• Journal of Conservation Science
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• v.32 no.2
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• pp.273-291
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• 2016

Some ceramic artifacts representing time-wise from comb pattern pottery in the Neolithic Age to white porcelain in Joseon Dynasty were selected from 7 sites in the north and south area of Charyeong Mountain Range in order to making techniques interpretation and development process of ancient ceramics through physicochemical and mineralogical quantitative analysis. Studied pottery samples in the Prehistoric times showed trace of ring piling in soft-type, and pottery in the Three Kingdoms Period had both soft and hard-type but kettle-ware and storage-ware were made with ring piling, but table-ware was made by wheel spinning. Different from pottery after the Three Kingdom Period when refinement of source clay was high, pottery in the Neolithic Age and in the Bronze Age exhibited highly mineral content in sandy source clay, which showed a lot of larger temper than source clay. Groundmass of celadon and white porcelain almost did not reveal primary minerals but had high content of minerals by high temperature firing. Ceramic samples showed some different in major and minor elements according to sites irrespective of times. Geochemical behaviors are very similar indicating similar basic characteristics of source clay. However, loss-on-ignition showed 0.01 to 12.59wt.% range with a large deviation but it rapidly decreased moving from the Prehistoric times to the Three Kingdom Period. They have correlation with the weight loss due to firings, according to burning degree of source clay and detection of high temperature minerals, estimated firing temperatures are classified into 5 groups. Pottery in the Neolithic Age and in the Bronze Age belongs from 750 to $850^{\circ}C$ group; pottery in the Three Kingdom Period are variously found in 750 to $1,100^{\circ}C$ range of firing temperature; and it is believed celadon and white porcelain were baked in high temperature of 1,150 to $1,250^{\circ}C$. It seems difference between refinement of source clay and firing temperature based on production times resulted from change in raw material supply and firing method pursuant to development of production skill. However, there was difference in production methods even at the same period and it is thought that they were utilized according to use purpose and needs instead of evolved development simply to one direction.

• Journal of Energy Engineering
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• v.12 no.3
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• pp.197-206
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• 2003

A numerical analysis of the pulse-jet cleaning characteristics in a porous ceramic candle filter system was performed. To obtain the detailed velocity and pressure distribution during the cleaning process in a porous filter system, the axi-symmetric compressible Navier-Stokes equations including energy conservation equation were solved by using the FLUENT code which adopts FVM (Finite Volume Method). The effects of pulse cleaning nozzle diameter, nozzle tip position, permeability of a porous ceramic candle filter, diffuser throat diameter, and cleaning pressure on the cleaning flow characteristics were investigated extensively.

• Transactions of the Korean Society of Automotive Engineers
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• v.2 no.5
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• pp.58-65
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• 1994

In order to reduce particulate emissions from diesel vehicles, mathematical model is established and analyzed on ceramic wall-flow monolith filter. A wall-flow monolith filter placed in the exhaust stream of a diesel engine can effectively limit the emission of diesel particulates through the monolith. The accumulated particulates can then be periodically combusted inside the monolith by directing hot gas to the monolith while normal engine exhaust is routed around the monolith system. The resulting low flow rates through the monolith require consideration of gas dynamics through the channels as well as particulate combustion to analyze this regeneration process. A mathematical model of the regeneration is formulated as a system of nonlinear partial differential equations describing the conservation of mass, momentum and energy. Numerical solutions are obtained by using a finite difference techniques for the spatial discretization. So we can use filter simulation program for the purpose of filter design and actual filter regeneration

• Conservation Science in Museum
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• v.17
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• pp.101-116
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• 2016

Ceramic cultural artifacts restored with gypsum-based materials are prone to decay over time due to gypsum's natural absorption and release of atmospheric moisture, often leading to distortion and peeling of painted layers. This study proposes a new restoration material which utilizes extra hard stone, significantly superior in strength to regular gypsum. In order to enhance its physical properties and make it suitable for restoration of ceramics, extra hard stone is mixed with metakaolin. This mixture far surpasses regular gypsum in compressive strength(119MPa vs. 26MPa) while also maintaining a much lower wear rate(0.88% vs. 2.53%). Furthermore, the water absorption rate(2.9%) of the mixed material is over five times lower than that of regular gypsum(17.2%). When examined using a SEM(Scanning Electron Microscope), this mixture also proved superior to extra hard stone in terms of hardened density. The addition of metakaolin increases the mixture's strength and water resistance over that of extra hard stone and also improves its surface density, making it ideal for the restoration of ceramics. It has already been used to repair ceramic objects in the Museum's collection: Clay basin(sinan 18892), Buncheong ware bottle with incised peony design(jubsu 2034), Buncheong ware bowl with chrysanthemum(jubsu 1730). Results thus far have shown the mixture to be easy to inject and layer as well as harden into an even surface, which allows for smooth application of paint for color matching.

• Conservation Science in Museum
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• v.22
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• pp.85-96
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• 2019

The restoration of ceramics excavated in fragments is limited by the difficulty of inferring the overall shape of the original object. However, recent innovations in digital technology can help to overcome the limits of conventional restoration using handwork. This study explored the potential of digital technology by digitally restoring a shard from a white porcelain water dropper excavated at a kiln site at Sindae-ri. In order to complete the digital restoration, 3D scanning was applied to obtain scan data, and 3D modeling and texture mapping were performed. In this way, three-dimensional data with patterns and color information was acquired and the original form of the water dropper could be ascertained based on the shard. The study found that the data acquired from digital restoration can be used for various purposes, including for obtaining data on cross-sections or missing portions of a relic.

• Journal of Conservation Science
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• v.33 no.4
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• pp.275-281
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• 2017

The purpose of this study was to carry out radiocarbon dating using a wiggle match, of wooden boards and grains from the Mado shipwreck No. 4, which was excavated from Mado in Taean-gun, Chungcheongnam-do. The result of the wiggle matching for four decennial tree-ring samples of the stern plank produced a ${\pm}2{\sigma}$ radiocarbon date (95.4% confidence interval) of A.D. 1337-1356 or A.D. 1412-1429. The grains produced a ${\pm}2{\sigma}$ radiocarbon date (95.4% confidence interval) of A.D. 1415-1455. This indicated that the Mado shipwreck No. 4 belonged to the early or middle of the 15th century. These radiocarbon dating results correlate with the date that was speculated by archaeologists according to the ship's structure and ceramic style.

• Journal of Conservation Science
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• v.34 no.5
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• pp.359-368
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• 2018

The purpose of this study was to analyze the wood species of the stern plank and persimmon seed from Daebudo shipwreck No.2 excavated from Daebudo, Danwon-gu, Ansan-si, and Gyeonggi-do by wiggle-matching of radiocarbon measurements. Results of the analysis showed that all the wooden boards of the hull were made from Pinus Hard Pine Group. The other parts of hull and wooden pegs were made from Pinus Hard Pine Group, Castanea spp., Quercus spp. sect. Lepidobalanus, Alnus spp., and Zelkova serrata Makino. Excavated wide-tooth wooden comb and fine-tooth bamboo comb were made from Acer spp. and Bambusoideae. Excavated rope was made from Pueraria thunbergiana Benth. The stern plank, wooden support, and persimmon stone showed ${\pm}2{\sigma}$ radiocarbon date(95.4% confidence interval) of AD 1151-1224. This indicated that the Daebudo shipwreck No.2 occurred during the early or middle 12-13th century. Our radiocarbon dating results confirmed the date speculated by archeologists based on the ceramic style.

• Journal of Conservation Science
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• v.27 no.1
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• pp.115-121
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• 2011

A Urethane resin restoration material was made to be used in the restoration of stone cultural assets. The Urethane resin restoration material showed strong adhesive strength and tensile strength similar to epoxy recovery material, which had been mainly used for the recovery of stone cultural assets. The sealing property, anti-shrinking property and paint-ability of Urethane resin restoration material are also similar to existing epoxy system restoration materials. Especially, this Urethane resin restration material is expected to give permanence and continuous stability in the restoration of cultural assets made in stone by resolving the two big issues of existing epoxy recovery material, which are 'yellowing' and 'ir-reversibility'. This Urethane resin restration material had been directly applied as a filling material and adhesive and it was dissolved again. The Urethane resin, which had been used for the recovery, was able to be perfectly removed, which means that this Urethane resin recovery material has perfect reversibility. This Urethane resin restoration material also has enhanced convenience since user can adjust the working-life dependent on work environment. It is believed that this Urethane resin restoration material can also be used as a filling material or adhesive for other cultural assets made of ceramic or metal heritage, in addition to stone, since it has strong adhesive strength and tensile strength.

• Journal of Conservation Science
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• v.25 no.4
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• pp.451-464
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• 2009

To do conservation for ceramics, sometimes it needs to clean the ceramics chemically to remove stains on the ceramics, which should be performed with caution. This study will provide quantitative data about the extraction characteristics of major elements from ceramics through the soaking test to evaluate the stability of ceramic cleaning agents. As soft textured pottery(fired at $700^{\circ}C$) had high absorption, it showed higher extraction characteristics in short soaking time. Especially the strong acid among chemical cleaning agents caused the expoliation and the color change on the surface of soft textured pottery. But these color change had no effect on the physical characteristics of soft textured pottery. The hard textured pottery(fired at $1,000^{\circ}C$) is relatively stable in the cleaning agent because it is ascertained the extraction of that was not enough and also it had little chromatic and physical change by strong acid. Porcelains(Celadon, Whiteware and Puncheong ware) was safer than the soft textured pottery due to their low extraction. But it should take precautions to clean the porcelains with lots of cracklewares such like Puncheong ware chemically in connection with the extraction characteristics and their cracklewares.

• Journal of Conservation Science
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• v.36 no.5
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• pp.306-314
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• 2020

The use of synthetic resins in ceramic restoration poses several challenges, including aging and potential damage to artifacts, which has raised the need to investigate new materials and restoration methods. This study set out to incorporate full color 3D printing into the 3D digital technology-based restoration method, an emerging approach currently being researched, and to print out missing parts with color information. After examining material physical properties with an experiment, the investigator printed out missing parts from a white porcelain vessel and grayish-blue-powdered celadon plate and compared them in chromaticity and brilliance. The experimental results show that the outputs had comparable tensile strength to the original restoration materials, whereas the recorded compressive strength was approximately 1.4~2 times higher than that of the original restoration materials. According to the NIST table of color difference values, the white porcelain vessel was visible at ΔE^*ab 1.55, and the grayish-blue-powdered celadon plate was perceivable at 3.34. Even though it was impossible to express the colors accurately owing to printer limitations, this non-contact approach reduced the possibility of damage to the minimum. In conclusion, it can be applied to objects with a high chance of damage or generate display effects through purposeful color differentiation in missing parts.