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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

Evaluation of heavy metal contamination hazards in nuisance dust particles, in Kurdistan Province, western Iran

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Journal of Environmental Sciences 2013年第7期25卷 1346-1354页

作者： reza Bashiri Khuzestani Bubak Souri Department of Environmental Sciences Faculty of Natural Resources University of Kurdistan

The effects of natural andgeochemical factors depending on heavy metal contamination in nuisance dust particles were evaluated. The nuisance dust particles were sampled using passive deposit gauge method for one year from April2010 to March2011 and the obtained samples were measured for the total contents and the contamination levels of Fe, Mn, Cu and As usinggeo-accumulation index （Igeo ）, enrichment factor （EF） and the integrated pollution index （IPI）. The results showed that, the contamination levels of Fe and Mn based on Igeo values, were uncontaminated （Igeo 〈 0）（variations of the Igeo index was from -3.11 to -1.751 for Fe, from -0.630 to -1.925 for Mn）, while the values of Cu and As were demonstrated to have moderate contamination based on Igeo values （variations of Igeo index was from -1.125 to 0.848 for Cu, and from -2.002 to 1.249 for As）. The analysis of EF also revealed minor to moderate enrichment for Mn （1.215-4.214）, minor to moderately severe enrichment for Cu （2.791-6.484）, and As （1.370-8.462）, respectively. The variation of the IPI index also showed low to moderate level of heavy metal pollution in nuisance dust particulates （0.511-1.829）. The analysis of the results also approved that the natural processes andgeochemical variables （the changing meteorological parameters） can significantly affect the availability of heavy metals in nuisance dust particles in Western Iran.

关键词： heavy metal contamination nuisance dust deposit gauge method geo-accumulation index enrichment factor integrated pollution index

The investigation and optimization of drag reduction in turbulent flow of Newtonian fluid passing through horizontal pipelines using functionalized magnetic nanophotocatalysts and lecithin

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Chinese Journal of Chemical Engineering 2020年第1期28卷 63-75页

作者： Nadia Esfandiari reza zareinezhad Zahra Habibi Department of Chemical Engineering Marvdasht BranchIslamic Azad UniversityMarvdashtIran

The nanophotocatalysts were synthesized in four stages and evaluated by FTIR, FESEM and VSM analysis. The influence of nanofluids containing functionalized magnetic Ti O2 nanophotocatalyst and dipalmitoylphosphatidylcholine lecithin in drag reduction of turbulent flow in four horizontal pipelines was studied. The effective parameters on drag reduction(nanoparticle concentration, surfactant concentration, p H and Re number) were investigated and optimized in each pipeline using response surface method. The drag reduction in 1/2 " galvanized, 3/4" galvanized, 1/2 "five-layer and 1/2" cuprous pipelines was found 99.1%, 92.5%, 87.6% and 85.2%, respectively. The model adequacy was measured using ANOVA. Based on the high determination coefficient, more than 95% of variance of experimental data in all pipelines was described by quadratic model.

关键词： Drag reduction Lecithin Functionalized magnetic nanophotocatalyst Turbulent flow Response surface

Preparation of La-Mo-V mixed-oxide systems and their application in the direct synthesis of acetic acid

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Journal of Natural Gas Chemistry 2008年第3期17卷 213-224页

作者： Hamid reza Arandiyan Matin Parvari Chemical Engineering Department Iran University of Science and Technology

In this study, mixed metal oxides developed with a perovskite-type structure that show great potential for use in catalysis. Perovskite oxide catalysts with the composition LaMoxV1-xOn （x = 0.1, 0.3, 0.5, 0.7, and 0.9） have been synthesized by the sol-gel method and then used in the ethane dry reforming reaction for the direct synthesis of acetic acid. The influence of the nature of the metallic source （metal, nitrate, acetylacetonate, and ammonium） on gel formation has been studied by Fourier-transform infrared spectroscopy （FT-IR） and thermogravimetric analysis （TGA-DTA）. After calcination, the obtained perovskites were characterized by X-ray diffraction （XRD） and energy-dispersive X-ray spectrometry （EDS） coupled with scanning electron microscopy （SEM）. The catalysts were then subjected to thermo-programmed reduction （TPR）. The surface area （BET） was found to increase from 2.6 m^2/g （x = 0.1） to 5.1 m2/g （x = 1.0） with increasing molybdenum content following calcinations at 750 °C, and pure LaMoxV1-xOn perovskite was obtained with good homogeneity. The catalysts have been characterized by XRD, SEM, EDS, and carbon analysis （CA）. The results indicate that through this synthesis it is possible to obtain highly crystalline, homogeneous and pure solids, with well-defined structures. The direct synthesis of acetic acid from ethane over the perovskite catalysts was studied at temperatures between 450 and 850 °C and elevated pressures between 1 and 8 bar. It was found that the yield of acetic acid and the selectivity of its formation could be increased by incorporating more molybdenum into the perovskite structure. The experimental studies have shown that the calcination temperature and the molybdenum content have a significant influence on the catalytic activity. Amongst the catalysts tested, LaMo0.7V0.3O4.2 exhibited the best activity and stability.

关键词： acetic acid catalyst perovskite activity LaMoxV1-xOn

Generating one-,two-,three-and four-scroll attractors from a novel four-dimensional smooth autonomous chaotic system

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Chinese Physics B 2010年第6期19卷 106-114页

作者： Sara Dadras Hamid reza Momeni Automation and Instruments Lab Electrical Engineering DepartmentTarbiat Modares UniversityP.O.Box 14115-143TehranIran

A new four-dimensional quadratic smooth autonomous chaotic system is presented in this paper, which can exhibit periodic orbit and chaos under the conditions on the system parameters. Importantly, the system can generate one-, two-, three- and four-scroll chaotic attractors with appropriate choices of parameters. Interestingly, all the attractors are generated only by changing a single parameter. The dynamic analysis approach in the paper involves time series, phase portraits, Poincare maps, a bifurcation diagram, and Lyapunov exponents, to investigate some basic dynamical behaviours of the proposed four-dimensional system.

关键词： new smooth autonomous four-dimensional chaotic system multi-scroll chaotic attractor Poincare mapping bifurcation Lyapunov exponent

Perfect GMR effect in gapped graphene-based ferromagnetic normal ferromagnetic junctions

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Chinese Physics B 2015年第4期24卷 405-410页

作者： Hossein Karbaschi Gholam reza Rashedi Department of Physics University of Isfahan

We investigate the quantum transport property in gapped graphene-based ferromagnetic/normal/ferromagnetic （FG/NG/FG） junctions by using the Dirac-Bogoliubov-de Gennes equation. The graphene is fabricated on SiC and BN substrates separately, so carders in FG/NG/FG structures are considered as massive relativistic particles. Transmission prob- ability, charge, and spin conductances are studied as a function of exchange energy of ferromagnets （h）, size of graphene gap, and thickness of normal graphene region （L） respectively. Using the experimental values of Fermi energy in the normal graphene part （EFN - 400 meV） and energy gap in graphene （260 meV for SiC and 50 meV for BN substrate）, it is shown that this structure can be used for both spin-up and spin-down polarized current. The latter case has different behavior of gapped FG/NG/FG from that of gapless FG/NG/FG structures. Also perfect charge giant magnetoresistance is observed in a range of E FN - mv 2 F〈h〈E FN＋mv 2 F.

关键词： graphene spin-polarized current giant magnetoresistance nanoscale structures

Characterization of Cysteine Coated Magnetite Nanoparticles as MRI Contrast Agent

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Nano-Micro Letters 2012年第3期4卷 180-183页

作者： reza Ahmadi Ning Gu Hamid reza Madaah Hosseini Department of Materials Science and Engineering Sharif University of Technology Research Center for Molecular and Cellular Imaging Tehran University of Medical Sciences Jiangsu Key Laboratory of Biomaterials and Devices

In this work,a kind of stabilized ferrofluid based on magnetite nanoparticles(mean core and its coating size about 21.9 and 1.6 nm,respectively)was synthesized via coprecipitation *** was used as surfactant due to its proper conjunction to the surface of magnetite *** density and synthesized ferrofluids were characterized by using transmission electron microscope,thermogravimetry analysis,dynamic light scattering and fourier transform infrared spectroscopy *** resonance imaging studies show that the synthesized ferrofluid can be used as a potential contrast enhancement agent especially for imaging lymphatic system.

关键词： Magnetite Co-precipitation Cysteine MRI

Random vibration of nonlinear structures with stiffness and strength deterioration by modified tail equivalent linearization method

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Earthquake Engineering and Engineering Vibration 2019年第3期18卷 597-610页

作者： reza Raoufi Mohsen Ghafory-Ashtiany Department of Civil Engineering Ahvaz Branch Islamic Azad University Ahvaz Iran International Institute of Earthquake Engineering and Seismology (IIEES) Member: Iranian Earthquake Engineering Association (IEEA)

In this research the tail equivalent linearization method (TELM) has been extended to study structures with degrading materials. The responses of such structures to excitations are non-stationary, even if the excitations are stationary. Non-stationary behavior of the system cannot be considered by conventional TELM. Applying the conventional TELM, the only distinction in the design point excitation for two stationary excitations with diff erent durations is in the addition of a zero value part at the beginning of the design point of the longer excitation. This means that the failure probability is the same for the non-stationary systems under excitations with diff erent durations. Therefore, this solution cannot be correct. In this study, in using TELM for systems with degrading materials, hysteretic energy is replaced by average hysteretic energy, calculated by averaging the obtained hysteretic energy of the structure subjected to a few random sample load realization. In this way, the degradation parameters under design point coincide with those under sample load realizations. Since the average of the hysteretic energy is converges very fast, the modifi ed TELM only requires about tens to hundreds solutions of the response in addition to the ordinary calculations of conventional TELM.

关键词： Nonlinear linearization random vibration degradation

Second-order cone AC optimal power flow: convex relaxations and feasible solutions

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Journal of Modern Power Systems and Clean Energy 2019年第2期7卷 268-280页

作者： Zhao YUAN Mohammad reza HESAMZADEH Department of Electric Power and Energy Systems KTH Royal Institute of Technology

Optimal power flow(OPF) is the fundamental mathematical model to optimize power system *** on conic relaxation, Taylor series expansion and McCormick envelope, we propose three convex OPF models to improve the performance of the second-order cone alternating current OPF(SOC-ACOPF) model. The underlying idea of the proposed SOC-ACOPF models is to drop assumptions of the original SOC-ACOPF model by convex relaxation and approximation methods.A heuristic algorithm to recover feasible ACOPF solution from the relaxed solution of the proposed SOC-ACOPF models is developed. The proposed SOC-ACOPF models are examined through IEEE case studies under various load scenarios and power network congestions. The quality of solutions from the proposed SOC-ACOPF models is evaluated using MATPOWER(local optimality) and LINDOGLOBAL(global optimality). We also compare numerically the proposed SOC-ACOPF models with other two convex ACOPF models in the *** numerical results show robust performance of the proposed SOCACOPF models and the feasible solution recovery algorithm.

关键词： Optimal power flow Conic relaxation McCormick envelope Taylor series expansion Feasible solution