Browsing by Author "Getachew Gizaw"

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    A Computational Investigation of Hydrated Magnesium Sulfate Clusters and their FAU Composites for Improved Thermochemical Energy Storage
    (Addis Ababa University, 2024-06) Belaynew Teshome; Getachew Gizaw; Ahmed Mustefa
    The effective use of renewable energy sources and the decrease of greenhouse gas emissions are greatly dependent on thermal energy storage, or TES. We report a computational method for examining the hydrate clusters of hydrated magnesium sulfate (MgSO4) and their compounds with faujasite zeolite (FAU) for enhanced performance in thermoelectric sensing (TES). The optimal hydration states and structural characteristics of the hydrated MgSO4 clusters were revealed through modeling with density functional theory (DFT) calculations. Molecular dynamics techniques were used for optimization of composite structure implemented by Vienna Ab initio Simulation Package (VASP) software. After this, the TES capacity, reversibility, and thermal conductivity of the MgSO4 hydrate-FAU composites were assessed. As a result of their superior heat storage properties over their constituent parts, composite materials are a strong contender for advanced thermal energy storage applications, according to the research. This method of computational research gives a logical way to create high-performance thermoelectric solar materials while also shedding light on the interactions at the molecular level.
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    Compatibility of Design and Practice of Postgraduate Evening Extension Program with Needs and Developmental Profiles of Adult Learners: The Case of College Of Education and Behavioral Studies, AAU
    (Addis Ababa University, 2018-06) Getachew Gizaw; Belay Tefera
    This study attempts to investigate the compatibility of the design and practice of postgraduate evening extension program with needs and developmental profiles of adult learners. To achieve this objective, both qualitative and quantitative study design was employed. The samples were selected using incidental sampling methods. The respondents were 112, 108 rates evening extension program graduate students from CEBS and four instructors from college of education behavioral science, purposefully selected . The data was collected through interview and questionnaire, structured interview guide were designed to gather qualitative and quantitative data from the participants of the research. The data were analyzed and discussed in description analysis method. The finding of the study should that there was compatibility in content, goal and organization of postgraduate education with adult needs and developmental profiles. In contrast Methods and assessment of postgraduate education with adult needs and developmental profiles were not compatible. The findings of the study revealed the college of education and behavioral studies and Addis Ababa University; the study suggest that the curriculum needs to be designed for evening extension program based on he needs and developmental profiles of adult learners and applying the right method of teaching and the targeted assessment
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    Computational Investigation of Ca(OH)2 / CaO for Thermochemical Energy Storage
    (Addis Ababa University, 2024-06) Sada Husen; Getachew Gizaw
    Thermochemical energy storage (TCES) systems are essential for improving the efficiency and reliability of renewable energy technologies. Calcium hydroxide (Ca(OH)₂) and calcium oxide (CaO) are promising candidates for TCES due to their high energy density and reversible hydration-dehydration reactions. This study presents a comprehensive computational investigation of Li and Li₂-doped Ca(OH)₂/CaO clusters using the Vienna Ab initio Simulation Package (VASP) and ABCluster software. Clusters of Ca(OH)₂ and CaO with sizes ranging from n=1 to n=10 was prepared, and low-lying isomers were selected for detailed analysis. Density Functional Theory (DFT) calculations were conducted to optimize the geometries and compute binding energy, formation energy, and second-order energy corrections. It is evident from the stability analysis that the doped clusters' average binding energies and formation energies are higher than those of the comparable pure Ca(OH)n and (CaO) clusters. Maximum peaks of the second order energy differences are seen for LiCan−1(OH)n (n=2−10), Li2Can−1(OH)n (n=2−10) and LiCan-1On (n=2-10), Li2Can-1On (n=2-10) clusters at n=6, 4, and 2 suggesting that these clusters are more stable than the clusters that are surrounding them. Clusters with n=6 were specifically chosen for evaluating energy storage potential. Additionally, dehydration curves were plotted to assess the energy release characteristics. The results demonstrate that Li and Li₂ doping significantly enhances the thermochemical properties of Ca(OH)₂/CaO clusters, resulting in higher energy storage density, improved reaction kinetics, and better cycling stability.