Explore the vast range of titles available.

In this study the laser-induced incandescence (LII) diagnostics has been applied for sizing of carbon-encapsulated iron nanoparticles (CEINs). The carbon covered iron nanoparticles were synthesized by shock waves pyrolysis of the mixtures of Fe(CO)5 with C2H2 or C6H6 diluted with argon. Iron nanoparticles were formed in the shock tube behind incident shock waves at the temperatures of 700-1000 K. The pyrolysis of hydrocarbons behind reflected shock waves at the temperatures of 1400-2000 K resulted in formation of carbon shell over iron nanoparticles. At the end of the CEINs formation process, particles were heated by one pulse of Nd:YAG laser operated at wavelength 1064 nm with fluences varied in the range 70- 800 mJ/cm2 to collect LII signals. The LII model, which had been used previously for iron and carbon nanoparticles separately, was updated for carbon-encapsulated iron nanoparticles. Additionally, the nanoparticle samples were investigated by a transmission electron microscope (TEM). The iron core size and carbon shell thickness were measured by statistical treatment of microphotographs. The comparison of TEM and LII particle sizing results is discussed.

The experimental investigation of iron-carbon nanoparticles synthesis by joint laser photolysis of iron pentacarbonyl in the mixture with methane or acetylene has been carried out. The radiation source used for photo-dissociation of precursors was a pulsed Nd:Yag laser operated at a wavelength of 266 nm. Under uv radiation the molecules of Fe(CO)5 decomposed, forming atomic iron vapor and unsaturated carbonyls at well-known and readily controllable parameters. The subsequent condensation of supersaturated metal vapor resulted in small iron clusters and nanoparticles formation. It was assumed that the active catalytic surface of metal nanoparticles could activate the hydrocarbon molecules up to carbon layer formation on their surface. The growth process of the nanoparticles was observed by a method of laser light extinction. Additionally nanoparticle samples were investigated by a transmission electron microscope. The particle sizes were measured by microphotographs treatment. The sizes of synthesized particles from methane-iron-pentacarbonyl mixture were found to be in a range of 4-16 nm with a count median diameter of 8.9 nm and standard deviation of 1.13. These particles consisted of iron oxide without any carbon content. The particles formed in photolysis of acetylene-iron-pentacarbonyl mixture had the sizes of 3-7 nm with count median diameter of 4 nm and standard deviation of 1.28 and contained the essential amount of carbon. The iron cores were surrounded with a carbon shell.

The structure formation in 26X1MΦA steel as a result of double quenching (the second time from the intercritical temperature range A c 1 - A c 2 ) and high tempering is established. By EBSD, the crystallographic features of the ferritic-martensitic structure formed in single and double quenching and stabilized on tempering are studied. The prospects for improving the mechanical properties of low-alloy, low-carbon Cr-Mo-V steel by quenching from the intercritical temperature range are considered

The influence of laser heated iron and carbon nanoparticles on ignition of 20 vol% stoichiometric methane-oxygen mixture in argon was studied experimentally in shock tube reactor. The concentration of nanoparticles 0.3-2.0 ppm was measured by laser light extinction. The particles were heated by Nd:Yag laser pulse operated at wavelength 1064 nm. The ignition delay times were registered by increase of OH chemiluminescence and pressure rise. The temperatures of laser heated particles and their sizes were measured by laser induced incandescence technique. The significant decrease of ignition delay times were found at addition of iron particles heated by laser pulse to the combustible mixture at the temperatures less than 1400 K. Analysis performed has shown that the effect supposedly involves catalytic reactions of methane decomposition on the surface of heated particles and allowed estimating their effective activation energy.

Atomic resonance absorption spectroscopy has been used to study the yield of molybdenum atoms in the process of ultraviolet laser pulse photo-dissociation of Mo(CO)6 vapor. Molybdenum atoms in a ground state were formed by the quenching of the electronically excited Mo atoms generated during photolysis and were detected using the resonance absorption at a wavelength of 386.41 nm. The effective quenching rates were measured in the presence of various bath gases.

The high-voltage spark testing method for protective dielectric coatings is applied in almost all manufacturing areas and is governed by ISO, ASTM etc. However, they do not take into account high voltage generation (DC or AC) and its polarity, the impact of the environment and electric field inhomogeneity. A detailed analysis and modeling of the sparking process was carried out given the polarity of the applied control voltage and the design principles of creating a strongly inhomogeneous electric field in the interelectrode gap. The possibility of monitoring dielectric coatings with a thickness of 25 μm or more while reducing the control voltage without reducing the reliability of the results is shown, which is especially important when testing the continuity of paint coatings of large area objects.

Features of structural and phase transformations, and also formation of a set of properties of Cr–Mo–V pipe steels are studied. Heat treatment regimes are developed for high-strength casing pipes for corrosion resistant application. Prospects are considered for application of computer simulation of production processes in a Visual Weld 9.0 program for developing and adjusting oil and gas pipe heat treatment regimes.

The advancement of effective spatial planning to support sustainable development and inter-regional cooperation has become an issue of serious concern for regional authorities. Spatial planning research helps to identify economic clusters and analyze their changing spatial patterns, which is important for understanding regional economic space dynamics and potential inter-regional cooperation. To support decision-makers in the development of efficient plans of spatial development encompassing the identification of the best-suited territories, a combined Geographic Information System (GIS) based approach to interpret qualitatively expressed multiple socio-economic scenarios in quantitative map-based terms of graded suitability, and a formalized approach to the socio-economic evaluation of the territory is offered. Based on GIS technology coupled with integrated cellular automata decision analysis techniques, the study provides a method that performs socio-economic assessment of the study area according to the generated scenarios of regional spatial and socio-economic development. The proposed method is applied to Primorsky and Khabarovsk Krais, located in the Russian Far East. Socio-economic scenarios of spatial development initiated by investors and regional authorities were assessed and evaluated. The generated socio-economic scenarios illustrate how the unified set of spatial and socio-economic variables can be linked and used to gain insights into inter-regional socio-economic and spatial development. The application results demonstrate the advantage of the proposed method in identifying the best-suited unit areas for targeted regional development.

Transmission and reflection spectra of single-crystal germanium plates were experimentally measured in the terahertz spectral range. The optical parameters of germanium were determined at various Sb-doping levels. Saturation of the absorption index was detected with increasing wavelength in the range of 1000–3000 μm. The optical parameters of germanium correspond to the Drude-Lorentz model.