Browsing by Author "Ali, Hassen"

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    Pastoralists and Agro-Pastoralists Vulnerability to Climate change and Adaptation Response: The Case of Aysaita Woreda, Afar Regional State, Northern Ethiopia
    (Addis Ababa University, 2017-06) Ali, Hassen; G/Michael, Yohannes (PhD)
    This study was conducted in Aysaita woreda, Afar Regional State of Ethiopia with the objective assessing pastoralists ad agro pastoralists vulnerability to climate change and adaptation response in Aysaita woreda. The study was conducted in two rural kebeles of Galifage and Barga kebele. purposive sampling was used to select the study area and stratified sampling were also used by categorizing agro ecology and wealth status group. After strata simple random sampling was used to select 153 respondents in the study areas. In addition, 1 FGD in each kebele were made which have 7 members in the group comprising the elderly people men and women, rich people men and women, medium people men and women, poor men and women, model farmers and adult. The data were collected from primary data were selected from interview, FGD, observation, while secondary data were selected from project report and information at woreda level The key informant interview with resourceful 50 farmers and 4 development agent persons were conducted. The key informant interview included experienced people and community elders, including men and women also included woreda experts and kebele leaders. Suitable word and descriptive statistics were employed to analyze the data. The result shows according to participant in the study area most of pastoral and agro pastoralist community perceived as temperature increased and decreased rainfall in their locality. The pastoralist in the study area is vulnerable and the cause of vulnerability in the study area like; drought, flood, shortage of water, governmental intervention. And this has led pastoralist to adverse impacts on the study area like: human and livestock loss, prosopis juliflora, deforestation, environmental degradation and famine, migration were the major impact in the study areas. Different local adaptation and coping mechanism like; mobility, fodder management, diversifying livestock and crops, selling of fuel wood and charcoal, change meal size, sharing risk, polygamy marriage, Handicrafts activities were used. hinders to do not make them their coping mechanism thus; limited access, lack of agricultural input support from GOs and NGOs, limited access and poverty are the major hinder in the study area. Based on the findings the following recommendations are forwarded: developing farmers’ awareness on how to managed their natural resources, introduce agricultural technologies & inputs, facilitating access to credit services, diversifying source of income, set backing of prosopis juliflora expansion, empowering women, controlling of Awash river. Key word: Climate Change, Vulnerability, Impact, Adaptation, Coping strategies
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    Simulation and Modeling Modeling of Syngas Production via Glycerol Dry Reforming Using Aspen plus
    (Addis Ababa University, 2018-11) Ali, Hassen; Hundessa, Dessalegn (PhD)
    The surfeit of crude glycerol as by product from biodiesel industry triggered alternative routes to valorise glycerol to value added fuels such as syngas, mixture of hydrogen and carbon monoxide. Dry reforming of glycerol uses carbon dioxide (CO2) as reactant to produce syngas. The process of glycerol dry reforming has been simulated and the effect of thermodynamic properties on yield, selectivity and conversion were studied and optimized with the aid of ASPEN PLUS V8.8 in this paper. The process of simulating glycerol dry reforming was carried out using RGIBBS and RPLUG reactor types. The sensitivity analysis and the optimization of the process were accomplished using the sensitivity and optimization sections of the model analysis tools of the ASPEN PLUS. Furthermore, sensitivity analysis was carried out to observe the effect of several parameters. The kinetic data for glycerol dry reforming and water gas shift reactions were obtained from literature. The kinetic based simulation was performed using ASPEN PLUS RPLUG model blocks with rearranged Power law and Langmuir-Hinshelwood-Hougen –Watson (LHHW). The result obtained revealed that the simulation with RGIBBS and RPLUG gave different values of components. Furthermore, it was revealed from sensitivity analysis of the process that optimization was necessary to obtain the operating variable that would involved in the process. Optimization was able to give a satisfactory value of conversion of glycerol, carbon dioxide for reforming and carbon monoxide and water for water gas shift reaction. However, much has been reported about thermodynamic analysis of steam reforming of glycerol, little is known about thermodynamic analysis of glycerol dry reforming. In this regard, in the current work, with Aspen plus simulator glycerol dry reforming thermodynamic analysis is carried out. The effect of process such as: temperature, pressure, length of the reactor, catalyst particle density, and feed ratio to the reactor performance were investigated. Based on this the yield of syngas was 92% over the range of temperature 573 -1273K whereas, over the range of pressure 1-30 bar and feed ratio 1-5; the yield of syngas were 50% and 51.24% respectively