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Numerical modeling of vibration fatigue of viscoelastic pipelines conveying pulsating fluid flow

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International Journal of modeling, Simulation, and Scientific Computing 2020年第3期11卷 117-134页

作者： kh.m.Komilova Department of Higher mathematics Tashkent Institute of Irrigation and Agricultural mechanization Engineers Tashkent Uzbekistan

The effect of investigation results on viscoelastic properties of the material and bases on vibration fatigue of a pipeline conveying pulsating fluid flow is given in the paper.A mathematical model of viscoelastic pipeline vibrations based on the theory of beams was developed when a pulsating fluid flows through it.A computational algorithm has been developed to solve vibration problems of composite pipelines conveying pulsating *** and amplitude-time characteristics of vibrations of composite pipelines conveying pulsating fluid were studied at wide range of parameters variation of deformable systems and fluid flow.

关键词： Numerical simulation vibration pulsating fluid pipeline critical rate

The micropolar fluid model for blood flow through a tapered artery with a stenosis

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Acta mechanica Sinica 2008年第6期24卷 637-644页

作者： kh.S.mekheimer m.A.El Kot Department of mathematics Faculty of ScienceAl-Azhar UniversityNasr CityCairo 11884Egypt Department of mathematics Faculty of EducationSuez Canal UniversitySuezEgypt

A micropolar model for axisymmetric blood flow through an axially nonsymmetreic but radially symmetric mild stenosis tapered artery is presented. To estimate the effect of the stenosis shape, a suitable geometry has been considered such that the axial shape of the stenosis can be changed easily just by varying a parameter （referred to as the shape parameter）. The model is also used to study the effect of the taper angle Ф. Flow parameters such as the velocity, the resistance to flow （the resistance impedance）, the wall shear stress distribution in the stenotic region and its magnitude at the maximum height of the stenosis （stenosis throat） have been computed for different values of the shape parameter n, the taper angle Ф, the coupling number N and the micropolar parameter m. It is shown that the resistance to flow decreases with increasing the shape parameter n and the micropolar parameter m while it increases with increasing the coupling number N. So, the magnitude of the resistance impedance is higher for a micropolar fluid than that for a Newtonian fluid model. Finally, the velocity profile, the wall shear stress distribution in the stenotic region and its magnitude at the maximum height of the stenosis are discussed for different values of the parameters involved on the problem.

关键词： micropolar fluid Blood flow Tapered artery

SYNTHESIS OF SOLUBLE POLY(3,4-DIHYDROXY-o-TOLYLENE):REDOX POLYmER

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Chinese Journal of Polymer Science 2006年第1期24卷 41-46页

作者： sad moulay Fatima m'zyène Laboratoire de Chimie-Physique moléculaire et macromoléculaire Faculté des Sciences de l'Ingénieur Département de Chimie Industrielle Université de BlidaRoute de SoumèaB.P.270Blida 09000Algeria. Laboratoire de Chimie-Physique moléculaire et macromoléculaire Faculté des Sciences de l'Ingénieur Département de Chimie Industrielle Université de BlidaRoute de SoumaB.P.270Blida 09000Algeria.

Conventional chloromethylation, paraformaldehyde/hydrogen chloride in acetic acid medium, was applied to 1,2- dimethoxybenzene. Chloroform-soluble poly（3,4-dimethoxy-o-tolylene） was obtained with an intrinsic viscosity of 0.034 dL g^-1. The polymer was evaluated as a condensation redox polymer precursor formed by a Friedel-Crafts reaction. Cleavage of the methoxy groups present in this polymer resulted in poly（3,4-dihydroxy-o-tolylene） which manifested a great air-oxidation resistance. The redox property of the latter polymer was found to be 1017 mV by potentiometric titration with 0.05 N ceric ammonium nitrate at 25℃. This midpotential was compared to that of catechol, a monomeric analogue, under the same titration conditions.

关键词： Poly(3,4-dimethoxy-o-tolylene) Poly(3,4-dihydroxy-o-tolylene) Redox polymer.

Influence of magnetic field and Hall currents on blood flow through a stenotic artery

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Applied mathematics and mechanics(English Edition) 2008年第8期29卷 1093-1104页

作者： kh.S.mekheimer m.A.El Kot Department of mathematics Faculty of ScienceAl-Azhar University Nasr City 11884CairoEgypt Department of mathematics Faculty of EducationSuez Canal UniversitySuezEgypt

A micropolar model for blood simulating magnetohydrodynamic flow through a horizontally nonsymmetric but vertically symmetric artery with a mild stenosis is presented. To estimate the effect of the stenosis shape, a suitable geometry has been considered such that the horizontal shape of the stenosis can easily be changed just by varying a parameter referred to as the shape parameter. Flow parameters, such as velocity, the resistance to flow （the resistance impedance）, the wall shear stress distribution in the stenotic region, and its magnitude at the maximum height of the stenosis （stenosis throat）, have been computed for different shape parameters, the Hartmann number and the Hall parameter. This shows that the resistance to flow decreases with the increasing values of the parameter determining the stenosis shape and the Hail parameter, while it increases with the increasing Hartmann number. The wall shear stress and the shearing stress on the wall at the maximum height of the stenosis possess an inverse characteristic to the resistance to flow with respect to any given value of the Hartmann number and the Hall parameter. Finally, the effect of the Hartmann number and the Hall parameter on the horizontal velocity is examined.

关键词： stenotic artery Hall currents blood flow

Effect of coaxial laser cladding parameters on bead formation

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International Journal of minerals,metallurgy and materials 2017年第5期24卷 550-556页

作者： A.I.Noskov A.kh.Gilmutdinov R.m.Yanbaev Kazan National Research Technical University 10 Karl Marx Str. Kazan 420111 Republic of Tatarstan Russian Federation

We investigated the shape and morphology of nickel-based powder particles (Sulzer metco) and coatings produced by laser gas-powder deposition onto steel substrates. Laser deposition was performed using an LC-10 IPG-Photonics laser complex equipped with a 10-kW fiber laser. The shape and microstructure of the samples were studied using optical and electronic microscopy and X-ray diffraction analysis. The results showed that the deposition speed and laser power significantly influenced the shape and size of the beads. The depth of diffusion of nickel into the steel substrate after deposition was less than 20 μm; the microstructure of the resulting coating was fcc Fe3Ni. As a result, detailed information about the form and shape of the filler powder, modes of its deposition, and the resulting coating structure was obtained; this information is important for the production of high-quality products by additive technologies.

关键词： laser cladding additive manufacturing microstructure morphology bead formation

Effects of magnetic field,porosity,and wall properties for anisotropically elastic multi-stenosis arteries on blood flow characteristics

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Applied mathematics and mechanics(English Edition) 2011年第8期32卷 1047-1064页

作者： kh.S.mEkhEImER m.H.HAROUN m.A.ELKOT Department of mathematics Faculty of Science Al-Azhar University Department of mathematics Faculty of Education Ain Shams University Department of mathematics Faculty of Science Suez Canal University

A mathematical model for blood flow through an elastic artery with multistenosis under the effect of a magnetic field in a porous medium is presented. The considered arterial segment is simulated by an anisotropically elastic cylindrical tube filled with a viscous incompressible electrically conducting fluid representing blood. An artery with mild local narrowing in its lumen forming a stenosis is analyzed. The effects of arterial wall parameters represent viscoelastic stresses along the longitudinal and circumferential directions T t and T θ , respectively. The degree of anisotropy of the vessel wall γ, total mass of the vessel, and surrounding tissues m and contributions of the viscous and elastic constraints to the total tethering C and K respectively on resistance impedance, wall shear stress distribution, and radial and axial velocities are illustrated. Also, the effects of the stenosis shape m, the constant of permeability κ, the Hartmann number Ha and the maximum height of the stenosis size δ on the fluid flow characteristics are investigated. The results show that the flow is appreciably influenced by surrounding connective tissues of the arterial wall motion, and the degree of anisotropy of the vessel wall plays an important role in determining the material of the artery. Further, the wall shear stress distribution increases with increasing T t and γ while decreases with increasing T θ , m, C, and K. Transmission of the wall shear stress distribution and resistance impedance at the wall surface through a tethered tube are substantially lower than those through a free tube, while the shearing stress distribution at the stenosis throat has inverse characteristic through totally tethered and free tubes. The trapping bolus increases in size toward the line center of the tube as the permeability constant κ increases and decreases with the Hartmann number Ha increased. Finally, the trapping bolus appears, gradually in the case of non-symmetric stenosis, and disap

关键词： stenosis degree of anisotropy free tube tethered tube trapping bolus

Electrical characterization of the organic semiconductor Ag/CuPc/Au Schottky diode

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Journal of Semiconductors 2011年第4期32卷 52-56页

作者： mutabar Shah m.H.sayyad kh.S.Karimov Ghulam Ishaq khan Institute of Engineering Sciences and Technology physical Technical Institute of Academy of Sciences

This paper reports on the fabrication and investigation of a surface-type organic semiconductor copper phthalocyanine（CuPc） based diode.A thin film of CuPc of thickness 100 nm was thermally sublimed onto a glass substrate with preliminary deposited metallic electrodes to form a surface-type Ag/CuPc/Au Schottky *** current-voltage characteristics were measured at room temperature under dark *** barrier height was calculated as 1.05 *** values of mobility and conductivity was found to be 1.74×10;cm;/（V·s） and 5.5×10;Ω;·cm;,*** low voltages the device showed ohmic conduction and the space charge limited current conduction mechanisms were dominated at higher voltages.

关键词： Schottky diode copper phthalocyanine thin film organic semiconductor mobility

Surface-type humidity sensor based on cellulose-PEPC for telemetry systems

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Journal of Semiconductors 2011年第1期32卷 103-107页

作者： kh.S.Karimov m.saleem T.A.Qasuria m.Farooq GIK Institute of Engineering Sciences and Technology physical Technical Institute Aini St.299/1Dushanbe734063Tajikistan

Au/cellulose-PEPC/Au surface-type humidity sensors were fabricated by drop-casting cellulose and poly-N-epoxypropylcarbazole （PEPC） blend thin films. A blend of 2wt% of each cellulose and PEPC in benzol was used for the deposition of humidity sensing films. Blend films were deposited on glass substrates with preliminary deposited surface-type gold electrodes. Films of different thicknesses of cellulose and PEPC composite were deposited by drop-casting technique. A change in electrical resistance and capacitance of the fabricated devices was observed by increasing the relative humidity in the range of 0-95% RH. It was observed that the capacitances of the sensors increase, while their resistances decrease with increasing the relative humidity. The sensors were connected to op-amp square wave oscillators. It was observed that with increasing the relative humidity, the oscillator＇s frequencies were also increased in the range of 4.2-12.0 khz for 65μm thick film sample, 4.1-9.0 khz for 88μm thick film sample, and 4.2-9.0 khz for 210μm sample. Effects of film thickness on the oscillator＇s frequency with respect to humidity were also investigated. This polymer humidity sensor controlled oscillator can be used for short-range and long-range remote systems at environmental monitoring and assessment of the humidity level.

关键词： surface-type sensor: cellulose poly-N-epoxvoropylcarbazole humidity sensor controlled oscillator

A Boundary Value Problem for the Degenerated Elliptic Equation with Singular Coefficient and Spectral Parameter

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Journal of Partial Differential Equations 2018年第3期31卷 214-223页

作者： RUZIEV m.kh. Institute of mathematics Academy of Science of the Republic of Uzbekistan Mirzo Ulugbek str. 81 100170 Tashkent Uzbekistan.

In this paper, the Dirichlet problem in the vertical half-band for the degenerated elliptic equation with singular coefficient and spectral parameter is investigated. Using the Hankel transformation and the method of ... 详细信息

关键词： Half-band Hankel transformation series the Fourier method uniqueness existence