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On the basis of the previously tested model of sputtering binary layered inhomogeneous targets with light ions, a method for calculating the component composition of the surface layers of titanium carbide under stationary (stoichiometric) sputtering with light ions is proposed. The results of calculations of the component composition of the altered surface layer of titanium carbide are given in comparison with experimental data and the results of computer simulation. The proposed method for calculating the component composition based on the model of sputtering binary layered inhomogeneous targets made it possible to estimate the thickness of the changed surface layer. The proposed calculation method allows developing a technology for creating titanium carbide surfaces with a given ratio of components. [ABSTRACT FROM AUTHOR]

The paper investigates the dependence of the sputtering yields by light ions bombardment of the surface layers of titanium and tungsten, modified with carbon, on the thickness of the layer. The theoretical study was conducted on the basis of a sputtering model (previously adapted to describe the sputtering of two-component targets and layered-inhomogeneous surfaces), based on two sputtering mechanisms, which allows to analyze the obtained dependencies. Theoretical calculations of the total yields sputtering by helium ions bombardment of the surface layers of titanium and tungsten modified with carbon are given in comparison with the results of computer simulation obtained using the SRIM-2013pro program. [ABSTRACT FROM AUTHOR]

A brief review is presented of studies in the field of heat-transfer enhancement and for increasing the critical heat fluxes (CHFs) during boiling and evaporation in thin horizontal liquid layers. The effect of the liquid layer height on heat-transfer efficiency at various heat fluxes has been analyzed. Decreasing the film thickness enhances heat transfer at low heat fluxes, while heat-transfer augmentation occurs at high heat fluxes in films whose height is greater than the capillary constant. The heat-transfer coefficient (HTC) first rises with a layer height, and then decreases to pool boiling values. The structures formed in thin liquid layers are examined in a wide range of layer heights and pressures. The mechanisms of formation of various structures and the effect on heat-transfer enhancement depending on process conditions were also discussed. The existence of regimes with heat-transfer enhancement during evaporation of a liquid layer at reduced pressures has been demonstrated. The heat-transfer coefficient in these regimes is higher than during nucleate boiling in a layer of the same height at a higher pressure. This is caused by the effect of the structures formed in these regimes. It has been found that CHF rises with an increase in the layer thickness to pool boiling values. The heat-transfer coefficients during nucleate boiling in thin films on capillary-porous surfaces are approximately three to five times higher than on a smooth surface. It has been demonstrated that there is an optimal film surface at low pressures, which provides higher heat-transfer coefficients than those on a smooth surface. Higher heat conductivity coatings of the same shape considerably increase CHFs in the entire pressure range for liquid layer thicknesses of the order of the capillary constant. It was found that, with a characteristic spacing between the coating fins, which is equal to the capillary constant of the liquid, the highest heat-transfer coefficients are attained in the experiments. [ABSTRACT FROM AUTHOR]

The wetting dynamics of modified capillary-porous surfaces made of aluminum and titanium was experimentally studied at free-convective heat exchange with the environment. The influence of the concentration of ethyl alcohol and its initial temperature on the wetting front velocity has been established. The volume concentration of alcohol in the mixture varied from 0 to 95.5 %. The characteristic modes of changes in the height of the liquid rise over capillary-porous surfaces over time have been expressed in the form of power dependences. [ABSTRACT FROM AUTHOR]

The anthracite granules were coated with iron oxide by a solution combustion synthesis method in a muffle furnace oven. As for iron precursor, an iron-containing precipitate of water treatment plants was used. The influence of four different reducing reagents on surface phase composition and properties of the modified materials was investigated. Obtained samples were investigated using different diffraction and spectroscopic methods. Using the solution combustion synthesis method, anthracite granules formed fine dispersed and crystalline structures of iron oxides on their surface with the iron content up to 40.7 wt%. This had a positive effect on the catalytic capacity of the material for deironing of underground water as well as for the increase in specific surface area. The catalytic properties of the obtained samples and the effectiveness of deferrization of groundwater were investigated. The use of tested materials makes it possible to reduce of catalytic layer height of the filter media from 50 to 20 cm for the filtration rate 12 m/h and enhance the treatment efficiency during the first start-up of filters after regeneration up to 3 times. [ABSTRACT FROM AUTHOR]

In this work, a photobioreactor with microalgae biofilm was proposed to enhance CO2 biofixation and protein production using nickel foam with the modified surface as the carrier for immobilizing microalgae cells. The results demonstrated that, compared with microalgae suspension, microalgae biofilm lowered mass transfer resistance and promoted mass transfer efficiency of CO2 from the bubbles into the immobilized microalgae cells, enhancing CO2 biofixation and protein production. Moreover, parametric studies on the performance of the photobioreactor with microalgae biofilm were also conducted. The results showed that the photobioreactor with microalgae biofilm yielded a good performance with the CO2 biofixation rate of 4465.6 µmol m−3 s−1, the protein concentration of effluent liquid of 0.892 g L−1, and the protein synthesis rate of 43.11 g m−3 h−1. This work will be conducive to the optimization design of microalgae culture system for improving the performance of the photobioreactor. [ABSTRACT FROM AUTHOR]

The processes of electrodeposition of Ge and Ge-In from ammonia-tartrate solutions have been studied. The nature of interactions in thin-film systems obtained by germanium and indium codeposition has been investigated by means of potentiodynamic voltammetry in the inversion mode. The role of electrodesurface modification has been emphasized for deposition of a germanium film of a preset thickness from aqueous solutions. As was shown by the atomic force microscopy study, glossy films with a nanocrystalline structure had been formed. It has been established that, to develop silicon-germanium technologies, deposition of thin films must be performed from ionic liquids. [ABSTRACT FROM AUTHOR]

The structure of the low-alloy steel after plasma electrolytic nitriding (PEN) in electrolyte containing ammonium nitrate was investigated. The cross-sectional microstructure, composition, and phase constituents of modified layer under different processing conditions were characterized. It is shown that anode PEN provides the saturation of steel with nitrogen and formation of α-FeO, FeO, and FeO oxides, FeN nitride, and martensite. The aqueous solution that contained 15 wt.% NHCl and 5 wt.% NHNO allows one to obtain the hardened layer with a thickness of 80 μm and a microhardness up to 740 HV during 5 min at 850 °C. Surface roughness decreases from 1.5 to 0.8 μm after 5-min PEN at 650 °C. The proposed electrolyte and processing mode (750 °C, 10 min) enable to obtain the decrease in the weight loss after lubricate wear testing by a factor of 2.7. The base-nitrate electrolyte conditioned a decrease in the corrosion current density by a factor of 9 due to passivating effect of the oxide and nitride of iron. [ABSTRACT FROM AUTHOR]

Fine powders with a modified surface have been prepared via treatment of unbleached softwood cellulose with titanium tetrachloride solutions in hexane. Titanium and chlorine have been detected in the composition of the aglomerates adsorbed onto the powder particles surfaces. Physicochemical properties of the samples have been shown to be dependent on Ti(IV) content on the modified surface. [ABSTRACT FROM AUTHOR]

Silica gel modified with 3-aminopropyltrimethoxysilane was anchored with nicotinaldehyde to prepare a new chelating surface (or matrix). It was synthesized and characterized by elemental analysis, cross-polarization magic-angle spinning C nuclear magnetic resonance (NMR) spectroscopy, diffuse reflectance infrared Fourier-transform spectroscopy, nitrogen adsorption-desorption isotherm, Brunauer-Emmett-Teller surface area, and Barrett-Joyner-Halenda pore sizes. The new surface exhibits good chemical and thermal stability as determined by thermogravimetry curves. This new organic-inorganic material was used for preconcentration of Hg(II), Pb(II), Zn(II), and Cd(II) from water prior to their determination by inductively coupled plasma atomic emission spectrometry. The optimum pH for quantitative sorption of these metal ions is in the range of 6-8, and the sorption capacity is in range of 486-1,449 μmol/g. By batch method, 95 % extraction takes ≤30 min. All the metals could be desorbed with a solution of hydrochloric acid (6 N) without loss of the expensive ligand. Solutions of the metal ions were prepared by dissolution of the nitrate solution. [ABSTRACT FROM AUTHOR]