Metal injection moulding as a possible processing route for porous prostheses
- Authors: Bhero, Shepherd
- Date: 2014
- Subjects: Metal injection moulding , Porous prostheses , Full-density prostheses
- Type: Article
- Identifier: uj:4903 , ISSN 2349-1442 , http://hdl.handle.net/10210/13001
- Description: Metal injection moulding (MIM) can be used to make close to full density parts. The superiority of MIM over conventional casting and machining lies in lower cost and shorter processing time. Of paramount importance is the fact that powder processing circumvents the typical casting problems that include macro-segregation and discontinuities. Thus powder processing is a possible route for manufacturing full-density prostheses devoid of casting imperfections. However, the full density metallic part is much higher than that of bone tissue and would exert skewed weight on the skeletal configuration. This paper explores the feasibility of producing high strength porous prostheses in a bid to lower the overall implant density and to a lesser extent, stiffness, so as to match the bone properties as closely as possible. Powder characteristics and sintering parameters are critical in achieving the desired end.
- Full Text:
- Authors: Bhero, Shepherd
- Date: 2014
- Subjects: Metal injection moulding , Porous prostheses , Full-density prostheses
- Type: Article
- Identifier: uj:4903 , ISSN 2349-1442 , http://hdl.handle.net/10210/13001
- Description: Metal injection moulding (MIM) can be used to make close to full density parts. The superiority of MIM over conventional casting and machining lies in lower cost and shorter processing time. Of paramount importance is the fact that powder processing circumvents the typical casting problems that include macro-segregation and discontinuities. Thus powder processing is a possible route for manufacturing full-density prostheses devoid of casting imperfections. However, the full density metallic part is much higher than that of bone tissue and would exert skewed weight on the skeletal configuration. This paper explores the feasibility of producing high strength porous prostheses in a bid to lower the overall implant density and to a lesser extent, stiffness, so as to match the bone properties as closely as possible. Powder characteristics and sintering parameters are critical in achieving the desired end.
- Full Text:
Enrichment of biogas for use as vehicular fuel: a review of the upgrading techniques
- Masebinu, S. O., Aboyade, A., Muzenda, Edison
- Authors: Masebinu, S. O. , Aboyade, A. , Muzenda, Edison
- Date: 2014
- Subjects: Biogas , Biogas enrichment
- Type: Article
- Identifier: uj:4912 , ISSN 2349-1442 , http://hdl.handle.net/10210/13012
- Description: Biogas, a renewable energy, can be captured, upgraded and used to fuel a vehicle as an alternative to fossil fuel, thus, reducing greenhouse gas emission. Biogas is environmentally hazardous if emitted directly into the environment. Increasing demand for bio-methane to be used as vehicular fuel has called for efficient use of waste and technology that is optimal yet economical. Biogas in its raw state contains impurities that reduce its heating value to be used directly as fuel, hence, a need to enhance it by upgrading to bio-methane. Several techniques exist for upgrading biogas to bio-methane. This paper present four upgrading techniques; absorption, adsorption, membrane and cryogenic techniques, a brief theoretical background, advantages and operational issues associated with each technique.
- Full Text:
- Authors: Masebinu, S. O. , Aboyade, A. , Muzenda, Edison
- Date: 2014
- Subjects: Biogas , Biogas enrichment
- Type: Article
- Identifier: uj:4912 , ISSN 2349-1442 , http://hdl.handle.net/10210/13012
- Description: Biogas, a renewable energy, can be captured, upgraded and used to fuel a vehicle as an alternative to fossil fuel, thus, reducing greenhouse gas emission. Biogas is environmentally hazardous if emitted directly into the environment. Increasing demand for bio-methane to be used as vehicular fuel has called for efficient use of waste and technology that is optimal yet economical. Biogas in its raw state contains impurities that reduce its heating value to be used directly as fuel, hence, a need to enhance it by upgrading to bio-methane. Several techniques exist for upgrading biogas to bio-methane. This paper present four upgrading techniques; absorption, adsorption, membrane and cryogenic techniques, a brief theoretical background, advantages and operational issues associated with each technique.
- Full Text:
Evaluation of ceramic media wear characteristics on the M100 Isa Mill
- Makgamatha, Kgadi A., Mulaba-Bafubiandi, Antoine F., Randigwane, A., Bolha, W., Anyimadu, A.
- Authors: Makgamatha, Kgadi A. , Mulaba-Bafubiandi, Antoine F. , Randigwane, A. , Bolha, W. , Anyimadu, A.
- Date: 2014
- Subjects: Ceramic media , M100 Isa-Mill
- Type: Article
- Identifier: uj:4910 , ISSN 2349-1442 , http://hdl.handle.net/10210/13010
- Description: Since the installation of Isa-Mills, major improvements/studies have been made to make it more efficient. In 2006, ceramic media were introduced in the market to identify the cost effective type. This was achieved by the quality studies on different type of media both at the laboratory and pilot plant scale. In this present study, a 100 hours test was carried out in order to evaluate the wear characteristics of ceramic media branded candidate media and was compared to the standard media using the M100 Isa mill at the pilot plant. The evaluation was in the basis of comparing the relative performance of the candidate media and standard media in terms of wear rate, energy consumption and the finest of grind, whereby the following results were generated. A seasoned charge graph of both media at d80 μm vs. running time (hr) was generated and clearly highlighted the points of reaching seasoned charge for both media however, this didn’t help much in terms of finding the difference between the media because one cannot confirm the points of reaching seasoned charge by just looking at the graph but this can be confirmed by the actual size analysis of the media beads. A further comparison was made by comparing the finest of grinds from the Isa-Mill discharge and it does not necessarily gives a clear view of which media is better compared to the other. The media wear rate and energy consumption of both media were compared and the standard media showed a big variance from the candidate media in terms of wear and energy. The standard media stood out to be the cost-effective type compared to the candidate media. Its utilization in the plant will then be suggested.
- Full Text:
- Authors: Makgamatha, Kgadi A. , Mulaba-Bafubiandi, Antoine F. , Randigwane, A. , Bolha, W. , Anyimadu, A.
- Date: 2014
- Subjects: Ceramic media , M100 Isa-Mill
- Type: Article
- Identifier: uj:4910 , ISSN 2349-1442 , http://hdl.handle.net/10210/13010
- Description: Since the installation of Isa-Mills, major improvements/studies have been made to make it more efficient. In 2006, ceramic media were introduced in the market to identify the cost effective type. This was achieved by the quality studies on different type of media both at the laboratory and pilot plant scale. In this present study, a 100 hours test was carried out in order to evaluate the wear characteristics of ceramic media branded candidate media and was compared to the standard media using the M100 Isa mill at the pilot plant. The evaluation was in the basis of comparing the relative performance of the candidate media and standard media in terms of wear rate, energy consumption and the finest of grind, whereby the following results were generated. A seasoned charge graph of both media at d80 μm vs. running time (hr) was generated and clearly highlighted the points of reaching seasoned charge for both media however, this didn’t help much in terms of finding the difference between the media because one cannot confirm the points of reaching seasoned charge by just looking at the graph but this can be confirmed by the actual size analysis of the media beads. A further comparison was made by comparing the finest of grinds from the Isa-Mill discharge and it does not necessarily gives a clear view of which media is better compared to the other. The media wear rate and energy consumption of both media were compared and the standard media showed a big variance from the candidate media in terms of wear and energy. The standard media stood out to be the cost-effective type compared to the candidate media. Its utilization in the plant will then be suggested.
- Full Text:
Adsorption of Cu and Ni from AMD using activated bentonite
- Ntuli, Freeman, Falayi, Thabo, Molala, Panelope
- Authors: Ntuli, Freeman , Falayi, Thabo , Molala, Panelope
- Date: 2014
- Subjects: Bentonite , Copper adsorption , Langmuir kinetic models , Nickel adsorption
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/387938 , uj:4901 , ISSN 2349-1442 , http://hdl.handle.net/10210/12996
- Description: The ability of activated bentonite to adsorb Cu and Ni was investigated. 6 % solid loading was chosen as the optimum solid loading for activated bentonite with 94.85% Cu and 92.05% Ni removal after 3 hours of agitation. The adsorption process followed the Langmuir isotherm and pseudo second order kinetic models. The maximum adsorption capacities were 0.297 and 0.235 mg/g for Cu and Ni respectively. The adsorption of Cu and Ni was thermodynamically spontaneous. Cu adsorption was endothermic whilst Ni adsorption was exothermic. Activated bentonite could be used for two cycles of adsorption without regeneration.
- Full Text:
- Authors: Ntuli, Freeman , Falayi, Thabo , Molala, Panelope
- Date: 2014
- Subjects: Bentonite , Copper adsorption , Langmuir kinetic models , Nickel adsorption
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/387938 , uj:4901 , ISSN 2349-1442 , http://hdl.handle.net/10210/12996
- Description: The ability of activated bentonite to adsorb Cu and Ni was investigated. 6 % solid loading was chosen as the optimum solid loading for activated bentonite with 94.85% Cu and 92.05% Ni removal after 3 hours of agitation. The adsorption process followed the Langmuir isotherm and pseudo second order kinetic models. The maximum adsorption capacities were 0.297 and 0.235 mg/g for Cu and Ni respectively. The adsorption of Cu and Ni was thermodynamically spontaneous. Cu adsorption was endothermic whilst Ni adsorption was exothermic. Activated bentonite could be used for two cycles of adsorption without regeneration.
- Full Text:
Effect of moisture quantity on non-distillation oil extraction from SCG using methanol
- Mojapelo, Nancy, Mollagee, Mansoor, Muzenda, Edison, Mguni, Liberty L
- Authors: Mojapelo, Nancy , Mollagee, Mansoor , Muzenda, Edison , Mguni, Liberty L
- Date: 2014
- Subjects: Oil extraction , Methanol , Hexane , Spent coffee grounds
- Type: Article
- Identifier: uj:4902 , ISSN 2349-1442 , http://hdl.handle.net/10210/12997
- Description: Oil was extracted from spent coffee grounds using methanol. Methanol is not a popular solvent for oil extraction because of its toxicity but it is ideal for biodiesel production. The SCG was determined to contain 17.1 % wt% oil by extraction using hexane for 16h. The highest oil extraction 8.5 wt% was observed on a dry sample at a separation temperature of 25 ˚C representing only 50% recovery. Oil extraction was observed to depend on separation temperature and SCG water quantity. The extracted oil was characterised by a number of methods. Fourier-transform infrared spectroscopy (FTIR) results showed no difference in functional groups between hexane and methanol extracted oil. The Refractive Index (RI) results also suggested similarity in fatty acid chain length for oils extracted by these solvent. However, it was observed that oil extracted by hexane had higher amounts of FFA compared to methanol extracted oil.
- Full Text:
- Authors: Mojapelo, Nancy , Mollagee, Mansoor , Muzenda, Edison , Mguni, Liberty L
- Date: 2014
- Subjects: Oil extraction , Methanol , Hexane , Spent coffee grounds
- Type: Article
- Identifier: uj:4902 , ISSN 2349-1442 , http://hdl.handle.net/10210/12997
- Description: Oil was extracted from spent coffee grounds using methanol. Methanol is not a popular solvent for oil extraction because of its toxicity but it is ideal for biodiesel production. The SCG was determined to contain 17.1 % wt% oil by extraction using hexane for 16h. The highest oil extraction 8.5 wt% was observed on a dry sample at a separation temperature of 25 ˚C representing only 50% recovery. Oil extraction was observed to depend on separation temperature and SCG water quantity. The extracted oil was characterised by a number of methods. Fourier-transform infrared spectroscopy (FTIR) results showed no difference in functional groups between hexane and methanol extracted oil. The Refractive Index (RI) results also suggested similarity in fatty acid chain length for oils extracted by these solvent. However, it was observed that oil extracted by hexane had higher amounts of FFA compared to methanol extracted oil.
- Full Text:
- «
- ‹
- 1
- ›
- »