Fractionation, Characterization, and Analysis of Nano- and Microparticles in the Estimation of the Contribution of a Metallurgical Enterprise to the Pollution of Urban Dust

The metal concentrations and isotopic compositions (13C, 207/206Pb) of urban dust, topsoil, and PM10 samples were analyzed in a residential area near Donghae port, Korea, which is surrounded by various types of industrial factories and raw material stockpiled on empty land, to determine the contributions of the main pollution sources (i.e., Mn ore, Zn ore, cement, coal, coke, and topsoil). The metal concentrations of urban dust in the port and residential area were approximately 85~112 times higher (EF > 100) in comparison with the control area (EF < 2), especially the Mn and Zn ions, indicating they were mainly derived from anthropogenic source. These ions have been accumulating in urban dust for decades; furthermore, the concentration of PM10 is seven times higher than that of the control area, which means that contamination is even present. The isotopic (13C, 207/206Pb) values of the pollution sources were highly different, depending on the characteristics of each source: cement (−19.6‰, 0.8594‰), Zn ore (−24.3‰, 0.9175‰), coal (−23.6‰, 0.8369‰), coke (−27.0‰, 0.8739‰), Mn ore (−24.9‰, 0.9117‰), soil (−25.2‰, 0.7743‰). As a result of the evaluated contributions of pollution source on urban dust through the Iso-source and SIAR models using stable isotope ratios (13C, 207/206Pb), we found that the largest contribution of Mn (20.4%) and Zn (20.3%) ions are derived from industrial factories and ore stockpiles on empty land (Mn and Zn). It is suggested that there is a significant influence of dust scattered by wind from raw material stockpiles, which are stacked near ports or factories. Therefore, there is evidence to support the idea that port activities affect the air quality of residence areas in a city. Our results may indicate that metal concentrations and their stable isotope compositions can predict environmental changes and act as a powerful tool to trace the past and present pollution history in complex contexts associated with peri-urban regions.

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Estimating the Stress-Strain State of Roll by Temperature Gradient in the Course of its Heat Treatment

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.316.967 ◽

2021 ◽

Vol 316 ◽

pp. 967-972

Author(s):

Alexander S. Savinov ◽

Sergey M. Andreev ◽

Nikolay A. Feoktistov

Keyword(s):

Heat Treatment ◽

Temperature Gradient ◽

Strain State ◽

Thermal State ◽

Maximum Temperature ◽

Cast Billet ◽

Treatment Schedule ◽

Stress Strain ◽

Metallurgical Enterprise ◽

Stress Strain State

The paper considers the issue of mathematical simulating the stress-strain state of a roll in the course of its heat treatment. It is shown that a sound heat treatment schedule affects significantly the economic efficiency of a metallurgical enterprise. The mathematical apparatus is provided to estimate the thermal interaction in the casting-furnace system, based on which a program for calculating the thermal state of a roll during heat treatment has been developed. Using this program allows evaluating the thermal stresses occurring in a roll during the heat treatment cycle and reducing the risk of discontinuity in the roll cast billet. Also, using the program developed, allows significant reducing the engineer-technologist man-hours for the design of the process cycle of the casting heat treatment. An example of calculating the thermal state of a roll with a diameter of 930 mm in casting is given. The change in the dynamics of the maximum temperature gradient along the product radius is shown, while correlating it with the furnace setting.

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