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Ship Roll Analysis Using CFD-Derived Roll Damping:Numerical and Experimental Study

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Journal of Marine Science and Application 2022年第1期21卷 67-79页

作者： Isar Ghamari Hamid Reza Mahmoudi Ahmad Hajivand mohammad saeed seif Department of Marine Technology Norwegian University of Science and Technology(NTNU)TrondheimNorway Department of Mechanical Engineering Sharif University of TechnologyTehranIran Department of Marine Engineering Khorramshahr University of Marine Science and TechnologyKhorramshahrIran

This study investigates the roll decay of a fishing vessel by experiments and computational fluid dynamics(CFD)simulations.A fishing vessel roll decay is tested experimentally for different initial roll *** roll decay is also simulated numerically by CFD simulations and is validated against the experimental *** shows that the roll damping could be obtained by CFD with high level of *** linear and nonlinear damping terms are extracted from the CFD roll decay results and are used in a potential-based *** this way we are using a hybrid solver that benefits the accuracy of the CFD results in terms of roll damping estimation and the fast computations of the potential-based solver at the same *** hybrid method is used for reproducing the free roll decays at Fn=0 and also in analyzing some cases in *** experiments,CFD and the hybrid parts are described in *** is shown that the suggested method is capable of doing the simulations in a very short time with high level of *** strategy could be used for many seakeeping analyses.

关键词： Roll decay Computational fluid ynamics Experiments Validation Parametric rolling Fishing vessel

海洋扰动环境排水型船舶各种载荷条件下的适应性路径跟随控制（英文）

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Journal of Marine Science and Application 2024年第4期 900-913页

作者： Ali Hasanvand mohammad saeed seif Department of Mechanical Engineering Sharif University of Technology

Challenges associated with path-following control for commercial displacement vessels under varying loading and draught conditions are addressed in this study. Adaptive control with the adaptation law technique is used to mitigate the adverse effects of uncertainty and unmodeled parameters on path-following, particularly in the presence of ocean disturbances. The proposed adaptive path-following control estimates the effect of unmodeled parameters and dynamic behavior by the state estimator. Then, the proposed structure adjusts the gains of the L1 controller. The indirect L1 control is used in the main controller, and stability proof is provided based on Lyapunov theory. The adaptive path-following control is proposed for the underactuated-very large crude carrier 2(VLCC2) as a benchmark vessel. Hydrodynamic coefficients for full load and ballast conditions are determined using empirical formulas. Simulations are conducted in these loading conditions, accounting for a two-knot ocean current, two-knot wind, and waves up to sea state 5. Results highlight that the fixed structure, such as the PID controller, fails to deliver satisfactory performance due to significant variations in the vessel's mass, inertia, and draught. By contrast, the adaptive path-following control demonstrates robustness under varying conditions by effectively estimating the vessel's unmodeled parameters.

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A Unified Optimization-Based Framework to Adjust Consensus Convergence Rate and Optimize the Network Topology in Uncertain Multi-Agent Systems

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IEEE/CAA Journal of Automatica Sinica 2021年第9期8卷 1539-1548页

作者： mohammad saeed Sarafraz mohammad Saleh Tavazoei Department of Electrical Engineering Sharif University of TechnologyTehran 11365-9363Iran

This paper deals with the consensus problem in an uncertain multi-agent system whose agents communicate with each other through a weighted undirected(primary)*** considered multi-agent system is described by an uncertain state-space model in which the involved matrices belong to some matrix *** the main contribution of the paper,a unified optimization-based framework is proposed for simultaneously reducing the weights of the edges of the primary communication graph(optimizing the network topology)and synthesizing a controller such that the consensus in the considered uncertain multi-agent system is ensured with an adjustable convergence *** the NP-hardness nature of the optimization problem related to the aforementioned framework,this problem is relaxed such that it can be solved by regular LMI ***/practical-based examples are presented to verify the usefulness of the obtained results.

关键词： Convergence-rate element-wise uncertainty robust controller topology design

Vulnerability of ordinary moment resistant concrete frames

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Earthquake Engineering and Engineering Vibration 2011年第4期10卷 519-533页

作者： mohammad Barkhordary saeed Tariverdilo Department of Civil Eng. Faculty of Eng.Urmia University

The effects of structural modeling （bar slip in lap splice）, ground motion selection process （epsilon effect） and size of a structure （number of bays and stories） on the fragility of reinforced concrete ordinary moment resisting frames are investigated. An analytical model is developed to account for bar slip in lap splice, which exhibits good correlation with existing experimental data. Then, incremental dynamic analysis is used to derive the fragility curves for four model structures. The model structures simulate frames with a different number of bays and stories. Finally, the fragility curves are corrected for the epsilon effect. The results show that slip in the lap splice can significantly increase the failure probability, especially for the collapse prevention limit state. At the same time, it is found that spectral shape has a significant impact on the fragility curves. It is also found that accounting for or ignoring bar slip or epsilon effects increases the probability of failure for larger structures. This indicates an unconservative bias in the safety of larger structures.

关键词： lap-splice slip incremental dynamic analysis fragility curve epsilon effect

RAPID AND FACILE SYNTHESIS OF ACYL AZIDES FROM ACYL HALIDES USING A POLYMER-SUPPORTED AZIDE ION UNDER HETEROGENEOUS CONDITIONS

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Chinese Journal of Polymer Science 2013年第7期31卷 1002-1010页

作者： mohammad Ali Karimi Zarchi saeed Barani Department of Chemistry College of SciencesYazd University

In this article a rapid and facile method for synthesis of acyl azide is described. The cross-linked poly（N-methyl-4- vinylpyridinium） azide ion, [Pa-VP]N3 is prepared and used as an efficient polymeric reagent for synthesis of acyl azides from acyl halides at room temperature under heterogeneous conditions. Various benzoyl halides, with electron-withdrawing groups as well as electron-donating groups, were transformed into the corresponding benzoyl azides in high to excellent yields in short reaction times. The acyl azide products were characterized by FT-IR, and some of them were also characterized by IH- and/or 13C-NMR spectroscopy, and physical properties were compared to literature values of known compounds. The spent polymeric reagents can be regenerated and reused for several times without losing their activity. Relative to the reported methods, the present method has the advantages of operational simplicity, mild reaction conditions, fast reaction rates, simple reaction work-up and lower hazardous and potentially explosive nature. Also the present method is the first procedure for the synthesis of acyl azides from acyl halides by using a polymer-supported azide ion under heterogeneous conditions.

关键词： Acyl azide Acyl halide Polymeric reagent Heterogeneous condition.

Hydrothermal synthesis and physicochemical characterization of CuO/ZnO/Al_2O_3 *** I:Effect of crystallization time

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Particuology 2012年第6期10卷 729-736页

作者： saeed Saedy mohammad Haghighi Mahsa Amirkhosrow Chemical Engineering Department Sahand University of TechnologyP.O.Box 51335-1996Sahand New TownTabrizIran Reactor and Catalysis Research Center Sahand University of TechnologyP.O.Box 51335-1996Sahand New TownTabrizIran

A hydrothermal method was successfully used for synthesis of CuO/ZnO/AI203 （CZA） nanopowder with atomic ratio of 6：3：1. The effect of crystallization time （3, 6, 9, and 12 h） on physicochemical properties of nanopowder was investigated. Nanopowders were characterized using XRD, FESEM, EDX, FTIR, TG, and BET techniques. The XRD patterns confirmed metal oxides formation and their good crystallinity with average crystallite size of 20nm as obtained by the Scherrer equation. Relative crystallinity was shown to increase with increasing crystallization time. In agreement with XRD results, FESEM images also illustrated nanosized particles. EDX mapping indicated homogenous dispersion of elements. BET specific surface area analysis showed acceptable surface area for CZA nanopowder, FTIR spectroscopy confirmed metal oxides formation during hydrothermal and calcination processing. TG results illustrated high thermal stability of the synthesized nanopowders. TG-DTG and FTIR analyses were used to propose a reaction mechanism for nanopowder formation during processing. Physicochemical characterization showed optimal crystallization time to be 6 h.

关键词： ZnO CuO Al2O3 Mixed oxides Nanopowder Hydrorhermal

Particle agglomeration and interphase interactions affect Young’s modulus of nanobiocomposites:eyes at mathematical modeling

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Acta Mechanica Sinica 2024年第9期40卷 10-21页

作者： Pooriya Sarrami mohammad Rafienia saeed Karbasi Student Research Committee School of Advanced Technologies in MedicineIsfahan University of Medical SciencesIsfahan 81746-73461Iran Biosensor Research Center Isfahan University of Medical SciencesIsfahan 81746-73461Iran Department of Biomaterials Nanotechnology and Tissue EngineeringSchool of Advanced Technologies in MedicineIsfahan University of Medical SciencesIsfahan 81746-73461Iran

Computational modeling is a new approach to optimize Young’s modulus of scaffolds by performing a minimal number of ***,presenting a modeling algorithm to predict Young’s modulus and characterize the governing parameters is a challenging ***,a novel modeling approach has been proposed to estimate Young’s modulus of scaffolds,considering particle agglomeration and interphase *** the characteristic parameters of these two phenomena,we modified the Maxwell model using a simple three-step algorithm to determine the optimal value of these parameters and predict Young’s ***,the model provides a precision of more than 95%for all the studied cases and presents a remarkably better performance compared to the two other *** instance,the proposed model has reduced the average absolute relative error of Young’s modulus of poly(3-hydroxybutyrate)-keratin/hydroxyapatite nanorods from 25.1%to 0.08%,demonstrating the high efficiency of this model in predicting Young’s modulus of *** results of this study could lighten the way of fabricating nanobiocomposites with optimal mechanical properties,spending lower cost and energy.

关键词： Predictive models Mechanical properties Polymer nanocomposites Particle agglomeration Bone tissue engineering

Effect of chemical activation process on adsorption of As(V) ion from aqueous solution by mechano-thermally synthesized zinc ferrite nanopowder

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International Journal of Minerals,Metallurgy and Materials 2020年第4期27卷 526-537页

作者： mohammad Sefidmooy Azar Shahram Raygan saeed Sheibani School of Metallurgy and Materials Engineering College of EngineeringUniversity of TehranTehranIran

Nanostructured ZnFe2O4 was synthesized by the heat treatment of a mechanically activated mixture of ZnO/α-Fe2O3.X-ray diffraction(XRD)and differential thermal analysis(DTA)results demonstrated that,after 5 h of the mechanical activation of the mixture,ZnFe2O4 was formed by heat treatment at 750°C for 2 *** improve the characteristics of ZnFe2O4 for adsorption applications,the chemical activation process was *** 2 h chemical activation with 1 mol·L?1 HNO3 and co-precipitation of 52%?57%dissolved ZnFe2O4 led to an increase in the saturated magnetization from 2.0 to 7.5 emu·g?1 and in the specific surface area from 5 to 198 m2·g?*** addition,the observed particle size reduction of chemically activated ZnFe2O4 in field emission scanning electron microscopy(FESEM)micrographs was in agreement with the specific surface area *** improvements in ZnFe2O4 characteristics considerably affected the adsorption performance of this *** results revealed that mechano-thermally synthesized ZnFe2O4 had the maximum arsenic adsorption of 38%with the adsorption capacity of 0.995 mg·g?1 in a 130 mg·L?1 solution of As(V)after 30 min of ***,chemically activated ZnFe2O4 showed the maximum arsenic adsorption of approximately 99%with the adsorption capacity of 21.460 mg·g?1 under the same *** results showed that the weak adsorption performance of mechano-thermally synthesized ZnFe2O4 was improved by the chemical activation process.

关键词： zinc ferrite mechano-thermal chemical activation adsorption arsenic(V)

An optimization model for synchronous road geometric and pavement enhancements

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Journal of Traffic and Transportation Engineering(English Edition) 2021年第3期8卷 421-438页

作者： mohammad Mahanpoor saeed Monajjem Vahid Balali Department of Civil Engineering K.N.Toosi University of TechnologyTehranIran Department of Civil Engineering and Construction Engineering Management California State UniversityLong BeachCA 90840USA

A synchronous optimization model for rehabilitation of existing two-way two-lane(TWTL)highways is proposed in this paper considering geometric modification and existing pavement rehabilitation. The rehabilitation process of existing roadways is categorized into geometric design modifications and pavement repairs. These two types of modification apply separately in roadway life-cycle because of the difference in nature of these repairs, which impose an extra cost and time of closure to road users and owners. This paper aims to address the modification of existing highways by a new approach linking the existing pavement condition and geometric configuration changes of the developed roadway to provide the optimum vertical alignment. The proposed procedure depends on various parameters of existing pavement condition, cross-section configuration, traffic volume and composition, and current alignment composure. In the first step, all these dependencies are explained and quantified with separate cost models. For each solution,the overall cost is calculated with a life-cycle cost analysis approach. Finally, a particle swarm optimization(PSO) based model is developed to find the optimum solution. The developed model was applied in two case studies with good and adverse geometric conditions. The results show that there is a critical condition in the roadway segments which have all these conditions:(1) the grade is more than three percent,(2) the grade is following with reverse grade, and(3) decommissioning of the asphalt concrete(or extended to lower layers) exist. The optimum solution in these critical conditions suggests the modification of the geometric configuration before the pavement rehabilitation in order to reduce the overall cost. In the absence of these conditions, the optimum alignment is more analogous with the existing alignment of the highway.

关键词： Transportation engineering Geometric modification Pavement rehabilitation Optimization Sustainability Safety