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Performance improvement of a crumb rubber modified bitumen using recycled glass powder

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第11期14卷 805-814页

作者： Mojtaba GHASEMI seyed Morteza MARANDI Department of Civil Engineering Shahid Bahonar UniversityKerman 761691 4111 Iran

In this study, the efficiency of bitumen and asphalt mixtures modified with crumb rubber(CR) and recycled glass powder(RGP) is evaluated. From an environmental point of view, the application of RGP in asphalt mixtures is considered beneficial since it prevents accumulation of waste glass in the natural environment. Rheological and mechanical properties of modified bitumen samples were investigated by laboratory methods such as bitumen conventional tests and dynamic shear rheometer(DSR), and also by asphalt mixture performance tests including Marshall stability, indirect tensile strength(ITS),compressive strength, and indirect tensile stiffness modulus. The results showed that the application of RGP in place of CR has no negative impact on the efficiency of bitumen and asphalt mixtures and even improves their engineering properties except for the toughness index(TI). Moreover, a modification with 5% CR and 5% RGP in asphalt mixtures results in the best overall performance.

关键词： Crumb rubber (CR) Recycled glass powder (PGP) Rheological properties Performance testing Stone matrixasohalt (SMA)

Experimental and numerical analysis of beam to column joints in steel structures

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Frontiers of Structural and Civil Engineering 2018年第4期12卷 642-661页

作者： Gholamreza ABDOLLAHZADEH seyed Mostafa SHABANIAN Faculty of Civil Engineering Babol Noshirvani University of TechnologyBabolIran

The behaviors such as extreme non-elastic response, constant changes in roughness and resistance, as well as formability under extreme loads such as earthquakes are the primary challenges in the modeling of beam-to-column connections. In this research, two modeling methods including mechanical and neural network methods have been presented in order to model the complex hysteresis behavior of beam-to-column connections with flange plate. First, the component-based mechanical model will be introduced in which every source of transformation has been shown only with geometrical and material properties. This is followed by the investigation of a neural network method for direct extraction of information out of experimental data. For the validation of behavioral curves as well as training of the neural network, the experiments were carried out on samples with real dimensions of beam-to-column connections with flange plate in the laboratory. At the end, the combinational modeling framework is presented. The comparisons reveal that the combinational modeling is able to display the complex narrowed hysteresis behavior of the beam-to-column connections with flange plate. This model has also been successfully employed for the prediction of the behavior of a newly designed connection.

关键词： beam to column connections experiments component method neural network model combinational modeling

Numerical and Performance Analysis of one row Transonic Rotor with Sweep and Lean angle

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Journal of Thermal Science 2014年第5期23卷 438-445页

作者： seyed Reza Razavi Masoud Boroom Aerospace Engineering Department AmirKabir University of Technology

In this study,aerodynamic behaviors of swept and leaned blades were *** and tangential blade curvatures impacts on compressor's operating parameters were analyzed separately.A commercial CFD program which solves the Reynolds-averaged Navier-Stokes equations was used to find out the mentioned impact and the complicated flow field of transonic *** CFD method that was used for solving flow field's equation was validated by experimental data of NASA Rotor *** results showed that the compressor with curved rotors had higher efficiency,rotor pressure ratio and stable operating range compared to the compressor with un-curved *** curved rotors mostly had higher impact on the overall stable operating range compared to the other operating *** range involves choking point and stall point that were changed separately by using of bended *** finding the detailed impact of sweep and lean angle on transonic blades,various forms of lean and sweep angles were exerted to basic *** was found that sweep angles increased overall operating range up to 30%,efficiency up to 2%and pressure ratio up to 1%.Leaning the blades increased the safe operating range,the pressure ratio and efficiency by 14%,4%and 2%respectively.

关键词： compressor performance efficiency stable operational range surge improvement swept Rotor leaned rotor

Effect of ultrasonic irradiation on rheological properties of asphaltenic crude oils

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Petroleum Science 2012年第1期9卷 82-88页

作者： MOUSAVI seyed Mohammadreza RAMAZANI Ahmad NAJAFI Iman DAVACHI seyed Mohammad Ultrasonic Research Group Chemical and Petroleum Engineering Department Sharif University of TechnologyAzadi Ave. Tehran Iran Chemical and Petroleum Engineering Department Sharif University of TechnologyAzadi Ave. Tehran Iran Ultrasonic Research Group Chemical and Petroleum Engineering Department Sharif University of Technology Azadi Ave. Tehran Iran Chemical and Petroleum Engineering Department Sharif University of Technology Azadi Ave. Tehran Iran

In this work, the rheological changes of several crude oil samples exposed to ultrasonic waves for different time intervals in addition to the effect of temperature on viscosity behavior of heavy crude oils were investigated using a series of steady shear flow and oscillatory tests. The colloidal structural evolutions of flocs in oil samples were illustrated by analysis of the size distribution of flocculated asphaltene particles （confocal microscopy tests）. The rheological investigations indicate that the ultrasonic irradiation dissolved heavy components in crude oil. After ultrasonic treatment, the Kouh-e-Mond crude oil was found to be pseudoplastic. In addition, confocal microscopy confirms that there was an optimum duration for ultrasonic irradiation, at which the viscosity and flocculation rate of asphaltenic crude oils reduced to the minimum values. The optimum was found to be approximately 40 min for the Kouh-e-Mond crude oil. Experimental results illustrate that the ultrasonic irradiation could disaggregate heavy colloid components in crude oil, and breakdown of asphaltene molecules would only occur in a specific time interval of irradiation. Also according to the temperature sweep test, the oil temperature rise caused by ultrasonic irradiation was not the main reason for theological changes of the crude oil and this alteration may be due to physical and chemical phenomena induced by sonication in crude oil.

关键词： Asphaltene ultrasonic technology pseudoplastic property viscoelastic property yield stress,flocculation time

Enhanced microstructural and mechanical properties of Stellite/WC nanocomposite on Inconel 718 deposited through vibration-assisted laser cladding

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International Journal of Minerals,Metallurgy and Materials 2022年第2期29卷 327-334页

作者： Hossein Hosseini-Tayeb seyed Mahdi Rafiaei Daneshpajoohan Pishro Higher Education Institute IsfahanIran Department of Materials Science and Engineering Golpayegan University of TechnologyGolpayeganIsfahanIran

Stellite-21/WC nanopowders were deposited on Inconel through vibration-assisted laser cladding with different laser *** and scanning electron microscopy,hardness measurements,and wear characterizations were employed to understand the microstructural and mechanical behaviors of the *** showed that varying the cooling rate exerted remarkable effects on the microstructure of the as-cladded ***,increasing the laser power from 150 W to 250 W increased the heat input and the *** was affected by the scanning rate and powder feeding rate at a high laser power of 250 *** WC nanoparticles were added as reinforcement,the dilution magnitude intensified while the hardness value increased from HV 350 to HV *** wear characterizations indicated that the composites containing 3 wt%WC nanoparticles possessed the highest wear resistance.

关键词： Stellite WC nanoparticles mechanical properties laser cladding

Estimating Network Connectedness of Financial Markets and Commodities

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Journal of Systems Science and Systems Engineering 2020年第5期29卷 572-589页

作者： Ehsan Bagheri seyed Babak Ebrahimi Financial Engineering Group Faculty of Industrial EngineeringK.N.Toosi University of TechnologyTehranIran

We investigate the directional volatility and return network connectedness among stock,commodity,bond,currency and cryptocurrency *** period of study covers Feb 2006 until August *** utilize and expand Diebold and Yilmaz(20142015)connectedness measurement;accordingly,in the variance decomposition structure,we use Hierarchical Vector Autoregression(HVAR)to estimate high dimensional networks more *** empirical results show that markets are highly connected,especially during *** stock markets are the net receiver of shocks,while European and American stock markets are the net transmitter of shocks to other *** pairwise connectedness results suggest that among stock markets,DAX-CAC 40,FTSE 100-CAC 40 and S&P 500-S&P_TSX index are more integrated through connectedness than the *** other markets,WTI crude oil-Brent crude oil,30-Year bond and 10-Year bond,Dollar Index futures-EUR/USD have notable *** terms of cryptocurrencies,they contribute insignificantly to other markets and are highly integrated with each *** and cryptocurrencies seem to be good choices for investors to hedge during a crisis.

关键词： Financial markets network connectedness econometrics commodity

Nonlinear finite time attitude control of flexible spacecraft based on a novel output redefinition method

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Chinese Journal of Aeronautics 2023年第11期36卷 373-385页

作者： seyed Majid ESMAEILZADEH Mohammad Sadegh ZEYGHAMI Department of Electrical Engineering Iran University of Science and TechnologyNarmakTehran 16846-13114Iran

A finite time attitude controller is designed for a flexible spacecraft based on a novel output redefinition method, in this paper. To make the flexible appendages vibration suppression effective, the appendage tip-point is selected as the output. First, a novel output redefinition method is proposed to overcome the non-minimum phase property of the dynamic model. The proposed method not only makes the system model minimum phase but also improves the attitude control system performance. Consequently, the precise attitude pointing and stabilization are ***, a nonlinear finite time H∞controller is designed based on the backstepping approach. For the situation where the modal variables measurements are not available, a modal observer is also designed. The simulation results show the effectiveness of the proposed method in the presence of the model uncertainties and environmental disturbances.

关键词： Finite time Output redefinition H1 control Attitude control Flexible spacecraft Backstepping Robust

Propylsulfonic acid functionalized nanozeolite clinoptilolite as heterogeneous catalyst for the synthesis of quinoxaline derivatives

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Chinese Chemical Letters 2015年第9期26卷 1113-1116页

作者： seyed Meysam Baghbanian Department of Chemistry Ayatollah Amoli BranchIslamic Azad University

In this work,the natural nanozeolite clinoptilolite（Nano CP） was successfully functionalized by propylsulfonic acid and applied as efficient heterogeneous catalyst for the synthesis of quinoxaline derivatives in aqueous *** nanocatalyst was characterized by various techniques such as CHN,XRD,FT-IR,BET,TGA/DTA,SEM,TEM and *** results show its applicability as green,reusable and promising catalyst in organic *** was found that the nanocatalysts could be recycled and reused eight times without significant loss of catalytic activities.

关键词： Clinoptilolite Heterogeneous catalyst Nanozeolite Propylsulfonic acid O_uinoxalines

LaZn_xFe_(1-x)O_3钙钛矿型纳米催化剂的制备、表征及其甲苯燃烧性能(英文)

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催化学报 2010年第7期31卷 747-750页

作者： seyed Ali HOSSEINI Mohammad Taghi SADEGHI Abdolali ALEMI Aligholi NIAEI Dariush SALARI Leila KAFI-ahmadi Department of Applied Chemistry Faculty of ChemistryUniversity of Tabriz Department of Inorganic Chemistry Faculty of ChemistryUniversity of Tabriz

Nanostructured LaFeO3 and substituted LaZnxFe1-xO3(x = 0.01,0.05,0.1,0.2,and 0.3) perovskites were synthesized by the sol-gel auto-combustion method and used in the catalytic combustion of *** structures and surface properties were investigated by X-ray diffraction,Fourier transmission infrared spectroscopy,BET surface area,and scanning electron *** data revealed that the total insertion of zinc into LaFeO3 takes place when x ≤ ***,ZnO segregation occurs to some extent,especially at x > *** performance of these perovskites was evaluated by toluene *** catalytic activity of the catalysts increased substantially with an increase in zinc *** results can be attributed to the cooperative effect between LaZnxFe1-xO3 and the zinc oxide *** relative concentration of these phases determines their oxygen activation ability and reactivity.

关键词： sol-gel auto-combustion perovskite toluene catalytic oxidation LaZnxFe1-xO3