Optimizing the Structure of a Production System for Activated Carbon

Russian Engineering Research - A system for the production of activated carbon is considered. The thermal deformation of its components in operation is of interest. A frame design is developed,...     

Chromium combustion in a nitrogen coflow

The combustion of chromium powder in a coflow of nitrogen-containing gas in a range of specific flow rate of up to 20 cm³/(s · cm²) is studied. The use of forced filtration intensifies the combustion wave propagation in the Cr–N₂ system. In this case, the combustion rate increases simultaneously with the decreasing degree of nitridation. The superadiabatic heating modes in the case of purging with pure nitrogen and a hydrogen-argon mixture are revealed. It is shown that the use of the gaseous mixture promotes the formation of the inverse combustion wave. The hardening mode implemented during forced filtration allows fixing the high-temperature single-phase nonstoichiometric nitride Cr₂N.     

Properties of silicon prepared from plant raw materials

High-purity X-ray amorphous silicon dioxide samples have been prepared by hydrolyzing siliconcontaining plants in a 0.1 N HCl solution, followed by calcination at 700°C in air. Reducing the silica with metallic magnesium, we obtained silicon, which was then purified by sequential washings with hydrochloric, hydrofluoric, and sulfuric acids and water. The fine silicon powder thus prepared, up to 97.6% in purity, ranging in color from light brown to dark brown, was characterized by X-ray diffraction and IR spectroscopy. According to total external reflection X-ray fluorescence, electron probe microanalysis, and chemical analysis data, the major impurities in the powder were silicon dioxide, iron (within 0.45%), titanium (within 0.10%), calcium (within 0.088%), and manganese (within 0.031%). According to scanning electron microscopy data, the silicon obtained has the form of spongy material ranging in pore size from 50 to 200 nm.     

Self-propagating high-temperature synthesis of ferrovanadium nitride for use in smelting high-strength low-alloy steels

A new alloying material for smelting high-strength low-alloy steel is considered: FERVANIT fused ferrovanadium nitride. Self-propagating high-temperature synthesis in the ferrovanadium-nitrogen system permits the development of a new industrial production technology for alloys based on vanadium nitride. Self-propagating high-temperature synthesis requires no electrical energy, is environmentally benign, and results in a product with good operational properties.     

Exploration of Electrochemical Reactions at Organic–Inorganic Halide Perovskite Interfaces via Machine Learning in In Situ Time‐of‐Flight Secondary Ion Mass Spectrometry

The instability of hybrid organic–inorganic perovskite (HOIP) devices is one of the significant challenges preventing commercialization. Exploring these phenomena is severely limited by the complexity of the intrinsic electrochemistry of HOIPs, the presence of multiple volatile and mobile ionic species, and the possible role of environmentally induced reactions at surfaces and triple‐phase junctions. Here, in situ studies of the electrochemistry of methylammonium lead bromide perovskite with the Au electrode interface are reported via light‐ and voltage‐dependent time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) imaging of lateral perovskite heterostructures. While ToF‐SIMS allows for the visualization of the chemical composition along the surface and its evolution with light and electrical bias, the interpretation of the multidimensional data obtained is often limited due to strong correlations between chemical signatures and the need to track multiple peaks at once. Here, a machine learning workflow combining the Hough transform and non‐negative matrix factorization and non‐negative tensor decomposition is developed to avoid this limitation and extract salient features of associated chemical changes and to separate the light‐ and voltage‐dependent dynamics. Combining these in situ characterizations and the machine learning workflow provides comprehensive information on the chemical nature of moving species, ion accumulation, and interfacial electrochemical reactions in HOIP devices.     

Self-propagating high-temperature synthesis of ferrochromium nitride

Ferrochromium nitride obtained by self-propagating high-temperature synthesis is developed as an alloying material for the production of high-purity, corrosion-resistant steel. Self-propagating high-temperature synthesis involves no energy consumption and has no environmental impact. The product has excellent properties.