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The effects of boat mooring systems on squid egg beds during squid fishing
No full textThesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2017.In South Africa, squid fishing vessels need to find and then anchor above benthic squid egg beds to effect viable catches. However, waves acting on the vessel produce a dynamic response on the anchor line. These oscillatory motions produce impact forces of the chain striking the seabed. It is hypothesised that this causes damage to the squid egg bed beneath the vessels. Different mooring systems may cause more or less damage and this is what is investigated in this research. The effect of vessel mooring lines impact on the seabed during squid fishing is investigated using a specialised hydrodynamic tool commercial package ANSYS AQWA models.
This study analysed the single-point versus the two-point mooring system’s impact on the seabed. The ANSYS AQWA models were developed for both mooring systems under the influence of the wave and current loads using the 14 and 22 m vessels anchored with various chain sizes. The effect of various wave conditions was investigated as well as the analysis of three mooring line configurations.
The mooring chain contact pressure on the seabed is investigated beyond what is output from ANSYS AQWA using ABAQUS finite element analysis. The real-world velocity of the mooring chain underwater was obtained using video analysis. The ABAQUS model was built by varying chain sizes at different impact velocities. The impact pressure and force due to this velocity was related to mooring line impact velocity on the seabed in ANSYS AQWA.
Results show the maximum impact pressure of 191 MPa when the 20 mm diameter chain impacts the seabed at the velocity of 8 m/s from video analysis. It was found that the mooring chain impact pressure on the seabed increased with an increase in the velocity of impact and chain size.
The ANSYS AQWA impact pressure on the seabed was found to be 170.86 MPa at the impact velocity of 6.4 m/s. The two-point mooring system was found to double the seabed mooring chain contact length compared to the single-point mooring system. Both mooring systems showed that the 14 m vessel mooring line causes the least seabed footprint compared to the 22 m vessel
The media impact of the 2014 FIFA World CUP in selected key marketsτм
No full textThesis (MTech (Tourism and Hospitality Management))--Cape Peninsula University of Technology, 2017.The hosting of 2014 FIFA World CupTM was an ideal opportunity for Brazil to enhance its international image. The aim of this study is to investigate the impact on Brazil and on Rio de Janeiro (as a host city and major tourist destination) of mainstream media reporting on the hosting of the 2014 FIFA World CupTM. It provides a picture of how Brazil and Rio de Janeiro were reported in selected newspapers at different stages of the event: pre-, lead-up, during, and post- the 2014 World Cup. The study also seeks to ascertain whether the major objectives of the Brazil World Cup bid were met in the hosting of this mega-event. A media content analysis was conducted in four key tourism markets: Argentina, USA, Germany and Portugal. These countries were chosen because they represent Brazil’s main tourism markets and reported significant numbers of ticket sales for the event. The methodology used was qualitative analysis, including content sourcing, content identification and the use of Leximancer, an analytic tool for large amounts of textual data. The study examined online newspapers with the largest readership and circulation numbers in the selected markets. In total, 1961 online newspaper articles relevant to Brazil’s hosting of the 2014 FIFA World CupTM were analysed.
The findings revealed both positive and negative sentiments associated with Brazil’s hosting of the event. A key finding from the analysis was that for all markets, there was a shift from relatively positive sentiment in the pre-World Cup period, to more negative sentiment in the lead-up, followed by a return to positive sentiment during and after the World Cup. Having shifted to a more negative view leading up to and during the event, the USA market was dominated by media attention to social unrest and corruption. The period immediately prior to the tournament recorded an increase in both positive and negative media coverage in the US, German and Portuguese markets, but became more positive in the Argentinian market. Thus, the lead-up period was particularly significant in all markets. Safety and security concerns expressed in the lead-up period decreased significantly during the hosting and post- periods, and a positive image of the country was noticeable in the international media. Therefore, while the positive sentiments emerging during the event should be capitalised on, Brazil should also address the lurking concerns and negative perceptions that continue despite its successful hosting of the mega-event. By doing this the nation can consolidate its brand’s position in a sustained and positive way. As different reporting tones were noticed in the different markets across the time periods, it becomes important to consider these changes in the future event marketing and positioning of Rio de Janeiro as the leading tourism destination and events capital for Brazil, especially in relation to Rio de Janeiro’s hosting of future events
Seasonal variability and the relationship between dissolved inorganic nutrients and selected environmental parameters inshore and offshore of St. Helena Bay
No full textThesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2017.The purpose of the present study was to apply data collected monthly over a 6-year period along the almost 200 km long St. Helena Bay Monitoring Line in the Southern Benguela upwelling system to investigate co-variation between an upwelling index calculated from nearby wind records and physical and chemical properties along the transect. The extent to which the well-documented seasonal upwelling cycles is manifested at the surface along an inshore-offshore variation was investigated in the context of implications for the validity of remote sensing as a monitoring tool in this ocean area and to improve understanding of the physical drivers of biological processes in St. Helena Bay. This study shows that surface temperature and nutrient concentrations exhibit very poor seasonality and weak correlation with the upwelling index. This is, despite clear evidence for spatial inshore-offshore gradients in temperature, nutrients, and chlorophyll-a, consistent with an upwelling regime. The upper ocean temperature gradient shows a much better correspondence to the upwelling index but at the same time demonstrates that surface heating, and not vertical mixing related to upwelling, controls the upper ocean temperature gradient.
In this study linear lagged correlations were also examined and discussed to gain insight into the effect upwelling has on the surface waters in St. Helena Bay with the view of determining the following: (1) Does upwelling lead to an increase or decrease of the water properties? (2) What is the characteristic lag between an upwelling event and its effect on these water properties? (3) Is the effect and/or lag different for the different seasons? and (4) Is the effect and/or lag different for stations inside the bay and those outside the bay?. A combination of surface turbulent cooling through upwelling occurred after a lag of 8 to 10 days in winter and early summer, but less than half in late summer, similar to results obtained with salinity. However, the rest of the salinity results fit in poorly with the temperature results. The only significant correlation obtained with the inshore stations during late summer is the inexplicable positive correlation at a lag of 7 days. For all three seasons virtually none of the oxygen results fit the expected pattern. All three nutrients showed a more positive correlation coefficient and significance than the negative ones. Significant negative correlations occurred mainly during late summer at lags of 7 to 9 days caused by planktonic depletion of nutrients. Also, in this season, significant positive correlations between south-north wind and nutrients only occurred at short lags. This observation supports the earlier temperature-based conclusion that the influence of upwelling develops most rapidly at this time of the year. A rapid increase in chlorophyll-a levels followed by nutrient enrichment of the surface layers are evident.
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The results suggest that remote sensing techniques would be inadequate tools to monitor upwelling events in the Southern Benguela. Secondly, the incidence of phytoplankton blooms is more likely triggered by stratified conditions associated with surface heating than relaxation of upwelling winds. Finally, these results also emphasise the importance of validating lagged outputs against real-time measurements in supporting a simpler hydrological model in narrowing down these significant uncertainties
Design and manufacturing of a temperature controlled chamber for a tensile testing machine
No full textThesis (MTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2017.Material testing is an important test to researchers in material science fields and other engineering related fields. This is the base for material evaluation prior to the application. This test is used in the engineering field to determine the strength of materials which is an aspect of assigning materials to different functions. The uniaxial tensile testing of material is the most common form of testing the strength of metallic material - usually to investigate whether or not the material is worthy of the intended application.
Material testing is normally performed under uncontrolled conditions in most laboratories. Numerous attempts had been previously made in attempt to control the temperature conditions when performing the tensile test on special materials such as shape memory alloys (SMA) and other smart materials. Various methods had been employed to control the temperature during tensile testing, methods such as induction heating, warm liquid baths, etc.
The aim of this study was to develop a temperature controlled environment for the Houndsfield tensile testing machine which is found at the Cape Peninsula University of Technology in the Mechanical Engineering Department workshop. This was achieved through designing and manufacturing of a thermally controlled chamber -better known as a furnace. This chamber was tested for the optimal combination of proportional, integral and derivative parameters which were tuned on the proportional integral derivative (PID) controller. Performing the tensile test under controlled thermal conditions will allow the analysis of SMAs and other materials behaviour at different temperatures. With the aid of the manufactured chamber, the superior features of the SMA will be able to be studied. The manufactured thermal chamber which is electrically powered is insulated with a special ceramic refractory material to prevent the heat from escaping the chamber. The PID controller was used to control the temperature and heating elements act as the heat source. The manufactured chamber could withstand the maximum temperature 350oC that it was initially designed for. However, the challenge of having the specimen to be tested fully inside the chamber was overcame by designing specimen connectors that connected the specimen to the tensile testing machine. Tensile tests were conducted on the SMA wire at room temperature and other various controlled temperatures and different behaviours were observed on the stress-strain graphs
Development of methods for modelling, parameter and state estimation for nonlinear processes
No full textThesis (DTech (Electrical Engineering))--Cape Peninsula University of Technology, 2018.Industrial processes tend to have very complex mathematical models that in
most instances result in very model specific optimal estimation and designs of
control strategies. Such models have many composition components, energy
compartments and energy inventories that result in many process variables that
are intertwined and too complex to separate from one another. Most of the
derived mathematical process models, based on the application of first principles,
are nonlinear and incorporate unknown parameters and unmeasurable states.
This fact results in difficulties in design and implementation of controllers for a
majority of industrial processes. There is a need for the existing parameter and
state estimation methods to be further developed and for new methods to be
developed in order to simplify the process of parameters or states calculation and
be applicable for real-time implementation of various controllers for nonlinear
systems.
The thesis describes the research work done on developing new parameter and
state estimation methods and algorithms for bilinear and nonlinear processes.
Continuous countercurrent ion exchange (CCIX) process for desalination of
water is considered as a case study of a process that can be modelled as a
bilinear system with affine parameters or as purely nonlinear system. Many
models of industrial processes can be presented in such a way. The ion
exchange process model is developed based on the mass balance principle as a
state space bilinear model according to the state and control variables.
The developed model is restructured according to its parameters in order to
formulate two types of parameter estimation problem – with process models
linear and nonlinear according to the parameters. The two models developed are
a bilinear model with affine and a nonlinear according to the parameters model.
Four different methods are proposed for the first case: gradient-based
optimization method that uses the process output measurements, optimization
gradient based method that uses the full state vector measurements, direct
solution using the state vector measurements, and Lagrange’s optimization
technique. Two methods are proposed for the second case: direct solution of the
model equation using MATLAB software and Lagrange’s optimisation
techniques.National Research Foundation (NRF
Oxidative stress responses in the aquatic macrophyte, Ceratophyllum Demersum L., as biomarkers of metal exposure
No full textThesis (DTech (Environmental Health))--Cape Peninsula University of Technology, 2017.Metal pollution in aquatic environments is considered a major environmental concern because of variation in several abiotic factors that impose severe restrictions on organisms living in these areas. Ceratophyllum demersum L. (family Ceratophyllaceae), a hornwort or coontail, free floating rootless macrophyte has been suggested a suitable model for investigating metal stress and was used in the current study. This study assessed the use of selected biological responses, namely antioxidant responses and changes in chlorophyll concentration in Ceratophyllum demersum L., as biomarkers of metal exposure, and also investigated the field application of these responses in the Diep River. The ultimate aim was also to determine the usefulness of C. demersum as model of metal contamination and as phytoremediator after a pollution event. An investigation of metal bioaccumulation in this macrophyte exposed to different concentrations of a combination of metals over a five-week exposure period in a greenhouse, was undertaken, as well as a field study in the Diep River, Milnerton, Cape Town and a pond (reference site) at the Cape Peninsula University of Technology, Cape Town, to validate experimental results. In the laboratory study the water was contaminated once off at the beginning of the study, to simulate a pollution event. The metal concentrations in the water and plants were measured in the four treatments and the control every week over a five-week exposure period. The samples were acid-digested and analysed with an Inductively-Coupled Plasma-Mass Spectrophotometer (ICP-MS). The results showed that concentrations of the metals in the water varied in all treatments over time with no specific patterns amongst the treatment groups. This macrophyte proved highly effective in the bioaccumulation of these metals at all four exposure concentrations. The metals bioaccumulated rapidly in the plants after the water was spiked.
The main focus of the study was to investigate the possible use of biochemical responses in C. demersum as possible biomarkers for metal exposure. A range of antioxidant/oxidative stress parameters were measured in the plant exposed to a combination of metals (Al, Cu, Fe, Zn) in four different treatments over the five week exposure period. Total antioxidant capacity (TAC) was measured using Total Polyphenols (TP), Ferric Reducing Antioxidant Power (FRAP) and Oxygen Radical Absorbance Capacity assay (ORAC), enzyme activity was determined using Catalase (CAT), Superoxide Dismutase (SOD), Ascorbate Acid (AsA) and Total Glutathione (GSHt) and lipid peroxidation was measured by using Thiobarbituric Acid Reactive Substances (TBARS) and Conjugated Dienes (CDs). The cocktail of the four metals induced significant changes in the antioxidant defence system of C. demersum, including the antioxidant enzyme activities. The different metal exposures disturbed the cellular redox status in the plant. The current study has demonstrated that this macrophyte shows tolerance to metal-induced oxidative stress and that it can survive under relatively high concentrations of these metals by adapting its antioxidant defence strategies.
Chlorophyll was extracted in 80% chilled acetone in the dark and the absorbance values were determined using a spectrophotometer. Chlorophyll a (chl a), chlorophyll b (chl b) and total chlorophyll (chl t) contents were measured under different exposure concentrations of metals in the macrophyte. The results of this study indicated that chlorophyll contents were variable over the exposure period and no significant differences in chlorophyll concentrations were found between weeks.
A field study in the Diep River and the pond located at the CPUT campus (reference site) was conducted to validate experimental results. Plants in a polluted section of the Diep River were shown to bioaccumulate metals to high concentrations. Bioaccumulation of metals in C. demersum might have induced oxidative stress, and other environmental factors such as temperature- and chemical stress might have caused chlorophyll degradation. The chlorophyll concentrations in the plants of the pond (reference site) might also have been affected by temperature and chemical stress of the water. Significantly higher AsA, CAT, ORAC, SOD and TBARS concentrations in the Diep River plants might be an indication that the plants in the river might be well adapted to the constant exposure to metals and that the plants might have developed a tolerance mechanism to cope with oxidative stress compared to those of the pond. The results show that metals are bioaccumulated quickly by C. demersum after the water is contaminated with metals, i.e. after the "pollution event". However, over time, metals are continuously exchanged between the plants and the water, accounting for the fluctuations in metal concentrations observed over time.
This study has shown that C. demersum has phytoremediation potential because it was able to remove high concentrations of metals from the contaminated water. Therefore, C. demersum, can be applied as a model for metal contamination and a phytoremediator after a pollution event. The potential to antioxidant responses and chlorophyll content as biomarkers of metal exposure in C. demersum have been demonstrated
Factors influencing effectiveness of change management interventions in a selected petrochemical company in the Western Cape, South Africa
No full textThesis (MTech (Business Administration))--Cape Peninsula University of Technology, 2017.Change in today‟s business situation may be seen as unavoidable; however, the absence of standard change interventions within an organisation can cause an impact on the functioning of the business and its survival in the long run. Thus, it is ideal for the South African petrochemical industry to find a suitable intervention for change models that will assist them in navigating its effectiveness. This study has used an investigative approach to understand the effectiveness of interventions of change management in petrochemical organisations in the Western Cape, South Africa.
A qualitative case study was used in this research, as data was collected directly from interviews by fieldworkers, while written documents were also consulted. It was found that a number of factors influence effective change management in the SA petrochemical industry. Some of the factors that were elicited for this study include: organisational structure and size and administrative methods; the introduction of new technology; processing and communication; changes in employee demographics; government regulations; and economic competition. Furthermore, the study also provides a framework that can be used to guide and assess effective changes within the SA petrochemical industry
Forward osmosis membranes for direct fertigation within the South African wine industry
No full textThesis (MTech (Chemical Engineering))--Cape Peninsula University of Technology, 2017.Water scarcity in South Africa (SA) and more specifically Cape Town, Western Cape, has escalated to disaster levels in 2018. Agriculture and irrigation account for 62% of SA’s accessible potable water (Thopil & Pouris, 2016), and although the agriculture sector plays a pivotal role in SA’s socio-economic development, the future of the sector is dependent on critical issues such as climate variability and population growth (Besada & Werner, 2015). Wine production in SA is an important agricultural activity, contributing great economic value to the agri-food sector. However, despite this, the wine industry is responsible for vast water consumption and the unsafe disposal of winery wastewater, which are critical issues from an environmental and economic standpoint.
The ever-imminent crisis pertaining to the limited supply of fresh water from conventional water resources has necessitated the need to develop alternative water resources to supplement an increased water supply, which include the reuse of wastewater, ground water, brackish water (BW) and seawater (SW) desalination. When fresh water supplies are limited, agricultural irrigation is penalised. The reuse of agricultural wastewater as a substitution for potable water irrigation may prove beneficial in areas where water shortages are severe.
Forward osmosis (FO) is a developing desalination technology that has received increased attention as a promising lower-energy desalination technology. FO technology relies on the natural osmotic process, driven by a concentration gradient as opposed to significant hydraulic pressures like reverse osmosis (RO). Water is extracted from a lower concentrated feed solution (FS) to a highly concentrated draw solution (DS). The term “lower energy” is only applicable for applications where the recovery of the DS is not required. FO technology offers several advantages. However, the lack of suitable membrane modules and DSs hinder its practical application. FO offers novelty applications in which specialised DSs are selected to serve as the final product water, most notably concentrated fertilisers for direct fertigation.
The aim of this study was to evaluate the performance and compatibility of commercially available cellulose triacetate (CTA) and aquaporin biomimetic FO membranes with commonly used fertilisers for direct fertigation within the SA wine industry, using a fertiliser drawn forward osmosis (FDFO) system
Postgraduate student success rate with free-form information searching
No full textThesis (MTech (Business Information Systems)--Cape Peninsula University of Technology, 2017.The Internet has become a useful instrument in connecting users, regardless of their
geographical locations, and has thus has made the world a small village where users can
interact and search for information. Another aspect that has made the Internet popular
amongst users, is its growing popularity as a global resource connecting millions of users
surfing the Web daily, searching for and sharing information. A successful search for
information depends on the user’s ability to search effectively, and this ability is based on
computer competency, knowledge of Information Technology (IT), perceptions of IT usage,
and the demographics of the user. These user’s characteristics tend to influence the overall
user experience. Although the Internet is used by different groups of users to achieve
different objectives of information search, not all of them achieve these objectives.
The main aim of this study was to determine the success rate of post-graduate students
using free-form information searching to find academic reference materials
The influence of learning support on foundation phase learners’ self-esteem
No full textThesis (MEd (Inclusive Education))--Cape Peninsula University of Technology, 2017.A need for learning support in mainstream schools has come to the fore with the
implementation of the inclusive education policy in South Africa. Learners who
experience barriers to learning are withdrawn from the mainstream class in small
groups in order to receive extra support in their home language and mathematics.
The purpose of this mixed-method convergent study was to determine the influence
of withdrawal from the mainstream classroom, for learning support, on the foundation
phase learners’ self-esteem. The phenomena were studied from the perspective of
mainstream and learning support teachers as well as the learners. In the quantitative
phase, surveys consisting of open and closed questions were distributed to seventy
mainstream and seven learning support teachers. The qualitative phase used
Interpretative Phenomenological Analysis (IPA) to analyse data gleaned from the
Rosenberg Self-Esteem Scale which had been adapted into an interview schedule in
order to determine the perceptions of self-esteem, of five foundation phase learners,
who were withdrawn from the mainstream classroom for learning support.
This study found that learning support did not seem to have a negative influence on
the global self-esteem of the learner participants in this study. It was found that the
school culture and mainstream teachers’ attitudes had a negative influence on
learners’ self-esteem. Other variables that had a negative influence on self-esteem
were family relationships and the learners’ social competence and acceptance, and
non-academic competencies were shown to have a greater effect on self-esteem.
Overall, both the teachers and learners indicated that they perceived that LS had a
positive influence on learners’ self-esteem