scholarly journals Development of Protective Gas Pipes Sleeves for Operation in Permafrost Soils

2021 ◽  
Vol 1079 (3) ◽  
pp. 032044
Author(s):  
P V Ksenofontov ◽  
S N Popov ◽  
Yu Yu Fedorov
2017 ◽  
Vol 110 (4) ◽  
pp. 041607 ◽  
Author(s):  
Fangze Liu ◽  
Nathan A. Moody ◽  
Kevin L. Jensen ◽  
Vitaly Pavlenko ◽  
Claudia W. Narvaez Villarrubia ◽  
...  

2015 ◽  
Vol 770 ◽  
pp. 28-33 ◽  
Author(s):  
M.A. Kuznetsov ◽  
Svetlana A. Barannikova ◽  
Evgeniy A. Zernin ◽  
A.V. Filonov ◽  
D.S. Kartcev

The effect on the deposited metal structure of nanostructured modifiers introduced into the weldpool has been studied. Methods have been developed for determining the concentration of nanostructured powders of tungsten, molybdenum and Al2O3 in protective gas and for defining their optimal concentration. The influence of nanopowders on the structure of deposited metal was examined in consumable electrode arc welding employing the austenitic steel (chemical composition: C – 0,12%, Cr – 18%, Ni – 10%,Ti – 1%) as deposit and 1.2-mm welding wire manufactured from the austenitic steel (chemical composition: C – 0,12%, Cr – 18%, Ni – 9%,Ti – 1%). Addition of nanostructured powders of tungsten, molybdenum and Al2O3 to the weldpool has shown positive effect on the structure of metal in arc welding. It is shown that introducing the powders decreases dendrite size and leads to the formation of a more equilibrium microstructure of the weld.


2015 ◽  
Vol 1128 ◽  
pp. 254-260 ◽  
Author(s):  
Radu Cristian Seculin ◽  
Barna Fazakas ◽  
Teodor Machedon Pisu ◽  
Mihai Alin Pop

The vertical MAG welding procedure is a difficult position to be executed because the trend of the molten bath flowing. This article aims to present the achievement of vertical welding joints with a linear device with a radial oscillation system that should achieve automatic vertical welds and the correlation of the welding parameters with the movement of the welding torch in order to obtain these, using the MAG procedure, protective gas M 21 (82% argon + 18% CO2), welding wire SG2, the material of the welded pieces S 355 JR. Samples will be cut from the welded steel plates and they will be characterized from the mechanical point of view (hardness, microstructure and macrostructure).


2021 ◽  
pp. 77-89
Author(s):  
I. S. Sukhachev ◽  
P. V. Chepur ◽  
A. A. Tarasenko ◽  
A. A. Gruchenkova ◽  
Yuhai Guan

The article proposes the design, design scheme and model of a vertical ground electrode system with lobe lugs for permafrost soils. The model was implemented using the ANSYS software. In the design scheme, the soil — ground electrode system is taken into account, the elastic-plastic properties of the soil are taken into account by the Drucker — Prager model. When modeling the work of the foundation soils, the Mises strength condition was adopted, according to which the equivalent stress is calculated under the condition of the material hydrostatic compression. The following boundary conditions are accepted: a cylinder-shaped soil mass is rigidly fixed along the lower face and along the side surface of the cylinder. Calculations are made for 5 standard sizes of grounding conductors. Maps of the distribution of stresses in the metal structure of the ground electrode (the rod and petals-emphasis) are received, the movements of the ground electrode in the soil mass are determined. The dependences between the maximum equivalent stresses in the ground electrode lobes and the value of vertical displacement in the ground base are established, as well as the amount of movement of the earthing pad, at which the effective equivalent voltages reach critical values in the area where the paddles are adjacent to the rod.


Author(s):  
N N Alekseev ◽  
A D Egorova ◽  
Z V Emelianova
Keyword(s):  

2020 ◽  
Vol 14 (12) ◽  
pp. 4341-4364
Author(s):  
Rupesh Subedi ◽  
Steven V. Kokelj ◽  
Stephan Gruber

Abstract. The central Slave Geological Province is situated 450–650 km from the presumed spreading centre of the Keewatin Dome of the Laurentide Ice Sheet, and it differs from the western Canadian Arctic, where recent thaw-induced landscape changes in Laurentide ice-marginal environments are already abundant. Although much of the terrain in the central Slave Geological Province is mapped as predominantly bedrock and ice-poor, glacial deposits of varying thickness occupy significant portions of the landscape in some areas, creating a mosaic of permafrost conditions. Limited evidence of ice-rich ground, a key determinant of thaw-induced landscape change, exists. Carbon and soluble cation contents in permafrost are largely unknown in the area. Twenty-four boreholes with depths up to 10 m were drilled in tundra north of Lac de Gras to address these regional gaps in knowledge and to better inform projections and generalizations at a coarser scale. Excess-ice contents of 20 %–60 %, likely remnant Laurentide basal ice, are found in upland till, suggesting that thaw subsidence of metres to more than 10 m is possible if permafrost were to thaw completely. Beneath organic terrain and in fluvially reworked sediment, aggradational ice is found. The variability in abundance of ground ice poses long-term challenges for engineering, and it makes the area susceptible to thaw-induced landscape change and mobilization of sediment, solutes and carbon several metres deep. The nature and spatial patterns of landscape changes, however, are expected to differ from ice-marginal landscapes of western Arctic Canada, for example, based on greater spatial and stratigraphic heterogeneity. Mean organic-carbon densities in the top 3 m of soil profiles near Lac de Gras are about half of those reported in circumpolar statistics; deeper deposits have densities ranging from 1.3–10.1 kg C m−3, representing a significant additional carbon pool. The concentration of total soluble cations in mineral soils is lower than at previously studied locations in the western Canadian Arctic. This study can inform permafrost investigations in other parts of the Slave Geological Province, and its data can support scenario simulations of future trajectories of permafrost thaw. Preserved Laurentide basal ice can support new ways of studying processes and phenomena at the base of an ice sheet.


2015 ◽  
pp. 99-104 ◽  
Author(s):  
N. L. Mamaeva ◽  
S. A. Petrov

A research and comparison of natural and damaged (due to the active development of oil and gas fields) permafrost soils in the Jamalo-Nenets Autonomous Okrug were carried out. The analysis was run of correlation between an average monthly temperature of air, an average monthly sum of precipitation, the weight humidity and the thickness of the seasonal thawed layer. The conclusions were drawn about a poor resistance of landscapes on the permafrost rocks to the anthropogenic interventions, which in its turn is accompanied by the cryogenic processes and unfavorable influences on the Extreme North biosphere.


Cryobiology ◽  
2010 ◽  
Vol 61 (3) ◽  
pp. 365
Author(s):  
E.S. Khlebnyy ◽  
B.I. Ivanov ◽  
B.M. Kerschengolts ◽  
A.N. Zhuravskaja ◽  
M.M. Shashurin

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