Browsing by Author "Matofali, Alex Xavery"

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Investigation of effect of rock storage system parameters on thermal cooling performance
(Science Publishing Group, 2016-01-15) Matofali, Alex Xavery; Massawe, Estomih S.
We investigate the effects of key parameters of the rock bed system on thermal cooling performance of the system after a fixed time of operation. The method of solving the mathematical model uses a semi-discretization finite difference approximation for discretizing space in solid problem domain. A finite element approximation is used in the fluid problem domain. Graphical results on the effects of parameter variation on damping and time delay on the peaking of the outlet air temperature through the bed are presented and discussed.
Optimal control analysis of a cholera disease transmission model in Tanzania
(IJSRSET, 2018) Ainea, Neterindwa; Matofali, Alex Xavery; Mkwizu, Michael
In this paper, a deterministic model with optimal control of cholera in Tanzania is proposed and analysed. Necessary conditions of optimal control problem were rigorously analysed using Pontryagin's maximum principle and the numerical values of model parameters were estimated using maximum likelihood estimator. Two control strategies were incorporated such as human education campaign and treatment of water (to reduce the growth of the organism) and its' impact were graphically observed. The goal is to minimize the spread of cholera disease in the community and to minimize the costs of control strategies. The results show that the effective use of optimal human education campaign and treatment of water has a significant impact in reducing the spread of the disease in the community.
Optimization of thermal cooling Parameters applied to rock Storage systems
(2015) Matofali, Alex Xavery
This study presents a mathematical model for thermal energy storage in low energy buildings. The cooling system which uses rock bed for storing night cooling to be used later for daytime air conditioning is presented. The work initially focuses on the mathematical descriptions of the thermal cooling applied to rock storage system. A numerical method of solution is outlined and the results are compared with measured data at the outlet of the bed both using the measured inlet temperature. A good agreement of trend is observed. The results show two effects of the cooling system on the air temperature, which are damping and time delay of the peaking. The differences are examined through sensitivity analyses for both the convective heat transfer coefficient and mass flow rate. A parametric study for heat storage with materials and bed size is given. A genetic algorithm (GA) is used as a tool to identify the thermal cooling system parameters related to the mathematical model, including the radius of the sphere (rocks), mass flow rate, convective heat transfer coefficient and length of the rock bed. The simulation results have shown an improvement on the performance of the model with identified parameters compared to the performance before parameter optimization. In general, the model with optimal parameters has shown robustness to predict the performance of the cooling system by reducing the input (air) temperature as much as possible at the time when the temperature is hottest.
Transforming African education systems in Science, Technology, Engineering, and Mathematics (STEM) using ICTs: challenges and opportunities
(Education Research International, 2019-02) Barakabitze, Alcardo Alex; Lazaro, Anangisye William Andey; Ainea, Neterindwa; Mkwizu, Michael Hamza; Maziku, Hellen; Matofali, Alex Xavery; Iddi, Aziza; Sanga, Camillius
This paper presents the role of ICTs in transforming Africa’s Education Systems (AES) in science, technology, engineering, and mathematics (STEM) subjects/courses. The paper highlights on a positive shift across Africa in using ICT to improve the quality of teaching and learning through activities such as intensive ICT skills training to teachers, increase in ICT equipments and ap- plications in schools, and emergence of living labs (LLs) and innovation spaces/centres (InnoSpace). We first provide some of the challenges of integrating ICTs in education followed by a description of key past and current ICT initiatives supporting the adoption of ICTs in schools using a number of case studies in sub-Saharan Africa. We further present various ICT-based models for education, as a transformational approach towards integrating ICTs in AES. Moreover, we provide various ICT platforms deployed for education service delivery in disadvantaged African society (e.g., rural areas) including LLs and InnoSpace across the continent. Finally, we highlight our main findings and observations in terms of opportunities and future ICT for education research directions in Africa. Our aim is to provide some guidelines and ensure that Africa uniformly meet the 2030 United Nations Sustainable Development Goal number 4, which is to ensure inclusive and quality education for all and promote lifelong learning, particularly using ICTs.