Central University of Technology
Central University Of Technology Free State - LibraryCUT, South AfricaNot a member yet
2545 research outputs found
Sort by
Optimal Management Of A Small Grid Connected Pv With Groundwater Pump Hydro Energy Storage For Farming In Arid Areas
Get PDFRunning a farm that solely depends on grid electricity, is not easy-going, considering the current state of electrical energy in our country (South Africa). Therefore, onsite electricity generation is achieved by using off-grid approaches, such as wind, diesel generator, conventional small hydro system and solar. However, due to high cost of diesel fuel, unavailability of continuous energy from the sun and wind, these energy generation methods may require extra energy storage systems in order to be considered as a reliable solution for onsite electricity generation for farming environment. Further combination and incorporation with various affordable energy generating sources, is a necessity in improving the grid’s economical management. This study used solar PV, incorporated with an underground pumped hydro storage (UPHS) system, whilst a borehole is used as a lower reservoir.
An off-grid UPHS is a promising technology that may be used in any farming environment that has sufficient underground water. This technology is currently under development and lacks implementation.
The purpose of this study was to investigate the possibilities of controlling and optimising the daily operation of the proposed grid-connected renewable energy system, by maximising the usage of the renewable resources, whilst minimising the use of grid electricity to supply the load demand of a farm, without any load supply shortage. The design and sizing of the proposed system was performed, using a Hybrid Optimization Model for Electric Renewable (HOMER). The model formulation, effectiveness and economic analysis was performed and simulated, using linear programming with MATLAB software. Therefore, the simulation results reveal that using the developed model to optimally manage power generated by PV and the PHS, the cost of the electricity for farm operation may be reduced. Nonetheless, the study also raises awareness to the use of renewable energy in conjunction with grid electricity under TOU tariff rates. As well as water conservation and food production to boost our current economic status
Artificial Reconfigurable Wireless Network Optimization Based On Battery Levels
Get PDFA Wireless Sensor Networks (WSN) was developed, along with a testbed that
could evaluate the system under scrutiny on energy consumption parameters. The
development of an artificial reconfigurable wireless network optimization routing
protocol based on battery levels was created in a lab environment where certain variables
were controllable. This study focused on measuring energy of a network based on
different routing protocols. To capture data, physical batteries were replaced with a
power source that was developed to capture the energy usage of each node in the system
simultaneously.
The development of a system that could test the energy consumed by a WSN was
one part of the study, whilst the important part was to be able to analyse energy
consumed by a network as a whole.
Analysing a WSN by capturing data based on routing topology formed a
conclusion based on data that was captured in the lab. Different packet sizes, TX power
levels and routing protocols were tested in this dissertation on a custom developed
testbed. Results did show a predictable outcome clearly indicating different energy
consumptions per topology
Numeracy Students’ Perspectives On A New Digital Learning Tool At A South African University
Get PDFPublished ArticleStudents thrive in learning environments where they are able to remain engaged, interested and motivated. A new digital learning tool, MindTap Math Foundations, claims to transform learning by bringing elements from the interactive, gamified world so that students stay engaged, persist through challenges, feel more supported and connected with instructors, other students and their own learning experience. A South African university was the first higher education institution in South Africa to make use of this personalised learning system. A survey was employed to assess the effectiveness of MindTap Math Foundations as a digital learning tool. The focus of the article is on the analysis of the open-ended questions in the survey. The findings of this research support the claims Cengage make regarding the platform’s benefits. Participants’ responses revealed that the new digital learning tool is generally perceived as positive and beneficial for learning numeracy. Students’ feedback also provided ideas and proposals for potential enhancement. Through students’ experiences shared it was possible to pinpoint the strengths and challenges regarding aspects needing consideration and improvement
Incorporating Social Sustainability Dimensions into Infrastructure Delivery Systems: A Qualitative Analysis of Stakeholders’ Perspectives
Get PDFPublished ArticleThis study explored the benefits of incorporating social sustainability into the delivery of infrastructure projects within
South Africa. The perspective is from that of the stakeholders, As a phenomenological study, it relied on semistructured
interviews for gathering data. Post-interview transcripts were analyzed thematically, and pre-set themes
were utilized to ensure construct validity, a critical component for enabling credibility in qualitative research. Findings
revealed the efficacy of social sustainability to enable the successful delivery of projects when mainstreamed into the
delivery process. However, stakeholders highlighted the costly and time-consuming nature of the consultation processes—
an integral part of social sustainability—as a shortcoming. This exploratory study contributes to the development
of a common definition for social sustainability within South Africa’s infrastructure delivery system. Further studies
will attempt to attain statistical generalization of its findings using questionnaire surveys for a more representative
sample. It is expected that these findings will be able to contribute to the growing discourse on the phenomenon in
developing countries where there is increasing advocacy for using project delivery to combat social inequality. This
study’s novelty stems from its bid to explore the benefits accruable from the integration of social sustainability into
infrastructure delivery processes
Additive Manufacturing of Devices Used for Collection and Application of Cereal Rust Urediniospores
Get PDFPublished ArticleOptimized inoculation procedures are an important consideration in achieving
repeatable plant infection when working with biotrophic rust fungi. Several plant
pathology laboratories specializing in rust research employ a system where the collection
and application of fungal spores are accomplished using an exchangeable gelatin
capsule. Urediniospores are collected from erumpent pustules on plant surfaces into
a capsule fitted to a cyclone collector controlled by a vacuum pump. By adding light
mineral oil to the same capsule, the spore suspension is then sprayed onto plants
by means of a dedicated atomizer (inoculator) connected to an air pressure source.
Although devices are not commercially available, modern day technologies provide an
opportunity to efficiently design and manufacture collectors and inoculators. Using a
process called Additive Manufacturing (AM), also known as “3D printing,” the bodies
of a collector and inoculator were digitally designed and then laser-sintered in nylon.
Depending on availability, copper or aluminum tubes were fitted to the bodies of both
devices afterward to either facilitate directed collection of spores from rust pustules on
plant surfaces or act as a siphon tube to deliver the spore suspension contained in
the capsule. No statistical differences were found between AM and metal inoculators
for spray delivery time or spore deposition per unit area. In replicated collection
and inoculation tests of wheat seedlings with urediniospore bulks or single pustule
collections of Puccinia triticina and P. graminis f. sp. tritici, the causal organisms of leaf
rust and stem rust, consistent and satisfactory infection levels were achieved. Immersing
used devices in acetone for 60 s followed by a 2 h heat treatment at 75 C produced no
contaminant infection in follow-up tests
"I Hate Tuesdays!" The Self-Efficacy Beliefs of Postgraduate Language Practice Students
Get PDFPublished ArticleThe high drop-out and low throughput rates in higher education institutions is a matter of concern. Students must overcome many psychological barriers in the pursuit of an under- and postgraduate qualification. Self-efficacy is regarded as an under-researched psychological variable that may influence students’ success in higher education institutions. Drawing on Bandura’s Social Cognitive Theory, this study explores the self-efficacy beliefs of postgraduate Language Practice students. A qualitative research design was employed. Eleven narrative essays were completed and analysed by means of directive coding. Tuesdays were identified as the worst day of the week due to the module Research Methods and Techniques, that impacted negatively on the students’ self-efficacy beliefs. Social engagement in the form of support groups is seen as an important role player in self-efficacy beliefs. Educators should consider students’ various backgrounds when engaging with students, since this aspect proves to be an important factor in the development of self-efficacy beliefs. The findings may help navigate educators towards rendering the necessary emotional and social student support as a strategy to address the low success rate in universities
Spatio-Temporal Climate Change Risk Assessment: Mangaung Metropolitan Municipality, South Africa
Get PDFPublished ArticleScientists have warned about global warming, resulting in climate change risks such as droughts. In 2015,
the Free State provincial government declared a state of drought risk disaster which was extended into
2016. The current study aimed to (i) assess the climate change risk on annual and seasonal temporal scales
over all areas of the Mangaung Metropolitan Municipality, (ii) determine most-at-risk areas and (iii) advise
government authorities /risk disaster management stakeholders about disaster risk reduction projects aimed
at resilience and capacity building against adverse effects of climate risk disasters. Ten climate change
vulnerability variables were collected from Stats SA, census, 2011. The study applied principal component
analysis to determine the key variables that give rise to the existing vulnerability conditions in the study
area. A 43 year long time series data set (1973- 2016) was also collected from an online source for RDI
computation. The results show that some of the main underlying variables behind high vulnerability in this
municipality are; number of people with no income, the young (0-14) and the elderly (65+), as identified by
principal component analysis. The main towns seem to be less vulnerable compared to the rest of the other
areas under study. The most vulnerable areas are in the outskirts of Thaba Nchu. Furthermore, climatic
hazard analysis using RDI showed constant hazard severity and probability over a 43 year long time series
data set on annual basis. To further assess climate change, RDI was computed on seasonal time scales
which also showed no significant differences in both severity and probability. Due to the fact that the study
used only one station over Mangaung Metropolitan Municipality to assess climate change conditions, the
risk assessment analysis differences were influenced by differences in the vulnerability levels. High risk
levels are therefore in the rural areas. The study recommends that the government and all relevant
stakeholders set up income generating projects through which young people will not necessarily seek jobs
in urban areas and help afford higher education costs
Attitudes of Academics Towards Mandatory Inclusion of Entrepreneurship within Academic Programmes, A South African Case-Study
Get PDFPublished ArticleYouth unemployment, especially among graduates, continues to be widespread nationally and internationally.
Minimal research is reported on the role of academics as change agents to drive and instil entrepreneurial spirit
among students. This article reports on a survey done in South African institutions of higher education about the
attitudes of academics to the inclusion of entrepreneurial programmes as mandatory in an academic setting. The
difficult situation in which university staff find themselves currently, balancing the three roles university
institutions are expecting of them, namely teacher, researcher, community worker, has an impact on their
attitudes to change. With the appropriate didactic approach to entrepreneurship, students’ entrepreneurial
orientation is likely to be enhanced. For this article, a mixed method, i.e. in-depth desktop documentary analysis
and semi-structured questionnaire was used to collect data from 161 purposively sampled respondents. ANOVAs
and post hoc multiple comparison of means tests revealed that gender, education level and age are significant in
shaping the interest lecturers have in entrepreneurial programmes for their students. Demographic data of
respondents differed significantly in terms of their attitudes towards the importance of entrepreneurial orientation
and their abilities to transfer vital entrepreneurial competencies to students. Seventy eight percent of
respondents were in favour of a much stronger presence of entrepreneurial emphasis across academic
programmes, with 52% in support of it being mandatory. Interactive, problem- and project-based, simulations,
and modelling were viewed as the most effective didactical strategies by academics to foster and inculcate
entrepreneurial spirit amongst students. This research may be used not only to inform curriculum development
policies on didactic approaches to be applied to subjects such as entrepreneurship at the universities, but also
help to convert academics into entrepreneurial advocates
A Radiographic Criteria Checklist to Determine Reasons for Errors, Resulting in Sub-Optimal Routine Shoulder Projections
Get PDFPublished ArticleBackground: Optimal shoulder images must adhere to specific radiographic criteria before
they are sent to the radiologist for reporting. Repeat x-rays of the shoulder may increase
radiation exposure to the patient.
Aim: The aims of this study were to determine whether images adhered to the required
radiographic criteria for routine shoulder imaging and to identify possible reasons for
non-adherence.
Setting: The study was conducted at an imaging department at a tertiary academic hospital in
Bloemfontein, South Africa.
Methods: A criteria checklist compiled from literature was used to evaluate 578 routine
shoulder images including anteroposterior (AP) with external rotation and lateral-Y (LAT-Y)
projections. The checklist determined whether the shoulder images adhered to the criteria
with regard to the anatomy included, positioning and technical factors, such as inclusion of the
correct anatomical lead marker. Data were analysed using SAS Version 9.2 statistical software.
Results: More than 80% of the AP external rotation images included unnecessary anatomical
structures owing to incorrect centring. In four out of seven criteria pertaining to positioning for
AP external rotation imaging, at least 70% of images were performed incorrectly. Four-sided
collimation was not present in more than 50% of both AP external rotation and LAT-Y images
because of incorrect centring, while more than 30% of shoulder images presented with
anatomical digital markers.
Conclusion: The application of criteria required for shoulder imaging must be addressed at
the participating imaging department to improve overall patient care. An in-service training
session is recommended to enhance the radiographic technique with regard to routine shoulder
projections
Pigeon Presence on PV Modules ARE Largely Random Events
Get PDFPublished ArticleThe presence of pigeons on PV modules can negatively affect the output power of a solar renewable energy system. The body of the pigeon itself (and especially the tail) may cause short periods of shading of individual cells, leading to the formation of hotspots. Bird excreta left by the pigeon may cause longer periods of shading, leading to an extended reduction in output power. Some type of intervention may be required to repel pigeons from PV modules, in order to try and maintain the overall efficiency and sustainability of a system. The purpose of this paper is to evaluate the reduction in output power of a pico-solar system in order to determine if a possible pattern, or routine, exists with regard to the presence of pigeons. A 10 W pico-solar system was installed in a semi-arid region of South Africa that is home to the feral pigeon (Columba livia). A pigeon detection technique was developed and applied over a period of 13 months to determine when and for how long these pigeons rest on top of a PV module (these are referred to as events). Although these events are primarily random in nature, results do indicate that feral pigeon presence is lowest on a Wednesday during the week and in the summer periods of January to March during a calendar year. They tend to spend, on average, 118 seconds perched on top a PV module, where their tail and droppings cause the most significant impact in terms of interrupting the direct beam radiation from the sun for an individual cell. It is recommended to use these results in formulating an appropriate intervention that may be used as a scare tactic to repel feral pigeons away from PV modules