Engineering
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- ItemThin layer drying of cob maize using a natural convection solar tunnel dryer.(The University of Zambia, 2019) Mukuwa, MukwangoleA semi- cylindrical natural convection Solar Tunnel Dryer (STD) was used for experiments to dry partially field- dried maize cobs with a moisture content of about 30 % wet basis to a safe storage moisture content of 12.5 % wet basis. Air temperatures ranging from 15.8 oC to 20.8 oC above ambient temperature were recorded in the collector unit. The presence of Aflatoxins was investigated for maize dried in the Solar Tunnel Dryer (STD), Open- Sun Drying (OSD) and partially field dried maize gotten Straight From the Field (SFF). The chimney performance was also evaluated. Drying time was examined with moisture content ratio as exponential and polynomial correlations. Fourteen different mathematical models available in literature were compared using their coefficient of determination to estimate solar drying curves. Based on statistical analysis results, Midilli drying model has shown a better fit to the experimental drying data of maize with a coefficient of determination R2 = 0.99912 as compared to other models. The Aflatoxins concentration levels was 8.37 parts per billion (ppb) for maize dried in STD and 11.57 ppb for OSD maize, respectively. The maize which was partially field- dried and tested for Aflatoxins had a concentration of 8.63 ppb. In Zambia, Aflatoxins concentrations above 10 ppb are not allowable. Acceptable Aflatoxins concentrations in the USA is 20 ppb whereas in the European Union countries concentrations of 4 ppb are allowed for ready to eat corn and 10 ppb for corn destined for further processing. In one of the experiments, it took 30 hours to obtain a moisture content of 12.57 % from an initial moisture content of 20.98 % wet basis as compared to 46 hours for OSD. In this experiment, the results show that the designed STD reduced the drying time of maize by 16 hours as compared to OSD. For air movement to take place, the buoyant pressure head in the chimney should be positive. Average values of buoyant pressure head ranged from 0.24645 Nm2 , 0.44859 Nm2 and 0.10819 Nm2 for all the experiments carried out.
- ItemChallenges and opportunities in developing off-grid mini hydropower projects in Zambia.(The University of Zambia, 2019) Mkumba, EdmondMini hydropower plays a critical role in providing energy access to remote areas through mini grids. However, the development of mini hydropower sites has lagged in Zambia with the country only witnessing the construction of two off-grid mini hydropower stations namely, Zengamina and Shiwan’gandu Mini Hydropower Stations in Ikeleng’e and Shiwan’gandu Districts respectively in the last 30 years. The research was undertaken to identify the challenges and opportunities including development of a strategy for implementing off-grid mini hydropower projects in Zambia. The research was designed in such a way that both qualitative and quantitative data were captured. The sampling method used was purposive sampling where experts mainly from the energy sector were targeted representing policy makers, developers, implementing agencies, consultants and regulators among others. Critical challenges identified included high initial investment cost, limited funding, long procedures for obtaining the necessary permits and licenses, low electricity tariffs to encourage private sector participation, lack of skills in the local Zambian contractors and limited market for the power generated. Opportunities included Zambia’s relatively stable political climate, availability of significant hydropower potential, government’s willingness to migrate towards cost reflective tariffs and presence of the required institutional and legal frameworks. High initial investment cost was the most critical challenge in developing off-grid mini hydropower projects in Zambia while the greatest opportunity was the presence of the relatively stable political climate followed by the presence of significant hydropower potential. Following the challenges identified and the opportunities that exist, a strategy for implementing off-grid mini hydropower projects was formulated with integrated planning as the starting point of the strategy. It is also recommended that the government through the institutions overseeing mini hydropower development embraces integrated planning and develop a mini framework and master plan to guide the actual development of such projects in Zambia. Development of off-grid mini hydropower projects would contribute to increasing the electricity access rate in rural areas which stands at 4.4% as at 2015.
- ItemWeb and mobile based examination results dissemination and verification system using authenticated encryption : a case of technical education vocational and entrepreneurship training authority.(The University of Zambia, 2019) Mseteka, ListerABSTRACT Institutions of higher learning retain sensitive data making them highly attractive targets for cybercrime . However, most developing countries and public higher institutions of learning have low levels of I nformation and C ommunication T echnology (ICT) and hence face challenges in securing inform ation and information systems. Therefore, the dissemination of students’ examination results by public higher institutions through web and mobile applications usually raise security concerns on how to ensure the confidentiality, integrity and authenticity of students’ examination results due to susceptibility of web and mobile applications to cyber attacks In this study, a model was designed for secure storage and dissemination of students’ examination results using encryption and cryptographic hash functi ons to provide information security objectives of confidentiality, integrit y and authenticity assurances on students’ examination results. T he study was guided by three (3) objectives. A baseline study was conducted to determine the challenges faced by Zam bia’s Technical Education, Vocational and Entrepreneurship Training Authority (TEVETA) and students regarding dissemination of students’ examination results in order to address objective number one (1). The results from the study indicate that the current TEVETA business processes have a number of irregularities. These include candidate registration, storage of students’ examination results and dissemination of students’ examination results. The results from the baseline study were used to design a model wh ich was then used to develop the prototype in order to address the second (2) and third (3) objective. The results obtained from the test and evaluation of the developed prototype based on the model showed not only improved efficiency in dissemination of e xamination results but also confidentiality of students’ results through encryption as well of integrity of students’ examination results through detection of altered students’ examination results during transmission and storage through cryptographic hash function.
- ItemEstimation of irrigation water abstraction in the upper reaches of Lunsemfwa, Mulungushi, Mwomboshi and Mkushi sub-basins.(The Univeristy of Zambia, 2018) Tshenyego, LamongWater abstraction is achieved by many means, and for many purposes. Abstraction depends on many variables that include the purpose for the abstraction, the location, the type of laws in place regarding the procedure, and the type of resources available for the abstraction process. The overall objective of the study was to estimate the abstraction for irrigation water from the upper reaches of Mkushi, Mulungushi, Mwomboshi and Lunsemfwa sub-Basins. For the years 2013–2017 Landsat (L8OLI/TIRS), QGIS and AquaCrop packages were used to generate water abstraction estimates. Field and climate data was obtained from the internet and literature as well as weather stations under Southern African Science Service Centre for Climate Change and Adaptive Land Management (SASSACAL) project closer to the sub-catchments. Reference evapotranspiration was determined using FAO ETo calculator and ranged from 6.84 mm/day to 7.02mm/day. The QGIS software was used to delineate the catchments areas. Mwomboshi had a smallest catchment area of 3043 km2, while Lunsemfwa had largest area of 7794 km2. Classified estimates of irrigated areas within each sub basin under the study were for the period 2013 to 2017. The least recorded irrigated area was in Mkushi in 2016 (12 km2) while highest being 167 km2 in Lunsemfwa in 2013. For the five years period (2013 to 2017) Mkushi has irrigated a sum of 103.83 km2, Lunsemfwa 692.00 km2, Mulungushi 136.00 km2 and Mwomboshi with the sum of 115.17 km2. For this study the soils were set as described by in the soil map of Zambia and put into the soil Characteristic calculator to estimate their physical properties. The results show that maximum volume of water abstracted in all the catchment was estimated at 120,203,800 m3 in 2013, while the minimum was in 2014 estimated at 73,366,400 m3. The results show that for maximum volume abstracted for irrigation had a significant difference when comparing Lunsemfwa catchment to Mkushi. Mulungushi and Mwomboshi show no chances of being the same at alpha of 0.05 level.
- ItemUsage of mobile money services : a case of mobile network operator systems.(The University of Zambia, 2019) Phiri , Mwiza NorinaMobile money which refers to the use of mobile phones to perform financial and banking functions has increasingly become popular in the world today. Not only has mobile money brought advantages of convenience, safe transactions, 24 hours access to its users, mobile money has also created a great revenue base for service providers. Zambia was one of the first countries in Africa where Mobile Money was launched. As early as 2001, various Zambian businesses including MNO began to provide mobile money services. By 2014, the Bank of Zambia announced that the number of mobile money accounts had exceeded the traditional bank account. Adoption of mobile services has been reported to be high however active usage has not followed. The purpose of this study is to investigate the usage of MNO mobile money services in Zambia. The study aims to determine the factors that affect the use of mobile money system and to determine way in which usage of MNO mobile money can be enhanced. The study adopted cross-sectional survey to collect quantitative data from users of mobile money services. It also included agents and service providers’ representatives from Airtel Money, MTN mobile money in Lusaka district of Zambia. Extending Technology Acceptance Model (TAM) framework, a self-administered questionnaire was prepared and circulated in Lusaka province. From the 200 questionnaires circulated, 112 useable questionnaires were returned (56% response rate) and subsequently analysed using SPSS and excel. The study findings revealed that usage of MNO mobile money services was generally low with 21.6 % monthly users compared to other comparable nations such as Kenya and Tanzania where usage is approximately over 50% monthly. It was found that there are significant challenges affecting market penetration, expansion and regular use of mobile money. The most prevalent challenge being limited acceptability of the service. Zambia has limited number of mobile money access and trading point compared to comparable countries such as Tanzania Kenya and Uganda. Only 2% of the contacted retailers accepted mobile money as a mode of payment and cash was the most predominately used medium of exchange. Other challenges include Liquidity problems for agents, unavailability of network coverage, regulations and system failures for mobile money payment systems Improving the MNO agent network, improving the liquidity of agents by partnering with more stable financial institutions, reduction of cross network transaction charges, improving the stability of network, training and information to users are necessary measures to increase usage, penetration and expansion of mobile phone money services.