39 Works

Changes in rock permeability near wellbore due to operational loads

Vladimir Poplygin, Evgenii Riabokon, Mikhail Turbakov, Evgenii Kozhevnikov, Mikhail Guzev & H. Jing
The paper presents the results of studies of changes in the permeability of rocks in the bottomhole zone of wells in the process of oil production. Using the exponential equation for predicting the permeability of the rock with a change in reservoir pressure based on the data of well test data, an improved model is proposed. The developed model takes into account operational conditions that lead to a change in the structure of the rock...

Optimization of powder metallurgy process parameters to enhance the mechanical properties of AZ91 magnesium alloy

Naveen Kumar & Ajaya Bharti
In the present work, optimization of powder metallurgy process parameters, i.e., compaction pressure, sintering time, and sintering temperature, for magnesium alloy AZ91 is done using Taguchi Design of Experiment and ANOVA techniques. Regression equation for determining ultimate compressive stress and hardness of AZ91 Magnesium alloy was formulated and validated experimentally. Out of the nine sets of parameters present in the current design, H8 (450 MPa compaction pressure, 450° sintering temperature, and 60 minutes sintering time)...

On the problem of evaluating the behavior of multicomponent materials in mixed boundary conditions in contact problems

Vladimir Babeshko, O.V. Evdokimova & Olga Babeshko
For the purposes of evaluating the behavior of multicomponent materials under operating conditions, the paper for the first time constructs in general an exact solution of systems of Wiener-Hopf integral equations of arbitrary order. Systems of these equations arise in mixed problems of continuum mechanics for multicomponent materials of complex rheology. The cases of mixed boundary value problems are considered under the assumption that there is a change of boundary conditions on the inner or...

Epoxy-polyester coatings with additives of PTFE particles and nanoparticles of SiO2

G.V. Vaganov, V.V. Vaganov, A.Yu. Kolesnikova, E.A. Serikova & E.M. Ivan'kova
Hydrophobic and super-hydrophobic coatings based on epoxy-polyester powder compositions modified with polytetrafluoroethylene (PTFE) particles and nanoparticles silicon dioxide were obtained. The degree of hydrophobicity of the coatings depended on the concentration of PTFE particles. Coatings containing optimal amounts of PTFE exhibited superhydrophobic properties with a high contact angle of wetting with water up to 161° and a low roll angle <3°, while maintaining a high level of physical and mechanical properties of the coatings. The...

Wave propagation due to laser irradiation in viscoelastic thin metal film with fractional relaxation operator

Mohamed H. Hendy, Magdy A. Ezzat & Magdy M. Amin
In the present paper, the model of generalized thermo-viscoelastic theory with fractional relaxation operators is used to capture the microscale responses of viscoelastic metal film irradiated uniformly by a laser pulse heat flux with non-Gaussian form. Employing Laplace transform as a tool, the problem has been solved analytically in the transformed domain. The inverse transforms are obtained by using a numerical method based on Fourier expansion techniques. The effects of fractional relaxation operators and viscoelastic...

Influence of Fiber Length, Weight Percentage on Water Hyacinth Polymer Composite Material Properties– Aquatic Waste into Commercial Applications

A. Ajithram , J.T. Winowlin Jappes & I. Siva
The major factors that affect the properties of fiber-reinforced composites are the length and weight percentage of the fibers. In this work, aquatic wastewater hyacinth fiber is extracted from the parent plant to the novel way of the mechanical-based extraction process. Mechanical experiments like tensile, flexural, impact strength, and modulus are processed as per ASTM standards. Consequent mechanical properties, thermal properties, water, and chemical absorption test also studied these hyacinth fiber-reinforced composites. Then, the fractured...

The intermetallic compounds formation and mechanical properties of composites in the Ni-Al system

O.K. Kurapova, I.S. Smirnov, E.N. Solovyeva, Y.K. Konakov, T.L. Lomakina, A.G. Glukharev & K.V. Konakov
Aluminum-nickel (Al-Ni) based intermetallic compounds are regarded as the promising materials for high-temperature engineering applications, including harsh environments. So far, a satisfactory modeling has been done to analyze the structural properties, heats of formation, elastic properties and electronic energy band structures of Al-Ni intermetallic compounds. However, the experimental studies on Al-Ni intermetallic compounds formation and the data on the structure and mechanical properties are fragmentary in the literature. In the present work the intermetallic compounds...

Experimental Substantiation of The Possibility of Hydrolytic Lignin Using in the Architectural Electromagnetic Shielding Systems

O.V. Boiprav, N.N. Grinchik & G.A. Pukhir
The article presents the research results of electromagnetic radiation reflection and transmission characteristics in the frequency range 0.7–17.0 GHz of the hydrolytic lignin, impregnated to saturation with the electrolyte water solution, at different temperatures of this material. The research is aimed at simultaneously solving of two problems: 1) search for new inexpensive materials for electromagnetic shielding; 2) experimental substantiation of a new promising method of hydrolysis lignin utilization. Based on the research results, it’s possible...

Dynamic Modeling of Functionally Graded Beams Undergoing Mobile Mass

A. Elmeiche, M. Bouamama, A. A. Elhannani , A. Belaziz & A. Hammoudi
In this paper, the dynamic modeling of functionally graded beams subjected to a mobile mass is studied using modal analyzes. The material properties are assumed to vary continuously in the transverse direction according to an exponential law. A new simple shear deformation beam theory (SFPSDBT) has been formulated and employed in the study, taking into account the effect of the material inhomogeneity and as well the inertia of moving mass. The governing equations are derived...


samir zahaf, mouloud dahmane, Belaziz Azzeddine, Ismaïl Bouri & Nasreddine AFANE
Numerical modeling by the finite element method allows us to gain appreciable time, information, and details on mechanical phenomena (stresses, strains, load transfer, stress intensity factors, etc.) related to the behavior of the total hip replacement. Knowledge of stress intensities and their distribution in the cement fixing the cup is of great importance for understanding the condition in dress service of the prosthesis cup and its loosening. To do this, an analysis digital by the...

Analysis of CuCrZr/316L(N) bimetallic joint with and without Nickel inter-layer for plasma facing components

Pavel Piskarev, Aleksandr Gervash, S. Bobrov, Vladimir Ruzanov, Andrey Ogurski, Igor Mazul, Radmir Giniiatulin, B. Ermakov & Oleg Sevryukov
The work considers the CuCrZr/316L(N) bimetallic joint, which is obtained by diffusion bonding using hot isostatic pressing (HIP) and is a design element of the plasma-facing components (PFC) of a thermonuclear reactor. A comparative analysis of the specified bimetallic joint with a nickel interlayer obtained by different methods and without it, has been carried out. A study of the structure and elemental composition of the bimetallic joint was made, where the brittle zirconium phases were...

Glass Formation and Some Physical Properties in NaPO3 – LiF and NaPO3 – (0.4 AlF3 – 0.6 CaF2) Systems

Виктор Клинков & Vsevolod Archelkov
The area of glass formation in NaPO3–LiF–(0.4AlF3 – 0.6CaF2) system was determined. The glasses were synthesized using standard melt-quenching techniques. The concentration dependencies of glass transition temperature, refractive index, density, molar volume, microhardness and crystallization products were obtained. In (NaPO3)100-x–(LiF)x glass the linear decrease of noted parameters was observed. The LiF additives to the phosphate network caused the formation of “friable” glass network. In (NaPO3)100-x –(0.4AlF3 – 0.6CaF2)x system the concentration dependencies were more complex...

Experimental investigation of mechanical behavior of honeycomb sandwich composite under three-point bending fatigue

Hocine Mzad
The present experimental work deals with the mechanical fatigue behavior under 3-point bending stress of composite aluminum panels with an aramid honeycomb core. The testing conditions (applied load and frequency), under cyclic loading, the analysis of rigidity loss, and the damage modes are the tools for this experimental investigation. The specimens consist of aluminum sheets, one millimeter thick each for the skins, and a honeycomb aramid structure, eight millimeters high for the core. As a...

An out-of-plane oscillating beam nanoresonator with ultrahigh intrinsic quality factor

Manh Hoang Chu, Duong Nguyen Van & Dang Van Hieu
An out-of-plane oscillating beam nanoresonator with the ultrahigh intrinsic quality factor based on the motion transformation mechanism from torsion into rotation is reported. The nanoresonator is composed of two resonant beams which are mechanically coupled through two spring beams oscillating in an out-of-phase torsional mode. The out-of-phase torsional oscillation of the two spring beams forms a stationary point in the middle of a supporting beam, which minimizes anchor loss. The low thermoelastic damping (TED) in...

Seismic behavior of heritage building with isotropic and orthotropic material properties: a comparative analysis

Kamran , shakeel ahmad & REHAN A KHAN
Restoration and retrofitting of heritage buildings is a complex analysis. In actual practice, building materials of heritage masonry buildings are anisotropic. However, in practice, these building materials had been considered isotropic to optimize the analysis. The present study is a comparative analysis of these two approaches. A heritage school building in northern India underlying seismic zone IV has been considered for the analysis. The seismic performance analysis of the buildings has been carried out through...


S.V. Kirikov, V.N. Perevezentsev, A.S. Pupynin & J.V. Svirina
The arrest conditions due to the action of the elastic fields of a dipole of wedge disclinations and a planar shear mesodefect are considered for dislocation cracks propagating under external loading. The regions of stable cracks existence are determined using the method of configurational force in the configuration space of the system parameters (the mesodefect strength vs the Burgers vector of the crack) and the maps of the cracks lengths distribution were plotted at various...

Elasticity of thin dilatational disk in an isotropic half-space

T. Nguyen Van, A.L. Kolesnikova & A.E. Romanov
In this article, the solution to the elasticity boundary-value problem for an infinitesimally thin dilatational disk (ITDD) embedded in an elastically isotropic half-space is presented. The plane of the disk is parallel to the free surface. To solve the boundary value problem, the method of virtual defects is used. The image (mirror) ITDD and radial Somigliana dislocation loops (RSDLs), distributed continuously over the free surface coaxially with the ITDD, are chosen as virtual defects. The...


A. Heydari
This article is concerned with the vibration control of a bidirectionally graded beam supported on torsion spring hinges using a lumped mass damper. The conventional mixing rule is used to model the material gradation in the thickness direction. The material gradation in the axial direction is modeled by an exponential function. The spectral Ritz method is employed to minimize the total potential energy and calculate the fundamental angular frequency of free vibration and the corresponding...

Unstable plastic flow in structural materials: time series for analysis of experimental data

Ekaterina Zaitseva, Anna Shmeleva & Владислав Казанков
The present study provides the mathematical description of changing metals characteristics during exploitation, as well as identifies behaviors and features during plastic deformation. Modern experimental facilities allow to conduct a full-scale experiment, record the effects observed, determine the patterns of materials behavior of and their alloys to predict the occurrence of unstable plastic flow. The arrays of experimental data obtained in the format of discrete values were processed with the wave-record method for the data...

Non-equilibrium phonon gas in a chalcogenide semiconductor with exponential temperature dependence of conductivity

Karim Mynbaev & N.V. Sovtus
The distribution function for a phonon gas in the non-equilibrium case of current crowding in a chalcogenide glassy semiconductor is considered. The approximate internal energy of the gas and its heat capacity is calculated. The change in the heat capacity caused by phase changes, which according to the results of the numerical calculations, are similar to the second-order phase transition, is analyzed. The law of temperature variation with time is calculated for a homogeneous current...

Study numerical and experimental of stress concentration factor on isotropic plate with hole

M.N. Misbah, Rizky Chandra Ariesta, T. Yulianto, Dony Setyawan & W.H.A. Putra
The stress concentration factor (SCF) can lead to the failure of ship construction. That problem can occur with hotspot stress expansion in the local area because of the acting load and structural details shapes. However, there is no method for the asses of structure design failure in the minor openings such as a dry hole and scallop dimension. Furthermore, the research aims for evaluating stress concentration performed using the diameter and width (d/W) ratio. The...

Influence of Ni-Al interphase boundary orientation on the interdiffusion rate at temperatures above aluminum melting point: a molecular dynamics study

Gennady Poletaev & Роман Ракитин
The influence of the orientation of Ni-Al interphase boundary relative to the nickel crystal lattice on the intensity of interdiffusion at temperatures above the melting temperature of aluminum was studied by the method of molecular dynamics. It was observed that the boundary between the crystalline and liquid phases was, in fact, shifted by two or three atomic planes into the aluminum phase – a thin layer of aluminum near the boundary retained a crystalline structure...

Effect of Si+ ion irradiation of α-Ga2O3 epitaxial layers on their hydrogen sensitivity

Nikita Yakovlev, Aleksei Almaev, Pavel Butenko, Alexey Mikhaylov, Aleksey Pechnikov, S.I. Stepanov, Roman Timashov, Andrew Chikiryaka & Vladimir Nikolaev
The effect of Si+ ion irradiation of α-Ga2O3 at doses of 8·1012 cm-2, 8·1014 cm-2, and energy of 100 keV on the gas-sensitive properties has been studied. It is shown that irradiation of α-Ga2O3 layer grown by halide vapor phase epitaxy with implanted Si+ ions allows effective control of its sensitivity to H2, response, and recovery times, as well as varying the operating temperatures. The maximum sensitivity to H2 occurred for samples with Si+ ion...

Laser-induced photoacoustic characterization on thermal diffusivity of chitosan and sago starch biocomposite blend films

C.K. Sheng, W.M.M. Yunus, W.Md.Z.W. Yunus & M.Z.Ab. Rahman
The photoacoustic(PA) technique has been testified to be versatile and also reliable for measuring the thermal properties of most materials. For example, it has been utilized to verify the thermal diffusivity of semiconductors, polymers, superconductor, metal and glass. In this study, the thermal diffusivity of the sago starch and chitosan polymer blend films was characterized using the laser-induced photoacoustic technique. It is based upon the theoretical analysis on the measured photoacoustic signal as a function...


Anton Pogrebnoi
Fused Deposition Modeling method (FDM) is widely used in various fields of science for prototyping and manufacturing of final functional parts. The actual problem of the FDM method is the low bond strength between the layers of printed parts. Proposed 3D-printing method is based on the formation of double-layer weave between polymer threads. An unfilled polylactide (PLA) was used for fabrication of samples to demonstrate the proposed method. PLA samples with double-layer weave obtained by...

Registration Year

  • 2022

Resource Types

  • Text
  • Journal Article


  • Peter the Great St. Petersburg Polytechnic University
  • Ioffe Institute
  • Institute of Macromolecular Compounds
  • National Defence University of Malaysia
  • Universiti Malaysia Terengganu
  • Universiti Putra Malaysia
  • Institute of Problems of Mechanical Engineering
  • Kalasalingam Academy of Research and Education
  • ITMO University
  • Perm National Research Polytechnic University