1,925 research outputs found
A unified hyperbolic formulation for viscous fluids and elastoplastic solids
We discuss a unified flow theory which in a single system of hyperbolic
partial differential equations (PDEs) can describe the two main branches of
continuum mechanics, fluid dynamics, and solid dynamics. The fundamental
difference from the classical continuum models, such as the Navier-Stokes for
example, is that the finite length scale of the continuum particles is not
ignored but kept in the model in order to semi-explicitly describe the essence
of any flows, that is the process of continuum particles rearrangements. To
allow the continuum particle rearrangements, we admit the deformability of
particle which is described by the distortion field. The ability of media to
flow is characterized by the strain dissipation time which is a characteristic
time necessary for a continuum particle to rearrange with one of its
neighboring particles. It is shown that the continuum particle length scale is
intimately connected with the dissipation time. The governing equations are
represented by a system of first order hyperbolic PDEs with source terms
modeling the dissipation due to particle rearrangements. Numerical examples
justifying the reliability of the proposed approach are demonstrated.Comment: 6 figure
The Dark Matter Search at KamLAND
Recent data from the DAMA/LIBRA phase-2 confirmed detection of a signal with independent Dark Matter (DM) annual modulation signature at a 12.9 Ο CL. Our attempts to verify the DAMA/LIBRA DM observation claim led to construction of underground clean rooms at the KamLAND site and specialized laboratory for production of NaI(Tl) detectors. Current status of these facilities, methods used to grow ultra-low background NaI(Tl) crystals, and radio-purity of the latest NaI(Tl) DM detector prototype are discussed
Magnetoelectric ordering of BiFeO3 from the perspective of crystal chemistry
In this paper we examine the role of crystal chemistry factors in creating
conditions for formation of magnetoelectric ordering in BiFeO3. It is generally
accepted that the main reason of the ferroelectric distortion in BiFeO3 is
concerned with a stereochemical activity of the Bi lone pair. However, the lone
pair is stereochemically active in the paraelectric orthorhombic beta-phase as
well. We demonstrate that a crucial role in emerging of phase transitions of
the metal-insulator, paraelectric-ferroelectric and magnetic disorder-order
types belongs to the change of the degree of the lone pair stereochemical
activity - its consecutive increase with the temperature decrease. Using the
structural data, we calculated the sign and strength of magnetic couplings in
BiFeO3 in the range from 945 C down to 25 C and found the couplings, which
undergo the antiferromagnetic-ferromagnetic transition with the temperature
decrease and give rise to the antiferromagnetic ordering and its delay in
regard to temperature, as compared to the ferroelectric ordering. We discuss
the reasons of emerging of the spatially modulated spin structure and its
suppression by doping with La3+.Comment: 18 pages, 5 figures, 3 table
Role of the international english language internet olympiad in developing foreign language communicative competence of medical students
The article presents the potential of the Internet Olympiad in developing foreign language communicative competence of medical students. We described organizational issues of the English Language Internet Olympiad among medical and pharmacy students. The results of the Internet Olympiad 2016 were presented. We also determined pedagogical principles of the development of such educational project.Π ΡΡΠ°ΡΡΠ΅ ΡΠ°ΡΡΠΌΠΎΡΡΠ΅Π½ ΠΏΠΎΡΠ΅Π½ΡΠΈΠ°Π» ΠΈΠ½ΡΠ΅ΡΠ½Π΅Ρ-ΠΎΠ»ΠΈΠΌΠΏΠΈΠ°Π΄Ρ Π² ΡΠ°Π·Π²ΠΈΡΠΈΠΈ ΠΈΠ½ΠΎΡΠ·ΡΡΠ½ΠΎΠΉ ΠΊΠΎΠΌΠΌΡΠ½ΠΈΠΊΠ°ΡΠΈΠ²Π½ΠΎΠΉ ΠΊΠΎΠΌΠΏΠ΅ΡΠ΅Π½ΡΠΈΠΈ ΡΡΡΠ΄Π΅Π½ΡΠΎΠ²-ΠΌΠ΅Π΄ΠΈΠΊΠΎΠ². Π Π°ΡΡΠΌΠΎΡΡΠ΅Π½Ρ Π²ΠΎΠΏΡΠΎΡΡ ΠΎΡΠ³Π°Π½ΠΈΠ·Π°ΡΠΈΠΈ ΠΈ ΠΏΡΠΎΠ²Π΅Π΄Π΅Π½ΠΈΡ ΠΈΠ½ΡΠ΅ΡΠ½Π΅Ρ-ΠΎΠ»ΠΈΠΌΠΏΠΈΠ°Π΄Ρ ΠΏΠΎ Π°Π½Π³Π»ΠΈΠΉΡΠΊΠΎΠΌΡ ΡΠ·ΡΠΊΡ ΡΡΠ΅Π΄ΠΈ ΡΡΡΠ΄Π΅Π½ΡΠΎΠ² ΠΌΠ΅Π΄ΠΈΡΠΈΠ½ΡΠΊΠΈΡ
ΠΈ ΡΠ°ΡΠΌΠ°ΡΠ΅Π²ΡΠΈΡΠ΅ΡΠΊΠΈΡ
Π²ΡΠ·ΠΎΠ². ΠΡΠΎΠ°Π½Π°Π»ΠΈΠ·ΠΈΡΠΎΠ²Π°Π½Ρ ΠΈΡΠΎΠ³ΠΈ ΠΈΠ½ΡΠ΅ΡΠ½Π΅Ρ-ΠΎΠ»ΠΈΠΌΠΏΠΈΠ°Π΄Ρ 2016 Π³. Π’Π°ΠΊΠΆΠ΅ Π±ΡΠ»ΠΈ Π²ΡΠ΄Π΅Π»Π΅Π½Ρ ΠΏΠ΅Π΄Π°Π³ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΠΏΡΠΈΠ½ΡΠΈΠΏΡ ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΊΠΈ Π΄Π°Π½Π½ΠΎΠ³ΠΎ ΠΎΠ±ΡΠ°Π·ΠΎΠ²Π°ΡΠ΅Π»ΡΠ½ΠΎΠ³ΠΎ ΠΏΡΠΎΠ΅ΠΊΡΠ°
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