• Journal of Welding and Joining
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• v.12 no.2
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• pp.87-96
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• 1994

Correlation between microstructural features and segregation of elements (Si, Mn, P and S) near the mid of thickness in the base metal and the synthetic HAZ was investigated. Furthermore, the relationship between the degree of center segregation and weld cold cracking susceptibility in the thickness direction was also conducted by evaluating the effect of P concentration on the critical applied stress. The results obtained are as follows: 1) Pearlite band, containing the MnS type inclusion and a locally transformed structure with a higher hardness, was observed in the center segregation region. 2) By the weld thermal cycle, center segregation region was transformed to the white band which had a higher hardness than that of base metal due to a greater hardenability of concentrated Mn, P etc.. 3) Weld cold cracking susceptibility in the thickness direction was mainly dependent on the concentration of impurity elements rather than on the number of the segregated particles near the mid of thickness. 4) During welding, the higher concentrated region was easily changed into white band. Therefore, it could be predicted that the initiation and propagation of a cold crack would be promoted by increasing the restraint stress and hydrogen content.

• Journal of Ocean Engineering and Technology
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• v.16 no.2
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• pp.72-79
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• 2002

In this study, time-dependent distributions of temperature and stresses, in the box-column welded from ultra thick plates with center segregation, has been analyzed by the commercial finite element package SYSWELD+, for several types and angles of groove. The major points of investigation are the optimum type and angle of groove that minimize weld stress specially at the center segregation, as well as temperature distribution, residual stresses and changes in the mechanical properties. The results can be summarized as follows; 1) Generally the thermal cycle at the root of groove exhibits relatively rapid cooling pattern, however, most of the other part weldment have a slow cooling pattern in all groove types. 2) Most of the micro-structures of weldment are composed of ferrite and pearlite, meanwhile we could find martensite and bainite locally a the root of the groove. 3) Optimum groove type for high heat input welding of box-column corner is a double groove type, and the optimum angle for the groove is 30~$45^{\circ}$ that minimize deformation and weld stress at the center segregation.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.9
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• pp.922-928
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• 2009

This thesis puts forward a suggestion of measuring inner crack and center segregation in steel processing by using scanner and image processing with sulfur printer. To sum up, there are three points in this system. First, it scans sulfur printer and process the image by using histogram, image processing, and the mask. Second, it measures crack and center segregation by the fictitious image and output the length, thickness, exponent and grade on the mornitor. And finally, it gathers the measurement result image and data at the server and this information is used as data for the next casting.

• Journal of Korea Foundry Society
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• v.30 no.4
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• pp.130-136
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• 2010

Sulfide segregation behavior, characteristics of solidification microstructure and compositional distribution in the riser/castings junction of heavy-section main bearing support (MBS) steel castings were investigated; Sulfide streaks of A segregation were formed in the transitional region from columnar grain to coarse equiaxed grain and floated with aggregation of the dendritic free crystal. Solute segregation behaviors of elements Si, P and S were V shape negative segregation from the bottom of the castings to upper part of the riser with the reference of vertical center-line of the specimen block. Those of elements C and Mn were V shape negative segregation in the main body and A shape positive segregation in the riser of the casting. Just beneath the pipe shrinkage in the riser segregation ratio of each element was the highest, and that of S was 3.6 times higher, C 3.3 times, P 2.1 times, Si 1.6 times and Mn 1.0 times respectively. [Mn/S] ratio of the specimen block was distributed in the wide range of 20~275.

• Journal of Genetic Medicine
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• v.17 no.1
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• pp.51-54
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• 2020

Since the American College of Medical Genetics and Genomics and Association of Molecular Pathology published their guidelines in 2015, most interpretations of genetic tests have followed them. However, all variants have only limited evidence along 28 interpretation standards, especially de novo variants. When de novo variants, which are classified as variants of uncertain significance (VUS) due to lack of evidence, are detected, segregation in the affected family could provide an important key to clarifying the variants. Autosomal dominant polycystic kidney disease is the most common inherited kidney disorder with pathogenic variants in the PKD1 or PKD2 genes. We detected a novel in-frame deletion variant in the PKD1 gene, c.7575_7577del (p.(Cys2526del)), which was interpreted as a VUS. We analyzed this variant in a Korean family to decide for segregation. Here, we report the variant as a likely pathogenic variant based on the evidence of segregation in three affected relatives and two unaffected members.

• Journal of Welding and Joining
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• v.34 no.5
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• pp.61-69
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• 2016

A numerical simulation of the solid/liquid coexistence temperature range, using solidification segregation model linked with the Kurz-Giovanola-Trivedi model, explained the mechanism of the BTR shrinkage (with an increase in welding speed) in type 310 stainless steel welds by reduction of the solid/liquid coexistence temperature range of the weld metal due to the inhibited solidification segregation of solute elements and promoted dendrite tip supercooling attributed to rapid solidification of laser beam welding. The reason why the BTR enlarged in type 316 series stainless welds could be clarified by the enhanced solidification segregation of impurity elements (S and P), corresponding to the decrement in ${\delta}-ferrite$ crystallization amount at the solidification completion stage in the laser welds. Furthermore, the greater increase in BTR with type 316-B steel was determined to be due to a larger decrease in ${\delta}-ferrite$ amount during welding solidification than with type 316-A steel. This, in turn, greatly increases the segregation of impurities, which is responsible for the greater temperature range of solid/liquid coexistence when using type 316-B steel.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.332-334
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• 2009

This thesis puts forward a suggestion of measuring inner crack and center segregation in steel processing by using scanner and image processing with sulfur printer. This is a system to scan according to the program, to choose the size of the specimen and to press the 'Measurement' button, come to a check result, to send the result to the server, and to save the data and check the measurement result in web. To sum up, there are three points in this system.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.31.2-31.2
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• 2020

Mass segregation, a tendency of more massive galaxies being distributed closer to the cluster center, is naturally expected from dynamical friction, but its presence is still controversial. Using deep optical observations of 14 Abell clusters (KYDISC) and a set of hydrodynamic simulations (YZiCS), we find in some cases a hint of mass segregation inside the virial radius. Segregation is visible more clearly when the massive galaxy fraction is used instead of mean stellar mass. The trend is more significant in the simulations than in the observations. To find out the mechanisms working on mass segregation, we look into the evolution of individual clusters simulated. We find that the degree of mass segregation is different for different clusters: the trend is visible only for low-mass clusters. We compare the masses of galaxies and their dark haloes at the time of infall and at the present epoch to quantify the amount of tidal stripping. We then conclude that satellites that get accreted at earlier epochs, or galaxies in more massive clusters go through more tidal stripping. These effects in combination result in a correlation between the host halo mass and the degree of stellar mass segregation. This is a work submitted to The Astrophysical Journal (under review).

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.664-667
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• 2001

Segregation of binary particle systems in a horizontally gyrated bed has been experimentally studied to recover the heavy metals from municipal waste incineration (MWI) ash. Differences in density and size had less effect on segregation. Effective segregation took place under the centrifugal effect of 1 or less for any particle size ratio. Zn, Cu and Pb were concentrated in the upper side of bed by the horizontal vibration. However, there was less change in concentration for other metals such as Mg, Al and Fe etc. The separation system with the horizontal gyrating separator proved to be an effective method for the pretreatment of recovering Zn, Cu and Pb from incineration residues.

• Journal of Korea Foundry Society
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• v.25 no.6
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• pp.240-248
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• 2005

The rheocasting characteristics are strongly influenced by the microstructural morphology such as particle size, form factor and contiguity. In this study, the effect of structural morphology on fluid flow characteristics of A356 semi-solid alloy was investigated with a vacuum suction fluidity test. Semi-solid metal slurry was made by the mechanical stirring, the liquidus casting, and H-NCM to be analysed. H-NCM could obtain uniform and fine globular microstructures of 0.9 form factor and 55 ${\mu}m$ particle size. Inoculation was found to be effective for reducing particle size, however, for H-NCM it should be avoided due to the cause of increasing contiguity. The fluidity test indicated that the non-stirring method had higher fluidity and smaller liquid segregation in the same solid faction of 0.4 than the stirring method, for smaller particle size and higher form factor. It was observed that liquid segregation decreased as the particle size is smaller and form factor is higher. The results of die-casting experiment were a good agreement with those of fluidity test.