Mechanical and Industrial Engineering
Permanent URI for this collectionhttps://repository.mu.edu.et/handle/123456789/522
Browse
37 results
Search Results
Item Simulation-Based Investigation of Adaptive Suspension Control for Regional Road Conditions in Tigray(Mekelle University, 2025-11-19) Abraha GebruThis thesis presents the design, modeling, simulation, and performance evaluation of an adaptive suspension control system developed to improve vehicle dynamics under the diverse road conditions of the Tigray region, Ethiopia. Suspension systems are fundamental in enhancing ride comfort, handling, and overall vehicle stability. Conventional passive suspensions, while simple and cost-effective, lack adaptability to the rapidly changing and uneven road conditions prevalent in developing regions. In response, researchers have introduced various intelligent control techniques—such as PID, Fuzzy Logic, and Adaptive Neuro-Fuzzy Inference Systems (ANFIS)—to address these challenges. However, existing studies still face limitations in real-time adaptability, nonlinear response management, and system robustness across unpredictable terrains. To overcome these challenges, this study proposes a hybrid PID–ANFIS adaptive suspension control approach, combining the fast response of the PID controller with the learning and adaptability of ANFIS. A quarter-car model of a light-duty vehicle was developed in MATLAB/Simulink to simulate various representative road conditions, including paved, unpaved, bump, and hilly terrains. The controller’s performance was evaluated using key dynamic metrics: ride comfort (weighted RMS acceleration), suspension travel, and road holding ability. Simulation results demonstrated that the hybrid PID–ANFIS controller outperformed both the classical PID and passive suspension systems. Specifically, body acceleration was reduced by over 80%, suspension travel was maintained within safe mechanical limits, and tire force variation was minimized, improving road holding stability. The overshoot decreased from 72.33% (PID) to 19.73% (PID–ANFIS), while rise time improved from 34.71 ms to 12.59 ms, and the RMS error reduced from 0.05784 (passive) to 0.00026 (PID–ANFIS). Compared to prior studies reporting 70–78% improvement using hybrid controllers, the proposed system achieved higher performance gains due to optimized parameter tuning and adaptive learning capabilities. The results confirm that the proposed hybrid PID–ANFIS controller is an effective, terrain-adaptive solution capable of improving ride comfort, stability, and safety for vehicles operating in challenging regional road conditions. This work contributes a region-specific adaptive suspension model that can be applied to improve vehicle performance in developing areas with similar infrastructure characteristics.Item Modeling, Simulation, and Experimental Validation of an Electrical-based Injera Baking Mitad System(Mekelle University, 2025-08-14) Ataklti GedamuAbout 30 to 50 percent of Ethiopian households utilize energy for injera baking, and conventional charcoal-fired Mitads produce a lot of emissions (about 1.2 kg CO₂ per session). Although they provide an alternative, electric mitads have a thermal efficiency that is typically between 60 and 70 percent. By using numerical modeling of composite materials to optimize electric Mitad performance, this study fills a research void that hasn't been filled by previous experimental work. We verified 17 minutes to reach 148°C and baked 21 injeras at 3 minutes each (66.81% efficiency) using ANSYS transient thermal software to validate a baseline model (2.8 kW clay pan) against experimental data (<3% deviance). Three composites were assessed: [1] Heating time was shortened by 59% (7 minutes to 150°C) using 95% clay and 5% aluminum chips. and baking time to 2.5 minutes per injera, achieving 70.21% efficiency (0.47 kWh/session saved); [2] ceramic reached 150°C in 12.5 minutes but required reheating due to ~10°C temperature drops per cycle; [3] 60:40 clay-aluminum composite achieved 150°C in 9 minutes with stable heat retention (68.2% efficiency). The 95% clay-aluminum composite demonstrated 25% total energy reduction per cycle, potentially saving households ~120 kWh annually. This work enables future optimization of composites, insulation, and socioeconomic analysis of production costs versus energy/fuel savings.Item MODELING AND SIMULATION OF A COMPACT ELECTRIC VEHICLE CONVERSION FOR ETHIOPIAN URBAN TRANSPORT USING MATLAB/SIMULINK(Mekelle University, 2025-11-19) HEAVEN AMANUELEthiopia’s transition to sustainable mobility is challenged by high fuel costs, import dependence, and limited access to affordable electric vehicles (EVs). This study develops a technically feasible and economically adaptable framework for converting internal combustion engine (ICE) vehicles to EVs, ensuring compliance with national retrofit standards and optimizing drivetrain integration, energy efficiency, and performance validation. A widely used 1993 Toyota Corolla was selected for conversion and equipped with a three-phase liquid-cooled BLDC motor rated at 20 kW nominal and 50 kW peak power, limited to 145 Nm torque per standard. The 121.6 V, 280 Ah LiFePO₄ battery pack (34.06 kWh) powered the system, while the original five-speed gearbox was retained to enhance torque delivery and maintain compatibility. Safety and auxiliary systems included vacuum-assisted braking, electric hydraulic steering, and a 600 A battery management system. The methodology encompassed powertrain sizing, component selection, and MATLAB/Simulink-based simulations using the FTP-75 urban cycle. Results showed a 261 km range per charge and 130.6 Wh/km energy consumption, indicating strong urban applicability. Compared with commercially available EVs such as the BYD Seagull, the converted vehicle exhibited comparable performance and efficiency. The originality of this work lies in its use of a locally available ICE platform, adherence to Ethiopian retrofit standards, and comprehensive simulation-based validation. These findings highlight the potential of vehicle retrofitting as a cost-effective strategy for electrifying Ethiopia’s existing fleet, reducing fuel dependency, and supporting national sustainability goals.Item DEVELOPMENT AND SELECTION OF GLASS/SISAL AND SHEEP WOOL FIBER REINFORCED HYBRID POLYMER COMPOSITES FOR VEHICLE BUMPERS(Mekelle University, 2025-11-24) Mulu GideyBackground: A bumper is an essential part of a vehicle, engineered to absorb impacts and shield the front and rear during low-speed collisions. This research focuses on creating glass/sisal and sheep wool fiber-reinforced composites for bumpers, meeting the demand for lightweight, sustainable materials while fostering local economic growth through job creation. It seeks to substitute traditional heavy materials, decrease costs, and advance sustainability initiatives within the automotive sector. Objective: The primary objective of this research is to develop and select hybrid composite materials that combine glass, sisal, and wool fibers reinforced with epoxy resin for use in vehicle bumpers. Specific goals include enhancing the mechanical properties of natural fibers and optimizing the composite design for performance and cost-effectiveness. Method: The methodology involves treating sisal and wool fibers with sodium hydroxide to enhance their mechanical properties, followed by the fabrication of composites using hand lay-up techniques. A comprehensive series of mechanical tests based on ASTM standards assesses properties such as tensile strength, impact resistance, and water absorption. Result: The composites demonstrate a tensile strength of 114.07 MPa, impact resistance of 112.5 kJ/m², and the composite bumper can absorb a maximum energy of 49.34kJ/m2 with speed 2.22m/s, and also a weight of 3.8 kg, significantly lighter than traditional steel bumpers (5.16 kg). Software analysis using Genetic Algorithms optimized the design, achieving a maximum stress of 31 Mpa and a deflection of 89 mm under impact conditions, indicating superior performance compared to conventional materials. This study supports the transition to environmentally friendly materials in the automotive industry. Conclusion: This research substantiates that glass/sisal and wool fiber-reinforced composites are viable alternatives for automotive bumper applications, offering improved performance and reduced environmental impact, to reduced fuel consumption and local economic growth. The findings support the ongoing transition toward sustainable materials in the automotive industry and highlight the economic benefits associated with local fiber utilization.Item Feasibility Study and Energy Management System of Mini Grid Hybrid Systems for Energy Intensive Industries: A Case Study of Industries in Mekelle(Mekelle University, 2025-05-30) Hiwot NigusieHybrid systems integrate renewable energy sources with battery storage to supply energy in offgrid or on-grid setups. Many studies on hybrid power generation focus primarily on rural electrification, the socio economic benefits for households and local communities and remote areas, often overlooking the impact on industrial development. This literature gap limits our understanding of how reliable electricity access could drive industrial growth, enhance productivity, and foster economic diversification. This study focused on the techno-economic feasibility of a mini hybrid power generation system for electrification of three energy intensive manufacturing industries that are located in Mekelle city of Tigray namely Mesfin Industrial Engineering, MOHA soft drinks industry, and Desta Alcohol & Liquor Factory. The aim was to study the feasibility of a hybrid renewable energy solution to make industries energy independent and provide sufficient power and tied them with reliable power system by avoiding their grid dependency. The software packages utilized is used to design, analyze, and optimize the hybrid power system were HOMER Pro modeling tool. The mini grid has a peak capacity of 230 kW requires 3005 kWh/day. The Generic PV system has a nominal capacity of 720 kW. The annual production is 1,321,381 kWh per year for Mesfin Industrial Engineering. The electric needs for MOHA soft drinks industry are met with 720 kW of PV, 320 kW of generator capacity, 330 kW of wind generation capacity with operating costs for energy of $388,003 per year without battery storage. An addition of 1,000 kWh of battery capacity is proposed. This will reduce the operating costs to $458,636 per year. A 50 kW of generator capacity, 1,000 kWh of battery capacity and for Desta Alcohol & Liquor Factory 50 kW of wind generation capacity, with operating costs of $154,451 per year. It is proposed that adding 110 kW of hydropower generation capacity would reduce operating costs to $154,421/yr.Item Design and Experimental Evaluation of passive Solar Still under hottest and driest climate condition of Ethiopia: A case of lake-Afdera saline water(Mekelle University, 2024-12-25) Mohammed Ahmed YasinAccess to potable water remains a critical challenge globally, particularly in arid regions such as Ethiopia's Afar Region, where groundwater is often limited or contaminated with high levels of fluoride and salinity. This study investigates the design and performance of passive solar stills for desalinating saline water from Lake Afdera under extreme climatic conditions. The objective was to enhance the productivity of conventional single-slope, single-basin solar stills by incorporating black volcanic rocks as thermal energy-absorbing materials. Two solar still configurations a conventional design and a modified design with black volcanic rocks were constructed and experimentally evaluated over two days in Afdera. Parameters such as ambient temperature, water temperature, and hourly yield were recorded. To validate the results, the modified still was later tested under different environmental conditions at Mekelle University using thermocouples, PicoLog software, a pyranometer, and measuring jars for precise data collection. Results showed that the modified solar still significantly outperformed the conventional still in water yield, producing 3,482 ml and 3,800 ml over two days compared to 1,920 ml and 1,780 ml, respectively. It also demonstrated improved night-time performance, yielding 890 ml versus 340ml, due to better heat retention from the black rocks. Correlation analysis from the Mekelle validation indicated strong relationships between water yield and solar radiation (r = 0.60), rock temperature (r = 0.96), internal temperature (r = 0.85), and ambient temperature (r = 0.83). The modified system achieved 32.87% higher efficiency in Afdera than in Mekelle, highlighting the role of environmental conditions. The findings confirm that integrating black volcanic rocks into solar still design enhances efficiency and output, offering a cost-effective and sustainable desalination solution for arid, high radiation regions like Afar.Item Feasibility Study of Integrated Hybrid Energy System for off-Grid Rural Electrification: Case of Three Village(Mekelle University, 2024-09-28) Yeshareg YrgalemThis research presents a feasibility study of an integrated hybrid energy system designed for off grid rural electrification in three villages in Ethiopia's Tigray region. With over 56% of Ethiopia's population lacking access to electricity, the National Electrification Program (NEP) aims to achieve universal electricity access by 2025, promoting a mix of grid and off-grid solutions. This study explores the potential of combining wind, solar, and biogas to create a sustainable energy model that aligns with the NEP's objectives. The objectives of this study are threefold: to assess the renewable energy resources available in the selected villages, to design and size the components of a hybrid energy system, and to evaluate the technical and economic feasibility of the proposed solution. The methodology involves data collection through site assessments, resource evaluations, load estimations, and modeling using the HOMER Pro software. The study evaluates the energy demands of Felege Mayat, May Shih, and Mayderhu villages, revealing daily energy requirements of 1673 kWh, 1215 kWh, and 785 kWh, respectively. The findings indicate that a hybrid system—combining wind, solar, and biogas—can deliver a sustainable, reliable, and cost-effective electricity supply, with levelized costs of electricity (COE) at $0.0139/kWh, $0.0158/kWh, and $0.0167/kWh for each village. This approach not only addresses the immediate energy needs in these rural communities but also promotes environmental sustainability by reducing dependence on traditional biomass. In conclusion, this thesis highlights the potential of integrated hybrid energy systems to bridge the energy gap in rural Ethiopia, promoting sustainable development and improving human wellbeing. Recommendations for future research and implementation strategies are provided to facilitate the adoption of such systems in similar contexts.Item Experimental Study on the Effect of Operating Parameters on Hydrogen Production from Alkaline Wastewater Electrolysis(Mekelle University, 2024-12-28) Yibrah GebrecherkosThis study investigated the influence of three principal operating parameters on hydrogen production from alkaline wastewater electrolysis. Hence the primary objective of this study was to examine the effects of specific operating conditions on hydrogen yield, employing alkaline wastewater as electrolyte. The key parameters examined included temperature variation, effect of electrolyte concentration variation, and applied current variability. The findings indicated that electrolysis performance was significantly influenced by these parameters. Specifically, the volume of hydrogen produced rose with rising current. At the tested currents of 0.3A, 0.5A, 0.7A, and 0.8A, the time needed to reach 10 ml of hydrogen was 664.88s, 349.24s, 244.21s, and 230.08s, In addition efficiency rose with each added current, 41.122%, 46.973%, 50.322%, 47.982%, and 44.562%. Higher applied currents initially enhanced the yield. However, beyond a certain threshold, further increases in current lead to a decline in efficiency owing to limitations in mass transport and bubble formation in and around the cell. Regarding the effect of temperature and electrolyte concentration on the rate of hydrogen production, as the temperature raised at 10 K intervals (303.15, 313.15, 323.15, 333.15, and 343.15 K), the time needed to reach 10 ml of hydrogen by volume reduced in higher order of magnitude (312.61, 267.61, 233.96, 189.72, and 184.18 s, respectively). In addition, the efficiency of the hydrogen production rate improved at each added current: 45.173%, 51.84%, 56.623%, 62.31%, and 67.735%. Although high temperatures improve efficiency, they are not favored because of the higher operating costs. The effect of the electrolyte concentration was also significant in terms of the hydrogen rate. At a current of 0.25 A for all ranges of concentration tested (5, 10 g/l; 15g/l and 20 g/l NaOH), the time(s) to reach 10 ml by volume of hydrogen was 341.58s, 276s, 236.18, and 209.57 s, respectively. This was due to the higher ionic mobility with an enhanced concentration of the electrolyte. Generally, the hydrogen production yield reached approximately 57% efficiency at a temperature of 323.15 K, current of 0.6A, and concentration of 10 g/NaOH from the alkaline wastewater, highlighting the potential of this method for generating hydrogen from an abundant and environmentally friendly resource. Future research should focus on further optimization strategies, long-term stability of electrodes in wastewater electrolysis, and economic feasibility of scaling up this process for practical applications.Item Development Of Solar Absorption Refrigeration System for Off-Grid Application(Mekelle University, 2025-07-02) Merhawit G/medhinElectricity has a vital role in improving the quality of life as it is used in activities such as lighting, heating, air conditioning, refrigeration, transportation, health, communication, entertainment, etc. Lack of electricity can affect the health and agricultural sectors as many of vaccines and agricultural products go to waste to the absence of proper preservation facilities. To minimize cold preservation problem, a vapor absorption refrigeration system which operates by solar energy was developed, manufactured and experimentally tested. The system use dammonia -water refrigerant absorbent combination. From the cooling load analysis capacity of the system was computed as 55W which is relatively low but enough for the prototype. The system uses 0.39 m² area of the flat plate collector and the solar radiation intensity on inclined surface of the location obtained was about 784 W/m². The calculated COP of the system was 0.45, with a generator heat input of 120.9 W. This result is favorable when compared to prior studies, which reported COPs in the range of 0.1 to 0.4. The experimental tests recorded absorber plate and generator temperatures of 100°C and 80°C,n respectively. While the generator performance yielded favorable results, further system evaluation was hindered by ammonia leakage. Despite the inability to conduct additional tests due to limited ammonia solution availability, the overall findings indicate with improvements in system sealing and ammonia supply, the proposed system shows promise for rural healthcare and agricultural preservationItem DETERMINATION OF SPECIFIC HEAT CAPACITY FOR FOOD ITEMS(Mekelle University, 2025-02-25) Goitom Zeberhe GebeyaThe primary objective of this study was to determine the specific heat capacity of various food items experimentally. The study involved the development of the experimental setup and the execution of the experiment on some selected food items. An indirect calorimetric method of mixture experimental setup has been developed to determine the specific heats of some selected foods and prepared traditional foods mainly found in Ethiopia, which is commonly known as Injera. This method involved the modification of a heat preservation portable food storage container, purchased from a local market, to serve as a calorimeter. The calorimeter utilized in this study was a 1.9-liter wide-mouth, vacuum flask designed to keep food at a desired temperature for an extended period by minimizing heat transfer with its surroundings. Initially, four runs were conducted for the determination of the calorimeter’s specific heat capacity by employing hot water, which is found to be an average 1.003 kJ/oC. It is important to note that the plastic pouch is considered to be an integral component of the calorimeter, as both the calorimeter and plastic pouch were acquired from the local market. To prevent direct contact between the food sample and the heat exchange medium within the calorimeter, the food sample was placed within the plastic pouches. Consequently; the assessment of heat solution for dissolved chemicals in food was eliminated. The specific heat values of carrots, potatoes, onions, cabbage and Injera using predictive models at an average temperature were determined as 4.365, 4.086,4.423, 4.505 and 3.433 kJ/(kg oC), and the experimental results of these foods were found to be 4.671, 4.290, 4.688, 4.820 and 3.710 kJ/(kg oC) respectively, here the same amount of mass of samples and water, materials and methodology, by the indirect method of a mixture of calorimetry is used. Also four trials are were conducted for the determination of the specific heat capacity of potatoes, carrots, onions, cabbage and Injera. The comparison between the experimental and the predictive models exhibited an excellent level of agreement with percentage error of 5% to 10% for the above foods. This indicates that experimental specific heat capacity measurement is consistent and validate with the predictive value within an acceptable range of error.