Browsing by Author "Abdulkadir, Mohammed"

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    Assessment of Earthquake Analysis Methods of Intake Towers
    (Addis Ababa University, 2011-10) Abdulkadir, Mohammed; Zekaria, Adil (PhD)
    Seismic analysis of an intake tower may be carried out using one or more methods from the methods Seismic Coefficient (SCM), Equivalent Lateral Force (ELFM), Response Spectrum (RSM) and Modal-Time history (MTHM) Methods. SCM, ELFM or RSM may produce response quantities with magnitudes bigger or smaller than those of refined method (MTHM). How big or small are the magnitudes in comparison with those of the refined method? In other words, are the magnitudes of SCM, ELFM or RSM overestimated or underestimated when contrasted with those of the refined method (MTHM)? Answering these questions through detail investigation is the core objective of this study. In order to meet the core objective, an investigation of the seismic analysis methods of intake towers was conducted. The investigation was conducted by performing elastic seismic analysis of a squat free-standing intake tower, using the conventional and refined methods; and comparing the results of the analysis. The investigation started by selecting a suitable intake tower and its location for the study. In this regard, the squat free standing intake tower in kesem Dam irrigation project, in Afar Regional State, was found to be suitable. The project is located in East African Rift Valley which is largely prone to earthquake excitations. After selecting the intake tower and its location, the next step was structural, material and hydrodynamic modeling. Following the modeling, in put ground motions in form of response spectra and ground acceleration time-histories were developed. Next, seismic analysis of the intake tower was carried out using the models and the input ground motions; and applying each of the methods at a time. Finally, the results of the analysis were examined. From the examination, the study concluded that the magnitude of response quantities computed with SCM, ELFM or RSM were significantly different from those of the refined method. Moreover, the study concluded that the magnitudes of the response quantities computed with three methods were underestimated. So, SCM, ELFM or RSM, especially SCM, are inappropriate for detail seismic analysis of squat free-standing intake towers. As result, the study decided that MTHM shall be used for final and detail elastic seismic analysis of free-standing squat intake towers. However, further investigation are required in order to extend vi the conclusion to other classes of intake tower such as free-standing slender intake towers and inclined intake towers. Similarly, other investigations are desirable in order to extend the conclusions of this study to inelastic analysis methods of intake tower.
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    SEROPREVALENCE OF BRUCELLOSIS IN LIVESTOCK AND HUMAN IN ASAYITA AND MILLE DISTRICTS OF AFAR REGION, ETHIOPIA
    (2019-06) Abdulkadir, Mohammed; Dr. Gezahegn Mamo, Dr. Rea Tshopp
    Brucellosis is one of the neglected infectious zoonotic diseaseswith a serious public health importance worldwide. In pastoralist communities of Ethiopia, brucellosis is a major public health problem and has serious economic impact on livestock sectors. A cross-sectional study was conducted from November 2017 to April 2018 in one-health approach to estimate he sero prevalence and associated risk factors of brucellosis in livestock (cattle, camel, sheep and goats) and human in Mille and Asayita districts, Afar Region. A total of 562 livestock (goats, sheep, cattle and camel) and 172 human sera from pastoralists who own these livestock were tested using indirect/competitive ELISA. Based on the result, the overall seroprevalence of brucellosis in livestock (small ruminants, cattle and camel) was 9.07% [95% CI=6.6-11.45]. The highest seroprevalence was recorded in cattle 16.67% [95%CI:9.3-24] while the lowest seroprevalence was observed in camels 3.7% [95%CI: 0.4-7.9]. The differences in sero positivity between livestock species in study area were statistically significant (p=0.014). Other risk factors (districts and sex) did not show a statistically significant difference between the categories (p>0.05). On the other hand, the overall sero prevalence of human brucellosis in the pastoralist livestock owner was 48.8% [95%CI: 41.2- 56.3] using indirect ELISA test. Higher human brucellosis sero prevalence was recorded in Mille district (63.1%) than Asayita (35.2%).