Plasma Installation for TiO2 Fine Powder Production: Mathematical Simulation

The scheme of an evaporator of TiO2 powder based on a plasma torch of combined type is presented. That scheme is characterized by reducing of the equipment cost by decreasing of RF power in comparison to application of usual ICP torches. An analysis of thermo-physical processes of plasma generation as well as heating of fine TiO2 particles is presented. The results were a basis for creating of equipment for the production of fine TiO2 materials and nanostructured TiO2 materials with lower radio frequency (RF) power consumption

Mathematical modelling of the spatial network of bone implants obtained by 3D-prototyping

In this paper, the mathematical model suitable for bone implants 3D-prototyping is proposed. The composite material with the spatial configuration of reinforcement with matrix of hydroxyapatite and titanium alloys fibers is considered. An octahedral cell is chosen as an elementary volume. The distribution of reinforcing fibers is described by textural parameters. Textural parameters are integrated characteristics that summarize information on the direction of reinforcing fibers and their volume fractions. Textural parameters, properties of matrix and reinforcing fibers allow calculating effective physical and mechanical properties of the composite material. The impact of height and width of the octahedral reinforcement cells on textural parameters of the composite material is investigated in this work. The impact of radius of fibers is also analyzed. It is shown that the composite becomes quasi-isotropic under certain geometrical parameters of cell. © 2016 Author(s)

Feedbacks in Non-equilibrium Oxidative Plasma Reacting with Polyethylene

The experimental results on studies of loading effect at the action of a glow DC discharge in oxygen and air on polyethylene film are presented. At the increase in a polymer amount under a treatment the specific rates of etching and CO2, CO, H2O, H2 product formation rates are decreased. The gas temperature is changed slightly. The reduced electric field strength is increased in oxygen plasma and decreased in air plasma

Role of Charge of Micellar Worms in Modulating Structure and Rheological Properties of Their Mixtures with Nonionic Polymer

The paper describes phase behavior, microstructure, and rheological properties of the mixtures of surfactant micelles of varying negative charge with nonionic hydrophilic polymer poly(vinyl alcohol) (PVA) weakly interacting with the micelles. To reduce the charge of micelles, a cationic surfactant n-octyltrimethylammonium bromide was gradually added to the anionic surfactant potassium oleate. No appreciable interactions between the micelles and polymer were revealed by NMR spectroscopy. At the same time, the system shows a broad range of compatibility, which may be due to surfactant counterions preventing the demixing. The higher the concentration of added polymer, the higher the charge density of micelles necessary to prevent macrophase separation. However, SANS data demonstrate that upon the addition of polymer the intermicellar distances decrease, which suggests that the micelles are expelled from some area filled by PVA macromolecules, indicating a local demixing. A decrease of micellar charge density induces the growth of micelles from short nonoverlapping cylinders to long entangled wormlike chains both in the presence and in the absence of polymer, which is accompanied by an increase of viscosity by up to 5 orders of magnitude. Despite very weak interactions with the micelles, PVA makes their growth in length much more pronounced and forms the entanglements with micellar chains, thereby enhancing significantly the viscoelastic properties. The effect of polymer on micellar length was attributed to polymer-surfactant microsegregation increasing the local surfactant concentration and consequently the length of micelles. These data demonstrate the effectiveness of the addition of weakly interacting polymer for the modulation of rheology of wormlike surfactant micelles, thus opening a new way for manipulating the rheological properties of viscoelastic surfactants

ИССЛЕДОВАНИЕ ПРОБЛЕМ БЕЗОПАСНОСТИ ИСПОЛЬЗОВАНИЯ КОРОТКИХ ССЫЛОК

В работе рассмотрены сферы применения коротких ссылок, указаны их преимущества и недостатки. Описаны возможные уязвимости и атаки, а также методы защиты от них. Проанализирован общий уровень безопасности использования коротких ссылок

Steam turbines produced by the Ural Turbine Works for combined-cycle plants

The most interesting and innovative solutions adopted in the projects of steam turbines for combined-cycle plants with capacities from 115 to 900 MW are pointed out. The development of some ideas and components from the first projects to subsequent ones is shown. © 2013 Pleiades Publishing, Ltd

Soft elasticity in biaxial smectic and smectic-C elastomers

Ideal (monodomain) smectic-$A$ elastomers crosslinked in the smectic-$A$ phase are simply uniaxial rubbers, provided deformations are small. From these materials smectic-$C$ elastomers are produced by a cooling through the smectic-$A$ to smectic-$C$ phase transition. At least in principle, biaxial smectic elastomers could also be produced via cooling from the smectic-$A$ to a biaxial smectic phase. These phase transitions, respectively from $D_{\infty h}$ to $C_{2h}$ and from $D_{\infty h}$ to $D_{2h}$ symmetry, spontaneously break the rotational symmetry in the smectic planes. We study the above transitions and the elasticity of the smectic-$C$ and biaxial phases in three different but related models: Landau-like phenomenological models as functions of the Cauchy--Saint-Laurent strain tensor for both the biaxial and the smectic-$C$ phases and a detailed model, including contributions from the elastic network, smectic layer compression, and smectic-$C$ tilt for the smectic-$C$ phase as a function of both strain and the $c$-director. We show that the emergent phases exhibit soft elasticity characterized by the vanishing of certain elastic moduli. We analyze in some detail the role of spontaneous symmetry breaking as the origin of soft elasticity and we discuss different manifestations of softness like the absence of restoring forces under certain shears and extensional strains.Comment: 26 pages, 6 figure