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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.
31

Investigation of bacterial ferrous iron oxidation kinetics in a novel packed-column reactor: pH and jarosite management

Wanjiya, Mwema January 2013 (has links)
Thesis submitted in fulfilment of the requirements for the degree of Masters of Technology: Chemical Engineering in the Faculty of Engineering Cape Peninsula University of Technology, South Africa Supervisor: Prof TV Ojumu Cape Town Campus September 2013 / Jarosite formation is regarded as undesirable in the bioleaching processes as it depletes ferric reagent; a critical reagent for the oxidation of most sulphide minerals, from bioleach solution. It creates kinetic barriers and clogs on mineral surfaces, thereby retarding leach rates of most minerals. However, jarosite has also been shown to serve as support for the attachment of bioleaching microbes, facilitating a high ferric-iron generation rate. In this study, a series of experiments on microbial ferrous-iron oxidation by a mesophilic microbe were carried out in a novel packed-column bioreactor with a view to investigating the potential use of solution pH to manage jarosite accumulation in the bioreactor. The kinetics of the oxidation was also investigated to establish base case data for the novel bioreactor. The bioreactor was packed with glass balls 15 mm in diameter. The experiments were conducted at a constant temperature of 38.6 °C, residence time of 18 hrs, airflow rate of 20 mL.s-1 and at desired solution pHs (1.3, 1.5 and 1.7). The results showed that the amount of jarosite accumulation is proportional to the operating solution pH and also to the duration of operation of the bioreactor. Jarosite precipitate of 4.95, 5.89 and 7.08 g.L-1 were obtained after 10 days of continuous operation at solution pH of 1.3, 1.5 and 1.7 respectively, while after 15 days the precipitate concentration increased to 5.50, 7.90 and 9.98 g.L-1respectively. The results also showed that a 33% and 52% reduction in jarosite accumulation could be achieved by a gradual decrease of the bioreactor solution pH after being continuously operated for 10 days from pH 1.7 to 1.5 and pH 1.7 to 1.3, respectively, for an additional five days of continuous operation. The results of the ferrous-iron biooxidation kinetics investigated at pH 1.3 show a maximum ferrous oxidation rate ( max 2 Fe r ) of 6.85 mmol.L-1.h-1 and apparent affinity kinetics constants (   2 Fe K , 2 Fe K ) of 0.001 mmol Fe2+.L-1 and 0.006 (dimensionless) using Hansford and Monod equations, respectively. Although a direct relationship exists between jarosite formation and solution pH, the results of this study may be relevant in bioleach heaps, or at least in column bioreactors, to manage and control jarosite accumulation, thereby improving leach kinetics of sulphide minerals.
32

Investigation of bacterial ferrous iron oxidation kinetics in a novel packed-column reactor: pH and jarosite management

Wanjiya, Mwema January 2013 (has links)
Thesis submitted in fulfilment of the requirements for the degree of Masters of Technology: Chemical Engineering in the Faculty of Engineering Cape Peninsula University of Technology, South Africa, 2013 / Jarosite formation is regarded as undesirable in the bioleaching processes as it depletes ferric reagent; a critical reagent for the oxidation of most sulphide minerals, from bioleach solution. It creates kinetic barriers and clogs on mineral surfaces, thereby retarding leach rates of most minerals. However, jarosite has also been shown to serve as support for the attachment of bioleaching microbes, facilitating a high ferric-iron generation rate. In this study, a series of experiments on microbial ferrous-iron oxidation by a mesophilic microbe were carried out in a novel packed-column bioreactor with a view to investigating the potential use of solution pH to manage jarosite accumulation in the bioreactor. The kinetics of the oxidation was also investigated to establish base case data for the novel bioreactor. The bioreactor was packed with glass balls 15 mm in diameter. The experiments were conducted at a constant temperature of 38.6 °C, residence time of 18 hrs, airflow rate of 20 mL.s-1 and at desired solution pHs (1.3, 1.5 and 1.7). The results showed that the amount of jarosite accumulation is proportional to the operating solution pH and also to the duration of operation of the bioreactor. Jarosite precipitate of 4.95, 5.89 and 7.08 g.L-1 were obtained after 10 days of continuous operation at solution pH of 1.3, 1.5 and 1.7 respectively, while after 15 days the precipitate concentration increased to 5.50, 7.90 and 9.98 g.L-1respectively. The results also showed that a 33% and 52% reduction in jarosite accumulation could be achieved by a gradual decrease of the bioreactor solution pH after being continuously operated for 10 days from pH 1.7 to 1.5 and pH 1.7 to 1.3, respectively, for an additional five days of continuous operation. The results of the ferrous-iron biooxidation kinetics investigated at pH 1.3 show a maximum ferrous oxidation rate ( max 2 Fe r ) of 6.85 mmol.L-1.h-1 and apparent affinity kinetics constants (   2 Fe K , 2 Fe K ) of 0.001 mmol Fe2+.L-1 and 0.006 (dimensionless) using Hansford and Monod equations, respectively. Although a direct relationship exists between jarosite formation and solution pH, the results of this study may be relevant in bioleach heaps, or at least in column bioreactors, to manage and control jarosite accumulation, thereby improving leach kinetics of sulphide minerals.
33

Investigation of methodologies for fault detection and diagnosis in electric power system protection

Adewole, Adeyemi Charles January 2012 (has links)
Thesis Submitted in fulfilment of the requirements for the degree Master of Technology: Electrical Engineering in the Faculty of Engineering at the Cape Peninsula University of Technology, 2012 / The widespread deregulation and restructuring of electric power utilities throughout the world and the surge in competition amongst utility companies has brought about the desire for improved economic efficiency of electric utilities and the provision of better service to energy consumers. These end users are usually connected to the distribution network. Thus, there is a growing research interest in distribution network fault detection and diagnosis algorithms for reducing the down-time due to faults. This is done so as to improve the reliability indices of utility companies and enhance the availability of power supply to customers. The application of signal processing and computational intelligence techniques in power systems protection, automation, and control cannot be overemphasized. This research work focuses on power system distribution network and is aimed at the development of versatile algorithms capable of accurate fault detection and diagnosis of all fault types for operation in balanced/unbalanced distribution networks, under varying fault resistances, fault inception angles, load angles, and system operating conditions. Therefore, different simulation scenarios encompassing various fault types at several locations with different load angles, fault resistances, fault inception angles, capacitor switching, and load switching were applied to the IEEE 34 Node Test Feeder in order to generate the data needed. In particular, the effects of system changes were investigated by integrating various Distributed Generators (DGs) into the distribution feeder. The length of the feeder was also extended and investigations carried out. This was implemented by modelling the IEEE 34-node benchmark test feeder in DIgSILENT PowerFactory (DPF). In the course of this research, a hybrid combination of Discrete Wavelet Transform (DWT), decision-taking rule-based algorithms, and Artificial Neural Networks (ANNs) algorithms for electric power distribution network fault detection and diagnosis was developed. The integrated algorithms were capable of fault detection, fault type classification, identification of the faulty line segment, and fault location respectively. Several scenarios were simulated in the test feeder. The resulting waveforms were exported as ASCII or COMTRADE files to MATLAB for DWT signal processing. Experiments with various DWT mother wavelets were carried out on the waveforms obtained from the simulations. In particular, Daubechies db-2, db-3, db-4, db-5, and db-8 were considered. Others are Coiflet-3 and Symlet-4 mother wavelets respectively. The energy and entropy of the detail coefficients for each decomposition level based on a sampling frequency of 7.68 kHz were analysed. The best decomposition level for the diagnostic tasks was then selected based on the analysis of the wavelet energies and entropy in each level of decomposition. Consequently, level-1 db-4 detail coefficients were selected for the fault detection task, while level-5 db4 detail coefficients were used to compute the wavelet entropy per unit indices which were then used for fault classification, fault section identification, and fault location tasks respectively. Decision-taking rule-based algorithms were used for the fault detection and fault classification tasks respectively. The fault detection task verifies if a fault did indeed occur or not, while the fault classification task determines the fault class and the faulted phase(s). Similarly, Artificial Neural Networks (ANNs) were used for the fault section identification and fault location tasks respectively. For the fault section identification task, the ANNs were trained for pattern classification to identify the lateral or segment affected by the fault. Conversely, the fault location ANNs were trained for function approximation to predict the location of the fault from the substation in kilometres. Also, the IEEE 13 Node Benchmark Test Feeder was modelled in RSCAD software and batch mode simulations were carried out using the Real-Time Digital Simulator (RTDS) as a ‘proof of concept’ for the proposed method, in order to demonstrate the scalability, and to further validate the developed algorithms. The COMTRADE files of disturbance records retrieved from an external IED connected in closed-loop with the RTDS and the runtime simulation waveforms were used as test inputs to the developed Hybrid Fault Detection and Diagnosis (HFDD) method. Comparison of the method based on entropy with statistical methods based on standard deviation and Mean Absolute Deviation (MAD) has shown that the method based on entropy is very reliable, accurate, and robust. Results of preliminary studies carried out showed that the proposed HFDD method can be applied to any power system network irrespective of changes in the operating characteristics. However, certain decision indices would change and the decision-taking rules and ANN algorithms would need to be updated. The HFDD method is promising and would serve as a useful decision support tool for system operators and engineers to aid them in fault diagnosis thereby helping to reduce system down-time and improve the reliability and availability of electric power supply. Key words: Artificial neural network, discrete wavelet transform, distribution network, fault simulation, fault detection and diagnosis, power system protection, RTDS.
34

Variable Stroke Crank Shaft for an Internal Combustion Engine

Ismail, Fareed January 2012 (has links)
Thesis submitted in fulfilment of the requirements for the degree of Master of Technology in Mechanical Engineering in the Faculty of Engineering at the Cape Peninsula University of Technology, 2012 / Our planet is continuously being depleted of its natural resources leading to a need to conserve energy and the environment. One of the major energy consumers is the conventional internal combustion engine. Many attempts have been made to make these conventional internal combustion engines more efficient focussing mostly on the combustion side of the engine. The focus of this study is on the modification of the reciprocating and rotating components of the sub-assembly of a conventional internal combustion engine. An in-depth review was carried out on the fundamentals of spark ignition internal combustion engines and savings on fuel consumptions. A prototype single piston internal combustion engine was developed that can adjust its stroke length. Lengthening or shortening the stroke and simultaneously extending or retracting the connecting rod’s travel distance, allows the internal combustion engine to function very efficiently consequently reducing the free space between the piston and cylinder head at TDC position. This allows the internal combustion engine to alter its power capability on demand whilst maintaining relatively high compression efficiency. The method of altering the stroke length is achieved by manipulating gears situated internally and externally of the engine sub-assembly. The control of these eccentric gears lowers or lifts the crankshaft in a radial motion. The eccentrics also control the automatic extension or retraction of the connecting rod’s travel distance. The externally concentric gears control the mechanism that allows the internal combustion engine to change its capacity easily as adapted for automation. This study does not extend into the automation issues of the external mechanism. The prototype engine that was built could not endure vigorous testing and it failed after running for a short while. The primary focus had been on the kinematics of the engine mechanism – and to show whether the idea was feasible. The engine passed the kinematics test but failed possibly due to dynamic loads. Investigating this requires measuring instantaneous temperatures from which peak pressures can be deduced. This was not done because it was outside the scope of the project.
35

Deformation and damage analysis of composite beams equipped with polyvinylidene fluoride film sensors

do Nascimento Oliveira, Jose Emidio January 2008 (has links)
In many engineering applications, it is desirable to know the behaviour of structures and systems under loading conditions. One reason is to help optimize the design and prevent damage and failure which might occur during in service and operation. Damage represents a serious problem which can cause catastrophic failure of structures, machines and systems. Therefore for safe operation, efficient and reliable methods for inspection and monitoring of damage are required. Different methods for health monitoring of structures such as non destructive testing (NDT) and strain gauges are widely used. These methods have proven to be efficient in terms of resolution and response. However, some disadvantages associated with them include the vicinity of the area under inspection which must be well known, equipment to acquire the necessary information is expensive and in many cases high skills are required for operation. On the other hand, advances in materials science and MEMS systems has promoted the use of new materials with piezoelectric properties. This include mainly polymeric and ceramic materials which after processed can be used for structural health monitoring. These materials offer a number of advantages such as lightweight, sensitivity, toughness, durability, and low cost. The present research work investigates the feasibility of using a polymeric material, Polyvinylidene Fluoride (PVDF) as a sensor for deformation and defect detection in structures. The sensors are embedded in composite cantilevered type beams to detect defects at distinct locations along the beam’s length. The defect detection method proposed is based on experimental tests and Finite Element simulations. Experimental tests on defect free and beams with manufactured internal flaws were conducted. Numerical (FEM) simulations of defect free and flawed beam models containing sections of reduced elastic modulus to represent the damage were conducted using ANSYS software. The experimental tests have been used for the validation of the numerical solution. Results have shown that the defect location changes the stiffness and indeed the frequency of vibration. For flaws near the fixed end of the beams, lower frequencies are obtained as compared to flaws away from the fixed end. PVDF sensors were used to acquire the natural frequencies of the beams for the first mode of vibration. Good agreement was verified between experimental and numerical simulation results. The work has demonstrated that PVDF film sensors can be used as possible candidates for defect detection. The analysis of the behaviour embedded PVDF sensors near the fixed end of cantilever beams, represents an initial and important step towards the application of measuring static and dynamic behaviour of structures as part of a health monitoring process.
36

Analysis of innovative leadership and sustainability of SMEs in the Western Cape Province, South Africa

Maladzhi, Wilson Rendani January 2012 (has links)
Thesis submitted in fulfilment of the requirements for the degree Doctor of Technology: Mechanical Engineering in the Faculty of Engineering at the Cape Peninsula University of Technology, 2012 / Over the years, many organisations are constantly under extreme pressure for their survival and sustainability due to globalization, rapid pace of technological innovation and growing knowledge of their customers. Leaders within the Small and Medium Enterprises (SMEs) struggle in dealing with these pressures due to lack of management skills, market know-how, education and training, entrepreneurial drive, technological orientation, product distribution and networking, particularly when compared with large companies. Innovative culture becomes a major problem among these SMEs. This forces leaders to establish a sound environment where employees can be creative and innovative. However, innovative culture is relatively at a slow pace in South Africa compared with other countries. In an attempt to create an innovative environment for employees, many leaders introduced international based policies such as organisational restructuring and reengineering. Instead of these policies to ease the prevailing conditions, the stress levels within the workplaces elevated and crushed the little creativity left in them. Therefore, this study is undertaken to investigate the appropriate leadership style capable to spearhead the SMEs in instilling local based innovation culture for sustainability in the Western Cape, South Africa. A group of participants including both employees (n1=336) and leaders (n2=130) took part in the research survey within 50 SMEs in the Western Cape. Nevertheless, different sample sizes were utilised in various stages through different case studies. This study has adopted the survey research method for its reliability and being quantitative in nature originated from positivism paradigm. An innovative leadership model covered the key characteristics of leadership was developed to achieve the research objectives. All the characteristics as variables were formulated into propositions and hypotheses to determine the state of innovative culture in these SMEs. Cronbach's-Alpha coefficient was used for reliability test of all the characteristics. In addition, descriptive statistical results such as means, standard deviations, correlations, and Chi-Square were generated. The study results revealed that all leadership characteristics variables were found to have p values below (0.01) which suggested on the rejection of null hypotheses. From employees’ point of view, the results showed that the leaders lack inspirational and motivational and high gain risk-taking characters. Thus, employees were not satisfied with their management styles toward innovation. However, leaders rated themselves highly based on the responses. In essence, a mathematical model was also used to analyse the impact of innovative leadership on productivity and profitability. The research findings have confirmed that leadership has the ability to stimulate both productivity and profitability. The study results further indicated that innovative leadership contributed to low production costs that resulted in the increase of productivity and profitability. This study concluded that innovative leadership was vital to the innovative culture within SMEs. The proposed leadership model can be used as a guideline for SMEs to create innovative culture. Moreover, the mathematical model can be utilised for any SMEs to predict their productivity and profitability. ii The rest of the thesis is organized as follows: Chapter one emphasises on the research problems pointing out factors that affected leadership in South African SMEs. The importance of the SMEs in the economy of the country as well as their descriptions and definition of SMEs were discussed. The problem statement, research objectives, leadership definitions, research propositions were highlighted. A description of the proposed model was detailed, and finally, the significance of the study and ethical issues were addressed. Chapter two focused on improving new product development (NPD) through innovative leadership qualities. In this regard, the key factors bearing the impact on NPD such as lack of understanding customer needs, business skills and understanding of innovation in NPD. Chapter three discussed the impact of innovative leadership on organisational culture within SMEs in the Western Cape, South Africa. It outlined the key leadership characters such as visionary, passionate, charismatic, inspirational and motivational, immersed in progressive change, high gain risk taking, ability to network and fast and action oriented leadership, and how these characteristics influence leadership to create an innovative culture within SMEs. Chapter four highlighted how passionate and charismatic leadership impacted creativity and innovation within the SMEs. The leaders in these SMEs were passionate and charismatic. However, it is not sufficient to instill an innovative culture. Chapter five presents an approach on how to create an innovation culture through visionary leadership in the SMEs. The results revealed that employees were very satisfied with their leaders. However, the leaders needed to make more efforts in making employees to embrace their organisational vision in order to be competitive. Chapter six alluded on the developed mathematical model to analyse the impact of innovative leadership on organisational sustainability in terms of productivity and profitability. The mathematical model predicts how changes of innovative leaders influence the increase of profits while production costs decreasing. Chapter seven concluded the importance of innovation culture within the SMEs. This chapter also indicated that there is a tremendous lack of innovation drive within the leaders in the SMEs; such that employees are not motivated enough to bring new ideas that can add organisational values. The further study areas were highlighted as well. Keywords: Innovation, leadership, culture, new product development, sustainability and SMEs
37

Laminar flow in a channel filled with saturated porous media

Rundora, Lazarus January 2013 (has links)
Thesis (DTech (Mechanical Engineering))--Cape Peninsula University of Technology, 2013 / The flow of reactive viscous fluids in porous media presents a theoretically challenging problem and has a broad range of scientific, technological and engineering applications. Real life areas where such flow systems are encountered include drying of food, geothermal energy extraction, nuclear waste disposal, the flow of heat and fluid inside human organs, insulation of buildings, groundwater movement, oil and gas production, astrophysical plasmas, magnetohydrodynamic (MHD) pumps and generators, metal extraction and granulation of metals, aerospace and ship propulsion and automobile exhaust systems. The reactions within such flow systems are inherently exothermic. It is in this view that we carry out studies of thermal effects and thermal stability criteria for unsteady flows of reactive variable viscosity non-Newtonian fluids through saturated porous media. The study focuses on non-Newtonian fluids mainly because the majority of industrial fluids exhibit non-Newtonian character. Particular focus will be on fluids of the differential type exemplified by third grade fluid. Both analytical and numerical techniques were employed to solve the nonlinear partial differential equations that were derived from the conservation principles, namely the principles of conservation of mass, momentum and energy balance. Graphical representations were adopted in trying to explain the response of solutions to various flow parameter variations. In chapter 1 we defined important terms and expressions, laid down a summary of important applications, carried out literature survey, stated the statement of the problem, the aims and objectives of the study as well as an outline of the envisaged research methodology. Chapter 2 focuses on the derivations of the fundamental equations that derive the flow system. These are the continuity equation, the momentum equation and the energy equation. In chapter 3 we computationally investigated the unsteady flow of a reactive temperature dependent viscosity third grade fluid through a porous saturated medium with asymmetric convective boundary conditions. The response of velocity and temperature fields to each of the various flow parameters was analysed and interpreted. A transient increase in both the velocity and temperature profiles with an increase in the reaction strength, viscous heating and fluid viscosity parameter was observed. On the other hand, a transient decrease in the field properties was observed with increase in non-Newtonian character and the porous medium shape parameter. The reaction was noticed to blow-up if, depending on other flow parameters, the reaction strength is not carefully controlled.
38

Creative education: the design of web-based learning environments for design students

Morris, Amanda S January 2012 (has links)
Thesis submitted in fulfilment of the requirements for degree Master of Technology: Graphic Design In the Faculty of Informatics and Design At the Cape Peninsula University of Technology, 2012 / The current studio based approach in design education is not enough to keep the “new age” design students’ attention and a blended learning environment is needed to facilitate student engagement. Multiple learning preferences exist within the design classroom and design educators must consider this when designing a curriculum. The research asked what the considerations were when designing the online component of a blended learning environment to enhance the learning experience of and engage design students? The areas of investigation included: • The learning preferences in a specific group of graphic design students to see if there are any predominant preferences, • Whether the web-based learning environment enriched the learning experience and whether students gained understanding of the dynamics of the intervention • Whether there were links between learning preferences, online performance and in-class performance and how we could use these links to design blended learning materials that: o Incorporate collaborative problem solving (Vygotsky, 1978) o Encourage the building of design knowledge (Schon and Wiggins 1992) o Help students move from the periphery of the community of practice to the core (Wenger 1998) o Simulate the world of work (Jonassen et. Al 1998) o Consider the individual learning preferences of students and engages them on multiple levels (Cazden et al 1996) This research concluded that a blended learning environment is necessary in order for design education to move forward and be inclusive. The new generation design curriculum needs to stimulate at many different levels using multiple ways and media. This multimodal stance in design education will afford students the opportunity to become reflective knowledge builders who are able to solve problems collaboratively and transfer existing knowledge to new contexts.
39

Mobile learning as a paradigmatic mechanism to faciliate technology-based learning in a developing country

Le Roux, Suzaan January 2013 (has links)
Thesis submitted in fulfilment of the requirements for the degree Doctor of Technology: Information Technology in the Faculty of Informatics and Design at the Cape Peninsula University of Technology, 2013 / During the last few years it has become evident that first-year undergraduate computer science programming learners in the Financial Information Systems (FIS) programme at the Cape Peninsula University of Technology (CPUT) in South Africa, encounter numerous barriers to successfully practice their programming skills, as well as to design, develop, test and electronically submit their computer science programming assignments. As a result, the formative and summative assessment marks of these learners over the past few years indicate a concerning downward trend year on year, a challenge with which most first-year learners find it difficult to come to terms with. This is primarily due to a plethora of obstacles that impede on learners' ability to complete and electronically submit their programming assignments, especially off-campus, as well as the inability to practice their programming skills outside the boundaries of the classroom. Upon investigation it was determined that this trend is primarily attributed to three major stumbling blocks, namely the limited availability of computers, the absence of the required software needed to complete programming assignments off-campus, and the limited availability of Internet access off-campus.
40

The effect of Rooibos on trace elements absorption and biochemical parameters-Amurine model

Kunsevi-Kilola, Carine January 2014 (has links)
Thesis submitted in fulfillment of the requirements for the degree Master Technologiae: Biomedical Technology In the Faculty of Health and Wellness Sciences At the CAPE PENINSULA UNIVERSITY OF TECHNOLOGY 2014 / Over the past few decades, it has been shown that various critical diseases including heart disease, cancer, and diabetes associated with free radical generation and low endogenous antioxidant capacity, lead to oxidative stress and cell injury. In recent years, numerous studies have also reported that antioxidants, present in various beverages, vegetables and some foods have attracted a significant research interest due to their potential benefits to human health. However, epidemiological evidence shows a correlation between the intake of food rich in antioxidants and the reduced incidence of some mortality of chronic diseases, certain cancers and coronary heart disease. The aims of this study were to determine the effects of rooibos teas (fermented and unfermented) and green tea as a comparison on the biochemical parameters and the trace element absorption in a rat model. In this study 4 groups of experimental animals were used. All groups had ad libitum access to standard rat chow. Group A, the controls (11 animals), were fed with tap water; group B (11 animals) were fed with the liquid extract of fermented rooibos tea; group C (9 animals) were fed with the liquid extracts of unfermented rooibos and group D (9 animals) were fed with the liquid extract of green tea. All groups were fed for a period of 10 weeks. After the feeding period, the animals were sacrificed by euthanization with intraperitoneal injections of pentobarbital. Blood was sampled by cardiac puncture and centrifuged to obtain the serum. Some elemental analyses were performed with X-ray emission and backscattering. ICP-OES was used to determine the magnesium content. For X-ray emission, backscattering and ICP-OES analyses, 100 μL of each serum sample in a group were added to 2 mL freeze-drying tube. Of the combined specimen, 100 μL was used for the magnesium determination by ICP-OES. The remainder of the combined serum specimens for each group were freeze-dried at -80 ºC and then pressed into a pellet. The pellet was coated with carbon and analyzed using X-ray emission and backscattering. The elemental X-rays of P, S, Ca, Mn, Fe, Cu, Co, Zn, Mo, Ca and Se emitted were quantified to obtain the respective concentrations. Biochemical chemistry analyses were performed on each serum sample of each animal. The biochemical parameters tested for were total protein, albumin, globulin, total bilirubin, lactate dehydrogenase, blood urea nitrogen, uric acid, total cholesterol, aspartate aminotransferase, alanine aminotransferase, creatine phosphokinase and creatinine. The P concentration increased (p=0.028) when fed with the fermented rooibos tea liquid extract and S content increased when fed with the - the unfermented tea liquid extract (p=0.041). The concentrations of Cl and Cr were not affected (p>0.05) by any of tea liquid extracts. The unfermented rooibos tea liquid extract and the green tea indicated a decrease in the concentrations of Fe (p=0.031 and p=0.032, respectively) and Mn (p=0.041 and p=0.034, respectively). The concentrations of Fe, Zn and Cu in the serum increased when feeding with fermented rooibos tea liquid extract (p=0.024; p=0.030 and p=0.015, respectively) while Se, Mo and Mg concentrations were decreased by the liquid extracts of the fermented, unfermented and green teas (p=0.014, p=0.017 and p=0.011; p=0.024, p=0.026 and p=0.019; p=0.031, p=0.034 and p=0.025, respectively). Concerning the biochemical parameters, the total protein, globulin and the uric acid contents in the serum sample were slightly affected with the green tea extract (p=0.041, p=0.039 and p=0.047 respectively). The albumin, lactate dehydrogenase, blood urea nitrogen, the total cholesterol, the alanine aminotransferase and the aspartate aminotransferase concentrations were not affected (p>0) by any of the tea liquid extracts. However, the total bilirubin content was decreased (p=0.012) when feeding with the fermented rooibos group while the creatine phosphokinase and the creatinine contents were decreased (p=0.042 and p=0.033, respectively) when feeding with the unfermented rooibos tea liquid extract.

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