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An Energy Efficient Electro-Hydraulic Control System For A Collaborative Humanoid Robot
Get PDFDissertationThis study presents the design of an energy efficient electro-hydraulic control system for a collaborative humanoid robot. Robots can be found in almost every aspect of our lives with different applications such as manufacturing, construction, agriculture, surgery, and transportation. The need for robots is on the rise as they perform certain tasks much faster and with more precision than humans. The lack of them having cognitive ability limits them in certain tasks as human interaction is often needed. Humans are currently better than robots in performing some tasks such as decision making and problem solving. In collaborative robotics, humans and robots are required to work together to achieve a common goal. In most cases, this is achieved by confining both entities in the same space. This allows for better accuracy for these robots with the flexibility and cognition of humans. Furthermore, research lately shows an increase in robots that use hydraulics with most showing that these hydraulics have energy saving abilities in robotic actuation. It is known that hydraulics have a high power to weight ratio thus allowing for more powerful yet compact robots to be built. An electro-hydraulic control system is thus described in this research in which the system allows the human user to manipulate the robot by having it mimic the user’s moves. This approach allows the user to not do any strenuous activities while the robot does the heavy lifting. Furthermore, the system does not need to be reprogrammed for a new task therefore reducing the reconfiguration time of the system. The proposed approach further allows the robot to work in hazardous situations while the user is in a safe environment. The system uses a proportional-integral-derivative (PID) algorithm to control a hydraulic cylinder allowing it to move with the user. Experiments performed to validate the study shows the reaction time as well as energy saving abilities of the system. Additionally, the results show that hydraulic systems have the ability to save energy during stall as well as increasing power density of the robot. Furthermore, an improved response time was recorded for the hydraulic system when being controlled by a remote operator
Investigating barriers to effective communication in the lecturing environment at CUT
Get PDFThesis (Master: Communication: Language practice)--Central University of TechnologyEffective communication in the lecturing environment plays an important role in
assisting lecturers and students in achieving educational outcomes. However, the
problematic nature of communication barriers could impede communication and lead
to ineffective teaching and learning. Consequently, ineffective communication has a
negative impact on student achievement. In contrast, effective communication could
minimise miscommunication and lead to improved student performance. As such, this
study investigated the barriers to effective communication in the lecturing
environment. A quantitative approach, using an interpretive and explorative design,
was used to investigate the extent to which communication barriers influence learners’
performance in the classroom. Data was collected using questionnaires that were
designed for lecturers and students, respectively. The study revealed that
communication barriers do in fact influence students’ performance adversely and that
they are still prevalent in the lecturing environment. The researchers recommend that
barriers should be reduced to improve learner performance
Adaptation of the community to the impact of drought on water availability in Bloemfontein, Free State Province, South Africa
Get PDFThesis (Master: Health Sciences: Environmental Health)--Central University of TechnologyBackground: Drought is considered to be a life-threatening natural disaster that results in many uncertainties. Drought has been occurring globally in the past decades due to climate change. The reduction of the availability of water in the impacted regions is one of the features of drought. Many cities in South Africa lack drought impact adaptation plans to deal with the increased water demand. Therefore, it is important to conduct drought monitoring models for adaptation in cities that lack the capacity. The study aims to determine the impacts of the recent droughts on the availability of water and the adaptation of the community toward water restrictions. To achieve this aim, five objectives were devised; namely: (i) To determine the impact of drought on the Bloemfontein area by assessing the annual meteorological data, rainfall levels as well as dam levels of Bloemfontein from 2016 to 2018, (ii) To assess the household water use behaviour of the Bloemfontein community members after the implementation of water restrictions, (iii) To evaluate the annual data on water use in Bloemfontein from 2016 to 2018, and (iv) To review the Disaster Risk Management Plan that is currently in place in the Mangaung Metropolitan Municipality governing the Bloemfontein area. Methodology: The study aimed to determine the impact of drought on citizens’ lives, if and how they adapted to the consequences of drought, and whether the governing body’s planning adequately provides for strategies to prevent/counter the impact of drought. Meteorological data (temperatures and rainfall) and data on dam levels were collected electronically for the years 2016 to 2018 – the period under study. Monthly water use data for that period in time also were collected electronically from the municipality concerned. Multiple-choice questions and close-ended questions were used in a questionnaire survey to gather data on community members’ perceptions, actions, and behaviour during the drought. Quantitative data were analysed statistically, and qualitative data (close-ended questions) were categorised into themes, and which were then quantified for comparisons. Results: The study established that the average annual maximum temperatures of 2016, 2017, and 2018 were 26,4°C, 26,5°C, and 26,4°C were higher than the normal 23°C annual maximum temperatures due to the impact of drought during the study period. The results also showed that the annual rainfall for the years 2016 at 451 mm, 2017 at 500,8 mm, and 2018 at 478 mm was less than the normal annual rainfall of 500-600 mm for the study area, which was indicative of a period of drought. The lack of awareness by the community members could have been one of the reasons why participants did not use more water-saving strategies continually to reduce their water use despite the implementation of the water restrictions. The study finally demonstrates that the Disaster Risk Management Plan of the study area is being implemented continuously as areas that are experiencing disasters including drought are identified and measures such as the implementation of general water restrictions, to ensure continuous water provision, and thus reducing the risk of disaster for the community members Conclusions: The study concluded that the temperatures, rainfall, and dam water levels of the Bloemfontein city have been impacted by drought during the study period. The study also established that the community of Bloemfontein needs to use more strategies to use water sparingly during the drought periods. The study has lastly shown that the implementation of the Disaster Risk Management Plan in Bloemfontein has been put in place and it is effective
A framework for implementing positive learner discipline at selected public secondary schools in the Mpumalanga province
Get PDFThesis (Doctor:Education: (Educational Psychology))--Central University of TechnologyLearner indiscipline has emerged as a global cause for concern for educators and parents in the 21st century. A learning environment marred by noise, disorder, disruption and violence is a breeding ground for low academic achievement. This study sought to establish factors leading to the ineffectiveness of the positive learner discipline (or ‘positive discipline’ – PD) approach and further develop an Afrocentric framework for the successful implementation of PD. The study sought to provide answers revolving around the contributing factors towards learner indiscipline, the effects of indiscipline on teaching and learning, educators’ perceptions on PD, factors leading to the ineffective implementation of PD and the constituents of an effective framework for implementing PD. The study adopted a qualitative approach. Convenience and purposive sampling were used to identify districts and participants. Data were gathered through the use of semistructured interviews and document analysis. Six schools in two districts of the Mpumalanga Province were selected for data collection purposes. Twenty four participants comprising of six principals, six class teachers, six Life Orientation teachers and six chairpersons of School Governing Bodies formed the study sample. Document analysis paid attention to incidents record books, school codes of conduct, as well as minutes for a school disciplinary committee and school safety committee. Data were analysed and presented through thematic content analysis. The findings and literature revealed that family setting, community setting, human rights, peer pressure, the educator, and the learner are the contributing factors behind learner indiscipline. It was further revealed that learner indiscipline has negative effects on teaching and learning. It disrupts learning, instils fear in educators and other learners and slows down learning progress. Educators have no adequate understanding of PD. Participants expressed both positive and negative perceptions of positive discipline. Lack of stakeholder engagement, absence of training, overemphasis on learners’ rights and conditioning of educators and parents on corporal punishment are the factors that have led to the ineffective implementation of PD. A framework for effective implementation of PD should sequentially adopt a multistakeholder approach to engagement where wide consultation is done. Views gathered from all stakeholders should be captured in reviewing policies on learner discipline, and infusing Ubuntu values in repackaging the PD toolkit to suit the local context. Training of stakeholders should follow before implementation at home and school. The study proposed an Afrocentric framework for the implementation of PD at selected public secondary schools in Mpumalanga
The use of essential oils to control pathogen-carrying cockroaches found in Mangaung food markets
No full textThesis (Master: Health Sciences: Environmental Health)--Central University of Technolog
Evaluating The Relationship Between Integrated Reporting And Financial Indicators In Jse-Listed Companies
Get PDFJournal ArticleThe paper explores the relationships between a comprehensive list of financial indicators and the
quality of Integrated Reporting disclosed in companies listed on the Johannesburg Stock Exchange.
These relationships were investigated using the Ernst & Young (EY) Integrated Reports Awards and
financial information obtained from IRESS Ltd for a selection of 45 companies over four years (2014
to 2017), and using Spearman rank-order correlations, a Breusch Pagan test, and five multiple
regression analyses. The results indicate a similar trend in the direction of relationships between the
baseline and other models, except for price-earnings and net profit margin. Statistically significant
positive relationships were identified between Integrated Report Quality (IRQ) and average debtors
collection (DEBT), earnings before interest, taxes, depreciation and amortisation (EBIDTA) and return
on equity (ROE). Statistically significant negative relationships were identified between IRQ and fixedassets
turnover (FATURN), inventory turnover (INV), earnings before interest and taxes (EBIT)
dividend yield (DIVYIELD), dividend cover (DIVCOV) and return on capital employed (ROCE). The
results of this study can assist companies in the effective and productive allocation of their capitals,
which in turn will enhance long-term sustainability
Efficient Wireless Power Transfer For Low Power Wide Area Networks
Get PDFDissertationWireless power transfer (WPT) technologies for small devices and low power sensors have
drawn substantial research attention in recent years. Traditional near and far- eld WPT
systems cannot provide e cient-high power transfer while at the same time maintaining
long range power transfer. A possible candidate to overcome these challenges is the
strongly coupled magnetic resonance (SCMR) WPT technique which can transfer power
at higher transmission e ciency in the medium range. Heretofore, the focus has been to
improve the e ciency and range of the SCMR system. On the other hand, the study to
develop optimal coils or loops of the WPT system utilising less computational resources
as well as using co-simulations between less and high intense software has been limited.
More so, the existing WPT systems are complex and bulky in size making it a challenge
to use these technologies for small footprint applications. Therefore, innovative SCMR
systems that are designed to be easy to fabricate and with low losses and of small footprint
will notably improve various technologies in a variety of applications.
The optimal and small footprint SCMR WPT systems are studied in this work. The
analytical models of the Conformal-SCMR (CSCMR) system are presented rst through
design methodology and analysis. The designed CSCMR systems' performance is envisaged
from the identi ed optimal design parameters through this analysis. Furthermore,
the derived optimal parameters are fabricated, analysed and compared in a 3D simulator,
a conventional CSCMR model and a 2-layer self-resonant resonator model. It was
noted that the 2-layer self-resonant model performed better than the conventional model
and this was veri ed by mathematical formulae and equivalent circuit models. The two
models were then optimised using their derived physical parameters. This was done
through a co-simulation. The results showed that the co-simulation increased the simulation
speeds, therefore saving computational resources. In conclusion, the two optimised
model's transmission e ciency was improved by 30% and 4% for the conventional derived
and the 2-layer self-resonant CSCMR-WPT systems. This was achieved while the
footprint of these systems was reduced
Solar tracking evaluation and comparison towards a competitive Solar Challenger race vehicle
Get PDFThesis (Master of Engineering: Electrical Engineering)--Central University of TechnologyObserved global economic growth increases the demand for energy that is currently, especially in South Africa, generated with unsustainable fossil fuels. A substantial energy user is mobility that includes transportation. It seems that future markets are searching for alternative greener energy sources. One of the largest accessible sources of sustainable energy on earth is the sun, with a large drive of sustainable energy supply aiming at solar power. A sustainable mobility option would be solar powered vehicles and the Sasol Solar Challenge is a testing and development platform for this new technology. The South African Sasol Solar Challenge is a biannual competition and claims to be the ultimate test of technology and innovation. Being the ultimate technology test, it sees the development of some of the world’s most innovative energy technologies. Solar challenger vehicles are prototypical, fully electric vehicles, developed by research and competitive teams. The technology developed by these teams, similar to Formula 1 (F1) racing, might be seen in some form or another in electric vehicles of tomorrow. Events like the Sasol Solar Challenge accelerate research into more efficient solar cells, solar panels (also known as solar modules or PV modules), batteries, semi-autonomous vehicle technology, and battery management and protection systems. This study evaluates and compares solar tracking options towards a competitive solar challenger vehicle. It evaluates a proposal of a transparent aerodynamic cover under which tracking solar panels (also known as PV modules) could move freely, without influencing the aerodynamic characteristic and drag coefficient of the vehicle. This includes test methods, test instrumentation and final evaluation for an optimal cover material. Results indicate the gains with solar tracking and losses of irradiation of cover material with tracking that needs to be considered for drag coefficient gains towards a competitive solar challenger race vehicle. The study started by evaluating special cover materials, i.e. considering their chemical and physical properties. Then demonstrating the design, construction and testing of a scale-model instrument with which to evaluate and compare solar tracking, with and without such covering material. Thereafter it demonstrates the evaluation and comparison of solar tracking of the full-scale 2018 solar power challenger vehicle. The results of small-scale experimentation led to alterations on the full-size solar vehicle design, which included bypass diode placements. The preselection of materials, the design of scale testing instrumentation and scale results compared to the full-scale results are discussed to indicate the gains and losses that occur for a proposed cover. The scale model saw a 7% – 11% energy loss with the presence of the cover. On the full-size model this increased drastically to 20% – 33%. This large difference could be a result of the intense heat generated in the full-size model, as well as the environmental damage (scratches, sunburn) on the clear polycarbonate cover at the time of testing. Measurements were taken in all four cardinal directions. Finding of the research study has showed an increase in power with tracking, but that the energy loss of the cover does not justify decreasing of drag coefficient, when traveling at low speeds. Using real-world measured power, one should, however, reconsider this loss in the drag coefficients of new designs and/or the physical protection of cover material or other factors, like aerodynamic stability and drag at higher speeds
Developing an integrated predictive- explanatory model of behavioural intentions for mobile cellular services
Get PDFThesis (Doctor (PhD) Management Sciences Business Management)--Central University of TechnologyCreating a critical mass of loyal customers and their retention has been recognised as the cornerstone for the future survival of an organisation. However, customer retention strategies depend on the accurate prediction of behavioural intentions (BIs), which is an immediate predictor of actual behaviour. To improve the prediction of BIs, organisations need to understand all the possible factors that can affect a buyer‟s relationship with a brand. Perceived justice (PJSR), service recovery satisfaction (RSat), service quality (SQ), overall satisfaction (OCS), and switching barriers (SBs), have been considered as determinants of BIs in simple bivariate explanatory models. However, we live in a complex multivariate world such that, studying the determinants of BIs in isolation would seem artificial and inconsequential. Furthermore, the previous BIs models have been largely explanatory, which provide little practical relevance without assessing their predictive capacity. Consequently, there has been a call for the development of comprehensive models of BIs that incorporate more variables in a single model, which is both explanatory and predictive. Despite this call, an integrated explanatory-predictive framework that explains how BI antecedents‟ nomological causal relationships collectively lead to the formation of BIs in a consumer's mind is yet to emerge. To address this gap in the research, the researcher synthesised literature from different research streams to construct an integrated explanatory-predictive framework of BIs in situations where service failure and service recovery are involved. Cross-sectional survey data from 405 mobile phone subscribers, collected using a self-administered questionnaire in different districts of Lesotho was analysed using SmartPLS 3.2.9. The model had a high explanatory power (R2 = 0.75), high insample predictive relevance (Q2 value for BI = 0.547) and high out-of-sample predictive capacity [(low positive values of the linear regression model (LM) - the root mean square error (RMSE)]. The mediation tests show that OCS is the central construct through which all the other variables influence the formation of BI. The moderation test of SBs was only significant on the SQ->BI relationship, specifically revealing that when SBs are low, the influence of SQ on BIs is strong, but high SBs tend to obscure the effects of SQ on BI. The importance-performance matrix analysis (IPMA) reveal that OCS was the most important construct, followed by perceived justice (PJSR), RSat and SQ, in descending order. Overall, the results reveal that the performance of the cellular industry on these constructs is above average (50%), but more effort is required to improve their performance. The IPMA results of the indicator items reveal that the reliability dimension of SQ was considered the most important item in determining BI, but in general, the performance of all the indicator items was slightly above the average (50 per cent) mark. Theoretically, the study expands the current knowledge and understanding of the formation of behavioural intentions. Conceptually, the study is unique in that to the researcher‟s knowledge, it is the first of its kind to construct a framework that combines an analysis of the explanatory power, predictive relevance, the importance and performance of the determinants of BI in a single framework. In that regard, the study is a respond to the call for the development of consumer behaviour models that have more practical relevance but being grounded in strong theoretical explanations. Besides its relevance in predicting the future intentions of subscribers in the mobile phone industry, the model also offers specific, actionable recommendations for that guide management when developing customer retention strategies. A detailed explanation of the contribution of this study is discussed in Chapter 8 of this thesis
Assessing Immigrant Entrepreneurs’ Contribution To Employment Creation And Entrepreneurship Development: Case Study Of Small Retailers In Mangaung
Get PDFDissertationIn spite of the numerous initiatives put in place by the South African government to equip its citizens with necessary entrepreneurial skills to create businesses for employment and economic development, the country still faces the shortage of entrepreneurial skills and huge unemployment. In addition to the initiatives, the presence of immigrant resulted in ‘immigrant entrepreneurs’ who are establishing small businesses in various sectors and employing local citizens. However, to my knowledge, no academic research exists that has empirically examined the contribution of immigrant entrepreneurs to local citizens’ employment and entrepreneurial development. This study, therefore, examines the contribution of immigrant entrepreneurs to employment creation and entrepreneurship development of local citizens in the Mangaung Metropolitan area, Free State Province in South Africa.
Drawing on an interpretivist epistemology and qualitative research approach, an interview guide for immigrant entrepreneurs and local citizens was used to establish the contribution of immigrant entrepreneurs on job creation and entrepreneurial development of local citizens. Ten (10) semi-structured interviews were conducted with local citizens and ten (10) interviews were conducted with immigrant entrepreneurs - that added up to twenty (20) participants. Although local citizens expressed some negative opinions about the immigrants, they had positive affirmations of the immigrants’ businesses, which they perceived to boost their business knowledge and standard of living. Immigrant entrepreneurs conceived government support as a valuable tool when seeking to understand their contribution to job creation and to develop the local citizens’ entrepreneurial skills. As such, the results demonstrated that entrepreneurial skills transfer via in-store training influenced local citizens’ decision to start businesses. Moreover, interventions through several initiatives to promote collaborations with immigrant entrepreneurs might help to improve the growth of entrepreneurial development in order to expand the transfer of entrepreneurial skills amongst the local citizens. Lastly, results demonstrated that skills can be transferred to local citizens who are willing to start a business through the intervention of government programmes, and develop effective strategies for fostering long-term bonds between immigrants and local citizens. Details of the study including findings, conclusions and recommendations are presented and discussed in the main report