Design of the bio-digester for biogas production : review
- Ramatsa, Ishmael M., Akinlabi, Esther Titilayo, Madyira, Daniel M., Huberts, Robert
- Authors: Ramatsa, Ishmael M. , Akinlabi, Esther Titilayo , Madyira, Daniel M. , Huberts, Robert
- Date: 2014
- Subjects: Biogas digesters
- Type: Article
- Identifier: uj:5016 , http://hdl.handle.net/10210/13156
- Description: This review is a summary of different aspects of the design and operation of biogas digesters. Three types of digesters were reviewed, that is, the plug flow, floating drum and the fixed dome digester. Biogas is one of the products formed during the anaerobic digestion process. Anaerobic digestion is dependent on several factors such as the pH value, feeding material, temperature, pressure, organic loading rate, retention time and the Carbon-to-Nitrogen (C/N) ratio. The shape of the digester and the material for construction are also considered important during design stage.
- Full Text:
- Authors: Ramatsa, Ishmael M. , Akinlabi, Esther Titilayo , Madyira, Daniel M. , Huberts, Robert
- Date: 2014
- Subjects: Biogas digesters
- Type: Article
- Identifier: uj:5016 , http://hdl.handle.net/10210/13156
- Description: This review is a summary of different aspects of the design and operation of biogas digesters. Three types of digesters were reviewed, that is, the plug flow, floating drum and the fixed dome digester. Biogas is one of the products formed during the anaerobic digestion process. Anaerobic digestion is dependent on several factors such as the pH value, feeding material, temperature, pressure, organic loading rate, retention time and the Carbon-to-Nitrogen (C/N) ratio. The shape of the digester and the material for construction are also considered important during design stage.
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Low pressure binder-less densification of fibrous biomass material using a screw press
- Pilusa, Tsietsi J., Huberts, Robert, Muzenda, Edison
- Authors: Pilusa, Tsietsi J. , Huberts, Robert , Muzenda, Edison
- Date: 2012
- Subjects: Biomass fuel , Fuel briquettes
- Type: Article
- Identifier: uj:6039 , http://hdl.handle.net/10210/10439
- Description: In this study, the theoretical relationship between pressure and density was investigated on cylindrical hollow fuel briquettes produced of a mixture of fibrous biomass material using a screw press without any chemical binder. The fuel briquettes were made of biomass and other waste material such as spent coffee beans, mielie husks, saw dust and coal fines under pressures of 0.878-2.2 Mega Pascals (MPa). The material was densified into briquettes of outer diameter of 100mm, inner diameter of 35mm and 50mm long. It was observed that manual screw compression action produces briquettes of relatively low density as compared to the ones made using hydraulic compression action. The pressure and density relationship was obtained in the form of power law and compare well with other cylindrical solid briquettes made using hydraulic compression action. The produced briquettes have a dry density of 989 kg/m3 and contain 26.30% fixed carbon, 39.34% volatile matter, 10.9% moisture and 10.46% ash as per dry proximate analysis. The bomb calorimeter tests have shown the briquettes yielding a gross calorific value of 18.9MJ/kg.
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- Authors: Pilusa, Tsietsi J. , Huberts, Robert , Muzenda, Edison
- Date: 2012
- Subjects: Biomass fuel , Fuel briquettes
- Type: Article
- Identifier: uj:6039 , http://hdl.handle.net/10210/10439
- Description: In this study, the theoretical relationship between pressure and density was investigated on cylindrical hollow fuel briquettes produced of a mixture of fibrous biomass material using a screw press without any chemical binder. The fuel briquettes were made of biomass and other waste material such as spent coffee beans, mielie husks, saw dust and coal fines under pressures of 0.878-2.2 Mega Pascals (MPa). The material was densified into briquettes of outer diameter of 100mm, inner diameter of 35mm and 50mm long. It was observed that manual screw compression action produces briquettes of relatively low density as compared to the ones made using hydraulic compression action. The pressure and density relationship was obtained in the form of power law and compare well with other cylindrical solid briquettes made using hydraulic compression action. The produced briquettes have a dry density of 989 kg/m3 and contain 26.30% fixed carbon, 39.34% volatile matter, 10.9% moisture and 10.46% ash as per dry proximate analysis. The bomb calorimeter tests have shown the briquettes yielding a gross calorific value of 18.9MJ/kg.
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Emissions analysis from combustion of eco-fuel briquettes for domestic application
- Pilusa, Jefrey, Muzenda, Edison, Huberts, Robert
- Authors: Pilusa, Jefrey , Muzenda, Edison , Huberts, Robert
- Date: 2013
- Subjects: Biomass fuel , Eco-fuel briquettes , Flue gas emissions
- Type: Article
- Identifier: uj:4842 , http://hdl.handle.net/10210/12490
- Description: In this study, flue gas emissions from the combustion of eco-fuel briquettes in a ceramic lined stove were investigated. The eco-fuel briquettes were made of biomass and other waste material such as spent coffee beans, mealie husks, saw dust and coal fines using a hand operated screw press. A combustion set-up consisting of digital weightometer, ceramic lined stove and a complete chimney system was used. The emissions from the combustion process were measured using a Testo 350 gas analyzer linked to the chimney system. The eco-briquettes made from a mixture of waste biomass burnt cleanly within the acceptable exposure limits as set out by Occupational Safety and Health Agency (OSHA). The measured gross calorific value was 18.9MJ/kg with a burning rate of 2g/min. These properties make eco-fuel briquettes suitable for domestic applications.
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- Authors: Pilusa, Jefrey , Muzenda, Edison , Huberts, Robert
- Date: 2013
- Subjects: Biomass fuel , Eco-fuel briquettes , Flue gas emissions
- Type: Article
- Identifier: uj:4842 , http://hdl.handle.net/10210/12490
- Description: In this study, flue gas emissions from the combustion of eco-fuel briquettes in a ceramic lined stove were investigated. The eco-fuel briquettes were made of biomass and other waste material such as spent coffee beans, mealie husks, saw dust and coal fines using a hand operated screw press. A combustion set-up consisting of digital weightometer, ceramic lined stove and a complete chimney system was used. The emissions from the combustion process were measured using a Testo 350 gas analyzer linked to the chimney system. The eco-briquettes made from a mixture of waste biomass burnt cleanly within the acceptable exposure limits as set out by Occupational Safety and Health Agency (OSHA). The measured gross calorific value was 18.9MJ/kg with a burning rate of 2g/min. These properties make eco-fuel briquettes suitable for domestic applications.
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Microalgae as a biocathode and feedstock in anode chamber for a selfsustainable microbial fuel cell technology : a review
- Mekuto, Lukhanyo, Olowaolafe, Ayomide V.A., Pandit, Soumya, Dyantyi, Noluntu, Nomngongo, Philiswa, Huberts, Robert
- Authors: Mekuto, Lukhanyo , Olowaolafe, Ayomide V.A. , Pandit, Soumya , Dyantyi, Noluntu , Nomngongo, Philiswa , Huberts, Robert
- Date: 2020
- Subjects: Algae , Anaerobic bacteria , Carbon dioxide
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/434081 , uj:37558 , Mekuto, L., et al. 2020: Microalgae as a biocathode and feedstock in anode chamber for a selfsustainable microbial fuel cell technology : a review.
- Description: Abstract: , Microbial fuel cell (MFC) technology has been investigated for over a decade now and it has been deemed as a preferred technique for energy generation since it is environmentally benign and does not produce toxic by/end products. However, this technology is characterized by low power outputs, poor microbial diversity detection, and the presence of methanogenic microorganisms, poor electrochemically active microorganisms’ enrichment techniques, and the type of electrode that is used, amongst others. Furthermore, this technology has relied mostly on refined chemicals for energy production and this practice is not sustainable for long-term application of this technology. This paper reviews the use of a microalgae-assisted MFC for a self-sustainable microbial fuel cell where a microalgae-assisted cathode is established to facilitate the oxidation/reduction reactions (ORR) while recycling the generated algal biomass to the anode compartment as a feedstock for improved energy generation. Furthermore, this review proposes for the utilization of cell disruption techniques to maximize nutrient availability for maximal power generation while also making use of molecular diagnostic tools such as metagenomics and metatranscriptomics to monitor the microbial community structure and function.
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- Authors: Mekuto, Lukhanyo , Olowaolafe, Ayomide V.A. , Pandit, Soumya , Dyantyi, Noluntu , Nomngongo, Philiswa , Huberts, Robert
- Date: 2020
- Subjects: Algae , Anaerobic bacteria , Carbon dioxide
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/434081 , uj:37558 , Mekuto, L., et al. 2020: Microalgae as a biocathode and feedstock in anode chamber for a selfsustainable microbial fuel cell technology : a review.
- Description: Abstract: , Microbial fuel cell (MFC) technology has been investigated for over a decade now and it has been deemed as a preferred technique for energy generation since it is environmentally benign and does not produce toxic by/end products. However, this technology is characterized by low power outputs, poor microbial diversity detection, and the presence of methanogenic microorganisms, poor electrochemically active microorganisms’ enrichment techniques, and the type of electrode that is used, amongst others. Furthermore, this technology has relied mostly on refined chemicals for energy production and this practice is not sustainable for long-term application of this technology. This paper reviews the use of a microalgae-assisted MFC for a self-sustainable microbial fuel cell where a microalgae-assisted cathode is established to facilitate the oxidation/reduction reactions (ORR) while recycling the generated algal biomass to the anode compartment as a feedstock for improved energy generation. Furthermore, this review proposes for the utilization of cell disruption techniques to maximize nutrient availability for maximal power generation while also making use of molecular diagnostic tools such as metagenomics and metatranscriptomics to monitor the microbial community structure and function.
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Can video (created with PowerPoint and TTSAPP) replace “Normal” lectures?
- Authors: Huberts, Robert
- Date: 2017
- Subjects: PowerPoint , Online Lecture , TTSAPP
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/244802 , uj:25316 , Citation: Huberts, R. 2017. Can video (created with PowerPoint and TTSAPP) replace “Normal” lectures?.
- Description: Abstract: PowerPoint, a ubiquitous tool used by lecturers and customizable with animation and now with video producing possibilities, and Microsoft Text to Speech Application (SAP15 TTSAPP), now including the more naturally sounding voices of Zira and David, have facilitated the setting up of a video lecture on boiling and condensation, which was presented to a class of 45 fourth year chemical engineering students in a computer laboratory. The original PowerPoint lecture on boiling and condensation was used in this study, and augmented with additional animation and audio to simulate normal lecture practice. The audio was produced by typing the spoken words into the notes section of the Power- Point slides, and processing these with the TTSAPP. The resulting audio wav files were then included in the sequence on the animation pane, and the presentation saved (also) as a MP4 file video. Students rated the video lecture relative to a normal lecture and supplied additional, mostly positive, comments, and these results are discussed and compared to their performance in the following test. Hence it was concluded that there are initial indications that the learning of students is not adversely affected by having lectures online. This can now be tested for a whole subject, after which one may start thinking of collaboration with other universities to ultimately aim for increased teaching efficiency.
- Full Text:
- Authors: Huberts, Robert
- Date: 2017
- Subjects: PowerPoint , Online Lecture , TTSAPP
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/244802 , uj:25316 , Citation: Huberts, R. 2017. Can video (created with PowerPoint and TTSAPP) replace “Normal” lectures?.
- Description: Abstract: PowerPoint, a ubiquitous tool used by lecturers and customizable with animation and now with video producing possibilities, and Microsoft Text to Speech Application (SAP15 TTSAPP), now including the more naturally sounding voices of Zira and David, have facilitated the setting up of a video lecture on boiling and condensation, which was presented to a class of 45 fourth year chemical engineering students in a computer laboratory. The original PowerPoint lecture on boiling and condensation was used in this study, and augmented with additional animation and audio to simulate normal lecture practice. The audio was produced by typing the spoken words into the notes section of the Power- Point slides, and processing these with the TTSAPP. The resulting audio wav files were then included in the sequence on the animation pane, and the presentation saved (also) as a MP4 file video. Students rated the video lecture relative to a normal lecture and supplied additional, mostly positive, comments, and these results are discussed and compared to their performance in the following test. Hence it was concluded that there are initial indications that the learning of students is not adversely affected by having lectures online. This can now be tested for a whole subject, after which one may start thinking of collaboration with other universities to ultimately aim for increased teaching efficiency.
- Full Text:
Taking teaching and learning online : a sequential mixed-methods study of an online chemical engineering module
- Authors: Huberts, Robert
- Date: 2019
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/400062 , uj:33372 , Citation: Huberts, R. 2019. Taking teaching and learning online : a sequential mixed-methods study of an online chemical engineering module.
- Description: Abstract: About 60 second year chemical engineering students were presented with segmented PowerPoint files (with TTS voice and extra animation to simulate lecturing) also saved as MPEG-4 videos in the presence of two tutors during all timetabled lectures of a course instead of lecturer face-to-face. Each segment was followed by questions comprehensively covering content, tutorial questions if applicable, and a question about the next lecture. A learning outcome poorly reached in the first test was identified and linked to the segment where content could be improved, exemplifying a feedback loop of potential use. Module passes and distinctions were compared to those of the past. Perceptions of students were quantified from standard teaching evaluation question statements, as well as an optional open-ended question. To further analyse student perceptions and suggestions qualitatively, three individual student interviews were conducted, resulting in a better impression on how to improve the online setup for future use.
- Full Text:
- Authors: Huberts, Robert
- Date: 2019
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/400062 , uj:33372 , Citation: Huberts, R. 2019. Taking teaching and learning online : a sequential mixed-methods study of an online chemical engineering module.
- Description: Abstract: About 60 second year chemical engineering students were presented with segmented PowerPoint files (with TTS voice and extra animation to simulate lecturing) also saved as MPEG-4 videos in the presence of two tutors during all timetabled lectures of a course instead of lecturer face-to-face. Each segment was followed by questions comprehensively covering content, tutorial questions if applicable, and a question about the next lecture. A learning outcome poorly reached in the first test was identified and linked to the segment where content could be improved, exemplifying a feedback loop of potential use. Module passes and distinctions were compared to those of the past. Perceptions of students were quantified from standard teaching evaluation question statements, as well as an optional open-ended question. To further analyse student perceptions and suggestions qualitatively, three individual student interviews were conducted, resulting in a better impression on how to improve the online setup for future use.
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OBE formative assessment as a tool to improve learner throughput
- Authors: Huberts, Robert
- Date: 2008
- Subjects: Chemical engineering technology , National Curriculum Statement - South Africa , Outcomes Based Education (OBE)
- Type: Article
- Identifier: uj:4789 , http://hdl.handle.net/10210/11972
- Description: According to data for 2005 retrieved from the South African Department of Education internet site, 3574.5 learners were registered nationally for ND in the Chemical Engineering Technology field, while 278.33 diplomas were issued, which translates into a graduation rate (throughput ratio) of 8%. This can be compared to a 100% pass rate, where the graduation rate is 33%. The SA YEARBOOK 2007/08 | EDUCATION contains the National Curriculum Statement (NCS) for schools, which is built on a number of principles including Outcomes Based Education (OBE). In 2008, school pupils are expected to write the National Senior Certificate examination. Although the National Plan for Higher Education (2001) does not mention OBE, academics in higher education institutions have been required to convert their study guides to OBE format and some (including the author) have received training in OBE to become assessors. A preliminary study was performed at UJ in 2006 to gauge whether OBE methods could be implemented for large groups of learners. A test had been written that most learners found challenging, leading to a high failure rate. A supplementary assessment strategy based on OBE Formative Assessment was conceptualised to allow learners to improve their marks. The main findings of the preliminary study were that a large number of learners could be accommodated in the Formative Assessments
- Full Text:
- Authors: Huberts, Robert
- Date: 2008
- Subjects: Chemical engineering technology , National Curriculum Statement - South Africa , Outcomes Based Education (OBE)
- Type: Article
- Identifier: uj:4789 , http://hdl.handle.net/10210/11972
- Description: According to data for 2005 retrieved from the South African Department of Education internet site, 3574.5 learners were registered nationally for ND in the Chemical Engineering Technology field, while 278.33 diplomas were issued, which translates into a graduation rate (throughput ratio) of 8%. This can be compared to a 100% pass rate, where the graduation rate is 33%. The SA YEARBOOK 2007/08 | EDUCATION contains the National Curriculum Statement (NCS) for schools, which is built on a number of principles including Outcomes Based Education (OBE). In 2008, school pupils are expected to write the National Senior Certificate examination. Although the National Plan for Higher Education (2001) does not mention OBE, academics in higher education institutions have been required to convert their study guides to OBE format and some (including the author) have received training in OBE to become assessors. A preliminary study was performed at UJ in 2006 to gauge whether OBE methods could be implemented for large groups of learners. A test had been written that most learners found challenging, leading to a high failure rate. A supplementary assessment strategy based on OBE Formative Assessment was conceptualised to allow learners to improve their marks. The main findings of the preliminary study were that a large number of learners could be accommodated in the Formative Assessments
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On-line assessment workshop
- Authors: Huberts, Robert
- Date: 2015-02-16
- Subjects: Blackboard , University of Johannesburg , On-line assessment
- Type: Presentation
- Identifier: uj:6146 , http://hdl.handle.net/10210/13360
- Description: Please refer to full text to view abstract
- Full Text:
- Authors: Huberts, Robert
- Date: 2015-02-16
- Subjects: Blackboard , University of Johannesburg , On-line assessment
- Type: Presentation
- Identifier: uj:6146 , http://hdl.handle.net/10210/13360
- Description: Please refer to full text to view abstract
- Full Text:
Modeling approach - Flowchart for an in-situ Acid Mine Drainage neutralization
- Basika, Batshiku, Huberts, Robert
- Authors: Basika, Batshiku , Huberts, Robert
- Date: 2013
- Subjects: Acid mine drainage , Flowchart , Modelling , Neutralization
- Language: English
- Type: Abstract: Mining disturbs geologic formations that took millions of years to form; once disruption has taken place, a variety of problems may arise, from physical hazards to pollution of water and soil. The main goal of this paper is to demonstrate the technical feasibility of ferric and ferrous ions in-situ removal from Acid Mine Drainage and to design suitable flowcharts that can be used to model in-situ neutralization. The principle is based on lime neutralization without agitation that consists of diffusion and neutralization of hydrogen ions within the solution, which will increase the pH and lead to diffusion and precipitation of ferric and ferrous ions. Experimental tests were conducted with raw Acid Mine Drainage solution from Randfontein Mine (Johannesburg, South Africa) and the method shows that it is possible to achieve about 90 - 98% efficiency for ferric and ferrous ions in-situ removal from Acid Mine Drainage. , Conference proceedings
- Identifier: http://hdl.handle.net/10210/16892 , uj:15819 , Basika, B. & Huberts, R. Modelling approach - flowchart for an in-situ Acid Mine Drainage neutralization. International Conference Proceedings of PSRC, Johannesburg, 15-16 April 2013.
- Full Text: false
- Authors: Basika, Batshiku , Huberts, Robert
- Date: 2013
- Subjects: Acid mine drainage , Flowchart , Modelling , Neutralization
- Language: English
- Type: Abstract: Mining disturbs geologic formations that took millions of years to form; once disruption has taken place, a variety of problems may arise, from physical hazards to pollution of water and soil. The main goal of this paper is to demonstrate the technical feasibility of ferric and ferrous ions in-situ removal from Acid Mine Drainage and to design suitable flowcharts that can be used to model in-situ neutralization. The principle is based on lime neutralization without agitation that consists of diffusion and neutralization of hydrogen ions within the solution, which will increase the pH and lead to diffusion and precipitation of ferric and ferrous ions. Experimental tests were conducted with raw Acid Mine Drainage solution from Randfontein Mine (Johannesburg, South Africa) and the method shows that it is possible to achieve about 90 - 98% efficiency for ferric and ferrous ions in-situ removal from Acid Mine Drainage. , Conference proceedings
- Identifier: http://hdl.handle.net/10210/16892 , uj:15819 , Basika, B. & Huberts, R. Modelling approach - flowchart for an in-situ Acid Mine Drainage neutralization. International Conference Proceedings of PSRC, Johannesburg, 15-16 April 2013.
- Full Text: false
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