Development of the Metal Rheology Model of High-temperature Deformation for Modeling by Finite Element Method

It is shown that when modeling the processes of forging and stamping, it is necessary to take into account not only the hardening of the material, but also softening, which occurs during hot processing. Otherwise, the power parameters of the deformation processes are precisely determined, which leads to the choice of more powerful equipment. Softening accounting (processes of stress relaxation) will allow to accurately determine the stress and strain state (SSS) of the workpiece, as well as the power parameters of the processes of deformation. This will expand the technological capabilities of these processes. Existing commercial software systems for modeling hot plastic deformations based on the finite element method (FEM) do not allow this. This is due to the absence in these software products of the communication model of the component deformation rates and stresses, which would take into account stress relaxation. As a result, on the basis of the Maxwell visco-elastic model, a relationship is established between deformation rates and stresses. The developed model allows to take into account the metal softening during a pause after hot deformation. The resulting mathematical model is tested by experiment on different steels at different temperatures of deformation. The process of steels softening is determined using plastometers. It is established experimentally that the model developed by 89 ... 93 % describes the rheology of the metal during hot deformation. The relationship between the components of the deformation rates and stresses is established, which allows to obtain a direct numerical solution of plastic deformation problems without FED iterative procedures, taking into account the real properties of the metal during deformation. As a result, the number of iterations and calculations has significantly decreased

EXPERIMENTAL STUDY OF TACTICAL AND TECHNICAL CHARACTERISTICS OF THE ELECTRIC DRIVE OF A STRIKEBALL WEAPON.

Electro-pneumatic actuator is an accurate external modulation of combat weapons, which is used for tactical games and development of combat skills. Electro-pneumatic drive (AEG) and its advantage in high speed of fire were investigated in the experiment and the number of its shots exceeds even the number of combat weapon's shots. The other advantages are the large number of shots on a standard battery and miniature design, because weight and size are more modulation requirement than necessity

Zel'dovich states with very small mass and charge in nonlinear electrodynamics coupled to gravity

It is shown that in non-linear electrodynamics (in particular, Born-Infeld one) in the framework of general relativity there exist "weakly singular" configurations such that (i) the proper mass M is finite in spite of divergences of the energy density, (ii) the electric charge q and Schwarzschild mass m ~ q can be made as small as one likes, (iv) all field and energy distributions are concentrated in the core region. This region has an almost zero surface area but a finite longitudinal size L=2M. Such configurations can be viewed as a new version of a classical analogue of an elementary particle.Comment: 11 pages. 1 reference added. To appear in Grav. Cosm

A Curvature Principle for the interaction between universes

We propose a Curvature Principle to describe the dynamics of interacting universes in a multi-universe scenario and show, in the context of a simplified model, how interaction drives the cosmological constant of one of the universes toward a vanishingly small value. We also conjecture on how the proposed Curvature Principle suggests a solution for the entropy paradox of a universe where the cosmological constant vanishes.Comment: Essay selected for an honorable mention by the Gravity Research Foundation, 2007. Plain latex, 8 page

Dynamical Quantum Phase Transition Without An Order Parameter

Short-time dynamics of many-body systems may exhibit non-analytical behavior of the systems' properties at particular times, thus dubbed dynamical quantum phase transition. Simulations showed that in the presence of disorder new critical times appear in the quench evolution of the Ising model. We study the physics behind these new critical times. We discuss the spectral features of the Ising model responsible for the disorder-induced phase transitions. We found the critical value of the disorder sufficient to induce the dynamical phase transition as a function of the number of spins. Most importantly, we argue that this dynamical phase transition while non-topological lacks a local order parameter.Comment: 15 pages, 6 figure

Physico-chemical characterization and anti- microbial activity of copper(II) complexes with 2-amino and 2-methylbenzimidazole derivatives

Copper(II) chloride, in warm ethanolic solution, reacted with 2-amino and 2-methylbenzimidazole derivatives to give complexes of the formula CuL2Cl2·nH2O, where L=1-benzyl-2-aminobenzimidazole 1-(4-methylbenzyl)-2-aminobenzimidazole, 1-benzyl-2-methylbenzimidazole and 1-(4-methylbenzyl)-2-methylbenzimidazole( n=1 or 2). The complexes were characterized by elemental analysis of the metal, molar conductivity magnetic susceptibility measurements and IR spectra. The molar conductivities of copper(II)complexes in dimethyl formamide (DMF) corresponding to a 1:1 type of electrolyte indicate that in all the complexes one of the coordinated chloride ions has been replaced by DMF molecule. The room temperature effective magnetic moments and IR data of the complexes suggest that all Cu(II) complexes have a tetrahedral configuration, which is realized by participation of the pyridine nitrogen of two organic ligand molecules and two chloride anions. The antimicrobial activity of the ligands and their complexes against Pseudomonas aeruginosa, Bacillus sp. Staphylococcus aureus, Sarcina lutea and Saccharomyces cerevisiae was investigated. The effect of copper complexation on the ligand antimicrobial activity is discussed

Mode-locking of incommensurate phase by quantum zero point energy in the Frenkel-Kontorova model

In this paper, it is shown that a configuration modulated system described by the Frenkel-Kontorova model can be locked at an incommensurate phase when the quantum zero point energy is taken into account. It is also found that the specific heat for an incommensurate phase shows different parameter-dependence in sliding phase and pinning phase. These findings provide a possible way for experimentalists to verify the phase transition by breaking of analyticity.Comment: 6 pages in Europhys style, 3 eps figure

Синтез, реакційна здатність та антимікробна активність заміщених тієно[2,3-d]піримідин-4(3Н)-тіо(селено)нів

A new series of R1,R2-thieno[2,3-d]pyrimidine-4(3H)-one, thione and selenone derivatives have been synthesized; the reaction of alkylation of the compounds obtained has been studied. Their structures have been confirmed by the NMR 1H and mass spectra, and elemental analysis. The antibacterial and antifungal activities in vitro against three bacterial and two fungal pathogens have been revealed using the stiff plate agar diffusion method and the serial dilution method. The minimal bactericidal, fungicidal and bacteriostatic concentrations have been obtained. The pharmacological screening has shown that some of the compounds obtained possess a good antimicrobial activity. The culture of S.aureus. appeared to be the most sensitive to compound 10a. The best fungistatic indicators against A.niger have been found for compounds 4a and 9a.Синтезирован ряд новых производных R1,R2-тиено[2,3-d]пиримидин-4(3Н)-онов, тионов и селенонов, изучена реакция алкилирования полученных соединений. Структуры полученных соединений установлены с помощью данных ЯМР 1Н и масс-спектров, а также данных элементного анализа. Антибактериальная и фунгистатическая активность in vitro против трёх видов бактерий и двух видов грибов была обнаружена с помощью метода диффузии вещества в агар и метода серийного разведения. Определены минимальные концентрации бактериальной, фунгицидной и бактериостатической активности. Фармакологическое исследование подтвердило, что некоторые из полученных продуктов проявляют хорошую антимикробную активность. Культура бактерии S.aureus наиболее чувствительна к соединению 10а. Наилучшие фунгистатические показатели против цвелевого гриба A.niger определены для соедине-ний 4а и 9а.Синтезовано ряд нових похідних R1,R2-тієно[2,3-d]піримідин-4(3Н)-онів, тіонів і селенонів та вивчено реакцію алкілування отриманих продуктів. Структури отриманих продуктів встановлені за допомогою даних ЯМР 1Н та мас-спектрів і даних елементного аналізу. Антибактеріальну і фунгістатичну активність in vitro проти 3 культур бактерій і двох видів грибів було встановлено за допомогою методу дифузії речовини в агар і методу серійних розведень. Були визначені мінімальні концентрації бактеріальної, фунгістатичної і бактеріостатичної активності. Фармакологічне дослідження підтвердило, що деякі з отриманих продуктів проявляють добру антимікробну активність. Культура бактерії S.aureus. найбільш чутлива до сполуки 10а. Найкращі фунгістатичні показники проти цвільового гриба A.niger виявлені для сполук 4а і 9а

The content and essence of education kinesiology

This work is devoted to the content and nature of educational kinesiology, its differences from the physical culture, sports kinesiology and applied kinesiolog