Mathematical Models for Estimating the Residual Life of Plates with Systems of Cracks Under the Action of Long-Term Static Loads, High Temperatures, and Hydrogen

2015 ◽  
Vol 212 (2) ◽  
pp. 121-130
Author(s):  
O. E. Andreikiv ◽  
N. V. Yavors’ka ◽  
V. Z. Kukhar
Keyword(s):  
Mathematical Models ◽  
High Temperatures ◽  
Residual Life ◽  
Static Loads

scholarly journals Shaping Microstructure and Mechanical Properties of High-Carbon Bainitic Steel in Hot-Rolling and Long-Term Low-Temperature Annealing

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 384
Author(s):  
Tomasz Dembiczak ◽  
Marcin Knapiński
Keyword(s):  
Mathematical Models ◽  
Hot Rolling ◽  
Constitutive Equations ◽  
Rolling Process ◽  
Bainitic Steel ◽  
Compression Tests ◽  
High Carbon ◽  
Bainite Steel ◽  
Dilatometric Studies

Based on the research results, coefficients in constitutive equations, describing the kinetics of dynamic, meta-dynamic, and static recrystallization in high-carbon bainitic steel during hot deformation were determined. The developed mathematical model takes into account the dependence of the changing kinetics in the structural size of the preliminary austenite grains, the value of strain, strain rate, temperature, and time. Physical simulations were carried out on rectangular specimens. Compression tests with a flat state of deformation were carried out using a Gleeble 3800. Based on dilatometric studies, coefficients were determined in constitutive equations, describing the grain growth of the austenite of high-carbon bainite steel under isothermal annealing conditions. The aim of the research was to verify the developed mathematical models in semi-industrial conditions during the hot-rolling process of high-carbon bainite steel. Analysis of the semi-industrial studies of the hot-rolling and long-term annealing process confirmed the correctness of the predicted mathematical models describing the microstructure evolution.

Dynamic Parameters of Prestressed Hanging Systems

2021 ◽  
Vol 887 ◽  
pp. 698-705
Author(s):  
N.S. Razzokov ◽  
U.S. Akhmadiyorov
Keyword(s):  
Operating Conditions ◽  
Local Damage ◽  
Dynamic Parameters ◽  
Dynamic Effects ◽  
Static Loads ◽  
Long Span ◽  
Design Basis ◽  
Operational Safety ◽  
Properties Of Materials

The dynamic parameters of long-span prestressed one and two-belt hanging roofs, for which the seismic wavelengths are commensurate with the dimensions of the structure in plan, are considered. Calculated expressions have been obtained to determine the dynamic parameters for symmetric and skew-symmetric oscillations depending on the length of seismic waves.To ensure the operational safety of unique buildings and structures, we studied the change in the structural properties of materials from unfavorable operating conditions, long-term, beyond design-basis static loads, high-intensity dynamic effects, compliance of the support contours and the possibility of local damage and from the failure of cables of the structures under study.

Physiological and morphological effects of climate change

2019 ◽  
pp. 120-133 ◽  
Author(s):  
Andrew E. McKechnie
Keyword(s):  
Climate Change ◽  
Body Mass ◽  
High Temperatures ◽  
Arid Zone ◽  
Future Research ◽  
Long Term Effects ◽  
Adaptation To Climate Change ◽  
Heat Events

The direct impacts of higher temperatures on birds are manifested over timescales ranging from minutes and hours to years and decades. Over short timescales, acute exposure to high temperatures can lead to hyperthermia or dehydration, which among arid-zone species occasionally causes catastrophic mortality events. Over intermediate timescales of days to weeks, high temperatures can have chronic sub-lethal effects via body mass loss or reduced nestling growth rates, negatively affecting sev eral fitness components. Long-term effects of warming manifested over years to decades involve declining body mass or changes in appendage size. Key directions for future research include elucidating the role of phenotypic plasticity and epigenetic processes in avian adaptation to climate change, examining the role of stress pathways in mediating responses to heat events, and understanding the consequences of higher temperatures for species that traverse hot regions while migrating.

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