Test and Analysis of TIG-MIG Hybrid Welding Are

A high-speed camera is used to observe the arc starting and arc stabilization process of the TIG-MIG hybrid welding system. Paschen’s law is used to analyze the path of TIG welding arc breakdown under the condition of the conductive channel provided by the MIG welding arc, and the arc starting process of the double arc hybrid welding is determined. The study found that when the electrode spacing is less than 8.5 mm, two molten pools can form a common molten pool after arc initiation of MIG welding; when the spacing is 10 mm, the two molten pools after arc initiation form a “8” shape; When the distance is 12 mm, there is a low temperature zone between the two arcs, which is separated.

A comprehensive study of the high temperature pyrolysis of sewage sludge: kinetics, energy analysis and products formation

<p>This study evaluates the pyrolysis of sewage sludge until 960 °C using heating rates between 3 K/min and 12 K/min in a macro TG/EGA. Mass and energy balances and kinetic parameters are determined. Thermal decomposition is divided into a low temperature zone (until 550 °C to 590 °C), for decomposition of organic matter, and a high temperature zone, for decomposition of inorganic matter and secondary reactions of the residual organic matter. In dry basis at 570 °C solid, liquid and gaseous products amount to 69.2 wt.-%, 29.2 wt.-% and 1.6 wt.-%, respectively. An increment in the final temperature to 960 °C causes a successive decrease of the solid residue to 56.9 wt.-%. The solid product contains more than 80 wt.-% mineral matter with high amounts of valuable elements, such as Ca and P. An energy requirement of 2.18 MJ/kg of dry sewage sludge is calculated for the pyrolysis until 570 °C. At this temperature, 58.5 % of the energy entering the process is concentrated in the liquid product and 40.0 % in the solid. A suitable set of kinetic parameters is determined through a formal independent parallel reactions model with six-pseudo components, using a combination of isoconversional and fitting methods.</p>

Oil as the result of lithogenesis complicated by intensification of tectonic-hydrothermal activity (on the example of Western Siberia)

The paper is meant to prove that structural reconstruction of riftogenic basins is accompanied by the intensification of tectonichydrothermal activity. It controls the mobility of gaseous-liquid hydrocarbons during their primary and lateral migration in the process of deposit formation. The intensity index of tectonic-hydrothermal activation is equal to the ratio of maximum paleotemperatures of gaseous-liquid inclusions to the paleotemperatures calculated from vitrinite reflectance values. This parameter determined in the same intervals of a geologic section reflects the level of paleothermal incongruity in the natural system. It can be used to make predictive estimates of the areas for hydrocarbon materials. The values of this parameter vary in the range of 1.5–2.5 in promising riftogenic areas with the source rocks in the temperature zone of 80–160°С due to conducive heating.

Results of calculations of soot formation in a tractor diesel engine running on biofuel

When burning fuel in a diesel internal combustion engine, soot is an undesirable product. To reduce the soot content in the exhaust gases, it is necessary to know the physical and chemical bases of the process of soot formation and soot burnout. Due to the determining role of acetylene in the formation of polycyclic aromatic hydrocarbons in rich mixtures in the low-temperature zone and the key role of acetylene in the surface growth of a particle in the high-temperature zone, it is concluded that the rate of surface growth of a particle is proportional to the concentration of acetylene in the reaction zone, which can be determined by the gas-kinetic method, numerically solving a system of differential equations for the components of the gas mixture under consideration.

On the Connection between the 2008–2009 Activation of the Koryakskii Volcano and Deep Magmatic Processes

Abstract—The last activation of the Koryakskii volcano in 2008–2009 was accompanied by intense fumarolic and seismic activity. Volcanic activity peaked in March–April 2009 when ash plume rose to a height of 5.5 km and extended laterally over more than 600 km. To understand the dynamics of the volcanic processes and to forecast the further course of the events, it is relevant to establish whether the eruption was associated with a rise of magma to beneath the volcanic edifice or caused by fracturing of the volcano’s basement and penetration of groundwater into a high temperature zone. Based on the analysis of the images from the Japanese satellite ALOS-1 using satellite radar interferometry methods, the slope displacements of the Koryakskii volcano during its last activation have been estimated for the first time. The displacements reach 25 cm and cannot be explained by the formation of a layer of volcanic ash deposits or by the slope processes. The most likely cause of the displacements should be recognized to be the intrusion of magmatic material into the volcano edifice with the formation of a fracture with its lower edge at a depth of 0.5 km above sea level, with a size of 1.0 and 2.4 km along the strike and dip, respectively, and with a dip angle from 45° to 60°. Therefore, the processes taking place beneath the volcano can be threatening to the nearby localities and infrastructure and require continuous monitoring.

Focusing of Brownian Particles in a Fluid Induced by the Temperature Difference

In this work the Brownian motion of particles in a two-dimensional channel was numerically studied through a fluctuating-lattice Boltzmann method. The effects of the fluid temperature difference on the biased Brownian motion of particles were examined. It is shown that the particles are likely to move towards and stay at the low temperature zone. More importantly, the focusing of Brownian particles may be realized if the temperature difference is large enough. This paper also provides a quantitative analysis on this issue.