Browsing by Author "Getahun Kebede"

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    Enhancing Railway Infrastructure Protection through System Dynamics Modeling and Analysis: A Case of the Ethio-Djibouti Railway
    (Addis Ababa University, 2024-06) Getahun Kebede; Birhanu Beshah (PhD); Mulatu Tilahun (Mr.) Co-Advisor
    The railway infrastructure in Ethiopia faces significant threats from natural disasters, human-made destruction, and technical failures. Reports indicate a concerning trend of frequent theft and vandalism incidents targeting critical railway components, which disrupt service, compromise safety, and incur substantial financial losses. This study aims to develop a comprehensive system dynamics model to identify the risks and challenges associated with protecting the Ethio-Djibouti Railway (EDR) infrastructure and propose effective mitigation strategies. The research employs a mixed-methods approach, combining qualitative and quantitative data gathered through expert interviews, questioners and literature review. A system dynamics model is constructed to capture the key variables and their interrelationships affecting railway infrastructure protection. The model is used to simulate different scenarios and test the effectiveness of interventions. The findings reveal that the selected Exogenous variables “community empowerment and awareness creation, accidents on domestic animals, and population density” have a great impact on the entire infrastructure security. Those variables are found to be effective in minimizing accidents, train delay time and blockages, and overall infrastructure damage. The study also highlights the impact of population density, where highly populated areas tend to experience increased theft and vandalism, leading to more train delays. In Addition to that this research also recommended and showed in the system dynamics model, Implementing various surveillance mechanisms, such as technology-enabled monitoring, can significantly reduce the incidents of theft and vandalism. By integrating Crime Prevention Through Environmental Design (CPTED) principles with system dynamics modeling, this research provides a holistic framework for improving the overall safety and security of the EDR infrastructure. The study's recommendations serve as a valuable resource for future studies, policymakers and railway operators to develop and implement targeted interventions to safeguard railway infrastructure.
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    Sugarcane Byproducts as Feed Resources and Performance of Sheep Fed on Sugarcane Tops Based Diets
    (2019-08) Getahun Kebede; Ashenafi Mengistu
    Enhanced feed use of sugarcane byproducts is imperative to improve livestock productivity and reduce production cost in Ethiopia. Four successive studies were conducted. The production and utilization of sugarcane byproducts in Wonji-Shoa and Metehara Sugar Estates were assessed by interviewing farm households (n, 308) and collecting secondary data. Green and burnt sugarcane tops (SCT) (variety N-14) were conserved as silage and hay and evaluated for quality. The green and burnt SCT were ensiled with or without 4% molasses, 1% urea and 1% urea + 4% molasses in mini-silos for 45 days. In the hay experiment, the green and burnt SCT were dried (15% moisture) by applying three drying methods (shed and sun-drying of intact SCT and sun-drying of chopped SCT). An experiment was also conducted to evaluate performances of Arsi-Bale lambs consumed diets based on burnt SCT silage or hay, replacing natural pasture hay at 0, 33 and 67% (on dry matter (DM) basis) and concentrate supplementation (317 g DM/day). Farm households using SCT as feed were high (Wonji-Shoa-100%; Metehara- 100%), moderate for molasses (53; 0.9%) and negligible for bagasse (0; 1.8%). The total production volume (on wet bases) of sugarcane byproducts was in the order of bagasse>SCT>molasses and generally higher in Metehara than in Wonji-Shoa. Availability and feed use share of the burnt SCT surpassed green SCT, which coincided with the critical feed shortage period. The prices of the burnt and green SCT in Metehara (297.86 and 195.5 Birr/cart) were three-fold more than in Wonji-Shoa (P<0.001). Farmers preferred the burnt to green and thin- to thick-stem SCT varieties. Sugarcane tops were mainly preserved by sun-drying (Metehara-98.2%; Wonji-Shoa- 80.8%) and stored in open-air (91.8%; 85.9%). Limitations in the feed use of sugarcane byproducts included: low quality of SCT (91.2%), health risks such as mouth injury or toxicity associated with feeding SCT (16.2%) or molasses (74.7%) lack of labour/capital (11.7%), lack of transport (26%), lack of molasses suppliers (85.1%) and lack of technical supports (89%). The best SCT silage physical properties were attained by ensiling alone or with 4% molasses. The pH of silages ranged 3.7-5.0, except in the green SCT ensiled with urea based additives (pH>5). Total DM loss (2.31%) and temperature (26˚C) were low (P<0.0319) in the green SCT ensiled with molasses alone. Urea addition increased (P<0.0001) silage crude protein (CP). The fiber fractions of burnt SCT silage were not affected (P>0.05) by the additives, while neutral detergent fiber (NDF) increased by 17.5% with urea inclusion and acid detergent fiber (ADF) decreased by 15.6% with molasses addition in green SCT silage. In vitro organic matter digestibility and metabolizable energy (ME) were peaked (P<0.0001) in the burnt SCT ensiled with 1% urea + 4% molasses. The lowest (P<0.0001) non-fiber carbohydrate (NFC) was observed in the green SCT ensiled with urea based additives. The chopped sun-dried SCT had the highest dehydration rate (20.3%/day) and dried in three days, while shed-dried intact SCT had the lowest drying rate (0.96%/day) taking more time to dry (green, 68; burnt, 60 days). The DM and CP contents were not affected (P>0.05) by the drying methods. The sun-dried chopped green and burnt SCT did not differ (P>0.05) in DM digestibility and ME content and had the highest (P<0.0001) ether extract (EE) and hemicelluloses. The DM intake of lambs was lower (P<0.05) at higher (67%) silage offer, but not affected by the SCT hay. The lowest (P<0.0001) intake of CP was at higher SCT hay offer, while for the fiber fractions at higher silage offer (P<0.05). Treatments did not vary (P>0.05) in DM digestibility, lambs’ growth performances, feed conversion efficiency, carcass characteristics, and meat chemical composition and cooking loss. The overall average final body weight, total gain, daily gain (ADG) and feed conversion efficiency (FCE) were 27.21 kg, 7.85 kg, 87.22 g and 0.110, respectively. In conclusion, the provision of technical support to farmers on processing, conservation, feeding management and marketing and distribution of sugarcane byproducts is important. Conservation of SCT is more effective by chopping and sun-drying, and by ensiling alone or with 4% molasses in green SCT, and with 1% urea and 4% molasses solution in burnt SCT. Moreover, SCT silage or hay can replace up to 67% of natural pasture hay for yearling Arsi-Bale lambs at an economic benefit.