检索结果-南通市图书馆

Theoretical & Applied mechanics Letters 2023年第6期13卷 484-493页

作者： m.Javidan m.gorji-bandpy A.Al-Araji Department of mechanical Engineering Babol Noshirvani University of TechnologyBabol 47148-71167Iran

The present study discusses the thermal performance of the receiver tube,which contains a wall with various fin shapes in the parabolic trough *** fins and bulge surfaces of the inner wall of the receiver tube increase the turbulent fluid *** pursuance of uniform distribution of heat transfer,various fin shapes such as square-shape,circle-shape,triangle-shape,and combined square-circle shapes were inserted,examined,and compared.A study of the temperature differences and fluid flow is meaningful for this project therefore finite volume method was used to investigate heat ***,hybrid Nano-Fluid AL_(2)O_(3-)CuO,TiO_(2-)Cu,and AgmgO were applied to increase thermal *** the combined square-circle-shaped fin was inserted,the thermal peak of fluid flow in the receiver tube was lower than the other studied fin shapes by almost 1%.Besides,the hybrid nano-fluid Ag-mgO Syltherm-oil-800 has lower thermal waste in comparison to others by more than 3%.

关键词： Parabolic trough collectors Hybrid nano-fluid Syltherm oil-800 Ag-mgO Thermal performance

Free convection of nanofluid filled enclosure using lattice Boltzmann method (LBm)

在线全文

学校读者我要写书评

暂无评论

Applied mathematics and mechanics(English Edition) 2013年第7期34卷 833-846页

作者： m.SHEIKHOLESLAmI m.gorji-bandpy G.DOmAIRRY Department of mechanical Engineering Babol Noshirvani University of Technology

The lattice Boltzmann method （LBm） is used to examine free convection of nanofluids. The space between the cold outer square and heated inner circular cylinders is filled with water including various kinds of nanoparticles： TiO2, Ag, Cu, and A1203. The Brinkman and maxwell-Garnetts models are used to simulate the viscosity and the effective thermal conductivity of nanofluids, respectively. Results from the performed numerical analysis show good agreement with those obtained from other numerical meth- ods. A variety of the Rayleigh number, the nanoparticle volume fraction, and the aspect ratio are examined. According to the results, choosing copper as the nanoparticle leads to obtaining the highest enhancement for this problem. The results also indicate that the maximum value of enhancement occurs at λ =2.5 when Ra = 106 while at A = 1.5 for other Rayleigh numbers.

关键词： lattice Boltzmann method (LBm) nanofluid natural convection concentric annular cavity

Comparison between the volumetric flow rate and pressure distribution for different kinds of sliding thrust bearing

在线全文

学校读者我要写书评

暂无评论

Propulsion and Power Research 2015年第2期4卷 84-90页

作者： O.Pourmehran m.Rahimi-gorji m.gorji-bandpy m.Baoub Faculty of mechanical Engineering Babol Noshirvani University of TechnologyBabolIran Faculty of mechanical Engineering Shahrood University of TechnologyShahroodIran

In this paper a hydrodynamic journal sliding bearing,forming with two nonparallel surfaces that the lower surface moves with a unidirectional velocity and the upper surface is stationary shaped with exponential geometry is verified *** values of volumetric flow rate and distribution of pressure for incompressible lubricant flow between two supports in several conditions of velocity with different variables are *** results indicate that by increasing the amount of constant(m),the maximum oil pressure in the bearing will face an extreme decrease,and also by increasing theαcoefficient,the rate of volumetric flow rate will decrease.

关键词： Non-parallel plate bearing Hydrodynamic sliding bearing Incompressible lubricant flow Volumetric flow rate Exponential geometry

Application of volume of fluid method for simulation of a droplet impacting a fiber

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Propulsion and Power Research 2016年第2期5卷 123-133页

作者： m.Khalili H.Yahyazadeh m.gorji-bandpy D.D.Ganji Deparment of mechanical Engineering Babol University of TechmologyP.O.Box 484BabolMazandaranlram

In the present work,impact of a Newtonian drop on horizontal thin fibers withcircular cross section is simulated in 2D *** numerical simulations of the phenomenaare carried out using volume of fluid(VOF)method for tracking the free surface *** of a Newtonian droplet on a circular thin fiber(350 um radius)*** main focus of this simulation is to acquire threshold radius and velocity of adrop which is entirely captured by the *** model agrees well with the experiments anddemonstrates the threshold radius decreased generally with the increase of impact *** words,for velocity larger than threshold velocity of capture perhaps only a small portionof fluid is stuck on the solid and the rest of the drop is ejected for impact velocity smaller thancritical velocity the drop is totally *** threshold velocity has been determined whenthe impact is centered.

关键词： lmpact Newtonian drop Volume of fluid(VOF) Numerical simulation OpenFoam

Influence of cerium ions on structure-dependent magnetic properties of Ba-Sr m-type hexaferrite nanocrystals

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第2期42卷 364-372,I0005页

作者： Ram A.Pawar Sunil m.Patange P.m.Dighe Sher Singh meena Abdullah GAl-Sehemi mehboobali Pannipara Santosh S.Jadhav Department of Physics ArtsCommerce and Science CollegeAhmednagar413711MaharashtraIndia Department of Physics Shri Krishna MahavidyalayaGunjotiDistOsmanabad413606MaharashtraIndia Padmashri Vikhe Patil College of Arts Science and CommercePravaranagarA/P.Loni(Kd)Tal.RahataDistAhmednagar413713MaharashtraIndia Solid State Physics Division Bhabha Atomic Research CentreMumbai400085MaharashtraIndia Department of Chemistry King Khalid UniversityAbha61413Saudi Arabia Department of Physics D.S.M's ArtsCommerce and Science CollegeJintur431509MaharashtraIndia

The present study is a systematic effort to investigate the structure-sensitive magnetic parameters of Ce^(3+) substituted Ba-Sr hexaferrite nanocrystals chemically formulated as Ba_(0.5)Sr_(0.5)Ce_(x)Fe_(12-x)O_(19) where x=0.0-0.2 with Δx=*** hexaferrite powders were prepared using the sol-gel self-ignition route and structurally characterized by means of powder X-ray diffraction and Fourier transform infrared *** creation of the m-type hexaferrite phase within the synthesized samples was revealed from the Rietveld refinement of the X-ray *** occurrence of a secondary phase of CeO_(2) was revealed within the hexaferrites for the substitution,x> *** refined X-ray diffraction data were utilized to compute the lattice parameters,X-ray density,and lattice parameter *** crystal structure plotted from the refined XRD data reveals the occupancy of the ions at different lattice *** XPS data of the hexaferrite were analyzed to confirm the oxidation states of the constituent *** nanocrystalline nature of the hexaferrites was revealed from the crystallite sizes calculated using Scherer's *** analysis of FTIR spectra confirms that only a fraction of Ce^(3+)accommodated in the lattice and the remaining Ce content reside in the form of the CeO_(2) *** morphology of the hexaferrites was analyzed from the FESEm profiles of the ferrite *** magnetic behavior study was performed by analyzing the Curie temperature,hysteresis loops,and hyperfine interactions by means of susceptibility,V.S.m,and mossbauer spectroscopy,*** hexaferrites with increasing coercivity,decreasing saturation magnetization,and decreasing Curie temperature are reported in the *** substituted Ce^(3+)ions inhibit the grain growth and create lattice imperfections giving rise to hexaferrites with tuned magnetic parameters suitable for different applications.

关键词： Ba-Sr hexaferrite Ce^(3+)substitution XPS Saturation magnetization Coercivity m?ssbauer spectroscopy

Solution of nonlinear cubic-quintic Duffing oscillators using He’s Energy Balance method

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第9期10卷 1263-1268页

作者： D.D.GANJI m.gorji S.SOLEImANI m.ESmAEILPOUR Department of mechanical Engineering University of Mazandaran

In this study, He's Energy Balance method (EBm) was applied to solve strong nonlinear Duffing oscillators with cubic-quintic nonlinear restoring force. The complete EBm solution procedure of the cubic-quintic Duffing oscillator equation is presented. For illustration of effectiveness and convenience of the EBm, different cases of cubic-quintic Duffing oscillator with different parameters of α,β and γ were compared with the exact solution. We found that the solutions were valid for small as well as large amplitudes of oscillation. The results show that the EBm is very convenient and precise, so it can be widely applicable in engineering and other sciences.

关键词：能量平衡法五次非线性振荡器立方 Duffing振子循证医学强非线性振子方程

Analytical solution for laminar flow through leaky tube

在线全文

学校读者我要写书评

暂无评论

Applied mathematics and mechanics(English Edition) 2011年第1期32卷 69-74页

作者： m.gorji m.ALIPANAH m.SHATERI E.FARNAD Department of mechanical Engineering Babol University of Technology Water and Westwater Company

The laminar flow through a leaky tube is investigated, and the momentum and conservation of energy equations are solved analytically. By using the Hagen-Poiseuille velocity profile and defining unknown functions for the axial and radial velocity compo- nents, the pressure and mass transfer equations are obtained, and their profiles are plotted according to different parameters. The results indicate that the axial velocity, the radial velocity, the mass transfer parameter, and the pressure in the tube decrease as the fluid moves along the tube.

关键词： leaky tube permeability mass transfer laminar flow analytical solution

Frequency-dependent viscoelasticity effects on the wave attenuation performance of multi-layered periodic foundations

在线全文

学校读者我要写书评

暂无评论

Applied mathematics and mechanics(English Edition) 2024年第3期45卷 407-424页

作者： m.SAFI m.VAKILIFARD m.J.mAHmOODI Faculty of Civil Water&Environmental EngineeringShahid Beheshti UniversityTehran ***Iran Faculty of mechanical and Energy Engineering Shahid Beheshti UniversityTehran ***Iran

In this paper,layered periodic foundations(LPFs)are numerically examined for their responses to longitudinal and transverse modes in the time and frequency *** different unit-cells,i.e.,2-layer,4-layer,and 6-layer unit-cells,comprising concrete/rubber,concrete/rubber/steel/rubber,and concrete/rubber/steel/rubber/lead/rubber materials,respectively,are taken into ***,the viscoelasticity behavior of the rubber is modeled with two factors,i.e.,a frequency-independent(FI)loss factor and a linear frequency-dependent(FD)loss *** the extraction of the complex dispersion curves and the identification of the band gaps(BGs),the simulations of wave transmission in the time and frequency domains are performed using the COmSOL *** parametric studies evaluate the effects of the rubber viscoelasticity models on the dispersion curves and the wave transmission for the longitudinal and transverse *** results show that considering the rubber viscoelasticity enhances the wave attenuation ***,the transverse-mode damping is more sensitive to the viscoelasticity model than its longitudinal *** 6-layer unit-cell LPF exhibits the lowest BG,ranging from 4.8 Hz to 6.5 Hz.

关键词： layered metamaterial periodic foundation complex dispersion curve wave transmission diagram

Engineering of efficient visible light photocatalysts:Ti_(1-x+y)Cu_(x)La_(y)O_(2)(x=0.03;y=0,0.005,0.01) compositions

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第3期42卷 497-505,I0003页

作者： S.m.Yakout A.m.Youssef Inorganic Chemistry Department National Research Centre(NRC)El Buhouth StDokkiCairo12622Egypt

In dye-photocatalysis, widening the wavelengths absorption range of catalysts as well as aborting the recombination of the photoexcited charge carriers(electrons-holes pairs) are of paramount *** the current study, we report the photocatalytic characteristics of four compositions composed of TiO_(2),Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders for two harmful dyes(Congo red and methylene blue). The X-ray diffraction technique verified the configuration of mixed anatase and rutile phases in pure TiO_(2)and Ti_(0.97)Cu_(0.03)O_(2)powders while Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders possess anatase phase only. The changes of the band gap structure and dimensions of the unit cell volume of TiO_(2)confirm the substitution of Ti^(4+)sites by Cu^(2+)and La^(3+)ions. Remarkable widening of wavelengths absorption with formation of long absorption tails were found in TiO_(2)(3.13 e V) through insertion of La^(3+)plus Cu^(2+)ions. Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)samples exhibit a visible light band gap of 2.3 and 2.7 e V, respectively. Based on SEm images, incorporation of Cu^(2+)and La^(3+)ions influences the surface morphology of TiO_(2). The resulting Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders present enhanced photocatalytic activity towards Congo red dye degradation compared to pure one under natural solar spectrum. The best Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)catalyst exhibits superior photocatalytic activity of 96% for 10 ppm CR dye in 20 min as well as above average photocatalytic efficiency of 63% for 30 ppm CR dye in 120 min. As well, it showed acceptable photodegradation activity of 52% for 30 ppm mB solution in 140 min of sunlight irradiation. The heightened photodegradation efficiency of Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)catalyst can be clarified in terms of higher ch

关键词： Semiconductor TiO_(2) Rare earths Congo red methylene blue Solar spectrum Photodegradation

Nonlinear dynamic modeling of planar moving Timoshenko beam considering non-rigid non-elastic axial effects

在线全文

学校读者我要写书评

暂无评论

Applied mathematics and mechanics(English Edition) 2024年第3期45卷 479-496页

作者： m.ABBASI GAVARI m.R.HOmAEINEZHAD Faculty of mechanical Engineering K.N.Toosi University of TechnologyTehran 19991-43344Iran

Due to the importance of vibration effects on the functional accuracy of mechanical systems,this research aims to develop a precise model of a nonlinearly vibrating single-link mobile flexible *** manipulator consists of an elastic arm,a rotary motor,and a rigid carrier,and undergoes general in-plane rigid body motion along with elastic transverse *** accurately model the elastic behavior,Timoshenko’s beam theory is used to describe the flexible arm,which accounts for rotary inertia and shear deformation *** applying Newton’s second law,the nonlinear governing equations of motion for the manipulator are derived as a coupled system of ordinary differential equations(ODEs)and partial differential equations(PDEs).Then,the assumed mode method(Amm)is used to solve this nonlinear system of governing equations with appropriate shape *** assumed modes can be obtained after solving the characteristic equation of a Timoshenko beam with clamped boundary conditions at one end and an attached mass/inertia at the *** addition,the effect of the transverse vibration of the inextensible arm on its axial behavior is *** the axial rigidity,the effect makes the rigid body dynamics invalid for the axial behavior of the ***,numerical simulations are conducted to evaluate the performance of the developed model,and the results are compared with those obtained by the finite element *** comparison confirms the validity of the proposed dynamic model for the *** to the mentioned features,this model can be reliable for investigating the system’s vibrational behavior and implementing vibration control algorithms.

关键词： planar moving Timoshenko beam non-rigid non-elastic axial effect as-sumed mode method(Amm) nonlinear motion analysis