Abyssinia Journal of Engineering and Computing

Development of Potential Woven Fabric Designs with Existing Loom-Set up

Neway Seboka — 2024-11-20

Weaving factories in Ethiopia are sticking to limited types of product categories. It is analyzed that production of bed-sheeting and sheeting material covers more than 50% of the total product varieties. Besides, production of shirting, blankets & suiting in total covers only about 40%. Due to this, demands for basic product categories of shirting, suiting, dress materials, curtains and towels are not fulfilled with local factories product mix. Thus, the country is forced to import such products from different countries like: China, Italy, Turkey, India, Netherlands, United States, Taiwan, etc. for assessing the majorly imported product mix, three month import data has been taken from Ethiopian customs revenue authority and analyzed that for this 3-month period, a total cost of USD 566,329 has been withdrawn for purchasing the products. So, this paper tries to assess the machinery and loom conditions of the selected representative factories with main parameters of shedding mechanisms, make & model of the looms and active/working number of harness frames. Shedding contributes about 50%, 40% & 10% for tappet, dobby and jacquard mechanisms respectively & the number of harness frames in the looms ranges from 6 to 20 for both tappet and dobby looms respectively. Accordingly, with this machine set-up the potential woven fabric designs, which have application areas of shirting, dresses, suiting, towels & home furnishings have been studied in detail and more than 15 product designs have been suggested with details of required heald shafts, drafting procedures, lifting plans and specific application areas.

Impact of Land Use Land Cover Dynamics on Stream Flow: A case of Borkena Watershed, Awash Basin, Ethiopia

Metafet Asmare Abebe — 2024-11-20

Land use and land cover in recent decades have changed ecosystems more rapidly and extensively than in any comparable period. Land used land cover (LULC) change is one of the major factors that affect the watershed response. The LULC change analysis was performed by using supervised classification method in ENVI software. The study results showed that the watershed experienced significant LULC change from 1986 to 2016. During the study period, most parts of the grass land, cultivation land, and shrub land were changed to build- up area and bare Land. The LULC map shows an increase of buildup area and bare Land by 3.6% and 5.9% respectively over the last 31 years. The SWAT model was used to assess the impact of LULC change on stream flow for the period 1996 to 2016. The result showed that there was a good agreement between observed and simulated stream flow with a coefficient of determination (R² ) and NashSutcliff efficiency (N_ef) values of 0.81 and 0.79 for calibration, and 0.75 and 0.74 for validation periods, respectively. The evaluation of the SWAT hydrologic response unit (HRU) due to LULC change between the years 1996 and 2016 showed that monthly stream flow was increased by 5.4 m³/s in wet season and decreased by 0.5 m³/s in dry season from 1996 to 2016. Understanding the effect of LULC change on stream flow is crucial for knowledge-based decision making in the development of water resources projects.

Effects of Anaerobic Co-digestion of Cow Dung using Biodegradable Municipal Wastes for Biogas Production

Teklie Lissanu — 2024-11-20

Biogas is a renewable energy resource produced by anaerobic digestion (AD). Biogas production trough anaerobic digestion was found to be unstable when the cattle manure is used as mono substrate due to the low carbon to nitrogen ratio. The aim of this research is to extract biogas by anaerobic-digestion technique using cow dung (CD) and municipal solid waste (MSW) at different proportions. It was carried out by 15, 0.5 L digesters at 38 °C using oven atmesophilic condition. Samples were analysed for its total solids (TS), volatile solids (VS), fixed solids, organic carbon, moisture content, and potential of hydrogen (pH) according to standard method for the examination of water and wastewater. Biogas yield was recorded by using volume displacement method. Maximum cumulative biogas production by the substrate mixes of 0 % MSW+100 % CD (2818.3 ml) and a maximum daily biogas production for 75% CD+25% MSW (620 ml) with minimum of 0 ml for all substrate mix at end of day 22. Cumulative biogas yield of 100% CD digestion was found to be better yielding. It is also observed that, co-digestion of MSW with cow dung does not increase the amount of biogas production over only with 100 % CD. However, cow dung added with MSW has enhanced the amount of biogas yield and reduction in percentage of VS and TS as compared to 100 % MSW.

Optimal Operation of Cascade Reservoir Systems under Climate Change: Case Study of Tekeze Hydropower Reservoir in the Tributary of the Blue Nile River

Fikru F. Abera — 2024-11-20

Planning and optimal operation of reservoirs under the paradigm of climate change is one of the most momentous problems in the planning and management of water resources due to the rapid growth of economy and population. In this study, Soil and Water Assessment Tool (SWAT) and reservoir operation optimization (HEC-ResPRM) models have been employed in the three cascade hydropower reservoirs in Tekeze basin, Ethiopia to investigate the impact of planned cascade reservoirs’ operation on the existing reservoir on the face of climate change. Results showed that an increase in rainfall and temperature in the future will be critical to future inflow in cascade hydropower reservoirs, with rainfall variability having a greater impact than temperature variability. HEC-ResPRM was prepared to reproduce optimum hydropower reservoir storage and water levels on the joint cascade operation of Tekeze reservoirs in each mode under climate change effect. Joint optimum operation of cascade reservoirs in different operation modes under climate change in both RCP4.5 and RCP8.5 climate scenarios affects existing reservoir operation in the future. Therefore, it is better to improve existing reservoir operation before investing into new planned cascade reservoirs and incorporate climate change scenarios in the planning, design, and operation of new reservoirs in Tekeze Basin. The results of this study can help the water resources planners and managers to plan and manage the future water resources of Ethiopian Rivers.

Ethiopian Sisal fiber and Unsaturated Polyester Composite Panel Fabrication to Characterize Flexural Properties for Future Opportunities in Car Body Applications

Hailay Kidane — 2024-11-20

Ethiopian Sisal fibers were extracted manually and treated with alkali to enhance fiber and matrix adhesion. Sisal fibre reinforced unsaturated polyester composites were devolved by hand lay-up techniques. Sisal fibers bundle strength has been tested by pressley strength tester machine. Average bundle strength of the fiber was 67.12g/ tex. The fibers maturity % was 15.82. Sisal fibers have been oriented by using mini card machine, where it's aligned in parallel way and stitched by using conventional sewing machine. The sisal fiber reinforced unsaturated polyester composites have been made with different ply arrangements such as unidirectional arrangement (0^o 4), (90^o 4), and cross ply orientations (0^o /90^o ) s. All the test samples were prepared as per the ASTM standards. The experimental results showed that the flexural strength of 57/43 % by volume ratio of sisal fiber reinforced polymer composites with axial directional arrangement (0^o 4) gives better results, which is 37 N/mm2 . Sisal reinforced unsaturated polyester resin composite shows better mechanical properties applicable for car body applications.