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...     

Effect of Ultraviolet Radiation and Electric Field on the Conductivity of Structures Based on α- and ε-Ga2O3

Semiconductors - The effect of ultraviolet radiation and a strong electric field on the conductivity of structures based on two types of polymorphic gallium-oxide films is studied. Both types of...     

Chloride epitaxy of β-Ga<Subscript>2</Subscript>O<Subscript>3</Subscript> layers grown on <Emphasis Type="Italic">c</Emphasis>-sapphire substrates

The method of chloride epitaxy is employed to grow β-Ga₂O₃ epitaxial layers on a c-sapphire substrate. Purified dry air is used as the source of oxygen. The layers are studied using the methods of X-ray diffraction, optical microscopy, scanning electron microscopy, transmission electron microscopy, and micro-Raman spectroscopy. It is found that the growth plane of the layers is (\(\bar 2\)01), parallel to the substrate surface. The layers consist of separate large crystalline grains of three different in-plane orientations rotated relative to each other in the growth plane by 60°. Misorientation can be caused by the different symmetry of the substrate and the epitaxial layer.     

Strengthening of Kh18N22V2T2 steel by aging at 600–750°C

Metal Science and Heat Treatment -     

Microhardness and Crack Resistance of Gallium Oxide

Technical Physics Letters - The microhardness and crack resistance of two main gallium oxide polytypes: metastable α-Ga2O3 with a corundum structure and β-Ga2O3 (high-temperature phase)...     

Effect of Ambient Humidity on the Electrical Conductivity of Polymorphic Ga2O3 Structures

Semiconductors - The effect of ambient humidity on the electrical conductivity of α-Ga2O3 and α-Ga2O3/ε-Ga2O3 is investigated. Polymorphic epitaxial Ga2O3 layers are deposited by the...     

Adaptive crawler for external hyperlinks search and acquisition

We describe a search robot (crawler) intended to collect information regarding outgoing hyperlinks from a given set of web sites related to a certain topic. The crawler’s adaptive behavior is formulated in terms of a multi-armed bandit problem. Our experiments show that the choice of an adaptive algorithm for the crawler’s rational behavior depends on the actual topic of the underlying set of web sites.     

Nanostructured Magnetic Sorbents for Selective Recovery of Uranium(VI) from Aqueous Solutions

Direct sol-gel, novel template, and additional high-temperature reduction procedures for preparing iron oxides and their composites, showing promise for selective sorption of dissolved U(VI) from aqueous media of various acidities, are described. The sorption activity of the materials was studied, the kinetic curves of the sorption were obtained, and the efficiency of the selective recovery of U(VI) from aqueous solutions with different pH values using the new sorbents was compared. The probable mechanism of the U(VI) sorption onto the sorbents studied was suggested on the basis of SEM, XPS, emf, and BET data. The quantitative sorption of U(VI) is determined to a greater extent by the composition of the sorbent solid phase, rather then by the specific surface area of the sorbents, which ranges from 0.1 to 47.3 m² g^?1 depending on the synthesis procedure. The crystalline Fe⁰ phase in the sorbents prepared using additional high-temperature reduction plays the key role in the U(VI) sorption by the reducing deposition mechanism. The saturation magnetization for this type of sorbents can reach 133–140 emu g^?1, which is an additional advantage allowing magnetic separation of the spent sorbents from the treated solutions.

     

Study of Microstructure and Mechanical Properties of Boron-Containing Hot-Rolled Steel Reinforcement

Metallurgist - Stiffened specifications for quality of reinforcement product are dictated by the contemporary market that is expressed in the introduction of new TU and GOST for manufactured...