Partnerships and parents–relationships in tutorial programmes
- Layton, Delia M, McKenna, Sioux
- Authors: Layton, Delia M , McKenna, Sioux
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66699 , vital:28983 , ISSN 1469-8366 , https://doi.org/10.1080/07294360.2015.1087471
- Description: The tutorial system is considered to be a useful pedagogical intervention to improve student retention, particularly in the context of a first-year student’s experience of entering university. For these novice students to achieve academic success, it is important that they are given access to the subject-specific knowledge and practices in their different disciplines, that is, that they acquire ‘epistemological access’. A recent study of the tutorial system in a South African university (Layton, D.M. [2013]. A social realist account of the tutorial system at the University of Johannesburg (Unpublished doctoral dissertation). Rhodes University, Grahamstown), sought to discover to what extent tutorials were discursively constructed as being about the enablement of epistemological access. This paper focuses on two discourses that emerged from the study – the parent discourse and the partnership discourse. Both discourses were concerned with relationships between key stakeholders in the tutorial programme. Given that tutorials are considered to be spaces in which more intimate learning can take place than in the anonymous environment of the large lecture hall, an interrogation of the relationships fostered in tutorials is important. The parent discourse, in which students were positioned as ‘kids’ needing care, was supportive of new students but ran the risk of being patronising and reductionist. The partnerships discourse, in which tutors and academics were seen to be working together towards the common goal of student success, was seen to be enabling of epistemological access. But it required a commitment to teaching endeavours that was in tension with the institutional focus on research. Through a social realist analysis of the two discourses constructing relationships in the tutorial system, we conclude that these discourses have the power to both constrain and enable the extent to which the tutorial system can be a site of epistemological access.
- Full Text: false
- Date Issued: 2016
- Authors: Layton, Delia M , McKenna, Sioux
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66699 , vital:28983 , ISSN 1469-8366 , https://doi.org/10.1080/07294360.2015.1087471
- Description: The tutorial system is considered to be a useful pedagogical intervention to improve student retention, particularly in the context of a first-year student’s experience of entering university. For these novice students to achieve academic success, it is important that they are given access to the subject-specific knowledge and practices in their different disciplines, that is, that they acquire ‘epistemological access’. A recent study of the tutorial system in a South African university (Layton, D.M. [2013]. A social realist account of the tutorial system at the University of Johannesburg (Unpublished doctoral dissertation). Rhodes University, Grahamstown), sought to discover to what extent tutorials were discursively constructed as being about the enablement of epistemological access. This paper focuses on two discourses that emerged from the study – the parent discourse and the partnership discourse. Both discourses were concerned with relationships between key stakeholders in the tutorial programme. Given that tutorials are considered to be spaces in which more intimate learning can take place than in the anonymous environment of the large lecture hall, an interrogation of the relationships fostered in tutorials is important. The parent discourse, in which students were positioned as ‘kids’ needing care, was supportive of new students but ran the risk of being patronising and reductionist. The partnerships discourse, in which tutors and academics were seen to be working together towards the common goal of student success, was seen to be enabling of epistemological access. But it required a commitment to teaching endeavours that was in tension with the institutional focus on research. Through a social realist analysis of the two discourses constructing relationships in the tutorial system, we conclude that these discourses have the power to both constrain and enable the extent to which the tutorial system can be a site of epistemological access.
- Full Text: false
- Date Issued: 2016
Revisiting cellulase production and redefining current strategies based on major challenges
- Kuhad, Ramesh Chander, Deswal, Deepa, Sharma, Sonia, Bhattacharya, Abhishek, Jain, Kavish Kumar, Kaur, Amandeep, Pletschke, Brett I, Singh, Ajay, Karp, Matti
- Authors: Kuhad, Ramesh Chander , Deswal, Deepa , Sharma, Sonia , Bhattacharya, Abhishek , Jain, Kavish Kumar , Kaur, Amandeep , Pletschke, Brett I , Singh, Ajay , Karp, Matti
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66142 , vital:28909 , https://doi.org/10.1016/j.rser.2015.10.132
- Description: publisher version , Lignocellulosic biomass has been considered as an important and sustainable source of renewable energy. Cellulose constitutes the major component of the lignocellulosic biomass and also offers maximum recalcitrance towards its fullest utilization. The enzymatic breakdown of cellulose is achieved through cellulases. Diverse forms of microbes including fungi, bacteria, actinomycetes and yeast are known to produce cellulases that have found extensive application in various industries. Due to the current global political unrest over oil prices and the threat of global warming following combustion of fossil fuels, the paradigm of research is now focused on biofuel production from plant biomass. Conventional approaches have not been economically feasible for meeting the demands of the industry. This review provides an update regarding the status of present microbial cellulase production technologies and research with special reference to solid state fermentation and different molecular techniques such as mutagenesis, metabolic engineering and heterologous gene expression of cellulases from different microbial domains with improved catalytic and stability properties. Metagenomic and genomic studies for mining of novel cellulase genes in addition to screening of culturable strains using conventional methods have been advanced. In addition the bottlenecks associated with cellulase production and how the future research needs to be directed to provide a comprehensive technology for the production of cellulases with novel traits for application at an industrial level without economic constraints are discussed.
- Full Text: false
- Date Issued: 2016
- Authors: Kuhad, Ramesh Chander , Deswal, Deepa , Sharma, Sonia , Bhattacharya, Abhishek , Jain, Kavish Kumar , Kaur, Amandeep , Pletschke, Brett I , Singh, Ajay , Karp, Matti
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/66142 , vital:28909 , https://doi.org/10.1016/j.rser.2015.10.132
- Description: publisher version , Lignocellulosic biomass has been considered as an important and sustainable source of renewable energy. Cellulose constitutes the major component of the lignocellulosic biomass and also offers maximum recalcitrance towards its fullest utilization. The enzymatic breakdown of cellulose is achieved through cellulases. Diverse forms of microbes including fungi, bacteria, actinomycetes and yeast are known to produce cellulases that have found extensive application in various industries. Due to the current global political unrest over oil prices and the threat of global warming following combustion of fossil fuels, the paradigm of research is now focused on biofuel production from plant biomass. Conventional approaches have not been economically feasible for meeting the demands of the industry. This review provides an update regarding the status of present microbial cellulase production technologies and research with special reference to solid state fermentation and different molecular techniques such as mutagenesis, metabolic engineering and heterologous gene expression of cellulases from different microbial domains with improved catalytic and stability properties. Metagenomic and genomic studies for mining of novel cellulase genes in addition to screening of culturable strains using conventional methods have been advanced. In addition the bottlenecks associated with cellulase production and how the future research needs to be directed to provide a comprehensive technology for the production of cellulases with novel traits for application at an industrial level without economic constraints are discussed.
- Full Text: false
- Date Issued: 2016
The (in)significance of the common law? Constitutional interpretation and the Mansingh judgments
- Authors: Krüger, Rósaan
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68900 , vital:29337 , https://hdl.handle.net/10520/EJC155168
- Description: Publisher version , The law reports abound with case law on the interpretation of the provisions in the Bill of Rights. Cases on the interpretation of constitutional provisions that fall outside of the Bill of Rights are, by contrast, few and far between. (A few prominent examples are S v Mhlungu 1995 (3) SA 867 (CC); President of the Republic of South Africa v South African Rugby Football Union 2000 (1) SA 1 (CC) ('SARFU'); Matatiele Municipality v President of the Republic of South Africa 2006 (5) SA 47 (CC); Doctors for Life International v Speaker of the National Assembly 2006 (6) SA 416 (CC); Merafong Demarcation Forum v President of the Republic of South Africa 2008 (5) SA171 (CC); Chonco v President of the Republic of South Africa 2010 (6) BCLR 511 (CC); Albutt v Centre for the Study of Violence and Reconciliation 2010 (3) SA 293 (CC).) Mansingh's April 2011 application to the North Gauteng High Court was one of these unusual cases.
- Full Text: false
- Date Issued: 2014
- Authors: Krüger, Rósaan
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68900 , vital:29337 , https://hdl.handle.net/10520/EJC155168
- Description: Publisher version , The law reports abound with case law on the interpretation of the provisions in the Bill of Rights. Cases on the interpretation of constitutional provisions that fall outside of the Bill of Rights are, by contrast, few and far between. (A few prominent examples are S v Mhlungu 1995 (3) SA 867 (CC); President of the Republic of South Africa v South African Rugby Football Union 2000 (1) SA 1 (CC) ('SARFU'); Matatiele Municipality v President of the Republic of South Africa 2006 (5) SA 47 (CC); Doctors for Life International v Speaker of the National Assembly 2006 (6) SA 416 (CC); Merafong Demarcation Forum v President of the Republic of South Africa 2008 (5) SA171 (CC); Chonco v President of the Republic of South Africa 2010 (6) BCLR 511 (CC); Albutt v Centre for the Study of Violence and Reconciliation 2010 (3) SA 293 (CC).) Mansingh's April 2011 application to the North Gauteng High Court was one of these unusual cases.
- Full Text: false
- Date Issued: 2014
Sex work from a feminist perspective: a visit to the Jordan case
- Authors: Krüger, Rósaan
- Date: 2004
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68877 , vital:29335 , https://doi.org/10.1080/19962126.2004.11864812
- Description: Publisher version , Introduction: Contributors to the prostitution/sex work debate, whether they condone, support or oppose criminalisation, legalisation or decriminalisation of prostitution, often rely on ‘facts’ to support their arguments. A common fact is that the majority of prostitutes/sex workers in the world and in South Africa are women. Thus, when I refer to prostitutes/sex workers, I refer to women working as prostitutes in the commercial sex industry. Furthermore, the fact that the majority of sex workers are women justifies considering prostitution from a feminist perspective – women’s voices on the subject should be heard. In this note I shall use the terms ‘prostitution’ and ‘sex work’ to refer to the exchange of sexual services for money. The former, more conventional term has a negative connotation, while the term ‘sex work’ denotes a movement away from casting a moral judgment towards recognition that sex work is just another job. References will be made to the associated activities of brothel-keeping and pimping, but the focus of this note is mainly on the provision of sexual services by the prostitute/ sex worker herself. Jordan v S is a Constitutional Court judgment in which the constitutional validity of the criminalisation of prostitution and its related activities were challenged. In order to analyse this judgment from a feminist perspective, I shall first briefly set out the current legal position on prostitution. Thereafter, I shall give an overview of Western feminist perspectives on prostitution and then link this perspective with African feminism. The last part of the note will be an analysis of the Jordan judgment in light of the feminist perspectives identified before.
- Full Text: false
- Date Issued: 2004
- Authors: Krüger, Rósaan
- Date: 2004
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68877 , vital:29335 , https://doi.org/10.1080/19962126.2004.11864812
- Description: Publisher version , Introduction: Contributors to the prostitution/sex work debate, whether they condone, support or oppose criminalisation, legalisation or decriminalisation of prostitution, often rely on ‘facts’ to support their arguments. A common fact is that the majority of prostitutes/sex workers in the world and in South Africa are women. Thus, when I refer to prostitutes/sex workers, I refer to women working as prostitutes in the commercial sex industry. Furthermore, the fact that the majority of sex workers are women justifies considering prostitution from a feminist perspective – women’s voices on the subject should be heard. In this note I shall use the terms ‘prostitution’ and ‘sex work’ to refer to the exchange of sexual services for money. The former, more conventional term has a negative connotation, while the term ‘sex work’ denotes a movement away from casting a moral judgment towards recognition that sex work is just another job. References will be made to the associated activities of brothel-keeping and pimping, but the focus of this note is mainly on the provision of sexual services by the prostitute/ sex worker herself. Jordan v S is a Constitutional Court judgment in which the constitutional validity of the criminalisation of prostitution and its related activities were challenged. In order to analyse this judgment from a feminist perspective, I shall first briefly set out the current legal position on prostitution. Thereafter, I shall give an overview of Western feminist perspectives on prostitution and then link this perspective with African feminism. The last part of the note will be an analysis of the Jordan judgment in light of the feminist perspectives identified before.
- Full Text: false
- Date Issued: 2004
Of fences and peace between neighbours
- Authors: Krüger, Rósaan
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68909 , vital:29338 , https://hdl.handle.net/10520/EJC85309
- Description: Publisher version , The speaker in the poem "Mending Wall" by American poet Robert Frost questions the wisdom of the saying that "Good Fences Make Good Neighbo[u]rs" (1914 North of Boston lines 27 and 45). The walls or fences referred to in the poem represent more than just physical barriers separating adjacent premises; the speaker sees them as representing obstacles to communication and friendship between individuals. Seen from the perspective of the speaker, a fence or wall is a "bad" thing. But the speaker is but one of the parties to the neighbourly relationship. For the speaker's neighbour, a wall or a fence is "a protector of privacy" (Watson "Frost's Wall : The View from the Other Side" 1971 44 The New England Quarterly 653 655). Thus there are two views on walls or fences: they can be seen negatively as obstructing good relations, or positively as dividers that secure good relations between neighbours by separating them and protecting their privacy rights.
- Full Text: false
- Date Issued: 2009
- Authors: Krüger, Rósaan
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68909 , vital:29338 , https://hdl.handle.net/10520/EJC85309
- Description: Publisher version , The speaker in the poem "Mending Wall" by American poet Robert Frost questions the wisdom of the saying that "Good Fences Make Good Neighbo[u]rs" (1914 North of Boston lines 27 and 45). The walls or fences referred to in the poem represent more than just physical barriers separating adjacent premises; the speaker sees them as representing obstacles to communication and friendship between individuals. Seen from the perspective of the speaker, a fence or wall is a "bad" thing. But the speaker is but one of the parties to the neighbourly relationship. For the speaker's neighbour, a wall or a fence is "a protector of privacy" (Watson "Frost's Wall : The View from the Other Side" 1971 44 The New England Quarterly 653 655). Thus there are two views on walls or fences: they can be seen negatively as obstructing good relations, or positively as dividers that secure good relations between neighbours by separating them and protecting their privacy rights.
- Full Text: false
- Date Issued: 2009
Small steps to equal dignity: the work of the South African equality courts
- Authors: Krüger, Rósaan
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68920 , vital:29339 , http://www.equalrightstrust.org/ertdocumentbank/ERR7_kruger.pdf
- Description: Publisher version , Introduction: “The South African Constitution is primarily and emphatically an egalitarian constitution. The supreme laws of comparable constitutional states may underscore other principles and rights. But in the light of our own particular history, and our vision for the future, a constitution was written with equality at its centre. Equality is our Constitution’s focus and organising principle.” Given the foundational role of equality in the South African constitutional framework, the drafters of the South African Constitution (the Constitution) directed the South African Parliament (Parliament) to enact legislation to “prevent or prohibit unfair discrimination” between individuals within three years of the enactment of the Constitution.3 Under great pressure, Parliament finalised and passed the Promotion of Equality and Prevention of Unfair Discrimination Act (the Equality Act) within two days of the constitutional deadline.4 The Equality Act, as the title indicates, addresses the promotion of equality on the one hand, and provides for reactive measures where the equality right is breached, on the other. The reactive provisions include the prohibition of unfair discrimination and related infringements of the equality right. The Equality Act expressly provides for the enforcement of its provisions in specifically created equality courts. The majority of the reactive provisions of the Equality Act have been operational since 16 June 2003. More than a decade after the enactment of the legislation, the promotional aspects of the Equality Act are yet to come into operation. This article focuses on the reactive provisions of the Equality Act by providing a snapshot of the work of selected South African equality courts for the period from June 2003 to December 2007 insofar as complaints of racism are concerned. In order to contextualise the application of the Equality Act, the article provides a brief overview of the reactive provisions of the Equality Act and the mechanisms for its enforcement.
- Full Text: false
- Date Issued: 2011
- Authors: Krüger, Rósaan
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68920 , vital:29339 , http://www.equalrightstrust.org/ertdocumentbank/ERR7_kruger.pdf
- Description: Publisher version , Introduction: “The South African Constitution is primarily and emphatically an egalitarian constitution. The supreme laws of comparable constitutional states may underscore other principles and rights. But in the light of our own particular history, and our vision for the future, a constitution was written with equality at its centre. Equality is our Constitution’s focus and organising principle.” Given the foundational role of equality in the South African constitutional framework, the drafters of the South African Constitution (the Constitution) directed the South African Parliament (Parliament) to enact legislation to “prevent or prohibit unfair discrimination” between individuals within three years of the enactment of the Constitution.3 Under great pressure, Parliament finalised and passed the Promotion of Equality and Prevention of Unfair Discrimination Act (the Equality Act) within two days of the constitutional deadline.4 The Equality Act, as the title indicates, addresses the promotion of equality on the one hand, and provides for reactive measures where the equality right is breached, on the other. The reactive provisions include the prohibition of unfair discrimination and related infringements of the equality right. The Equality Act expressly provides for the enforcement of its provisions in specifically created equality courts. The majority of the reactive provisions of the Equality Act have been operational since 16 June 2003. More than a decade after the enactment of the legislation, the promotional aspects of the Equality Act are yet to come into operation. This article focuses on the reactive provisions of the Equality Act by providing a snapshot of the work of selected South African equality courts for the period from June 2003 to December 2007 insofar as complaints of racism are concerned. In order to contextualise the application of the Equality Act, the article provides a brief overview of the reactive provisions of the Equality Act and the mechanisms for its enforcement.
- Full Text: false
- Date Issued: 2011
Equality and unfair discrimination: refining the Harksen test
- Authors: Krüger, Rósaan
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68890 , vital:29336 , https://hdl.handle.net/10520/EJC53981
- Description: Publisher version , The 1997 formulation of the test in Harksen by Constitutional Court seemed to settle the constitutional standards in respect of equality and unfair discrimination. In this article this test is scrutinised closely with a view to clarify the different aspects of the right protected in s 9. Reliance is further placed on Canadian commentary which interrogates the dignity-centred analysis of the Canadian Supreme Court in relation to the Canadian Charter's prohibition of discrimination. The similar insistence on dignity as the interest protected by the right to equality opens up new possibilities in the South African context. Accordingly, specific 'wrongs' or 'indignities' of inequality are identified, which refines the Harksen test. The identification of the indignities, it is suggested, assists litigants and the court on a practical level when determining the fairness or otherwise of discrimination.
- Full Text: false
- Date Issued: 2011
- Authors: Krüger, Rósaan
- Date: 2011
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68890 , vital:29336 , https://hdl.handle.net/10520/EJC53981
- Description: Publisher version , The 1997 formulation of the test in Harksen by Constitutional Court seemed to settle the constitutional standards in respect of equality and unfair discrimination. In this article this test is scrutinised closely with a view to clarify the different aspects of the right protected in s 9. Reliance is further placed on Canadian commentary which interrogates the dignity-centred analysis of the Canadian Supreme Court in relation to the Canadian Charter's prohibition of discrimination. The similar insistence on dignity as the interest protected by the right to equality opens up new possibilities in the South African context. Accordingly, specific 'wrongs' or 'indignities' of inequality are identified, which refines the Harksen test. The identification of the indignities, it is suggested, assists litigants and the court on a practical level when determining the fairness or otherwise of discrimination.
- Full Text: false
- Date Issued: 2011
A case study of the opportunities and trade-offs associated with deproclamation of a protected area following a land claim in South Africa
- Krüger, Ruth, Cundill, Georgina, Thondhlana, Gladman
- Authors: Krüger, Ruth , Cundill, Georgina , Thondhlana, Gladman
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67791 , vital:29145 , https://doi.org/10.1080/13549839.2015.1065804
- Description: Publisher version , Reconciling conservation and social justice imperatives is a major challenge facing many postcolonial states worldwide. Where historically disenfranchised communities have laid legal claim to protected areas, the typical resolution has been collaborative management agreements between the state and claimant communities. The real outcomes of such strategies for people and ecosystems have been seriously questioned, although alternative approaches are seldom explored. Here, we reflect on one such alternative that was pursued in a case in South Africa, where the land was handed back to the community and a replacement protected area created. Our objective was to explore the opportunities and trade-offs associated with this approach for communities and conservation agencies alike, and to compare these to typical collaborative management outcomes. Methods included key informant interviews, focus group discussions and household surveys. We find that, surprisingly, this approach created more benefits for the conservation agency than for claimant communities. Indeed, the community experiences bore a striking resemblance to those experienced in collaborative management settings: intra-community conflict, confusion over leadership and serious questions about the boundaries of the “community”. Processes aimed at redressing past injustice in disputes over conservation land, regardless of the approach adopted, must bring with them a strong commitment to building institutional and leadership capacities within communities, and pay serious attention to the ways in which equity and social justice can be fostered after the settlement of a land claim. Settlement agreements are frequently treated as the final step towards social justice, but are in fact just the beginning.
- Full Text: false
- Date Issued: 2016
- Authors: Krüger, Ruth , Cundill, Georgina , Thondhlana, Gladman
- Date: 2016
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67791 , vital:29145 , https://doi.org/10.1080/13549839.2015.1065804
- Description: Publisher version , Reconciling conservation and social justice imperatives is a major challenge facing many postcolonial states worldwide. Where historically disenfranchised communities have laid legal claim to protected areas, the typical resolution has been collaborative management agreements between the state and claimant communities. The real outcomes of such strategies for people and ecosystems have been seriously questioned, although alternative approaches are seldom explored. Here, we reflect on one such alternative that was pursued in a case in South Africa, where the land was handed back to the community and a replacement protected area created. Our objective was to explore the opportunities and trade-offs associated with this approach for communities and conservation agencies alike, and to compare these to typical collaborative management outcomes. Methods included key informant interviews, focus group discussions and household surveys. We find that, surprisingly, this approach created more benefits for the conservation agency than for claimant communities. Indeed, the community experiences bore a striking resemblance to those experienced in collaborative management settings: intra-community conflict, confusion over leadership and serious questions about the boundaries of the “community”. Processes aimed at redressing past injustice in disputes over conservation land, regardless of the approach adopted, must bring with them a strong commitment to building institutional and leadership capacities within communities, and pay serious attention to the ways in which equity and social justice can be fostered after the settlement of a land claim. Settlement agreements are frequently treated as the final step towards social justice, but are in fact just the beginning.
- Full Text: false
- Date Issued: 2016
The ebb and flow of the separation of powers in South African constitutional law – the Glenister litigation campaign
- Authors: Krüger, Rósaan
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71103 , vital:29784 , https://doi.org/10.5771/0506-7286-2015-1-49
- Description: This article considers the application of the doctrine of separation of powers by the South African judiciary in a series of judgments flowing from applications and appeals concerning the disbanding of a specialised crime-fighting unit, the Directorate of Special Operations (‘DSO’, colloquially known as ‘the Scorpions’) and the establishment of another unit, the Directorate of Priority Crimes (‘DCPI’, colloquially known as ‘the Hawks’) through legislative enactment. It traces the judiciary’s stance on the separation of powers in the different stages of the litigation - before, during and after the conclusion of the legislative process. It does so against the background of South African precedent on the doctrine and in the light of a perceived power imbalance between the branches of government. Ultimately, it questions the appropriateness of the current understanding of the doctrine of separation of powers in the context of a dominant-party democracy.
- Full Text: false
- Date Issued: 2015
- Authors: Krüger, Rósaan
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71103 , vital:29784 , https://doi.org/10.5771/0506-7286-2015-1-49
- Description: This article considers the application of the doctrine of separation of powers by the South African judiciary in a series of judgments flowing from applications and appeals concerning the disbanding of a specialised crime-fighting unit, the Directorate of Special Operations (‘DSO’, colloquially known as ‘the Scorpions’) and the establishment of another unit, the Directorate of Priority Crimes (‘DCPI’, colloquially known as ‘the Hawks’) through legislative enactment. It traces the judiciary’s stance on the separation of powers in the different stages of the litigation - before, during and after the conclusion of the legislative process. It does so against the background of South African precedent on the doctrine and in the light of a perceived power imbalance between the branches of government. Ultimately, it questions the appropriateness of the current understanding of the doctrine of separation of powers in the context of a dominant-party democracy.
- Full Text: false
- Date Issued: 2015
The recognition of unenumerated rights in South Africa
- Krüger, Rósaan, Govindjee, Avinash
- Authors: Krüger, Rósaan , Govindjee, Avinash
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71093 , vital:29783 , https://hdl.handle.net/10520/EJC153177
- Description: In 1997 a South African man married a woman who, at the time of the conclusion of their marriage, was a national of a foreign country. The couple decided to set up home and start a family in South Africa. They were advised that the granting of a permanent residence permit to the wife would only be considered upon payment of a hefty application fee, and that she had to apply for the permit from outside South Africa. The couple was of the view that the high cost of the application coupled with their temporary separation at the time of the lodging of the application amounted to an unjustifiable limitation of their right to family life. One of the obstacles faced by the couple was the silence of the South Africa Constitution on the right to family life.
- Full Text: false
- Date Issued: 2012
- Authors: Krüger, Rósaan , Govindjee, Avinash
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71093 , vital:29783 , https://hdl.handle.net/10520/EJC153177
- Description: In 1997 a South African man married a woman who, at the time of the conclusion of their marriage, was a national of a foreign country. The couple decided to set up home and start a family in South Africa. They were advised that the granting of a permanent residence permit to the wife would only be considered upon payment of a hefty application fee, and that she had to apply for the permit from outside South Africa. The couple was of the view that the high cost of the application coupled with their temporary separation at the time of the lodging of the application amounted to an unjustifiable limitation of their right to family life. One of the obstacles faced by the couple was the silence of the South Africa Constitution on the right to family life.
- Full Text: false
- Date Issued: 2012
Conscientious objection to performing same-sex marriage in South Africa
- Authors: Kruuse, Helen
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/129186 , vital:36228 , https://doi.org/10.1093/lawfam/ebu001
- Description: This article considers whether public servants should be exempt from South Africa’s equality provisions and anti-discrimination legislation in solemnizing same-sex marriages. In order to deal with this question, the article analyses the treatment of freedom of conscience and conscientious objection by comparing the solemnization of same-sex marriage by public servants, with another public service: that of terminations of pregnancy. While each situation will inevitably turn on the particular circumstances of the case, I argue that there should be a content-neutral guiding principle (as well as consistency) in dealing with these situations. The issue in each situation is narrowed to whether a civil servant’s personal convictions can override the state’s secular obligations in providing a service, and whether there is room for a qualified right to conscientious objection. By analysing the matter in this way, it is clear that the unqualified statutory exemption clause in South Africa’s Civil Union Act is constitutionally objectionable.
- Full Text: false
- Date Issued: 2014
- Authors: Kruuse, Helen
- Date: 2014
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/129186 , vital:36228 , https://doi.org/10.1093/lawfam/ebu001
- Description: This article considers whether public servants should be exempt from South Africa’s equality provisions and anti-discrimination legislation in solemnizing same-sex marriages. In order to deal with this question, the article analyses the treatment of freedom of conscience and conscientious objection by comparing the solemnization of same-sex marriage by public servants, with another public service: that of terminations of pregnancy. While each situation will inevitably turn on the particular circumstances of the case, I argue that there should be a content-neutral guiding principle (as well as consistency) in dealing with these situations. The issue in each situation is narrowed to whether a civil servant’s personal convictions can override the state’s secular obligations in providing a service, and whether there is room for a qualified right to conscientious objection. By analysing the matter in this way, it is clear that the unqualified statutory exemption clause in South Africa’s Civil Union Act is constitutionally objectionable.
- Full Text: false
- Date Issued: 2014
Substantive second-level reasoning and experiential learning in legal ethics
- Authors: Kruuse, Helen
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68983 , vital:29345 , https://hdl.handle.net/10520/EJC127082
- Description: Publisher version , This article takes a critical look at law teaching in South Africa and seeks to consider how the application of experiential learning theory may assist law students in gaining a deeper understanding of the law in general, and the complexities of real life practice in particular. While clinical legal education is often seen as the locus of experiential learning in law, the author proposes that well-structured simulations in class can achieve similar goals. The article comprises a description of the nature of experiential learning and a further description of the application of the principles of experiential learning in a particular simulation exercise in a Legal Ethics course (using the US case of Wash St Phys Ins Exch v Fisons Corp 858 P2d 1054 (Wash 1993) as a basis). The author posits that the so-called experiential learning "cycle" or "process" enables a process of learning which draws out the students' beliefs and ideas about a topic so that it can be examined, tested and integrated with new, more refined ideas. This notion is then in keeping with the expectation that students who emerge from higher education institutions have developed meta-cognitive skills. Essentially then, it is hoped that, by using the methods proposed in this article, students can then manage their own development and learning throughout life.
- Full Text: false
- Date Issued: 2012
- Authors: Kruuse, Helen
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68983 , vital:29345 , https://hdl.handle.net/10520/EJC127082
- Description: Publisher version , This article takes a critical look at law teaching in South Africa and seeks to consider how the application of experiential learning theory may assist law students in gaining a deeper understanding of the law in general, and the complexities of real life practice in particular. While clinical legal education is often seen as the locus of experiential learning in law, the author proposes that well-structured simulations in class can achieve similar goals. The article comprises a description of the nature of experiential learning and a further description of the application of the principles of experiential learning in a particular simulation exercise in a Legal Ethics course (using the US case of Wash St Phys Ins Exch v Fisons Corp 858 P2d 1054 (Wash 1993) as a basis). The author posits that the so-called experiential learning "cycle" or "process" enables a process of learning which draws out the students' beliefs and ideas about a topic so that it can be examined, tested and integrated with new, more refined ideas. This notion is then in keeping with the expectation that students who emerge from higher education institutions have developed meta-cognitive skills. Essentially then, it is hoped that, by using the methods proposed in this article, students can then manage their own development and learning throughout life.
- Full Text: false
- Date Issued: 2012
Significance of 87Sr/86Sr ratios in the Merensky cyclic unit of the Bushveld Complex
- Kruger, Floris J, Marsh, Julian S
- Authors: Kruger, Floris J , Marsh, Julian S
- Date: 1982
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/133524 , vital:36986 , https://doi.org/10.1038/298053a0
- Description: In a number of mafic layered intrusions, layers with platinum group element (PGE) mineralization coincide with breaks in cumulus mineral composition and isotopic variation trends through the layered sequence1,2. For example, in the Bushveld Complex in South Africa, abrupt increases in initial 87Sr/86Sr ratios occur at the UG-2 and Merensky pegmatoid (or ‘reef’) horizons, both of which are exploited for PGEs. We report here the results of a detailed Sr-isotope study across the Merensky unit and its immediate foot- and hangingwall-rocks which, when considered together with new ideas on processes operating in magma chambers3–5, suggest that magma mixing and post-cumulus infiltration of liquids displaced from below were important during crystallization of the Merensky pegmatoid.
- Full Text: false
- Date Issued: 1982
- Authors: Kruger, Floris J , Marsh, Julian S
- Date: 1982
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/133524 , vital:36986 , https://doi.org/10.1038/298053a0
- Description: In a number of mafic layered intrusions, layers with platinum group element (PGE) mineralization coincide with breaks in cumulus mineral composition and isotopic variation trends through the layered sequence1,2. For example, in the Bushveld Complex in South Africa, abrupt increases in initial 87Sr/86Sr ratios occur at the UG-2 and Merensky pegmatoid (or ‘reef’) horizons, both of which are exploited for PGEs. We report here the results of a detailed Sr-isotope study across the Merensky unit and its immediate foot- and hangingwall-rocks which, when considered together with new ideas on processes operating in magma chambers3–5, suggest that magma mixing and post-cumulus infiltration of liquids displaced from below were important during crystallization of the Merensky pegmatoid.
- Full Text: false
- Date Issued: 1982
The mineralogy, petrology, and origin of the Merensky cyclic unit in the western Bushveld Complex
- Kruger, Floris J, Marsh, Julian S
- Authors: Kruger, Floris J , Marsh, Julian S
- Date: 1985
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/136024 , vital:37329 , https://doi.org/10.2113/gsecongeo.80.4.958
- Description: The Merensky cyclic unit of the Bushveld Complex represents the first products to crystallize after the influx and mixing of a large new batch of magma in the chamber. Excluding the Merensky pegmatoid, the Merensky cyclic unit grades upward from an orthopyroxenite at the base, through norite to anorthosite at the top of the sequence. It is followed by the very similar Bastard cyclic unit.
- Full Text: false
- Date Issued: 1985
- Authors: Kruger, Floris J , Marsh, Julian S
- Date: 1985
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/136024 , vital:37329 , https://doi.org/10.2113/gsecongeo.80.4.958
- Description: The Merensky cyclic unit of the Bushveld Complex represents the first products to crystallize after the influx and mixing of a large new batch of magma in the chamber. Excluding the Merensky pegmatoid, the Merensky cyclic unit grades upward from an orthopyroxenite at the base, through norite to anorthosite at the top of the sequence. It is followed by the very similar Bastard cyclic unit.
- Full Text: false
- Date Issued: 1985
The amaXhosa ukuthwala marriage custom in fact and fiction: a contemporary critique
- Kaschula, Russell H, Huisamen, Tim, Mostert, Andre, Nosilela, Bulelwa
- Authors: Kaschula, Russell H , Huisamen, Tim , Mostert, Andre , Nosilela, Bulelwa
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68344 , vital:29241 , https://doi.org/10.1080/02572117.2013.871454
- Description: publisher version , Ukuthwala is traditionally a marriage custom within the amaXhosa culture in South Africa which permits a ‘legal abduction’ of a bride-to-be. Similar customs of ‘bridal abduction’ exist, most notably in Kyrgyzstan, where it is known as ala kachuu. Research into these customs necessitates a more innovative approach to explore the impact of this social phenomenon. In this article the authors mobilise a fictional narrative to offer a backdrop for a comparative assessment of the impact of bridal ‘legal abduction’ and assess its contemporary status and role within a multicultural society which celebrates the rights of the individual while recognising the value and importance of maintaining cultural identity and traditions. Cultural dissonance has always been characteristic of modern and post-modern societies as they strive for a workable shared ethos. However, when customs such as ‘legal abduction’ (Mtuze, 1993:50) continue under the veil of cultural rights, the wider social sensibilities and perspectives can be at odds with the maintenance of such activities where these activities contradict the rights of the individual as enshrined for example in what can be seen as a liberal South African Constitution.
- Full Text: false
- Date Issued: 2013
- Authors: Kaschula, Russell H , Huisamen, Tim , Mostert, Andre , Nosilela, Bulelwa
- Date: 2013
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/68344 , vital:29241 , https://doi.org/10.1080/02572117.2013.871454
- Description: publisher version , Ukuthwala is traditionally a marriage custom within the amaXhosa culture in South Africa which permits a ‘legal abduction’ of a bride-to-be. Similar customs of ‘bridal abduction’ exist, most notably in Kyrgyzstan, where it is known as ala kachuu. Research into these customs necessitates a more innovative approach to explore the impact of this social phenomenon. In this article the authors mobilise a fictional narrative to offer a backdrop for a comparative assessment of the impact of bridal ‘legal abduction’ and assess its contemporary status and role within a multicultural society which celebrates the rights of the individual while recognising the value and importance of maintaining cultural identity and traditions. Cultural dissonance has always been characteristic of modern and post-modern societies as they strive for a workable shared ethos. However, when customs such as ‘legal abduction’ (Mtuze, 1993:50) continue under the veil of cultural rights, the wider social sensibilities and perspectives can be at odds with the maintenance of such activities where these activities contradict the rights of the individual as enshrined for example in what can be seen as a liberal South African Constitution.
- Full Text: false
- Date Issued: 2013
Teaching Mandarin in schools is another slap in the face for African languages
- Kaschula, Russell H, Nosilela, Bulelwa, Heugh, Kathleen, Hendricks, Monica, Maseko, Pamela
- Authors: Kaschula, Russell H , Nosilela, Bulelwa , Heugh, Kathleen , Hendricks, Monica , Maseko, Pamela
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67042 , vital:29023 , https://theconversation.com/teaching-mandarin-in-schools-is-another-slap-in-the-face-for-african-languages-48505
- Description: publisher version , It’s said that behind every powerful language is an army and money. Consider the case of English. In South Africa, as in its other colonies, the British arrived with the Bible in one hand and the breech-loader in the other. Behind them was the English language, military might and money. British missionaries wanted to convert Africa’s indigenous “heathens” to Christianity; to clone little English people on the continent through the medium of English. Next came the Afrikaners, descended from the Dutch. Their slaves created a “kitchen” language out of Dutch and called it Afrikaans. White Afrikaners appropriated it as their own and it became the language of apartheid. One of the tipping points of white rule was the 1976 Soweto uprising – a furious, powerful response to the news that Afrikaans would become a compulsory medium of instruction. Now there is a new potential coloniser on South Africa’s linguistic block. From 2016, Mandarin will be taught in the country’s schools as a Second Additional Language. This new government policy will see African languages bumped even further down the educational pecking order.
- Full Text: false
- Date Issued: 2015
- Authors: Kaschula, Russell H , Nosilela, Bulelwa , Heugh, Kathleen , Hendricks, Monica , Maseko, Pamela
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/67042 , vital:29023 , https://theconversation.com/teaching-mandarin-in-schools-is-another-slap-in-the-face-for-african-languages-48505
- Description: publisher version , It’s said that behind every powerful language is an army and money. Consider the case of English. In South Africa, as in its other colonies, the British arrived with the Bible in one hand and the breech-loader in the other. Behind them was the English language, military might and money. British missionaries wanted to convert Africa’s indigenous “heathens” to Christianity; to clone little English people on the continent through the medium of English. Next came the Afrikaners, descended from the Dutch. Their slaves created a “kitchen” language out of Dutch and called it Afrikaans. White Afrikaners appropriated it as their own and it became the language of apartheid. One of the tipping points of white rule was the 1976 Soweto uprising – a furious, powerful response to the news that Afrikaans would become a compulsory medium of instruction. Now there is a new potential coloniser on South Africa’s linguistic block. From 2016, Mandarin will be taught in the country’s schools as a Second Additional Language. This new government policy will see African languages bumped even further down the educational pecking order.
- Full Text: false
- Date Issued: 2015
Phototransferred thermoluminescence and thermally-assisted optically stimulated luminescence dosimetry using α-Al2O3:C,Mg annealed at 1200°C
- Kalita, Jitumani M, Chithambo, Makaiko L
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/105422 , vital:32511 , https://doi.org/10.1016/j.jlumin.2018.08.085
- Description: We report phototransferred thermoluminescence (PTTL) and thermally-assisted optically stimulated luminescence (TA-OSL) of α-Al2O3:C,Mg annealed at 1200 °C. PTTL is TL measured from an irradiated phosphor after its exposure to light. The other theme of this study, TA-OSL is the additional amount of luminescence optically stimulated from a sample over and above the amount that would be measured at room temperature. A sample irradiated to 10 Gy and preheated to 230 °C at 1 °C/s followed by illumination by 470 nm blue light produced four PTTL peaks at 53, 80, 102 and 173 °C. The PTTL peaks occur at the same positions as the corresponding conventional TL peaks. Their kinetic parameters are also similar. The intensity of the PTTL peaks increased with duration of illumination to a maximum within 200 s for doses between 1 Gy and 10 Gy. The dose response of each of the PTTL peaks at 80, 102 and 173 °C is linear within 1–15 Gy. The rate of fading is low and the peaks are reproducible. When the irradiated sample is optically stimulated at temperatures between 30 °C and 300 °C, after preheating to 500 °C, the intensity of its TA-OSL goes through a peak with temperature at 200 °C. Using the rising edge of the plot, activation energy of thermal assistance for a deep electron trap was estimated as (0.21 ± 0.02) eV. The TA-OSL dose response is sublinear from 10–250 Gy and saturates thereafter. The PTTL and TA-OSL analyses signify that the concentration of deep traps in α-Al2O3:C,Mg increased after annealing at 1200 °C. As a result, the sample produced better PTTL and TA-OSL response than when annealed at lower temperature.
- Full Text: false
- Date Issued: 2018
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/105422 , vital:32511 , https://doi.org/10.1016/j.jlumin.2018.08.085
- Description: We report phototransferred thermoluminescence (PTTL) and thermally-assisted optically stimulated luminescence (TA-OSL) of α-Al2O3:C,Mg annealed at 1200 °C. PTTL is TL measured from an irradiated phosphor after its exposure to light. The other theme of this study, TA-OSL is the additional amount of luminescence optically stimulated from a sample over and above the amount that would be measured at room temperature. A sample irradiated to 10 Gy and preheated to 230 °C at 1 °C/s followed by illumination by 470 nm blue light produced four PTTL peaks at 53, 80, 102 and 173 °C. The PTTL peaks occur at the same positions as the corresponding conventional TL peaks. Their kinetic parameters are also similar. The intensity of the PTTL peaks increased with duration of illumination to a maximum within 200 s for doses between 1 Gy and 10 Gy. The dose response of each of the PTTL peaks at 80, 102 and 173 °C is linear within 1–15 Gy. The rate of fading is low and the peaks are reproducible. When the irradiated sample is optically stimulated at temperatures between 30 °C and 300 °C, after preheating to 500 °C, the intensity of its TA-OSL goes through a peak with temperature at 200 °C. Using the rising edge of the plot, activation energy of thermal assistance for a deep electron trap was estimated as (0.21 ± 0.02) eV. The TA-OSL dose response is sublinear from 10–250 Gy and saturates thereafter. The PTTL and TA-OSL analyses signify that the concentration of deep traps in α-Al2O3:C,Mg increased after annealing at 1200 °C. As a result, the sample produced better PTTL and TA-OSL response than when annealed at lower temperature.
- Full Text: false
- Date Issued: 2018
The effect of annealing and beta irradiation on thermoluminescence spectra of α-Al2O3: C, Mg
- Kalita, Jitumani M, Chithambo, Makaiko L
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/112875 , vital:33669 , https://doi.org/10.1016/j.jlumin.2017.12.036
- Description: The effect of annealing on thermoluminescence spectra of beta irradiated α-Al2O3:C,Mg has been studied. Measurements were made on an un-annealed sample and samples annealed at 600, 700 and 900 °C. A glow curve measured at 1 °C/s from samples irradiated to 1 Gy shows a high intensity peak at 163 °C and six secondary peaks of weaker intensity at 43, 73, 195, 280, 329 and 370 °C. When the samples are annealed at 700 or 900 °C, an additional secondary peak appears at 100 °C. The thermoluminescence spectrum of an un-annealed sample measured at 1 °C/s between 300 and 700 nm shows the main emission band at ~ 410 nm and subsidiary emission bands at ~ 325 and 485 nm. The emission from samples annealed at 700 and 900 °C show similar bands except for a decrease in intensity of the emission at 485 nm. The emission bands at 325, 410 and 485 nm are attributed to F+, F and F22+(2Mg) -centres respectively. The decrease of the emission band at 485 nm is deduced to be due to the destruction of the F22+(2Mg) centre at 700 °C. The emission bands are unaffected by irradiation dose between 10 and 320 Gy. However, when the sample is annealed at or beyond 700 °C, any effects on the F+ and F centres emission can be easier distinguished particularly for doses greater than 10 Gy.
- Full Text: false
- Date Issued: 2018
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2018
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/112875 , vital:33669 , https://doi.org/10.1016/j.jlumin.2017.12.036
- Description: The effect of annealing on thermoluminescence spectra of beta irradiated α-Al2O3:C,Mg has been studied. Measurements were made on an un-annealed sample and samples annealed at 600, 700 and 900 °C. A glow curve measured at 1 °C/s from samples irradiated to 1 Gy shows a high intensity peak at 163 °C and six secondary peaks of weaker intensity at 43, 73, 195, 280, 329 and 370 °C. When the samples are annealed at 700 or 900 °C, an additional secondary peak appears at 100 °C. The thermoluminescence spectrum of an un-annealed sample measured at 1 °C/s between 300 and 700 nm shows the main emission band at ~ 410 nm and subsidiary emission bands at ~ 325 and 485 nm. The emission from samples annealed at 700 and 900 °C show similar bands except for a decrease in intensity of the emission at 485 nm. The emission bands at 325, 410 and 485 nm are attributed to F+, F and F22+(2Mg) -centres respectively. The decrease of the emission band at 485 nm is deduced to be due to the destruction of the F22+(2Mg) centre at 700 °C. The emission bands are unaffected by irradiation dose between 10 and 320 Gy. However, when the sample is annealed at or beyond 700 °C, any effects on the F+ and F centres emission can be easier distinguished particularly for doses greater than 10 Gy.
- Full Text: false
- Date Issued: 2018
Thermally and optically stimulated luminescence of natural red and blue corundum (Al2O3)
- Kalita, Jitumani M, Thomas, Sunil, Chithambo, Makaiko L
- Authors: Kalita, Jitumani M , Thomas, Sunil , Chithambo, Makaiko L
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/105177 , vital:32472 , https://doi.org/10.1016/j.jlumin.2018.09.058
- Description: We report the thermoluminescence (TL) and optically stimulated luminescence (OSL) of natural corundum (Al2O3) of two varieties; one red and the other blue. X-ray fluorescence spectroscopy of the samples show that the concentration of Al2O3 in the red corundum is 43.05% and 46.87% in the blue corundum. TL measurements carried out on un-annealed samples and samples annealed at 700 °C, 900 °C and 1200 °C show that the TL sensitivity increases with annealing. The sensitivity of the red corundum reaches a maximum after annealing at 900 °C whereas that of the blue corundum increases with annealing up to the maximum annealing temperature of 1200 °C used in this study. Both samples have a complex glow curve between 30 °C and 500 °C. The composite nature of the glow curves is deduced to be due to a continuum in the trap distribution in the crystal. The activation energy of the traps vary between 0.70 eV and 1.15 eV. The dose response of the red corundum under TL is linear within 100‒1000 Gy whereas that of the blue corundum is superlinear for the same dose range. The TL of both samples is reproducible but the signal fades with time between irradiation and measurement. Both samples produce OSL under 470 nm blue light stimulation. The dose response of the OSL is superlinear within 100‒1000 Gy. It is found that the samples also produce thermally-assisted OSL (TA-OSL) at elevated temperature. The TA-OSL intensity of the red corundum increases with dose up to 400 Gy and saturates thereafter. On the other hand, the intensity of the blue corundum increases consistently with dose from 100 Gy to 1000 Gy.
- Full Text: false
- Date Issued: 2019
- Authors: Kalita, Jitumani M , Thomas, Sunil , Chithambo, Makaiko L
- Date: 2019
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/105177 , vital:32472 , https://doi.org/10.1016/j.jlumin.2018.09.058
- Description: We report the thermoluminescence (TL) and optically stimulated luminescence (OSL) of natural corundum (Al2O3) of two varieties; one red and the other blue. X-ray fluorescence spectroscopy of the samples show that the concentration of Al2O3 in the red corundum is 43.05% and 46.87% in the blue corundum. TL measurements carried out on un-annealed samples and samples annealed at 700 °C, 900 °C and 1200 °C show that the TL sensitivity increases with annealing. The sensitivity of the red corundum reaches a maximum after annealing at 900 °C whereas that of the blue corundum increases with annealing up to the maximum annealing temperature of 1200 °C used in this study. Both samples have a complex glow curve between 30 °C and 500 °C. The composite nature of the glow curves is deduced to be due to a continuum in the trap distribution in the crystal. The activation energy of the traps vary between 0.70 eV and 1.15 eV. The dose response of the red corundum under TL is linear within 100‒1000 Gy whereas that of the blue corundum is superlinear for the same dose range. The TL of both samples is reproducible but the signal fades with time between irradiation and measurement. Both samples produce OSL under 470 nm blue light stimulation. The dose response of the OSL is superlinear within 100‒1000 Gy. It is found that the samples also produce thermally-assisted OSL (TA-OSL) at elevated temperature. The TA-OSL intensity of the red corundum increases with dose up to 400 Gy and saturates thereafter. On the other hand, the intensity of the blue corundum increases consistently with dose from 100 Gy to 1000 Gy.
- Full Text: false
- Date Issued: 2019
Comprehensive kinetic analysis of thermoluminescence peaks of α-Al2O3: C, Mg
- Kalita, Jitumani M, Chithambo, Makaiko L
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/116142 , vital:34323 , https://doi.org/10.1016/j.jlumin.2017.01.003
- Description: A comprehensive kinetic analysis of the glow peaks in α-Al2O3:C,Mg is reported. A thermoluminescence glow curve measured at 1 °C/s after beta irradiation to 1 Gy shows a high intensity peak hereafter referred to as the main peak at 161 °C and six lower intensity secondary peaks at 42, 72, 193, 279, 330, 370 °C respectively. For ease of reference, the secondary peaks are labelled as I, II, IV, V, VI and VII respectively and the main peak denoted peak III. Kinetic analysis of the glow peaks has been carried out using the initial rise, whole glow peak, peak shape, variable heating rate and glow curve deconvolution methods as well as by way of phosphorescence. Using Tm-Tstop, Tm-dose and phosphorescence analyses, the order of kinetics of the peaks has been evaluated as first order. Analysis by the peak shape, whole glow peak and deconvolution methods produce the same conclusion. The activation energy of peaks I through VII are calculated as ~0.83, 0.96, 1.37, 1.20, 1.15, 1.61 and 1.94 eV respectively. The frequency factors for all the peaks are of the order of 109 to 1014 s−1. The question of thermal quenching affecting the peaks was considered. The peaks III, IV and V, the only ones that could be conveniently studied in this regard, were found to be affected by thermal quenching. The activation energy for thermal quenching was calculated for peak III as 0.96±0.03 eV, for peak VI as 0.95±0.07 eV and for peak V as 1.26±0.08 eV. The thermal quenching phenomenon has been discussed with reference to F+ and F centres. An energy band model has been developed to discuss the luminescence mechanisms in α-Al2O3:C,Mg in light of finding in this work.
- Full Text: false
- Date Issued: 2017
- Authors: Kalita, Jitumani M , Chithambo, Makaiko L
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/116142 , vital:34323 , https://doi.org/10.1016/j.jlumin.2017.01.003
- Description: A comprehensive kinetic analysis of the glow peaks in α-Al2O3:C,Mg is reported. A thermoluminescence glow curve measured at 1 °C/s after beta irradiation to 1 Gy shows a high intensity peak hereafter referred to as the main peak at 161 °C and six lower intensity secondary peaks at 42, 72, 193, 279, 330, 370 °C respectively. For ease of reference, the secondary peaks are labelled as I, II, IV, V, VI and VII respectively and the main peak denoted peak III. Kinetic analysis of the glow peaks has been carried out using the initial rise, whole glow peak, peak shape, variable heating rate and glow curve deconvolution methods as well as by way of phosphorescence. Using Tm-Tstop, Tm-dose and phosphorescence analyses, the order of kinetics of the peaks has been evaluated as first order. Analysis by the peak shape, whole glow peak and deconvolution methods produce the same conclusion. The activation energy of peaks I through VII are calculated as ~0.83, 0.96, 1.37, 1.20, 1.15, 1.61 and 1.94 eV respectively. The frequency factors for all the peaks are of the order of 109 to 1014 s−1. The question of thermal quenching affecting the peaks was considered. The peaks III, IV and V, the only ones that could be conveniently studied in this regard, were found to be affected by thermal quenching. The activation energy for thermal quenching was calculated for peak III as 0.96±0.03 eV, for peak VI as 0.95±0.07 eV and for peak V as 1.26±0.08 eV. The thermal quenching phenomenon has been discussed with reference to F+ and F centres. An energy band model has been developed to discuss the luminescence mechanisms in α-Al2O3:C,Mg in light of finding in this work.
- Full Text: false
- Date Issued: 2017