en jalali 1404 10 1 gregorian 2026 1 1 22 1 online 1 fulltext

en This study presents a comprehensive experimental investigation into the hydrodynamic performance of high-speed planning vessels equipped with adjustable trim tabs. Two scaled 40-foot beam-type models were tested under controlled towing tank conditions to assess the effects of trim angle variations on resistance, dynamic stability, and transition into the planning regime. The tests evaluated both untrimmed and trimmed configurations using multiple trim tab heights, measuring resistance forces, trim behavior, and planning onset velocities. Results demonstrate that optimal trim tab deployment significantly reduces hydrodynamic resistance, lowers the Hump Resistance Region, and enhances vessel stability at critical speeds. Trim tab configuration “B” showed superior performance, enabling earlier planning transition with lower power demand and reduced bow impact. Additionally, this study addresses model scaling effects, construction tolerances, and control system calibration to ensure fidelity with full-scale vessel behavior. The findings underscore the importance of trim tab integration in the design of modern high-speed vessels, offering practical insights for resistance minimization, propulsion efficiency, and structural safety in dynamic marine environments.   High-speed vessels,Trim tab optimization,Hydrodynamic resistance,Planing performance,Experimental model testing,Towing tank analysis,Beam-type hulls,Resistance reduction,Trim angle effects,Marine propulsion efficiency 1 13 http://ijmt.ir/browse.php?a_code=A-10-8180-7&slc_lang=en&sid=1 2025/06/2 1404/3/12 2025/09/28 1404/7/6 Seyed Reza Samaei Assistant professor, Department of Civil Engineering, SR.C., Islamic Azad University, Tehran, Iran samaei@srbiau.ac.ir 0031947532846004560 0031947532846004560 No Mohammad Asadian Ghahfarokhi Assistant professor, Department of Civil Engineering, SR.C., Islamic Azad University, Tehran, Iran; m.asadian@srbiau.ac.ir 0031947532846004561 0031947532846004561 Yes

en Internal corrosion poses a significant risk to offshore pipeline operations. This study aims to utilize a combination of the Finite Element Method (FEM) and Latin Hypercube Sampling (LHS) to create a database of structural response data for corroded pipelines experiencing longitudinally interacting internal corrosion defects under internal and external pressure loading. The database includes input data such as pipeline geometry parameters, pipeline material data, corrosion defect data and loading data. This generated database will be utilized to train various advanced machine learning (ML) models to develop a predictive model capable of estimating the Maximum von Mises Stress occurring in the outermost mesh layer of a mesh ligament within the thickness of the corroded pipeline at the defected area. Such predictive capabilities of the ML model will enhance the ability to forecast leakage based on pipeline and defect specifications, thereby saving costs and time. To achieve the optimal model, various ML algorithms have been compared. Finally, to assess the prediction accuracy of the models, results of models were compared and evaluated.   Offshore Pipeline Engineering,Pipeline Integrity Management,Structural Reliability,Random Sampling,Latin Hypercube Sampling,Machine Learning 14 31 http://ijmt.ir/browse.php?a_code=A-10-8417-1&slc_lang=en&sid=1 2025/06/22025/08/19 1404/5/28 2025/09/282025/10/8 1404/7/16 Soheyl Hosseinzadeh University of Tehran s_hosseinzadeh@ut.ac.ir 0031947532846004562 0031947532846004562 Yes Mohammad Reza Bahaari University of Tehran mbahari@ut.ac.ir 0031947532846004563 0031947532846004563 No Mohsen Abayni University of Tehran mohsen.abyani@ut.ac.ir 0031947532846004564 0031947532846004564 No

en Qeshm Island’s extreme aridity and rapid growth expose a mismatch between headline per-capita renewable water figures and actual aquifer stress. Using multi-decadal precipitation, census, and well records, we estimate renewable supply, recharge, storage, and salinity. Natural replenishment is minimal: about 60% of rainfall is lost to evaporation and most of the remainder leaves as runoff, yielding little effective recharge. Under trend-based demographic projections, renewable water per capita declines to 757 m3 per person per year by 2036 (medium evaporation-loss scenario). Groundwater observations show a long-term water-table decline near 0.091 m per year and salinity rising to about 14 to 16.6 dS/m, consistent with persistent overdraft and seawater intrusion or up-coning. To translate hydrologic limits into development choices, we evaluate a conservative 40% withdrawal of renewable yield with a mixed allocation 70% agriculture, 20% industry, 10% domestic. At this intensity the budget can irrigate about 1,523 ha of date palms, support roughly 335,000 t/yr of petrochemical output, and supply about 23,841 residents, generating approximately $16.45 million (agriculture), $334.69 million (industry), and $0.22 million (domestic) per year around $351 million in total. These results show that per-capita indicators alone can overstate security; resilient coastal-marine development on Qeshm will require aligning withdrawals with limited renewability and storage, coupled with managed aquifer recharge, targeted desalination, and selective use of saline groundwater to protect potable supplies and industrial applications requiring low-salinity makeup water (e.g., boiler and cooling systems), where acceptable conductivity is typically ≲0.2–2 dS m⁻¹ with low hardness and silica. Groundwater Overdraft,Qeshm Island Aquifer,Renewable Water per Capita (RWRPC),Salinization,Water Scarcity Management 32 47 http://ijmt.ir/browse.php?a_code=A-10-7545-1&slc_lang=en&sid=1 2025/06/22025/08/192025/08/22 1404/5/31 2025/09/282025/10/82025/11/15 1404/8/24 Emad Mahjoobi Department of Water and Environmental Engineering, Faculty of Civil Engineering, Shahrood University of Technology emahjoobi@shahroodut.ac.ir 0031947532846004532 0031947532846004532 Yes Mahan Azizi PhD student in Water Resources Engineering and Management, Faculty of Civil Engineering,Shahrood University of Technology mahan.azizi@shahroodut.ac.ir 0031947532846004533 0031947532846004533 No Mohammad Reza Asli Charandabi PhD student in Water Resources Engineering and Management, Faculty of Civil Engineering,Shahrood University of Technology m.aslicharandabi@shahroodut.ac.ir 0031947532846004534 0031947532846004534 No

en The reliable control of marine vessels remains a critical challenge due to the nonlinear dynamics and strong environmental disturbances inherent in ocean operations. This paper proposes an optimal heading control strategy for a linearized model of a high-speed container ship based on a Proportional–Integral–Derivative (PID) controller whose parameters are tuned using the Adaptive Particle Swarm Optimization (APSO) algorithm. While classical PID controllers are widely adopted for their structural simplicity and robustness, they often require labor-intensive parameter tuning and exhibit performance degradation under time-varying sea states. To overcome these limitations, the proposed APSO framework adaptively balances global exploration and local exploitation to identify optimal PID gains. The optimization objective function integrates both trajectory-tracking accuracy and control effort, thereby ensuring a trade-off between precision and efficiency. The linear dynamic model of the container ship is formulated and implemented in MATLAB/Simulink, serving as the test platform. Simulation results reveal that the APSO-tuned PID controller achieves substantial improvements in transient and steady-state responses, including overshoot suppression, reduced settling time, and acceptable gain margin, compared with conventional PID tuning. These findings highlight the potential of APSO-based PID design as a robust and interpretable control solution for advanced marine navigation and dynamic positioning applications. Adaptive particle Swarm Optimization (APSO),Fixt Structure control,Robust Control,Optimal PID,a linearized model container ship 48 54 http://ijmt.ir/browse.php?a_code=A-10-8338-1&slc_lang=en&sid=1 2025/06/22025/08/192025/08/222025/06/4 1404/3/14 2025/09/282025/10/82025/11/152026/01/4 1404/10/14 Esmat Sadat Alaviyan Shahri Assistant Professor, Electrical and Computer Engineering Department, University of Gonabad, Gonabad, Iran; alaviyan@gonabad.ac.ir 0031947532846004565 0031947532846004565 Yes

en Wave Energy Converters (WECs) are devices designed to extract electricity from ocean waves. This study introduces a modular flap-type WEC in which a single flap is divided into two vertical segments. This modification aims to investigate its impact on power production. A dynamic model is developed for this dual-flap system, and the governing equations of motion of the system are derived. To account for the interaction between the flaps and the waves, hydrodynamic coefficients and excitation moments are computed using a Boundary Element Method (BEM), which takes the influence of wave-induced forces on each flap into consideration. The rotational motions of both flaps are then analyzed, with an assumption of regular waves. Furthermore, the power generated by each flap is calculated, based on their respective rotational responses. This analysis is aimed to evaluate the efficiency of the dual-flap configuration in harnessing wave energy. Wave Energy Converter )WEC(,vertical double flap,power,water wave,Oscillating Wave Surge Converter (OWSC) 55 65 http://ijmt.ir/browse.php?a_code=A-10-4-3&slc_lang=en&sid=1 2025/06/22025/08/192025/08/222025/06/42025/08/30 1404/6/8 2025/09/282025/10/82025/11/152026/01/42026/02/15 1404/11/26 Hamid Bab Marine Engineering , School of Mechanical Engineering , Sharif University of Technology hamid.bab@mech.sharif.edu 0031947532846004567 0031947532846004567 No Mahdi Aziminia Marine Engineering , School of Mechanical Engineering , Sharif University of Technology mm_aziminia@mech.sharif.edu 0031947532846004568 0031947532846004568 No Abuzar Abazari Associate Professor Marine Engineering , Chabahar Maritime University, Chabahar, Iran abuzarabazari@cmu.ac.ir 0031947532846004569 0031947532846004569 No Mehdi Behzad Professor Mechanical Engineering , School of Mechanical Engineering , Sharif University of Technology m_behzad@sharif.edu 0031947532846004570 0031947532846004570 Yes

en In response to rising global energy demand and the urgent need to reduce greenhouse gas emissions, Offshore Wind Turbines (OWTs) have emerged as promising renewable energy solutions. Among deep-water support structures, semi-submersible platforms offer superior motion stability and design flexibility, but their high structural weight significantly affects construction and installation costs. This study compares five metaheuristic algorithms—Genetic Algorithm (GA), Ant Colony Optimization for Continuous Domains (ACOR), Artificial Bee Colony (ABC), Firefly Algorithm (FA), and Particle Swarm Optimization (PSO)—for weight optimization of a four-column semi-submersible substructure supporting a Vertical Axis Wind Turbine (VAWT) with hexagonal pontoons. The algorithms were first validated with a reference platform optimized using the Generalized Reduced Gradient (GRG) method. They were then applied to minimize the VAWT substructure weight by optimizing pontoon and column geometry, spacing, and draft under hydrostatic stability, motion, airgap, and feasibility constraints. Each algorithm was executed five times, and Kolmogorov–Smirnov tests confirmed normality of optimized weight and Number of Function Evaluations (NFE). Analysis of Variance (ANOVA) indicated statistically significant differences among algorithms, and the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) was used for multi-criteria decision-making, considering average weight, NFE, accuracy, variance, and stability. Results indicate that ACOR achieved the highest rank, achieving ~37.6% (3690 tons) weight reduction. The findings demonstrate ACOR’s effectiveness as a decision-support tool for conceptual design of semi-submersible substructure of OWTs. However, it is expected that hydrodynamic loading, aero-structural coupling to be also considered for further detailed design. Metaheuristic optimization,Semi-submersible VAWT,Statistical evaluation algorithm,Hexagonal pontoons,Multi-criteria decision 66 79 http://ijmt.ir/browse.php?a_code=A-10-31-1&slc_lang=en&sid=1 2025/06/22025/08/192025/08/222025/06/42025/08/302026/01/14 1404/10/24 2025/09/282025/10/82025/11/152026/01/42026/02/152026/02/18 1404/11/29 Zanyar Delgarm Sahand Univ. of Tech. zanyardelgarm@gmail.com 0031947532846004571 0031947532846004571 No Ahmad Reza Mostafa Gharebaghi Sahand University of Technology mgharabaghi@sut.ac.ir 0031947532846004572 0031947532846004572 Yes Arefeh Emami Univ. of Hormozgan emami@hormozgan.ac.ir 0031947532846004573 0031947532846004573 No