Solar light-driven reduction of crystal violet by a composite of g-C3N4, β-Ag2Se, γ-Fe2O3 and graphite

Abstract

In this work, a new g-C₃N₄-based Z-scheme with γ-Fe₂O₃ and β-Ag₂Se both n-type semiconductors, and graphite to favor electron exchange is presented. The composite material was studied by XRD, FTIR, UV-Vis, TEM, XPS, TGA, DSC and TOF-SIMS, and the ability of this photocatalytic system to act as a photo-reductant was assessed using crystal violet (CV⁺) dye. Solar light driven photo-reduction of CV⁺ in the presence of tri-sodium citrate evidenced a synergistic enhancement of the activity of the composite toward reduction, with ～20 times higher conversion rates per unit of surface area than those of g-C₃N₄. Photo-oxidation experiments under Xe lamp irradiation in the presence of H₂O₂ also showed that the AgFeCN composite featured a higher activity (～8×) than g-C₃N₄. This Z-scheme may deserve further study as a photo-reductant to obtain hydrogen or hydrogenated compounds. Moreover, the use of CV⁺ may represent a facile procedure that can aid in the selection of new photocatalysts to be used in hydrogen production.     

Deformation of a surface layer and coating application using a flexible tool

The microstructure and properties of the functional coatings formed by impact friction processing of product surfaces with a flexible tool are studied. It is established that the processing produces a hard nanostructured surface layer with fragments up to 0.13 µm in size, as it is achieved by severe plastic deformation.     

Deep Neural Networks for Determining the Parameters of Buildings from Single-Shot Satellite Imagery

Journal of Computer and Systems Sciences International - The height of a building is a basic characteristic needed for analytical services. It can be used to evaluate the population and functional...     

Determination of the Life Cycle of Heat-Exchange Tubes of Vapor Condensers on the Basis of Statistical Analysis of Local Pitting Corrosion According to Data of Eddy Current Testing

Protection of Metals and Physical Chemistry of Surfaces - The possibility is shown of creating a chart of local corrosion damage in the walls of heat-exchange tubes on the basis of the data of...     

Preparation of highly crystalline titanium-based ceramic microfibers from polymer precursor blend by needle-less electrospinning

The aim of the present contribution is to study the influence of the post-spinning heat - treatment of single TiO₂/PVP precursor fibers on the properties and morphology of the final titanium-based microfibers. The post-spinning treatment conditions were: calcination in air at 450–600?°C and pyrolysis in argon at 1000–1700?°C. Calcination resulted in a production of anatase-rich and pure rutile fibers. The use of an alternative sintering method, the low-temperature plasma treatment, led to the crystallization of the composite Magnéli phases/polymer fibers. As a result of the same one precursor, pyrolysis at 1000?°C, the Carbon/TiO₂ composite fibers were obtained. Rising the treatment temperature in inert atmosphere led to the formation of the titanium carbide fibers. The formation process and all the obtained products were characterized by differential scanning calorimetry accompanied with thermogravimetric analysis (DSC/TGA), scanning and transmission electron microscopy (SEM, TEM), X-ray diffraction (XRD), and image analysis techniques.     

Estimation of Limit Energy Characteristics of Volumetric Pneumatic Motors Taking into Account the Process Dynamics in Working Chambers

A methodology for estimation of the limit energy characteristics of volumetric pneumatic motors based on the Parameter Space Investigation method and a generalized mathematical model in dimensionless (normalized) form taking into account the dynamics of working processes is proposed. A calculated example is presented. The methodology is applicable for determination of the limit energy characteristics of newly created design solutions, of prospects to improve the known designs of pneumatic motors, of evaluation of energy capacity of several pneumatic motors supplied from a single source of compressed air, and of the initial data preparation for parametric synthesis of rotational pneumatic drives for two or more robots taking into account their interaction.     

Cell Sheet Comprised of Mesenchymal Stromal Cells Overexpressing Stem Cell Factor Promotes Epicardium Activation and Heart Function Improvement in a Rat Model of Myocardium Infarction

Cell therapy of the post-infarcted myocardium is still far from clinical use. Poor survival of transplanted cells, insufficient regeneration, and replacement of the damaged tissue limit the potential of currently available cell-based techniques. In this study, we generated a multilayered construct from adipose-derived mesenchymal stromal cells (MSCs) modified to secrete stem cell factor, SCF. In a rat model of myocardium infarction, we show that transplantation of SCF producing cell sheet induced activation of the epicardium and promoted the accumulation of c-kit positive cells in ischemic muscle. Morphometry showed the reduction of infarct size (16%) and a left ventricle expansion index (0.12) in the treatment group compared to controls (24–28%; 0.17–0.32). The ratio of viable myocardium was more than 1.5-fold higher, reaching 49% compared to the control (28%) or unmodified cell sheet group (30%). Finally, by day 30 after myocardium infarction, SCF-producing cell sheet transplantation increased left ventricle ejection fraction from 37% in the control sham-operated group to 53%. Our results suggest that, combining the genetic modification of MSCs and their assembly into a multilayered construct, we can provide prolonged pleiotropic effects to the damaged heart, induce endogenous regenerative processes, and improve cardiac function.     

On the Electrochemical Deposition and Properties of Nickel-Based Composite Coatings

Protection of Metals and Physical Chemistry of Surfaces - Nickel-based composite electrochemical coatings (CECs) modified with graphite nitrate have been obtained. Their microstructure and...