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Research Article
Design, Realisation and Performance Evaluation of an Optimised Drying Oven for Maize Post-Harvest Processing
Noutegomo Boris*
Issue:
Volume 14, Issue 5, October 2026
Pages:
88-96
Received:
15 April 2026
Accepted:
13 June 2026
Published:
21 October 2026
Abstract: Post-harvest losses in maize production remain a major challenge in many developing countries due to inefficient traditional drying methods such as sun drying, which often result in microbial contamination, reduced grain quality, and economic losses associated with high residual moisture content. This study presents the design, realization, and performance evaluation of an optimized drying oven for maize post-harvest processing. The system was designed using functional and structural engineering approaches with modelling carried out in SolidWorks, while airflow and heat distribution within the drying chamber were analysed using computational fluid dynamics (CFD) simulations. The developed prototype features an insulated drying chamber, dual-fan air circulation, and sensor-based temperature control to enhance thermal uniformity and energy efficiency. Experimental drying tests were conducted on 7.5 kg of maize at 50°C, 55°C, and 60°C, with temperature and moisture variations monitored using thermocouples and moisture analysers. Results showed that moisture ratio decreased steadily with drying time, with drying duration reducing from 300 min at 50°C to 240 min at 60°C. The drying process occurred mainly in the falling-rate period, indicating moisture diffusion as the dominant mechanism. Energy efficiency increased from 75.57% to 80.96%, and final moisture content reached the safe storage range of 13-14%. The results demonstrate that the developed drying oven provides an efficient, reliable, and scalable solution for maize drying, contributing to improved post-harvest handling and reduced grain losses.
Abstract: Post-harvest losses in maize production remain a major challenge in many developing countries due to inefficient traditional drying methods such as sun drying, which often result in microbial contamination, reduced grain quality, and economic losses associated with high residual moisture content. This study presents the design, realization, and per...
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Research Article
Experimental Exploration into Al 7075-T651 Machinability, Surface Quality, and MRR Using Avocado Cutting Fluid via Grey Optimization
Abera Ayza Anebo*,
Temesgen Hailegirogis,
Workineh Gebeyehu,
Biniyam Bekele Toma
Issue:
Volume 14, Issue 5, October 2026
Pages:
97-113
Received:
22 September 2026
Accepted:
4 October 2026
Published:
21 October 2026
Abstract: This research aims to identify the optimal machining parameters for turning Aluminium Alloy 075-T651 using a tungsten carbide insert cutting tool and a flood coolant system, applying the Grey-based Taguchi method. Aluminium Alloy 075-T651 is commonly utilized in the automotive, marine, machine tools, and aerospace industries due to its excellent weight-to-strength ratio. A key focus of the study are the surface roughness and material removal rate, which is critical in machining. The research explores how various turning parameters affect surface roughness and material removal rate with investigates the role of coolant in these operations. Heat generated during machining can adversely affect tool life, workpiece dimensions, and surface quality. To address these challenges, an environmentally friendly, biodegradable, and non-toxic avocado oil-based cutting fluid was employed. An orthogonal array from the Taguchi method guided the experiments, with surface roughness and material removal rate measured as a response. Minitab software facilitated the statistical analysis of process parameters. Key performance metrics included material removal rate, and surface roughness, influenced by cutting speed, feed rate, depth of cut, and avocado oil proportion. So, an avocado oil (9%), depth of cut (1.0 mm), cutting speed (1000 rpm), and feed rate (85 mm/min) are an optimized parameter.
Abstract: This research aims to identify the optimal machining parameters for turning Aluminium Alloy 075-T651 using a tungsten carbide insert cutting tool and a flood coolant system, applying the Grey-based Taguchi method. Aluminium Alloy 075-T651 is commonly utilized in the automotive, marine, machine tools, and aerospace industries due to its excellent we...
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Research Article
Numerical Investigation of the Performance of a Vortex Tube-Based Vehicle Cabin Cooling System
Sintayehu Assefa Endaylalu*,
Genet Tesfaye Degene
Issue:
Volume 14, Issue 5, October 2026
Pages:
114-126
Received:
3 September 2026
Accepted:
14 September 2026
Published:
21 October 2026
Abstract: The vortex tube is a fundamental device that produces two different temperatures and low-pressure flows from a single compressed, high-pressure, high-temperature flow. It is a stationary device used to separate the compressed air into cold and hot streams. Its function is based on the concept of air vortex stream movement. Conventional automotive air conditioning systems use refrigerants and vapor compression cycles, which contribute to high energy use and greenhouse emissions. Therefore, this work focused on a numerical study of the performance of a vortex tube for vehicle cabin cooling system applications by considering the inlet nozzles, cold-end diameter, and hot-tube length. The study was conducted with various inlet pressures from 4 to 7 bar, cold mass fractions from 0.3 to 0.5, and hot-tube parameters using a tube length of 106mm as a baseline, and also length-to-diameter ratios of 10, 15, and 20. The results show that increasing inlet pressure increases cooling capacity but reduces the coefficient of performance, while a higher cold mass fraction improves cooling load with moderate efficiency gains. The hot-tube length optimization showed that longer tubes slightly increase cooling capacity, but do not significantly improve the coefficient of performance, which indicates diminishing returns beyond a length-to-diameter ratio of approximately 10 to 15. Similarly, the cold-end diameter optimizations indicated that a strong influence was observed with the best configuration of hot tube length 115mm per unit tube diameter 1.4mm and 8 mm cold-end diameter at 4bar inlet pressure and cold mass fraction of 0.5 achieved a cooling load of 119W at COP 0.232. Finally, this study concludes that hot tube length offers incremental gains, while cold-end geometry is the key driver for improving vortex tube performance in vehicle cooling systems.
Abstract: The vortex tube is a fundamental device that produces two different temperatures and low-pressure flows from a single compressed, high-pressure, high-temperature flow. It is a stationary device used to separate the compressed air into cold and hot streams. Its function is based on the concept of air vortex stream movement. Conventional automotive a...
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Research Article
Interdisciplinary Approach to Safety-Ergonomic Parameters of Tractors During Agro-technical Operations
Petrovic Predrag*,
Spajic Branko,
Stjelja Zivko
Issue:
Volume 14, Issue 5, October 2026
Pages:
127-131
Received:
14 September 2026
Accepted:
27 September 2026
Published:
23 October 2026
Abstract: In Serbia, there is a large number of tractors in operation with a considerable age structure, without a cab or a protective frame. These facts contribute to a significant increase in the number of accidents with injured and fatal persons during exploitation and transport, primarily due to the lack of evident subjective: safety, ergonomic, comfort, and other parameters. Tractors, due to their construction and traction characteristics (high geometric and mass center of gravity, large dynamic wheel radii, large clearance, high engine power, large transmission load variations, agro-technical operations on variable configurations, with falls and ascents, etc.), are very unstable working machines despite relatively low movement speeds. In order to influence the reduction of the number of accidents, ergonomics investigates the "man-machine-environment" relationship, which studies anatomical, physiological, medical, social, legal and other areas that contribute to the reduction of accidents and occupational diseases, while increasing efficiency, reliability, safety, etc. Special attention should be paid to the balance of forces within the analysis of the required static and dynamic stability of the tractor when moving up and down the sloping surface of the working terrain, especially tractors without a cab or a protective frame. In addition to the general state of tractor safety, this paper presents a draft of a short analysis of tractor exploitation when performing work operations on ups and downs in agro-technical and transport conditions, as one of the main reasons for accidents with injured and fatal persons. Also, the basic ergonomic-ecological parameters that are necessary to achieve the necessary, safety, ecological, medical, social, legal and other parameters are presented.
Abstract: In Serbia, there is a large number of tractors in operation with a considerable age structure, without a cab or a protective frame. These facts contribute to a significant increase in the number of accidents with injured and fatal persons during exploitation and transport, primarily due to the lack of evident subjective: safety, ergonomic, comfort,...
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Research Article
Theoretical-analytical Solution to the Problem of Steady Subcritical Flow of Gaseous Coolant in Branches of Pipelines of Heat Exchange Units
Lobanov Igor Evgenievich*
Issue:
Volume 14, Issue 5, October 2026
Pages:
132-140
Received:
24 June 2026
Accepted:
21 August 2026
Published:
26 October 2026
DOI:
10.11648/j.ijmea.20261405.15
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Views:
Abstract: The study provides analytical solutions to the problem of determining the flow parameters at the branch points of the coolant flow in a heat exchanger line. Previously, only numerical solutions to the problem were considered. In this work, the choice of a theoretical model for mathematical modeling of the flow of a refrigerant in a gas in the heat exchange line branch is justified, which shows an acceptable level of approximation to the real flow and the required computational complexity: a thermodynamic model of a stable subcritical flow of compressed gas. With the appropriate analog definition of boundary conditions, the problem of determining the parameters of the gas refrigerant in the heat exchanger tube bend can be solved analytically much easier than for a T-shaped connector. The analytical solutions presented for the specific problem of combining the gas refrigerant flow in the heat exchanger line serve as a basis for performing similar analytical solutions for the separation of the flows. The following results were obtained in this study: Analytical solutions for the dual flow problem of the gas refrigerant flow in the heat exchanger line, previously only numerical solutions were available for this problem.
Abstract: The study provides analytical solutions to the problem of determining the flow parameters at the branch points of the coolant flow in a heat exchanger line. Previously, only numerical solutions to the problem were considered. In this work, the choice of a theoretical model for mathematical modeling of the flow of a refrigerant in a gas in the heat ...
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Research Article
Mitigating Weld Defects in AISI 4145 Medium-Carbon Steel During Shielded Metal Arc Welding
Issue:
Volume 14, Issue 5, October 2026
Pages:
141-157
Received:
27 August 2026
Accepted:
28 September 2026
Published:
26 October 2026
DOI:
10.11648/j.ijmea.20261405.16
Downloads:
Views:
Abstract: Welding defects pose significant challenges to product quality and productivity in manufacturing industries. Shielded metal arc welding (SMAW) is the most widely used welding method in developing countries such as Ethiopia. This thesis identifies and addresses the root causes of welding defects in SMAW of medium carbon steel (AISI 4145) at Akaki Basic Metal Industry (ABMI), and optimizes welding parameters to enhance weld quality and reduce defect rates. Pareto analysis identified porosity and undercut as the most critical defects, together accounting for a 6% rejection rate in production over two years. Ishikawa (cause-and-effect) diagrams were used to analyze the root causes of these defects in detail, including incorrect welding parameters, inadequate preheat/post-heat treatment, improper technique, and inconsistent quality checks. A Taguchi L9 orthogonal array was then applied to optimize welding current, voltage, and speed. Welding current had the greatest effect on tensile strength (72.18% contribution), followed by voltage (19.73%) and speed (3.88%). Applying the optimized parameters (140 A, 40 V, 80 mm/s) reduced the defect rate from 6% to 2.7%. The study concludes that systematic optimization of welding parameters can effectively mitigate defects, improve weld quality, and enhance productivity in SMAW processes.
Abstract: Welding defects pose significant challenges to product quality and productivity in manufacturing industries. Shielded metal arc welding (SMAW) is the most widely used welding method in developing countries such as Ethiopia. This thesis identifies and addresses the root causes of welding defects in SMAW of medium carbon steel (AISI 4145) at Akaki Ba...
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