Comparison of the structural configuration of cobalt nanoparticles on titania and titania nanotube supports
- Afolabi, A. S., Abdulkareem, A. S., Muzenda, Edison
- Authors: Afolabi, A. S. , Abdulkareem, A. S. , Muzenda, Edison
- Date: 2012
- Subjects: Cobaly catalysts , Titania , Titania nanotubes
- Type: Article
- Identifier: uj:4676 , ISSN 2306-4277 , http://hdl.handle.net/10210/10445
- Description: In this study, two cobalt based catalyst samples were prepared on titania and titania nanotubes supports using the deposition precipitation method. Their structural configurations were characterized and compared using BET, and TRP analyses. The BET analysis showed that the surface area of TiO2 is much higher than that of TNT which was due to their structural differences. Analyses of the results obtained revealed that the surface area of the 10 % Co/TNT catalyst sample is higher than that of the 10 % Co/TiO2. The TPR analysis showed that it is much easier to reduce 10 % Co/TiO2, than 10 % Co/TNT. This is attributed to be due to the fact that the cobalt particles were adsorbed on the surface of the TiO2, and formed covalent bonds with TNT. Therefore reduction temperature was higher with TNT than TiO2. The investigation of structural changes of these catalysts when they were coated with carbon, using chemical vapour deposition method was also conducted. The catalyst prepared on TNT support showed better properties in terms of average pore diameter, pore volume and surface area than the catalyst sample prepared on TiO2 support when the two samples were exposed to carbon environment for the same period of time.
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- Authors: Afolabi, A. S. , Abdulkareem, A. S. , Muzenda, Edison
- Date: 2012
- Subjects: Cobaly catalysts , Titania , Titania nanotubes
- Type: Article
- Identifier: uj:4676 , ISSN 2306-4277 , http://hdl.handle.net/10210/10445
- Description: In this study, two cobalt based catalyst samples were prepared on titania and titania nanotubes supports using the deposition precipitation method. Their structural configurations were characterized and compared using BET, and TRP analyses. The BET analysis showed that the surface area of TiO2 is much higher than that of TNT which was due to their structural differences. Analyses of the results obtained revealed that the surface area of the 10 % Co/TNT catalyst sample is higher than that of the 10 % Co/TiO2. The TPR analysis showed that it is much easier to reduce 10 % Co/TiO2, than 10 % Co/TNT. This is attributed to be due to the fact that the cobalt particles were adsorbed on the surface of the TiO2, and formed covalent bonds with TNT. Therefore reduction temperature was higher with TNT than TiO2. The investigation of structural changes of these catalysts when they were coated with carbon, using chemical vapour deposition method was also conducted. The catalyst prepared on TNT support showed better properties in terms of average pore diameter, pore volume and surface area than the catalyst sample prepared on TiO2 support when the two samples were exposed to carbon environment for the same period of time.
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Parametric effects on leaching behavior of nickel-copper matte in ammonia
- Muzenda, E., Ramatsa, I. M., Ntuli, F., Abdulkareem, A. S., Afolabi, A. S.
- Authors: Muzenda, E. , Ramatsa, I. M. , Ntuli, F. , Abdulkareem, A. S. , Afolabi, A. S.
- Date: 2013
- Subjects: Ammonia concentration , Copper , Leaching temperature , Leaching time , Nickel
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/17296 , uj:15867 , Citation: Muzenda, E. et al. 2013. Parametric effects on leaching behaviour of nickel-copper matte in ammonia. Particulate Science and Technology : An international Journal. 31(4): 319-325
- Description: Abstract: Please refer to full text for abstract
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- Authors: Muzenda, E. , Ramatsa, I. M. , Ntuli, F. , Abdulkareem, A. S. , Afolabi, A. S.
- Date: 2013
- Subjects: Ammonia concentration , Copper , Leaching temperature , Leaching time , Nickel
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/17296 , uj:15867 , Citation: Muzenda, E. et al. 2013. Parametric effects on leaching behaviour of nickel-copper matte in ammonia. Particulate Science and Technology : An international Journal. 31(4): 319-325
- Description: Abstract: Please refer to full text for abstract
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Modeling of the mechanical responses of nanocrystalline metals and alloys
- Sanusi, K. O., Afolabi, A. S., Muzenda, E., Akinlabi, Esther Titilayo
- Authors: Sanusi, K. O. , Afolabi, A. S. , Muzenda, E. , Akinlabi, Esther Titilayo
- Date: 2015-07-01
- Subjects: Nanocrystalline materials , Hall-Petch relations , Nanocrystalline alloys
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/390253 , uj:5122 , ISBN 9789881404701 , http://hdl.handle.net/10210/14083
- Description: This paper reports the proposed model of the flow behaviors of nanocrystalline metals and alloys deformed at different strains, strain rates and temperatures. It incorporated the effect of grain size, high internal stresses and lattice distortions existing near boundaries to the Hall-Petch relations. The developed model was compared to that of Khan-Huang-Liang and found to be more reliable in clarifying the inverse Hall-Petch relation. Using the new proposed constitutive model, the mechanical behaviour of materials at different grain sizes for ultrafine grained to nanostructure materials at different temperatures and strain rates can be obtained. The model is also useful in predicting the response of nanocrystalline metals and alloys during the forming process.
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- Authors: Sanusi, K. O. , Afolabi, A. S. , Muzenda, E. , Akinlabi, Esther Titilayo
- Date: 2015-07-01
- Subjects: Nanocrystalline materials , Hall-Petch relations , Nanocrystalline alloys
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/390253 , uj:5122 , ISBN 9789881404701 , http://hdl.handle.net/10210/14083
- Description: This paper reports the proposed model of the flow behaviors of nanocrystalline metals and alloys deformed at different strains, strain rates and temperatures. It incorporated the effect of grain size, high internal stresses and lattice distortions existing near boundaries to the Hall-Petch relations. The developed model was compared to that of Khan-Huang-Liang and found to be more reliable in clarifying the inverse Hall-Petch relation. Using the new proposed constitutive model, the mechanical behaviour of materials at different grain sizes for ultrafine grained to nanostructure materials at different temperatures and strain rates can be obtained. The model is also useful in predicting the response of nanocrystalline metals and alloys during the forming process.
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Weight loss and microstructural studies of stressed mild steel in apple juice
- Afolabi, A. S., Muhirwa, A. C., Abdulkareem, A. S, Muzenda, Edison
- Authors: Afolabi, A. S. , Muhirwa, A. C. , Abdulkareem, A. S , Muzenda, Edison
- Date: 2014
- Subjects: Apple juice , Weight loss
- Type: Article
- Identifier: uj:4814 , ISSN 1452-3981 , http://hdl.handle.net/10210/12255
- Description: This study investigated the effect of internal stress of mild steel on its corrosion behaviour in apple juice by weight loss and microstructural analyses....read full paper
- Full Text:
- Authors: Afolabi, A. S. , Muhirwa, A. C. , Abdulkareem, A. S , Muzenda, Edison
- Date: 2014
- Subjects: Apple juice , Weight loss
- Type: Article
- Identifier: uj:4814 , ISSN 1452-3981 , http://hdl.handle.net/10210/12255
- Description: This study investigated the effect of internal stress of mild steel on its corrosion behaviour in apple juice by weight loss and microstructural analyses....read full paper
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Predictive mathematical modeling and computer simulation of direct ethanol fuel cell
- Abdulkareem, A. S., Jimoh, A., Afolabi, A. S., Muzenda, E., Okeke, A. C.
- Authors: Abdulkareem, A. S. , Jimoh, A. , Afolabi, A. S. , Muzenda, E. , Okeke, A. C.
- Date: 2016
- Subjects: Fuel cell , Direct ethanol fuel cell , Predictive mathematical modeling
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/213692 , uj:21184 , Citation: Abdulkareem, A.S. et al. 2016. Predictive mathematical modeling and computer simulation of direct ethanol fuel cell.
- Description: Abstract: The challenges of finding a better substitute of energy as well as the short comings identify with direct ethanol fuel cell, this includes; high anode over potential and crossover necessitate the need to investigate the influence operating parameters on the performance of fuel through computer simulation. This study focus on the development of a predictive mathematical modeling for direct ethanol fuel cell for the purpose of investigating the influence pressure, temperature cathode and reactants concentration on the performance, efficiency and heat generated by the cell. Results obtained indicate that increase in operating temperature resulted led to decrement in output voltage and cell efficiency, while same condition of increasing the temperature positively favour the heat generated from the cell. Simulated results also show that cell performance is improved with increase in concentration of the fuel (ethanol) and oxidant (oxygen). It can be inferred from this study that the cell performance of DEFC can be theoretically predicted with the developed model.
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- Authors: Abdulkareem, A. S. , Jimoh, A. , Afolabi, A. S. , Muzenda, E. , Okeke, A. C.
- Date: 2016
- Subjects: Fuel cell , Direct ethanol fuel cell , Predictive mathematical modeling
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/213692 , uj:21184 , Citation: Abdulkareem, A.S. et al. 2016. Predictive mathematical modeling and computer simulation of direct ethanol fuel cell.
- Description: Abstract: The challenges of finding a better substitute of energy as well as the short comings identify with direct ethanol fuel cell, this includes; high anode over potential and crossover necessitate the need to investigate the influence operating parameters on the performance of fuel through computer simulation. This study focus on the development of a predictive mathematical modeling for direct ethanol fuel cell for the purpose of investigating the influence pressure, temperature cathode and reactants concentration on the performance, efficiency and heat generated by the cell. Results obtained indicate that increase in operating temperature resulted led to decrement in output voltage and cell efficiency, while same condition of increasing the temperature positively favour the heat generated from the cell. Simulated results also show that cell performance is improved with increase in concentration of the fuel (ethanol) and oxidant (oxygen). It can be inferred from this study that the cell performance of DEFC can be theoretically predicted with the developed model.
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