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3D digital geometry designs for Poland’s syndrome using Magics and Geomagic® Freeform®
Get PDFPublished ArticlePurpose – Poland’s syndrome patients often seek medical interventions to improve their aesthetic appearances. Design and manufacturing technologies make it possible to produce custom-made implants for such medical conditions. The purpose of this study was to compare the 3D digital geometries that were designed using Magics and Geomagic® Freeform® for two anonymous case studies of Poland’s syndrome patients.
Design/methodology/approach – Computed tomography data were acquired and processed in Mimics® to isolate the pectoralis muscles in STL file format. STL files were imported into Magics and Geomagic® Freeform® to design 3D digital geometries. Thereafter, comparative analyses were performed of the respective 3D digital geometries.
Findings – The angle between the vertical and oblique planes for both sides of the thorax was 6.5° for the female and 14° for the male. The surface areas and volumes of the geometries for the female were smaller than the male. Deviation analyses between the healthy side and reconstructed side of a thorax showed that 73 per cent of the test points for Magics and 78 per cent for Geomagic® Freeform® fell in the nominated tolerance region of > 5 and <15 mm for the female. For the male, it was 83 per cent for Magics and 88 per cent for Geomagic® Freeform®.
Practical implications – Geomagic® Freeform® provides a more versatile design environment; however, the STL editor Magics may be an option to design 3D geometries for less intricate and less contoured implants.
Originality/value – This was a first attempt to compare the 3D geometries for Poland’s syndrome designed with an STL editor to those designed
with a computer-aided design program
Conversion Of Industrial Wastes Into Marginal Construction Materials
Get PDFPublished ArticleThe circular economy concept (CE) makes a salient contribution towards resource efficiency through product-life extension, redistribution/reuse, remanufacturing, and recycling as well as re-engineering of organizational processes. The construction industry is renowned for its influence on the attainment of society’s sustainable development (SD) aspirations. As such, there is a need for the industry to embrace CE principles. Yet, the uptake of these principles has not been widely reported in the context of developing economies where greenfield construction activities are burgeoning. This observation gives rise to this study. This article reports on the findings of an investigation into the utility of industrial wastes in the production of marginal construction material. To achieve this objective, a thorough geotechnical evaluation of a selection of readily available industrial wastes such as dolomitic waste (DW), silica fume (SF), and river sand (RS) deployed in different ratios according to the mass percentage of the fly ash (FA) waste to produce FA bricks was conducted. Findings suggest that the utilization of these industrial wastes in the production of FA bricks did not only portray some outstanding characteristics but also showed potential to make salient contributions to society’s sustainable aspirations
An improved and consistent approach to estimate catchment response time parameters: case study in the C5 drainage region, South Africa
Get PDFPublished ArticleLarge errors in estimates of peak discharge in medium to large catchments in
South Africa can be largely ascribed to significant errors in the estimation of the
catchment response time, mainly as a consequence of the use of inappropriate
time variables, the inadequate use of a simplified convolution process between
rainfall–run-off time variables, and the lack of locally developed empirical
methods to estimate catchment response time parameters. Furthermore, the use
of a typical convolution process between a single hyetograph and hydrograph to
estimate observed time parameters at large catchment scales is regarded as not
practical, as such simplification is not applicable in real, large heterogeneous
catchments where antecedent moisture from previous rainfall events and spatially
non-uniform rainfall hyetographs can result in multipeaked hydrographs.
This paper presents the development and evaluation of an alternative, improved
and consistent approach to estimate catchment response time expressed as the
time to peak (TP) in the C5 secondary drainage region in South Africa, while the
interrelationship, similarity and proportionality ratios between TP and the conceptual
time of concentration (TC) and lag time (TL) are also investigated
Self-directed learning - fashionable among all first-year African engineering students?
Get PDFPublished ArticleSelf-directed learning requires students to take ownership of their own learning, to become agents in the learning process, to engage in active learning and to enjoy the satisfaction of learning. This may be achieved in a project-based learning module, where students need to demonstrate a number of graduate attributes. However, it has been reported that undergraduate students struggle with self-directed and project-based learning. The research question, therefore, arises Is self-directed learning fashionable among all undergraduate first-year African engineering students who enrol for a project-based learning module in South Africa? A descriptive case study is used, where quantitative data is derived from the Williamson self-rating scale of self-directed learning (SRSSDL). Top responses suggest that students are aware of their responsibility for their own learning and that they should decide on their own learning strategies. One of the lowest responses suggests that students are finding it challenging to pursue learning among different cultures. Results further indicate that two out of every three students rated themselves as high-level self-directed learners, with 88% of these students successfully completing the module. It is recommended to educate first-time entering engineering students in how to successfully deal with cultural diversities, which is a requirement of self-directed learning
Optimal Energy Management Modelling Of A Grid-Connection Micro-Hydrokinetic With Pumped Hydro Storage
Get PDFThesisThe pressure on greenhouse gases (GHGs) emission reduction and energy deficit crisis are of global concern. The ever increasing energy demand due to population growth as well as industrial and commercial business developments, leads to energy deficit crisis for electric utility operators around the globe. This generates an increased probability of grid instability and blackout challenges. Hence, this promotes the requirement for the additional fossil fuel power plants, leading to electricity price increase for consumers, due to high investment cost and the rising fossil fuels prices. The exploitation of an onsite grid-connected renewable energy (RE) system may mitigate all of the above-mentioned challenges.
However, the intermittent nature of RE resources (such as solar, wind, hydro, geothermal and marine) leads to a challenge of high uncertainty output power. Hence, power demand cannot be reliably met, due to daily or seasonal weather changes. Therefore, a stand-alone RE system should comprise of an energy storage system (ESS), to store surplus energy for later use when the power demand is more than the generated output power. Additionally, a grid-interactive RE system should also comprise of the ESS, due to the variable tariff rates imposed by utility companies around the globe. The aim is to store excess energy during low-priced off-peak periods, for later use during high-priced peak periods. Hence, minimal electricity bill may be achieved by the consumers. The utility grid operator may also reap a benefit of a reduced blackout probability, especially during peak demanding periods.
Among various RE technologies, hydrokinetic is a promising RE solution to be exploited in areas with flowing water resources, such as rivers, tidal current or artificial water channels. It is easily predictable and has proved to generate electricity at flowing water speeds, ranging from 0.5 m/s and above. It has proved to generate electricity markedly better and affordable than solar and wind energy systems. Furthermore, it has proved to operate cost-effectively, if it comprises of a pumped-hydro storage (PHS) system instead of a battery-based storage system.
Rural consumers, such a farms, industries and mines situated in close proximity to flowing water resources, may make use of a grid-connected micro-hydrokinetic-pumped-hydro-storage (MHK-PHS) system to reduce electricity bills and sell the excess energy to the grid. However, a grid-connected MHK-PHS system requires a complex optimal energy management system, instead of expecting a consumer to respond to a change in real-time electricity price. The system should allow for optimal energy storage and sales, while ensuring that the consumer load demand is met at all times, by considering variable time-of-use (TOU) tariffs and load demand uncertainties that might take place in real-time context.
This work deals with optimal energy management of a grid-connected MHK-PHS system, under different demand seasons for different load demand sectors, through the consideration of variable TOU tariffs. The aim is to minimize the customer electricity bills if the proposed system is approved to be non-interactive or interactive with the utility grid. Additionally, the alternative aim is to maximize the energy sales into the grid, if the system is grid-interactive.
The results have proved that the developed optimization-based model is capable of minimizing the grid-cost, particularly during expensive peak-periods. Furthermore, the energy sales revenue has been maximized during peak-periods. Sundays have proved to lead to the largest amount of grid-power storage into the storage system, as compared to other days of the week. The industrial load profile led to the low net income, since most energy sales take place during the evening peak hours, instead of morning peak hours.
However, if the load demand uncertainty constraint is considered, the above-mentioned open-loop optimization-based model has been unable to optimize the power flow. This led to the unmet load demand difficulty, as well as the excessive supply of power. Hence, an additional control model has been developed to assist the open-loop optimization-based model, to handle the load demand uncertainty disturbance in real-time context. The control model proved to mitigate the issue of both unmet load demand and excessive supply of power through the application of a rule-based algorithm. Additionally, a higher energy savings was achieved through the successful reduction of the excessively supplied power
Sustainable design of built infrastructure and engineering services for South African universities
Get PDFPublished ThesisUniversities have made great strides in research and the development of new knowledge. They are known as centres of enlightenment. However, there is a need for universities to lead by example in other respects, in particular in limiting the environmental impact on cities. This is in respect of the sustainability of built infrastructure and the services provided on campuses, in the wake of challenges of climate change. Practical applications of research in the areas of high-performance buildings, can impact a city positively. Evidences from literature indicate that most of the South African cities were poorly designed from an ecological perspective and have large environmental impacts. New building standards have been recommended but are not comprehensive enough to address problems related to the performance of university buildings and infrastructure. Therefore, the aim of this research was to develop an appropriate model for building performance evaluation in higher education institutions based on assessment of parameters for achieving Energy Efficiency (EE), Indoor Environmental Quality (IEQ) and Water Use Efficiency (WUE). The study was executed by multiple case study approach because it permitted case studies of three university campuses in South Africa. The target universities constituted the units of analysis and therefore provided opportunity for in-depth assessment of building parameters of size, orientation, fenestrations, building materials, type of ventilation, building function, type of lighting, and behaviour of occupants to determine their effects on the categories of EE, IEQ and WUE. Data collection included both qualitative and quantitative approaches, which were used to establish relationships between the various parameters and how they affect EE, which in turn is influenced by WUE which affects IEQ. A system dynamic model was used to determine causal relations of the building parameters EE, IEQ and WUE. This approach constitutes an innovative and pioneering contribution to building performance evaluation. The study has established a basic level of awareness and understanding among design- and construction practitioners of the importance of the use of System Dynamics in building performance evaluation, which can be used as a tool for delivering strategic objectives in the preliminary designs of educational buildings and infrastructure. The results of the study contribute to building guidelines for sustainable design of educational neighbourhoods for the transformation of campuses, which in turn can motivate beneficial changes for more sustainable performance of the built facilities
Sustainable maintenance guidelines of non-toll roads in South Africa
Get PDFPublished ThesisRoads are important national assets and are central to economic and social development. There is an essential need for regular road maintenance to keep them operative. Limited budgets for road maintenance are the main challenge facing road agencies such as SANRAL to meet their performance obligations. This is because of competition from other services such as education, health, etc. At the same time, another challenge is the ability of road maintenance activities to contribute to environmental sustainability since road maintenance adversely impacts land and water resources and the discharged areas. This has led to calls for incorporating sustainability principles into road maintenance activities.
This research focuses on developing practical guidelines for sustainable road maintenance. It is also focused on the understanding of how road maintenance can minimize environmental impact, particularly in South Africa. The study was carried out through interviews, questionnaires, archives and journals on road maintenance. Interviews were conducted with people involved in road maintenance. Questionnaires were distributed to road users who constantly use non-toll roads. The type of road involved in this study was National Non-Toll roads under the jurisdiction of SANRAL. The data collected were analysed and the results have proved there is a need for sustainable funding for non-toll road maintenance
THE NATURE AND PREVALENCE OF GANG RELATED VIOLENCE ON LEARNERS IN SECONDARY SCHOOLS IN THE LEJWELEPUTSWA DISTRICT
Get PDFPublished ThesisThis study is based on the field of education which explores the nature and prevalence of gang related violence on learners in secondary schools in Lejweleputswa district. Therefore, the aim of the study was to undertaken to demonstrate that learners at secondary schools in the Lejweleputswa district experience different forms of violence of which gangsterism is mostly feared. The Bronfenbrenner’s Ecological Systems theory was discussed in order to understand the manifestation of gang violence on learning and teaching in secondary schools.
In order to achieve the aim of this research study a mixed methods research design was employed, using quantitative and qualitative research approaches. In the quantitative research, 241 learners from grade 8-11 participated using a closed-ended questionnaire and in the qualitative research two focus groups of 16 learners (8 each per focus group) participated. Furthermore, the research study used document analysis in the form of school incident logbooks, learners’ school code of conduct on learner discipline triangulated against the South African Schools Act, 84, 1996 and the South African Constitution, Act 104, 1996. Data for quantitative analysis was used by means of inferential statistics in order to explain patterns of responses of learners in relation to different sections of the questionnaire that they responded to. Data was collected through closed-ended questionnaires was analysed by the use of Statistical Package for Social Sciences (SPSS) with the assistance of a qualified statistician. Both descriptive and inferential statistics were used. Data collected by the use of quantitative was further subjected to a Pearson correlation test to establish the strength of gang related violence on learners on dependent variables such as, fear of physical threat, personal property being stolen, being assaulted, and etc. Thematic analysis was used for the qualitative data. The qualitative data was used to triangulate the extent to which prevalence of gang related violence is a threat to learning and teaching as well as the physical and emotional well-being the learners.
The findings of the research established the following: there nature of gang related violence exist in schools and around the school premises. Gang related violence in school is influenced a number of factors such as lack of physical security at the schools, and easy access to drugs such as alcohol. Vandalism of school property is noted by learners as having impact on learning and teaching. Prevalence of gang who are mainly juvenile are rampant and identified by learners using different names, implying territorial gangs. The research study recommends that schools, police and parents should work together to fight against gang related violence in schools.
Keywords: Gang related violence; Ecological Systems theory; Education; Safety and security; the Constitution, Vandalism
Development of an integrated disaster risk management model for the municipalities in the Free State Province
Get PDFPublished ThesisAlthough South Africa’s Disaster Risk Management legislation is internationally recognised, its implementation strategies are ineffective, which exposes vulnerable communities to the ravages of weather-related disasters. Climate change also contributes to weather-related disasters such as floods, droughts and fires, posing a serious threat to sustainable development and poverty alleviation in South Africa. A growing body of literature recognises the origins of the disasters, preparedness programmes and the disaster management cycle, yet there is a paucity of research on developing a model for municipalities to understand the basic tenets of Disaster Risk Management. The aim of the study is to contribute positively to the improvement of Disaster Risk Management by developing an integrated Disaster Risk Management model that would assist municipalities in the Free State Province to plan, implement and manage disasters risks effectively. The proposed integrated Disaster Risk Management model is based on the Cuny Comprehensive and Manitoba models and which comprises three critical elements: Hazard Analysis, Risk Management and Operations Management. The empirical study used a mixed method approach with a pragmatic paradigm. Data sets were processed using the Statistical Package for Social Sciences (SPSS 24), achieving a coefficient correlation of 0.74 using the Cronbach’s alpha as a test measure. The study found that 41% of the respondents are qualified up to Level 6 or higher on the National Qualification Framework, 79% were employed at operational level, and 48% were employed at strategic level with 6-10 years’ experience in Disaster Risk Management. Another finding is that in the Free State Province, compliance with Disaster Risk Management, the DMA (2002) and the NDMF (2005), ranges between 35% and 57%. The results of the qualitative data show that the majority of the respondents agree that an integrated Disaster Risk Management model is necessary for a uniform approach to Disaster Risk Management in the Free State Province. The study concluded that it is necessary for the development and implementation of an integrated disaster risk-management model to render effective disaster-risk management services in the Free State Province
Investigation of recycling perspectives of grey water for resource recovery in Witbank, South Africa
Get PDFPublished ThesisSouth Africa is a water scarce country. The demand for water is exceeding the supply significantly in some of the cities of the country. Simultaneously, a significant amount of grey water is generated by the households in the cities. Consequently, an argument has emerged that if grey water is treated and re-used for domestic use purposes, then it can contribute to the alleviation of the challenges to meet the water demand. Besides, grey water also constitutes significant amount of resources such as Nitrogen, Phosphorous and Potassium. Therefore, a study was done by considering the city of Witbank of the Mpumalanga Province in South Africa in order to examine the quality (impurities and nutrient content) of grey water generated in the study area, explore the appropriate treatment processes to treat the grey water to and to quantify the availability of Nitrogen, Potassium and Phosphorus so that resources such as water and chemical resources (Nitrogen, Potassium and Phosphorus) can be recovered from grey water. The study was motivated by the need to reduce the high demand for scarce fresh water and the amounts of generated waste water, and a resource recovery through recycling process can ease the pressure on the environment.
Grey water from bathrooms, showers, kitchens, laundry and sinks were collected from domestic water users of Witbank Mpumalanga Province, based on the location of the area such as central areas, upscale development and township of the city Witbank. Grey water samples were collected across the four seasons of the year and analysed in the laboratory for physical, chemical, operational, microbiological and resource content before and after treatment processes using various treatment combinations such as aerobic screening (AS), Multimedia Filtration (MMF), Ultraviolet radiation (UV) and Chlorination (CL). After treating grey water with a combination of MMF, AS and UV, the physical, chemical, operational and microbiological characteristics of grey water are compared with the standards recommended by the Department of Water Affairs and National Standards Specifications of South Africa. Also, a household survey targeting areas of Witbank as water users was carried out to collect household data relating to socio-economic characteristics and water demand, water supply scenarios. The data collected was statistically analysed.
The results of the survey indicated that upscale development areas, had the highest income and household water usage followed by central areas, then townships and lastly the city. There was a significant (p < 0.05), correlation between income and water consumption. There was also a significant, positive (p < 0.05) correlation between income and grey water production. Household surveys indicated a significant, positive (p < 0.05) correlation between income, water consumption and grey water production. The results also confirmed that income, water consumption and grey water production across upscale development, city, the townships and central areas in Witbank were significantly (p < 0.05) different.
Regression analysis of income as an independent variable and water demand as a dependent variable indicated a linear and significant causal correlation between income and household water demand exists.
Results of the experimental study indicated that the physical, chemical, operational alert and microbiological characteristics of grey water improved significantly to fall within the standard stipulated by the Department of Water Affairs after subjecting untreated grey water to individual and a combination of aerobic screening (AS), Multimedia Filtration (MMF), Ultraviolet radiation (UV) and Chlorination (CL) treatment processes. The grey water also contains significant amount of Nitrogen, Potassium and Phosphorus. Therefore, if recycling of grey water is conducted appropriately then quality water for domestic use can be recovered and re-used. Also, there is a potential for recovery of significant amount of the chemical resources such as Nitrogen, Potassium and Phosphorus