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Loose biomass briquettes production process in Maphophe village of Limpopo province of South Africa

- Shuma, Reuben M., Madyira, Daniel M.

  • Authors: Shuma, Reuben M. , Madyira, Daniel M.
  • Date: 2017
  • Subjects: Biomass , Combustion , Production and energy content
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/249424 , uj:25953 , Citation: Shuma, R.M. & Madyira, D.M. 2017. Loose biomass briquettes production process in Maphophe village of Limpopo province of South Africa.
  • Description: Abstract: Deforestation has significantly affected availability of reliable low cost energy resources in low income rural households. As a result, off grid communities are becoming less and less reliant on round wood for energy. However, large amounts of agricultural and forestry residues that are produced annually are destroyed in perennial veld fires and some are deliberately destroyed to prepare for new crop fields. Accessing these loose agricultural and forest residues for energy use is one possible panacea. In the process, the challenges of deforestation can also be partly addressed. The main aim of this paper is to report on adopted methods to produce loose biomass briquettes using agricultural and forestry residues collected from the Maphophe village in Limpopo Province of South Africa. The goal was to avail workable processes for harnessing energy from loose biomass available in this locality. Production methods, energy content and combustion behaviour formed key performance variables. Two types of binders were tried, namely cow dung and cactus plant paste. A 30 tonne hydraulic press was using to compact the mixture of loose biomass and binder into briquettes. Out of 12 loose biomass samples collected, the best performing include ground nutshells, Mopani leaves, yellow thatching grass and sugarcane leaves. Performance was based on density, energy content and combustion behaviour. Cow dung was found to be the best binder and produced briquettes that offer a viable energy source for off grid communities.
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Effect of plunge depth on weld integrity of friction stir welds of dissimilar aluminium and copper

- Ewuola, Oluwatoyin O., Akinlabi, Esther Titilayo, Madyira, Daniel M.

Investigation of the parameters governing the performance of jet impingement quick food freezing and cooling systems – a review

- Marazani, Tawanda, Madyira, Daniel M., Akinlabi, Esther Titilayo

Repair of cracks in metals : a review

- Marazani, Tawanda, Madyira, Daniel M., Akinlabi, Esther Titilayo

Development of the loose biomass briquetting value chain

- Madyira, Daniel M.

  • Authors: Madyira, Daniel M.
  • Date: 2016
  • Subjects: Agricultural residue , Biomass , Loose biomass
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/217127 , uj:21601 , Citation: Madyira, D.M. 2016. Development of the loose biomass briquetting value chain.
  • Description: Abstract: Biomass (roundwood, agricultural residues, forestry residues, organic municipal waste) has the largest carbon reserve with potential to replace unsustainable fossil energy sources. Furthermore, off grid communities produce significant amounts of loose biomass through agricultural and forestry activities. These include maize stalks, tobacco stalks, ground nut leaves and stalks, tree leaves, elephant grass etc. These are traditionally burnt in fields after harvesting. In addition, annually, forestry residues such as elephant grass, yellow thatching grass, dry tree leaves etc. are destroyed in perennial veld fires. Such loose biomass can be harnessed for cooking and heating and thus minimise the use of round wood, which results in defor! estation that cause desertification if not done sustainably. The major challenge in harnessing energy from loose biomass is their low energy density. This can be overcome by developing loose biomass briquetting technologies. This paper reports on the development of loose biomass briquetting technologies at the University of Johannesburg over the past five years. These include shredding, pre-treatment, compaction, off grid solar drying, and combustion. Briquetting required the selection of good feed stock and binders. Cow dung and cactus leaves were found to be good binders producing briquettes with good combustion behaviour. The developed loose biomass briquettes were tested for moisture content, energy content and combustion behaviour and were found to be adequate for domestic cooking and heating requirements.
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Development of container based community factories

- Madyira, Daniel M.

  • Authors: Madyira, Daniel M.
  • Date: 2016
  • Subjects: Community factories , Container factories , Home lighting system
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/216957 , uj:21578 , Citation: Madyira, D.M. 2016. Development of container based community factories.
  • Description: Abstract: The main obstacle to electrification in Africa is not constructing power stations and building overhead power lines. It is working out how to help the region's households acquire sustainable energy with limited and irregular cash flows, little collateral and no access to credit. They cannot afford to pay for the huge investment needed to bring electricity to them. Even if the electricity was brought to them, most can barely afford to pay for usage. This problem can only be addressed by providing tools that bring wealth to the communities. After water, food and shelter comes the need of lighting to extend the productive hours of the day. The Department of Mechanical Engineering at the University of Johannesburg, in collaboration with ! Ecovest, a South African upcoming small scale enterprise, developed an innovative solar home lighting solution that can be manufactured off the grid in a community based container factory. Solar lighting is significant for many without electricity and the developed solution allows the Sun to pay to eradicate expensive unsustainable on-grid energy. The container based solution empowers the community to create jobs and generate wealth while producing affordable and durable products due to reduced distribution and marketing costs. In existing and emerging markets, the gross product cost includes the costs of distribution which is well developed in existing markets but poorly developed in the emerging African market. Additionally, existing markets innovate incrementally (features of products) whilst emerging markets innovate radically (sustainable technology). Moving users from hazardous and expensive open flame solutions like candles to solar home systems, provides a more sustainable st! andard of living for off grid living.
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Microstructural evolution and mechanical characterizations of AL-TiC matrix composites produced via friction stir

- Abegunde, Olayinka O., Akinlabi, Esther Titilayo, Madyira, Daniel M.

  • Authors: Abegunde, Olayinka O. , Akinlabi, Esther Titilayo , Madyira, Daniel M.
  • Date: 2017
  • Subjects: Friction stir welding , Metal matrix composite , Aluminium
  • Language: English
  • Type: Article
  • Identifier: http://hdl.handle.net/10210/236151 , uj:24161 , Citation: Abegunde, O.O., Akinlabi, E.T. & Madyira, D.M. 2017. Microstructural evolution and mechanical characterizations of AL-TiC matrix composites produced via friction stir.
  • Description: Abstract: In this research work, ample study was conducted on the material characterization of aluminium (Al) and titanium carbide (TiC) metal matrix composites produced via friction stir welding. Different process parameters were employed for the welding process. Rotational speeds of 1600 rpm to 2000 rpm at an interval of 200 rpm and traverse speeds of 100 to 300 mm/min at an interval of 100 mm/min were employed for the welding conducted on an Intelligent Stir Welding for Industry and Research (I-STIR) Process Development System (PDS) platform. The characterizations carried out include optical microscopy and the scanning electron microscopy analyses combined with Energy Dispersive Spectroscopy (SEM/EDS) techniques to investigate the particle distribution, microstructural evolution and the chemical analysis of the welded samples. Vickers microhardness tests were used to determine the hardness distribution of the welded zone and tensile testing was conducted to quantify the strength of the welded area to the base metal in order to establish the optimal process parameters. Based on the results obtained from the characterization analysis, it was found that the process parameters played a major role in the microstructural evolution. Homogenous distribution of the TiC particles was observed at high rotational speed of 2000 rpm and low traverse speed of 100 mm/min. The highest hardness value was measured at the stir zone of the weld due to the presence of the TiC reinforcement particles. The tensile strength also increased as the rotational speed increased and 92% joint efficiency was recorded in a sample produced at 2000 rpm and 100 mm/min. The EDS analysis revealed that Al, Ti and C made up the composition formed at the stir zone. The optimum process parameter setting was found to be at 2000 rpm and 100 mm/min and can be recommended.
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Energy content and combustion behaviour of loose biomass available in Limpopo

- Shuma, Rueben M., Madyira, Daniel M., Makonese, Tafadzwa, Oosthuizen, Gert A.

  • Authors: Shuma, Rueben M. , Madyira, Daniel M. , Makonese, Tafadzwa , Oosthuizen, Gert A.
  • Date: 2015-03-31
  • Subjects: Renewable energy , Solid biomass , Combustion
  • Type: Article
  • Identifier: uj:5150 , ISBN 9781479979127 , http://hdl.handle.net/10210/14220
  • Description: Solid biomass continues to be the primary energy source for a significant proportion of Sub-Saharan African society. It is estimated that 80% of energy for heating and cooking in this subcontinent is derived from round wood biomass resulting in estimated annual rate of deforestation of 0.7%. This is unsustainable. This is despite the existence of a substantial resource of loose biomass (forest and agricultural residues) that is produced and disposed of annually. However, one major challenge in harnessing loose biomass as a source of energy is low energy density and poor combustion behaviour. Biomass briquetting technologies can be deployed to improve energy density and combustion behaviour of loose biomass. This requires understanding of the energy content in locally available loose biomass sources. This paper investigates the calorific values (energy content) and combustion behaviour of loose biomass collected from a region in the Limpopo Province of South Africa. The aim of the investigation is to understand the energy value and hence viability of using such loose biomass with the overall goal of developing recipes for biomass briquetting in the region. Calorific values were measured for 12 samples of loose biomass and their combustion behaviour analysed. Certain loose biomass sources are then identified as potential briquetting candidates.
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Performance testing of a multi-layer biomass briquette stove

- Tom, Sivuyile, Shuma, Mikateko R., Madyira, Daniel M., Kaymakci, Abdullah

  • Authors: Tom, Sivuyile , Shuma, Mikateko R. , Madyira, Daniel M. , Kaymakci, Abdullah
  • Date: 2017
  • Subjects: Biomass , Briquette cook stove , Combustion
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/249441 , uj:25954 , Citation: Tom, S. et al. 2017. Performance testing of a multi-layer biomass briquette stove.
  • Description: Abstract: The production of greenhouse gases (GHG) has led to the Earth's surface temperature increasing by an average of 0.6°C in the 20th century. This is partly due to over reliance on fossil fuels. Human activities are estimated to account for about 69% of GHG emissions. There is now an urgent need for alternative fuels, especially renewables such as biomass, to mitigate this. In most of Sub-Saharan Africa, cooking is conducted in open fires using fire wood. This practice has poor health implications due to gases emitted largely due to incomplete combustion. The consequence is reduced mortality especially for women and children due to respiratory related diseases such as chronic obstruction pulmonary disease (COPD). The main aim of this work is to report on tests conducted on a low-cost biomass briquette domestic stove that was developed to improved biomass briquette combustion. Thermal efficiency, rate of heat loss and combustion effectiveness of the design was analysed as key performance variables of the stove. The goal was to develop a safe and reliable low-cost biomass briquette stove that will be used for domestic cooking in communities with low income streams. Stove geometry and temperatures at various points were identified as major contributors to stove effectiveness. During the investigation, controlled cooking test (CCT) method was used. Results showed good stove performance for typical cooking times.
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Investigating thermal performance of PCM plates for free cooling applications in South Africa

- Madyira, Daniel M., Mukhodobwane, Ranwedzi P., Jen, Tien C.

Energy content and combustion behaviour of loose biomass available in Limpopo

- Shuma, Reuben M., Madyira, Daniel M., Makonese, Tafadzwa N., Oosthuizen, Gert A.

  • Authors: Shuma, Reuben M. , Madyira, Daniel M. , Makonese, Tafadzwa N. , Oosthuizen, Gert A.
  • Date: 2016
  • Subjects: Renewable energy , Solid biomass , Loose biomass
  • Language: English
  • Type: Conference proceeding
  • Identifier: http://hdl.handle.net/10210/92337 , uj:20217 , Citation: Shuma, R.M. et al. 2016. Energy content and combustion behaviour of loose biomass available in Limpopo.
  • Description: Abstract: - Solid biomass continues to be the primary energy source for a significant proportion of Sub-Saharan African society. It is estimated that 80% of energy for heating and cooking in this subcontinent is derived from round wood biomass resulting in estimated annual rate of deforestation of 0.7%. This is unsustainable. This is despite the existence of a substantial resource of loose biomass (forest and agricultural residues) that is produced and disposed of annually. However, one major challenge in harnessing loose biomass as a source of energy is low energy density and poor combustion behaviour. Biomass briquetting technologies can be deployed to improve energy density and combustion behaviour of loose biomass . This requires understanding of the energy content in locally available loose biomass sources. This paper investigates the calorific values (energy content) and combustion behaviour of loose biomass collected from a region in the Limpopo Province of South Africa. The aim of the investigation is to understand the energy value and hence viability of using such loose biomass with the overall goal of developing recipes for biomass briquetting in the region . Calorific values were measured for 12 samples of loose biomass and their combustion behaviour analysed. Certain loose biomass sources are then identified as potential briquetting candidates .
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CFD evaluation of premixed and non-premixed models as suitable representatives of fixed-bed biomass combustor freeboard

- Lekwana, Mathope T.L., Madyira, Daniel M., Oosthuizen, Gert A., Makonese, Tafadzwa,N.

  • Authors: Lekwana, Mathope T.L. , Madyira, Daniel M. , Oosthuizen, Gert A. , Makonese, Tafadzwa,N.
  • Date: 2016
  • Language: English
  • Type: Conference proceeding
  • Identifier: http://hdl.handle.net/10210/92312 , uj:20214 , Citation: Lekwana, M.T.L. et al. 2016. CFD evaluation of premixed and non-premixed models as suitable representatives of fixed-bed biomass combustor freeboard.
  • Description: Abstract: This paper presents a comparison of the performance of two numerical (CFD) models with experimental data obtained for a fixed-bed biomass domestic cooking stove. The two numerical models are two different representations of the possible behavior of the gas region of the combustor under consideration. The one model considers the pyrolysis products emanating from the fuel bed to be premixed with the oxidant (air), while the other model supposes that the pyrolysis products combusting in the freeboard enter this region through a stream that is separate from that of the oxidant. The geometry of the combustion chamber of the stove from which the experimental data was obtained is cylindrical with l lcm diameter and 25 cm depth. The study particularly monitors the exit flame temperature of the cylindrical combustor through the use of k­ type thermocouples in the experimental case. The fuel used in the experiment is peanut shells. The premixed model achieved an exit temperature of 435K while the non-premixed model achieved an exit temperature of 747.9K. On the other hand, the highest experimentally obtained temperature is 778.lSK whereas the average experimentally obtained temperature is 641. lSK. Consequentl y the non-premixed model is chosen as the better representative of the freeboard.
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Emissions testing of loose biomass in Limpopo province of South Africa

- Shuma, Mikateko R., Madyira, Daniel M., Oosthuizen, Gert A.

Design of chilled ceiling displacement ventilation for direct expansion HVAC system

- Madyira, Daniel M., Kaymakci, Abdullah

  • Authors: Madyira, Daniel M. , Kaymakci, Abdullah
  • Date: 2016
  • Subjects: HVAC , Displacement ventilation , Chilled ceiling
  • Language: English
  • Type: Conference proceeding
  • Identifier: http://hdl.handle.net/10210/92201 , uj:20201 , Citation: Madyira, D.M. & Kaymakci, A. 2016. Design of chilled ceiling displacement ventilation for direct expansion HVAC system.
  • Description: Abstract: Displacement ventilation is a low cost ventilation technique used in distributing conditioned air in Heating, Ventilation and Air Conditioning (HVAC) systems. This is a ventilation strategy well suited to significantly reduce building energy consumption in this age of high energy costs, global warming and climate change. This is achieved through the leveraging of natural buoyancy driven flow in the conditioned space in a way that minimizes energy expenditure in supply and extraction fans. In addition, the conditioned air is supplied at higher temperature implying lower energy demand for cooling units. The global legislative move towards greener buildings demands the use of sustainable and energy efficient air conditioning systems of which displacement ventilation makes a major contribution. One of the challenges in using displacement ventilation is the stratified temperature distribution in the conditioned space. The temperature gradients between the ceiling and the floor can lead to decreased comfort conditions. One approach to overcome this problem is to use the chilled ceiling. How does one size the chilled ceiling system in such cases? The purpose of this paper is to present a detailed design analysis of a displacement ventilation chamber that includes chilled ceiling. The chamber utilizes an under floor air supply system into a conditioned space configured to represent typical office space. The construction and performance testing of the displacement ventilation testing chamber is then reported in a subsequent paper.
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Determining optimum parameters for manual compaction of loose biomass

- Madyira, Daniel M., Kaymakci, Abdullah

  • Authors: Madyira, Daniel M. , Kaymakci, Abdullah
  • Date: 2016
  • Subjects: Briquetting , Loose biomass , Optimum parameter introduction
  • Language: English
  • Type: Conference proceeding
  • Identifier: http://hdl.handle.net/10210/92227 , uj:20205 , Citation: Madyira, D.M. & Kaymakci, A. 2016. Determining optimum parameters for manual compaction of loose biomass.
  • Description: Abstract: Significant amounts of loose biomass are produced annually through agricultural and forestry activities. It is common practice to burn these loose biomass deliberately after harvesting or in accidental veld fires in the case of forestry. This energy could be harnessed for cooking and heating. The challenge with the use of loose biomass lies in its low density and hence low energy content which can be improved through densification. The aim of this paper is to determine the optimum densification parameters that can be used to develop manual briquetting technologies to empower poor communities to harness the energy available in loose biomass that they dispose annually. This forms part of a larger project aimed at developing off grid biomass value chain technologies. Using loose grass and loose leaves, experimental data revealed an optimum density of 1250 kg/m3 and a corresponding densification pressure of 40 MPa. In addition, a comparison of the thermal profile of solid round and round hollow briquettes showed more superior performance of the round hollow briquette based on recorded maximum combustion temperatures. Briquettes with a hole in the middle are therefore preferred to solid briquettes.
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Characterizing sunflower oil biodiesel blends as alternatives to fossil diesel

- Madyira, Daniel M., Nkomo, Zanele, Akinlabi, Esther Titilayo

  • Authors: Madyira, Daniel M. , Nkomo, Zanele , Akinlabi, Esther Titilayo
  • Date: 2012
  • Subjects: Fossil diesel , Sunflower oil , Biodiesel
  • Type: Article
  • Identifier: uj:4666 , ISBN 978-988-19252-2-0 , http://hdl.handle.net/10210/10046
  • Description: This paper reports on investigation into the feasibility of using sunflower oil based biodiesel blends as alternatives to fossil diesel fuel. The current global reliance on fossil fuels is coming to an end. This is driven on one hand by the dwindling global fossil fuel reserves and the understanding of the consequences of carbon accumulation in the atmosphere on the other. Dwindling reserves continue to drive global fuel prices upwards with negative effects on economic performance. Continued accumulation of carbon dioxide in the atmosphere is perceived to be responsible for the Greenhouse Gas (GHG) effect. This dual problem can be addressed by using alternative renewable fuel sources, which guarantee continued supply while maintaining global carbon neutrality. Biofuels are now largely recognized as viable options. Some of the challenges of using biodiesel in conventional diesel engines are their low density, which leads to low calorific value and acidity levels that threatens the structural integrity of the engine. Blending biodiesel with petroleum diesel can mitigate these effects and lead to better performing fuels. Fuel characterization is therefore essential to establishing notable similarities and differences between biodiesel and fossil diesel, and in determining optimum blending proportions for more effective use of biodiesels. In this investigation, biodiesel was produced from commercial sunflower cooking oil using the batch trans-esterification process with methanol in the presence of Sodium hydroxide catalyst. The characterization of the biodiesel was then conducted using Nuclear Magnetic Resonance (NMR), bomb calorimetry, acidity and flash point analysis, sulphur content tests and Gas Chromatography (GC). Blends ranging between 5% and 50% biodiesel concentration in Ultra-Low Sulphur Diesel (ULSD), in increments of 5% were analyzed. Results obtained confirmed that biodiesel has lower calorific value than ULSD, implying higher fuel consumption. The high flash point, almost at a temperature twice as high as that of ULSD, though advantageous for storage and transportation, results in poor ignition. The results also suggest that an increase in concentration of biodiesel leads to larger difference in properties between the blend and the ULSD. The pH value of biodiesel was found to be lower than that of ULSD which compromises engine structural integrity. Biodiesel’s chain length was found to contain an average of 19 carbons which makes it a viable option when compared to ULSD. Despite the relatively inferior properties measured, biodiesel still remains one of the most attractive fuel options.
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The effect of high speed machining on the fatigue performance of Ti6Al4V

- Madyira, Daniel M.

  • Authors: Madyira, Daniel M.
  • Date: 2016
  • Subjects: High-speed machining , Titanium alloys - Mechanical properties , Metal-cutting , Titanium alloys
  • Language: English
  • Type: Doctoral (Thesis)
  • Identifier: http://hdl.handle.net/10210/225157 , uj:22734
  • Description: Abstract: Grade 5 titanium alloy (Ti6Al4V) is the workhorse titanium alloy used in many industrial applications including aerospace, automotive, chemical and biomedical. Its attractive mechanical properties such as high strength-to-weight ratio, low density and corrosion resistance make it eminently suitable for such applications. However, its use is limited to these specialized applications due to its high cost. This high cost is mainly due to the primary processing of the material using the Kroll process. Little can be done, currently, to reduce the primary processing cost due to the high reactivity of titanium with oxygen. However, cost reduction measures can be implemented during secondary processing to make this alloy more affordable for general engineering applications. Such measures may include powder metallurgy, laser additive manufacturing, high performance machining and high speed machining. High speed machining (HSM) has been used to improve productivity and reduce component manufacturing costs in aerospace applications such as wing sections. HSM involves machining at high cutting speeds. Such high speed cutting can be implemented under milling or turning conditions. In this investigation, high speed cutting using turning was investigated. However, high speed machining has an effect on the surface and sub-surface condition of a machined component. This may affect the service performance of a component, especially fatigue life. Surface integrity descriptors that may be influenced by machining, and which may affect component fatigue life include surface roughness, micro hardness, microstructure and residual stresses. The cumulative effect of HSM on the fatigue behavior and life of components is largely unknown. This work aims to redress this by conducting experimental investigations supported by numerical analysis, on the effect of HSM on the fatigue performance of turned components for finish cutting conditions of Ti6Al4V. Literature study showed that residual stresses induced during HSM have a significant influence on fatigue performance. The effect of HSM on residual stresses was therefore investigated on specimens machined on 75 mm diameter forged bar of Ti6Al4V. The specimens were... , D.Ing. (Mechanical Engineering)
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Force feedback analysis: friction stir welding of aluminium metal matrix composite

- Abegunde, Olayinka O., Akinlabi, Esther Titilayo, Madyira, Daniel M.

Anaerobic digestion for sustainable energy : a brief review

- Kumba, Tresor K., Akinlabi, Esther Titilayo, Madyira, Daniel M.

Development of a validated numerical model of an unreinforced T-section pipe for large dams

- Naicker, Ashley, Madyira, Daniel M., Mashinini, Peter M.

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