Materials physics and mechanics

RAR RUS 1-8 Karpagam University Shanmughasundaram

India

Influence of abrasive water jet machining parameters on the surface roughness of eutectic Al-Si alloy - graphite composites In this study, the influence of abrasive water jet machining (AWJM) parameters such as water pressure, standoff distance, and traverse speed each at three different levels were analyzed on the surface roughness of the Al- graphite composites which are fabricated through the squeeze casting method. The experiments were conducted using L9 Taguchi technique. The percentage contribution of each process parameter on surface roughness was analyzed by means of analysis of variance. The contribution of water pressure on surface roughness was found to be more significant than traverse speed and standoff distance. Linear regression model was developed to predict the surface roughness. abrasive water jet machining; Al- graphite composites; squeeze casting; surface roughness; Taguchi; ANOVA https://mpm.spbstu.ru/article/2014.32.1/ MPM119_01_shanmughasundaram.pdf

RAR RUS 9-19 Govt. MSSS Civil Lines Singh

India

Mata Gujri College Singh

India

Punjabi University Singh

India

Punjabi University Mudahar

India

Thind

Canada

Optical characterization of sodium borate glasses with different glass modifiers The sodium borate glasses with fixed alkali content of 10 mole % and different modifiers have been prepared. The concentration of the modifiers (PbO, Al2O3 and fly-ash) has been kept at 5 mole % and results are compared with binary sodium borate glasses. From the optical data, the optical band gap and cutoff wavelength were calculated and structural changes induced by addition of these modifiers have been investigated by UV-VIS, FTIR spectroscopy, XRD and density measurements. This work can lead to future utilization of fly-ash in glass forming materials. glass; fly-ash spectroscopy density https://mpm.spbstu.ru/article/2014.32.2/ MPM119_02_singh.pdf

RAR RUS 16-24 St.-Petersburg State University Kazarinov

St.Petersburg, Russia

Institute for Problems of Mechanical Engineering of the RAS Bratov

St.Petersburg, Russia

K-4577-2013 57384230400 St.Petersburg State University Petrov Yuri y.v.petrov@spbu.ru

St.Petersburg, Russia

St.-Petersburg State University Fedorovsky

St.Petersburg, Russia

Evaluation of fracture incubation time from quasistatic tensile strength experiment Incubation time being the main characteristic parameter for dynamic fracture process is experimentally measured for PMMA utilizing optical methods. The specimen is quasistatically loaded in standard tensile testing machine until brittle fracture occurs when the sample is split into two parts. Normally this splitting of brittle materials is accompanied by the impact unloading of the sample. In considered tests tensioned samples were dynamically unloaded by stress drop wave, generated by fracture process and registered by photoelasticity technique at a certain distance from breaking line. The same experiment is simulated using ANSYS FEM software package and the incubation time is evaluated numerically. The simulation results are in a good coincidence with experimental measurements, proving the applicability of the proposed simple method for brittle fracture incubation time measurements. dynamic fracture process; fracture incubation time; quasistatic tensile strength experiment https://mpm.spbstu.ru/article/2014.32.3/ MPM119_03_kazarinov.pdf

RAR RUS 25-38 Bhilai Institute of Technology Tiwari

India

Govt. Vishwanath Yadav Tamaskar Post Graduate Autonomous College V. Dubey

India

Rani Durgawati University Chandra

India

Exact model for the elastico mechanoluminescence of II-VI phosphorst The mechanoluminescence (ML) emission during the elastic deformation of II-VI crystals occurs either due to the electrostatic interaction between dislocation segments and filled electron traps or due to the piezoelectrically-induced electron detrapping. According to electrostatic interaction model, bending of dislocation segments causes electron from the electron traps tunnel to the conduction band. The recombination of electron-hole emit energy which is absorbed by the Mn2+ centers and the subsequent de-excitation gives rise to the light emission and according to piezoelectrically-induced electron detrapping the local piezoelectric field near the detect centers reduces the trap-depth, and therefore, the detrapping of filled electron traps takes place, and subsequently the energy released non-radiatively during the electron-hole recombination excites the Mn2+ centers and de-excitation gives rise to the ML. The present paper reports that piezoelectrically-induced electron detrapping model is more suitable to explain the elastico ML of II-VI phosphors. mechanoluminescence triboluminescence II-VI crystals charged dislocations piezoelectricity https://mpm.spbstu.ru/article/2014.32.4/ MPM119_04_dubey.pdf

RAR RUS 39-50 Alexandria University Ezzat

Alexandria, Egypt

Alexandria University Youssef

Alexandria, Egypt

Thermoelectric figure-of-merit effects on fluid flow This work is related to flow of an electro conducting fluid presented thermoelectric figure-of-merit effect, in the presence of magnetic field. The electro conducting thermofluid equation heat transfer with one relaxation time is derived. The flow of electro conducting fluid over a suddenly moved plate is considered. The governing coupled equations in the frame of the boundary layer model are applied to Stokes' first problem with heat sources. Laplace transforms and Fourier transforms techniques are used to get the solution. The inverses of Fourier transforms are obtained analytically. Laplace transforms are obtained using the complex inversion formula of the transform together with Fourier expansion techniques. Numerical results for the temperature distribution and the velocity component are represented graphically. Thermoelectric figure-of-merit effect on the fluid flow is studied. electro conducting fluid flow; thermoelectric figure-of-merit effect; magnetic field https://mpm.spbstu.ru/article/2014.32.5/ MPM119_05_ezzat.pdf

RAR RUS 51-67 Karunya University Selvamani

India

Flexural wave motion in a heat conducting doubly connected thermo-elastic plate of polygonal cross-sections Flexural wave motion in a heat conducting thermo elastic doubly connected polygonal plate is studied by using the Fourier expansion collocation method. The equations of motion based on two-dimensional theory of elasticity is applied under the plane strain assumption of generalized thermo elastic plate of polygonal cross-sections composed of homogeneous isotropic material. The frequency equations are obtained by satisfying the boundary conditions along the inner and outer surface of the polygonal plate. The numerical calculations are carried out for triangular, square, pentagonal and hexagonal cross sectional plates. The computed non-dimensional frequencies are compared with the Lord-Shulman (LS), Green-Lindsay (GL), coupled Theory (CT) theories of thermo-elasticity and they are presented in Tables. The dispersion curves are drawn for non-dimensional frequencies of thermally insulated and isothermal boundaries. waves in plate; vibration of thermal plate; piezoelectric plate; plate immersed in fluid; generalized thermo elastic plate; sensors; actuators; MEMS; NEMS https://mpm.spbstu.ru/article/2014.32.6/ MPM119_06_selvamani.pdf

RAR RUS 68-87 7003559440 0000-0003-2192-0386 Institute for Problems of Mechanical Engineering RAS Skiba Nikolai nikolay.skiba@gmail.com

St. Petersburg, Russia

Grain boundary mechanisms of misfit stress relaxation in nanocrystalline films and coatings An overview of theoretical models is presented which describe specific mechanisms of internal stress relaxation in nanocrystalline films and coatings. A particular attention is devoted to such mechanisms as interfacial sliding, athermal grain boundary migration and grain boundary diffusional creep. It is shown that these specific relaxation mechanisms can effectively release, in part, misfit stresses in nanocrystalline films and coatings. nanocrystalline films and coatings; relaxation mechanisms; misfit stresses; disclinations; diffusion https://mpm.spbstu.ru/article/2014.32.7/ MPM119_07_skiba.pdf

RAR RUS 88-95 Togliatti State University Abramova

Togliatti, Russia

Togliatti State University Dorogov Maksim

Togliatti, Russia

University of Tartu Vlassov

Tartu, Estonia

University of Tartu Kink

Tartu, Estonia

University of Tartu Dorogin

Tartu, Estonia

University of Tartu Lõhmus

Tartu, Estonia

F-1445-2014 7202768874 0000-0003-3738-408X ITMO University Romanov Alexey alexey.romanov@niuitmo.ru

St.Petersburg, Russia

Togliatti State University Vikarchuk

Togliatti, Russia

Nanowhisker of copper oxide: fabrication technique, structural features and mechanical properties The work presents the technique of fabrication of copper oxide CuO nanowhiskers, the results of study of heat treatment influence on CuO nanowhisker formation, the findings on the optimal annealing temperature for nanowhisker development, and the description of nanowhisker properties. The results of the analysis of the bending strength of CuO naowhiskers and a comparison with that of ZnO nanowhiskers are given. whiskers; electrodeposition; annealing; synthesis of whiskers; heat treatment https://mpm.spbstu.ru/article/2014.32.8/ MPM119_08_abramova.pdf