Research Publications (Engineering and Built Environment)

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Application of mine tailings sand as construction material : a review
(EDP Sciences, 2022) Ikotun, Jacob; Adeyeye, Rhoda; Otieno, Mike
Tailings are found during the exploration and processing of mineral ores. They contain a mixture of grounded rocks, processed effluent, and some trace elements that have the potential to damage the environment. Recent urbanisation has led to a large stockpile of tailings in many mining environment constituting health hazard. It becomes very important to develop disposal techniques that will reduce the huge mountain of tailings in mining environment. One of such method is the application of tailings in sustainable concrete production. It is shown that physical and chemical characteristics of tailings are comparable to crusher sand used in engineering construction and therefore, tailings can be used to partially replace sand in bituminous and concrete mixtures. In this review, specific interest has been given to iron, copper, and gold tailings, this is due to their dominance in mining areas of Kwa-Zulu Natal province of South Africa.
Balancing between demand and trading in microgrids
(IEEE, 2020-01) Gomba, Masimba; Chidzonga, Richard; Nleya, Bakhe; Khumalo, Philani
The envisaged future generation power or smart grid (SG) will incorporate ICT technologies as well as innovative ideas for advanced integrated and automated power systems. The bidirectional information and energy flows within the envisaged advanced SG together with other aiding devices and objects, promote a new vision to energy supply and demand response. Meanwhile, the gradual shift to the next generation fully fledged SGs will be preceded by individual isolated microgrids voluntarily collaborating in the managing of all the available energy resources within their control to optimally serve both demand and distribution. In so doing, innovative applications will emerge that will bring numerous benefits as well as challenges in the SG. This paper introduces a power management approach that is geared towards optimizing power distribution, trading, as well as storage among cooperative microgrids (MGs). The initial task is to formulate the problem as a convex optimization problem and ultimately decompose it into a formulation that jointly considers user utility as well as factors such as MG load variance and associated transmission costs. It is deduced from obtained analytical results that the formulated generic optimization algorithm characterizing both aggregated demand and response from the cooperative microgrids assist greatly in determining the required resources hence enabling operational cost viability of the entire system.
Characteristics of greywater from different sources within households in a community in Durban, South Africa
(IWA Publishing, 2017) Bakare, Babatunde F.; Mtsweni, Sphesihle; Rathilal, Sudesh
The reuse of greywater is steadily gaining importance in South Africa. Greywater contains pollutants that could have adverse effects on the environment and public health if the water is not treated before reuse. Successful implementation of any greywater treatment process depends largely on its characteristics in terms of the pollutant strength. This study investigated the physico-chemical characteristics of greywater from different sources within 75 households in a community in Durban, South Africa. The study was undertaken to create an understanding of greywater quality from different sources within and between households. Greywater samples were collected from the kitchen, laundry and bathing facilities within each of the households. The samples were analysed for: pH, conductivity, turbidity, total solids, chemical oxygen demand (COD) and biological oxygen demand (BOD). There was a signiﬁcant difference in the parameters analysed between the greywater from the kitchen compared with the greywater from the bathtub/shower and laundry. It was also observed that the characteristics of greywater from the different households varied considerably. The characteristics of the greywater obtained in this study suggest that the greywater generated cannot be easily treatable using biological treatment processes and/or technologies due to the very low mean BOD : COD ratio (<0.5).
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)
Comparative study of binary classifiers for reducing false negative detection of melanoma in skin lesions
(IEEE, 2022-10-27) Jooravan, Amith; Reddy, Serendra; Pillay, Nelendran
Reliable and accurate classification of a skin lesion is essential to the early diagnosis of skin cancer, especially melanoma. Traditional classification methods require performing a biopsy on the lesion. The overlap of benign and malignant clinical features may lead to incorrect melanoma diagnosis and/or excising an excessive number of benign lesions. This paper focuses on the use of machine learning to aid physicians with the non-invasive classification methodology of skin lesions, whilst prioritising the minimization of false negative classification. The clinical features used are based on the ABCD rule, representing the asymmetry, border, colour and diameter of the lesion. The dermoscopic images chosen are of melanoma lesions less than 0,76mm in thickness which corresponds to the early stages of cancer. The investigated classification methods include K-Nearest neighbours (KNN), Naïve Bayes and linear support vector machine. (LSVM). This research proposes the use of a LSVM machine learning algorithm to classify a skin lesion as being either melanoma or non-melanoma with the lowest false negative rate of the investigated classification. Classification accuracy of 85% and a false negative rate of 5% is achieved.
Correlations for the prediction of NTU and mass transfer coefficient for a VPE
(South African Institute of Chemical Engineers, 2011) Rathilal, Sudesh; Carsky, Milan; Heyberger, A.; Rouskova, M.
Liquid-liquid extraction is the separation of the constituents of a liquid solution by contact with another insoluble. The reciprocating column (RPC) and vibrating plate column (VPE) are two types of mechanically aided columns. This paper aims at developing appropriate correlations for the prediction of NTU/HETS and the mass transfer coefficient, kox for the VPE based on the agitation level of the plates (af – the product of frequency and amplitude of the plate motion), the plate spacing and the flow rates which will allow for the simplification in the design of this type of column. The system chosen was the acetone-toluene-water system (standard test system – EFCE) with the acetone in toluene forming the feed that is dispersed in the column as it moved upward while the water moved as a continuous phase down the column. Experiments were conducted to evaluate the hydrodynamics of the droplets moving up the column and to evaluate the mass transfer that occurs (in order to evaluate NTU, HTU and kox) while varying the agitation levels and spacing of the plates in the column. Successful correlations were developed using some of the experimental data and these correlations were verified with additional data.
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.
Designing environmentally sound engineering solutions on infrastructure projects
(World Academy of Research and Publication, 2013-12) Saroop, Shian Hemraj; Allopi, Dhiren
There is a growing complexity of infrastructure planning and the need for coordination of design and environmental requirements. The lack of appropriate tools and skills for sustainable Infrastructure design is often seen as a barrier to sustainable design. Infrastructure development has been focused mainly on financing issues and engineering aspects in the region. 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. Improvement in the awareness of eco-efficiency concepts is urgently needed among policy-makers, planners and decision-makers. However, the criteria applicable to, and measures for developing eco-efficient and sustainable infrastructure are yet to be fully identified (United Nations Economic and Social Commission for Asia and the Pacific, 2006). Engineers need to look at greener technologies rather than just using traditional engineering solutions. The 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. This paper discussed the application of ‘green technology’ on infrastructure design projects. It gives an overview of the proposed Green Township Infrastructure Design toolkit and looks at a number of recommended green practices on infrastructure services design, that are environmentally sound placing, fewer burdens on the environment. It would ensure a sustainable design of township infrastructure services enforcing the consideration of resources, environmental impacts of design decisions, ecologically sensitivity, innovation, maintenance and materials, at the design stage of a project.
Energy demand and trading optimization in isolated microgrids
(IEEE, 2020-04-30) Chidzonga, Richard; Gomba, Masimba; Nleya, Bakhe
Future generation or smart grid (SG) will incorporate ICT technologies as well as innovative ideas for advanced integrated and automated power systems. The bidirectional information and energy flows within the envisaged advanced SG together with other aiding devices and objects, promote a new vision to energy supply and demand response. Meanwhile, the gradual shift to the next generation fully fledged SGs will be preceded by individual isolated microgrids voluntarily collaborating in the managing of all the available energy resources within their control to achieve optimality in both demand and distribution. In so doing, innovative applications will emerge that will bring numerous benefits as well as challenges in the SG. This paper introduces a power management approach that is geared towards optimizing power distribution, trading, as well as storage among cooperative microgrids (MGs). The initial task is to formulate the problem as a convex optimization problem and ultimately decompose it into a formulation that jointly considers user utility as well as factors such as MG load variance and associated transmission costs. It is deduced from obtained analytical results that the formulated generic optimization algorithm characterizing both overall demand and response by the cooperative microgrids assist greatly in determining the required resources hence leading to cost effectiveness of the entire system.
An Eulerian approach to soil impact analysis for crashworthiness applications
(Elsevier, 2016) Evans, Wade Robert; Johnson, D.; Walker, Mark
The primary motivation of this study was the development and implementation of an explicit nonlin-ear dynamic ﬁnite element based methodology for investigating the crashworthiness of small lightweight composite aircraft impacting into soft soil. The technique used to characterise and validate a numerical model for soft soil as an impact terrain is the focus of this paper. The technique used was primarily based on the use of a time explicit Eulerian-based ﬁnite element analysis code, and this technique was dem-onstrated through the ﬁnite element analysis of penetrometer drop tests into soft soil. The Eulerian-based ﬁnite element approach was considered rather than the more commonly used Lagrangian-based ﬁnite element approach in order to reduce numerical instabilities which often occur with the use of La-grangian solvers when considering problems with large deformations, which is a characteristic of crash analyses. Validation of the numerical model was based on previously published work in which pen-etrometer drop tests into soft soil/clay were performed at the Utah Test and Training Range. Experimental data were presented in this work, as well as a ﬁnite element modelling approach based on Lagrangian methods. Based on the results obtained it was concluded that an Eulerian-based approach to soft soil impact analysis, for crashworthiness applications, is valid. Greater model ﬁdelity may possibly be gained by further investigation of the drop test methodology, viscosity effects, variation of soil mechanical prop-erties through the depth range, and strain rate effects.
Exploring the informal communication of driver-to-driver on roads : a case study of Durban city, South Africa
(The Road Association of Serbia Via-vita, 2021-12-17) Adedayo Adedeji, Jacob; Feikie, Xoliswa
Road traffic fatality is rated as one of the ten causes of death in the world and with various preventive measures on a global level, this prediction is only placed on flat terrain and didn’t reduce. Nevertheless, road users’ communication is an essential key to traffic safety. This communication, be it formal or informal between the road users is an important factor for smooth traffic flow and safety. Communication language on roads can be categorized into; formal device-based signal (formal signal), formal hand signal (formal signal), informal device-based signal (informal signal), and informal gesture-based signal (everyday signal). However, if the intent of the message conveys is not properly understood by the other road user, mistakes and errors may set in. Overall, the formal signal is based on explicit learning which occurs during the driving training and the license testing process and the informal, implicit learning occur during the actual driving process on the road unintentionally. Furthermore, since the informal signal is not a prerequisite to driving or taught in driving schools, novice drivers are clueless and thus, might have contributed to errors and mistakes which leads to traffic fatalities. Therefore, this study seeks to document the informal means of communication between drivers on South African roads. Consequently, a qualitative semi-structured interview questionnaire would be used in the collection of informal signals, which were predominantly used on South African roads from driving instructors and thereafter, a focus group of passengers’ car, commercial and truck drivers will be used to validate the availability and their understanding of these informal signals using a Likert-type scale for the confidence level. In conclusion, the information gathered from this study will help improve road safety and understanding of road users especially drivers on the necessity of communication and possible adaptation for other developing countries.
Finding solid ground : law enforcement, key populations and their health and rights in South Africa
(International Aids Society, 2016) Scheibe, Andrew; Howell, Simon; Muller, Alexandra; Katumba, Munyaradzi; Langen, Bram; Artz, Lillian; Marks, Monique Michal
Introduction: Sex workers, people who use drugs, men who have sex with men, women who have sex with women and transgender people in South Africa frequently experience high levels of stigma, abuse and discrimination. Evidence suggests that such abuse is sometimes committed by police officers, meaning that those charged with protection are perpetrators. This reinforces cycles of violence, increases the risk of HIV infection, undermines HIV prevention and treatment interventions and violates the constitutional prescriptions that the police are mandated to protect. This paper explores how relationship building can create positive outcomes while taking into account the challenges associated with reforming police strategies in relation to key populations, and vice versa. Discussion: We argue that relationships between law enforcement agencies and key populations need to be re-examined and reconstituted to enable appropriate responses and services. The antagonistic positioning, ‘‘othering’’ and blame assignment frequently seen in interactions between law enforcement officials and key populations can negatively influence both, albeit for different reasons. In addressing these concerns, we argue that mediation based on consensual dialogue is required, and can be harnessed through a process that highlights points of familiarity that are often shared, but not understood, by both parties. Rather than laying blame, we argue that substantive changes need to be owned and executed by all role-players, informed by a common language that is cognisant of differing perspectives. Conclusions: Relational approaches can be used to identify programmes that align goals that are part of law enforcement, human rights and public health despite not always being seen as such. Law enforcement champions and representatives of key populations need to be identified and supported to promote interventions that are mutually reinforcing, and address perceived differences by highlighting commonality. Creating opportunities to share experiences in mediation can be beneficial to all role-players. While training is important, it is not a primary mechanism to change behaviour and attitudes.
Hydrological characterization of twelve water catchments in Nigeria
(AJER, 2014-01) Afolayan, S.O.; Adeyemo, Josiah; Otieno, Fredrick Alfred O.; Ojo, Olumuyiwa I.
Twelve water catchments (WCs) in Ogbomosho, south west of Nigeria were evaluated for their hydrological characterization with respect to domestic and irrigation activities. Both physiochemical and biological parameters (limnological properties) were determined which include pH, total alkalinity (TA), CO32-, HCO3-, NO3-N, SO42-, N, P, K, Na, Ca, Mg, dissolved oxygen (DO), electrical conductivity (ECw), biochemical oxygen demand (BOD), total solids (TS), total dissolved solids (TDS), chlorophyll a,b,c and phaeophytin. Temperature fluctuation of the water catchments was measured in-situ to avoid samples coming into contact with the surrounding air using mercury in glass thermometer. Soil samples collected from the bottom of the water catchments were determined for chemical properties such as N, P, K, Na, Ca, Mg, and SO4-2 following recommended procedures. These parameters were investigated based on the perceived research consent of their efficacy in characterizing water catchments hydrologically along safety and pollution divides. The limnological properties were configured into ranking compared with standards to evaluate the degree of contamination or suitability of the WCs for domestic and irrigation purposes. Results obtained indicated pH values of the catchments ranging from 5.8 to 7.4 with corresponding TA between 0 and 296 mgL-1 suggesting high level of dissolved carbon dioxide (DCO2) and traces of untreated wastewater in most of the catchments. Based on ranking of the limnological properties of the WCs, WC4, WC5, WC6 recorded indices between 65 and 95 signifying that cumulatively these three WCs were more prone to pollution and could affect human health at consumption while WC2, WC3, WC 7 and , WC 10, aligned between 95 and 120 indicating mild to medium pollution and WC1, WC 11, and WC 12 oscillated between 120 to 145 picturing WCs approaching standards (132) while WC8 ranged between 145 and 170 revealing WC 8 as catchment with little or no tendency for hazards at drinking. Similarly, WC2, WC8, recorded soil reference (SR) between 50 and 60 suggesting possible interference of organic decomposition between the soil stratum and water in the catchment, however, WC1, WC4, WC5, WC6, WC7 and WC 12 recorded SR between 40 and 50 showing possible adjustment of the soils in the WCs of various salinity levels and WC 3, WC9, WC 11 revolving between 30 and 40 projecting the WCs with minimal pollution. Moreover, WC 10 only recorded value between 20 and 30, an inference of the soil stratum void of absolute contamination. Generally, WC2, WC8, appeared polluted both in limnological properties and basic soil conditions while WC9, WC10, WC11, and WC3 reflected high scale of ranking on limnological properties with low scale of SR possibly indicating little or no interaction between the soil base and the water in the catchments. Contrary wise, WC6 was high in SR but low in limnological properties. This trend suggests the presence of oxygen saturation in some of the WCs. Overall results indicated that WC4, WC5, WC6 require major water treatment prior to its usage for irrigation to avoid salt deposition at the crop root base, while WC2, WC3, WC7, WC9 and WC10 were considered relatively safe for drinking. WC1, WC11, WC2 requires some measure of precaution before drinking, however, WC12, and WC 8 could be consumed with little or no fear of infection.
Infinite dilution activity coefficient measurements for 1-Methyl-4-(1-methylethenyl)-cyclohexene as a green solvent for separation
(American Chemical Society (ACS), 2022-04-14) Mbatha, Banzi Patrick; Ngema, Peterson Thokozani; Nkosi, Nkululeko; Ramsuroop, Suresh
Infinite dilution activity coefficients for various solutes, which include alkanes, alkenes, alkynes, cycloalkanes, heterocycles, alcohols, aromatics, ketones, ethers, nitrile, and water, in a 1-methyl-4-(1-methylethenyl)-cyclohexene solvent were measured using gas-liquid chromatography at 303.15, 313.15, and 323.15 K. The focus of this study was to assess 1-methyl-4-(1-methylethenyl)-cyclohexene as a green solvent for separation processes. 1-Methyl-4-(1-methylethenyl)-cyclohexene, a nonpolar monoterpene solvent extracted from essential oils of citrus peels, was investigated as an alternative solvent to currently employed conventional organic solvents in separation processes. Through experimental infinite dilution activity coefficients, γ13∞, the values of partial molar excess enthalpy at infinite (δHiE,∞) were obtained using the Gibbs-Helmholtz equation. The infinite dilution selectivity (Sij∞) and capacity (δkj∞) values were calculated from the experimental limiting activity coefficients and were compared with deep eutectic solvents, ionic liquids, and industrial solvents. From this study, it was observed that 1-methyl-4-(1-methylethenyl)-cyclohexene is not suitable to be used as an alternative for separation processes. In addition, activity coefficients at infinite dilution of different organic solutes in hexadecane were measured at various temperatures to validate the reliability and accuracy of gas-liquid chromatography. Finally, the experimental data were modeled using Aspen Plus, compared with experimental data, and found to be in good agreement.
Machine learning for road traffic accident improvement and environmental resource management in the transportation sector
(MDPI AG, 2023-02) Megnidio-Tchoukouegno, Mireille; Adedeji, Jacob Adedayo
Despite the measures put in place in different countries, road traffic fatalities are still considered one of the leading causes of death worldwide. Thus, the reduction of traffic fatalities or accidents is one of the contributing factors to attaining sustainability goals. Different factors such as the geometric structure of the road, a non-signalized road network, the mechanical failure of vehicles, inexperienced drivers, a lack of communication skills, distraction and the visual or cognitive impairment of road users have led to this increase in traffic accidents. These factors can be categorized under four headings that are: human, road, vehicle factors and environmental road conditions. The advent of machine learning algorithms is of great importance in analysing the data, extracting hidden patterns, predicting the severity level of accidents and summarizing the information in a useful format. In this study, three machine learning algorithms for classification, such as Decision Tree, LightGBM and XGBoost, were used to model the accuracy of road traffic accidents in the UK for the year 2020 using their default and hyper-tuning parameters. The results show that the high performance of the Decision Tree algorithm with default parameters can predict traffic accident severity and provide reference to the critical variables that need to be monitored to reduce accidents on the roads. This study suggests that preventative strategies such as regular vehicle technical inspection, traffic policy strengthening and the redesign of vehicle protective equipment be implemented to reduce the severity of road accidents caused by vehicle characteristics.
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.
A meta-analysis of channel switching approaches for reducing zapping delay in internet protocol television
(Institute of Advanced Engineering and Science, 2021-06) Adeliyi, Timothy T.; Ogunsakin, Ropo E.; Adebiyi, Marion O.; Olugbara, Oludayo O.
Channel zapping delays are inconveniences that are often experienced by the subscribers of Internet protocol television (IPTV). It is a major bottleneck in the IPTV channels switching system that affect the quality of experience of users. Consequently, numerous channels switching approaches to minimize zapping delay in IPTV have been suggested. However, there is little knowledge reported in the literature on the determination of the strength of the evidence presented on the approaches of reducing zapping delay in IPTV, which is the prime purpose of this study. The extraction of the relevant articles was designed following the technique of preferred reporting items for systematic reviews and meta-analyses (PRISMA). All the included research articles were searched from the widely used databases of Google Scholar, and Web of Science. All statistical analyses were performed with the aid of the random-effects model implementation in Stata version 15. The overall pooled estimated delay component was presented in forest plots. Overall, thirteen studies were included in the meta-analysis and the overall pooled estimate was 10% (95% CI: 7%, 30%)). Experimental studies have shown that virtual elimination of IPTV zapping delay is possible for a relevant chunk of channel switching requests.
A mutual lightweight authentication scheme for fog-cloud-based e-health services
(Turkish Online Journal of Qualitative Inquiry (TOJQI), 2021-12-30) Nleya, Bakhe
The new version Internet network, now referred to as the Internet of Things (IoT) facilitates interconnectivity among various objects and devices. The introduction of both Cloud and Fog computing paradigms, device device-to-device (D2D) communication standards, as well as enabling privacy and security approaches, have all contributed to the practical realization of E-health services in IoT-enabled networks. Gen-erally, Fog layer nodes are often located in public places, where they are easily accessible and thus vulnerable to various securi-ty threats. Should this occur, the current and previously gener-ated security keys, as well as device identities, must be kept secret thus ensuring anonymity, unlinkability, forward secrecy, e.t.c. Thus in this paper, we introduce an E-Health authenti-cation and security architecture for the D2D-Aided fog compu-ting model, that facilitates verification of key components such as patients and peripheral devices without involving a central-ized cloud server. This is followed by a proposal for a light-weight anonymous authentication protocol (LAAP) to carry out authentication of the various parties in an E-health system. The proposed protocol is evaluated for various scenarios in D2D-Aided fog computing. Lightweight crypto- graphic primi-tives such as exclusive-or operations and one-way hash func-tion are relied upon to facilitate the inclusion of resource-constrained end-user devices mostly incorporated in body area networks (BANs). Ultimately we carry out an evaluation of the proposed proposal in terms of its efficacy, and security. The proposed protocol is generally found to be practically feasible for implementation in E-health service infrastructures.
A pilot study into public attitudes and perceptions towards greywater reuse in a low cost housing development in Durban, South Africa
(IWA Publishing, 2016) Bakare, Babatunde F.; Mtsweni, Sphesihle; Rathilal, Sudesh
The beneﬁts of greywater reuse have been identiﬁed to include the protection of water resources, recovery of nutrients for agriculture, savings in fresh water usage, reduction in volumes of wastewater discharged into wastewater treatment works, groundwater recharge and sustainable water resource management. An understanding of public attitude and perceptions towards the reuse of greywater will help to facilitate a positive reaction to the promotion of such concepts. The study involved administering of structured questionnaires to residents within the community through ﬁeld visits. The questionnaire addressed issues related to attitudes towards the reuse of greywater, perceived advantages related to the reuse of greywater and concerns related to public health issues regarding the reuse of greywater. A total number of 346 questionnaires were administered and respondents were aged from less than 19 to over 60 years. Of the respondents, 55% were female and 45% male. The ﬁndings revealed a complex and shifting relationship between attitudes towards and perception of the reuse of greywater. This paper thus presents the ﬁndings and assesses certain aspects of greywater reuse.
Process improvement for traditional mould making process through group technology and rank-order clustering algorithm
(PONTE, 2022-06-23) Dewa, Mendon; Pancha, Uttam Bhana
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 usage of group technology and rank-order clustering algorithm as mechanisms to aid the reduction of manufacturing lead time for the traditional mould making process. 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.