Investigation into the effect of low temperatures and heat treatment on the growth rate of fatigue cracks in steels

1978 ◽  
Vol 10 (6) ◽  
pp. 673-678
Author(s):  
A. V. Prokopenko
Keyword(s):  
Heat Treatment ◽  
Growth Rate ◽  
Low Temperatures ◽  
Fatigue Cracks

Effect of heat treatment on the growth rate of transverse fatigue cracks in railroad rails

1991 ◽  
Vol 27 (1) ◽  
pp. 67-69
Author(s):  
M. N. Georgier ◽  
K. P. Zamula ◽  
N. Ya. Mezhova ◽  
V. A. Reikhart
Keyword(s):  
Heat Treatment ◽  
Growth Rate ◽  
Fatigue Cracks ◽  
Railroad Rails

scholarly journals Characteristics of Black Ginseng (Panax ginseng C.A. Mayer) Production Using Ginseng Stored at Low Temperature after Harvest

Metabolites ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 98
Author(s):  
Hyo Bin Oh ◽  
Ji Won Lee ◽  
Da Eun Lee ◽  
Soo Chang Na ◽  
Da Eun Jeong ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Low Temperature ◽  
Panax Ginseng ◽  
Low Temperatures ◽  
Sugar Content ◽  
Base Material ◽  
Free Sugar ◽  
Drying Process ◽  
Heat Treated ◽  
Black Ginseng

Ginseng processing often involves multiple drying and heat treatments. Ginseng is typically processed within one week of harvesting or is stored at low temperatures to prevent spoilage. Black ginseng (BG) is manufactured by repeating the heat treatment and drying process of ginseng several times. We compared the suitability of low-temperature stored ginseng (SG) and harvested ginseng (HG) as the components for black ginseng production. SG and HG were processed into black ginseng and the appearance change, free sugar content, and benzo[a]pyrene (BAP) content were observed. Appearance observations showed the SG to be suitable in terms of quality when heat-treated at a temperature of 95 ℃ or higher. The BAP content of the SG increased significantly as the steaming process was repeated. A maximum BAP concentration of 5.31 ± 1.12 μg/kg was measured in SG steamed from 2 to 5 times, making it unsuitable for processing into BG. SG and HG showed similar trends in the content of sucrose, fructose, and glucose during steaming. This study aimed to facilitate the proper choice of base material to improve the safety of black ginseng by limiting BAP production during processing.

Study of the low cycle fatigue of 12Cr18Ni10Ti steel based on fractal analysis and artificial intelligence approaches

2021 ◽  
Vol 87 (9) ◽  
pp. 59-67
Author(s):  
A. A. Khlybov ◽  
Yu. G. Kabaldin ◽  
M. S. Anosov ◽  
D. A. Ryabov ◽  
D. A. Shatagin
Keyword(s):  
Neural Network ◽  
Growth Rate ◽  
Fractal Dimension ◽  
Low Temperatures ◽  
Main Crack ◽  
Fatigue Loading ◽  
Wide Range ◽  
Lower Temperature ◽  
Number Of Cycles ◽  
Dimension Index

The evolution of the structure and assessment of the age limit of steel 12Cr18Ni10Ti upon fatigue loading is considered using neural network modeling and approaches of fractal analysis of the microstructure. An algorithm for processing images of the microstructures has been developed to improve their quality. An indicator of the fractal dimension of the image is used as a quantitative indicator for assessing the evolution of the microstructure of the surface metal layer. A quantitative assessment of the structures at different stress amplitudes is carried out in a wide range of low temperatures using the fractal dimension index. Correlation of the fractal dimension index with the run of the sample material is shown. The appearance of the main crack was observed in the range of 0.7 - 0.8 from the number of cycles to failure, after which the crack growth rate increased. At a lower temperature, the main crack is formed later, but further loading results in a higher crack growth rate. Formation of the secondary phases in austenitic steel at a lower temperature occurred at earlier stages than that at a temperature of t = +20°C, which led to hardening of the material. An artificial neural network (ANN) has been developed and trained for assessing structural changes in metal proceeding from the fractal dimensionality of the microstructure images at different stages of fatigue loading. The developed neural network made it possible to estimate with a sufficiently high accuracy the number of cycles before damage of the sample and the residual life of the material. Thus, the developed ANN can be used to assess the current state of the material in a wide range of low temperatures.

Prediction of the fatigue strength of metals at low temperatures based on artificial intelligence

2021 ◽  
pp. 11-14
Author(s):  
Keyword(s):  
Neural Network ◽  
Artificial Intelligence ◽  
Fatigue Strength ◽  
Low Temperatures ◽  
Intelligent System ◽  
Fatigue Cracks ◽  
Test Conditions ◽  
Neural Network Prediction ◽  
Network Prediction ◽  
Trained Neural Network

An intelligent system for predicting the fatigue strength of metals in a wide temperature range is developed using a specially trained neural network. The system makes it possible to predict the number of load cycles of a part to failure, as well as the start of formation and growth rate of fatigue cracks for different test conditions, including at low temperatures. Keywords: neural network, prediction of loading cycles, low temperatures, fatigue strength. [email protected]

scholarly journals Probabilistic Evaluation of Fatigue Crack Growth Rate for Longitudinal Tungsten Inert Gas Welded Al 6013-T4 Under Various PostWeld Heat Treatment Conditions

2019 ◽  
Vol 130 ◽  
pp. 01016 ◽  
Author(s):  
I Made Wicaksana Ekaputra ◽  
Gunawan Dwi Haryadi ◽  
Stefan Mardikus ◽  
Rando Tungga Dewa
Keyword(s):  
Heat Treatment ◽  
Growth Rate ◽  
Fatigue Crack ◽  
Crack Growth Rate ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Fatigue Crack Growth Rate ◽  
Postweld Heat Treatment ◽  
Inert Gas ◽  
Probabilistic Assessment

In this study, a Monte Carlo method (MCM) was applied on the fatigue crack growth rate (FCGR) curves to evaluate a probabilistic assessment for the welded longitudinal Al 6013-T4 aluminum alloy under various post-weld heat treatment (PWHT) conditions. The welded CT specimens were manufactured by a tungsten inert gas (TIG) welding, and the fatigue crack growth (FCG) tests were conducted by following ASTM E647. Before conducting the FCG test, the PWHT conditions were applied to the welded CT specimens under three different aging times of 6 h, 18 h, and 24 h at 175 C. The FCGR curves were generated from the FCG data and plotted on the da/dN versus Δk curves. The constants C and m were determined by drawing the fitting line on the FCGR curves. A sizeable random number was generated from the obtained constants by MCM. By plotting these constants, the probabilistic assessment of FCGR was determined on the da/dN versus Δk curves. The results showed that the confidence interval was appeared on the FCGR curves and limited by the upper and lower probabilistic lines. It was found that the lower and upper probabilistic lines were formed at 1 % and 90 %, respectively.

scholarly journals Genetic and Molecular Organization of the Alkylbenzene Catabolism Operon in the Psychrotrophic Strain Pseudomonas putida 01G3

2001 ◽  
Vol 67 (1) ◽  
pp. 453-458 ◽  
Author(s):  
P. A. Chablain ◽  
A. L. Zgoda ◽  
C.-O. Sarde ◽  
N. Truffaut
Keyword(s):  
Growth Rate ◽  
Pseudomonas Putida ◽  
Low Temperatures ◽  
Multiple Alignment ◽  
Molecular Organization ◽  
Substrate Specificities ◽  
Psychrotrophic Strain ◽  
Insight Into

ABSTRACT The 11-kb sequence encompassing the alkylbenzene upper pathway inPseudomonas putida 01G3, a psychrotrophic strain able to degrade alkylbenzenes at low temperatures, was characterized. Together with a potential regulator (EbdR), six putative enzymes (EbdAaAbAcAdBC) were identified, and they exhibited highly significant similarities with enzymes implicated in the equivalent pathway in P. putida RE204. ebd genes appeared to be preferentially induced by ethylbenzene. Multiple-alignment data and growth rate measurements led us to classify 01G3 and closely related strains in two groups with distinct substrate specificities. Close to identified genes, remnants of IS5-like elements provided insight into the evolution of catabolic sequences through rearrangements from a less complex ancestral cluster.

The effect of temperature and photoperiod on larval development in Odonata

1973 ◽  
Vol 51 (11) ◽  
pp. 1165-1170 ◽  
Author(s):  
Dennis L. C. Procter
Keyword(s):  
Growth Rate ◽  
Larval Development ◽  
Low Temperatures ◽  
Development Rate ◽  
Effect Of Temperature ◽  
Enallagma Boreale

Enallagma boreale (Selys), a summer species, and Leucorrhinia glacialis (Hagen) and Libellula quadrimaculata (Linné), both spring species, were reared at various temperatures and photoperiods.E. boreale developed fastest at all temperatures, supporting my hypothesis that summer species have higher thermal coefficients for growth than spring species, but refuting my hypothesis that spring species grow faster at low temperatures.Photoperiod affected the development rate of L. glacialis and L. quadrimaculata at low temperatures, but did not affect E. boreal at any temperature, supporting my hypothesis that spring species are most likely to use photoperiod in regulating development. The striking growth-rate responses of the spring species to photoperiod at low temperatures suggest photoperiod is important in regulating development in temperate regions.

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