• Journal of Conservation Science
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• v.36 no.5
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• pp.421-429
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• 2020

This study examined the manufacturing process of a furnace wall excavated from the Songdu-ri Site in Jincheon, and the difference in material composition between the 11 layers of the wall using physicochemical analyses. Based on microstructure observations, these layers could be largely divided into three groups: an undercalcined first layer, calcined second to ninth layer with evidences of partial heat, and non-fired soil layers from the tenth to the eleventh layer. Particle size analyses revealed that the fired layer constituted a relatively higher content of coarse sand than the non-fired layer. This difference was further confirmed by the results of the curvature coefficient analysis. An analysis of the constituent minerals showed similar overall XRD diffraction patterns between the different layers, but variations in the intensity of the low-temperature and high-temperature minerals. This indicates that the degree of heat was different. The thermal analysis results demonstrated that the heating peak of mullite was only reached in the first and second layers of the wall, thus implying these as the layers to be finally used. Consequently, no significant difference could be observed between the materials of the various layers of the wall. Thus, it can be suggested that the furnace wall was constructed using clay, which had a composition similar to that of the soil present in the area. However, the shape and characteristics of the constituent particles between the layers displayed partial variations, and it is possible that some external materials might have been added.

• Journal of Conservation Science
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• v.27 no.1
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• pp.13-30
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• 2011

This study compared Pottery, Hwaecheongware, Buncheongware and Whiteware pieces excavated in Hakbong-ri of Chungnam analytically by observing their refined structures and estimating their firing temperature. As a result, base soil components of the specimens were mostly similar to those of typical Buncheongware, but the content of the fluxing agent was rather high, and it seemed that the Whiteware had been made with fairly different components from those of other sherds. Although the glaze showed less difference than base soil in general, the content of the glaze changed according to the decorating methods of Buncheongware. Based on the SEM-EDS analysis, it was found that the base soil components of the ceramics seemingly rather different were actually different and the analysis on the fine crystals of the base soil, the anorthite in the glaze and crystals in the ironing part, and the components and contents of white earth showed there were some noticeable points in the process of making each of the sherds. In the refiring experiment to estimate the firing temperature, mostly similar results were gained as $1150^{\circ}C$ to $1200^{\circ}C$ for pottery, $1100^{\circ}C$ to $1150^{\circ}C$ for Hwaecheongware, and $1100^{\circ}C$ to $1200^{\circ}C$ for iron-brown Buncheongware however, the results imply good quality Whiteware was burnt at above $1300^{\circ}C$ while bad quality Whiteware was burnt at a temperature far lower than that. Thus, there was clear difference between Whiteware sherds and other kinds of sherds.

• Resources Recycling
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• v.30 no.6
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• pp.53-60
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• 2021

In EAF steelmaking industries, MgO content in slag increases due to the addition of dolomite flux to protect refractory lines of furnaces and improve the desulfurization capability of slag. In addition, coal powder is injected in the molten steel bath to increase the energy efficiency of the process. In this regard, the utilization of waste MgO-C refractory material as a flux was examined because it has high amounts of MgO (>70%) and graphite carbon (>10%). A series of experiments were carried out using industrial EAF slag with added light burnt dolomite and waste MgO refractory material from a Korean steel company. The results for the addition of the two fluxes were similar in terms of slag basicity; therefore, it is expected that waste MgO-C refractory material can successfully replace dolomite flux. In addition, when the waste MgO-C refractory material was added as flux, slag foaming phenomenon was demonstrated because of the reaction between the graphite from the refractory material and iron oxides in the slag.

• Economic and Environmental Geology
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• v.56 no.6
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• pp.781-797
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• 2023

Recently, there has been a rapid response from mineral-demanding countries for securing critical minerals in a high tech industries. Graphite, while overwhelmingly dominated by China in production, is changing in global supply due to the exponential growth in EV battery sector, with active exploration in East Africa. Rare earth elements are essential raw materials widely used in advanced industries. Globally, there are ongoing developments in the production of REEs from three main deposit types: carbonatite, laterite, and ion-adsorption clay types. While China's production has decreased somewhat, it still maintains overwhelming dominance in this sector. Recent changes over the past few years include the rapid emergence of Myanmar and increased production in Vietnam. Nickel has been used in various chemical and metal industries for a long time, but recently, its significance in the market has been increasing, particularly in the battery sector. Worldwide, nickel deposits can be broadly classified into two types: laterite-type, which are derived from ultramafic rocks, and ultramafic hosted sulfide-type. It is predicted that the development of sulfide-type, primarily in Australia, will continue to grow, while the development of laterite-type is expected to be promoted in Indonesia. This is largely driven by the growing demand for nickel in response to the demand for lithium-ion batteries. The global lithium ores are produced in three main types: brine lake (78%), rock/mineral (19%), and clay types (3%). Rock/mineral type has a slightly higher grade compared to brine lake type, but they are less abundant. Chile, Argentina, and the United States primarily produce lithium from brine lake deposits, while Australia and China extract lithium from both brine lake and rock/mineral sources. Canada, on the other hand, exclusively produces lithium from rock/mineral type. Vanadium has traditionally been used in steel alloys, accounting for approximately 90% of its usage. However, there is a growing trend in the use for vanadium redox flow batteries, particularly for large-scale energy storage applications. The global sources of vanadium can be broadly categorized into two main types: vanadium contained in iron ore (81%) produced from mines and vanadium recovered from by-products (secondary sources, 18%). The primary source, accounting for 81%, is vanadium-iron ores, with 70% derived from vanadium slag in the steel making process and 30% from ore mined in primary sources. Intermediate vanadium oxides are manufactured from these sources. Vanadium deposits are classified into four types: vanadiferous titanomagnetite (VTM), sandstone-hosted, shale-hosted, and vanadate types. Currently, only the VTM-type ore is being produced.

• Korean Journal of Heritage: History & Science
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• v.37
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• pp.285-307
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• 2004

Synthesize and examine petrological characteristic and geochemical characteristic by weathering formation of rock and progress of weathering laying stress on stone cultural properties of Unjusa temple of Chonnam Hwasun county site in this research. Examine closely weathering element that influence mechanical, chemical, mineralogical and physical weathering of rocks that accomplish stone cultural properties and these do quantification, wish to utilize by a basic knowledge for conservation scientific research of stone cultural properties by these result. Enforced component analysis of rock and mineralogical survey about 18 samples (pyroclastic tuff; 7, ash tuff; 4, granite ; 4, granitic gneiss; 3) all to search petrological characteristic and geochemical characteristic by weathering of Unjusa temple precinct stone cultural properties and recorded deterioration degree about each stone cultural properties observing naked eye. Major rock that constitution Unjusa temple one great geological features has strike of N30-40W and dip of 10-20NE being pyroclastic tuff. This pyroclastic tuff is ranging very extensively laying center on Unjusa temple and stone cultural properties of precinct is modeled by this pyroclastic tuff. Stone cultural propertieses of present Unjusa temple precinct are accomplishing structural imbalance with serious crack, and because weathering of rock with serious biological pollution is gone fairly, rubble break away and weathering and deterioration phenomenon such as fall off of a particle of mineral are appearing extremely. Also, a piece of iron and cement mortar of stone cultural properties everywhere are forming precipitate of reddish brown and light gray being oxidized. About these stone cultural properties, most stone cultural propertieses show SD(severe damage) to MD(moderate damage) as result that record Deterioration degree. X-ray diffraction analysis result samples of each rock are consisted of mineral of quartz, orthoclase,plagioclase, calcite, magnetite etc. Quartz and feldspar alterated extremely in a microscopic analysis, and biotite that show crystalline form of anhedral shows state that become chloritization that is secondary weathering mineral being weathered. Also, see that show iron precipitate of reddish brown to crack zone of tuff everywhere preview rock that weathering is gone deep. Tuffs that accomplish stone cultural properties of study area is illustrated to field of Subalkaline and Peraluminous, $SiO_2$(wt.%) extent of samples pyroclastic tuff 70.08-73.69, ash tuff extent of 70.26-78.42 show. In calculate Chemical Index of Alteration(CIA) and Weathering Potential Index(WPI) about major elements extent of CIA pyroclastic tuff 55.05-60.75, ash tuff 52.10-58.70, granite 49.49-51.06 granitic gneiss shows value of 53.25-67.14 and these have high value gneiss and tuffs. WPI previews that is see as thing which is illustrated being approximated in 0 lines and 0 lines low samples of tuffs and gneiss is receiving esaily weathering process as appear in CIA. As clay mineral of smectite, zeolite that is secondary weathering produce of rock as result that pick powdering of rock and clothing material of stone cultural properties observed by scanning electron micrographs (SEM). And roots of lichen and spore of hyphae that is weathering element are observed together. This rock deep organism being coating to add mechanical weathering process of stone cultural properties do, and is assumed that change the clay mineral is gone fairly in stone cultural properties with these. As the weathering of rocks is under a serious condition, the damage by the natural environment such as rain, wind, trees and the ground is accelerated. As a counter-measure, the first necessary thing is to build the ground environment about protecting water invasion by making the drainage and checking the surrounding environment. The second thing are building hardening and extirpation process that strengthens the rock, dealing biologically by reducing lichens, and sticking crevice part restoration using synthetic resin. Moreover, it is assumed to be desirable to build the protection facility that can block wind, sunlight, and rain which are the cause of the weathering, and that goes well with the surrounding environment.

• Korean Journal of Heritage: History & Science
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• v.53 no.3
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• pp.62-79
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• 2020

The rock-carved seated Avalokiteśvara statue at Ganghwa Bomunsa Temple is a giant rock-carved Buddhist statue that was built in 1928 during the Japanese colonial era. Although it is a year-recorded Buddhist statue that occupies a prominent place in modern Korean Buddhist sculpture history, it has not been the subject of in-depth discussion due to weak research on modern Buddhist sculptures. In this study, to examine the various significant aspects of the rock-carved Seated Avalokiteśvara statue at Bomunsa Temple as a modern Buddhist sculpture, I have managed to determine its construction year, artificers, and patrons by deciphering the inscription around the rock-carved statue; in addition I have researched the effects of the rock shapes and landforms on the formation of the Buddhist statue by comparing and analyzing the points of view of both artificers and worshipers. I have also identified the specific circumstances of the time of construction from interviews with the descendants of artificers. A monk from Geumgangsan Mountain, Lee Hwaeung, took the role of sponsor and chief painter to construct the rock-carved seated Avalokiteśvara statue at Bomunsa temple. In the beginning of its construction in 1928, more than 100 donators jointly sponsored the construction of the statue. Gansong Jeon Hyoungphil sponsored alone at the time of the place of worship's expansion in 1938. Bomunsa Temple has been regarded as one of the top-three sacred places of Avalokiteśvara Bodhisattva together with Naksansa Temple in Yang Yang and Boriam in Nam Hae, due to the construction of the rock-carved statue. It took about three months to construct the statue. Lee Hwaeung drew a rough sketch and then Un Songhag and five masons from Ganghwa Island took part in the carving process. We can observe the line drawing technique around the rock-carved statue because the statue was carved based on the rough sketch of the monk painter. The aspect of Lee Hwaeung as a painter is revealed; therefore, we can identify the clue of painting pattern leading to Seogongchulyou- Hwaunghyoungjin- Ilonghyegag. The rock-carved seated Avalokiteśvara statue at Bomunsa Temple is a typical Avalokiteśvara that wears a jeweled crown and holds Kundica. It makes a strong impression as it has a big square-shaped face and a short neck and is unsophisticated in general. The artificers solved the issue of visual distortion of the rock-carved statue caused by carving on a 10-meter high and 40-degree sloping rock by controlling motion to its maximum, omitting detailed expression by emphasizing symmetry, and adjusting the head-to-body proportion to be almost one-to-one. In this study, especially, I presume the unified form of sacred sculptures and Buddhist altars, without making a Buddhist altar like the rock-carved seated Avalokiteśvara statue at Bomunsa Temple, to be a key characteristic of modern Buddhist sculptures. Furthermore, I make newly clear that the six letters of Sanskrit carved on nimbus, which had been interpreted as a Six-Syllable Mantra, are a combination with Jeongbeopgye and Sabang Mantras. In addition, three iron rings driven on eaves rock were used as a reference point, and after construction they were used as a decoration for the Bodhisattva with hanging wind chimes.

• Journal of Internet Computing and Services
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• v.25 no.1
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• pp.99-107
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• 2024

Along with economic growth and industrial development, there is an increasing demand for various electronic components and device production of semiconductor, SMT component, and electrical battery products. However, these products may contain foreign substances coming from manufacturing process such as iron, aluminum, plastic and so on, which could lead to serious problems or malfunctioning of the product, and fire on the electric vehicle. To solve these problems, it is necessary to determine whether there are foreign materials inside the product, and may tests have been done by means of non-destructive testing methodology such as ultrasound ot X-ray. Nevertheless, there are technical challenges and limitation in acquiring X-ray images and determining the presence of foreign materials. In particular Small-sized or low-density foreign materials may not be visible even when X-ray equipment is used, and noise can also make it difficult to detect foreign objects. Moreover, in order to meet the manufacturing speed requirement, the x-ray acquisition time should be reduced, which can result in the very low signal- to-noise ratio(SNR) lowering the foreign material detection accuracy. Therefore, in this paper, we propose a five-step approach to overcome the limitations of low resolution, which make it challenging to detect foreign substances. Firstly, global contrast of X-ray images are increased through histogram stretching methodology. Second, to strengthen the high frequency signal and local contrast, we applied local contrast enhancement technique. Third, to improve the edge clearness, Unsharp masking is applied to enhance edges, making objects more visible. Forth, the super-resolution method of the Residual Dense Block (RDB) is used for noise reduction and image enhancement. Last, the Yolov5 algorithm is employed to train and detect foreign objects after learning. Using the proposed method in this study, experimental results show an improvement of more than 10% in performance metrics such as precision compared to low-density images.