بحوث سكوبس — ايناس رضا علي

Conventional solar air heaters often suffer from limited heat transfer efficiency due to suboptimal absorber plate designs and high irreversibility, constraining their applicability in thermal energy systems. Addressing this limitation, the present study develops and validates a comprehensive mathematical model—implemented in MATLAB—for a double-pass solar air heater equipped with a novel serrated absorber plate. The primary objective is to quantify the enhancements in both energy and exergy performance and to identify the governing design and operating parameters. The model incorporates detailed energy and exergy balance equations for all system components and shows strong agreement with previous experimental data. Parametric analysis reveals that increasing the gap between the glass cover and absorber plate results in an 11% increase in thermal efficiency and a 21% improvement in exergy efficiency. Additional findings highlight the positive influence of fin height, air mass flow rate, and solar irradiance on system performance, while acknowledging the tradeoff of increased pressure drop. Qualitatively, the serrated geometry enhances turbulence, boosts heat transfer, and lowers entropy generation relative to flat absorbers. These results have practical implications for designing cost-effective, high-performance solar air heaters suitable for drying, space heating, and renewable thermal applications, thereby contributing to sustainable energy system optimization. © The Author(s) 2025. This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 License (https://creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access page (https://us.sagepub.com/en-us/nam/open-access-at-sage).

Purpose: Biodiesel is a non-toxic, renewable, and environmentally friendly fuel used in compression ignition engines. This work aimed to develop Fe3O4/SiO2 as a cheap, magnetic, and easy separable catalyst for biodiesel production from waste oil by sono-catalytic transesterification. Methods: Fe₃O₄-SiO₂ was prepared using a modified Stober method and used as a heterogeneous catalyst in an ultrasound-assisted transesterification reaction to produce biodiesel. The tests were designed by the Response surface methodology by considering the molar ratio of methanol to oil (M/O), catalyst weight percentage, and sonication time as independent factors. The produced biodiesel in diesel generator engines and the emission of pollutants were evaluated. Results: The optimal production conditions were determined using the response surface methodology, which included a molar ratio of 8.30, a catalyst weight percentage of 5.30, and a sonication time of 30.02 min. The Pareto analysis indicated that the sonication time is the most important factor in the sono-catalytic transesterification of waste oil. The evaluation of the produced fuel showed that with an increase in the percentage of biodiesel in the engine's fuel input, CO emissions decreased by 0.027 % and smoke levels by 24 %, while NOx levels increased by 495 ppm. Additionally, the increase in biodiesel percentage led to a rise in brake-specific power by 44.6 kW and brake-specific fuel consumption by 89 g/kWh though brake torque decreased by 87 Nm. Conclusion: The study introduces significant advancements in biodiesel production technology through combining heterogeneous catalysis and ultrasound processing, optimizing production parameters for efficiency and sustainability while demonstrating improved environmental performance in diesel engines. © 2024 The Authors

The stepped channel is crucial in heat exchange applications. This paper aims to passively enhance heat transmission in a uniquely designed stepped channel. Three mechanisms are proposed: waving the channel's lower wall, filling the wavy channel with a porous medium, and dispersing alumina nanoparticles in the flowing base liquid. The problem, discretized and analyzed using the finite element method, is examined from the perspectives of geometrical configuration, operational conditions, and aspects of the porous medium. The study reveals that the role of waving the channel is the most significant among the parameters, as indicated by a 63% increase in the Nusselt number when the flat wall is waved with an amplitude of 0.15, compared to only a 6.3% increase when the concentration of alumina nanoparticles is raised from 0 to 4%. It is noted that the Darcy number reduces the average Nusselt number by 19.7%, which is greater than the reduction caused by porosity at 6.6%. The skin friction decreases with increases in the Darcy number, Reynolds number, and porosity, whereas it increases with the amplitude of the wavy channel. Cooling systems for heat-releasing equipment are an obvious application for such a study. © 2025 Elsevier Ltd

This study scrutinizes the aspects of transferring the heat and the generated irreversibility from a hot wavy wall covered by a surface wavy porous layer. This combined wall represents a heat sink and compromise the lower wall of a horizontal channel with moving upper wall under the condition of partial slip, which is encountered in high temperature applications. Alumina-water nanofluid is forced through the channel. The investigated parameters are relating to the aspect of the porous surface layer (Darcy number and the porosity), Waviness of the lower wall (number of undulations), slip boundary condition, nanoparticles fraction and the Re number. The finite element method is used to solve the problem numerically. The results suggest that the partial slip condition slightly lowers the Nusselt number (5%) and lowers the pressure drop too. The wavy style augments Nu number by 37% for three undulations and lowers the pressure drop and mitigates the fluid flow irreversibility. Advantages are obtained from raising the Darcy and Reynolds numbers and the porosity of the wavy porous layer, where Nu rises by 28%, 33% and 23% when Da, Re and the porosity are escalated, respectively as follows: to 0.01, 100 to 300 and 0.2 to 0.8. © The Author(s), under exclusive licence to Springer Nature India Private Limited 2025.

In this study, numerical analysis of a porous block influence on the mixed convection in a cavity filled with nanfluid has been investigated. The cavity is curvilinear shaped, in which the cold side is the top which is split to move in two directions on the same plane. The base is partially heated and connected to a block of porous media, while other walls are adiabatic. The complex governingequations are solved numerically using the finite element technique. For the assessment of the thermal performance, the considered variables which are Richardson number (from 0.15 to 10), Reynolds number (from 25 to 200), Darcy number (from 10−5 to 10−1), Hartmann number (from 0 to 62), ma magnetohydrodynamic's inclination angle (from 0° to 90º) and nanoparticles concentration (from 0 to 0.08). The height of the porous block is also investigated. The results’ main finding stated that the heat transfer could be enhanced due to the rise in Reynolds number, Richardson number, and the volume concentration while decreasing with the rise of Hartmann number. Also, value of Nuavg and the streams’ strength increase with the increase in Darcy number. © 2024 The Author(s)

This work has numerically investigated the double diffusion of free convection in a curvilinear enclosure filled with nanoliquid and containing fins with heat generation/absorption. The considered enclosure, the curvilinear cavity, has triple fins connected to the inclined walls, which are hot and have a high intensity of solutal; however, the top wall is cold and low intensity of solutal. The bottom walls, as well as the vertical walls, are considered to be isotopically insulated. The parameters that are considered are Rayleigh (from 103 to 105), Hartmann (from 0 to 60), heat generation/absorption, q, (− 4 to 3), bouncy ratio (N = − 4 to 4), Lewis number (Le = 0.5–10), volume concentration (Φ = 0–0.06) at fixed Prandtl number. The governing equations have been numerically solved and applying the FEM technique. The important findings explain how heat and mass transfer can be improved by increasing the value of Ra, q, and Φ while decreasing with the increase in Ha. Also, the rise of the N ratio and Le number until (N = 2), where the reduction value reaches 44% from (N = − 4) to (N = 2) at (Le = 0.5), and the effect of both N and Le become negligible for (N > 2). Furthermore, the value of Shavg has the same behaviour as Nuavg with N, where Shavg decreases with increasing N and increases with increasing Le, where maximum mass transfer enhancement reaches 65% at N = − 4. The effects of N and Le become negligible at N = 2. © The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2024.

The current research numerically investigated the inclined magnetic field effects on the combined forced and natural convection in lid driven curvilinear cavity filled with Cu-H2O nanoliquid and a partial porous layer. The complex cavity is partially filled with a porous layer about the lower half and heated with a constant heat source. The entire cavity is occupied with Cu-water nanoliquid. The upper horizontal wall is at a cold temperature and moving towards the right with a constant velocity. The geometry is subjected to an inclined magnetic field. The derived mathematical models are computed numerically using the FEM-based tool. The thermal behavior is assessed through a range of variables, such as Richardson number (0.1 to 10), Darcy number (10 -5 to 10 -1), Reynolds number (30 to 200), Hartmann number (0 to 60), γ (0 to 60°), and nanoparticle concentration ϕ (0.0 to 0.06) at constant Prandtl number, Pr = 6.2, and porosity, ε = 0.4. The main findings indicate that heat transfer inside the cavity rise with the increase of Ri, Re, ϕ, and Da numbers, while decreasing with the rise of the MHD strength. Also, at a low Reynolds number, Re = 30, the value of Nuavg only increased by 18% with the increases in Ri number from 0.1 to 10; however, the increase in Nuavg increased to 64% with a high Reynolds number, Re = 200. © 2023 Elsevier B.V.

Problems in autonomous systems may be tackled with the help of the AS-FC-DL approach, which integrates autonomous fuzzy clustering and deep learning methods. The system can anticipate human behavior on crowded roadways by employing these techniques to recognize patterns and extract features from complicated unsupervised data. Each image point's membership value is associated with the cluster's epicenter using the fuzzy clustering methodology in the AS-FC-DL approach. Using least-squares methods, this approach finds the optimal position for each data point within a probability space, which may be anywhere among multiple clusters. Data points from an unlabeled dataset may be organized into distinct groups using a deep learning technique called cluster analysis. Data fusion from many sources, including sensor data and video data, can improve the AS-FC-DL method's precision and performance. The algorithm is able to deliver an all-encompassing and precise evaluation of human behavior on crowded roadways by fusing data from many sources. The AS-FC-DL approach may also be employed in autonomous vehicles to help them learn from their experiences and improve their performance. Using reinforcement learning, a model for autonomous vehicle driving may be constructed. The AS-FC-DL approach helps the self-driving car traverse the area with increased precision and efficiency by allowing it to recognize structures and extract features from complicated unsupervised data. © 2023, American Scientific Publishing Group (ASPG). All rights reserved.

Electromyography (EMG) is a common signal used to detect and categorize various sorts of bodily motions, including, but not limited to, varied positions, gestures, and actions. Because of its efficiency and ease of use, the surface Electromyogram (sEMG) signal was mostly used for analysis. Due to its shortened calculation time, higher efficiency, and good accuracy, the EMG signal was created from the neural excitations of the muscles using an EMG driven neuromuscular model. Time-frequency domain parameters derived from electromyography were used to discuss and quantify musculoskeletal activity. The Hidden Markov Model (HMM) was used to specify the musculoskeletal moment process. Methods based on the Hilbert-Huang Transform (HHT) are used to get around the WT's shortcomings. Artificial neural network (ANN) based methods are utilized for gesture recognition automation. In order to categorize the hand movements, we create a collection of Feed Forward Neural Networks (FFNN) that are educated using a back propagation approach. However, the network has two major drawbacks: it takes a long time to train, and it can't spot outliers. This is why hand gesture recognition utilizes Cascaded Feed Forward Neural Networks. Providing sufficient hidden neurons, the cascaded networks can learn any input-output relationship in a shorter amount of time. It can recognize unusual cases throughout the classification process. Results from the simulations showed that the recommended methods were superior in terms of performance. © 2023 IEEE.

Human health care is one of the main issues related to biomedical engineering specialization. the improvement of the air-breathing quality leads to achieve one of the sustainable development goals (SDGs) which is good health and well-being. So, the purpose of this work is to introduce, design, calibrate, and evaluate a low-cost of the portable-sensor device for monitoring experimentally the dust-particles that are included in the living breathing air in the local city. To offer the low-cost the model was designed using Arduino UNO, dust sensor, temperature, humidity sensor, LCD screen, and alarm. The device checks the efficiency of the air surrounding the human being because dust and heat have a great impact on human health. The sensor device was examined for accuracy through comparing the sensor to an accurate copy sensor of itself with outdoor and indoor climates. It was found that accurate measurements under real-world humid and temperature varying, and dynamically changing conditions were achievable using the proposed sensor when compared to the commercially available sensors. The experimental results showed the proposed dust-sensor device high-quality measurements at economy lower-cost solutions than commercially available sensors for air-quality testing. © 2023 American Institute of Physics Inc.. All rights reserved.

In the present work, a new type of nanofluid called the hybrid nanofluid (Al2O3-Cu-water) is used to enhance the heat transfer. The Finite-Volume-Method (FVM) along with the SIMPLE-algorithm has been utilized to study the heat-transfer and, mixed convection fluid-flow of the hybrid nanofluid (Al2O3-Cu-water), placed within the lid-driven rectangular cavity. The bottom and top walls are subjected to constant high temperature (Th) and low temperature (Tc) respectively. The side walls are treated as adiabatic. The top wall moves in the positive x-direction. The effects of Reynolds number and hybrid nanoparticle volume fraction on the flow field have been investigated. It is found that the mean Nusselt number increases with respect to Reynolds numbers and hybrid nanoparticle volume fraction. © 2022. All Rights Reserved.

Mixed convection in a rectangular double lid-driven cavity filled with hybrid nanofluid (Al2O3–Cu–water) subjected to insulated sidewalls and sinusoidal temperature on horizontal walls is numerically investigated. Using the SIMPLE algorithm for pressure, velocity coupling, the momentum, mass conservation, and energy equations are numerically solved by the finite-volume method (FVM). The data were validated by comparing the present results with the results of the problem solved by Sarris et al. (Numer Heat Transf Part A Appl 42(5):513–530, 2010) for pure liquid. The effects of amplitude ratio, phase deviation, and Reynolds numbers on the flow and heat transfer characteristics are discussed. It is found that the rate of heat transfer is improved as the volume fraction of the hybrid nanoparticles and the amplitude ratio are increased. The non-uniform heating at cavity walls tend to provide higher heat transfer rate and the heat transfer rate increases with respect to Reynolds number. © 2022, The Author(s), under exclusive licence to EDP Sciences, Springer-Verlag GmbH Germany, part of Springer Nature.

Cardiovascular stenting is a mature topic but it is still being developed in the research community because of its importance. To provide worthy information about cardiovascular stenting environments and to give support to the researchers, attention must be given to understand the obtainable choices and gaps in this research field. This work aims to examine and examine the literature of each work related to the placement of cardiovascular stents, the failure of the stents and the models of stent designs to provide a good understanding through the investigation of articles published in various contextual aspects, such as motivations, open-challenges and recommendations to improve the field of stent placement. A systematic review is carried-out to map and examine the articles related to cardiovascular stents, the failure of the stents and the models of stent designs through a coherent-taxonomy used in three well-known scientific databases: ScienceDirect, IEEE Explore, and Web of Science. These databases involve literature that highlight arterial stenting. Based-on our inclusion and exception, a total of 90 articles composed the final set that offer various classes and sub-classes. The first class includes the development studies with (42/90) of experimental, computational and combined experimental and computational studies related to stent models performance and stent failure, the second class discussed studies that have been performed on stent design with (32/90), the third class is focused on the framework studies with (10/90), and the fourth class includes problems of stenting long-term with (6/90). The performance of stent designs, which is a research area that requires periodic controls, tools and procedures that could provide a stent design with good mechanical performance, reduce restenosis in the stent and increase fatigue resistance and durability. There have been numerous studies on stent performance that could promise good results in this field. The fields of research in stent designs vary, but all fields are fundamental equally. The expectation of this work could help to emphasize present research chances and, therefore, expand and make further research fields. © 2022 Universiti Tun Hussein Onn Malaysia Publisher’s Office. All Rights Reserved.

The increasing number of studies on the behaviour of stent placement in recent decades provides a clear understanding of peripheral artery disease (PAD). The severe mechanical loads (axial tension and compression, bending, radial compression and torsion) deformation of the femoropopliteal artery (FPA) is responsible for the highest failure rate of permanent nickel-titanium (Nitinol) stents. Therefore, the purpose of this article is to review research papers that examined the deformation of the natural load environment of FPA, the properties of Nitinol and mechanical considerations. In conclusion, a better understanding of mechanical behaviour for FPA Nitinol stents contributes to increased mechanical performance and fatigue-life. © 2022 Informa UK Limited, trading as Taylor & Francis Group.

The understanding of mixed convection heat transfer in cavity is crucial for studying the energy consumption and efficiency in many engineering devices. In the present work, the hybrid nanofluid (Al2 O3-Cu-Water) is employed to increase the heat transfer rate in a double lid-driven rectangular cavity. The bottom movable horizontal wall is kept at a high temperature while the top movable horizontal wall is kept at a low temperature. The sidewalls are insulated. The mass, momentum and energy equations are numerically solved using the Finite Volume Method (FVM). The SIMPLE algorithm is used for pressure-velocity coupling. Parameters such as Reynold’s number (Re), Richardson number (Ri), moving wall direction, solid volume fraction, and cavity length are studied. The results show that the hybrid nanofluid in the rectangular cavity is able to augment the heat transfer significantly. When Re is high, a big size solid body can augment the heat transfer. Heat transfer increases with respect to Ri. Meanwhile, the local Nusselt number decreases with respect to the cavity length. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.

The use of the stent to treat peripheral artery disease (PAD) is increased and the proportion of failures also increases. The femoropopliteal artery (FPA) experiences a high deformation ratio compared to the cardiovascular artery due to limp flexion and daily activities that could lead to stent failure, as well as increasing the number of observed mortality and morbidity. In the present work, two of the common PAD stent design models represented as STENT I and STENT II were analyzed by using of finite element method (FEM) to simulate the most mechanical loading modes that could occur in FPA, such as axial tension and compression, torsion, three-point bending and radial compression to give a good understanding of deformation that affected stent inside the in-vivo. The gradual force load was used to simulate all modes, the force values are 0.25 N, 0.5 N, 1.5 N, 2.5 N, 3.5 N and 5.5 N until the stent models obtain the yield-point. The comparison of stent models (STENT I, STENT II) was performed in terms of graphs of total deformation, force-stress and stress-strain for all test modes. The similarity ratio of the total deformation in axial tension and the compression mode for STENT I and STENT II was 17% and that may indicate that STENT I obtained a high deformation value instead of STENT II, while, the torsion similarity ratio was 86% which could show a good agreement in this mode, as well as the similarity ratio, was 78% of the total three-point bending deformation and the value of the similarity ratio in the radial compression mode was 23%. Still unclear what is the clinical mode of mechanical deformation that is more important than others with changing the length of the lesion and stent diameter, and the fatigue life test provides a better understanding of the mechanical tests that must be sought. © 2019 UTHM Publisher.