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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
121

Use of food-buying practices within different socio-economic classes in the city of Cape Town

Harper, Crystal January 2013 (has links)
Thesis submitted in fulfilment of the requirements for the degree Master of Technology Consumer Science: Food and Nutrition in the Faculty of Applied Sciences at the Cape Peninsula University of Technology 2013 / Consumer debt has escalated in South Africa ever since the country sank into a recession in early 2009. One of the many consequences of this economic downturn has been a major increase in energy, transport and food prices. Food-buying strategies can be used by consumers to help to reduce the amount of money, which is spent on food, and increase funds that are available for other household expenses. The main objective of this study was to determine the use of four pre-selected food-buying practices by consumers who reside in different socio-economic status (SES) areas in the City of Cape Town. Residents of lower SES areas have been found to have purchasing patterns that are different to those who live in higher SES areas. The subsidiary objectives were to further establish whether there is a difference in the use of food-buying practices by consumers who reside in different SES areas, and to ascertain whether shopper and demographical characteristics have an influence on the use of food-buying practices among consumers in general as well as among consumers within the same SES area. A consumer intercept survey was conducted after being granted ethics approval. Three groups of respondents that represent a low, middle and high SES area were systematically sampled. A total of 1 200 consumers (95% response rate) who are older than 18 years anonymously and voluntarily participated in the study, which was conducted at pre-selected stores in the suburban areas of Delft (low SES area), Maitland (middle SES area) and Meadowridge (high SES area) in the City of Cape Town. These areas and stores were selected to represent the SES of households or consumers, respectively, based on the demographic and employment profile that was provided for each by Statistics South Africa‟s 2001‟s census profiles. The data was collected by using a pilot tested structured, self-administered questionnaire consisting of mainly multiple-choice questions, which gathered information from the respondents regarding their shopper and demographic characteristics, as well as their frequency of use of the four food-buying practices (represented by six structured questions each) as: (i) use of a shopping list; (ii) use of advertisements to plan shopping; (iii) comparison of prices amongst different brands; and (iv) avoidance of impulse buying. These food-buying practices were selected based on available consumer education literature, which focused on the use of these food-buying practices and a pilot study that was conducted in 2011, which indicated that these four practices were most frequently used by the consumers who were surveyed. Within each SES area most of the Cronbach‟s alpha coefficients that were obtained were >0.9 among the six questions, which represented each food-buying practice, and reflected strong internal consistencies among the questions. The Generalised Linear Model analysis of variance utilising the Wald statistic, which is based on the chi- square distribution and Bonferroni pair-wise comparisons, were used to determine significant differences between respondents‟ use of the food-buying practices and their SES area group, as well as their shopper and demographic characteristics. A significant level of p<0.001, as well as p<0.05 was used. Most (60 to 80%) of the respondents in each SES area are female. Within the total sample, low and middle SES areas a majority (62 to 73%) of the respondents were between 26 to 55 years of age, whereas in the high SES area a majority (63.5%) of the respondents were 46 years and older. In general, more than half (52 to 56%) of the respondents were married and most (38 to 55%) were employed full-time and had household sizes, which mainly (18 to 23%) consist of two to four members. Regarding highest level of education attained, most of the respondents in the total sample either had a Grade 8 to 11 (37.6%) or a Grade 12 (24.7%), whereas most (54%) respondents in the high SES had either acquired a post-matric diploma or certificate, degree or post-graduate degree. Most (67 to 89 %) of the respondents within the total sample, middle and low SES area associated themselves with the Coloured population group, whereas most (56.7%) of the respondents in the high SES area associated themselves with the White population group. Concerning household monthly income, two thirds (65%) of the respondents within the high SES area had an income of R12 801 upward; most (77.5%) of the respondents within the middle SES area had an income of R801 to R12 800 per month; and more than half (57%) of the respondents in the low SES area received an income of R800 to R3 200 per month. In general, most respondents indicated that they shopped for food once a week (33 to 48%); took less than half an hour to shop for food (40 to 52%); and usually shopped alone for food (68.9%). Cash was the most prevalent means of payment among respondents within the total sample (66.7%), middle (70.5%) and low (93%) SES areas, while most (43.2%) respondents in the high SES area paid by means of a debit card. Among the respondents who reside in the different SES suburban areas, differences in the use of food-buying practices were revealed. Respondents within the high (p<0.001) and middle (p<0.05) SES areas displayed a higher propensity to use a shopping list, yet a lower propensity to use advertisements compared to respondents within the low SES area. Respondents within the low and particularly middle SES area displayed a higher propensity to compare prices (p<0.05) compared to respondents within the high SES area. No differences (p>0.05) for the avoidance of impulse buying as a food-buying practice were found among respondents within a low, middle and high SES area. A largely low propensity to avoid impulse buying was found. Regarding shopper characteristics, the respondent payment method influenced the use of a shopping list (p<0.05), use of advertisements (p<0.05 and p<0.001 between the payment methods) and propensity to avoid impulse buying (p<0.05) as food-buying practices within the low SES area. Among respondents, in general, the payment method influenced the avoidance of impulse buying (p<0.05) as a food-buying practice. The length of time that it took to shop influenced the use of a shopping list (p<0.05) as a food-buying practice within the low SES area and the propensity to compare prices of different brands (p<0.05) as a food-buying practice within the middle SES area. Shopping frequency influenced the use of advertisements (p<0.05) as a food buying practice within the low SES area and co-shopping influenced the propensity to avoid impulse buying (p<0.05 and p<0.001 between the various co-shoppers) as a food-buying practice within the low SES area, as well as the propensity to use advertisements (p<0.05) as a food-buying practice within the high SES area. Gender influenced the use of a shopping list (p<0.05) as a food-buying practice within the high SES area and the use of advertisements (p<0.05), as well as the propensity to avoid impulse buying (p<0.001) as food-buying practices within the middle SES area. Gender also affected the propensity to compare the prices of different brands (p<0.05) as a food-buying practice within the low SES area and among respondents, in general, the propensity to avoid impulse buying (p<0.05), as well as the use of advertisements (p<0.001) as food-buying practices. Employment status affected the use of a shopping list (p<0.05) as a food-buying practice within the high SES area. Population group affected the propensity to use advertisements as a food-buying practice within the low SES area (p<0.05 and p<0.001 between the population groups) and among the respondents, in general, (p<0.05). Household monthly income affected the propensity to compare the prices of different brands (p<0.05) as a food-buying practice within the high SES area. Among the respondents, in general, household monthly income affected the propensity to compare the prices of different brands (p<0.05 and p<0.001 between the income groups) and the use of advertisements (p<0.05) as food-buying practices. The study confirmed that there are differences in the use of food-buying practices among consumers who reside in different SES areas, and further identified specific shopper and demographic characteristics that have an effect on consumers‟ (in general, as well as within the same SES area) use of food-buying practices. Since food-buying practices can be used by consumers to manage their household income expenditure on food, consumer awareness of these practices, in particular the avoidance of impulse buying should be promoted through educational efforts ideally by food retail companies. These companies have the resources and capability to communicate with consumers regularly (while shopping in-store), and can inform their customers about food-buying practices that would help them to save money and/or make additional funds available for other essential household expenses.
122

In vitro propagation of Agathosma betulina an indigenous plant of economic importance

Witbooi, Hildegard January 2013 (has links)
Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Horticultural Sciences in the Faculty of Applied Sciences at the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY Supervisor: Dr L Kambizi Co-supervisor: Dr NP Makunga Cape Town December 2013 / Agathosma betulina (Berg.) Pillans, previously known as Barosma betulina, is a member of the Rutaceae family, and indigenous to the fynbos botanical biome of the Western Cape of South Africa. It is commonly known as buchu. Extracts as well as powdered leaves have traditionally been used for the treatment of various ailments. The increase in the international demand for A. betulina for health as well as food and beverage benefits, have raised concerns over exploitation of wild populations and the lack of horticultural information necessitates this study to evaluate the propagation of this economical important species. The main objective of this study was to establish a simple and highly productive micropropagation protocol for A. betulina through experimenting with nodal explants. Testing of the effect of various treatments (physical scarification, chemical scarification, GA, stratification, smoke and combinations thereof) on the in vitro germination of A. betulina seeds was done to elucidate the factors which control seed germination. The study revealed that the physical scarification and smoke-induced germination had a significant effect on germination percentages. In terms of germination rate, the radical generally started to appear after approximately 10 days in the physical scarification with smoke treatment. Initial decontamination methods with the exposure of various concentrations of NaOCl gave fatal results, however 1.5% NaOCl had more phenolic reactions rather than fungal or bacterial contamination. Interestingly, contamination rates of explants were influenced by the stage of maturity of the explant material. This plant material was used to test different strengths of regeneration media, to ensure that the explants receive ample nutrients. Results made exhibited that ½ MS was the best strength for growing A. betulina nodal explants. Compared comparison between in vitro derived explants and ex vitro collected explants showed that the ex vitro derived explants had significant results, but the explants lost vigour soon after the initial exponential growth leading to the explants dying off. Furthermore, ex vitro decontaminated plant material was not economically viable to continue with. Seedlings derived from germinated seeds appeared to be the preferred method of propagation as this spent the least time in culture and produced a stable plant with an established root system, which is essential during the hardening off process after in vitro growth. When exposing nodal explants to phytohormone 2,4-D it responds best to dosages 0.5mg Lˉ¹ and 1mg Lˉ¹. Phytohormone BA was very effective in producing soft friable callus. The best results were shown when 0.5mg Lˉ¹ BA was applied to ½ MS media. For both shoot length and multiple shoot production, a combination of phytohormones BA-NAA (1: 0.5mgLˉ¹) had the most significant results. Interestingly, a higher phytohormone concentration of NAA is necessary to develop multiple adventitious roots. The effect of 3mg Lˉ¹ was significant in that it resulted in multiple adventitious roots, but fewer calli was observed in this treatment. Micropropagation becomes valuable as little attention between subcultures is needed; making it less labour intensive compared to conventional nursery propagation systems where weeding watering and spraying of plants are labour intensive. In the traditional world of medicine, more so in Southern Africa, extracts are prepared by adding boiling water to the plant material; however commercial ethanol is used as an extractant. Establishment of the essential oil quality of the in vitro cultures post exposure to various treatments was done. Analysis of essential oils from A. betulina resulted in the identification of twenty one compounds. The results showed qualitative as well as quantitative differences amongst the samples used in the study. The highest relative concentration of limonene was observed in the callus of nodal explants after it was exposed to 0.5mg lˉ¹ NAA. No pulegone was found in this treatment making it ideal for limonene production. This suggests that liquid culture with the same treatment may produce more calli making it ideal for the production of limonene.
123

Performance of a symmetrical converging-diverging tube differential pressure flow meter

Ilunga, Luc Mwamba January 2014 (has links)
Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Civil Engineering in the Faculty of Engineering at the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY 2014 / The current problems of orifice, nozzle and Venturi flow meters are that they are limited to turbulent flow and the permanent pressure drop produced in the pipeline. To improve these inadequacies, converging-diverging (C-D) tubes were manufactured, consisting of symmetrical converging and diverging cones, where the throat is the annular section between the two cones, with various angles and diameter ratios to improve the permanent pressure loss and flow measurement range. The objective of this study was firstly to evaluate the permanent pressure loss, secondly to determine the discharge coefficient values for various C-D tubes and compare them with the existing differential pressure flow meter using Newtonian and non-Newtonian fluids, and finally to assess the performance of these differential pressure flow meters. The tests were conducted on the multipurpose test rig in the slurry laboratory at the Cape Peninsula University of Technology. Newtonian and non-Newtonian fluids were used to conduct experiments in five different C-D tube flow meters with diameter ratios (β) of 0.5, 0.6 and 0.7, and with angles of the wall to the axis of the tube (θ) of 15°, 30° and 45°. The results for each test are presented firstly in the form of static pressure at different flow rates. It was observed that the permanent pressure loss decreases with the flow rate and the length of the C-D tube. Secondly, the results are presented in terms of discharge coefficient versus Reynolds number. It was found that the Cd values at 15° drop earlier than at 30° and 45°; when viscous forces become predominant, the Cd increases with increasing beta ratio. The Cd was found to be independent of the Reynolds number for Re>2000 and also a function of angle and beta ratio. Preamble Performance of a symmetrical converging-diverging tube differential pressure flow meter Finally, the error analyses of discharge coefficients were assessed to determine the performance criteria. The standard variation was found to increase when the Reynolds number decreases. The average discharge coefficient values and their uncertainties were determined to select the most promising C-D tube geometry. An average Cd of 0.96, with an uncertainty of ±0.5 % for a range of Reynolds numbers greater than 2,000 was found. The comparison between C-D tubes 0.6(15-15) and classical Venturi flow meters reveals that C-D 0.6(15-15) performs well in turbulent range and shows only a slight inaccuracy in laminar. This thesis provides a simple geometrical differential pressure flow meter with a constant Cd value over a Reynolds number range of 2000 to 150 000.
124

A performance study of a voltage-fed reluctance synchronous machine

Smith, Robert Albert January 2013 (has links)
Submitted to the Department of Electrical Engineering in Fulfilment of the Requirements for the Magister Technologiae in Electrical Engineering at the Cape Peninsula University of Technology SUPERVISOR: E. VOSS NOVEMBER 2013 / The reluctance synchronous machine (RSM) operates on the principle of magnetic reluctance, which is produced through a careful selection of rotor flux barriers and cut-outs. Magnetic reluctivity is the resistance to magnetic flux and can be directly related to the principles of Ohm’s law in electrical circuits. Although reluctance motors have been known for more than 150 years, researchers lost interest when Nikola Tesla’s induction machine (IM) was introduced to industry. Over the last few decades, however, RSMs have shown a lot of potential. They are cheap, robust, reliable, and their rotors can also be used in the stators of IMs. The disadvantage of these machines is an inherently high torque ripple, being the result of its rotor geometry, but the biggest advantage is having a significant reduction in copper losses after the rotor cage has been removed. This advantage drove engineers to investigate, optimise and modify the performance and structure of this machine, which led to the usage of electronic drive systems. The recent advances in technology have allowed researchers to further investigate and modify the design and performance of this special type of machine, with the integration of Finite Element Analysis (FEA) software also making a contribution to the development of the RSM’s current driven systems. The voltage-fed RSM, driven direct-on-line (DOL) from the utility supply, was left in the shadows as the current-fed RSM took reign, but still is, in the author’s opinion, not yet fully analysed. This thesis practically investigates the performance characteristics of the cageless, voltage-fed 3kW RSM in its steady-state operation, under various loads. These performance characteristics are also compared to a RSM driven from a sensorless vector drive (current-fed) to investigate the advantages and disadvantages between the two. Experiments performed on the test bench immediately reveal a limitation to the voltage-fed RSM’s ability to drive higher loads. While the current-fed RSM conveniently reaches 150% of its full-load, the voltage-fed RSM, due to its cageless structure, only reaches 110% of its full-load power. Despite this discovery, the voltage-fed RSM proves to have a lower core loss, harmonic content and torque ripple. Using a FE software package with an integrated source-code, additional parameters such as the dq-axis inductances and currents are also compared and analysed in terms of its reaction to an increase in load. The eddy-current, hysteresis and excess losses are also analysed as well as the harmonic components caused by the geometry of the RSM. For academic purposes, a fair amount of emphasis is placed on the approach to the problem. The preparation for the FE simulation is explained in detail, providing insight into the FE mathematical model as well as parameter acquisition. These parameters include current angle, friction and windage losses, stator resistance, end-winding leakage reactance, core loss and inertia. The results obtained by the FE model are compared to that of the measured results and is found to have an error of only 0.52%. Furthermore, this study attempts to find the feasibility of the voltage-fed RSM’s practicality in modern-day industry. The conclusion is drawn that the voltage-fed RSM could be used as a more elegant alternative to an otherwise over-complicated and over-priced installation.
125

A practical investigation into the measurement of forces on the stator teeth of electrical machines

Bevan, Graeme Rhys January 2013 (has links)
Submitted to the Department of Electrical Engineering in Fulfilment of the Requirements for the Magister Technologiae in Electrical Engineering at the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY SUPERVISOR: E. VOSS NOVEMBER 2013 / Radial and peripheral displacement of stator teeth in electrical machines is known to be the cause of undesired vibration which leads to noise. This thesis serves to investigate the possibility of physically measuring the radial displacement of stator teeth caused by electromagnetic forces which, to the author’s knowledge, has not yet been achieved. A simplified practical approach is adopted in order to address the inherent difficulties attached to this problem, and the measurement of displacement is done by means of an experimental rig where a tooth is subjected to magnetic force acting over an air gap. Three experiments are carried out, each comprising ten tests, the results of which are compared in order to gain some idea as to the magnitudes of displacement which can be expected over a range of applied air gap flux densities. The aim of this work is to observe the displacement response of magnetised EM core material when acted upon by forces, and to see if the measured results agree with the elastic displacement predicted by a wellknown formula. It will be shown that although the measured results are in the same range as the predicted results, there is a deviation from the predicted linearity due to certain characteristics of the force rig, which are explained. The chosen measurement method is capacitive displacement and is shown to be a viable alternative to the more commonly used search coils and vibrometers in past literatures, especially when measuring displacements on the nano-scale. In addition, this study shows the importance of using 3D finite element software to simulate the electromagnetic model when saturation is present in the core of the test specimen. The important findings of this work are discussed in detail, and some ideas put forward, in an attempt to establish a starting point for future related work in the measurement of electromagnetic forceinduced displacement of stator teeth in electrical machines.
126

Development of a remote wireless monitoring system for large farms

Rootman, Adriaan Cornelius January 2012 (has links)
Thesis submitted in fulfilment of the requirements for the degree Master of Technology: Electrical Engineering at the Cape Peninsula University of Technology, 2012 / This research project addresses the unique challenges of extensive farming in terms of monitoring and controlling remote equipment or events. Poorly maintained roads and escalating fuel costs increase difficulty of farming and the time spent on physically monitoring remote sites further reduces financial yields. The research showed that there are very few solutions that implement wireless or electronic technology to overcome the challenges associated with these isolated and arid areas and that a low-cost, long range wireless telemetry solution that is easy to use would be beneficial for the extensive farming industry. It was therefore the aim of this project to develop a remote monitoring and controlling solution that implements wireless technology to convey information of activities around the farm utilising electronic means. To be able to successfully develop a wireless telemetry solution that will accurately meet the needs of this specific sector of industry, market research was conducted. To guide the research, the QFD (quality function deployment) process for product development has been implemented. The research consisted out of various aspects including a survey, financial considerations and international comparisons. The research also aided in the understanding of the day-to-day activities and also the physical parameters of extensive farms. Also, currently available technologies and products were evaluated to establish whether similarities exist that will aid in the development of a new product. The development process was based on the results obtained in the market research and resulted in a wireless telemetry solution that overcame all the design challenges and proved to be technically feasible, successfully addressing the application requirements. Zigbee technology was utilized for wireless communication because it provided an off-the-shelf solution with a number of readily available development platforms from various technology providers. A communication range of up to 6 kilometres with a transmitted power of 11dBm was achieved for point-to-point communication and a mesh network topology has been implemented for even longer range and complete coverage on farms. Various types of measurements have been catered for, with custom-designed instrumentation which enabled measurements such as water levels, movement and analogue signals. Also, a basic user interface was developed to enable the user to monitor or control the equipment or events remotely from a personal computer, locally or even over the internet. The results of this research project showed that by carefully selecting available technologies and understanding the application, it is possible to develop a solution that addresses the monitoring and controlling needs associated with extensive farming. The wireless telemetry system that was developed resulted in a saving equal to 10% of the total expenses of the farms per year. The telemetry system is therefore a financially feasible solution with a payback period of less than 1 year and far below the initial estimated budget. Without the need to physically monitoring equipment and events, an increase in productivity and the expansion of the overall enterprise is a further benefit added unto the monetary savings. In addition to the financial benefits of implementing new wireless technology, this is an opportunity to contribute to a cleaner and more sustained future as a legacy for the next generation by reducing the carbon footprint of the farm.
127

Solvent dependent growth of one-dimensional crystalline ß-FeOOH nanorods

Chowdhury, Mahabubur Rahman January 2014 (has links)
Thesis submitted in fulfilment of the requirements for the degree DOCTOR TECHNOLOGIAE: ENGINEERING: CHEMICAL in the FACULTY OF ENGINEERING at the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY 2014 / Several authors have reported on the use of alcohols – water /or mixed solvents to synthesise metal oxide nanoparticles. However, no systematic study has been carried out to evaluate the effect of mixed solvent on the particle characteristics, although considerable research has been reported, a gap still exists with regard to the effect of the alcohols as solvents on the growth kinetics of nanoparticles. To address these issues, four different alcohols, namely, methanol (MeOH), ethanol (EtOH), propanol (PrOH) and butanol (BuOH) were used as solvents in the synthesis of β-FeOOH particles. The effect of organic solvents on the growth kinetics of β-FeOOH nanorods has been evaluated for the first time in this study. Two-stage growth of akaganeite nanorods has been observed in BuOH and PrOH. The first growth stage follows a typical power law representing Ostwald ripening (OR) kinetic. The second stage was found to be asymptotic and obeyed oriented attachment (OA) kinetic. The proof of the OA kinetic also comes from the HRTEM images of the synthesised particles. Simultaneous occurrence of the two mechanisms was observed in the growth of the particles synthesised in EtOH and MeOH. The rate constants for OR kinetic, KOR, was found to be higher than the rate constant for OA kinetic, KOA, for different solvents used. Preamble The use of a mixed solvent is a new approach in the synthesis and processing of materials. Various researchers have stated that the surface tension of the solvent plays an important role in the formation of uniform nanorods. However, the effect of surface tension was not correlated with the particle growth, earlier, though the dielectric properties of the mixed solvents were only taken into account. Additionally, no quantitative or qualitative relationship was presented between surface tension and particle growth in the literature. In this work an attempt to correlate these two parameters (surface tension and particle growth) with the concentration of the precursor and temperature was made, resulting in an exponential relationship between KOR for the particle growth and surface tension of the alcohols. Furthermore, the relationship between surface tension and particle growth was validated by an independent study using statistically designed experiments to account for the influence of various process variables on the particle growth. The findings in this study obtained from both theoretical and experimental work provides an insight into the relationship between solvent surface tension and particle growth interactions, producing a new piece of information that will further promote our understanding of the formation mechanisms of β- FeOOH growth. The transformation temperature of akaganeite (β-FeOOH) nanorods to hematite (α-Fe2O3) particles was found to be solvent dependent. Thermogravimetric analysis and differential scanning calorimetry were performed to evaluate the effect of alcohol on the thermodynamic stability of the particles. Alcohol as solvent played a significant role in the dehydration property of the synthesised particles. The percentage mass loss of the particles at 300°C decreases linearly with increasing carbon number in the linear alkyl chain of the solvent. The effect of alcohol type on the particle morphology was found to be more pronounced at higher FeCl3 concentrations (>0.5M). Splitting of β-FeOOH nanorods was observed at FeCl3 concentration of 0.7M in BuOH. In PrOH, rectangular morphologies were obtained whereas nanoribbons resulted in surfactant-free conditions. It was found that the nature of anions (chloride vs. nitrate and sulphate) in the precursor salt also influenced the morphology.
128

Performance evaluation and improvement of grid-connected technology

Raji, Atanda Kamoru January 2012 (has links)
Dissertation (DTech(Electrical Engineering))--Cape Peninsula University of Technology, 2012 / The confluence of the limited resources of fossil fuels (e.g. coal, oil and natural gas), environmental degradations leading to climate change, security of supplies and fossil fuels high costs have demanded a tremendous efforts on humanity to seek for a sustainable and unlimited natural energy sources. Amongst these renewable energy sources stands out solar energy because of its ubiquitousness. Solar energy is converted to DC electricity by the photovoltaic effect. Photovoltaic (PV) power systems installed in commercial and industrial buildings are a good example of distributed power generation. Here the energy consumption and production match and thus electricity taken from the grid during daytime peak hours can be reduced. This is beneficial as the transmission losses in the grid are avoided and also transmission need is reduced. The cost effectiveness of a solar energy system has hindered its wide adoption and deployment in terms of the initial capital cost even though it has a zero energy cost and very minimal operating and maintenance costs. Different governments have instituted many financial incentives for fast adoption of PV systems for both residential and commercial applications. However, all these incentives are not sustainable in the longer term forecast. For PV system to attain grid parity requires more than unsustainable approach of many governments providing time limited subsidies. The technical solution to the problem is to reduce the overall system cost through technical innovations. One such method is the adoption of transformerless inverter technology as the grid interface system. Transformerless inverter topology provides galvanic isolation through innovative inverter topology and switching strategies that eliminates problems created by not employing the service of transformer.
129

An effective quality managemnt approach for new product development process

Mali-Swelindawo, Bongiwe January 2012 (has links)
Dissertation submitted in fulfilment of the requirement for the Master of Technology: Quality in the Faculty of Engineering At the Cape Peninsula University of Technology, 2012 / New Product Development (NPD) is a complicated process that determines success or failure of any company engaging in product development processes. Over the past years, due to the current highly competitive market environment, poor management skills, lack of innovation and customer concern, many companies are struggling to develop new products while simultaneously maintaining high quality of each of these new products. Various studies described that quality management is critical to prolong the life cycle of new products. Thus, this study focused on the key success factors of NPD and integrated quality management strategies into NPD process. This study was conducted at a local plastic packaging and load securing company in the Western Cape Province of South Africa. A combination of both qualitative and quantitative research approaches was conducted. Both management (n1=5) the staff members (n2=24) who are involved in the NPD process were selected as samples. A semi-structured questionnaire and several interviews (in-depth and focused group) were utilised for data collection. A statistical programme (SPSS V20) was employed to generate descriptive statistical results and test the reliability of all the variables. The study results identified that the key quality determinants of the NPD process were are NPD reviews, verifications and validations. In addition, for the NPD process to be successful, the company should focus on the development of the NPD strategy, availability of skills and resources including NPD competence, product quality, empowered multidisciplinary teams and effective risk management. Based on the research findings, this study recommends that the company should have more focuses on the areas of customer dissatisfaction, product quality, and prototype planning in their NPD processes.
130

The design, numerical modelling and development of MEMS fabrication process of micro bolometer for use in long wave infrared detection.

Senda, Paul Tudieji January 2013 (has links)
Master of Technology: Mechanical Engineering in the Faculty of Engineering at the Cape Peninsula University of Technology Supervisor:Prof Philander Oscar Bellville Campus Date of submission: April 2013 / The Advanced Manufacturing Technology Strategy (AMTS), predecessor of the Technology Innovation Agency, was a national strategy focused principally on improving collaboration amongst industry, academia and science councils. The aerospace industries and training institutions in particular have been identified as key thrust areas for achieving economic development through the AMTS. Furthermore, the AMTS Aerospace Interest Group has been identified as one of the most important facets of Micro and Nano Manufacturing, Sensors and Electronics Flagship Program. The manufacturing of Micro and Nano Electronics and sensors is essential for South Africa to sustain the technology capability development as seen in developed countries. For example, there is an urgent need to establish a Photo Lithography facility for South African industry and training Institutions. The demand for the new generations of industrial, military, commercial, medical, automotive and aerospace products in South Africa in particular, and in the world in general, has fuelled research and development activities focused on advanced and smart materials. This situation has allowed for the emergence of a new generation of infrared sensors, the bolometer, based on an infrared thermal detection mechanism which is particularly suited to operate at ambient temperature, opening opportunities for achieving low cost infrared imaging systems for both military and commercial applications. This work deals with different South African bolometer membranes of the second prototype in collaboration with the University of Pretoria and Denel Optronics. The bolometer is an infrared thermal sensor that measures thermal radiation by converting said radiation into a temperature change and subsequently measuring the induced change in electrical resistance. The term infrared from Latin Infra, meaning below, is usually applied to wavelengths between 700nm and 1mm. It can be argued that the first occurrence of infrared sensing actually goes back several millennia, when men placed their hands over recently extinguished fire. However, until Herschel’s experiment, this kind of infrared was between the sun and the earth. Thermal imaging, which refers to the ability to measure the temperature of different points on a scene, requires either an array of infrared detectors operating in those wavelength ranges or a way to scan a scene using a single detector. To realise this work, objectives have been assigned to different groups of the consortium represented by CPUT, UP and Denel. Analyses of thirteen bolometer membranes including metal bolometer (Titanium) and Vanadium oxide were assigned to CPUT, reason why this thesis focuses on the modelling, designing and testing of the bolometer membranes. Masks design of the second prototype bolometer test structures includes several thermally isolated bolometer devices. These devices have been modelled and analysed in order to study their electrical and thermal behaviour. / Cape Peninsula University of Technology University of Pretoria Denel Optronics

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