Theses and dissertations (Engineering and Built Environment)

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Acousto-ultrasonics for defect assessment of composite materials
(2002) Dugmore, Kevin M.; Jonson, Jon David; Walker, Mark
The experiments and their results contained herein will form the basis for the development of a portable non-destructive testing device for composite structures. This device is to be capable of detecting any of a variety of defects and assessing their severity within a short time
Adoption of intelligent transport systems for sustainable transportation in secondary cities of South Africa : a case of Port Shepstone
(2019-08) Madihlaba, Goodness Lerato; Musvoto, Godfrey Gombana
Transportation is one of the major phenomenon which often directs population increase, investments and land use patterns in cities. Most cities, particularly secondary cities often do not entirely plan for future transportation when planning for massive investment developments thus leaving such cities with transportation challenges which include aging transport infrastructure, increased traffic patterns, insufficient parking spaces, high-accidents rates, to name a few. The most ignored transportation solution in secondary cities is the use of technology to manage transportation challenges in which such solutions may include the establishment of Intelligent Transport Systems (ITS). This research study seeks to examine what are the possibilities of using ITS to address the transportation challenges of the secondary city of Port Shepstone, what are the recommendations that can be put forward for establishment of ITS in Port Shepstone. In an attempt to discover these questions, the study conducts a literature review analysis which outlines what others have done in this research area and progressively attempts to provide recommendations on the possible establishment of ITS solutions in Port Shepstone. The literature review focuses on five (5) functional areas (i.e. Advanced Traveller Information Systems (ATIS); Advanced Transportation Management Systems (ATMS); Advanced Public Transport Systems (APTS); Enabled Transportation Pricing System (ETPS) and Data Acquisition Management Systems (DAMS)) which their possibility of being established in the secondary city of Port Shepstone is investigated The literature review analysis is supplemented by semi-structured interviews with various stakeholders within the transportation sector; and their views are constructively analysed to draw converging findings. The empirical findings from both literature review analysis and conducted interviews provide meaningful answers to the research questions and enabled the researcher to draw fundamental recommendations and possible ITS solutions to address the transportation challenges of Port Shepstone.
Aerobic sequencing batch reactor for the treatment of industrial wastewater from the brewery
(2017) Shabangu, Khaya Pearlman; Chetty, Maggie; Bakare, Babatunde F.
One of the major effects of socio-economic change due to industrialisation is the generation of industrial wastewater, which requires treatment before being released into the environment. Laboratory-scale aerobic sequencing batch reactors under suspended-growth heterotrophic activated sludge were operated in different aeration configurations to study their effect on the treatment of wastewater generated by a local brewery. The main purpose of this study was to evaluate the performance of the two laboratory-scale aerobic sequencing batch reactors treating brewery wastewater under continuous low-oxygen dosing concentration and cyclic aeration schemes on SBR operation. The characterisation of brewery wastewater was undertaken to assess the physicochemical composition of the wastewater produced from one of the breweries in South Africa (SAB). The data showed distinctive characteristics of brewery wastewater, which coincided with studies previously carried out on characterisation of brewery wastewater. The COD average concentration of the brewery influent was 7100 mg/L, with average pH values of 7. The BOD and the total solids content of the brewery wastewater influent from the facility were both high, implying that the influent was very rich in organic content and its discharge into water-receiving bodies or the municipal treatment plant could have adverse effects. From these results, a need for a competitive treatment technology was clearly highlighted so as to carry out a feasible treatment of the influent for the brewery industry. The aerobic sequencing batch reactors were designed, fabricated and set up for laboratory-scale treatment of wastewater from the brewery for 15 weeks. The performance of the two SBR configurations was determined with reference to COD, BOD, TS, VS and TSS. The experimental results demonstrated that wastewater generated from the breweries can be treated successfully using both aeration configurations. The results obtained indicated that treatment efficiencies in terms of COD and BOD were 94 % and 85 % respectively, for the reactor operated under continuous aeration configuration, while 81 % and 65 % was achieved for the reactor operated in the cyclic aeration scheme. The findings from this study demonstrate that the performance of the reactor operated under the continuous aeration scheme was successful, and showed statistically significant differences from the performance of the reactor operated under cyclic aeration schemes. These findings imply that there is a potential for the equipment, including financial benefit as a result of operating aerobic sequencing batch reactors for treating brewery wastewater under continuous low-oxygen concentration dosing schemes. In this study, it was also established that the maximum COD removal could be reached at an optimum hydraulic retention times of 5 days for both reactors. This was based upon viewing the experimental data; it appeared that the most significant difference in percentage COD removal was for HRTs 3 days and 4 days. Although, due to less percentage COD removal observed from HRTs 5 days till 7 days, it was hence established that the optimum removal of high strength organics in the brewery wastewater could be achieved within 5 days of treatment time. The pH adapted at an average of 7 for all batch experimentations of the study. The temperature maintained an average of 23 oC ambient, throughout the experimental period. These physical parameters ensured that the microbial population was kept healthy, without inhibiting its biological degradation activity. Although, sludge build up was observed in both aerobic SBRs on completion of each batch operation due to solids retention and organic pollutants biodegradation from the brewery wastewater. It was perceived that frequently reseeding both aerobic SBRs, as an alternative to 28 days sludge retention time would enhance the recovery of biomass, thus improving the overall removal of TSS consequently minimising sludge bulking in both reactors.
Alcohols conversion over transition metal based catalyts
(2018) Ndebele, Mthobisi Sbonelo; Isa, Yusuf Makarﬁ
Ethanol and butanol obtainable through fermentation of lignocellulose biomass have become promising alternative feedstock for production of fuels as they are biodegradable and sustainably regenerated via the photosynthesis cycle. The properties of hydrocarbons produced through alcohol conversion closely resemble those of gasoline. Catalytic systems are reported to play a vital role during alcohol conversion to hydrocarbons. In this study ethanol and butanol were used as a feedstock for production of hydrocarbons over Fe, Zn and Ni catalyst systems supported on zeolite ZSM-5 (Zeolite Socony Mobil-5) and activated carbon (AC). X- Ray Diffraction (XRD), Scanning Electron Microscope (SEM) coupled with Energy- dispersive X-ray spectroscopy (EDS) and Brunauer, Emmet, and Teller (BET) analyses were employed for catalyst characterization. XRD patterns confirmed the success of metal doping on ZSM-5 and activated carbon supports. Major peaks at 7.96° and 23.97° corresponding to ZSM-5 crystals were observed in ZSM-5, and AC was found to be amorphous. Impregnation with metals reduced the crystallinity of ZSM-5 supported catalysts. Whereas SEM analysis showed that catalysts supported on ZSM-5 exhibited irregular shapes and catalyst supported on activated carbon exhibited disordered structures. The BET analyses confirmed that the surface areas of promoted catalysts decreased after metal doping. Evaluation of the catalysts were carried out in a ½ inch stainless steel reactor at 400 °C and atmospheric pressure with a weight hourly space velocity (WHSV) of 2.5 h-1 (g feed)/ (g catalyst). The ZSM-5 support performed better than activated carbon support. More than 90% conversion was achieved over catalysts supported on ZSM-5. Production of hydrocarbons over catalysts supported on activated carbon were as a result of the active component. Conversion of feedstock was observed to produce more benzene, toluene and xylene (BTX) compounds with an increase in butanol content. 100% conversion was achieved with pure butanol and not more than 99.86% conversion was achieved with pure ethanol. Catalyst systems supported on HZSM-5 and activated carbon were successfully synthesised. Ethanol, butanol and ethanol-butanol mixtures were successfully converted to liquid hydrocarbons and the conversion was greater than 90%. On the promoted catalysts, production of BTX were suppressed and various metals were observed to perform differently.
Anaerobic co-digestion with industrial wastewater for biomethane production
(2020-10-20) Adedeji, Jeremiah; Chetty, Maggie
The increasing demand for energy has led to the utilization of fossil fuels more abundantly as a quick alternative for generation of energy. The use of these sources of energy however as led to the generation of greenhouse gases which tend to cause climate change, thus affecting the ecosystem at large. Thus, there have been the search for alternative sources which cannot be depleted but do generate minimal greenhouse gases. One of such alternate sources is industrial wastewater which have shown to have high concentration of nutrients in the form of organic contents which can be converted by micro-organisms into energy, usually known as biogas, comprising majorly of CH4, CO2 and H2. Another important factor is that industrial wastewaters are a renewable energy source which are continuously generated due to increasing urbanisation and population growth. In this study, the characteristics of three agro-industrial based wastewaters used shows their potential for application in anaerobic co-digestion”. Anaerobic co-digestion method was utilized to harness the synergetic effect of both sewage sludge and agro-industrial wastewater as co-substrate for the generation of biomethane. The result of the effect of varying mix-ratio of the substrates on biomethane production of sugar wastewater and dairy wastewater indicated that mix-ratio of 1:1 for sewage sludge to sugar wastewater operated at 35oC was suitable for optimum generation of biomethane of 1400.99 mL CH4/g COD added and COD reduction of 54%. The model generated using design expert was found to navigate the design space and could perfectly predict the yield of biomethane effectively for the sugar wastewater mix. The biomethane potential tests (BMP) experiment using varying inoculum-substrate ratio (ISR) showed that operating at mesophilic temperature of 25oC with ISR of 1:2 and 2:1 for sugar wastewater and dairy wastewater respectively does increase the methane production within the first three (3) weeks. The kinetic models that best fit the anaerobic co-digestion for sugar wastewater was the first order model while the simplified Gompertz model favoured the dairy wastewater perfectly. The biomethane potential tests indicate significant increase the biomethane production and as well reduction in the volatile solid and chemical oxygen demand (COD) content. In conclusion, both sugar and dairy wastewater can be recommended as co-substrates for anaerobic digestion of sewage sludge for increased and improved biomethane production while simultaneously reducing their COD content at the same time.
Analysing South Africa’s automotive energy consumption : application of index decomposition analysis
(2021-01) Machivha, Rofhiwa Tevin; Olanrewaju, Oludolapo Akanni
This research focuses on applying the Index Decomposition Analysis (IDA) to South Africa’s automotive industry to decompose energy consumption and further make use of regression analysis to understand how it relates to the economy. South Africa has been going through an energy crisis, which has resulted in ongoing load shedding as a way to manage this crisis. Looking at South Africa’s energy generation, it can be noted that the entire country depends on Eskom as the main supplier and of electricity, but it is unable to keep pace with the demand. The results of the research show that there exists a nexus across all segments between energy consumption and GDP; furthermore, the decomposition results show that energy consumption in some years experienced a reduction. However, it can be seen that an increase in energy consumption year on year is predominant; this then suggests that the reductions experienced were the result of a special event; hence, it can be deduced that overall energy consumption has increased slightly. The increase is as a result of the activity effect which contributed the most towards this whilst the structural effect yielded a negligible contribution. Lastly, the intensity effect contributed to the reduction in energy consumption as a result of sectoral shifts; this reduction contributed towards keeping the overall increase in energy consumption low. This study aimed to outline the differences in energy consumed during the production of different vehicle classes, citing various factors responsible for the changes in energy consumption during vehicle production, raising awareness with manufacturers on the impact industrial energy consumption has on the national energy grid and on advising medium to large manufacturers to become suppliers.
Analysis of student success in Mechanical Engineering at the Durban University of Technology
(2016) Graham, Bruce Robert; Walker, Mark
The department of Mechanical Engineering at the Durban University of Technology currently offers a National Diploma (ND) and a Bachelor’s Degree in Technology (BTech), as well as a MEng. and a DEng. This thesis details four areas of study that were undertaken in an attempt to identify potential impediments to student success in the department, using readily available data. The universities’ management information system (ITS) was the primary source of data, but limited data was also obtained from courses that the author taught, as outlined in section (4) below. A grounded action research framework was selected as the methodological framework for these studies as it allowed the freedom to refine an investigation as it progressed as well as to implement potential solutions and determine their efficacy. The four areas covered were: (1) Analysis of trends in student success rates. A number of changes were made to the National Diploma over a five year period including the introduction of supplementary examinations, the removal of elective offerings, the change in the sequence of subjects offered and a reduction in contact time. This same period also coincided with the first cohort of students entering with the new NSC matric qualification. This study examined the success rates within subjects, across four semesters of study, from 2007 until 2010 and attempts to show the effects, either positive or negative, that these changes have had. The success rates of subjects within the BTech programme were also interrogated for this same period. These results were also categorised according to whether students obtained their diploma at DUT or at another institution allowing a comparison between the two cohorts. (2) Workplace Learning (WPL). Anecdotal evidence suggested that the manner in which the WPL components were offered had a negative effect on student throughput as well as not providing substantial opportunity for the integration of experience gained in industry with the academic programme. This study, utilising WPL registrations from 2007 to 2010, examined the average time taken to complete the WPL components, the percentage of the academic component completed before and during the WPL period as well as the dropout rate. (3) Relationship between NSC results and success in Mechanical Engineering. The purpose of this study was to determine if relationships could be found between student’s NSC results and success within the programme. This would inform if the departmental entrance requirements were of an appropriate level to ensure prospective students a reasonable chance of success. Results of selected NSC subjects were correlated with those of selected diploma subjects. The distributions of success in these subjects were tabulated against the NSC results allowing a better understanding of the relationship between them. (4) Investigation into causes of poor performance in Hydraulic Machines III. This study was undertaken to better understand the competencies and learning practices of the students in the author’s class. This involved the interrogation of the performance of students over a number of assessments, the tracking of usage of online resources and the tracking of lecture attendance, and subsequent correlation with performance. These studies have led to a better understanding of the programmes offered and have put the department in a position to make informed decisions regarding interventions aimed at increasing student success. The work covered in this thesis was presented in two full papers (Graham and Walker, 2011, Graham and Walker, 2015) and two extended abstracts (Graham and Walker, 2013, Walker and Graham, 2013).
An analysis of the factors influencing the relationship between soil properties and optimum moisture content and the formulation of an abbreviated test method of determinig maximum dry density
(1997) Allinsin, Anthony James; Coetzee, J.
The strength and durability of any soil structure is dependent on the quality of the compaction of the soil. This quality is measured by employing a standard compaction test, which provides a standard with which density may be compared, called the maximum dry density, and the moisture content of the soil at which this is achieved, called the optimum moisture content. As a matter of routine during quality control, the particle size distribution, plasticity index and liquid limit of the soil are determined at the same time as its maximum dry density and optimum moisture content.
Analysis of the viability of additive manufacturing for rapid tooling: A case study for the plastic industry
(2022-05-13) Pancha, Uttam Bhana; Olanrewaju, Oludolapo Akanni
The current environment of changing market trends that include mass customization, sustainability, environmental impact and localized production drives the manufacturing industry to strive for additive manufacturing because of the versatility of the technology. Injection Moulding Company (IMC) is using traditional manufacturing approaches which compromise its competitiveness resulting in decreased production rate and high operational costs due to lengthy changeover times. The aim of the study was to investigate the viability of additive manufacturing technology for the manufacture of moulds to reduce operational costs. ABC mould demand classification analysis conducted for the top 16 moulds revealed that the moulds for the switch cover ranked highest in terms of the demand of moulds that were fabricated by IMC. The value stream map revealed that there was room for improvement in terms of push to pull and frequent lot transfer, standardising work, reducing cutting time and process scrap, as well as introducing poka yokes and cellular manufacturing, and it was proposed to reduce material movements and setup times. Through the deployment of group technology and rank clustering algorithm, three mould families and three machine cells were derived. As a result, the mould fabrication process was improved by reducing material movements and reducing setup times. Analytic hierarchical process was deployed as criteria for comparison and selection of the best 3D printing technology from among the recent additive manufacturing (AM) technologies that would meet surface finish, dimensional accuracy, cost, and manufacturing lead time requirements. Four AM options included Multilevel Concurrent Printing, MELD technology, Metal Jet 3D printer, and VELO3D. The final results indicated that the VELO3D is better than other additive manufacturing technologies for rapid tooling for the manufacture of moulds. The switch cover mould was then assessed for viability of fabrication through AM. The research proposed a process for evaluation of investment in VELO3D machine. A final decision was made through the comparison of AM technology, VELO3D versus traditional manufacturing capabilities in tool production. The traditional manufacturing was found to be characterised by a huge mould cost which was absent when additive manufacturing technology is adopted. The results demonstrated that VELO3D outperformed the traditional approach from a cost perspective leading to an 80% overall cost savings from the adoption of AM.
The analytical and experimental study on the establishment of a tidal power plant in South Africa
(2021-02) Mtukushe, Namhla Faith; Ojo, Evans Eshiemogie
The majority of South Africa’s electricity is generated from fossil-fuel plants that use mainly coal. In these power plants, the combustion of these fossil fuels liberates greenhouse gasses into the atmosphere that contribute to climate change. This problem coupled with the rapid depletion of fossil fuels has necessitated the need to explore the alternative form of energy such as renewable energy. Tidal energy is a form of ocean energy that can be considered as an alternative energy resource or renewable energy source. This form of energy has not been explored in South Africa, the only country in the world that is bounded by two oceans; the Indian and the Atlantic. Tidal energy can be harnessed from the movements of tides to generate electrical power. This study considered the possibility of harnessing tidal energy as the alternative energy source for power generation which can be used to mitigate the challenges associated with the energy crisis currently being experienced in the country. For this study, an extensive literature review was carried out to understand the tidal phenomenon, the concept of energy conversion from tides, the different techniques or technologies that can be used to generated power from tides. There are two main technologies used for converting tidal energy to electrical energy and these are the tidal barrage and the tidal streams. Based on the inferences drawn from the literature reviews concerning the tides experienced around the South Africa coastal region, it was identified that the tidal stream technique is applicable. Harmonic analysis of the tidal resource for four identified sites was conducted, from these analyses, Esikhawini was selected as an optimum site. Tidal streams extract the kinetic energy of tides and the mode of operation of tidal stream plants is determined by the type of tidal turbine employed. Several turbine designs were reviewed, a helical cross-flow turbine was selected due to its self-starting capability and its ability to operate in reverse stream flows. For this helical turbine, an analytical model using the blade element momentum theory (BEMT) was developed and was implemented on MATLAB environment. For the experimentation, a prototype was developed and tested in a laboratory concrete flume in the department of Civil Engineering at the University of KwaZulu-Natal. Based on the experimental results, an analysis of the unit turbine was done which was used to propose a conceptualized tidal power plant. Hence, the proposed tidal power plant was used to justify the reason for embarking on this study which is to ascertain the possibility of establishing a tidal power plant in South Africa.
Application of DMAIC to improve energy consumption in a commercial building
(2021-03) Kanyinda, Kabuya; Lazarus, Ian Joseph
Improving energy use in a commercial building has become the subject of great importance in organizations worldwide. Improving energy usage refers to the efforts to reduce energy consumption. Reducing energy consumption in commercial buildings can be accomplished through continuous supervision using appropriate managerial techniques. Commercial companies are required to use energy more efficiently and participate in energy improvement. This study seeks to improve electrical energy consumption in commercial buildings by Analysing the electrical data consumption and identifying the factors that contribute to high consumption using Six Sigma DMAIC (Define-Measure- Analyse-Improve-Control) problem solving methodology. A case study was used to validate the DMAIC framework. Two years of electrical consumption data of a case study done from January 2018 to December 2019 was collected and analysed. The study revealed an average increment in energy consumption of 3.9 %. The outcomes using statistical Pareto chart showed that the boiler is the highest significant energy user in the building with 38.3% due; followed by the kitchen with 24.2 %, followed by DB A and lifts with 20,1 % and the rest with 17.37 %. After the campaign of DMAIC, there was a reduction of 6 % in boiler consumption which was 2.3 % reduction of total consumption of the month for the building. Therefore, the study successfully demonstrates how Six Sigma DMAIC methodology can be applied to improve electrical consumption in a commercial building and reduce its related costs.
The application of lean principles to mitigate greenhouse gas emissions in an automotive industry
(2020-09) Ramsunder, Keshav; Olanrewaju, Oludolapo Akanni
A common factor for industrial production is energy, and the level of energy consumed is typically used to measure the growth and economic development of countries. However, as the industrial sector expands and makes efforts to gain competitive advantage, there is a growing concern regarding energy consumption and the ecological burden related to energy use. Thus far, industry has relied on the Lean manufacturing paradigm to gain the contemporary benefits of profitability, flexibility, and increased efficiency. More recently, the association of Lean manufacturing and environmental impacts has grown in both the industrial and academic fields. The main aim of this research is to investigate the correlation between lean tools and their effect on Green House Gas emissions, ultimately measuring environmental performance. The research is quantitatively based and entails the study of a weld process production line at Toyota South Africa Motors. The environmental impacts of the production process were observed and measured before and after the implementation of three lean tools: Value Stream Mapping (VSM), Total Productive Maintenance (TPM) and Standardized Work. Comparing the outcomes, the study found significant differences in the pre-test and post-test of each lean technique applied. VSM allows one to visualize and magnify the environmental performance of the process, which allows for simple quantifying of environmental metrics. TPM brings to light that equipment that is regularly maintained to operate at optimum condition reduces non-value adding energy usage. However, in contrast, Standardized Work has shown minimal benefits within the context of this research. The findings of this research are beneficial as they contribute to gaining a better understanding of the way lean tools affect environmental performance. While the study contributes to the current body of knowledge, it can also enlighten Small to Medium Enterprises, practitioners and larger organizations to rethink current strategy and allow for simultaneous implementation of Lean Green operations.
An application of lean six sigma techniques to accelerate the implementation of Kaizen in the film packaging industry
(2021-01) Moso, Matshidiso; Olanrewaju, Oludolapo Akanni; Dewa, Mendon
The integration of lean six sigma techniques in manufacturing results in substantial improvement and hence a more profitable organization. The case study company is based in South Africa and specialises in manufacturing plastic film, which uses thin micron plastic for food packaging. The main goal of this research was to accelerate the rate of kaizen implementation by utilizing lean six sigma techniques in order to construct a semi-automated model. Lean six sigma is comprised of various problem-solving techniques. In this case study, 5Whys was combined with Ishikawa to construct a semi- automated model for an effective defect trouble shooting closure system. Defect trouble shooting system is also called a “non-conformance closure system”. It was evaluated that the procedure of non-conformance closure at the company was inadequate; this was identified as a major finding during an external ISO audit. An opportunity to utilize lean techniques was identified and implemented in order to satisfy the objectives of this research. The first objective was to define the requirements of ISO standards in order to find a suitable system that could be used. Defining the requirements was key for the researcher to get an idea of how the model should be constructed to suit ISO standard requirements. The second objective was to evaluate the current method and find the root cause of the problem; this objective highlighted all the possible causes that had resulted in an inadequate procedure for non-conformance closure. The third objective was to construct a model by integrating lean techniques that matched ISO standards. This objective was implemented in order to satisfy the research goals; a semi-automated model resulted in a catalyst for continual improvement. The fourth objective was to implement the semi-automated model on each non-conformance that was raised and the fifth objective was to reflect by monitoring and recording the results from the semi-automated model. This method resulted in a smooth flow system of non- conformance closure; the major finding closure was accepted after the auditors monitored the new semi-automated method. Automated non-conformance software, which integrates any system that needs corrective action, was recommended, and seven types of waste were recommended for further analysis. This semi-automated model can be used as a future programme parameter for completing an automated system to resolve non-conformances.
Application of optimal control for power systems considering renewable energy technologies
(2021-03) Chetty, Dhanpal; Sharma, Gulshan; Davidson, Innocent Ewaen
Over the last decade, power generation from renewable energy sources such as wind, hydro and solar energies have substantially increased globally and in South Africa. Of all the renewable energy sources, wind energy appears to be the most promising, considering design and costs. However, due to the intermittent nature of wind, the increased integration of wind energy into existing power systems raises several control challenges related to load frequency control (LFC) and tie-line power system stability. The stability of modern power systems, incorporating wind energy generations, will be significantly enhanced with the development of LFC strategies based on modern control theory, which is the focus of this research. This thesis presents the design, modelling and analysis, of two LFC control strategies for interconnected power systems, having wind power integrations. The first design is an optimal control strategy, based on error minimization through full state vector feedback, for a two-area interconnected power system consisting of hydro-thermal generations. The second design is a model predictive control (MPC) strategy, based output vector feedback of system state parameters, for a two-area interconnected power system consisting of thermal generations in each area. Both designs include the active power support from doubly fed induction generator based wind turbines (DFIG) in conjunction with the combined effort of a thyristor control phase shifter (TCPS) and super conducting magnetic energy storage unit (SMES). Both control strategies were simulated in MATLAB Simulink and positive results were obtained. The results show that the optimal control strategy is enhanced with power integrations using DFIG based wind turbines combined with the TCPS-SMES units and the MPC strategy is very robust and provides better dynamic performances even with parameter variations and generation rate restrictions.
Application of synthesized magnetic nanoparticles for biogas production using anaerobic digestion
(2023) Amo-Duodu, Gloria; Rathilal, Sudesh; Chollom, Martha Noro
South Africa is encountering severe challenges in the areas of energy, water, and wastewater management in recent times. This study addresses both water and energy aspects. It aims at using synthesised magnetic nanoparticles (MNPs) on anaerobic digestion (AD) for biogas production from various wastewater sources in South Africa. The study experimented the feasibility of five different synthesized magnetic nanoparticles, magnetite (Fe3O4), copper ferrite (CuFe2O4), nickel ferrite (NiFe2O4), magnesium ferrite (MgFe2O4) and aluminium ferrite (AlFe2O4) on two different wastewater samples (industrial and municipal wastewater) from three sampling sources, Umbilo water works, Umgeni water and a sugar refinery industry. Five research objectives were accessed. The first objective was the synthesis and characterisation of MNPs using scanning electron microscopy/energy dispersive x-ray (SEM/EDX), Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analysis. The results showed a surface morphology of facecentred and monoclinic crystal structures with a size less than 20 nm. The nanostructures of ferrimagnetite and magnetite were obtained, and it had an O-H stretching and Fe-O vibration functional groups. The surface area obtained was found to be high for magnetite (Fe3O4) which was 27.597 m2 /g. The second objective was to evaluate the AD performance in terms of water quality and biogas production. This was carried out in two stages. The first was to evaluate the five MNPs with sugar refining wastewater. The second stage was to evaluate the performance of three best performing MNPs on two wastewater samples from Umbilo wastewater. The results for the first stage showed good degradation of organic matter for the bioreactors with MNPs which resulted in a higher yield of biogas and methane as compared to the control as well as good removal of contaminant (chemical oxygen demand (COD), colour and turbidity). Among the five MNPs used, Fe3O4, NiFe2O4 and CuFe2O4 had a contaminant removal efficiency of 60- 70% and a cumulative biogas yield of more than 140 ml/day with more than 85% methane composition, hence these three MNPs were found to be the best performed MNPs. The results obtained from the second stage for the three best performed MNPs indicated a high pollutant removal efficiency of more than 70% for Fe3O4, as well as a biogas yield of more than 1100 ml/day and a methane composition of approximately 98%. The third objective was the evaluation and optimisation of the anaerobic magnetised system for biogas production while the fourth objective involved a comparative study between the performances of magnetised biochemical methane potential (BMP) to non-magnetised biochemical methane potential. From the optimisation study, the predicted results obtained from the BBD-RSM showed an average contaminant removal of 70% and a biogas yield of 522 ml/day at an optimum MNP load of 0.5 g, retention time of 45 days, inoculum load of 500 ml, and a temperature of 35℃ with a desirability of 96% as the optimum conditions. With less than 2% deviation, the confirmatory test demonstrated equal performance at the optimum conditions. Findings from the fourth objective indicated that the BMP system with MF exposure exhibited a contaminant removal rate of over 80% and a biogas generation of 1715 ml/day with a 99.94% methane composition. Overall, the system that included both MF and MNP performed better than the other in terms of biogas yield and colour removal. The final objective was the kinetic study of the anaerobic magnetised system using modified Gompertz and first-order kinetic models. The results obtained from the kinetics showed that the modified Gompertz model described the kinetics and dynamics of the anaerobic magnetised system better than the firstorder kinetic model with a correlation co-efficient (R2 ) over 0.9999 and an error less than 0.0002. Therefore, the possibility of using MNPs, particularly magnetite (Fe3O4), in an AD system for biogas production from wastewater was found to be extremely feasible and without negative environmental consequences. Incorporating both MF and MNP in AD was also beneficial for wastewater treatment because it eliminated the need for post-treatment.
Appraisal and optimization of energy-efficient green buildings in South Africa
(2024-05) Agbajor, Favour David; Mewomo, Modupe Cecilia
Generally, over 35% of global energy use and 40% of carbon emissions are attributed to the built environment while future forecasts indicate that these values may rise much further. In South Africa (SA), building stocks account for 40% of the country’s final energy demand which strains the country's coal-dependent energy grid and oftentimes results in power outages. Optimizing energy efficiency and thermal comfort while attaining the lofty goal of carbon neutrality is essential for all concerned stakeholders in the building sector globally. Meanwhile, green building (GB), being a recognized revolutionary theory and practice in the building industry, is suggested as a solution to SA’s environmental challenges. On this wise, this research aimed to develop energy-efficient models for optimizing green buildings into the design and operation of buildings to allay their environmental impacts. The goal was to enhance energy efficiency, decrease energy consumption, and mitigate carbon emissions across diverse climates, thus benefiting South Africa's built environment. To achieve the study's goals, three primary research objectives were identified and pursued namely: (i) To provide an overview on status-quo of green building development in South Africa with a view to explore the status quo and provide roadmap for improvement; (ii)To examine the energy-saving potential of incorporating building-integrated greenery systems towards climate-resilience in the subtropical climate zone of South Africa; and (iii) To investigate the energy-performance of green building renewable energy utilization systems within South Africa’s hot and arid climate zones. Initially, the study's first objective entailed a comprehensive literature overview integrating climate, sustainability, and building energy modeling within the South African context. This was carried out through a scoping review approach via the PRISMA guideline of reporting Subsequent objectives involved selecting reference buildings and creating hypothesized models as case studies based on six climate zones from the South African National Standard. For the second objective, a thorough and integrative approach that linked building energy modelling and varying climatic change was devised. The numerical parametric simulation and analysis, being a quantitative research approach was adopted as a data collection method. Similarly, the third objective employed numerical parametric simulation as a data gathering method in this research, which is based on a quantitative analysis to explore various design options iteratively. In the second and third objectives, Global climate databases, Meteonorm, Climate Consultant, and energy simulation software such as DesignBuilder, EnergyPlus, and Polysun were used for weather data analysis, climate modeling, and building energy simulation. The findings highlighted that while South Africa boasts notable green construction projects, scientific research progress has not matched international levels. The focus was on promoting green building adoption through standards, certifications, and incentives. However, gaps were observed in optimized energy performance and post-occupancy evaluation of existing buildings. Despite high awareness, the utilization of green building technologies among South African professionals did not meet anticipated levels. For the second objective, the study's findings indicated an increase in extreme heat waves with higher peak temperatures in the future. Building energy use in the study area is projected to rise by 8-24% from 2030 to 2080. Notably, heat gains primarily result from envelope thermal transfer rather than solar radiation. Greenery systems were found to effectively support green building goals and urban sustainability across anticipated seasons. Nature-based solutions proved successful in adapting to climate change compared to non-retrofitted conventional buildings. For the last objective, the study revealed regions with substantial solar irradiance, indicating potential for renewable energy adoption. It emphasized the need for durable BIPV systems in hightemperature conditions. BIPV modules generated more energy in Upington than Nelspruit due to varying solar radiation. Opportunities were identified for BIPV systems to achieve optimal power generation. The study provides a foundation for informed decision-making, policy formulation, and targeted research in sustainable building practices. The study presents practical principles to guide urban planners and policymakers in integrating eco-friendly technology into both new and existing building designs. This promotes sustainable urban development and reduces cities' carbon emissions. Going forward, to showcase the effectiveness of these energy-efficient and climate-responsive systems to the public and industry stakeholders, it is recommended to establish and enhance largescale demonstration projects in South Africa's subtropical, hot and arid regions.
An appraisal of building information modelling technology in building construction and maintenance in Africa : a case of Nigeria and South Africa
(2023-05) Toyin, James Olaonipekun; Mewomo, Modupe Cecilia
Building Information Modelling technology (BIM-T) continues to gain attention. Its adoption creates a platform that allows the built environment professionals to share project information through a common database. At the same time, there is an increased perception that implementing BIM on construction projects will positively influence building production throughout its lifecycle. Recent studies have revealed a low level of BIM implementation in the African construction industry. Currently, the utilisation of BIM for building production has received a significant acceptance rate in developed regions, while in African countries, it is still at an infant stage. Moreover, previous studies have established that BIM application comes with various barriers. These barriers contribute to its low adoption, application and implementation. Nevertheless, there are still some notable benefits and impacts on building production, which have been the main drivers for its continual adoption. Therefore, this study aimed to research BIM-T applications in African countries, focusing on the Nigerian and South African construction industries. The goals are to assess its level of awareness, usage, barriers hindering its application/implementation and benefits accruable with its adoption. BIM impacts the building production lifecycle and determines the strategies to promote its application among construction professionals for sustainable construction in developing countries. To achieve the objective of this research, an extensive review of the literature was conducted on usage, barriers to BIM adoption, application/implementation, benefits of adopting BIM, its impacts on building production, and strategies to promote its application/implementation. A structured questionnaire elicited constructive data from the Nigerian built environment professionals (NIA, NIOB, NIQS, and NSE) and the South African construction-related professionals (SACPCMP). The web-based (Google form) questionnaire was distributed online. According to the distribution among the professionals, 276 and 105 respondents indicated their willingness and availability to participate in the research from Nigeria and South Africa, respectively. The generated data was analysed using the following descriptive measures: mean item score (M.I.S), relative important index (RII), ranking and frequency and quantitative inferential analysis (factor analysis, pairwise comparison, one-way ANOVA and Kruskal-Wallis). It was found that there is a significant increase in the level of BIM awareness among Nigerian and South African construction professionals compared to previous findings. 98.55% and 96.19% of respondents, respectively affirmed that they are aware of BIM. Nevertheless, these findings established that there are still BIM-related barriers peculiar to both countries; the top common three barriers are low computer skills among some of the professionals, habitual resistance to change from the traditional style of design and build, and government's unwillingness to support BIM use. These barriers could be responsible for the professional’s low level of BIM tool usage. The study also revealed that all 13 identified BIM benefits are significantly important in both countries. From this, it could be concluded that BIM application has significantly improved the production of buildings through its contribution to performing tasks from building design to post-construction stages. Finally, the respondents identified the need for foundational knowledge in an educational institution on BIM tool use and its applications as a critical area of focus that could assist the promotion of BIM. This study has extensively documented the various research contributions carried out in this study's area of focus. The preliminary survey result concludes that the findings will assist the professional body in making intelligent decisions and adequate measures to advance the adoption, application/implementation of BIM among their members. It will also inform the institutions about what is required from their construction graduates to improve their employability in the industry.
Appraisal of career development among female professionals in the South African construction industry
(2022-05-13) Zungu, Hlumelo T.; Aiyetan, Olatunji Ayodeji; Mewomo, M. C.
Every human being aspires to attain to the top of his or her career. Failure results in dissatisfaction, poor productivity, and lack of interest and proper engagement in the career. The study aims to appraise career development (CD) among female professionals in the construction industry in South Africa. The study was conducted among registered female professionals in the SA construction industry. The purposive sampling technique was employed in reaching the sample. The sample frame comprised of registered female professionals within the South African Council for Project and Construction Management Profession (SACPCMP). The total number of registered professionals is 158 and the whole population was taken as the sample size. The questionnaire to the study was administered to the respondents online using Google forms survey. A total of 67 questionnaires were returned filled, representing 42.4% achieved rate.The inferential statistics was used for data analysis. The findings indicated that gender discrimination has a significantinfluence on females’ participation in CD in the construction industry. Training and continuing education in the construction industry’s influences contribution to CD for female professionals, family, and social commitments are impediments to career development for female professionals. Passion mostly motivates the interest in the career choice of females in the construction industry and the factor that most enhances the successof female professionals in career development is education. Recommendations include that policies put in place should be such that women are represented at all levels and the opportunities are granted fairly to ensure that females are not discriminated against. Provision for training programs be made and salaries for femaleprofessionals should be adjusted such that there is an allowance to cater for domestic assistance. Females should pursue or obtain higher degrees to be successful in career development in the construction industry. These qualifications are such that females couldbe placed in managerial positions. Therefore, the following post-graduate programs are recommended: Construction Management, Human Resource Management, Industrial Psychology, and many others
An appraisal of procurement challenges facing emerging contractors in public sector projects in South Africa
(2024-05) Bangani, Sibabalo Edmond; Mewomo, Modupe Cecilia
Poor participation and performance of emerging contractors in public sector construction projects is currently an issue of major concern in South Africa (SA), as economic development relies mainly on the sustainability of small businesses. While the South African government has endeavoured to make provisions for the advancement of the emerging contractors through the regulatory framework and Section 217(i) of the constitution, earlier studies have revealed that the emerging contractors continue to face several procurement challenges. These procurement challenges have adversely impacted the growth and development of small contractors. Unfortunately, the available provisions in the constitution and the regulatory framework have not been able to adequately solve the problem. This has led to a high rate of small business failures in South Africa. These procurement challenges include late payments, poor contract management, poor cash flow management, the complexity of regulations, too much competition, political interference, and a lack of skills in pricing techniques, to mention a few. This study aimed to appraise the procurement challenges facing emerging contractors in public sector projects in South Africa with a view to developing strategies to mitigate the challenges experienced. The study focused on CIDB-registered construction companies in Gauteng province under CIDB levels 4 and 5 registered as general building and civil engineering classified contractors. The study adhered to a quantitative explanatory approach. A survey questionnaire comprising structured questions relating to the study’s objectives was drawn up and distributed to the participants. The data is presented using the tables while the analysis of the data was achieved through using the appropriate descriptive and inferential statistics to measure characteristics of the study population and to make inferences about the population from data set respectively. The study found that late payments, political interference, poorly managed cash flows, too much competition, and a lack of understanding of pricing techniques were the top five critical challenges facing the emerging contractors in the South African construction industry. Further investigation on the impacts of the identified challenges facing the emerging contractors in South Africa revealed that project cost and time overruns, lack of access to public sector contractors, loss of profits, blacklisting by creditors, liquidation, and abandoned projects negatively impact the success of the emerging contractors in South Africa. The study further identified potential measures to overcome the identified procurement challenges. These measures include: reviewing procurement policies for contractor development with emphasis on business and management skills development programmes; access to finance be made easily accessible; contractors be trained to separate business operations from family operations, including proper cash flow management; skills development training specifically for small contractors; joint venture partnerships for emerging contractors to curb financial and administrative burdens and skills transfer; implementing early payment arrangements with the organs of state and ensuring timely payments from clients; breaking down bids into smaller projects; the provision of more and detailed information for bids during the tender stage; the relaxation of unnecessary bureaucratic procedures; the provision of tax holidays; and after care and follow-up training to be provided to ensure that the small contractors remain in business. Based on these findings, impacts, and mitigation measures, the study recommends revising government policies regarding the payment of emerging contractors to address the challenge of late payments, thus prioritising timely payments for all emerging contractors and, where possible, establishing early payment arrangements; the training of emerging contractors and skills development be prioritised; and entry-level training for CIDB Level/Grade 1 contractors be implemented to upskill those emerging contractors.
Architectural considerations and resource allocation in energy efficient networking
(2022-09-29) Molefe, Mlungisi; Nleya, Bakhe
Word-wide data traffic is continuously surging, triggered mainly by the emergence of Internet-of-Things (IoT)’s services and Fog-Cloud computing-based applications. This calls for existing optical and wireless-based network infrastructures to upgrade capacity accordingly to meet required massive bandwidth demands to accommodate the ever-surging data traffic volumes. However, continuously elevating the resource requirements in terms of bandwidth provisioning implies increasing the number of en-ergy-consuming network elements, which will increase overall operational expendi-tures and carbon footprint due to extra power generation. Carbon emissions contribute significantly to global warming. To avert this, it has become necessary to promote en-ergy-efficient networking. For that reason, it necessitated an emphasis on energy effi-ciency in the design, operation, and planning of transport networks. The current dense wavelength division multiplexing (DWDM) based optical transport network architectures operate with fixed-grid employing fixed data rates. So, making this rigid approach to capacity allocation leads to inefficiencies in both spectrum allo-cation and energy usage. Flexible (or elastic) optical transport networks with flexible-grid were proposed to improve bandwidth provisioning efficiencies. Such networks support adaptive line rates and OFDM-based optical transmission, thus, this will lead to lesser network elements deployed and, consequently an improvement in energy ef-ficiency. Similarly, wireless networks, whose data traffic is mostly derived from de-vice-to-device (D2D) communication and heterogeneous 5G cellular networks (HET-NETs) have since made tremendous strides to further enhance bandwidth by way of overlaying multiple types of low power small cells in a high-power macro cell. They afford more opportunities to explore the potential cognition and cooperation diversi-ties to improve spectral efficiency. Thus in this work, we focus on both architectural design and operation of wireless and optical transport networks coupled with resource allocation. A model joint all photonic and wireless transport network architecture framework is proposed and analyzed. The architecture’s performance in servicing high-capacity mobile back-haul and front-haul traffic and real-time services support is evaluated by both analytical and simulation approaches. Various routing and switching scenarios are considered. Overall, results demonstrate that elasticity allocation of resources (bandwidth) can vastly improve the network performance in terms of spectral efficiency, reduced locking probability, and enhanced end-to-end network throughput.