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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.
41

Development and evaluation of an air source heat pump system for biomaterial drying.

Zhang, Ming. January 2014 (has links)
M. Tech. Mechanical Engineering / Discusses the main objective of this research was to perform an experimental investigation into the heat pump drying performance of biomaterials in South African environmental and climatic conditions.Specific objectives to meet the main goal are: to design and construct a heat pump dryer (HPD) according to local conditions; to set up experimental tests and examine the effect of other vital operating conditions such as relative humidity, drying air velocity and ambient temperature; and to analyse the data in terms of the thermal performance of the heat pump and the drying performance of the dryer
42

Effect of accelarator on the curing, chemorheology, thermal and mechanical properties of benzoxazine and benzoxazine epoxy resins.

Botha, Surene. January 2014 (has links)
M. Tech. Engineering: Chemical. / Aims to establish the cure kinetics of the thermosetting systems through the use of rheology and differential scanning calorimetry. Dynamic mechanical and thermal mechanical analyses will be used to ascertain the mechanical properties. The resistance to thermal degradation will be determined by thermogravimetric analysis.
43

Performance investigation of R134a and R404a in a heat pump water heating system.

Sunmonu, Gbenga Adewale. January 2014 (has links)
M. Tech. Mechanical Engineering. / Objectives of this research is to investigate the theoretical performance of the heat pump water heating system using R134a and R404A; to investigate effects of superheating and sub-cooling on the COP and energy consumption of the heat pump system; and to validate the theoretical findings with the experiment results, using the selected environmentally friendly refrigerants.
44

Laser surface alloying of martensitic stainless steel for improved service performance

Adebiyi, Damilola Isaac. January 2012 (has links)
M. Tech. Metallurgical Engineering / Martensitic stainless steel (MSS) metal matrix composite coatings that can accommodate most applications were developed using TiC and stellite 6 as reinforcement powders and Nd: YAG solid state laser for surface alloying. The alloyed surfaces were characterized by means of optical microscopy (OM), scanning electron microscopy (SEM/EDS) and x-ray diffraction (XRD). The microstructures of the alloyed zones show even distribution and super saturation of titanium carbide and other complex carbides of chromium (Cr23C6), niobium (Nb6C5), and iron (Fe7C3) in the matrix of the MSS A significant increase in the hardness was achieved by the addition of stellite 6, although with cracks in the alloyed layer. The cracks formation was due to high heat build-up during the laser alloying process. As a result of the addition of TiC powder in the form of premixed ratio, the heat build-up in the work-piece was minimized. This is due to the high absorptance of laser irradiation by the TiC powder. The alloyed zone of the premixed ratio was free from cracks with microhardness increase of more than 150% of that of the substrate. Multiple tracks of 50% and 75% overlap were fabricated. Three-body abrasive wear study of the overlapped coatings revealed the wear mechanism of the laser coatings to be adhesion, mild abrasive and less degree of deformation showing less plastic ploughing and cutting compared to the as-received. The wear mechanism of the as-received is adhesion, severe abrasive and plastic deformation, showing distinct grooves and damaged spots in the form of craters. The wear resistance of the MMC obtained by alloying with the TiC powder was significantly improved with the 75% overlap, about 90% better than the native material.
45

Comparison of various home water treatment systems and devices for the removal of viral indicators and protozoan parasites

Adeyemo, Folasade Esther. January 2012 (has links)
M. Tech. Water Care. / Aims to evaluate promising technologies for local application in the removal of viruses and protozoan parasites and to provide guidelines for the selection and use of appropriate home water treatment systems that could be used in rural households.
46

Removal of vanadium from industrial wastewater using surface modified eccalite.

Atiba, Opeyemi Alice. January 2013 (has links)
M. Tech. Chemical Engineering. / Evaluates the use of modified eccalite as an adsorbent for the efficient removal of vanadium from industrial wastewater. The specific objectives of the study are: i. To determine whether modification of eccalite with a surfactant such as (hexadecyltrimethylammonium bromide HDTMA-Br, CTAB) will gives an optimal performance in vanadium removal from industrial wastewater; ii. To conduct batch adsorption experiments for modified eccalite for the determination of equilibrium adsorption capacity, kinetics, and thermodynamic parameters; iii. To perform column/dynamic adsorption experiments for modified eccalite in order to determine the dynamic adsorption capacity and breakthrough profiles. iv. Fit the experimental data to existing mathematical model describing the sorption process of vanadium removal from wastewater.
47

Spark plasma synthesis of titanium-manganese oxide composite electrode for supercapacitor application.

Tshephe, Thato Sharon. January 2013 (has links)
M. Tech. Department of Chemical, Metallurgical and Materials Engineering. / Discusses how to synthesize a titanium-manganese oxide composite electrode with improved supercapacitive properties. The research aim was achieved through the following objectives: 1. the mechanisms of the synergistic incorporation of manganese oxide for improving the supercapacitive properties of titanium oxide electrodes. 2. Investigate possible metallurgical interactions and phenomenon during the sintering of the composite. 3. Investigate the electrochemical characteristics of titanium-manganese composite electrodes.
48

Solar water heating and its impact on the energy demand in Botswana.

Mpaesele-Motsumi, Malebogo. January 2013 (has links)
M. Tech. Electrical Engineering. / Discusses the study objectives as follows: 1. Description of the extent of roll-out of SHW (Solar Water Heater) as a DSM (Demand Side Management) Programme in Botswana. 2. Identification of SWH implementation obstacles/barriers in Botswana. 3. Provision of a strategy for SWH data capture and verification in Botswana. 4. Evaluation of SWH performance through field measurements. 5. Prediction of SWH performance results using performance predictive simulation models. 6. Extrapolation/quantification of the impact of SWH. 7. Provision of energy management/planning/forecasting tool.
49

Strength-balance of bitumen stabilised pavements.

Van Wyk, Schalk Willem. January 2013 (has links)
M. Tech. Engineering: Civil. / Discusses the objective of this study was to develop an equation to determine the penetrometer penetration rate (DN) of a pavement consisting of Bitumen Stabilised Material layers are constructed. The aim is to use laboratory results of Bitumen Stabilised Material and study the relations between the Indirect Tensile Strength and the Unconfined Compressive Strength. With the relations a penetrometer penetration rate (DN value in millimetre per blow) can be determined. This will enable the designer to apply the strength-balance concept on a pavement consisting of Bitumen Stabilised Materials. As indicated previously it was found during the design stages that only the Indirect Tensile Strength data on the Bitumen Stabilised Material was available. Developing an equation to convert the Indirect Tensile Strength data to a DN value will allow the designer to apply the strength-balance concept and adjust the design for improved performance life of a pavement.
50

Effects of entrepreneurship education on students' entrepreneurial intentions : a case of Botswana

Ebewo, Patrick Ebong. January 2013 (has links)
M. Tech. Entrepreneurship Tshwane University of Technology / Investigates the relationship between entrepreneurship education and University of Botswana students' intentions towards entrepreneurship. The study also investigates how University of Botswana can expose its students entrepreneurship-related courses at some stage of their study.

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