Research Publications (Engineering and Built Environment)

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Comparative analysis and case study to evaluate conventional designs and environmentally sensitive infrastructure design solutions
(SAICE, 2016-08) Saroop, Shian Hemraj; Allopi, Dhiren
Globally the construction industry is one of the main contributors to the depletion of natural resources and a major cause of unwanted side effects such as air and water pollution, solid waste, deforestation, health hazards, global warming and other negative consequences. In the area of sustainability there is an urgent need to apply technologies and methods which deliver more sustainable performance in a way that is cost-effective. Sustainable, adaptive and mitigating approaches to climate change in the design of infrastructure are therefore important steering elements (FIDIC 2009)
Creating eco efficient township infrastructure projects with the use of green engineering solutions and sustainability criteria
(Institute of Municipal Enginering of South Africa, 2015) Saroop, Shian Hemraj; Allopi, Dhiren
Globally, the construction industry is one of the main contributors to the depletion of natural resources and a major cause of unwanted side effects such as air and water pollution, solid waste, deforestation, health hazards, global warming, and other negative consequences (Harvey and Wayne, 20084). As we face significant planetary issues such as global warming, it is clear that the engineering profession has a significant part to play in affecting the future of our planet. In order to stay competitive and to meet upcoming stricter environmental regulations and customer requirements, designers have a key role in designing civil infrastructure so that it is environmentally sustainable. These and other factors have compelled the engineer to design with greater care and in more detail. The changing roles of engineers will be highlighted, in order to react to changes in climate. Mainstreaming environmental aspects and incorporating the eco-efficiency concept into various stages of infrastructure development have not been considered as much as they should have been. Engineers need to look at greener technologies rather than just using traditional engineering solutions. This paper looks at the effects of climate change on infrastructure and the changing role of engineers. It aims to demonstrate the use of sustainability criteria on infrastructure projects. The use of the proposed criteria would ensure a sustainable design for township infrastructure services through the consideration of scare resources, ecological sensitivity in the design and planning of infrastructure projects. This paper focuses on the concept of eco-efficiency in infrastructure design that promotes the use of the greener engineering options, enabling him/her to choose the one likely to yield the best performance with the least environmental impact. It looks at a number of recommended green practices on infrastructure services design, that are environmentally sound placing, fewer burdens on the environment.
Effects and benefits of using high content of fly ash in concrete
(Thomson Reuters, 2016-01) Zulu, Sabelo; Allopi, Dhiren
The usage of fly ash products by the South African cement and construction industries has saved the country over 6 million tons of harmful greenhouse gas emissions. The recycling of it as cement extenders provides an immediate benefit for the environment while still improving the quality of concrete, and increasing the amount used in concrete can promote sustainable development. This study evaluated properties of 35MPa/9,5mm concrete with fly ash substituted at 30%, 40%, 50% and 60%. Increasing the fly ash content can result in more workable and less permeable concrete. The compressive strength and durability index results showed that the fly ash content can be increased beyond 50% and still achieve the required strength and produce durable concrete. Substituting high volumes of cement with fly ash in concrete can provide good quality concrete and a relief to the environment without compromising the quality and cost of concrete.
Influence of high content fly ash on concrete durability
(IJEIT, 2014-01) Allopi, Dhiren; Zulu, Sabelo
Abstract - The use of fly ash products by the South African cement and construction industries has saved the country over 6 million tons of harmful greenhouse gas emissions. Fly ash is an industrial by-product that is normally consigned to landfills and the re-use of it as cement extenders provides an immediate benefit for the environment while still improving the quality of concrete. Fly ash blended cements in concrete perform better than pure cement in providing better concrete properties. Current specifications limit the use of fly ash in concrete to 30%, although an increase of this amount can be very beneficial in concrete structures, economically and environmentally. In South Africa the durability index of concrete is commonly determined by performing the Oxygen Permeability test, Water Sorptivity test and Chloride Conductivity test, developed by the Universities of Cape Town and the Witwatersrand. Performing these tests in this study, the results obtained showed that concrete mixes with fly ash content that is higher than the specification limit can result in concrete with acceptable good durability qualities, and with age, the durability qualities are improved due to pozzolanic reactions. Substituting high volumes of cement with fly ash in concrete can provide high quality concrete and a relief in the environment without compromising the quality of concrete.
Maximization of hydropower generation from Hazelmere Dam in South Africa
(Business Perspectives, 2015) Mashiyane, Thulasizwe Innocent; Olofintoye, Oluwatosin Onaopemipo; Adeyemo, Josiah
Harnessing more energy from existing water sources within the frontier of the country is germane in capacitating the South African Governmentâ€™s commitment to reduction of the countryâ€™s greenhouse gas emissions and transition to a low-carbon economy while meeting a national target of 3 725 megawatts by 2030. This study aims to determine the amount of energy that can be generated from Hazelmere Dam on the Mdloti River, South Africa. Behavioral analyses of the Hazelmere reservoir were performed using plausible scenarios. Feasible alternative reservoir operation models were formulated and investigated to determine the best operating policy and power system configuration. The optimi-zation models were formulated to maximize hydropower generation while keeping within the limits of existing irriga-tion demands. Differential evolution algorithm was employed to search feasible solution space for the best policy. Findings suggest that if the water resource in the dam is properly managed, about 558.54 MWh of annual energy may be generated from the reservoir under medium flow condition without system failure.
Measuring infrastructure sustainability with the use of eco efficient performance criteria
(International Association of Scientific Innovation and Research, 2015) Saroop, Shian Hemraj; Allopi, Dhiren
Civil engineering projects can have significant site-specific and cumulative impacts on our ecological and social systems if not correctly planned, designed and implemented. As we face significant planetary issues such as global warming, it is clear that the engineering profession has a significant part to play in affecting the future of our planet. This paper aims to demonstrate the importance of eco efficient criteria on infrastructure projects. The use of the proposed criteria would ensure a sustainable design for township infrastructure services through the consideration of scare resources, ecological sensitivity in the design and planning of infrastructure projects. This paper also gives an overview of the proposed Green Township Infrastructure Design toolkit and promotes the use of green practices on infrastructure services design, that are environmentally sound, placing fewer burdens on the environment. This paper also compares two case studies that utilises green infrastructure criteria to rate its eco efficiency.
Modelling of solar PV under varying condition with an improved incremental conductance and integral regulator
(MDPI AG, 2022-04-01) Stephen, Akinyemi Ayodeji; Musasa, Kabeya; Davidson, Innocent Ewaen
The introduction of solar photovoltaic (PV) systems would provide electricity accessibility to rural areas that are far from or have no access to the grid system. Various countries are planning to reduce their emissions from fossil fuel, due to its negative effects, by substituting with renewable energy resources. The use of solar PV systems is expanding globally because of growing energy demands and depleting fossil fuel reserves. Grid integration of the solar system is expected to increase further in the near future. However, the power output of solar PV systems is inherently intermittent, and depends on the irradiance and the temperature operation of the solar cell, resulting in a wide range of defects. Hence, it is vital to extract peak power from the solar panel in all conditions to provide constant power to the load. This paper presents a tracking control method of the peak output power of a solar PV system connected to a DC-DC boost converter using an improved incremental conductance and integral regulator (IC + IR). The research was carried out because the solar PV output is dependent on environmental parameters, such as solar insolation and temperature. Therefore, it is pertinent to forecast the peak power point in outdoor conditions and to operate at that point, so that solar PV can produce the highest output each time it is used. A peak power point strategy that maximizes the output of a solar PV array is proposed. This method establishes the maximum output operation point under the effects of the solar insolation and the module temperature. An automatic converter restoration scheme with block/de-block signal control is proposed to protect the converters from the higher phase current, total capacitor voltage deviation, grid disturbance, and fault current. The proposed scheme also tracks the peak power point (PPP) of the solar array with stable output voltage under varying operating conditions. It reduces the error signal and ripples at the PPP during instantaneous and incremental conductance to zero. In addition, it controls the solar PV system under constantly changing climatic conditions, and thus improves the system efficiency.
Monthly stream flow prediction with limited hydro-climatic variables in the upper Mkomazi River, South Africa using genetic programming
(Parlar Scientific Publication, 2014) Oyebode, Oluwaseun Kunle; Adeyemo, Josiah; Otieno, Fredrick Alfred O.
Streamflow prediction remains crucial to decision-making especially when it concerns planning and management of water resources systems. The prediction of streamflow however, comes with various complexities arising from non-linear and dynamic nature of the climatological and hydrological factors. Several modelling studies relating to streamflow prediction have been carried out using different approaches. However, considering the non-linear and dynamic behaviour of hydro-climatological processes, a significant amount of historical data is required in all these approaches in order to achieve accurate and reliable results. Genetic Programming (GP), a computational intelligence approach based on evolutionary algorithm was employed in this study to predict the response of streamflow to hydro-climatic variables in the upper Mkomazi River in South Africa using limited amount of datasets. Historical records for a period of nineteen years (1994-2012) were used for the construction and selection of input variables into the GP vector space. Individual monthly models were employed for streamflow prediction for each month of the year. The performances of the models were evaluated using three statistical measures of accuracy. Results obtained indicate a close agreement and highly positive correlation between observed and predicted values of streamflow during the training and validation phases for all the twelve models developed. These results further confirm the efficacy of the GP approach in monthly streamflow prediction despite the use of limited amount of datasets.
On demand and supply management in domestic microgrids
(Turkish Online Journal of Qualitative Inquiry (TOJQI), 2021-12-01) Chidzonga, Richard; Nleya, Bakhe; NLEYA
Standalone or residential microgrids (MG) are becoming increasingly common. Their success is premised on optimal operational strategies like demand side management (DSM). It is not uncommon in optimization problems to deal with competing objectives in the context of multi-objective optimization. In a domestic MG, optimization objectives may encompass minimization of OPEX, maximization of consumers’ utility, and minimization of CO2 emissions etc. This article employs a technique which transforms a bi-objective energy optimization problem into a single objective problem, then solving the problem using the heuristic technique of binary particle swarm optimization (B PSO). The random phenomena associated with the statistical load profiles and multiple renewable energy sources (RESs) are modelled using established statistical approaches. Results obtained using simulation show that the pro-posed model can minimize the OPEX of isolated MG whilst simultaneously meeting the utility expectations of the consumer.
Perspectives on impact of high penetration of renewable sources on LV networks
(IEEE, 2020-08) Chidzonga, Richard F.; Nleya, Bakhe
In most countries, electricity power grids have not undergone extensive modernization and/or liberalization. They are still predominantly vertically integrated i.e. designed and opera ted top (Generation)-down (Distri bution/loads). Increasing electricity demand and rising costs are ca using congestion and strain on power distribution networks cperartens. Fossil fuels are in decline and blamed for most negative environmental l and cUmadc imp acts on world economics and societal maleficence. Through out the world they are heightened impetuses to migrate to cleaner Renewable Energy (RE) sources and incorporate more intelligence in the utilization of energy. This has birthed the concept of smart grids with high participation of various clean energy sources . Hybrid renewable energy generation (HRE) systems are complementary technologies that have potential to mitigate climatic variability effects which are still a challenge with respect to dispatchability of RE resources. The emerging smart power grids are no longer unidirectional in terms of energy Row, but also allow users to inject energy back into the grids. The bi-directional now of energy has a significant positive impact on overall systems design and operation. This article provides an overview of the preliminary work that done to assess impact scenarios on power grids with increased penetration of RE. Simulation results show possible negative factors that may affect QoS parameters of typical LV power networks.
A study on indirect tensile strength for the determination of resilient modulus of warm mix asphalt
(Elsevier BV, 2023) Kamdem, Ronald Fabrice Pouokam; Adedeji, Jacob Adedayo; Mostafa, Mohamed M. Hassan
The advent of Warm Mix Asphalt (WMA) incorporating Recycled Asphalt Pavement (RAP) as a long-term solution to partially or totally participate in remediating the problem of global warming and the regression of environmental resources has been expanding and gaining interest throughout the world. The WMA-RAP technology created as an improved WMA technology has shown to possess mechanical properties closely similar to Hot Mix Asphalt (HMA). Though searching for environmentally sustainable asphalt technologies have become vital, the quest to construct economically sustainable highways cannot be neglected. The dynamic modulus tests (DMT) is among the most accurate yet expensive laboratory tests performed to determine the resilient modulus of asphalt mixes. Therefore, this paper aims to determine the resilient modulus of asphalt mixes (WMA-RAP and HMA) through both the indirect tensile strength (ITS) and the correlation formula method (CFM) and compares them against the dynamic modulus tests method (DMTM). Furthermore, this study utilises the resilient modulus found through CFM and DMTM to predict and compare the mechanical performances of asphalt pavement systems. Finite Element Modelling (FEM) and Linear Elastic Analysis (LEA) were used to modelling and analysing the mechanical behaviour of pavement systems. Both the WMA15% RAP and WMA30% RAP samples were mixed with 50/70 grade bitumen modified with Sasobit additive. The HMA samples on the other hand were mixed with non-modified 50/70 grade bitumen. Findings show that the resilient moduli of HMA and WMA-RAP mixes obtained through CFM is 77% close to the DMTM. In addition, the HMA and the WMA-RAP pavements with CFM and DMTM resilient moduli also show very close mechanical performance. This signifies that the CFM can be used as a reliable and cost effective alternative method to determine the resilient modulus of asphalt mixes.
The use of eco efficient criteria in the design of infrastructure projects
(WITPRESS, 2016) Saroop, Shian Hemraj; Allopi, Dhiren
Globally, the construction industry is one of the main contributors to the depletion of natural resources and a major cause of unwanted side effects such as air and water pollution, solid waste, deforestation, health hazards, global warming and other negative consequences. In the area of sustainability, there is an urgent need to apply technologies and methods that deliver better and more sustainable perfor-mance in a way that is cost-effective. Sustainability, adaptive and mitigative approaches to climate change, in the design of infrastructure, are therefore important steering elements [1]. A systematic and iterative analysis of the environmental impact of various design solutions is commonly suggested for infrastructure projects, but rarely happens. The lack of appropriate tools and skills for sustain-able design was often quoted as a barrier to sustainable design [2]. To stay competitive and to meet upcoming stricter environmental regulations and customer requirements, designers have a key role in designing civil infrastructure so that it is environmentally sustainable. These and other factors have compelled the engineer to design with greater care and in more detail. The changing roles of engineers will be highlighted, to react to changes in climate. This paper aims to demonstrate the importance of eco efficient criteria on infrastructure projects. The use of the proposed criteria would ensure a sustainable design for township infrastructure services through the consideration of scare resources, ecological sensitivity in the design and planning of infrastructure projects. This paper also gives an overview of the proposed Green Township Infrastructure Design toolkit and promotes the use of green practices on infrastructure services design that is environmentally sound, placing fewer burdens on the environment.