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Coupling of RANS and BEM Solvers for Simulation of Propeller Behind the Hull in Full Appended Model

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China Ocean Engineering 2024年第3期38卷 424-438页

作者： Saeed najafi Mehdi POURMOSTAFA LIU Peng-fei Iranian National Institute for Oceanography and Atmospheric Science(INIOAS) Tehran 14155-4781Iran Department of Maritime Engineering Amir Kabir University of TechnologyTehran 15875-4413Iran Marine Offshore and Subsea TechnologySchool of EngineeringNewcastle UniversityNewcastle upon TyneNE17RUUK

To design a propeller for ship power plant,the interaction between ship hull and propeller must be taken into *** main concern is to apply the wake effect of ship stern on the propeller *** this paper,a coupled BEM(Boundary Element Method)/RANS(Renolds-Averaged Navier−Stokes)solver is used to simulate propeller behind the hull in the self-propulsion *** motivation of this work is to develop a practical tool to design marine propulsion system without suffering long computational *** unsteady boundary element method which is also known as panel method is chosen to estimate the propeller *** wakes are treated using a time marching wake alignment ***,a RANS code coupled with VoF equation is developed to consider the ship motions and wake field effects in the problem.A coupling algorithm is developed to interchange ship wake field to the potential flow solver and propeller thrust to the RANS *** on the difference between hull resistance and the propeller thrust,a PI controller is developed to compute the propeller RPM in every time *** of the solver is carried out using the towing tank test report of a 50 m oceanography research *** factor and trust deduction coefficient are estimated ***,the wake rollup pattern of the propeller in open water is compared with the propeller in real wake field.

关键词： RANS BEM coupled method ship propeller self-propulsion wake sheet pattern

Evaluating innovation ecosystem resiliency using agent-based modeling and systems dynamics

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Journal of Safety Science and Resilience 2024年第2期5卷 204-221页

作者： Soheila Abdi Mehdi Yazdani Esmaeil najafi Department of Industrial Engineering Science and Research BranchIslamic Azad UniversityTehranIran Department of Industrial Engineering Qazvin BranchIslamic Azad UniversityQazvinIran

Evaluating the resilience of the innovation ecosystem to maintain its performance,in the sense of resistance to disruption and recovery after it,has recently received more *** studies have been conducted to model different ecosystems and evaluate their ***,modeling the innovation ecosystem from a holistic perspective and performing a quantitative assessment of its resilience have received less *** paper models the innovation ecosystem holistically and evaluates its resilience index using a quantitative approach through five main *** the first step,a case study related to the innovation ecosystem of Iran's Ministry of Energy,called the Power Innovation Ecosystem,is modeled by combining system dynamics and agent-based *** validating the model in the second step,the disruption of the loss of experts is investigated in the third step,and all possible actions to recover each actor are *** the fourth step,the performance of the ecosystem is simulated before and after the disruption using the data gathered in the previous ***,resilience is calculated in two different ways in the fifth *** improvement solutions are also suggested when considering that the resilience index of the innovation ecosystem is at a medium *** research may assist policymakers in observing the resilience level of the innovation ecosystem based on the proposed *** applying strategic changes to this model,they can determine the effects of their policies and make the most appropriate decisions to increase the resilience of the innovation ecosystem.

关键词： Resilience index innovation ecosystem System dynamics Agent-based modeling

Color and Gloss Changes of a Lignin-Based Polyurethane Coating under Accelerated Weathering

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Journal of Renewable Materials 2024年第2期12卷 305-323页

作者： Fatemeh Hassani Khorshidi Saeed Kazemi najafi Farhood najafi Antonio Pizzi Dick Sandberg Rabi Behrooz Department of Wood Science and Technology Faculty of Natural ResourcesTarbiat Modares UniversityTehranIran Department of Resin and Additives Institute for Color Science and TechnologyP.O.Box 16765-654TehranIran LERMAB University of LorraineBlvd des AiguillettesNancy54000France Wood Science and Engineering LuleåUniversity of TechnologySkellefteåSweden

The purpose of this research study was to investigate the properties of polyurethane coatings based on lignin *** this purpose,the prepared coatings were applied to pine wood surfaces and weathered ***,color and gloss of the coatings were measured before and after the weathering *** emission scanning electron microscopy(FE-SEM)micrographs prepared from the coatings showed that the average size of nano-particles in the polyurethane substrate was approximately 500 *** magnetic resonance(13C-NMR)spectroscopy showed that strong urethane bonds were formed in the nano-lignin-based *** calorimetric analysis(DSC)test revealed that the glass-transition temperature(Tg)of lignin nanoparticles modified with diethylenetriamine(DETA)was 112.8℃ and Tg of lignin nano-particles modified with ethylenediamine(EDA)was 102.5℃,which is lower than the Tg of un-modified lignin(114.6℃)and lignin modified with DETA(126.8℃)and lignin modified with EDA(131.3℃).The coatings modified with lignin nano-particles had a greater change in *** lignin nano-particles in the modified coating are trapping hydroxyl radicals which reduces photoactivity and yellowing of the polyurethane by about 3 times compared to unmodified polyurethane *** weathering test,the nano-lignin-based coating had a rougher surface with a lower contact angle(0.78°)compared to the unmodified polyurethane coating(0.85°).

关键词： Amination propylene carbonate lignin biopolymer polyurethane coating polyol UN SDG 13

A thermo-mechanical simulation for the stability analysis of a horizontal wellbore in underground coal gasification

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Petroleum 2024年第2期10卷 243-253页

作者： Mohammadreza Shahbazi Mehdi najafi Mohammad Fatehi Marji Ramin Rafiee Department of Mining and Metallurgical Eng. Yazd UniversityYazdIran Department of Mining Petroleum&Geophysics Eng.Shahrood University of TechnologyShahroodIran

The stability analysis of horizontal wells is essential for a successful underground coal gasification(UCG)*** this paper,a new 3D coupled thermo-mechanical numerical modeling is proposed for analyzing the stability of UCG horizontal *** this model,the effect of front abutment stresses,syngas pressure,syngas temperature and thermal stresses is considered to predict the mud weight window and drilling mud pressure during UCG *** results show that the roof caving in UCG panel has a greatest impact on the stability of horizontal ***,when the time of coal gasification is increased,the well convergence increases and for more stability it is necessary to increase the drilling mud *** research was carried out on the M2 coal seam in Mazino coal deposit(Iran).The results showed that the mud weight window for horizontal well drilling is between 0 and 33 *** appropriate stress for the maximum stability of the horizontal well,taking all the thermal and mechanical parameters into account,is 28 *** suggested numerical method is a comprehensive and consistent way for analyzing the stability of horizontal wells in UCG sites.

关键词： Underground coal gasification Thermo-mechanical simulation Numerical modeling Stress distribution Horizontal well

Dehydration of fructose and glucose to 5-hydroxymethylfurfural over Al-KCC-1 silica

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Journal of Energy Chemistry 2018年第3期27卷 769-780页

作者： Fereshte Shahangi alireza najafi chermahini Mohammad Saraji Department of Chemistry Isfalzan University of Technology84154-83111Isfahan.Iran

In this research, the influence of several factors such as reaction time, catalyst weight, temperature and different solvents on dehydration reaction of fructose and glucose to 5-hydroxymethylfurfural（HMF） was surveyed. Nanosphere Al-KCC-1 silica with fibrous morphology was manufactured and used as proficient and recyclable catalyst for this reaction. SEM, TEM, BET, XRD, EDX, elemental mapping, ICP and FT-IR spectroscopy methods were applied for characterization of the Al-KCC-1（molar ratio Si/Al = 5, 40） catalysts. 162℃ and 1 h are the best conditions for the fructose dehydration. Under this situation HMF yield and selectivity are 92.9% and 94.5% respectively and fructose conversion is 98.4%. Also 170℃ and 2 h are the best conditions for the glucose dehydration. In this situation HMF yield and selectivity are 39.0% and39.9% respectively and glucose conversion is 97.8%.

关键词： Glucose Fructose HMF production Al-KCC-1 Dehydration of carbohydrates

Examining the Effect of Hydroalcoholic Extract of Dracaena cinnabari on Sex Hormones and Ovarian and Uterine Tissues of Rats

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World Journal of Traditional Chinese Medicine 2024年第2期10卷 213-219页

作者： Elham najafi Bahareh Babaei Hoolari Akbar Karimi Aliasghar Pilehvarian Department of Cellular Biology Genesis Evolution-Develoment Isfahan Payame Noor University IsfahanIran Department of Anatomy School of MedicineTehran University of Medical SciencesTehranIran Department of Biology Group Faculty Member of Isfahan Payame Noor UniversityIsfahanIran

Introduction: Dracaena cinnabari is considered a rich source of phytochemicals used widely in traditional medicine. In the present study, the effect of D. cinnabari hydraulic extract on the reproductive system of female rats was investigated. Methods: The samples were randomly divided into four groups(six samples in each group), including three treatment groups and one control group, and all samples were kept at the same conditions. Hydraulic extract of D. cinnabari and injected intraperitoneally daily for 10 days, while physiological serum was used for injection in to the control group. After 10 days of injection, estrogen and progesterone levels were measured by enzyme immunoassay technique. After dissection, the ovaries and uterine tissues were isolated for histological examination, and tissue changes were carefully examined. Results: The results revealed that the levels of estrogen and progesterone in experimental Groups 2 and 3 had a significant increase(P < 0.001). Regarding tissue changes, a significant increase was observed in epithelial thickness(P < 0.001), number of corpus luteum(P < 0.01), and Graafian follicle(P < 0.01) in doses of 100 and 150 mg/kg. Conclusions: Based on the results, it seems that D. cinnabari extract has an effect on the ovarian follicles.

关键词： Dracaena cinnabari herbal medicine ovarian tissues reproductive sex hormones

Direct production of hydrogen peroxide over bimetallic CoPd catalysts:Investigation of the effect of Co addition and calcination temperature

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Green Energy & Environment 2023年第1期8卷 246-257页

作者： Hamidreza Nazeri alireza najafi chermahini Zahra Mohammadbagheri Mirko Prato Department of Chemistry Isfahan University of Technology84154-83111IsfahanIran Materials Characterization Facility Istituto Italiano di TecnologiaVia Morego 3016163GenovaItaly

A series of CoPd/KIT-6 bimetallic catalysts with various Co:Pd molar ratios at different calcination temperatures were prepared and used for the direct synthesis of H_(2)O_(2) from H_(2) and O_(2).These catalysts were characterized by nitrogen adsorption-desorption,low and wide-angle X-ray diffraction(XRD),X-ray photoelectron spectroscopy(XPS),transmission electron microscopy(TEM),scanning electron microscopy(SEM),elemental mapping and energy-dispersive X-ray(EDX)*** was found that the particle size,electronic interactions,morphology,and textural properties of these catalysts as well as their catalytic activity in the reaction of H_(2) with O_(2) were affected by Co addition and different calcination ***,the results showed that while the H_(2)O_(2) selectivity depends on Pd^(2+) species,the H_(2) conversion is related to Pd0 active *** these catalysts,CoPd/KIT-6 calcined at 350℃(CoPd/KIT-350 catalyst)showed the best catalytic activity with 50%of H_(2)O_(2) selectivity and 51%conversion of H_(2).

关键词： Direct synthesis of hydrogen peroxide Co/Pd catalysts Selectivity The oxidation state of Pd Reusability

Synthesis of mono and bis-4-methylpiperidiniummethyl-urea as corrosion inhibitors for steel in acidic media

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Frontiers of Chemical Science and Engineering 2011年第1期5卷 43-50页

作者： Abbas TEIMOURI Nasrin SOLTANI alireza najafi chermahini Department of Chemistry Payame Noor University(PNU)Isfahan 81395-671Iran Department of Chemistry Payame Noor University(PNU)Shahin Shahr BranchIsfahan 83196Iran Department of Chemistry Yasouj UniversityYasouj 75918-74831Iran

Mono and bis-4-methylpiperidiniummethyl urea were synthesized,characterized and used as new corrosion inhibitors of mild steel in the acidic *** effect of two compounds on mild steel surface in the 1 mol·L^(–1 )sulphuric acid has been studied by a series of techniques,such as potentiodynamic polarization,weight loss and quantum chemical calculation *** polarization measurements showed that two inhibitors are mixed *** measurements showed that inhibition efficiencies enhanced with increase of inhibitor *** reveals that inhibitive actions of inhibitors were mainly due to adsorption on mild steel *** functional(DFT)calculations have been carried out for the title compounds by performing HF and DFT levels of theory using the standard 6-31G*basis set.

关键词： corrosion inhibitors mild steel acidic medium theoretical studies DFT

Isoimperatorin alleviates acetic acid-induced colitis in rats

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Asian Pacific Journal of Tropical Biomedicine 2024年第4期14卷 147-153页

作者： Saied Goodarzi Amir Hossein Abdolghaffari Behnaz najafi Mostafa Pirali Hamedani Saeed Tavakoli Mahshad Marvi Maryam Baeeri Narguess Yassa Abbas Hadjiakhoondi Mohammad Abdollahi Zahra Tofighi Medicinal Plants Research Center Faculty of PharmacyTehran University of Medical SciencesTehranIran Department of Toxicology and Pharmacology Faculty of PharmacyTehran Medical SciencesIslamic Azad UniversityTehranIran Department of Pharmacognosy Faculty of PharmacyTehran University of Medical SciencesTehranIran Medicinal Plants Research Center Institute of Medicinal PlantsACECRKarajIran International Campus School of Pharmacy Tehran University of Medical SciencesTehranIran Toxicology and Diseases group The Pharmaceutical Sciences Research CenterTehran University of Medical SciencesTehranIran Department of Toxicology and Pharmacology Faculty of PharmacyTehran University of Medical SciencesTehranIran

Objective:To investigate the effect of isoimperatorin on histopathological and biochemical changes in acetic acid-induced colitis ***:Colitis was induced by intracolonic administration of acetic acid solution(4%v/v)in *** were divided into six groups including the sham group,the negative control group,the dexamethasone-treated group,and the groups treated with isoimperatorin(0.1,1,and 10 mg/kg/d by gavage).The treatments were administered for three days and then colonic status was assessed by macroscopic,histopathological,and biochemical ***:Isoimperatorin significantly alleviated colonic damage in a dose-dependent manner and improved histological changes in rats with acetic acid-induced *** also significantly reduced myeloperoxidase,TNF-α,IL-1β,and malodialdehyde ***:Isoimperatorin alleviates acetic acid-induced colitis in rats and may be a potential therapeutic agent for the treatment of colitis.

关键词： Isoimperatorin Inflammatory bowel disease Acetic acid Colitis TNF-α IL-1β