Al-Qadisiyah Journal for Engineering Sciences

Abstract Advances in smart materials have made it possible to develop shape-changing wing concepts as alternatives to traditional high-lift systems. In this study, the aerodynamic effects of linear beam extension on a NACA 0015 wing profile with an initial beam length of 150 mm were numerically investigated. The linear actuation mechanism applied along the chord direction resulted in a reduction in the camber ratio. The aerodynamic performance of the conformable configurations was evaluated using CFD analyses conducted under low Reynolds number conditions and employing the k- SST turbulence model. The results indicate that chordwise deformation can improve aerodynamic performance under various operating conditions. This approach offers significant potential for enhancing maneuverability and reducing energy consumption in low-Reynolds-number aircraft, presenting a promising solution for future adaptive wing designs.

Abstract This work examines notch sensitivity in fiber-reinforced polymer composites, with attention to the role of fiber orientation and notch width. CFRP and GFRP specimens were fabricated by vacuum-assisted resin transfer molding (VARTM) using thermoset resin systems. The tested variables were fiber orientation (0^o and 90^o), notch width (0, 2, 4, and 6 mm), and tensile tests were carried out according to ASTM D638. The results showed that the 0° specimens had noticeably higher strength than the 90^o specimens because the fibers were aligned with the loading direction. The 90^o specimens showed lower strength and a more gradual failure response, mainly due to matrix-dominated behavior. Increasing the notch width reduced the ultimate tensile strength, especially for 4 and 6 mm notches, where fracture started near the notch tip because of stress concentration. Unnotched and 2 mm notched specimens provided the best balance between strength retention and practical manufacturability. These results confirm that careful fiber alignment and notch control are important for composite parts used in aerospace, automotive, and civil engineering structures

Abstract This paper presents a technical and environmental assessment of a 3 kWp grid-connected residential rooftop PV system in Al-Diwaniyah, Iraq, using PVsyst 8.0.19. Four scenarios were analysed: monofacial and bifacial PV panels with and without a 5 kWh LiFePO4 battery, plus an expansion sensitivity case using a 10 kWh battery. The battery-free system generated 6,444.8 kWh/year, with a performance ratio (PR) of 80.72%, specific yield of 1,790 kWh/kWp/year, solar fraction of 64.37%, and grid imports of 1,262.2 kWh/year. Adding a 5 kWh battery slightly reduced PR to 77.86% due to charge/discharge losses but increased the solar fraction to 93.00% and reduced grid imports by 80.4% to 247.98 kWh/year. Bifacial panels improved annual production by about 90 kWh/year (+1.4%) and increased PR by 1.13 percentage points in both storage and non-storage cases. Expanding storage to 10 kWh raised the solar fraction only from 93.0% to 96.7%, showing diminishing returns and doubling the cost. Environmentally, the system avoids about 118.4 tCO₂ over 25 years, equivalent to 5,381 trees or removing 25.7 cars annually, with an avoided carbon cost of USD 5,920. The 5 kWh monofacial battery system is the optimal configuration for residential energy independence in the Iraqi context.

Abstract In recent years, drone technology has become very significant in many industrial applications especially for civil infrastructure inspection. In this paper, we present a cascade Proportional Integral Derivative (PID) controller supported by an Artificial Intelligence (AI)-based defect detection system by using You Only Look Once (YOLOv8) algorithm using a drone for civil infrastructure. In conventional inspections, the inspectors are facing difficulties in identifying defects because of old and hazardous buildings, unseen small defects and having substantial safety risks while inspecting high-risk building or bridge structures. This study developed a low-cost Do It Yourself (DIY) drone which was outfitted with a flight controller and First Person View (FPV) camera to capture image in real-world scenarios. The developed AI-based DIY drone system utilized a high-resolution imaging camera which enables rapid and remote data acquisition. During flight testing, the camera captured 60 frames per second of real-time footage while maintaining stable navigation and carrying a payload of up to 800 grammes. The YOLOv8 model trained, validated and tested 6,998 annotated photos, which showed a high mean Average Precision (mAP@0.5) of 99.4%, precision of 96.9%, and recall of 98.4%. The results ascertained that the system can reliably identify structural flaws like cracks, corrosion, peeling paint, and water seepage in difficult environmental conditions.

Abstract This study experimentally investigates the effect of hydrogen enrichment on combustion characteristics, engine performance, and exhaust emissions of a four-stroke spark-ignition (SI) gasoline engine. A single-cylinder, 0.61-L, air-cooled engine was operated at 2300 rpm under full load with hydrogen blending ratios of 5%, 10%, 15%, and 20% by fuel energy, using unleaded gasoline (RON 95) as the base fuel. Hydrogen was delivered through a dedicated port injector upstream of the intake valve. Peak cylinder pressure increased by 17.6% (4.82 to 5.67 MPa at H20%), and the 10–90% mass-fraction-burn duration decreased by 31.6% (38 to 26 °CA), driven by hydrogen’s high laminar flame speed (237 cm/s) and wide flammability range (4–75 vol%). Brake thermal efficiency peaked at H15% (32.1%, +12.6%), while brake-specific fuel consumption fell by 17.35% at H20%. Combustion stability improved by 60.7%, with COV of IMEP reduced from 2.8% to 1.1%. CO, HC, and CO₂ emissions decreased by 81%, 66.5%, and 25%, respectively, with the average unburned-HC carbon chain length reduced from C₆.₂ to C₃.₁. However, NOx emissions rose by 338.7% due to higher peak combustion temperatures activating the thermal (Zeldovich) mechanism. The optimal blending ratio is 10–15%, balancing efficiency gains against NOx penalties addressable through established aftertreatment strategies.

Abstract With the advances in technology, sustainable renewable energy implementation in many applications is becoming important, such as in wireless sensors. Vibration energy harvesting can convert environmental mechanical vibration into useful energy. Honeycomb core structure has shown promising results in cantilever dynamic vibration. However, there is a limited study on its structural variation. This research focuses on different beam thicknesses and angle orientations of 3D-printed hexagonal core structures to improve vibrational cantilever energy harvesting. The beam thickness was studied at 4 mm, 6 mm, and 8 mm with a re-oriented honeycomb core at 0° and 30°. The test rig was modelled as a mass-spring system. The model was simulated for modal analysis and power generation with piezoelectric. The natural frequencies and vibration amplitudes were compared between simulation and experimentation with a vibrational shaker machine and a data acquisition device. The results showed that the 30° honeycomb core has better dynamical amplitudes and energy harvesting as compared to the conventional 0° honeycomb core beam. The different beam thicknesses affect the beam stiffness and, therefore, vary the vibrational amplitude and generated power. The 30° core with lower thickness was found to have the highest power generation due to the better distribution of stress along the beam.

Abstract The stability analysis of Marangoni magneto-convection (MMC) is investigated in a two-layer system consisting of an electrically conductive fluid-saturated porous layer overlain by an identical fluid layer, incorporating variable heat sources and a uniform magnetic field. The upper fluid surface is free, allowing surface-tension-driven convection, while the lower porous boundary is rigid. Two thermal boundary conditions are examined: (i) adiabatic–adiabatic (A–A) and (ii) adiabatic–isothermal (A–I). The governing equations are solved analytically using an exact method to obtain the thermal Marangoni number, an eigenvalue, as a function of depth ratio, Darcy number, Chandrasekhar number, internal Rayleigh numbers, wave number, and thermal diffusivity ratio. Graphical results show that the onset of MMC can be either advanced or delayed by appropriate choices of depth ratio and thermal boundary conditions. The novelty of the present work lies in deriving closed-form expressions for a composite fluid–porous system with simultaneous consideration of variable internal heat sources and magnetic effects under dual thermal boundary conditions, and demonstrating how depth ratio and thermal boundary conditions can be strategically tuned to either advance or delay the onset of instability.

Abstract This work creates a simulation-based scheme to optimize Proton Exchange Membrane Fuel Cells (PEMFCs) in the maritime sector, focusing on the interim functions of thermal, water, and hydrogen pathways in defining efficiency and sustainability. Findings indicate that although peak efficiencies are close to 0.90, dependable operation is limited to 0.84 -0.87, better than the hydration limit of 0.82 and worse than the thermal instability threshold of 0.88. The best hydrogen usage is between 70 -82 because lower percentages were tiger and higher percentages were almost 2 times higher rates of degradation when 0.006 V/1000h (harbour) and 0.012 V/1000h (sprint) were used in respectively. Mode comparison proves cruise operation at 91% net efficiency, 13% auxiliary demand, and 27% performance 27 % Excellent, 36% Good, 3% Fail, and sprinting is 86% efficiency and 16% auxiliaries with 27% Fail/Poor results. This study outsmarts the other studies by being the first to establish quantitative safe operation envelopes of maritime PEMFCs and provide a workable blueprint of sustainable deployment by integrating radar, multi-panel, and 3D threshold-based analysis.

Abstract This paper presents a comprehensive study on the structural synthesis and classification of planetary gear mechanisms (PGCMs), which combine the advantages of planetary gear trains (PGTs) and cam mechanisms to produce precise, intermittent, or variable-speed motions. These mechanisms are particularly suitable for high-performance industrial applications, such as indexing tables, path generation systems, and rigid body guidance. The work begins by detailing the kinematic and structural characteristics of PGCMs and identifying possible configurations based on degrees of freedom, link types, and joint arrangements. Using graph theory, rooted graph representations are developed to systematically enumerate two-degree-of-freedom PGCMs, up to seven links. A spanning-tree-based synthesis method is used to generate candidate structures, followed by genetic compatibility analysis to identify viable PGCM configurations. The proposed method produces a set of functionally and structurally distinct PGCMs, including a novel five-link mechanism that achieves precise path generation with minimal complexity. This study not only enhances the theoretical framework for PGCM design, but also provides a practical basis for its application in modern mechanical systems.

Abstract This article delves into the intricate dynamics of groundwater flow within duct systems, examining both critical and sub-critical flow conditions. Employing mathematical models, sophisticated potential methodologies, numerical simulations, and flow net analysis, the research investigates the behaviour of the phreatic surface under varying flow coefficients m and slope angles θ. Noteworthy discoveries include the significant influence of the flow coefficient on the curvature and deflection of the phreatic surface, with higher m values resulting in steeper slopes. Additionally, the study emphasizes that changes in slope angle θ impact the interface's shape, leading to variations in flow depth. Innovative visualizations incorporating streamlines and velocity potential contours offer insights into flow patterns, recirculation zones, and potential turbulence areas. These critical findings supply essential insights for enhancing environmental strategies, optimizing water resource management, and improving the efficiency of fluid systems. The study emphasises how important it is to use flow net analysis and thoroughly investigate critical and sub-critical flow scenarios in order to handle issues related to groundwater management and sustainability. Stakeholder can enhance their capacity for fluid system optimization by applying these analytical tools, leading to improved environmental outcomes and informed decision-making.

Abstract Generally, the production processes of citronella (Cymbopogon Nardus) oil refining in Aceh are traditionally carried out, making them less efficient in resource usage. Every activity along the citronella supply chain has an environmental impact due to raw materials, water, and energy resources. Therefore, this study aimed to assess the environmental impacts caused by activities along the citronella oil supply chain based on a life cycle assessment framework. We compared two production process methods, namely a distillation system with one boiler for one kettle and one boiler for three kettles. The environmental impacts measured include greenhouse gas emissions, global warming potential, land use, and air acidification. Research stages involved determining goal and scope, data collection, environmental impact measurement, interpretation, and proposals for improving the production process. The results showed that the production process of a single boiler system for three kettles had an environmental impact lower than the other method. Furthermore, the distillation process and solid waste combustion have a significant impact on the environment, hence they need to be improved. This life cycle assessment of the citronella oil supply chain is the basis for enhancing the production process to reduce environmental impact.

Abstract The current study's objective is to use Diesel-RK simulation software to numerically assess the effects of employing waste plastic oil blends on the thermal characteristics of diesel engines. Each autonomous zone's governing equations are solved using the multi-zone combustion model. Six distinct volumetric mixes were used to analyze the engine's characteristics of waste plastic oil (10%, 20%, 30%, 50%, 70% and 100%) as a comparison to the standard diesel case. The data collected showed a slight decrease in pressure and heat release for all waste plastic oil blends compared to pure diesel fuel. The Sauter mean diameter of droplets increased by 0.91%, 1.85%, 2.68%, 4.35%,5.74% and 7.1% for 10%, 20%,30%, 50%, 70%, and 100\% waste plastic oil (WPO), respectively. The slightly lower cetane number of WPO compared to fossil diesel resulted in a longer ignition delay, resulting in a slightly later combustion start. Brake specific fuel consumption (BSFC) increased by 2.2%, 4.1%, 5.86%, 9.23%, 15.14%, and 15.960% for 10%, 20%,30%, 50%, 70%, and 100% WPO, respectively, because of differences in density, viscosity, and heat content, respectively. A significant drop in the Bosch Smoke Number (BSN) was observed with 30% and 50% WPO, reporting reductions by 2.86% and 4.55%, respectively. The lowest increase in particulate matter was 1.96% and 2.87% for 30% and 50% WPO biodiesel blends. A higher biodiesel content resulted in lower NOx emissions compared to diesel. The findings suggest that 30% WPO is the optimal blend recommended for use in a diesel engine without alteration, which aligns with the results from other studies.

Abstract This study presents a simulation of electricity generation systems utilizing solar energy, employing TRNSYS and EES software to address the energy needs of isolated areas in Algeria. Two solar energy systems were compared: the CSP-ORC and the Photovoltaic, analyzed across three regions: Adrar, Illizi, and El-Bayadh. The CSP-ORC system was enhanced by incorporating components for optimizing the operation of the pump within the ORC, as well as integrating a solar photovoltaic system with battery storage at a capacity of 50 kW. The estimated electrical power generated by the studied systems is approximately 1 MW. We compared the technical performance of a 1 MW s-ORC system with thermal energy storage against that of a solar photovoltaic system of the same capacity. This analysis underscores the viability of both CSP-ORC and PV systems for electricity generation in isolated arid regions of Algeria. However, the superior performance of the PV system, particularly during the winter months, suggests that while CSP-ORC systems are promising, they may require further enhancements or integrated solutions (such as hybrid systems) to improve output and reliability across all seasons. The economic analysis highlights the cost-effectiveness of PV systems, which have lower investment, maintenance costs, and LCOE than CSP-ORC. The lowest LCOE (0.0311 €/kWh) and fastest payback (3.62 years) were observed in Illizi for PV, while CSP-ORC had the highest LCOE in El-Bayadh. Environmentally, PV reduces 55.2 tons of CO₂ emissions in Illizi, whereas CSP-ORC, generating more electricity, prevents 84 tons. Both systems significantly cut emissions compared to diesel generators.

Abstract This work examines the two-dimensional continuous flow of a Casson-Williamson fluid over a stretched surface under a Darcy-Forchheimer permeable medium. Several elements can affect the flow, including Joule heating, radiation, chemical reactions, thermal sources, electric field influences, and magnetic field influences. Nonlinear partial differential equations articulate the fundamental equations governing the system's dynamics in this physical model. We simplify these equations to a system of nonlinear ordinary differential equations by applying requisite changes. The Keller Box technique is utilized to simplify this collection of ordinary differential equations. Velocity, temperature and concentration graphs are plotted. The velocity profiles decline with a rise in the Casson parameter, magnetic parameter, porous parameter, Weissenberg number, and velocity slip parameter. Still, the electric field parameter diminishes when the speed slip constraint is enhanced. This study primarily examines several local properties, including the skin resistance coefficient, the Nusselt number, and the Sherwood numbers. We compare our results with the current literature by computing the skin friction coefficient for different inputs of the Casson factor. Prior studies have yielded results that are fairly congruent with this one.