Engineering Science and Technology-An International Journal-Jestech最新文献

{"title":"Experimental investigation of the effect of nano fluid use on heat transfer in unmanned aircraft cooling system with different types of wing geometry","authors":"Abdulsamed Güneş ,&nbsp;Beytullah Erdoğan ,&nbsp;Gülşah Çakmak","doi":"10.1016/j.jestch.2025.102059","DOIUrl":"10.1016/j.jestch.2025.102059","url":null,"abstract":"<div><div>Unmanned aerial vehicles (UAVs) have performed critical tasks such as air dominance, national security, wildlife surveillance, damage detection studies after natural disasters, early intervention in forest fires, management activities, explosions, and logistics. UAVs, which perform these critical tasks and whose importance has been increasing in the world in recent years, experience a loss of thermal efficiency in their cooling systems at critical times during flight. In order to optimize cooling mechanisms for UAVs, this study aims to redesign existing cooling fins. In addition, it is planned to use nanofluids instead of traditional coolants in these radiators. In addition to the increased cooling performance with the use of nanofluid, it has been determined that this effect is further increased by the use of new design parts (Radiator-F1, Radiator-F2, Radiator-F3) consisting of louver type fin structures with different fin geometries in number and pattern compared to standard flat fins (Radiator-S). In these newly designed cooling systems were tested at flow rates of 20 and 22 lt/min, a temperature of 70 °C, and an inlet pressure of 0.2 bar are focused on increasing the cooling efficiency of the coolers. Experiments were carried out on standard and newly designed radiators using Al₂O₃, ZnO and CuO nanofluids at 0.3 % volumetric concentration for thermal performance measurement. The heat transfer in Radiator-S using pure water was calculated as 9.02 kW. The heat transfer amount in the newly designed Radiator-F1 using pure water was the highest and increased by approximately 23 %. The heat transfer increase in Radiator-F1 using CuO nanofluid was the highest and was determined to be approximately 38 % compared to using pure water in Radiator-S. Thermal conductivity and viscosity ratios increased compared to pure water. The highest increase in thermal conductivity was approx 18 % in ZnO nanofluid and viscosity was approx 16 % in Al₂O₃ nanofluid.</div><div>The improvement resulting from the findings increases the operational capabilities of the (UAVs). In addition, the lightness resulting from a more compact system indirectly increases the flight duration. These results demonstrate significant improvements in cooling performance for UAV applications.</div></div>","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"65 ","pages":"Article 102059"},"PeriodicalIF":5.1,"publicationDate":"2025-04-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143776837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High-gain adaptive observer for floating voltages estimation and capacitor aging monitoring in multicell converters","authors":"Boukhalfa Nait Slimani ,&nbsp;Malek Ghanes ,&nbsp;Said Djennoune","doi":"10.1016/j.jestch.2025.102036","DOIUrl":"10.1016/j.jestch.2025.102036","url":null,"abstract":"<div><div>In multicell converters, capacitors play a critical role in energy management and voltage stabilization of each cell. They ensure balanced regulation of floating voltages and minimize energy losses during switch commutations. However, capacitor aging leads to increased dielectric losses, equivalent series resistance (ESR), and energy dissipation, which degrade the performance of the converter and increase the risk of failure. Consequently, effective monitoring of capacitor aging is essential. Moreover, in such converters, estimating the voltages across flying capacitors is crucial for the synthesis of most control laws. To address these dual issues, this paper proposes a high-gain adaptive observer capable of simultaneously estimating the parameters and state variables of multicell converters. This approach enables real-time monitoring of capacitor aging while estimating floating voltages. Novel hybrid dynamic models of the converter are introduced, incorporating equivalent series resistance and equivalent capacitance as parameters to be estimated to account for capacitor aging. The observer is designed to estimate the voltages of flying capacitors, the load resistance, and the dielectric loss resistance due to aging. Its design relies on a thorough analysis of the observability of states and parameters, which depends on the discrete states of the converter, and its stability is demonstrated using the Lyapunov approach. Numerical simulations performed on a three-cell converter demonstrate the effectiveness of the proposed observer in estimating the voltages of flying capacitors and simultaneously monitoring their health.</div></div>","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"65 ","pages":"Article 102036"},"PeriodicalIF":5.1,"publicationDate":"2025-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143776835","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Designing and analysis of flexible four legged-loaded metamaterial absorber sensor for permittivity detection of a solid substrate","authors":"Shihabun Sakib ,&nbsp;Mohammad Tariqul Islam ,&nbsp;Ahasanul Hoque ,&nbsp;Abdulmajeed M. Alenezi ,&nbsp;Mohamed S. Soliman ,&nbsp;Haitham Alsaif","doi":"10.1016/j.jestch.2025.102051","DOIUrl":"10.1016/j.jestch.2025.102051","url":null,"abstract":"<div><div>This article proposes a metamaterial absorber (MMA) based sensor with solid permittivity analysis. MMA application has received significant interest across multiple domains, including sensors, wireless communication, detectors, emitters, antenna design, and spatial light modulators. The suggested absorber consists of circular and rectangular split-ring resonators with an inner four-lagged loaded copper patch. This configuration is designed to produce a distinct resonance at 2.615 GHz. The associated absorption rate at this resonance is 99.98 %. The study involved the extraction and subsequent analysis of the complex values related to the permittivity, permeability, refractive index, and impedance of MMA. There is no significant change in reflection and transmission coefficients for 15° bends of array and unit cell, due to which the proposed MMA can be used for conformal applications. The validity of the sensor is analyzed by comparing between known and measured permittivity of the Roger substrate. The average and normalized sensitivity are 107.55 MHz and 4.113 %. The sample thickness is finalized from 0.4 to 1.4 mm on the basis of the reflection coefficient of the sensor shifted linearly towards lower frequency. Sample thickness analysis is crucial for any sensor model. However, most reported articles have unnoted this analysis. Additionally, the sensor is equipped with an un-metalized Roger RT5880 dielectric slab with nine 1.5 mm (diameter) holes. The holes caused Roger RT5880′s dielectric constant to change; the sensor effectively traced the change in the sample’s dielectric constant. Overall, the proposed material exhibits a high absorption efficiency, miniature size (29.4 × 29.4 mm²), low cost, simple structure, and can resist the environmental factors that cause cross-sensitivity, making it an attractive candidate for permittivity sensors for solid substrates.</div></div>","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"65 ","pages":"Article 102051"},"PeriodicalIF":5.1,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143739452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Novel distance-fitness learning scheme for ameliorating metaheuristic optimization","authors":"Emre Çelik ,&nbsp;Essam H. Houssein ,&nbsp;Mahmoud Abdel-Salam ,&nbsp;Diego Oliva ,&nbsp;Ghanshyam G. Tejani ,&nbsp;Nihat Öztürk ,&nbsp;Sunil Kumar Sharma ,&nbsp;Mohammed Baljon","doi":"10.1016/j.jestch.2025.102053","DOIUrl":"10.1016/j.jestch.2025.102053","url":null,"abstract":"<div><div>An important portion of metaheuristic algorithms is guided by the fittest solution obtained so far. Searching around the fittest solution is beneficial for speeding up convergence, but it is detrimental considering local minima stagnation and premature convergence. A novel distance-fitness learning (DFL) scheme that provides better searchability and greater diversity is proposed to resolve these. The method allows search agents in the population to actively learn from the fittest solution, the worst solution, and an optimum distance-fitness (ODF) candidate. This way, it aims at approaching both the fittest solution and ODF candidate while at the same time moving away from the worst solution. The effectiveness of our proposal is evaluated by integrating it with the reptile search algorithm (RSA), which is an interesting algorithm that is simple to code but suffers from stagnating in local minima, converging too early, and a lack of sufficient global searchability. Empirical results from solving 23 standard benchmark functions, 10 Congresses on Evolutionary Computation (CEC) 2020 test functions, and 2 real-world engineering problems reveal that DFL boosts the capability of RSA significantly. Further, the comparison of DFL-RSA with popular algorithms vividly signifies the potential and superiority of the method over most of the problems in terms of solution precision.</div></div>","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"65 ","pages":"Article 102053"},"PeriodicalIF":5.1,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143716280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of polarization potential on tribocorrosion behavior of duplex stainless steel UNS S32205 in NaCl solution","authors":"Jomar José Knaip Ribeiro ,&nbsp;Oriana Palma Calabokis ,&nbsp;Yamid Enrique Nuñez de la Rosa ,&nbsp;Silvio Francisco Brunatto ,&nbsp;Paulo César Borges","doi":"10.1016/j.jestch.2025.102047","DOIUrl":"10.1016/j.jestch.2025.102047","url":null,"abstract":"<div><div>This study explores the effects of anodic, cathodic, and open circuit (OCP) potentials on the tribocorrosion behaviour of the UNS S32205 duplex stainless steel, which is largely used in oil, gas, and cellulose industry. For this purpose, tribocorrosion assays using a contact sphere (Si₃N₄) against the specimen plane in reciprocating sliding movement in 0.5 M NaCl solution were carried out. For comparison purposes, cathodic polarization or tests without applied potential under distilled water (DW) were used to inhibit corrosion for tribocorrosion tests. Two main distinct behaviours were observed: i) high coefficients of friction and lower wear volumes at the cathodic polarization (CP) for conditions smaller or equal to –0.8 V (vs Ag/AgCl 3 M) as well as in DW; and ii) low coefficients of friction and higher wear volumes for anodic polarization (AP), OCP, and CP for –0.4 V. The tribocorrosion behaviour of both groups was directly related to the chemical characteristics inside the tracks analyzed using SEM-EDS and Raman spectroscopy. All analyzed tracks showed similar oxygen contents and chemical compositions within each group. Finally, this study allowed the determination of the great effect of the potential applied on the tribocorrosion behaviour and the identification of differences between the cathodic protection and distilled water assays as methods to inhibit corrosion.</div></div>","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"65 ","pages":"Article 102047"},"PeriodicalIF":5.1,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143716052","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sizing of interoperable EV charging stations on highways with a coordinated charging scheduling strategy","authors":"Ömer Gönül ,&nbsp;A.Can Duman ,&nbsp;Önder Güler","doi":"10.1016/j.jestch.2025.102035","DOIUrl":"10.1016/j.jestch.2025.102035","url":null,"abstract":"<div><div>Electric vehicle charging station (EVCS) sizing on highways poses unique challenges compared to urban areas due to the “charge-and-go” tendency of drivers, fewer and more distant stations, and higher charging demand. Unlike urban areas, where prolonged parking enables temporal load management, highways require dynamic spatial load distribution. Special strategies, such as coordinated charging and interoperability, enable efficient and cost-effective EVCS sizing for highways. Therefore, this study proposes a coordinated charging strategy for highway EVCS sizing, incorporating interoperability principles. Charging demand is managed through spatial load shifting and communication between interoperable EVCSs, efficiently utilizing available fast-charging sockets. If no sockets are available, EVs are directed to neighboring stations based on their remaining battery energy. Indirectly, this intelligent redistribution of demand minimizes grid overloads, enhancing system reliability. The method which is applied to Türkiye’s busiest highway reduces charging equipment requirements by 15.2%, significantly lowering initial investment costs. Moreover, spatially distributed charging reduces annual peak power demand by 22.2%, mitigating grid stress by balancing the load across the network. These results highlight the potential of incorporating coordinated charging in EVCS sizing to improve sustainability, feasibility, and scalability of EV infrastructure. This approach offers a replicable framework for tackling EVCS challenges on highways worldwide.</div></div>","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"65 ","pages":"Article 102035"},"PeriodicalIF":5.1,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143688019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of ballistic properties of densified reinforced laminated wood material","authors":"İlker Yalçın ,&nbsp;Raşit Esen","doi":"10.1016/j.jestch.2025.102032","DOIUrl":"10.1016/j.jestch.2025.102032","url":null,"abstract":"<div><div>The aims of this study is to determine the ballistic properties of densified, reinforced, and laminated wood material. For this purpose, the samples obtained from Uludağ Fir (Abies nordmanniana subsp. bornmülleriana mattf.) and black poplar (Populus nigra L.) woods were impregnated with melamine formaldehyde resin and then densified at 120 °C and 140 °C with 25 % and 50 % thermo-mechanical method, and the panels were prepared. Then, these panels were laminated using 3, 5, and 7 layers, fiberglass, and carbon fiber reinforcement materials. Ballistics tests were carried out following the NIJ 01010.06 standard. In addition, stereo microscope and SEM images were examined to determine the changes in the anatomical structure of the wood material after the densification treatment and the adhesion of the melamine formaldehyde and polyurethane resins to the wood material. As a result of the ballistic test, laminated materials did not provide protection. Afterward, 2 pieces of 5 and 1 piece of 3-layer laminated panels were produced for ballistics tests. Ballistic protection was obtained from fiberglass and carbon fiber reinforced, laminated materials obtained from Black poplar and Uludağ Fir wood materials, which are 50 % densified at 120 °C and 140 °C. It is recommended that the panels be reinforced with fiberglass and carbon fiber, and 50 % densified panels can be used indoors and outdoors where ballistic resistance is required.</div></div>","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"65 ","pages":"Article 102032"},"PeriodicalIF":5.1,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643466","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Towards enhanced photovoltaic Modeling: New single diode Model variants with nonlinear ideality factor dependence","authors":"Martin Ćalasan ,&nbsp;Snežana Vujošević ,&nbsp;Gojko Krunić","doi":"10.1016/j.jestch.2025.102037","DOIUrl":"10.1016/j.jestch.2025.102037","url":null,"abstract":"<div><div>The energy sector is increasingly challenged to transition to sustainable and renewable energy sources. Solar cells play a pivotal role in this process, enabling the direct conversion of solar energy into electricity. Traditional solar cell models, such as the single-diode model (SDM), often assume a constant diode ideality factor, despite research indicating its dependence on voltage. This study introduces five novel SDM variants that incorporate the nonlinear dependence of the diode ideality factor on voltage, aiming to improve the accuracy of current–voltage (I-V) characteristic modeling. For each of the proposed models, an analytical current–voltage relationship was derived using the Lambert W function, ensuring precise representation of the system’s behavior. Experimental validation was conducted on a standard solar cell (RTC France) and three commercial modules (MSX60, PWP201, KC200GT), demonstrating significant reductions in modeling errors (RMSE) compared to classical SDM, DDM, and TDM approaches. Furthermore, the analysis highlights the stable performance of the proposed models under varying conditions of insolation and temperature, confirming their robustness and practical applicability. This work provides an innovative framework for enhancing solar cell modeling, laying the foundation for future research and practical applications in optimizing photovoltaic systems.</div></div>","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"65 ","pages":"Article 102037"},"PeriodicalIF":5.1,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643141","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Front Matter 1 - Full Title Page (regular issues)/Special Issue Title page (special issues)","authors":"","doi":"10.1016/S2215-0986(25)00100-4","DOIUrl":"10.1016/S2215-0986(25)00100-4","url":null,"abstract":"","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"64 ","pages":"Article 102045"},"PeriodicalIF":5.1,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143642560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Huffman coding-based data reduction and quadristego logic for secure image steganography","authors":"Irsyad Fikriansyah Ramadhan ,&nbsp;Ntivuguruzwa Jean De La Croix ,&nbsp;Tohari Ahmad ,&nbsp;Andre Uzamurengera","doi":"10.1016/j.jestch.2025.102033","DOIUrl":"10.1016/j.jestch.2025.102033","url":null,"abstract":"<div><div>Ensuring secure data transmission is critical for maintaining confidentiality and has become increasingly important. Steganography, which embeds secret information within digital images, has been widely explored to safeguard sensitive data from unauthorized access over public networks. However, existing steganographic algorithms often face a significant trade-off between payload capacity, image quality, and security. Embedding large amounts of data can cause noticeable distortion in image quality, undermining the technique’s effectiveness. Furthermore, current methods lack adaptability to diverse cover media and struggle to maintain reversibility and high visual quality under increased embedding capacities. To address these challenges, this study proposes a novel steganographic algorithm integrating two key innovations: (1) Enhancement of stego image quality via stego image’s segmentation into four images, reducing concentration-induced distortions, and (2) optimization of data embedding through Huffman coding through a lossless compression minimizing the embedding-induced distortions while maximizing payload capacity. The experimental results show that the proposed method achieves high visual fidelity, with PSNR values ranging from 75.793 dB to 44.997 dB without encryption and from 51.159 dB to 44.316 dB with encryption for payloads between 10 KB and 100 KB. These values exceed the 30 dB threshold for acceptable image steganography, ensuring minimal perceptual distortion. Additionally, the SSIM remains consistently above 0.98, indicating strong structural preservation of stego images. Comparative analysis with existing methods confirms that the proposed approach outperforms in embedding capacity, structural similarity index measure (SSIM), and peak signal-to-noise ratio (PSNR), reflecting the stego images’ quality.</div></div>","PeriodicalId":48609,"journal":{"name":"Engineering Science and Technology-An International Journal-Jestech","volume":"65 ","pages":"Article 102033"},"PeriodicalIF":5.1,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143642162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}