Browsing by Author "Henok Girma"

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    Experimental Analysis of Biogas Production from Seven Types of Feedstocks (Mown Grass, Food Waste, Chicken Manure, Cattle Blood, Cattle Rumen Content, Pig Manure, and Cow Dung)
    (Addis Ababa University, 2023-07) Henok Girma; Ebrahim Tilahun (PhD)
    The significance and role of biogas in energy production and waste management are growing fast. The most determining factor for the gas composition and microorganism community in biogas production is the type of feedstock used. Biomass such as agricultural residues and livestock wastes are the major feedstocks for producing biogas. Ethiopia is one of the leading potential sources of agricultural and livestock wastes in Africa. Regardless of these resources, the majority of Ethiopians still lack access to clean energy. The feedstocks in most domestic biogas digesters constructed by the national biogas program of Ethiopia were mostly livestock (cattle) wastes. This study was conducted to assess the biogas potential of seven feedstocks that were as mown grass, food waste, chicken manure, cattle blood, cattle rumen content, pig manure, and cow dung under a controlled temperature of 40 ± 0.2 in a 500-mL laboratory scale batch digester. The feedstocks used in this experiment were subjected to characterization before and after digestion and the methane production was measured and normalized on a volatile solids basis. The maximum specific methane yield (mL/g VS) and methane percentages of the mown grass, food waste, chicken manure, cattle blood, cattle rumen content, pig manure, and cow dung were 231 and 79.4%, 82.12 and 67.9%, 177.99 and 77.8%, 173.06 and 68.6%, 350.3 and 77.1%, 127.05 and 77.6%, 32.88 and 69.9%, respectively. The chicken manure and cattle blood had the highest concentrations of hydrogen sulfide, producing 1249 and 1102 ppm, respectively. The grass, food waste and inoculum I also generated 805, 170, and 52 ppm of H2S within 28 days of the HRT. The obtained results showed that utilizing feedstocks beside cow dung could increase the quality and quantity of biogas production.
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    The Role of Leadership on Innovation in the case of Ethiopian Airline Group
    (Addis Ababa University, 2023-06) Henok Girma; Solomon Markos (PhD)
    This study is aimed at examining the role of leadership on Innovation at Ethiopian Airlines Group. To achieve this objective, the study adopted a descriptive type of research design. The research was quantitative research. The research is carried out with questionnaire adopted MLQ and Holm and Sjolander (2015) to measure leadership and innovation respectively. Correlation analysis was used to test for the association among the dependent variables and independent variables for the study. The research was quantitative research. From the total population of 355 employees, the sample of 260 respondents were selected using Yemane (1967) sample size determination formula. A structured online questionnaire was used to collect the data. Correlation analysis was used to test for the association among the dependent variables and independent variables for the study. Results of correlation analysis showed that transformational and transactional leadership style had a significant and positive impact on innovation. Correlation analysis also showed that laissez-faire leadership style has a significant negative impact on innovation. Autocratic leadership was found to have an insignificant negative relationship with innovation. The researcher concluded transformational, transactional and laissez- faire leadership styles had a significant impact on innovation whereas autocratic leadership had insignificant impact on innovation. The researcher recommended the organization develop processes and introduce training that promotes transformational and transactional leadership styles while discouraging the laissez-faire and autocratic leadership styles. Thereafter, regression analysis was used to test for the effect of the independent variable of the leadership on the dependent variable (innovation). The results were presented in form of tables and figures with brief descriptions