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Transesterification of canola oil over Li/Ca-La mixed oxide catalyst:Kinetics and calcination temperature investigations

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燃料化学学报 2017年第4期45卷 442-448页

作者： hesam Maleki Mohammad Kazemeini Department of Chemical and Petroleum Engineering Sharif University of Technology

In this research,a solid 1%Li/Ca-La mixed oxide catalyst was prepared using co-precipitation method followed by wet *** prepared catalyst was used in the transesterification reaction of canola oil and methanol for biodiesel *** effects of calcination and reaction temperatures were investigated on the activity of the *** addition,rate of the reaction was studied through a kinetic model for which parameters were *** properties and structure of the catalyst were characterized through the powder X-ray diffraction(XRD),thermogravimetry/derivative thermogravimetry(TG/DTG),and Fourier transform infrared spectroscopy *** these emphasized that the performance of the catalyst corresponded to the generation of the active sites and their thermal activation.

关键词：油共炼基团相对含量固体残渣干基无灰转化率

Investigating a potential reservoir landslide and suggesting its treatment using limit-equilibrium and numerical methods

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Journal of Mountain Science 2017年第3期14卷 432-441页

作者： Nima BABANOURI hesam DEHGHANI Department of Mining Engineering Hamedan University of Technology***HamedanIran

A reservoir landslide not only reduces the water storage capacity, but also causes extensive damages to the dam body, power/water transmission lines, roads, and other infrastructures. The Latian Dam, located 35 km north east of Tehran （Iran）, is one of the cases which has encountered serious problems with instability of its rock abutments. This paper addresses the stability analysis of the right abutment of the Latian Dam using limit equilibrium and numerical methods. Geomechanical characteristics of the rock abutment were first estimated based on engineering classification of the rock mass. Different search methods were examined for locating the critical circular/non-circular slip surface in conjunction with the general limit equilibrium method. The effect of variabi]ity of rock mass properties, water table, and earthquake load on the factor of safety （FS） and probability of failure （PF） was studied. In the event of rapid drawdown in the reservoir, the limit equilibrium analysis calculated FS=1.067 and PF=21.1%, and the numerical analysis returned FS=1.01. The results of the analyses suggest that the right abutment of the Latian Dam is prone to slide and needs treatment. Investigations demonstrated that a slope reduction by 15° at the upper part of the abutment would meet stability conditions even in the worst-case scenario （FS=1.297 and PF=2.07%）.

关键词： Reservoir landslide Limit equilibrium Numerical modeling Reliability Slope stabilization

Maximum entropy based finite element analysis of porous media

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Frontiers of Structural and Civil Engineering 2019年第2期13卷 364-379页

作者： Emad NOROUZI hesam MOSLEMZADEH Soheil MOHAMMADI High Performance Computing Laboratory School of Civil EngineeringFaculty of EngineeringUniversity of TehranTehranIran

The maximum entropy theory has been used in a wide variety of physical, mathematical and engineering applications in the past few years. However, its application in numerical methods, especially in developing new shape functions, has attracted much interest in recent years. These shape functions possess the potential for performing better than the conventional basis functions in problems with randomly generated coarse meshes. In this paper, the maximum entropy theory is adopted to spatially discretize the defonnation variable of the governing coupled equations of porous media. This is in line with the well-known fact that higher-order shape functions can provide more stable solutions in porous problems. Some of the benchmark problems in deformable porous media are solved with the developed approach and the results are compared with available references.

关键词： maximum entropy FEM fully coupled multi-phase system porous media

Secure ticket-based authentication method for IoT applications

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Digital Communications and Networks 2023年第3期9卷 710-716页

作者： Mojtaba Alizadeh Mohammad hesam Tadayon Alireza Jolfaei Computer Engineering Department Lorestan UniversityKhorramabadIran Iran Telecommunication Research Center(ITRC) TehranIran Department of Computing Macquarie UniversitySydneyAustralia

The recent surge in the number of machines,appliances,and services connected to the Internet demands secure processing and transmission of sensory *** plays a crucial role in a typical security model used in the Internet of Things(IoT),and it protects data communications from various attacks,such as impersonation and denial of service,by verifying and allowing legitimate users to access the IoT ***,recent authentication literature has not addressed the need for developing a scalable and efficient authentication method in this *** paper proposes a secure and anonymous ticket-based authentication method for the *** proposed method protects the network from various security and privacy threats such as data alternation and denial of service while also offering mutual authentication and sensor *** security and performance evaluations confirm the improvement.

关键词： IoT Internet of things Authentication Privacy Security

Synthesis and stability evaluation of hierarchical silicoaluminophosphates with different structural frameworks in the methanol to olefins process

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Particuology 2018年第2期16卷 43-53页

作者： Seyed hesam Mousavi Shohreh Fatemi Marian Razavian School of Chemical Engineering College of Engineering University of Tehran P.O. Box 11365 4563 TehranIran

Silicoaluminophosphates （SAPOs） with different pore structures were synthesized through the implementation of polyethylene glycol （PEG） as a mesopores impregnation agent. Using PEGs with different molecular weights （MWs） and concentrations in the synthesis precursor, several samples were synthesized and characterized. Applying a PEG capping agent to the precursors led to the formation of tuned mesopores within the microporous matrix of the SAPO. The effects of the PEG molecular weight and PEG/Al molar ratio were investigated to maximize the efficiency of the catalyst in the methanol-to-olefin （MTO） process. Using PEG with a MW of 6000 resulted in the formation of both Zeolite Rho and chabazite structural frameworks （i.e., DNL-6 and SAPO-34）. Pure SAPO-34 samples were successfully prepared using PEG with a MW of 4000. Our results showed that the PEG concentrations affect the porosity and acidity of the synthesized materials. Furthermore, the SAPO-34 sample synthesized with PEG （MW of 4000） and a PEG/Al molar ratio of 0.0125 showed a superior catalytic stability in the MTO reaction owing to the tuned bi-modal porosity and tailored acidity pattern. Finally, through reactivation experiments, it was found that the catalyst is stable even after several regeneration cycles.

关键词： Hierarchical SAPO-34 PEG Mesoporosity DNL-6 zeolite MTO process Catalytic stability

Performance of a novel bent-up bars system not interacting with concrete

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Frontiers of Structural and Civil Engineering 2019年第6期13卷 1301-1315页

作者： Aydin SHISHEGARAN Mohammad Reza GHASEMI hesam VARAEE School of Civil Engineering Iran University of Science and TechnologyTehran 13114-16846Iran Structural Engineering Department of Civil EngineeringUniversity of Sistan and BaluchestanZahedan 98167-45845Iran Structural Engineering Ale Taha Institute of Higher EducationTehran 14888-36164Iran

Increasing the bending and shear capacities of reinforced concrete members is an interesting issue in structural *** recent years,many studies have been carried out to improve capacities of reinforced concrete members such as using post and pre-tensioning,Fiber Reinforced Polymer and other *** paper proposes a novel and significant technique to increase the flexural capacity of simply supported reinforced concrete *** proposed method uses a new reinforcement bar system having bent-up bars,covered with rubber *** technique will avoid interaction of bent-up bars with *** are located in the zone where compressive and tensile forces act against one anothe匚The compressive force in the upper point of the bent-up bars is exerted to the end point of these bars located under neutral ***,the tensile stress is decreased in reinforcements located under the neutral *** will cause the Reinforced Concrete(RC)beam to endure extra loading before reaching yield *** factors may well be considered as reasons to increase bending capacity in the new *** laboratory work together with finite element method analysis were carried out in this ***,bending capacity,ductility,strength,and cracking zone were assessed for the new proposed system and compared with the conventional *** the FEM simulation and the experimental test results revealed that the proposed system has significant impact in increasing the load bearing capacity and the stiffness of the RC *** the present study,an equation is formulated to calculate bending capacity of a new reinforcement bar system beam.

关键词： bending capacity rubber tube stress transfer bent-up bars ductility cracking

Emerging role of colorectal mucus in gastroenterology diagnostics

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World Journal of Gastroenterology 2022年第12期28卷 1220-1225页

作者： hesam Ahmadi Nooredinvand Andrew Poullis Department of Gastroenterology St George's HospitalLondon SW170QTUnited Kingdom

Colonoscopy is currently the gold standard for diagnosis of inflammatory bowel disease(IBD)and colorectal cancer(CRC).This has the obvious drawback of being invasive as well as carrying a small *** most widely used non-invasive approaches include the use of faecal calprotectin in the case of IBD and fecal immunochemical test in the case of ***,the necessity of stool collection limits their acceptability for some *** the recent years,there has been emerging data looking at the role of non-invasively obtained colorectal mucus as a screening and diagnostic tool in IBD and *** has been shown that the mucus rich material obtained by self-sampling of anal surface following defecation,can be used to measure various biomarkers that can aid in diagnosis of these conditions.

关键词： Colorectal mucus Inflammatory bowel disease Crohn's disease Ulcerative colitis Colorectal cancer Faecal calprotectin

Design and optimization of equivalent consumption minimization strategy for 4WD hybrid electric vehicles incorporating vehicle connectivity

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Science China(Technological Sciences) 2018年第1期61卷 147-157页

作者： QIU LiHong QIAN LiJun ZOMORODI hesam PISU Pierluigi Department of Vehicle Engineering Hefei University of Technology International Center for Automotive Research Clemson University

This paper presents an optimized equivalent consumption minimization strategy(ECMS) for four-wheel-drive(4 WD) hybrid electric vehicles(HEVs) incorporating vehicle connectivity. In order to be applicable to the 4 WD architecture, the ECMS is designed based on a rule-based strategy and used under the condition that a certain propulsion mode is activated. Assuming that a group of 4 WD HEVs are connected and position information can be shared with each other, we formulate a decentralized model predictive control(MPC) framework that compromises fuel efficiency, mobility, and inter-vehicle distance to optimize the velocity profile of each individual vehicle. Based on the optimized velocity profile, an optimization problem considering both fuel economy and battery state of charge(SOC) sustainability is formulated to optimize the equivalent factors(EFs) of the ECMS for HEVs over an appropriate time window. MATLAB User Datagram Protocol(UDP) is used in the codes run on multiple computers to simulate the wireless communication among vehicles, which share position information via UDP-based communication, and dSPACE is used as a software-in-the-loop platform for the simulation of the optimized ECMS. Simulation results validate the control effectiveness of the proposed method.

关键词： equivalent consumption minimization strategy(ECMS) hybrid electric vehicles(HEVs) model predictive control(MPC) connected vehicles signal phase and timing(SPAT) optimization

NUMERICAL SIMULATION OF FLOW OVER TWO CIRCULAR CYLINDERS IN TANDEM ARRANGEMENT

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Journal of Hydrodynamics 2011年第1期23卷 114-126页

作者： DEHKORDI Behzad Ghadiri MOGHADDAM hesam Sarvghad JAFARI Hamed Houri Department of Mechanical Engineering School of EngineeringTarbiat Modares University

In this article,the 2-D unsteady viscous flow around two circular cylinders in a tandem arrangement is numerically simulated in order to study the characteristics of the flow in both laminar and turbulent *** method applied alternatively is based on the finite volume method on a Cartesian-staggered *** great source term technique is employed to identify the cylinders placed in the flow *** apply the boundary conditions,the ghost-cell technique is *** implemented computational method is firstly validated through simulation of laminar and turbulent flows around a fixed circular ***,the flow around two circular cylinders in a tandem arrangement is simulated and *** flow visualization parameters,the Strouhal numbers,and drag and lift coefficients are comprehensively presented and compared for different cases in order to reveal the effect of the Reynolds number and gap spacing on the behavior of the *** obtained results have shown two completely distinct flow characteristics in laminar and turbulent regimes.

关键词： circular cylinders tandem arrangement vortex shedding hydrodynamic forces