Additive model of Larix sp. forest stand biomass sensitive to temperature and precipitation variables in Eurasia

The first attempt of modeling changes in additive component composition of biomass of Larix sp. communities on the Trans-Eurasian hydrothermal gradients based on regional peculiarities of age and morphology of the forests is attempted. The increase of all biomass components of the tree layer with increasing temperature at the constant precipitation and its decrease with increasing precipitation at the constant temperature is established. The positive relationship of the understory biomass with the temperature in the areas of insufficient moisture as the transition to moisture-rich areas is replaced by the opposite one. The development of such models for basic forest-forming species in Eurasia will give possibility to predict any changes in the biological productivity of forest cover of Eurasia in relation to climate change. © 2019 IOP Publishing Ltd. All rights reserved

The issues of weed infestation with environmentally hazardous plants and methods of their control

The authors analyze expansion of segetal and ruderal vegetation on agricultural lands in Leningrad and Tomsk oblasts, typical for the European and Asian parts of Russia. The spreading conditions, composition of species, biological features and ecological requirements of the most aggressive species are identified. Some effective ways of weed control are suggested

What is a possible response of forest biomass to changes in Eurasian air temperature and precipitation? A special case for the genus Betula spp

Forest ecosystems, as sinks of atmospheric carbon, play an important role in reducing greenhouse gas release and preventing air temperatures from rising. Simultaneously, climate change entails changes in forest cover. We describe the change of Betula spp. stand biomass (tha-1) along the trans-Eurasian gradients of rainfall and temperature using the harvest data from 650 forest stands and climate data. Birch stand biomass increased with growing rainfall within the evaluated range from 200 to 800 mm per year, as well as with increasing the mean winter temperature from -40 C to + 10 C regardless of the rainfall level. The comparison of our results for birches with analogous results for coniferous species shows that forest responses to changes in climate indices are species-specific. © Published under licence by IOP Publishing Ltd

Allometric models of Picea spp. biomass for airborne laser sensing as related to climate variables

Over the past two decades, active airborne laser sensing technology has been intensively used to scan the forest cover, providing such morphometric indicators of trees as the width and projection area of the crown, the height of the tree. The author's database of harvest data of 1550 model trees of genus Picea spp. of Eurasia is used in the work. Allometric models of biomass components, including the crown width, tree height, winter temperatures and precipitation as independent variables, are designed. The biomass of all components of equal-sized trees is described by the propeller-shaped 3D picture. In cold regions, when precipitation increases, the biomass decreases, but as one moves to cold regions, it is characterized by an opposite or neutral trend. As the temperature increases in humid regions, the biomass increases, but as the transition to dry conditions begins to decrease. © Published under licence by IOP Publishing Ltd

Metal degassing in vacuum-chamber of circulating vacuum degasser of JSC EVRAZ NTMK

For smelting of high-quality metal for transport purposes, it is necessary to limit the content of harmful impurities in it, including dissolved gases. For example, hydrogen content in the finished product should not exceed more than 2 ppm. In order to obtain low residual hydrogen content in steel in the converter shop of JSC EVRAZ NTMK, the transport metal is processed at circulating vacuuming plants. Circulating vacuum degasser is the last stage of steel processing before casting on continuous casting machine, so it is important to study and improve the technological processes in it. To investigate the physico-chemical processes occurring in this metallurgical unit, a hydrodynamic model of the system circulating vacuum degasser – steel ladle was created. Based on theoretical calculations and experiments conducted on a physical model, the main dependencies between the structural and technological parameters of the metallurgical unit were determined. The resulting equation makes it possible to determine the rate of metal circulation in vacuum chamber depending on gas flow rate supplied to inlet snorkel and its inner diameter at circulating vacuuming plants designed for metal processing in steel ladles with a capacity of 140 – 180 tons. Theoretical calculations were confirmed by practical smelting in a steelmaking unit. It is shown that during the wear of lining of the inlet snorkel vacuum chamber, in order to obtain stable residual hydrogen content, it is necessary to make changes in the technological process of vacuuming. Additionally, rational technological parameters of steel processing at the circulating vacuuming plant were determined on the basis of theoretical calculations. © 2022 National University of Science and Technology MISIS. All rights reserved

Metal Degassing in Vacuum-Chamber of Circulating Vacuum Degasser of JSC EVRAZ NTMK

Abstract: For smelting of high-quality metal for the applications in transport vehicles, it is necessary to limit the content of harmful impurities in it, including dissolved gases. For example, hydrogen content in the finished product should not exceed more than 2 ppm. In order to obtain low residual hydrogen content in steel in the converter shop of JSC EVRAZ NTMK, the transport metal is processed at circulating vacuuming plants. Circulating vacuum degasser is the last stage of steel processing before casting on continuous casting machine, so it is important to study and improve the technological processes in it. To investigate the physico-chemical processes occurring in this metallurgical unit, a hydrodynamic model was created for the system that includes the circulating vacuum degasser and the steel ladle. Based on theoretical calculations using physical model and experiments conducted, the main dependencies between the structural and technological parameters of the metallurgical unit were determined. The resulting equation makes it possible to determine the rate of metal circulation in vacuum chamber depending on the gas flow rate supplied to inlet snorkel and its inner diameter at circulating vacuuming plants designed for metal processing in steel ladles with a capacity of 140–180 tons. Theoretical calculations were confirmed by practical smelting in a steelmaking unit. It is shown that in order to obtain stable residual hydrogen content during the wear of lining of the inlet snorkel vacuum chamber, it is necessary to make changes in the technological process of vacuuming. Additionally, rational technological parameters of steel processing at the circulating vacuuming plant were determined on the basis of theoretical calculations. © 2022, Allerton Press, Inc

Chemical composition of clinopyroxenes and melt inclusions in clinopyroxenes from rocks of the Malaita Island, Ontong Java Plateau (Pacific Ocean)

The paper is based on new results of melt inclusion studies in minerals. Physicochemical and geochemical parameters of plateau basalt magmatic systems of the Siberian Platform and Ontong Java Plateau (Pacific Ocean) have been established. The studied melts are enriched in Fe. That differs them from magmatic melts of mid-ocean ridges (MOR). A comparative analysis of data on inclusions has shown a similarity of continental and oceanic plateau basalt magmatic systems. They considerably differ from those of MOR and intraplate oceanic islands. Crystallization of oceanic plateau basalts took place at lower temperatures and pressures as compared with similar rocks of the Siberian Platform. The data on inclusions evidence that the melts of the Siberian Platform and the Malaita Island underwent a serious evolution in contrast to magmas of the Nauru Basin that have more stable geochemical parameters. The most fractionated low-temperature high-Fe magmas with elevated contents of trace and rare-earth elements occur in the Malaita Island (Ontong Java Plateau) magmatic system