The aims of this research were to determine the adequacy of design management processes used by Eastern Cape (EC) architectural companies and compare these with the design management processes used in manufacturing in order to establish practices, theories, principles, technologies and deliverables that can be transferred from the manufacturing into the construction to improve efficiency of architectural design management. The quantitative research approach was implemented for this research, the questionnaire was designed to acquire primary, factual and attitudinal data from EC architectural companies and secondary data were acquired through a literature review. The results revealed that design management processes, continuous improvement philosophies, lean principles, and Information and Communication Technology (ICT) used by EC architectural companies are not similar to those used in manufacturing. Therefore EC architectural companies could increase their efficiency by adopting some of the design management processes, ICT, continuous improvement philosophies and lean principles originating from the manufacturing industry.
- Full Text:
- Date Issued: 2008
Ultra-high precision machining of contact lens polymers
- Authors: Olufayo, Oluwole Ayodeji
- Date: 2015
- Subjects: Contact lenses , Polymers
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/3001 , vital:20385
- Description: Contact lens manufacture requires a high level of accuracy and surface integrity in the range of a few nanometres. Amidst numerous optical manufacturing techniques, single-point diamond turning is widely employed in the making of contact lenses due to its capability of producing optical surfaces of complex shapes and nanometric accuracy. For process optimisation, it is ideal to assess the effects of various conditions and also establish their relationships with the surface finish. Presently, there is little information available on the performance of single point diamond turning when machining contact lens polymers. Therefore, the research work undertaken herewith is aimed at testing known facts in contact lens diamond turning and investigating the performance of ultra-high precision manufacturing of contact lens polymers. Experimental tests were conducted on Roflufocon E, which is a commercially available contact lens polymer and on Precitech Nanoform Ultra-grind 250 precision machining. Tests were performed at varying cutting feeds, speed and depth of cut. Initial experimental tests investigated the influence of process factors affecting surface finish in the UHPM of lenses. The acquired data were statistically analysed using Response Surface Method (RSM) to create a model of the process. Subsequently, a model which uses Runge-Kutta’s fourth order non-linear finite series scheme was developed and adapted to deduce the force occurring at the tool tip. These forces were also statistically analysed and modelled to also predict the effects process factors have on cutting force. Further experimental tests were aimed at establishing the presence of the triboelectric wear phenomena occurring during polymer machining and identifying the most influential process factors. Results indicate that feed rate is a significant factor in the generation of high optical surface quality. In addition, the depth of cut was identified as a significant factor in the generation of low surface roughness in lenses. The influence some of these process factors had was notably linked to triboelectric effects. This tribological effect was generated from the continuous rubbing action of magnetised chips on the cutting tool. This further stresses the presence of high static charging during cutting. Moderately humid cutting conditions presented an adequate means for static charge control and displayed improved surface finishes. In all experimental tests, the feed rate was identified as the most significant factor within the range of cutting parameters employed. Hence, the results validated the fact that feed rate had a high influence in polymer machining. The work also established the relationship on how surface roughness of an optical lens responded to monitoring signals and parameters such as force, feed, speed and depth of cut during machining and it generated models for prediction of surface finishes and appropriate selection of parameters. Furthermore, the study provides a molecular simulation analysis for validating observed conditions occurring at the nanometric scale in polymer machining. This is novel in molecular polymer modelling. The outcome of this research has contributed significantly to the body of knowledge and has provided basic information in the area of precision manufacturing of optical components of high surface integrity such as contact lenses. The application of the research findings presented here cuts across various fields such as medicine, semi-conductors, aerospace, defence, telecom, lasers, instrumentation and life sciences.
- Full Text:
- Date Issued: 2015
- Authors: Olufayo, Oluwole Ayodeji
- Date: 2015
- Subjects: Contact lenses , Polymers
- Language: English
- Type: Thesis , Doctoral , DPhil
- Identifier: http://hdl.handle.net/10948/3001 , vital:20385
- Description: Contact lens manufacture requires a high level of accuracy and surface integrity in the range of a few nanometres. Amidst numerous optical manufacturing techniques, single-point diamond turning is widely employed in the making of contact lenses due to its capability of producing optical surfaces of complex shapes and nanometric accuracy. For process optimisation, it is ideal to assess the effects of various conditions and also establish their relationships with the surface finish. Presently, there is little information available on the performance of single point diamond turning when machining contact lens polymers. Therefore, the research work undertaken herewith is aimed at testing known facts in contact lens diamond turning and investigating the performance of ultra-high precision manufacturing of contact lens polymers. Experimental tests were conducted on Roflufocon E, which is a commercially available contact lens polymer and on Precitech Nanoform Ultra-grind 250 precision machining. Tests were performed at varying cutting feeds, speed and depth of cut. Initial experimental tests investigated the influence of process factors affecting surface finish in the UHPM of lenses. The acquired data were statistically analysed using Response Surface Method (RSM) to create a model of the process. Subsequently, a model which uses Runge-Kutta’s fourth order non-linear finite series scheme was developed and adapted to deduce the force occurring at the tool tip. These forces were also statistically analysed and modelled to also predict the effects process factors have on cutting force. Further experimental tests were aimed at establishing the presence of the triboelectric wear phenomena occurring during polymer machining and identifying the most influential process factors. Results indicate that feed rate is a significant factor in the generation of high optical surface quality. In addition, the depth of cut was identified as a significant factor in the generation of low surface roughness in lenses. The influence some of these process factors had was notably linked to triboelectric effects. This tribological effect was generated from the continuous rubbing action of magnetised chips on the cutting tool. This further stresses the presence of high static charging during cutting. Moderately humid cutting conditions presented an adequate means for static charge control and displayed improved surface finishes. In all experimental tests, the feed rate was identified as the most significant factor within the range of cutting parameters employed. Hence, the results validated the fact that feed rate had a high influence in polymer machining. The work also established the relationship on how surface roughness of an optical lens responded to monitoring signals and parameters such as force, feed, speed and depth of cut during machining and it generated models for prediction of surface finishes and appropriate selection of parameters. Furthermore, the study provides a molecular simulation analysis for validating observed conditions occurring at the nanometric scale in polymer machining. This is novel in molecular polymer modelling. The outcome of this research has contributed significantly to the body of knowledge and has provided basic information in the area of precision manufacturing of optical components of high surface integrity such as contact lenses. The application of the research findings presented here cuts across various fields such as medicine, semi-conductors, aerospace, defence, telecom, lasers, instrumentation and life sciences.
- Full Text:
- Date Issued: 2015
Precooling strategies for passenger vehicles
- Wachsmuth, Carsten Ulrich Harro
- Authors: Wachsmuth, Carsten Ulrich Harro
- Date: 2009
- Subjects: Automobiles -- Air conditioning , Air conditioning
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9643 , http://hdl.handle.net/10948/930 , Automobiles -- Air conditioning , Air conditioning
- Description: By ventilating the vehicle’s interior during a soak, the peak cooling load is reduced and therefore the air-conditioning needs less power. This in turn translates to a smaller air-conditioning unit which would consume less power, be lighter and more compact. This solar driven ventilation of the vehicle’s interior during a soak is defined as precooling. During this project the best precooling strategy for passenger vehicles was found by investigating and testing different precooling strategies and evaluating them according to their thermodynamic performance, their potential implementation and their influence on the required cooling performance of the airconditioning cycle. The best performances were achieved by strategies with a high air flow rate and a relatively low air inlet temperature. Two categories of precooling strategies were examined: natural convection and forced convection strategies. Openings in the vehicle’s body that fit to all strategies had to be found; with a big potential concerning their thermodynamic performance and other aspects like prevention against water penetration. The best investigated precooling strategies proved to be the one which used the design outlet as an inlet and the opening of the HVAC as an outlet. With these openings a good air flow through the whole cabin can be guaranteed. In addition to that the strategy only uses existing openings of the body which prevent against water penetration. The required installation space for this strategy already exists and can be considered for the package of next generation vehicles.
- Full Text:
- Date Issued: 2009
- Authors: Wachsmuth, Carsten Ulrich Harro
- Date: 2009
- Subjects: Automobiles -- Air conditioning , Air conditioning
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: vital:9643 , http://hdl.handle.net/10948/930 , Automobiles -- Air conditioning , Air conditioning
- Description: By ventilating the vehicle’s interior during a soak, the peak cooling load is reduced and therefore the air-conditioning needs less power. This in turn translates to a smaller air-conditioning unit which would consume less power, be lighter and more compact. This solar driven ventilation of the vehicle’s interior during a soak is defined as precooling. During this project the best precooling strategy for passenger vehicles was found by investigating and testing different precooling strategies and evaluating them according to their thermodynamic performance, their potential implementation and their influence on the required cooling performance of the airconditioning cycle. The best performances were achieved by strategies with a high air flow rate and a relatively low air inlet temperature. Two categories of precooling strategies were examined: natural convection and forced convection strategies. Openings in the vehicle’s body that fit to all strategies had to be found; with a big potential concerning their thermodynamic performance and other aspects like prevention against water penetration. The best investigated precooling strategies proved to be the one which used the design outlet as an inlet and the opening of the HVAC as an outlet. With these openings a good air flow through the whole cabin can be guaranteed. In addition to that the strategy only uses existing openings of the body which prevent against water penetration. The required installation space for this strategy already exists and can be considered for the package of next generation vehicles.
- Full Text:
- Date Issued: 2009
Application of the theory of critical distance technique to predict fracture toughness in friction stir welded Ti-6Al-4V sheet
- Authors: Rall, William Henry
- Date: 2017
- Subjects: Friction stir welding Fracture mechanics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/20351 , vital:29266
- Description: With modern day socioeconomic pressures to deliver more cost effective, higher performance and energy efficient mechanisms and structures, light weight design is coming more to the forefront of design methodologies. These methodologies need to apply lightweight materials in unison with a defect tolerant design strategy. Titanium is certainly not a new material and was used in large quantities in the 1960’s and ‘70s, but mostly in military applications. The main drawback of this material was cost, however due to current design needs as mentioned the consumption of the material is rising rapidly. Friction stir welding is by no means a new technique anymore, however, relatively speaking it is still in its infancy when compared to other traditional welding techniques. It has been applied mostly to low melting temperature metals, more specifically aluminium; however, its application to higher melting temperatures has started to enjoy more attention over the last few years. The lower temperatures at which the weld occurs, when compared to conventional processes, is the main reason for applying this technique to materials melting at a higher temperature such as titanium. Fracture mechanics allows modern-day designers and maintenance engineers to operate structures with an inherent flaw. These flaws may be due to geometric features of the design; fabrication defects or defects such as cracks that have developed over time within an operational structure. Fracture mechanics has evolved significantly since Griffith first proposed it in the early 20th century. The application of the method is often complex and determining the material properties for fracture resistance can be problematic and costly. Many techniques have been proposed over time to simplify the application of this method and one of these techniques would be the theory of critical distance. Since the technique is relatively new and has mostly been applied to more brittle materials, this study aimed not only to apply this technique to a more ductile material but additionally to one that is classified as a sheet material. The initial tests of this study investigated if a common convergent point could be determined by using three notches varying in size. The technique does not have a standard that governs its application. The initial tests did not yield a common intersecting point thus a second study was applied to see if sample width would influence the results. The results from the study indicated that wider samples seemed to yield similar apparent fracture toughness results, however a common convergence point could still not be established. This prompted a more in-depth study which involved various sample widths coupled with varying notch depths. Sharper notches were also applied and samples with controlled cracks were also tested. The results clearly showed that as the plastic zone size increases in relation to the ligament length of the sample, the critical distance becomes larger. The results also suggested that it would perhaps be best to use sample sizes with notches which allow fracture of the sample before the nett section stress reaches the material’s yield strength. The final tests involved testing the friction stir welded material. Various other studies were also done to corroborate the fracture toughness results. The stress relieved samples showed a reduction in the fracture toughness due to possible precipitation hardening during the stress relieving heat treatment process. The welded material showed an increase in the apparent fracture toughness when compared to the parent plate. The results indicate that residual stresses have an influence on the fracture toughness. In terms of the critical distance, it would appear that the value stays unchanged from the parent plate to the welded material; however, what is significant was that the value seemed to stay more or less constant as long as the nett section stress of the notched samples stayed below the yield stress of the material.
- Full Text:
- Date Issued: 2017
- Authors: Rall, William Henry
- Date: 2017
- Subjects: Friction stir welding Fracture mechanics
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: http://hdl.handle.net/10948/20351 , vital:29266
- Description: With modern day socioeconomic pressures to deliver more cost effective, higher performance and energy efficient mechanisms and structures, light weight design is coming more to the forefront of design methodologies. These methodologies need to apply lightweight materials in unison with a defect tolerant design strategy. Titanium is certainly not a new material and was used in large quantities in the 1960’s and ‘70s, but mostly in military applications. The main drawback of this material was cost, however due to current design needs as mentioned the consumption of the material is rising rapidly. Friction stir welding is by no means a new technique anymore, however, relatively speaking it is still in its infancy when compared to other traditional welding techniques. It has been applied mostly to low melting temperature metals, more specifically aluminium; however, its application to higher melting temperatures has started to enjoy more attention over the last few years. The lower temperatures at which the weld occurs, when compared to conventional processes, is the main reason for applying this technique to materials melting at a higher temperature such as titanium. Fracture mechanics allows modern-day designers and maintenance engineers to operate structures with an inherent flaw. These flaws may be due to geometric features of the design; fabrication defects or defects such as cracks that have developed over time within an operational structure. Fracture mechanics has evolved significantly since Griffith first proposed it in the early 20th century. The application of the method is often complex and determining the material properties for fracture resistance can be problematic and costly. Many techniques have been proposed over time to simplify the application of this method and one of these techniques would be the theory of critical distance. Since the technique is relatively new and has mostly been applied to more brittle materials, this study aimed not only to apply this technique to a more ductile material but additionally to one that is classified as a sheet material. The initial tests of this study investigated if a common convergent point could be determined by using three notches varying in size. The technique does not have a standard that governs its application. The initial tests did not yield a common intersecting point thus a second study was applied to see if sample width would influence the results. The results from the study indicated that wider samples seemed to yield similar apparent fracture toughness results, however a common convergence point could still not be established. This prompted a more in-depth study which involved various sample widths coupled with varying notch depths. Sharper notches were also applied and samples with controlled cracks were also tested. The results clearly showed that as the plastic zone size increases in relation to the ligament length of the sample, the critical distance becomes larger. The results also suggested that it would perhaps be best to use sample sizes with notches which allow fracture of the sample before the nett section stress reaches the material’s yield strength. The final tests involved testing the friction stir welded material. Various other studies were also done to corroborate the fracture toughness results. The stress relieved samples showed a reduction in the fracture toughness due to possible precipitation hardening during the stress relieving heat treatment process. The welded material showed an increase in the apparent fracture toughness when compared to the parent plate. The results indicate that residual stresses have an influence on the fracture toughness. In terms of the critical distance, it would appear that the value stays unchanged from the parent plate to the welded material; however, what is significant was that the value seemed to stay more or less constant as long as the nett section stress of the notched samples stayed below the yield stress of the material.
- Full Text:
- Date Issued: 2017
The effects of shot peening on low cycle fatigue life of 7075-T6 aluminium alloy round bar
- Authors: Peters, Donald Michael Dirk
- Date: 2014
- Subjects: Shot peening , Aluminum alloys -- Fatigue , Metals -- Fatigue
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/2929 , vital:20364
- Description: The aim in this dissertation was to improve our understanding of the effectiveness of shot peening in prolonging fatigue life, of 7075-T6 Aluminium Alloy round bar, taking into consideration surface residual stress, microstructural and micro-hardness parameters. Three point bending, high stress, moderately low cycle, fatigue tests were conducted to study the effects of shot peening and associated surface residual compressive stresses on fatigue life. The influence of shot peening on the microstructure was explored, including the application of mechanical small plastic straining and surface skimming, to vary the surface residual compressive stresses and induce strain hardening. Tests were performed to measure residual stress-depth distribution, plastic straining, micro-hardness, and the microstructure analysed on scanning electron microscopy (SEM) fractographs. The Juvinall and Marshek life prediction model was used in conjunction with the Gerber equation for non-zero mean stress applications to generate a proposed life prediction model for this material which is user-friendly. The proposed life prediction model has a linear equation format with the flexibility to conservatively accommodate most of the various types, and combinations, of treatments applied in this research by the use of customised constants. The results show that there was good correlation between actual and predicted fatigue life as well as useful insights into the role of the microstructure in explaining fatigue life behaviour.
- Full Text:
- Date Issued: 2014
- Authors: Peters, Donald Michael Dirk
- Date: 2014
- Subjects: Shot peening , Aluminum alloys -- Fatigue , Metals -- Fatigue
- Language: English
- Type: Thesis , Masters , MTech
- Identifier: http://hdl.handle.net/10948/2929 , vital:20364
- Description: The aim in this dissertation was to improve our understanding of the effectiveness of shot peening in prolonging fatigue life, of 7075-T6 Aluminium Alloy round bar, taking into consideration surface residual stress, microstructural and micro-hardness parameters. Three point bending, high stress, moderately low cycle, fatigue tests were conducted to study the effects of shot peening and associated surface residual compressive stresses on fatigue life. The influence of shot peening on the microstructure was explored, including the application of mechanical small plastic straining and surface skimming, to vary the surface residual compressive stresses and induce strain hardening. Tests were performed to measure residual stress-depth distribution, plastic straining, micro-hardness, and the microstructure analysed on scanning electron microscopy (SEM) fractographs. The Juvinall and Marshek life prediction model was used in conjunction with the Gerber equation for non-zero mean stress applications to generate a proposed life prediction model for this material which is user-friendly. The proposed life prediction model has a linear equation format with the flexibility to conservatively accommodate most of the various types, and combinations, of treatments applied in this research by the use of customised constants. The results show that there was good correlation between actual and predicted fatigue life as well as useful insights into the role of the microstructure in explaining fatigue life behaviour.
- Full Text:
- Date Issued: 2014