Browsing by Author "Amanuel, Tesfaye"

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    Determinants of Foreign Direct investment in Ethiopia: An Autoregressive Distributed Lag Approach
    (A.A.U., 2019-11) Amanuel, Tesfaye; Lakew, Alemu (PhD)
    This paper attempts to study the determinant of FDI in Ethiopia for the time period from 1980-2015. To this end, the study has reviewed theoretical explanations relating to the determinants of foreign direct investment and the study has also reviewed relevant empirical literatures focusing on the determinants of FDI in the context of developing countries. Using Data on foreign direct investment and number of telephone users that is obtained from United Nations Conference on Trade and Development (UNCTAD). Real effective exchange rate, inflation rate, export and import data were obtained from National Bank of Ethiopia (NBE), and Ethiopia Real GDP from Ministry of Finance and Economic Development (MoFED). By adopting model that was used by Erdal Demirhan etal (2008) this paper examine prominent determinants of FDI and finds that economic growth, macroeconomic stability, openness to trade are important determinants of foreign direct investment. The results suggest policy makers should give due attention to promoting liberalization and implementing sound economic policies that can ensure macroeconomic stability in the country.
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    Structural Modelling and Analysis of Double Circuit Lattice Power Transmission Tower Subjected to Blast Load
    (Addis Ababa University, 2020-06) Amanuel, Tesfaye; Shifferaw, Taye (PhD)
    A study on the effects of blast loads on tower-line coupling, single tower structure and tower-line structure system has been conducted and a variety of structural response variables have been compared. Time history analysis has been carried out by considering different charge blast parameters and stand-off distances. Various combinations of charge weights and stand-off distances have been considered both on coupled- and uncoupled tower arrangements along with detailed study of the effects of conductor coupling during the analysis modeling and subsequent design of transmission towers. The modular and powerful finite element analysis software Dlubal-RFEM has been utilized for the blast-oriented linear implicit dynamic analysis of latticed transmission line structures covered in this study. The transient dynamic equilibrium equations of the tower have been directly solved by Newmark time integration method. The various internal forces, displacements and a variety of dynamic response behaviors have been isolated, recorded and compared for a single tower and tower-line coupled systems under different charge weight and stand-off scenarios. When numerically modeling and analyzing the structure, both coupled and uncoupled tower-line arrangements, three-dimensional natural vibration analysis has been taken into account. Findings from numerical experiences on several analysis models have indicated that the tower-line coupling system significantly influences the response of tower structures with particular significance on tower supports. Current design codes and guidelines have few, if any, methods or recommendations to deal with power transmission towers subjected to blast loads and, when they do exist, they do not comprehend corresponding tower-line coupled effects. The study has indicated that internal forces in members of uncoupled towers are generally larger than the corresponding values in coupled systems. The main difference arises in the support reactions. Several study models from this work have indicated that there is up to nearly four-fold increase in support forces in uncoupled systems which subsequently greatly influence the planning, selection, design and detailing of support systems for such structures. Thus, the study has revealed the fact that establishing support forces by considering a single uncoupled tower will lead to underestimating critical loads. When designing such structures, coupling effects should be incorporated in the analysis process.