Design of a biodigester to treat cow dung in Botswana
- Valela, Innocent, Muzenda, Edison
- Authors: Valela, Innocent , Muzenda, Edison
- Date: 2019
- Subjects: Biogas , Cow dung , Design
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/403986 , uj:33871 , Citation: Valela, I. & Muzenda, E. 2019. Design of a biodigester to treat cow dung in Botswana.
- Description: Abstract: The biogas potential of Botswana, a cattle rich nation is explored using dung as a substrate. Biogas could be a good renewable and clean substitute for other forms of energy in rural Botswana, however, the technical and socio-economic potential remains largely unexploited. In this study, the cattle dung was characterized, followed by a lab-scale experiments on the biogas potential yields from the dung. The bio-digester design was selected using the multi criteria decision analysis. From the six digester models that were evaluated for selection, the KVIC was found to be the most suitable with its size ranging from 10 to 100 m3. The bio-digester was subsequently designed using data and mathematical models obtained from literature. The biogas plant was designed for Lemcke’s cattle farm, the best selected site, with 5000 herds. The feedstock was found to have an in-situ density of 1410 kg/m3 with a total solids (TS) content of 18.9%, volatile solids (TS) content of 80%. The suitable digester size was found to be 20 m3. An energy audit showed that the plant had a potential to produce a surplus of 45.3 MWh of energy annually.
- Full Text:
- Authors: Valela, Innocent , Muzenda, Edison
- Date: 2019
- Subjects: Biogas , Cow dung , Design
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/403986 , uj:33871 , Citation: Valela, I. & Muzenda, E. 2019. Design of a biodigester to treat cow dung in Botswana.
- Description: Abstract: The biogas potential of Botswana, a cattle rich nation is explored using dung as a substrate. Biogas could be a good renewable and clean substitute for other forms of energy in rural Botswana, however, the technical and socio-economic potential remains largely unexploited. In this study, the cattle dung was characterized, followed by a lab-scale experiments on the biogas potential yields from the dung. The bio-digester design was selected using the multi criteria decision analysis. From the six digester models that were evaluated for selection, the KVIC was found to be the most suitable with its size ranging from 10 to 100 m3. The bio-digester was subsequently designed using data and mathematical models obtained from literature. The biogas plant was designed for Lemcke’s cattle farm, the best selected site, with 5000 herds. The feedstock was found to have an in-situ density of 1410 kg/m3 with a total solids (TS) content of 18.9%, volatile solids (TS) content of 80%. The suitable digester size was found to be 20 m3. An energy audit showed that the plant had a potential to produce a surplus of 45.3 MWh of energy annually.
- Full Text:
Development and performance evaluation of a single stage travelling-wave thermo-acoustic generator
- Shamase, Halalisani, Spambo, Samkelo, Ngcukayitobi, Miniyenkosi, Tartibu, Lagouge, Bokoro, Pitchou
- Authors: Shamase, Halalisani , Spambo, Samkelo , Ngcukayitobi, Miniyenkosi , Tartibu, Lagouge , Bokoro, Pitchou
- Date: 2019
- Subjects: Thermo-acoustic , Travelling-wave , Design
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/401862 , uj:33605 , Citation: Shamase, H. et al. 2019. Development and performance evaluation of a single stage travelling-wave thermo-acoustic generator.
- Description: Abstract: Thermo-acoustic systems are being considered as a potential solution for electricity generation. This work describes the construction of a single stage travelling-wave thermo-acoustic generator. Secondly, an experimental investigation into the effect of the heat source on the potential of the device for electricity generation is performed. The magnitude of the sound generated by the engine, the onset time and the magnitude of electricity generated by the linear alternator have been considered as performance indicators for the device developed. This paper provides clarity on the potential for thermo-acoustic system for sound-to-electricity conversion. Clear trends showing the effect of inputs parameters on device performance have been disclosed. The minimum/maximum amount of heat that has produced a sound was 339/634oC corresponding to sound of 114.0/114.13 dB and a voltage of 278/319 mV. Although the efficiency of the sound-to-electricity conversion was low, this work proves the viability of thermo-acoustic as the alternative solution for electricity generation.
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- Authors: Shamase, Halalisani , Spambo, Samkelo , Ngcukayitobi, Miniyenkosi , Tartibu, Lagouge , Bokoro, Pitchou
- Date: 2019
- Subjects: Thermo-acoustic , Travelling-wave , Design
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/401862 , uj:33605 , Citation: Shamase, H. et al. 2019. Development and performance evaluation of a single stage travelling-wave thermo-acoustic generator.
- Description: Abstract: Thermo-acoustic systems are being considered as a potential solution for electricity generation. This work describes the construction of a single stage travelling-wave thermo-acoustic generator. Secondly, an experimental investigation into the effect of the heat source on the potential of the device for electricity generation is performed. The magnitude of the sound generated by the engine, the onset time and the magnitude of electricity generated by the linear alternator have been considered as performance indicators for the device developed. This paper provides clarity on the potential for thermo-acoustic system for sound-to-electricity conversion. Clear trends showing the effect of inputs parameters on device performance have been disclosed. The minimum/maximum amount of heat that has produced a sound was 339/634oC corresponding to sound of 114.0/114.13 dB and a voltage of 278/319 mV. Although the efficiency of the sound-to-electricity conversion was low, this work proves the viability of thermo-acoustic as the alternative solution for electricity generation.
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Design and construction of a thermoacoustically driven thermoacoustic refrigerator
- Alcock, A.C., Tartibu, L.K., Jen, T.C.
- Authors: Alcock, A.C. , Tartibu, L.K. , Jen, T.C.
- Date: 2017
- Subjects: Design , Thermoacoustic refrigeration , TADTAR
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/250780 , uj:26139 , Citation: Alcock, A.C., Tartibu, L.K. & Jen, T.C. 2017. Design and construction of a thermoacoustically driven thermoacoustic refrigerator.
- Description: Abstract: This work describes the design and construction of a standing wave Thermoacoustically Driven Thermoacoustic Refrigerator (TADTAR). The thermoacoustic cooler is proposed in this study as an alternative sustainable solution to current issues with vapor compression refrigerators, due to its environmentally friendlier attributes and its solar energy driven capabilities. However, one of the main hindrances to the expansion of this technology is its current lack of efficiency and performance closely related to the designing of the device. Hence, a model has been designed and constructed to perform an experimental investigation of the device’s performance at the University of Johannesburg. This model will mainly be used to investigate the dynamics of the TADTAR arrangement. The TADTAR consists of two thermoacoustic systems namely a thermoacoustic engine coupled to a thermoacoustic refrigerator. The thermoacoustic engine consists of a heat source and a cordierite honeycomb stack which converts heat into acoustic energy. The heat pumping takes place within a thermoacoustic refrigerator. Guidance on the material selection, constraints and calculation of the geometrical configuration describing the device constitute the main contribution of this work
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- Authors: Alcock, A.C. , Tartibu, L.K. , Jen, T.C.
- Date: 2017
- Subjects: Design , Thermoacoustic refrigeration , TADTAR
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/250780 , uj:26139 , Citation: Alcock, A.C., Tartibu, L.K. & Jen, T.C. 2017. Design and construction of a thermoacoustically driven thermoacoustic refrigerator.
- Description: Abstract: This work describes the design and construction of a standing wave Thermoacoustically Driven Thermoacoustic Refrigerator (TADTAR). The thermoacoustic cooler is proposed in this study as an alternative sustainable solution to current issues with vapor compression refrigerators, due to its environmentally friendlier attributes and its solar energy driven capabilities. However, one of the main hindrances to the expansion of this technology is its current lack of efficiency and performance closely related to the designing of the device. Hence, a model has been designed and constructed to perform an experimental investigation of the device’s performance at the University of Johannesburg. This model will mainly be used to investigate the dynamics of the TADTAR arrangement. The TADTAR consists of two thermoacoustic systems namely a thermoacoustic engine coupled to a thermoacoustic refrigerator. The thermoacoustic engine consists of a heat source and a cordierite honeycomb stack which converts heat into acoustic energy. The heat pumping takes place within a thermoacoustic refrigerator. Guidance on the material selection, constraints and calculation of the geometrical configuration describing the device constitute the main contribution of this work
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Design of a rice transplanter for Zimbabwean farmers
- Mushiri, Tawanda, Gutsa, Brighton, Mbohwa, Charles
- Authors: Mushiri, Tawanda , Gutsa, Brighton , Mbohwa, Charles
- Date: 2017
- Subjects: Rice transplanter , Musculosketal disorders , Design
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/239109 , uj:24558 , Citation: Mushiri, T., Gutsa, B. & Mbohwa, C. 2017. Design of a rice transplanter for Zimbabwean farmers.
- Description: Abstract: Rice is a crop of growing importance in Zimbabwe but with a production of only 700 metric tonnes. This is because in wetlands it is largely grown by broadcasting of seeds and seedlings; and manual transplanting of seedlings. In practicing the said method however, farmers are exposed to musculosketal disorders as well as back problems due to the repetitive bending as well as the awkward posture needed in performing the task. Though manual transplanting gives uniform crop stand it is quite expensive and requires lot of labour besides involving lot of drudgery. Singh et al., 1985 reported that transplanting takes about 250-300 man hours/ha which is roughly 25 per cent of the total labour requirement of the crop. The rice production in Zimbabwe has also been very low because the common rice types were affected by the local climatic conditions however in 2014 businessman and farmer struck a deal with renowned Chinese agricultural scientist for National Hybrid Rice Research and Development Centre in Changsha in Hunan Province to start a pilot hybrid rice production exercise that could easily transform Zimbabwe into a major rice growing hub in the SADC region using varieties suitable to local conditions. This paper aims to design an ergonomic rice transplanter suited for the Zimbabwean climate and terrain. The mechanical transplanting of rice has been considered the most promising option, as it saves labour, ensures timely transplanting and attains optimum plant density that contributes to high productivity. Mechanization of rice sector will lead to higher productivity with releasing of work force to other sectors.
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- Authors: Mushiri, Tawanda , Gutsa, Brighton , Mbohwa, Charles
- Date: 2017
- Subjects: Rice transplanter , Musculosketal disorders , Design
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/239109 , uj:24558 , Citation: Mushiri, T., Gutsa, B. & Mbohwa, C. 2017. Design of a rice transplanter for Zimbabwean farmers.
- Description: Abstract: Rice is a crop of growing importance in Zimbabwe but with a production of only 700 metric tonnes. This is because in wetlands it is largely grown by broadcasting of seeds and seedlings; and manual transplanting of seedlings. In practicing the said method however, farmers are exposed to musculosketal disorders as well as back problems due to the repetitive bending as well as the awkward posture needed in performing the task. Though manual transplanting gives uniform crop stand it is quite expensive and requires lot of labour besides involving lot of drudgery. Singh et al., 1985 reported that transplanting takes about 250-300 man hours/ha which is roughly 25 per cent of the total labour requirement of the crop. The rice production in Zimbabwe has also been very low because the common rice types were affected by the local climatic conditions however in 2014 businessman and farmer struck a deal with renowned Chinese agricultural scientist for National Hybrid Rice Research and Development Centre in Changsha in Hunan Province to start a pilot hybrid rice production exercise that could easily transform Zimbabwe into a major rice growing hub in the SADC region using varieties suitable to local conditions. This paper aims to design an ergonomic rice transplanter suited for the Zimbabwean climate and terrain. The mechanical transplanting of rice has been considered the most promising option, as it saves labour, ensures timely transplanting and attains optimum plant density that contributes to high productivity. Mechanization of rice sector will lead to higher productivity with releasing of work force to other sectors.
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Design of an electrically powered bending machine : case of Zimbabwe
- Mushiri, Tawanda, Shumba, Definite, Mbohwa, Charles
- Authors: Mushiri, Tawanda , Shumba, Definite , Mbohwa, Charles
- Date: 2017
- Subjects: Bending machine , Case study , Design
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/239089 , uj:24554 , Citation: Mushiri, T., Shumba, D. & Mbohwa, C. 2017. Design of an electrically powered bending machine : case of Zimbabwe.
- Description: Abstract: This paper seeks to carry out design of a small scale electrically powered bending machine for a developing nation, case for Zimbabwe. The bending of metal is of great importance in the manufacture of products such as nut shelling machines and maize shelling machines. Currently being used at Company X engineering is a manual bending machine with a single operation hence this design will help to increase the number of metals being bent, an increase in the efficiency and production. The paper deals with manufacturing or bending of sheet metal by using power operated sheet bending machine. Especially discussion made the productivity analysis of manually or power operated sheet bending machine. Considering manual operation is replaced by power operated devices. It also gives information about limitation of manually operated sheet bending machine and power operated sheet bending machine. The existing machines are limited to a single operation. The aim of the research is to increase the number of bent parts and to place an adjustable table to suit the height of the user thereby reducing back pain internal injuries in the long run. The researchers visited the Company X to gather information concerning the problems faced by the employees. Material tests which are of great value were carried out and the use of software. A Plate Rolling Machine is a machine that will roll different kinds of metal sheet into a round or conical shape and a rod bending machine will roll or bend different kinds of metal sheet into right angles or circular shapes. The research aims at making it possible to do the operations on a single machine. We recommend the machine to be automated and the use of a servo motor to reduce human injuries at the workshop. Use of oils and maintenance is of great value to increase the life span of the machine.
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- Authors: Mushiri, Tawanda , Shumba, Definite , Mbohwa, Charles
- Date: 2017
- Subjects: Bending machine , Case study , Design
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/239089 , uj:24554 , Citation: Mushiri, T., Shumba, D. & Mbohwa, C. 2017. Design of an electrically powered bending machine : case of Zimbabwe.
- Description: Abstract: This paper seeks to carry out design of a small scale electrically powered bending machine for a developing nation, case for Zimbabwe. The bending of metal is of great importance in the manufacture of products such as nut shelling machines and maize shelling machines. Currently being used at Company X engineering is a manual bending machine with a single operation hence this design will help to increase the number of metals being bent, an increase in the efficiency and production. The paper deals with manufacturing or bending of sheet metal by using power operated sheet bending machine. Especially discussion made the productivity analysis of manually or power operated sheet bending machine. Considering manual operation is replaced by power operated devices. It also gives information about limitation of manually operated sheet bending machine and power operated sheet bending machine. The existing machines are limited to a single operation. The aim of the research is to increase the number of bent parts and to place an adjustable table to suit the height of the user thereby reducing back pain internal injuries in the long run. The researchers visited the Company X to gather information concerning the problems faced by the employees. Material tests which are of great value were carried out and the use of software. A Plate Rolling Machine is a machine that will roll different kinds of metal sheet into a round or conical shape and a rod bending machine will roll or bend different kinds of metal sheet into right angles or circular shapes. The research aims at making it possible to do the operations on a single machine. We recommend the machine to be automated and the use of a servo motor to reduce human injuries at the workshop. Use of oils and maintenance is of great value to increase the life span of the machine.
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Development of a twin screw extruder
- Sobowale, Sunday Samuel, Adebo, Oluwafemi Ayodeji, Adebiyi, Janet Adeyinka
- Authors: Sobowale, Sunday Samuel , Adebo, Oluwafemi Ayodeji , Adebiyi, Janet Adeyinka
- Date: 2017
- Subjects: Extrusion , Twin screw extruder , Design
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/262072 , uj:27666 , Citation: Sobowale, S.S., Adebo, O.A. & Adebiyi, J.A. 2017. Development of a twin screw extruder. Agricultural Engineering International: CIGR Journal, 19(4): 181–186.
- Description: Abstract: The aim of this study was to design, construct a multi-purpose twin screw extruder and evaluate its performance. All parts of the extruder were constructed using locally available materials and was made suitable for both batch and continuous production. The extruder essentially consists of the hopper, barrel, variable screw speed and temperature control, electrical motor and replaceable dies to give different sizes and shapes in the final products. It could also handle feed materials of different rheology. Performance evaluation of the extruder was done using cocoyam flour, varying feed moisture content (FMC) and screw speed (SS). Both the FMC and SS were observed to significantly affect all performance indicators (expansion ratio, residence time, throughput and functional efficiency) of the extrusion process. The availability and efficient access to this equipment would encourage the development of locally made extruded products. Through effective utilization, it is expected that the extruder would expand the production and processing of extruded foods.
- Full Text:
- Authors: Sobowale, Sunday Samuel , Adebo, Oluwafemi Ayodeji , Adebiyi, Janet Adeyinka
- Date: 2017
- Subjects: Extrusion , Twin screw extruder , Design
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/262072 , uj:27666 , Citation: Sobowale, S.S., Adebo, O.A. & Adebiyi, J.A. 2017. Development of a twin screw extruder. Agricultural Engineering International: CIGR Journal, 19(4): 181–186.
- Description: Abstract: The aim of this study was to design, construct a multi-purpose twin screw extruder and evaluate its performance. All parts of the extruder were constructed using locally available materials and was made suitable for both batch and continuous production. The extruder essentially consists of the hopper, barrel, variable screw speed and temperature control, electrical motor and replaceable dies to give different sizes and shapes in the final products. It could also handle feed materials of different rheology. Performance evaluation of the extruder was done using cocoyam flour, varying feed moisture content (FMC) and screw speed (SS). Both the FMC and SS were observed to significantly affect all performance indicators (expansion ratio, residence time, throughput and functional efficiency) of the extrusion process. The availability and efficient access to this equipment would encourage the development of locally made extruded products. Through effective utilization, it is expected that the extruder would expand the production and processing of extruded foods.
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Broadening access to problem-based learning : design of the shell eco-marathon car-in-a-box concept
- Von Solms, S., Hurter, W.S., Meyer, J.
- Authors: Von Solms, S. , Hurter, W.S. , Meyer, J.
- Date: 2016
- Subjects: Car-In-A-Box , Design , Problem-based learning
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/124144 , uj:20879 , Citation: Von Solms, S., Hurter, W.S & Meyer, J. 2016. Broadening access to problem-based learning : design of the shell eco-marathon car-in-a-box concept.
- Description: Abstract: Problem-based learning has proven to develop teamwork, problem solving skills, communication and critical thinking skills amongst learners. Due to these advantages, secondary schools in South Africa engage with problem-based events to promote the participation of learners in Science, Technology, Engineering and Mathematics (STEM). However, many schools face lack of time, lack of available funds and lack of the required technical skill set, which limits them from participating in these events. The Car-In-a-Box concept was developed to broaden access to a STEM problem-based learning event, called the Shell Eco-Marathon. The Car-In-A-Box concept addresses the three challenges that would normally prevent a school from entering the Shell Eco-Marathon, disenabling learners to harness the advantages of problem-based learning. The impact of the Car-In-A-Box concept for broadening access to problem-based learning is discussed.
- Full Text:
- Authors: Von Solms, S. , Hurter, W.S. , Meyer, J.
- Date: 2016
- Subjects: Car-In-A-Box , Design , Problem-based learning
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/124144 , uj:20879 , Citation: Von Solms, S., Hurter, W.S & Meyer, J. 2016. Broadening access to problem-based learning : design of the shell eco-marathon car-in-a-box concept.
- Description: Abstract: Problem-based learning has proven to develop teamwork, problem solving skills, communication and critical thinking skills amongst learners. Due to these advantages, secondary schools in South Africa engage with problem-based events to promote the participation of learners in Science, Technology, Engineering and Mathematics (STEM). However, many schools face lack of time, lack of available funds and lack of the required technical skill set, which limits them from participating in these events. The Car-In-a-Box concept was developed to broaden access to a STEM problem-based learning event, called the Shell Eco-Marathon. The Car-In-A-Box concept addresses the three challenges that would normally prevent a school from entering the Shell Eco-Marathon, disenabling learners to harness the advantages of problem-based learning. The impact of the Car-In-A-Box concept for broadening access to problem-based learning is discussed.
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Design of a mechanical cleaning device P.I.G (pipeline intervention gadget) connecting two transfer lines in Zimbabwe
- Mushiri, Tawanda, Ndlovu, Stephen, Mbohwa, Charles
- Authors: Mushiri, Tawanda , Ndlovu, Stephen , Mbohwa, Charles
- Date: 2016
- Subjects: Pipeline intervention gadget , Pipeline , Design
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/213988 , uj:21222 , Citation: Mushiri, T., Ndlovu, S & Mbohwa, C. 2016. Design of a mechanical cleaning device P.I.G (pipeline intervention gadget) connecting two transfer lines in Zimbabwe.
- Description: Abstract: In the Oil and Gas Industry, maintenance is done using a device or tool called a pig, chiefly to remove solids, dirt, and liquids from the pipelines. The aim of this work is to design and retrofit a pig which will clean 3 identical underground transfer pipelines linking 2 depots The movement of this tool is basically through the action of the fluid in the pipeline pushing it along as it is pumped from one point to another, hence no external power is needed in the device to help in its movement. Calculation based model analysis of the tool together with Solidworks simulations and results are included in detail, with all assumptions and limitations clearly stated and listed. The results show that the pig will move inside the pipe at a lower speed than the mean flow velocity which is good for the performance of the electronic systems installed on its body for pipeline inspection. Bypass hole is added on the central part of the pig body to control the speed as well as keep the cleaned dirt stirred and moving, being pushed by the pig as it performs its cleaning process.
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- Authors: Mushiri, Tawanda , Ndlovu, Stephen , Mbohwa, Charles
- Date: 2016
- Subjects: Pipeline intervention gadget , Pipeline , Design
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/213988 , uj:21222 , Citation: Mushiri, T., Ndlovu, S & Mbohwa, C. 2016. Design of a mechanical cleaning device P.I.G (pipeline intervention gadget) connecting two transfer lines in Zimbabwe.
- Description: Abstract: In the Oil and Gas Industry, maintenance is done using a device or tool called a pig, chiefly to remove solids, dirt, and liquids from the pipelines. The aim of this work is to design and retrofit a pig which will clean 3 identical underground transfer pipelines linking 2 depots The movement of this tool is basically through the action of the fluid in the pipeline pushing it along as it is pumped from one point to another, hence no external power is needed in the device to help in its movement. Calculation based model analysis of the tool together with Solidworks simulations and results are included in detail, with all assumptions and limitations clearly stated and listed. The results show that the pig will move inside the pipe at a lower speed than the mean flow velocity which is good for the performance of the electronic systems installed on its body for pipeline inspection. Bypass hole is added on the central part of the pig body to control the speed as well as keep the cleaned dirt stirred and moving, being pushed by the pig as it performs its cleaning process.
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Multi-criteria analysis of different technologies for the bioenergy recovery from OFMSW
- Matheri, Anthony Njuguna, Mbohwa, Charles, Belaid, Mohamed, Seodigeng, Tumisang, Ngila, Jane Catherine
- Authors: Matheri, Anthony Njuguna , Mbohwa, Charles , Belaid, Mohamed , Seodigeng, Tumisang , Ngila, Jane Catherine
- Date: 2016
- Subjects: Anaerobic digester , Design , Bioenergy recovery
- Language: English
- Type: Conference proceedings
- Identifier: http://ujcontent.uj.ac.za8080/10210/377197 , http://hdl.handle.net/10210/214131 , uj:21242 , Citation: Matheri, A.N. et al. 2016. Multi-criteria analysis of different technologies for the bioenergy recovery from OFMSW.
- Description: Abstract: In this study, the multi-criteria analysis model is demonstrated for evaluation and technologies from municipal solid waste (MSW) in City of Johannesburg (CoJ), South Africa. The technologies evaluation and alternation criteria for multi-criteria decision analysis (MCDA) area characterized by reviewing the literature and consulting experts in the renewable energy and waste management. MCDA was the approach employed by decision makers to make recommendation on technique employed to select the most suitable biogas digester technology for organic fraction of municipal solid waste (OFMWS) originating from the city’s landfills base on scalability, relative cost prices, available, temperature regulation, agitation, ease of construction, operation and maintenance. The result for digester type indicated that the “complete mix, continuously stirred anaerobic digester” (CSAD) was preferred with 79% preference to other anaerobic digester technologies for energy recovery.
- Full Text:
- Authors: Matheri, Anthony Njuguna , Mbohwa, Charles , Belaid, Mohamed , Seodigeng, Tumisang , Ngila, Jane Catherine
- Date: 2016
- Subjects: Anaerobic digester , Design , Bioenergy recovery
- Language: English
- Type: Conference proceedings
- Identifier: http://ujcontent.uj.ac.za8080/10210/377197 , http://hdl.handle.net/10210/214131 , uj:21242 , Citation: Matheri, A.N. et al. 2016. Multi-criteria analysis of different technologies for the bioenergy recovery from OFMSW.
- Description: Abstract: In this study, the multi-criteria analysis model is demonstrated for evaluation and technologies from municipal solid waste (MSW) in City of Johannesburg (CoJ), South Africa. The technologies evaluation and alternation criteria for multi-criteria decision analysis (MCDA) area characterized by reviewing the literature and consulting experts in the renewable energy and waste management. MCDA was the approach employed by decision makers to make recommendation on technique employed to select the most suitable biogas digester technology for organic fraction of municipal solid waste (OFMWS) originating from the city’s landfills base on scalability, relative cost prices, available, temperature regulation, agitation, ease of construction, operation and maintenance. The result for digester type indicated that the “complete mix, continuously stirred anaerobic digester” (CSAD) was preferred with 79% preference to other anaerobic digester technologies for energy recovery.
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Optimal design study of thermoacoustic regenerator with lexicographic optimization method
- Tartibu, L.K., Sun, B., Kaunda, M.A.E.
- Authors: Tartibu, L.K. , Sun, B. , Kaunda, M.A.E.
- Date: 2015
- Subjects: Design , Implementing , Managing and practicing innovation , Optimization algorithms , Mechanical design , Modelling , Multi-objective/attribute decision-making , Design strategies
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/17471 , uj:15887 , ISSN: 1726-0531 , Citation: Tartibu, L.K. Sun, B. & Kaunda, M.A.E. 2015. Optimal design study of thermoacoustic regenerator with lexicographic optimization method. Journal of Engineering, Design and Technology, 13(3): 499 – 519. , DOI: 10.1108/JEDT-09-2012-0039.
- Description: Abstract: Purpose – This paper aims to illustrate the use of the augmented epsilon-constraint method implemented in general algebraic modelling system (GAMS), aimed at optimizing the geometry of a thermoacoustic regenerator. Thermoacoustic heat engines provide a practical solution to the problem of heat management where heat can be pumped or spot cooling can be produced. However, the most inhibiting characteristic of thermoacoustic cooling is their current lack of efficiencies. Design/methodology/approach – Lexicographic optimization is presented as an alternative optimization technique to the common used weighting methods. This approach establishes a hierarchical order among all the optimization objectives instead of giving them a specific (and most of the time, arbitrary) weight. Findings – A practical example is given, in a hypothetical scenario, showing how the proposed optimization technique may help thermoacoustic regenerator designers to identify Pareto optimal solutions when dealing with geometric parameters. This study highlights the fact that the geometrical parameters are interdependent, which support the use of a multi-objective approach for optimization in thermoacoustic. Originality/value – The research output from this paper can be a valuable resource to support designers in building efficient thermoacoustic device. The research illustrates the use of a lexicographic optimization to provide more meaningful results describing the geometry of thermoacoustic regenerator. It applies the epsilon-constraint method (AUGMENCON) to solve a five-criteria mixed integer non-linear problem implemented in GAMS (GAM software).
- Full Text:
- Authors: Tartibu, L.K. , Sun, B. , Kaunda, M.A.E.
- Date: 2015
- Subjects: Design , Implementing , Managing and practicing innovation , Optimization algorithms , Mechanical design , Modelling , Multi-objective/attribute decision-making , Design strategies
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/17471 , uj:15887 , ISSN: 1726-0531 , Citation: Tartibu, L.K. Sun, B. & Kaunda, M.A.E. 2015. Optimal design study of thermoacoustic regenerator with lexicographic optimization method. Journal of Engineering, Design and Technology, 13(3): 499 – 519. , DOI: 10.1108/JEDT-09-2012-0039.
- Description: Abstract: Purpose – This paper aims to illustrate the use of the augmented epsilon-constraint method implemented in general algebraic modelling system (GAMS), aimed at optimizing the geometry of a thermoacoustic regenerator. Thermoacoustic heat engines provide a practical solution to the problem of heat management where heat can be pumped or spot cooling can be produced. However, the most inhibiting characteristic of thermoacoustic cooling is their current lack of efficiencies. Design/methodology/approach – Lexicographic optimization is presented as an alternative optimization technique to the common used weighting methods. This approach establishes a hierarchical order among all the optimization objectives instead of giving them a specific (and most of the time, arbitrary) weight. Findings – A practical example is given, in a hypothetical scenario, showing how the proposed optimization technique may help thermoacoustic regenerator designers to identify Pareto optimal solutions when dealing with geometric parameters. This study highlights the fact that the geometrical parameters are interdependent, which support the use of a multi-objective approach for optimization in thermoacoustic. Originality/value – The research output from this paper can be a valuable resource to support designers in building efficient thermoacoustic device. The research illustrates the use of a lexicographic optimization to provide more meaningful results describing the geometry of thermoacoustic regenerator. It applies the epsilon-constraint method (AUGMENCON) to solve a five-criteria mixed integer non-linear problem implemented in GAMS (GAM software).
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The role of 6Ds : density, diversity, design, destination, distance, and demand management in transit oriented development (TOD)
- Ogra, Aurobindo, Ndebele, Robert
- Authors: Ogra, Aurobindo , Ndebele, Robert
- Date: 2014
- Subjects: Transit oriented development , Density , Demand management , Design , Diversity , Distance
- Type: Article
- Identifier: uj:5017 , http://hdl.handle.net/10210/13157
- Description: This paper reflects on the efficacy of Transit Oriented Development (TOD) and the primary components that constitute it. These components are widely recognized as manifesting themselves through the concept of “6Ds": Design, Diversity, Density, Distance, Destination, and Demand management. The paper thus investigates the main aspects that underlie these “Ds" and how they can equally be taken up in TOD initiatives. The development of efficient and sustainable transport systems has become a key mitigation method for major traffic problems such as congestion, poor mobility and access to services, as well as greenhouse gas emissions. The primary argument of this papercentres on the premise that the application of “6Ds" through TOD can go a long way in addressing current challenges thatconfront urban transport within cities. Using a case study, the paper contextualizes one of the “6Ds" and subsequent conclusions are drawn thereof in the form of key determinants.
- Full Text:
- Authors: Ogra, Aurobindo , Ndebele, Robert
- Date: 2014
- Subjects: Transit oriented development , Density , Demand management , Design , Diversity , Distance
- Type: Article
- Identifier: uj:5017 , http://hdl.handle.net/10210/13157
- Description: This paper reflects on the efficacy of Transit Oriented Development (TOD) and the primary components that constitute it. These components are widely recognized as manifesting themselves through the concept of “6Ds": Design, Diversity, Density, Distance, Destination, and Demand management. The paper thus investigates the main aspects that underlie these “Ds" and how they can equally be taken up in TOD initiatives. The development of efficient and sustainable transport systems has become a key mitigation method for major traffic problems such as congestion, poor mobility and access to services, as well as greenhouse gas emissions. The primary argument of this papercentres on the premise that the application of “6Ds" through TOD can go a long way in addressing current challenges thatconfront urban transport within cities. Using a case study, the paper contextualizes one of the “6Ds" and subsequent conclusions are drawn thereof in the form of key determinants.
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