Pub Date : 2025-12-01Epub Date: 2025-12-06DOI: 10.1016/j.jestch.2025.102244
Durjoy Kumar Paul , Hasan Muhommod Robin , Nishitha Paul , Mim Mashrur Ahmed , Mahadi Hasan Masud
Wind tunnel testing of aerial vehicles is a crucial step prior to the commercialization of vehicles. This paper focuses on an overview of common wind tunnel testing methods for various aerial vehicles with detailed specifications and flow conditions inside the wind tunnels. This work begins with the classification of wind tunnels and overviewing their evolution over the years. Later, wind tunnel specifications for testing scaled-down models of aerial vehicles and commercial models were discussed, along with the associated challenges and limitations. Literature reveals that challenges associated with the scaling of aerial vehicles, as well as cost, time, and technological limitations, need to be addressed to increase the accuracy of the wind tunnel testing. Lastly, this work summarizes the key specifications of the wind tunnels individually for different types of aerial vehicles, which will be beneficial for the researchers while selecting the suitable wind tunnel with desired specifications for particular applications.
{"title":"Advancements and applications of wind tunnel testing in aerial vehicle development: A state-of-the-art overview","authors":"Durjoy Kumar Paul , Hasan Muhommod Robin , Nishitha Paul , Mim Mashrur Ahmed , Mahadi Hasan Masud","doi":"10.1016/j.jestch.2025.102244","DOIUrl":"10.1016/j.jestch.2025.102244","url":null,"abstract":"<div><div>Wind tunnel testing of aerial vehicles is a crucial step prior to the commercialization of vehicles. This paper focuses on an overview of common wind tunnel testing methods for various aerial vehicles with detailed specifications and flow conditions inside the wind tunnels. This work begins with the classification of wind tunnels and overviewing their evolution over the years. Later, wind tunnel specifications for testing scaled-down models of aerial vehicles and commercial models were discussed, along with the associated challenges and limitations. Literature reveals that challenges associated with the scaling of aerial vehicles, as well as cost, time, and technological limitations, need to be addressed to increase the accuracy of the wind tunnel testing. Lastly, this work summarizes the key specifications of the wind tunnels individually for different types of aerial vehicles, which will be beneficial for the researchers while selecting the suitable wind tunnel with desired specifications for particular applications.</div></div>","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"72 ","pages":"Article 102244"},"PeriodicalIF":5.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This article describes a unified DC-AC microgrid system based on photovoltaic PV batteries that offers coordinated parallel inverter operation in both grid-following and autonomous modes of operation. The developed system is intended to transition seamlessly between these operating modes to create the required enhancement in power quality PQ, reactive power support, utility needs, and local load demand. A dual-controller strategy is employed to allow realization of these features. In the grid-following mode, dual-tree complex wavelet transform (2TCWT) is coupled with DC-link voltage regulation and maximum power-based current control for properly executing real and reactive power operation. A synchronous reference frame SRF-based voltage control scheme is utilized to guarantee steady operation and voltage regulation among parallel inverters in the autonomous mode. On the other hand, to ensure the gridded performance and reliable operation, a hybrid islanding detection (HID) method is applied. The system combines a robust notch filter (NF) and a rate of change of frequency (ROCOF)-based phase-locked loop PLL which have good performance in grid monitoring, fast disturbance recognition, and resynchronization. The proposed HID method is in accordance with IEEE 2030.7 standards, thereby ensuring compliance with practical implementation requirements. The performance of the proposed unified microgrid architecture is validated by performing detailed simulation studies and experimental evaluation on the PV battery in a lab-scale prototype. Various operating scenarios, including grid-connected, islanded, and transition conditions were tested to prove the robustness of the design. The results confirm that coordinated parallel inverter operation improves power quality and reactive power support while guaranteeing seamless resynchronization and reliable autonomous operation. The extensive software-hardware validation reinforces the proof of concept and demonstrates the ready applicability of the DC-AC unified microgrid system toward future resilient energy networks.
{"title":"Coordinated dual-mode inverter control with NF–ROCOF-based islanding detection for enhanced power quality and seamless transition in DC–AC hybrid microgrids","authors":"Buddhadeva Sahoo , Mohit Bajaj , Vojtech Blazek , Lukas Prokop","doi":"10.1016/j.jestch.2025.102229","DOIUrl":"10.1016/j.jestch.2025.102229","url":null,"abstract":"<div><div>This article describes a unified DC-AC microgrid system based on photovoltaic PV batteries that offers coordinated parallel inverter operation in both grid-following and autonomous modes of operation. The developed system is intended to transition seamlessly between these operating modes to create the required enhancement in power quality PQ, reactive power support, utility needs, and local load demand. A dual-controller strategy is employed to allow realization of these features. In the grid-following mode, dual-tree complex wavelet transform (2TCWT) is coupled with DC-link voltage regulation and maximum power-based current control for properly executing real and reactive power operation. A synchronous reference frame SRF-based voltage control scheme is utilized to guarantee steady operation and voltage regulation among parallel inverters in the autonomous mode. On the other hand, to ensure the gridded performance and reliable operation, a hybrid islanding detection (HID) method is applied. The system combines a robust notch filter (NF) and a rate of change of frequency (ROCOF)-based phase-locked loop PLL which have good performance in grid monitoring, fast disturbance recognition, and resynchronization. The proposed HID method is in accordance with IEEE 2030.7 standards, thereby ensuring compliance with practical implementation requirements. The performance of the proposed unified microgrid architecture is validated by performing detailed simulation studies and experimental evaluation on the PV battery in a lab-scale prototype. Various operating scenarios, including grid-connected, islanded, and transition conditions were tested to prove the robustness of the design. The results confirm that coordinated parallel inverter operation improves power quality and reactive power support while guaranteeing seamless resynchronization and reliable autonomous operation. The extensive software-hardware validation reinforces the proof of concept and demonstrates the ready applicability of the DC-AC unified microgrid system toward future resilient energy networks.</div></div>","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"72 ","pages":"Article 102229"},"PeriodicalIF":5.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145475333","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-11-10DOI: 10.1016/j.jestch.2025.102228
Touhid Ahmed Orvi , Ismail Hossain , Mumit Hassan
Aerodynamic efficiency is fundamentally limited by flow separation at moderate angles of attack, where boundary layer detachment precipitates lift degradation and drag augmentation. In response to growing energy imperatives, this investigation advances passive flow control methodologies through systematic analysis of surface-modified symmetrical airfoils. This study examines a modified NACA 0015 airfoil incorporating indentations at five discrete chordwise positions along the lower surface. Through ANSYS CFD simulations employing the k-ω SST turbulence model, this work systematically evaluates aerodynamic performance variations of lower surface dimple modified airfoil across multiple angles of attack and chordwise locations. Results reveal that strategically positioned dimples profoundly influence aerodynamic efficiency, with 70 % chord position yielding 13.5 % greater lift-to-drag ratio at 7° AoA. While trailing-edge dimples (90 % chord) improve high-angle performance (7.25 % L/D increase at 10° AoA), this benefit is offset by 16.86 % degradation at 4° AoA. The optimal lift-to-drag ratio for 70 % chord length at 7° AoA is attributed to delayed flow separation, corroborated by static pressure contour analysis. Experimental validation via wind tunnel testing at 3 m/s further substantiates these computational finding. This study contributes to the rather underexplored arena of the lower surface modified dimples providing systematic evidence that these modifications can concurrently enhance lift and mitigate drag. The findings consolidate dimple engineering as a viable zero-energy solution for separation control.
{"title":"Computational and experimental investigation of lower-surface dimple effects on NACA 0015 airfoil aerodynamics","authors":"Touhid Ahmed Orvi , Ismail Hossain , Mumit Hassan","doi":"10.1016/j.jestch.2025.102228","DOIUrl":"10.1016/j.jestch.2025.102228","url":null,"abstract":"<div><div>Aerodynamic efficiency is fundamentally limited by flow separation at moderate angles of attack, where boundary layer detachment precipitates lift degradation and drag augmentation. In response to growing energy imperatives, this investigation advances passive flow control methodologies through systematic analysis of surface-modified symmetrical airfoils. This study examines a modified NACA 0015 airfoil incorporating indentations at five discrete chordwise positions along the lower surface. Through ANSYS CFD simulations employing the k-ω SST turbulence model, this work systematically evaluates aerodynamic performance variations of lower surface dimple modified airfoil across multiple angles of attack and chordwise locations. Results reveal that strategically positioned dimples profoundly influence aerodynamic efficiency, with 70 % chord position yielding 13.5 % greater lift-to-drag ratio at 7° AoA. While trailing-edge dimples (90 % chord) improve high-angle performance (7.25 % L/D increase at 10° AoA), this benefit is offset by 16.86 % degradation at 4° AoA. The optimal lift-to-drag ratio for 70 % chord length at 7° AoA is attributed to delayed flow separation, corroborated by static pressure contour analysis. Experimental validation via wind tunnel testing at 3 m/s further substantiates these computational finding. This study contributes to the rather underexplored arena of the lower surface modified dimples providing systematic evidence that these modifications can concurrently enhance lift and mitigate drag. The findings consolidate dimple engineering as a viable zero-energy solution for separation control.</div></div>","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"72 ","pages":"Article 102228"},"PeriodicalIF":5.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145529361","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-10-25DOI: 10.1016/j.jestch.2025.102209
Aqsa Razzaq , T. Hayat , Sajjad Shaukat Jamal , Sohail A. Khan , Aneeta Razaq
Nanotechnology has significant applications in various fields like nuclear reactor, paper production, metal spinning, heat transport and storage devices, power generation, renewable energy and many others. Hybrid nanomaterial in comparison to classical nanoliquid is impressive to enhance thermal transport rate. Hybrid nanoliquid has significant role in various applications using their innovative characteristics to develop performance, efficiency, functionality and stability in various industrial, engineering and scientific processes. Present communication addresses three-dimensional magnetohydrodynamic (MHD) flow of hybrid nanofluid in rotating frame. Flow is constructed to scrutinize thermal transport characteristics of hybrid nanoliquid and nanoliquid. Here manganese nickel zinc ferrite and zinc ferrite are employed as the nanoparticles. Engine oil is used as conventional liquid. Non-linear thermal radiation and non-uniform heat source/sink features are discussed. Thermal expression consists of non-uniform heat source/sink, magnetohydrodynamics and non-linear radiation. Entropy generation rate in presence of non-uniform heat source/sink is discussed. Related non-linear expressions of proposed model are converted into dimensionless systems through adequate transformations. Resultant non-linear ordinary systems are computed for numerical solutions through utilizing ND-solve technique. Graphical features for velocity, rate of entropy and temperature for influential variables regarding both nanoliquid and hybrid nanoliquid are analyzed. Outcomes of quantities against pertinent variables for both fluids are graphically analyzed. Larger magnetic field leads to rise the entropy rate and thermal field, whereas decreasing impact for velocity is witnessed. Larger approximation of radiation intensify Nusselt number and entropy rate. Revers impact for Nusselt number and temperature through non-uniform heat source variable is witnessed. Here one can conclude that thermal transport rate and temperature distribution for hybrid nanoliquid is higher when compared with nanoliquid. Drag force coefficient of hybrid nanoliquid is more dominant than nanoliquid.
{"title":"A road map of 3D entropy generated rotating hybrid nanoliquid flow with nonlinear thermal radiation","authors":"Aqsa Razzaq , T. Hayat , Sajjad Shaukat Jamal , Sohail A. Khan , Aneeta Razaq","doi":"10.1016/j.jestch.2025.102209","DOIUrl":"10.1016/j.jestch.2025.102209","url":null,"abstract":"<div><div>Nanotechnology has significant applications in various fields like nuclear reactor, paper production, metal spinning, heat transport and storage devices, power generation, renewable energy and many others. Hybrid nanomaterial in comparison to classical nanoliquid is impressive to enhance thermal transport rate. Hybrid nanoliquid has significant role in various applications using their innovative characteristics to develop performance, efficiency, functionality and stability in various industrial, engineering and scientific processes. Present communication addresses three-dimensional magnetohydrodynamic (MHD) flow of hybrid nanofluid in rotating frame. Flow is constructed to scrutinize thermal transport characteristics of hybrid nanoliquid and nanoliquid. Here manganese nickel zinc ferrite and zinc ferrite are employed as the nanoparticles. Engine oil is used as conventional liquid. Non-linear thermal radiation and non-uniform heat source/sink features are discussed. Thermal expression consists of non-uniform heat source/sink, magnetohydrodynamics and non-linear radiation. Entropy generation rate in presence of non-uniform heat source/sink is discussed. Related non-linear expressions of proposed model are converted into dimensionless systems through adequate transformations. Resultant non-linear ordinary systems are computed for numerical solutions through utilizing ND-solve technique. Graphical features for velocity, rate of entropy and temperature for influential variables regarding both nanoliquid and hybrid nanoliquid are analyzed. Outcomes of quantities against pertinent variables for both fluids are graphically analyzed. Larger magnetic field leads to rise the entropy rate and thermal field, whereas decreasing impact for velocity is witnessed. Larger approximation of radiation intensify Nusselt number and entropy rate. Revers impact for Nusselt number and temperature through non-uniform heat source variable is witnessed. Here one can conclude that thermal transport rate and temperature distribution for hybrid nanoliquid is higher when compared with nanoliquid. Drag force coefficient of hybrid nanoliquid is more dominant than nanoliquid.</div></div>","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"72 ","pages":"Article 102209"},"PeriodicalIF":5.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145365716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-11-26DOI: 10.1016/j.jestch.2025.102232
Mohammad Shariful Islam , Mohammad Abu Tareq Rony , Md Murad Hossain Sarker , Md. Khairul Bashar Bhuiyan , Md Saib , Md. Aktarujjaman , Md Shahab Uddin , Abeer D. Algarni , Ahmad Taher Azar , Walid El-Shafai
Visual Question Answering (VQA) is a fundamental challenge in multimodal AI, requiring models to integrate and reason over both visual and textual information. Despite advancements in deep learning, existing VQA models struggle with multi-step reasoning, hierarchical feature fusion, and multilingual generalization, limiting their effectiveness in real-world applications. This paper introduces MRAN-VQA, a Multimodal Recursive Attention Network for VQA, designed to address these limitations through a three-stage reasoning pipeline. The proposed approach first employs Recursive Attention Encoding, where a Vision Transformer (ViT) extracts visual features, and BERT-based embeddings encode textual information. A recursive self-attention mechanism iteratively refines these representations, improving contextual alignment. Hierarchical Feature Fusion integrates multi-level visual–text interactions through bilinear attention pooling and gated cross-modal operations. Finally, Answer Prediction with Attention Grounding applies a self-attentive reasoning module to responses while optimizing an Attention Grounding Score (AGS) for improved interpretability. Experiments on VQA v2.0, CLEVR, and our custom BanglaVQA datasets demonstrate that MRAN-VQA outperforms state-of-the-art models, achieving 75.6% accuracy on VQA v2.0, 96.1% on CLEVR, and 72% on BanglaVQA—notably surpassing transformer-based baselines. The model exhibits superior multi-step reasoning capabilities in compositional queries and significantly enhances performance in low-resource multilingual settings.
{"title":"MRAN-VQA: Multimodal Recursive Attention Network for Visual Question Answering","authors":"Mohammad Shariful Islam , Mohammad Abu Tareq Rony , Md Murad Hossain Sarker , Md. Khairul Bashar Bhuiyan , Md Saib , Md. Aktarujjaman , Md Shahab Uddin , Abeer D. Algarni , Ahmad Taher Azar , Walid El-Shafai","doi":"10.1016/j.jestch.2025.102232","DOIUrl":"10.1016/j.jestch.2025.102232","url":null,"abstract":"<div><div>Visual Question Answering (VQA) is a fundamental challenge in multimodal AI, requiring models to integrate and reason over both visual and textual information. Despite advancements in deep learning, existing VQA models struggle with multi-step reasoning, hierarchical feature fusion, and multilingual generalization, limiting their effectiveness in real-world applications. This paper introduces MRAN-VQA, a Multimodal Recursive Attention Network for VQA, designed to address these limitations through a three-stage reasoning pipeline. The proposed approach first employs Recursive Attention Encoding, where a Vision Transformer (ViT) extracts visual features, and BERT-based embeddings encode textual information. A recursive self-attention mechanism iteratively refines these representations, improving contextual alignment. Hierarchical Feature Fusion integrates multi-level visual–text interactions through bilinear attention pooling and gated cross-modal operations. Finally, Answer Prediction with Attention Grounding applies a self-attentive reasoning module to responses while optimizing an Attention Grounding Score (AGS) for improved interpretability. Experiments on VQA v2.0, CLEVR, and our custom BanglaVQA datasets demonstrate that MRAN-VQA outperforms state-of-the-art models, achieving 75.6% accuracy on VQA v2.0, 96.1% on CLEVR, and 72% on BanglaVQA—notably surpassing transformer-based baselines. The model exhibits superior multi-step reasoning capabilities in compositional queries and significantly enhances performance in low-resource multilingual settings.</div></div>","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"72 ","pages":"Article 102232"},"PeriodicalIF":5.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145623598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-11-29DOI: 10.1016/j.jestch.2025.102236
Serdar Çiftçi
Low-light image enhancement (LLIE) is a fundamental preprocessing task in computer vision which is essential for enhancing the quality and visibility of images that are captured under poor illumination. Traditional LLIE methods have lower computational costs but often lack to maintain natural tone distributions. In contrast, deep learning-based LLIE methods produce high-quality results at the cost of complex computations and significant training resources. This study introduces Autoencoder-Based Histogram Matching (AEHM), a hybrid LLIE framework that combines the effectiveness of the conventional histogram matching method with the representational capability of autoencoders. In AEHM, a pre-trained autoencoder predicts an optimal reference histogram from the low-light input image histogram, which is then used to perform histogram matching. Experiments conducted on multiple benchmark datasets demonstrate that AEHM outperforms traditional methods and delivers performance comparable to deep learning-based methods, while operating at a fraction of their computational costs, as measured by FLOPs. In particular, AEHM yields average improvements of about 2–3.5 dB in PSNR and 8%–12% in SSIM, together with a 30%–45% reduction in LPIPS, demonstrating its effectiveness in enhancing visual quality while preserving structural and perceptual fidelity.
{"title":"Low-light image enhancement using autoencoder-based histogram matching","authors":"Serdar Çiftçi","doi":"10.1016/j.jestch.2025.102236","DOIUrl":"10.1016/j.jestch.2025.102236","url":null,"abstract":"<div><div>Low-light image enhancement (LLIE) is a fundamental preprocessing task in computer vision which is essential for enhancing the quality and visibility of images that are captured under poor illumination. Traditional LLIE methods have lower computational costs but often lack to maintain natural tone distributions. In contrast, deep learning-based LLIE methods produce high-quality results at the cost of complex computations and significant training resources. This study introduces Autoencoder-Based Histogram Matching (AEHM), a hybrid LLIE framework that combines the effectiveness of the conventional histogram matching method with the representational capability of autoencoders. In AEHM, a pre-trained autoencoder predicts an optimal reference histogram from the low-light input image histogram, which is then used to perform histogram matching. Experiments conducted on multiple benchmark datasets demonstrate that AEHM outperforms traditional methods and delivers performance comparable to deep learning-based methods, while operating at a fraction of their computational costs, as measured by FLOPs. In particular, AEHM yields average improvements of about 2–3.5 dB in PSNR and 8%–12% in SSIM, together with a 30%–45% reduction in LPIPS, demonstrating its effectiveness in enhancing visual quality while preserving structural and perceptual fidelity.</div></div>","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"72 ","pages":"Article 102236"},"PeriodicalIF":5.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145623600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-11-24DOI: 10.1016/j.jestch.2025.102235
Dat Tien Nguyen , Keunsik No , Chang Won Jung
A hybrid window structure integrated with metal mesh films (MMFs) is proposed for electromagnetic pulse (EMP) protection in both civilian and military applications. The structure operates over an ultra-wide frequency range from 0.18 to 18 GHz. To the best of our knowledge, research on EMP-shielding windows remains limited in terms of frequency coverage, shielding effectiveness (SE), and optical transparency (OT), with most studies focusing on electromagnetic interference (EMI) shielding windows that achieve SE < 80 dB. This work presents four EMP shielding window configurations, each achieving SE > 80 dB and incorporating, for the first time, an asymmetric hexagonal mesh design. The metal mesh, deposited on a transparent dielectric substrate, exhibits OT of 75.5 % and a sheet resistance of 0.1 Ω/□. Compared to conventional square and symmetric hexagonal meshes, the asymmetric mesh improves SE by up to 4.7 dB at 10 GHz, with only a slight reduction in OT of about 3 %, demonstrating a superior balance between electromagnetic performance and transparency. Four window configurations are examined through both simulation and measurement, with square meshes from our previous work included for comparison. For civilian applications, double-pane glass with two MMF layers achieves average SE above 60 dB while maintaining OT over 40 %. For military applications, three-layer structures reach SE up to 90 dB with OT above 30 %. These results confirm that the proposed configurations provide broadband EMP shielding with sufficient transparency, offering a practical and scalable solution for EMP SE windows.
{"title":"Ultra-wideband EMP-shielded glass windows using metal mesh films for civilian and military infrastructure","authors":"Dat Tien Nguyen , Keunsik No , Chang Won Jung","doi":"10.1016/j.jestch.2025.102235","DOIUrl":"10.1016/j.jestch.2025.102235","url":null,"abstract":"<div><div>A hybrid window structure integrated with metal mesh films (MMFs) is proposed for electromagnetic pulse (EMP) protection in both civilian and military applications. The structure operates over an ultra-wide frequency range from 0.18 to 18 GHz. To the best of our knowledge, research on EMP-shielding windows remains limited in terms of frequency coverage, shielding effectiveness (SE), and optical transparency (OT), with most studies focusing on electromagnetic interference (EMI) shielding windows that achieve SE < 80 dB. This work presents four EMP shielding window configurations, each achieving SE > 80 dB and incorporating, for the first time, an asymmetric hexagonal mesh design. The metal mesh, deposited on a transparent dielectric substrate, exhibits OT of 75.5 % and a sheet resistance of 0.1 Ω/□. Compared to conventional square and symmetric hexagonal meshes, the asymmetric mesh improves SE by up to 4.7 dB at 10 GHz, with only a slight reduction in OT of about 3 %, demonstrating a superior balance between electromagnetic performance and transparency. Four window configurations are examined through both simulation and measurement, with square meshes from our previous work included for comparison. For civilian applications, double-pane glass with two MMF layers achieves average SE above 60 dB while maintaining OT over 40 %. For military applications, three-layer structures reach SE up to 90 dB with OT above 30 %. These results confirm that the proposed configurations provide broadband EMP shielding with sufficient transparency, offering a practical and scalable solution for EMP SE windows.</div></div>","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"72 ","pages":"Article 102235"},"PeriodicalIF":5.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145623662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-11-17DOI: 10.1016/j.jestch.2025.102234
Osama A. Gaheen , M.A. Aziz , Ernesto Benini , Mostafa E.A. Elsayed , Mostafa R. Rashed , Haitham Elshimy
This study investigates the dynamic response and performance of a hydraulic motor operating under controlled pulsating flow conditions. An experimental setup was developed incorporating a variable frequency pulse generator within an electro-hydraulic control circuit. Tests were conducted at inlet pressures of 20, 40, and 60 bar and pulsation frequencies of 2, 4, and 6 Hz. The results revealed that increasing flow pulsation frequency from 0 to 6 Hz significantly enhanced motor performance. At 60 bar, the motor speed increased from 71 RPM at 2 Hz to 114 RPM at 6 Hz, while torque rose from 6.11 kNm to 7.07 kNm. Similarly, increasing inlet pressure from 20 to 60 bar at 6 Hz improved speed from 67 to 114 RPM and torque from 3.65 to 7.07 kNm. At lower operating conditions (20 bar and 2 Hz), speed and pressure decreased by 60.74 % and 15 %, respectively, confirming the high sensitivity of motor output to pulsation parameters. Simulation results using Automation Studio closely matched the experimental findings, particularly at moderate frequencies and pressures with less than 4 % error. The developed empirical correlations accurately predicted motor speed and torque, with maximum deviations of ±10.49 %. The results demonstrate that controlling pulsation frequency provides an effective means of optimizing hydraulic motor performance, enhancing energy efficiency, and enabling dynamic regulation of speed and torque.
{"title":"Experimental and modeled response of hydraulic motors under pulsating flow","authors":"Osama A. Gaheen , M.A. Aziz , Ernesto Benini , Mostafa E.A. Elsayed , Mostafa R. Rashed , Haitham Elshimy","doi":"10.1016/j.jestch.2025.102234","DOIUrl":"10.1016/j.jestch.2025.102234","url":null,"abstract":"<div><div>This study investigates the dynamic response and performance of a hydraulic motor operating under controlled pulsating flow conditions. An experimental setup was developed incorporating a variable frequency pulse generator within an electro-hydraulic control circuit. Tests were conducted at inlet pressures of 20, 40, and 60 bar and pulsation frequencies of 2, 4, and 6 Hz. The results revealed that increasing flow pulsation frequency from 0 to 6 Hz significantly enhanced motor performance. At 60 bar, the motor speed increased from 71 RPM at 2 Hz to 114 RPM at 6 Hz, while torque rose from 6.11 kNm to 7.07 kNm. Similarly, increasing inlet pressure from 20 to 60 bar at 6 Hz improved speed from 67 to 114 RPM and torque from 3.65 to 7.07 kNm. At lower operating conditions (20 bar and 2 Hz), speed and pressure decreased by 60.74 % and 15 %, respectively, confirming the high sensitivity of motor output to pulsation parameters. Simulation results using <em>Automation Studio</em> closely matched the experimental findings, particularly at moderate frequencies and pressures with less than 4 % error. The developed empirical correlations accurately predicted motor speed and torque, with maximum deviations of ±10.49 %. The results demonstrate that controlling pulsation frequency provides an effective means of optimizing hydraulic motor performance, enhancing energy efficiency, and enabling dynamic regulation of speed and torque.</div></div>","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"72 ","pages":"Article 102234"},"PeriodicalIF":5.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145579399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-10-29DOI: 10.1016/j.jestch.2025.102212
Atakan Daşdemir, Humar Kahramanlı Örnek
Accurate prediction of epileptic seizures is important for patient safety and quality of life. This study aims to provide a fair, protocol-controlled comparison of two fusion strategies for EEG-based seizure prediction and to quantify their practical trade-offs. The decision-level pipeline combines posterior probabilities from two independently trained branches: a raw-EEG TCN → GRU with temporal attention model and an STFT-based 2D-CNN → GRU with temporal attention model. Fusion uses a simple calibrated type-2 rule tuned on validation data, and operating thresholds are set by Youden’s J. The feature-level pipeline uses the same two encoders—raw-EEG TCN → GRU and STFT-based 2D-CNN → GRU with temporal attention—to extract embeddings, which are then merged by a lightweight learnable fusion block before the final classifier. All networks are trained from scratch. Evaluation is conducted on the CHB-MIT dataset with stratified 5-fold cross-validation, reporting class-imbalance–robust metrics (PR-AUC and sensitivity at 5 % false-positive rate) in addition to ROC-AUC. The decision-level model attains accuracy 97.50 %, sensitivity 96.86 %, precision 97.57 %, F1 97.33 %, specificity 97.43 %, and AUC 0.99, with PR-AUC 0.994 and Sens@5%FPR 0.967. The feature-level model achieves accuracy 97.70 %, sensitivity 96.64 %, precision 98.47 %, F1 97.44 %, specificity 98.62 %, and AUC 0.99, with PR-AUC 0.995 and Sens@5%FPR 0.986. Post-hoc temperature scaling improved probability calibration (e.g., NLL from 0.089 → 0.083 at decision-level and 0.077 → 0.067 at feature-level) without affecting discrimination. An ablation with non-linear descriptors (Higuchi fractal dimension and fuzzy entropy) yielded modest average gains with added computational cost. These results delineate the conditions under which late posterior fusion versus early representational fusion is preferable and indicate that calibrated fusion improves robustness under realistic class imbalance.
{"title":"Epileptic seizure prediction with deep learning-based fusion methods","authors":"Atakan Daşdemir, Humar Kahramanlı Örnek","doi":"10.1016/j.jestch.2025.102212","DOIUrl":"10.1016/j.jestch.2025.102212","url":null,"abstract":"<div><div>Accurate prediction of epileptic seizures is important for patient safety and quality of life. This study aims to provide a fair, protocol-controlled comparison of two fusion strategies for EEG-based seizure prediction and to quantify their practical trade-offs. The decision-level pipeline combines posterior probabilities from two independently trained branches: a raw-EEG TCN → GRU with temporal attention model and an STFT-based 2D-CNN → GRU with temporal attention model. Fusion uses a simple calibrated type-2 rule tuned on validation data, and operating thresholds are set by Youden’s J. The feature-level pipeline uses the same two encoders—raw-EEG TCN → GRU and STFT-based 2D-CNN → GRU with temporal attention—to extract embeddings, which are then merged by a lightweight learnable fusion block before the final classifier. All networks are trained from scratch. Evaluation is conducted on the CHB-MIT dataset with stratified 5-fold cross-validation, reporting class-imbalance–robust metrics (PR-AUC and sensitivity at 5 % false-positive rate) in addition to ROC-AUC. The decision-level model attains accuracy 97.50 %, sensitivity 96.86 %, precision 97.57 %, F1 97.33 %, specificity 97.43 %, and AUC 0.99, with PR-AUC 0.994 and Sens@5%FPR 0.967. The feature-level model achieves accuracy 97.70 %, sensitivity 96.64 %, precision 98.47 %, F1 97.44 %, specificity 98.62 %, and AUC 0.99, with PR-AUC 0.995 and Sens@5%FPR 0.986. Post-hoc temperature scaling improved probability calibration (e.g., NLL from 0.089 → 0.083 at decision-level and 0.077 → 0.067 at feature-level) without affecting discrimination. An ablation with non-linear descriptors (Higuchi fractal dimension and fuzzy entropy) yielded modest average gains with added computational cost. These results delineate the conditions under which late posterior fusion versus early representational fusion is preferable and indicate that calibrated fusion improves robustness under realistic class imbalance.</div></div>","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"72 ","pages":"Article 102212"},"PeriodicalIF":5.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145425508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-12-01Epub Date: 2025-10-31DOI: 10.1016/j.jestch.2025.102222
Muhammad Rizwan Chughtai , Muhammad Latif Anjum , Iftikhar Ahmad , Muddesar Iqbal , Dhafer Almakhles , Mahmoud Abdelrahim
This paper is concerned with the design of trajectory tracking control techniques for quadcopters. An optimized control law, specifically a PID-based integral super-twisting sliding mode control, is proposed to achieve precise tracking of attitude, heading, position, and altitude. A nonlinear dynamic model of the quadcopter, accounting for gyroscopic moments and aerodynamic forces, is formulated using the Euler–Lagrange method. To enhance performance, genetic algorithm is employed to optimize the controller gains. The stability analysis is then carried out using Lyapunov function candidates. The effectiveness of the proposed method is evaluated through numerical simulations of the drone model based on various performance metrics for a 3D-helical trajectory. The simulation results demonstrate that the proposed approach outperforms existing techniques and achieves improved trajectory tracking accuracy. The controller is further validated using controller-in-the-loop testing, demonstrating its effectiveness in practical scenarios.
{"title":"Trajectory tracking control design for quadcopter based on optimized integral super-twisting sliding mode technique","authors":"Muhammad Rizwan Chughtai , Muhammad Latif Anjum , Iftikhar Ahmad , Muddesar Iqbal , Dhafer Almakhles , Mahmoud Abdelrahim","doi":"10.1016/j.jestch.2025.102222","DOIUrl":"10.1016/j.jestch.2025.102222","url":null,"abstract":"<div><div>This paper is concerned with the design of trajectory tracking control techniques for quadcopters. An optimized control law, specifically a PID-based integral super-twisting sliding mode control, is proposed to achieve precise tracking of attitude, heading, position, and altitude. A nonlinear dynamic model of the quadcopter, accounting for gyroscopic moments and aerodynamic forces, is formulated using the Euler–Lagrange method. To enhance performance, genetic algorithm is employed to optimize the controller gains. The stability analysis is then carried out using Lyapunov function candidates. The effectiveness of the proposed method is evaluated through numerical simulations of the drone model based on various performance metrics for a 3D-helical trajectory. The simulation results demonstrate that the proposed approach outperforms existing techniques and achieves improved trajectory tracking accuracy. The controller is further validated using controller-in-the-loop testing, demonstrating its effectiveness in practical scenarios.</div></div>","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"72 ","pages":"Article 102222"},"PeriodicalIF":5.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145425509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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