Surface patterning using scanning electrochemical microscopy to locally trigger a “click” chemistry reaction
- Quinton, Damien, Maringa, Audacity, Griveau, Sophie, Nyokong, Tebello, Bedioui, Fethi
- Authors: Quinton, Damien , Maringa, Audacity , Griveau, Sophie , Nyokong, Tebello , Bedioui, Fethi
- Language: English
- Type: Article
- Identifier: vital:7331 , http://hdl.handle.net/10962/d1020592
- Description: We report on the surface micropatterning of conductive surfaces via the electrochemical triggering of a click reaction, the copper(I) catalyzed azide–alkyne cycloaddition reaction (CuAAC) by SECM via a two-step approach: (i) functionalization on the entire surface with azido-aryl groups by using the diazonium approach followed by (ii) the covalent linkage of alkyne-bearing ferrocene by CuAAC within a local area by SECM. More precisely, the click reaction was triggered by Cu(I) catalyst generation for 30 min at the SECM tip positioned ≈ 10 μm above the azido-aryl modified surface. The dimension of the spot obtained under these conditions was ≈ 75 μm. The electrochemical imaging by SECM of the ultra thin area locally clicked with ferrocene moieties was made thanks to the electrocatalytic properties of the ferrocene modified surface towards ferrocyanide electrooxidation. This local clicking procedure opens the gate to further controlled functionalization of restricted small substrates. , Original publication is available at http://dx.doi.org/10.1016/j.elecom.2013.03.021
- Full Text: false
- Authors: Quinton, Damien , Maringa, Audacity , Griveau, Sophie , Nyokong, Tebello , Bedioui, Fethi
- Language: English
- Type: Article
- Identifier: vital:7331 , http://hdl.handle.net/10962/d1020592
- Description: We report on the surface micropatterning of conductive surfaces via the electrochemical triggering of a click reaction, the copper(I) catalyzed azide–alkyne cycloaddition reaction (CuAAC) by SECM via a two-step approach: (i) functionalization on the entire surface with azido-aryl groups by using the diazonium approach followed by (ii) the covalent linkage of alkyne-bearing ferrocene by CuAAC within a local area by SECM. More precisely, the click reaction was triggered by Cu(I) catalyst generation for 30 min at the SECM tip positioned ≈ 10 μm above the azido-aryl modified surface. The dimension of the spot obtained under these conditions was ≈ 75 μm. The electrochemical imaging by SECM of the ultra thin area locally clicked with ferrocene moieties was made thanks to the electrocatalytic properties of the ferrocene modified surface towards ferrocyanide electrooxidation. This local clicking procedure opens the gate to further controlled functionalization of restricted small substrates. , Original publication is available at http://dx.doi.org/10.1016/j.elecom.2013.03.021
- Full Text: false
The development of catalytic oxovanadium(IV)-containing microspheres for the oxidation of various organosulfur compounds
- Ogunlaja, Adeniyi S, Khene, M Samson, Antunes, Edith M, Nyokong, Tebello, Torto, Nelson, Tshentu, Zenixole R
- Authors: Ogunlaja, Adeniyi S , Khene, M Samson , Antunes, Edith M , Nyokong, Tebello , Torto, Nelson , Tshentu, Zenixole R
- Language: English
- Type: Article
- Identifier: vital:7324 , http://hdl.handle.net/10962/d1020574
- Description: The development of poly[allylSB-co-EGDMA] beads containing a tetradentate ligand was achieved via suspension polymerization. The catalyst poly[allylSB-co-EGDMA]-VO was synthesized by reacting VIVOSO4 with poly[allylSB-co-EGDMA]. XPS and EPR were used to confirm the presence of vanadium (V4+) on the beads. The synthesized catalyst (poly[allylSB-co-EGDMA]-VO) was found to have a BET surface area of 22 m2 g−1 and porosity of 135 Å, with the atomic force microscopy (AFM) showing more insight on the porous nature of the beads. Oxidation of thiophene (TH), benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) was carried out using tert-butyl hydroperoxide (t-BuOOH) as oxidant. An overall conversion of 60%, 82%, 98% and 87% was achieved for thiophene (TH), benzothiophene (BT), dibenzothiophene (DBT) and 4,6 dimethyldibenzothiophene (4,6-DMDBT) respectively at higher (t-BuOOH) to substrate ratio and at a temperature of 40 °C. The efficient oxidation of the various organosulfur compounds presents potential for the possible application of this catalyst in oxidative desulfurization (ODS) of crude oil. , Original publication is available at http://dx.doi.org/10.1016/j.apcata.2013.05.004
- Full Text: false
- Authors: Ogunlaja, Adeniyi S , Khene, M Samson , Antunes, Edith M , Nyokong, Tebello , Torto, Nelson , Tshentu, Zenixole R
- Language: English
- Type: Article
- Identifier: vital:7324 , http://hdl.handle.net/10962/d1020574
- Description: The development of poly[allylSB-co-EGDMA] beads containing a tetradentate ligand was achieved via suspension polymerization. The catalyst poly[allylSB-co-EGDMA]-VO was synthesized by reacting VIVOSO4 with poly[allylSB-co-EGDMA]. XPS and EPR were used to confirm the presence of vanadium (V4+) on the beads. The synthesized catalyst (poly[allylSB-co-EGDMA]-VO) was found to have a BET surface area of 22 m2 g−1 and porosity of 135 Å, with the atomic force microscopy (AFM) showing more insight on the porous nature of the beads. Oxidation of thiophene (TH), benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) was carried out using tert-butyl hydroperoxide (t-BuOOH) as oxidant. An overall conversion of 60%, 82%, 98% and 87% was achieved for thiophene (TH), benzothiophene (BT), dibenzothiophene (DBT) and 4,6 dimethyldibenzothiophene (4,6-DMDBT) respectively at higher (t-BuOOH) to substrate ratio and at a temperature of 40 °C. The efficient oxidation of the various organosulfur compounds presents potential for the possible application of this catalyst in oxidative desulfurization (ODS) of crude oil. , Original publication is available at http://dx.doi.org/10.1016/j.apcata.2013.05.004
- Full Text: false
The human resource department as a strategic business partner in organisations
- Authors: Sakonda, Archford
- Subjects: Human capital -- Management , Strategic planning , Employment agencies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9431 , http://hdl.handle.net/10948/d1020178
- Description: The human resource department in many organisations is at a crossroad of relevance, constantly being faced with the challenge to prove that it can add value towards the objectives of the business. The Human Resource (HR) department is also faced with a reality that, if the department does not add value to the organisation, it will be farmed out to independent contractors, who can deliver the HR functions at a more efficient and cost effective way. However, organisations have a great opportunity to achieve excellence and competitive advantage through the utilisation of the organisation‟s human resources. Many scholars and authors argued that organisations can achieve the most out of its human resources if the HR department is a Strategic Business Partner (SBP) in these organisations. A thorough literature review has led to the discovery that, despite the appraisal of the Strategic Business Partners (SBP) approach to the management of human resources, little progress has been made with the reinvention of the HR departments from support function towards being a SBP (Lawler & Morhman, 2003; Keith, 2007). The slow progress in the transformation of the HR department was attributed to a wide range of factors including the lack of competencies to take up Strategic Business Partnership roles, lack of management support, and incongruent organisational cultures (Keith, 2007; Sanders & Frenkel, 2009; Ulrich & Brockbank, 2005). Semi-structured interviews were conducted with HR professionals, Managing Directors and other Directors, who sit on a strategic table, to identify the challenges and opportunities the HR department faced as a SBP in organisations. A self-administered questionnaire, based on an existing questionnaire (Ulrich & Cornell (1997) HR role assessment survey) was used to gather the perception of employees regarding the roles the HR departments play in organisations. In this study organisational culture was identified as having a huge impact towards the implementation of HR departments as SBPs. The study also identified the competencies needed for the effective execution of SBP roles, the challenges HR departments may face in the process as well as the important roles the HR department should be devoting most of its time and resources to.
- Full Text:
- Authors: Sakonda, Archford
- Subjects: Human capital -- Management , Strategic planning , Employment agencies
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9431 , http://hdl.handle.net/10948/d1020178
- Description: The human resource department in many organisations is at a crossroad of relevance, constantly being faced with the challenge to prove that it can add value towards the objectives of the business. The Human Resource (HR) department is also faced with a reality that, if the department does not add value to the organisation, it will be farmed out to independent contractors, who can deliver the HR functions at a more efficient and cost effective way. However, organisations have a great opportunity to achieve excellence and competitive advantage through the utilisation of the organisation‟s human resources. Many scholars and authors argued that organisations can achieve the most out of its human resources if the HR department is a Strategic Business Partner (SBP) in these organisations. A thorough literature review has led to the discovery that, despite the appraisal of the Strategic Business Partners (SBP) approach to the management of human resources, little progress has been made with the reinvention of the HR departments from support function towards being a SBP (Lawler & Morhman, 2003; Keith, 2007). The slow progress in the transformation of the HR department was attributed to a wide range of factors including the lack of competencies to take up Strategic Business Partnership roles, lack of management support, and incongruent organisational cultures (Keith, 2007; Sanders & Frenkel, 2009; Ulrich & Brockbank, 2005). Semi-structured interviews were conducted with HR professionals, Managing Directors and other Directors, who sit on a strategic table, to identify the challenges and opportunities the HR department faced as a SBP in organisations. A self-administered questionnaire, based on an existing questionnaire (Ulrich & Cornell (1997) HR role assessment survey) was used to gather the perception of employees regarding the roles the HR departments play in organisations. In this study organisational culture was identified as having a huge impact towards the implementation of HR departments as SBPs. The study also identified the competencies needed for the effective execution of SBP roles, the challenges HR departments may face in the process as well as the important roles the HR department should be devoting most of its time and resources to.
- Full Text:
The perceptions of educators, in the Queenstown education district, of the labour dispute resolution system
- Authors: Rataza, Themba Theophilus
- Subjects: Labor disputes -- South Africa -- Queenstown , Labor laws and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9434 , http://hdl.handle.net/10948/d1020542
- Description: The objective of this study is to conduct a survey concerning the perceptions of educators in the Queenstown education district of the labour dispute resolution system. The education department is one of the biggest departments in the Eastern Cape’s Provincial Administration system. The likelihood of disputes is high when there are many employees. The focus of the study therefore is on how educators perceive the role of the department in terms of ensuring that labour disputes with the department are resolved efficiently and speedily. The advent of a democratic dispensation resulted in the ushering in of progressive labour legislation such as Labour Relations Act 55 of 1995. The objective of this Act is to facilitate economic development, social justice, labour peace and democratization of the workplace. In other words this Act gave birth to the manner in which labour disputes should be resolved. The study was carried out not only to explore the perceptions of educators but also with a view to making recommendations on the findings in order to help contribute towards labour peace and productivity in the workplace. The attitudes of one hundred and forty-one educators were surveyed via questionnaires and six educators who have had labour disputes with the department were interviewed. The key findings of the study revealed that both the educators who were surveyed and those interviewed lack confidence in the effectiveness of the labour dispute procedures in the district; they perceive the system as being inaccessible to them; time taken to resolve disputes is too lengthy; the system lacks necessary independence from the department of education or government and the department is seen as not adhering to its own policies and legislation. Hence there are many disputes and there is a great need for more awareness and for improved training in handling labour dispute resolution systems for district officials and educators. The study recommends more awareness and training sessions for both district officials responsible for labour relations and educators at large. It also calls for an increasingly proactive role by teacher unions in partnership with the department of education to avoid labour disputes. Although the findings cannot be generalized toother districts of the province, they do however highlight critical areas in labour dispute resolution where attention can be paid and focus made in order to ensure labour peace in the workplace for improved productivity and effective teaching and learning.
- Full Text:
- Authors: Rataza, Themba Theophilus
- Subjects: Labor disputes -- South Africa -- Queenstown , Labor laws and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , MA
- Identifier: vital:9434 , http://hdl.handle.net/10948/d1020542
- Description: The objective of this study is to conduct a survey concerning the perceptions of educators in the Queenstown education district of the labour dispute resolution system. The education department is one of the biggest departments in the Eastern Cape’s Provincial Administration system. The likelihood of disputes is high when there are many employees. The focus of the study therefore is on how educators perceive the role of the department in terms of ensuring that labour disputes with the department are resolved efficiently and speedily. The advent of a democratic dispensation resulted in the ushering in of progressive labour legislation such as Labour Relations Act 55 of 1995. The objective of this Act is to facilitate economic development, social justice, labour peace and democratization of the workplace. In other words this Act gave birth to the manner in which labour disputes should be resolved. The study was carried out not only to explore the perceptions of educators but also with a view to making recommendations on the findings in order to help contribute towards labour peace and productivity in the workplace. The attitudes of one hundred and forty-one educators were surveyed via questionnaires and six educators who have had labour disputes with the department were interviewed. The key findings of the study revealed that both the educators who were surveyed and those interviewed lack confidence in the effectiveness of the labour dispute procedures in the district; they perceive the system as being inaccessible to them; time taken to resolve disputes is too lengthy; the system lacks necessary independence from the department of education or government and the department is seen as not adhering to its own policies and legislation. Hence there are many disputes and there is a great need for more awareness and for improved training in handling labour dispute resolution systems for district officials and educators. The study recommends more awareness and training sessions for both district officials responsible for labour relations and educators at large. It also calls for an increasingly proactive role by teacher unions in partnership with the department of education to avoid labour disputes. Although the findings cannot be generalized toother districts of the province, they do however highlight critical areas in labour dispute resolution where attention can be paid and focus made in order to ensure labour peace in the workplace for improved productivity and effective teaching and learning.
- Full Text:
The use of phthalocyanines in cancer therapy
- Nyokong, Tebello, Gledhill, Igle
- Authors: Nyokong, Tebello , Gledhill, Igle
- Language: English
- Type: Article
- Identifier: vital:7323 , http://hdl.handle.net/10962/d1020572
- Description: Phthalocyanines are synthetic analogues of porphyrins employed as photosensitizers in cancer therapy. We present the history of photodynamic therapy and developments in the use of phthalocyanines as photosensitizers. New efforts in the development of more cancer-specific phthalocyanines are presented. The combination of phthalocyanines with nanoparticles for "combination therapy" of cancer is also discussed. The nanoparticles employed are quantum dots, gold, and magnetic nanoparticles. , Original publication is available at http://dx.doi.org/10.10631.4794220
- Full Text: false
- Authors: Nyokong, Tebello , Gledhill, Igle
- Language: English
- Type: Article
- Identifier: vital:7323 , http://hdl.handle.net/10962/d1020572
- Description: Phthalocyanines are synthetic analogues of porphyrins employed as photosensitizers in cancer therapy. We present the history of photodynamic therapy and developments in the use of phthalocyanines as photosensitizers. New efforts in the development of more cancer-specific phthalocyanines are presented. The combination of phthalocyanines with nanoparticles for "combination therapy" of cancer is also discussed. The nanoparticles employed are quantum dots, gold, and magnetic nanoparticles. , Original publication is available at http://dx.doi.org/10.10631.4794220
- Full Text: false
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:
Ultrafast Photodynamics of the Indoline Dye D149 Adsorbed to Porous ZnO in Dye-Sensitized Solar Cells
- Rohwer, Egmont, Richter, Christoph, Heming, Nadine, Strauch, Kerstin, Litwinski, Christian, Nyokong, Tebello, Schlettwein, Derck, Schwoerer, Heinrich
- Authors: Rohwer, Egmont , Richter, Christoph , Heming, Nadine , Strauch, Kerstin , Litwinski, Christian , Nyokong, Tebello , Schlettwein, Derck , Schwoerer, Heinrich
- Language: English
- Type: Article
- Identifier: vital:7326 , http://hdl.handle.net/10962/d1020576
- Description: We investigate the ultrafast dynamics of the photoinduced electron transfer between surface-adsorbed indoline D149 dye and porous ZnO as used in the working electrodes of dye-sensitized solar cells. Transient absorption spectroscopy was conducted on the dye in solution, on solid state samples and for the latter in contact to a I−/I3− redox electrolyte typical for dye-sensitized solar cells to elucidate the effect of each component in the observed dynamics. D149 in a solution of 1:1 acetonitrile and tert-butyl alcohol shows excited-state lifetimes of 300±50 ps. This signature is severely quenched when D149 is adsorbed to ZnO, with the fastest component of the decay trace measured at 150±20 fs due to the charge-transfer mechanism. Absorption bands of the oxidized dye molecule were investigated to determine regeneration times which are in excess of 1 ns. The addition of the redox electrolyte to the system results in faster regeneration times, of the order of 1 ns. , Original publication is available at http://dx.doi.org/10.1002/cphc.201200715
- Full Text: false
- Authors: Rohwer, Egmont , Richter, Christoph , Heming, Nadine , Strauch, Kerstin , Litwinski, Christian , Nyokong, Tebello , Schlettwein, Derck , Schwoerer, Heinrich
- Language: English
- Type: Article
- Identifier: vital:7326 , http://hdl.handle.net/10962/d1020576
- Description: We investigate the ultrafast dynamics of the photoinduced electron transfer between surface-adsorbed indoline D149 dye and porous ZnO as used in the working electrodes of dye-sensitized solar cells. Transient absorption spectroscopy was conducted on the dye in solution, on solid state samples and for the latter in contact to a I−/I3− redox electrolyte typical for dye-sensitized solar cells to elucidate the effect of each component in the observed dynamics. D149 in a solution of 1:1 acetonitrile and tert-butyl alcohol shows excited-state lifetimes of 300±50 ps. This signature is severely quenched when D149 is adsorbed to ZnO, with the fastest component of the decay trace measured at 150±20 fs due to the charge-transfer mechanism. Absorption bands of the oxidized dye molecule were investigated to determine regeneration times which are in excess of 1 ns. The addition of the redox electrolyte to the system results in faster regeneration times, of the order of 1 ns. , Original publication is available at http://dx.doi.org/10.1002/cphc.201200715
- Full Text: false