https://www.elibrary.ru/title_about_new.asp?i 1605-8119 Materials physics and mechanics 17 2 2013 1-90
RAR RUS 93-110 Kurukshetra University Sharma
Kurukshetra, India
 Ecole polytechnique fédérale de Lausanne (EPFL) Sharma
Lausanne, Switzerland
 IIT Roorkee Bhargava
India
 Wave motion and representation of fundamental solution in electro-microstretch viscoelastic solids The homogeneous isotropic electro.microstretch viscoelastic solids have been taken into consideration for investigating the propagation of plane waves and fundamental solution. For two dimensional model, it is found that there exists two coupled longitudinal waves namely longitudinal displacement (LD) wave and longitudinal microstretch (LM) wave and two coupled transverse displacement and transverse microrotational waves (CD-I and CD-II). The phase velocities, attenuation coefficients, specific loss, penetration depth are computed numerically. The resulting quantities are depicted graphically to show the viscous effect. In addition, we construct the fundamental solution of the system of differential equations in the theory of an electro-microstretch viscoelastic solids in case of steady oscillations in terms of elementary functions. Some basic properties of the fundamental solution are established. Some special cases are also discussed. elecrtro-microstretch; plane waves; phase velocity; attenuation coefficients; specific loss; penetration depth;steady oscillations; fundamental solution https://mpm.spbstu.ru/article/2013.29.1/ MPM_2013_17_2_P01.pdf
RAR RUS 111-120 Ioffe Institute Vinogradova
St.Petersburg, Russia
 ITMO University Lipnitskaya
St.Petersburg, Russia
 Ioffe Institute Mynbaev
St.Petersburg, Russia
 ITMO University V.E. Bougrov
St.Petersburg, Russia
 ITMO University Kovsh
St.Petersburg, Russia
 Peter the Great St. Petersburg Polytechnic University Odnoblyudov
St.Petersburg, Russia
 Ioffe Institute Nikolaev
St.Petersburg, Russia
 F-1445-2014 7202768874 0000-0003-3738-408X ITMO University Romanov Alexey alexey.romanov@niuitmo.ru
St.Petersburg, Russia
 Optimization of light extraction from power LED chip-on-board modules emitting in ultraviolet range of spectrum This article investigates the problem of light extraction from LED devices fabricated via chip-on-board technology and emitting in ultraviolet (UV) range (360-380 nm) of spectrum. The measurements of electrical and optical properties of devices with varying number and arrangement of semiconductor chips were conducted. Optimization modeling was performed with Zemax software. Modeling included the choice of substrate material, variation in the chip arrangement, and the change in the properties of the covering layer. All together, the accomplished study allowed us to elaborate the recommendations for improving the performance of UV LED devices. In particular, it was demonstrated that the optimization of chip arrangement on the substrate can provide 10 % increase in energy efficiency of LED modules. ultraviolet LED; chip-on-board; energy efficiency https://mpm.spbstu.ru/article/2013.29.2/ MPM_2013_17_2_P02.pdf
RAR RUS 121-134 Karunya University Selvamani
India
 Government Arts College (Autonomous) Ponnusamy
India
 Flexural vibration in a heat conducting cylindrical panel resting on Winkler elastic foundation Flexural vibration in a homogeneous isotropic heat conducting cylindrical panel resting on the elastic medium (Winkler model) is investigated in the context of Coupled theory of thermoelasticity (CT) and Lord-Shulman (LS) generalized theory of thermoelasticity. The analysis is carried out by introducing three displacement potential functions so that the equations of motion are uncoupled and simplified. A modified Bessel function solution with complex arguments is then directly used for the case of complex eigen values. In order to illustrate theoretical development, numerical solutions are obtained for non-dimensional frequency, attenuation coefficient (symmetric and skew symmetric) and are presented graphically for a zinc material. The numerical results indicate that the effect of thermal relaxation time and the damping of embedded medium on the non-dimensional frequency are very pronounced and also LS model is suitable for elastic material. flexural vibration; heat conducting cylindrical panel resting on elastic foundation https://mpm.spbstu.ru/article/2013.29.3/ MPM_2013_17_2_P03.pdf
RAR RUS 135-141 ITMO University Aseev
St.Petersburg, Russia
 ITMO University Kolobkova
St.Petersburg, Russia
 ITMO University Ya.A. Nekrasova
St.Petersburg, Russia
 ITMO University Nikonorov
St.Petersburg, Russia
 ITMO University Rokhmin
St.Petersburg, Russia
 Oxy-fluoride glasses for red phosphors Oxy-fluoride glasses doped with different activators have been developed and synthesized. Investigation of spectral and luminescent properties of the oxy-fluoride glasses have been carried out. The prospects of applications of the glasses as a red phosphor for white light emitted diodes have been discussed. oxy-fluoride glasses; red phosphor https://mpm.spbstu.ru/article/2013.29.4/ MPM_2013_17_2_P04.pdf
RAR RUS 135-141 59122315900 0000-0002-1572-2108 Kurukshetra University Kumar Rajneesh
Kurukshetra, India
 Chaudhary Devilal University Meglani
Haryana, India
Deenbandhu Chhotu Ram University Garg
Murthal (Sonipat), India
Influence of imperfect interface on reflection and transmission coefficients of plane waves between two different fluid saturated porous half spaces The present study is concerned with the reflection and transmission of plane waves at an imperfect interface between two different fluid saturated porous half spaces. The expression for the reflection and transmission coefficients which are the ratios of the amplitude of reflected and transmitted waves to the amplitude of incident waves are obtained for an imperfect boundary and deduced for normal stiffness, transverse stiffness. The variations of amplitude ratios with angle of incidence are depicted graphically. A particular case of reflection at the free surface in fluid saturated porous half spaces has been deduced and discussed. A special case of interest has also been deduced from the present investigation. It is found that amplitude ratios of the reflected and transmitted waves are affected by the stiffness of the media. porous; amplitude ratios; reflection; transmission; normal stiffness; transverse stiffness https://mpm.spbstu.ru/article/2013.29.5/ MPM_2013_17_2_P05.pdf
RAR RUS 135-141 Sree Sastha Institute of Engineering and Technology Sagadevan
India
 Sree Sastha Institute of Engineering and Technology Varatharajan
India
 Spectral and dielectric properties of Triglycine barium dichloride dihydrate NLO single crystal Single crystals of Triglycine barium dichloride dihydrate were grown by slow evaporation technique. The unit cell dimensions and space group of the grown crystals were confirmed by single crystal X-ray diffraction. The functional groups present in the structure of the grown crystal are identified by using FTIR spectral analysis. The microhardness study shows that the Vickers hardness number of the crystal increases with the increase in applied load. Dielectric constant and dielectric loss measurements were carried out for different temperatures and frequencies. single X-ray diffraction; FTIR; UV; microhardness and dielectric studies https://mpm.spbstu.ru/article/2013.29.6/ MPM_2013_17_2_P06.pdf
RAR RUS 158-163 Karunya University Selvamani
India
 Government Arts College (Autonomous) Ponnusamy
India
 Elasto dynamic wave propagation in a transversely isotropic piezoelectric circular plate immersed in fluid The elasto dynamic wave propagation in a piezoelectric plate immersed in fluid is studied based on the three dimensional theory of linear elasticity. Three displacement potential functions are used to uncouple the equations of motion in radial, circumferential and axial directions. The frequency equations that include the interaction between the plate and fluid are obtained by the perfect-slip boundary conditions using the Bessel function solutions. The numerical calculations are carried out for the material PZT-4 and the computed nondimensional frequency, phase velocity and attenuation coefficient are plotted as the dispersion curves for the immersed plate with different velocity ratio. olid-fluid interface; wave propagation; vibration of doubly connected plate; plate immersed in fluid; sensors; actuators https://mpm.spbstu.ru/article/2013.29.7/ MPM_2013_17_2_P07.pdf
RAR RUS 178-182 ITMO University Ivukin
St.Petersburg, Russia
 ITMO University V.E. Bougrov
St.Petersburg, Russia
 ITMO University Kovsh
St.Petersburg, Russia
 Peter the Great St. Petersburg Polytechnic University Odnoblyudov
St.Petersburg, Russia
 National Research University Higher School of Economics Shalkovskiy
Moscow, Russia
 F-1445-2014 7202768874 0000-0003-3738-408X ITMO University Romanov Alexey alexey.romanov@niuitmo.ru
St.Petersburg, Russia
 Heat transfer simulation and retrofit LED lamp plastic heat sink material optimization Aims of this work were research of the material transfer properties influence on heat transfer and subsequent search of the heat dissipation optimization ways. Subject of the research was plastic heat sinks for retrofit LED lamps. To achieve this aims numerical simulations of free convection flow were performed which were coupled with simulation inside solid parts of the heat sink. In this study, parametrical researches took place. During this study, heat transport properties of the heat sink material were varied. Derived results allowed to make conclusion about optimal heat transport properties of the plastics which can be used in retrofit LED lamp production. In addition, some heat sink structure improvements were proposed. heat transfer; heat conducting plastics; retrofit LED lamp https://mpm.spbstu.ru/article/2013.29.8/ MPM_2013_17_2_P08.pdf