Earticle

Built in the 6th and 7th centuries during the Baekje period, the Buyeo Royal Tombs consist of seven tombs, including Tomb No. 1, which contains murals. To preserve Tomb No. 1 from damage caused by microorganisms, periodic microbial-distribution investigations are conducted. Following such investigations in August 2016, June 2018, and November 2019, the microbes were classified according to the investigation period, location of collection, and space. This study compares and analyzes the results. The concentration of airborne microorganisms in Tomb No. 1 and the number of microbial genera identified in each space of the tomb decreased as proximity to the main room with murals diminished. During the investigation period, the genera Bacillus, Cladosporium, Penicillium, and Streptomyces were commonly identified on Tomb No. 1. The microorganisms collected f rom the main room walls were mostly isolated from the east and west walls where the genera Bacillus, Cupriavidus, Paenibacillus, Pseudomonas, and Streptomyces were commonly identified in three or more walls. In particular, the genus Streptomyces is a dangerous strain capable of damaging murals by penetrating into and discoloring the pigments on them. The data generated from this study may be useful for future research on microbial distribution in other domestic mural tombs and those located in North Korea and abroad.

A long-term monitoring investigation at Sarushima Battery (Kanagawa, Japan), which is one of the modernization heritages was conducted from 2017.06 to 2020.12. The investigation of the temperature and relative humidity (RH), measurement of the amount of brick decay, and X-ray diffraction analysis of the brick decay was conducted to understand in detail the environment in which the historical brick structure, the state of deterioration, identify the factors of deterioration. Furthermore, it was discussed whether the suitability of these investigation methods for assessing the status, identifying the level of deterioration and the factors that led to deterioration at the historical brick heritages. It was found that the brick deterioration at the site progressed especially in two periods: in April, and from June to August. These periods coincided with the period when the RH inside the structure decreased, and the Toyo-gumi bricks were in the process of absorbing moisture. Several different types of salts were detected in brick decay, especially thenardite, which is considered highly hazardous and destructive during periods when the amount of brick decay increased. Therefore, the RH in the structure and the salts present in the bricks were identified as one of the factors in the deterioration of the bricks at the site. The methods used in this study are appropriate as the initial survey methods for investigating the current conditions and identifying the causes of deterioration because it is possible to understand the environment within the modernization heritages, grasp the details of deterioration progression, and identify the characteristics of deterioration progression and its factors through long-term investigation using the simple methods.

‘Eve 58-1’, the subject of this study is a statue made of plaster and its structural stability was evaluated by utilizing the CAE program in order to prevent the risk of damage arising from impact and vibration that are generated during the packaging and transportation process given its material characteristics. CAE is an abbreviation for Computer Applied Engineering for realization by predicting changes at the time of application of virtual physical energy. It is applied by reflecting the physical property conditions and each boundary condition of plaster, and the digital images of the internal and external structure of the work were acquired through 3D scanning and CT analysis for interpretation by executing finite element modeling. When acceleration is applied to the work in the direction of its own weight, the left-right side and the front-rear side, it was possible to confirm a maximum displacement value of 15.24 mm in the head section of the front-rear side direction that has been tilted by approximately 27° from the Y-axis and the largest stress value of 12.46 MPa was at the left ankle section. The corresponding results confirmed that the left ankle section is the most vulnerable area and the section for which precautions need to be exercised and supplemented at the time of transporting the work by means of objective values.

In the 6th and 7th centuries, 5 iron artifacts excavated form the Baekje Stone Tomb in Guryong-ri site, Ungcheon, Boryeong, were studied. The sample were metal microscopic observation, SEM-EDS analysis and Raman micro-spectroscopy analysis were conducted to understand the metallurgical characteristics. The microstructure observation showed the presence of ferrite and pearlite throughout, and differences in carbon content existed depending on the direction. Non-metallic inclusions were in the form of long lines, and most of them were wüstite, fayalite. It is indicated that the artifacts were forge welded using hypoeutectoid steel, with signs of carburizing and decarburizing processes. Some crystals with high P2O5, TiO2, CaO content were identified as sarcopside, ulvöspinel, and perovskite, respectively, through Raman spectroscopy. A comparison of the results with previous studies on the sites of Bujang-ri site in Seosan and Bongseon-ri site in Seocheon, which are adjacent sites in the coastal area, revealed that, while heat treatment technology was available, the artifacts were not heat-treated considering the purpose for use for these artifacts. The chemical composition of the non-metallic inclusions P2O5, TiO2, CaO were plotted in proportions to SiO2 and compared with adjacent sites. Considering that the P2O5/SiO2 ratio was widely distributed, the refining technology was not uniform. In addition, the TiO2/SiO2 ratio was found to be higher than that of other sites, meaning that a titanium-containing ore was used to manufacture the artifacts, unlike in surrounding sites, but it is not detected in all artifacts, so it may have been affected by various factors such as furnace walls in addition to raw materials. Although slag formers were used, considering the CaO/SiO2 ratio and the (Al2O3/SiO2)/(CaO/SiO2) ratio, which appear to be similar to the surrounding sites, but it is possible that CaO containing raw ore was used because it is also affected by the components of raw ore. As a result of the study, it is highly likely that ore different from that of the surrounding sites was used for production, but a more comprehensive comparative study with the surrounding sites is needed in the future.

We made a Korean white porcelain or Joseon Baekja jar and based on the raw materials used and reproductions of each stage, we aimed to compare and analyze the physicochemical changes of the raw materials such as clay at each manufacturing stage, as well as identify the characteristics and correlations. Although the basic main components of clay and glaze material are similar, their texture becomes denser in the process of bisque firing pottery (Chobeol-pyeon) and glaze firing pottery (Jaebeol-pyeon), and we confirmed that in addition to the tendency of increasing vitrification, low-temperature minerals such as mica and illite gradually disappeared, while high-temperature minerals such as cristobalite were newly created. This phenomenon has also been verified by the rapid decrease in absorption rate while the change in specific gravity was small. In addition, the color was greatly affected by the firing atmosphere, and the yellow-red chromaticity of the raw materials was higher during bisque firing but showed a rapidly decreasing characteristic during glaze firing. The value of magnetic susceptibility, which is related to iron (Fe) component, showed a tendency to decrease in glaze firing pottery. CT images were confirmed as a method that can indirectly estimate the change in the material properties of the object step-by-step for the entire object. In conclusion, the study of manufacturing stages of reproduction can provide basic data for scientific research on the estimation of porcelain and pottery making technology and changes in raw materials.

Investigation of conservation status, optical survey, infrared thermography, and ultrasonic examination were performed on Avalokitesvara Bodhisattva mural and Buddhist Monk Bodhidharma mural to determine the conservation status and physical properties. As a result of investigation of conservation status, the types of damage are largely divided into the wall and finishing layer damage, painting layer degradation, damage due to restoration materials, stains and contamination, and biological damage. As a result of the optical survey, drawing, stains, and repainted site were confirmed. Result of the infrared thermography, the delamination of the finishing layer was confirmed, and some locations and shapes of the wooden lath inside the wall were identified. The result of the 3D scanning, the deviation, and the separation of the wall was confirmed. As a result of ultrasonic examination, it was confirmed that the physical properties of the mural were identified and the ultrasonic speed was relatively low due to physical damage such as delamination and exfoliation of the finishing layer and cracking. Ultrasonic speed values were also high in some wall cracks or delamination, and it was confirmed by the infrared thermography results that the wooden lath inside the wall was located in those parts. It was possible to understand that the wooden lath inside the walls affects the ultrasonic speed during the ultrasonic examination. Therefore, management through periodic inspection of the relevant elements is necessary, and a countermeasure for damage that may occur in the future should be prepared along with intensive monitoring of the major damage identified in this diagnosis result.

Sri Lanka has four types of mural painting styles; Classic, Late Classic, Kandyan, and Southern styles, but there is little research on scientific analysis for mural paintings. In this study, we analyze white, yellow, and red clay pigments which were collected from ancient producing sites. Analyzing pigment samples shows that samples are containing aluminum oxide(Al2O3) and silicon dioxide(SiO2) which are connected to the soil. And a degree of iron oxidation determines yellow or red colors. To understand the characteristics of clay pigment samples, we go over previous pigment analyses of mural paintings in Sri Lanka. Kaolin is identified after the 17th century, yellow and red ochre are applied in early periods, Classic and Late Classic styles. The change in raw materials of pigments occurred in the 17th century.

The manufacturing technique was studied through the structure and material characteristics of the walls and the painting layers of the Avalokitesvara Bodhisattva mural of Geungnakjeon Hall, Daewonsa Temple. The mural is painted and connected to the earthen wall and the Junggit, and the wall is composed of wooden laths as a frame, the first and middle layers, the finishing layer, and the painting layer. The first layer, middle layer, and finishing layer constituting the wall were made by mixing weathered soil and sand. It was confirmed that the first layer had a high content of loess below silt, and the finishing layer had a high content of fine-sand and very fine sand. For the painting layer, a ground layer was prepared using soil-based mineral pigments, and lead white, white clay, atacamite, minium, and cinnabar (or vermilion) pigments were used on top of it. The Avalokitesvara Bodhisattva mural was confirmed to belong to a category similar to the soil-made buddhist mural paintings of Joseon Dynasty. However, it shows characteristics such as a high content of fine sand in the finishing layer and overlapping over other colors. Such material and structural characteristics can constitute important information for future mural conservation status diagnoses and conservation treatment plans.

Gongsanseong Fortress was registered of a World Heritage Site in 2015 as a representative cultural heritage from the Woongjin Baekje period, and it has been used throughout the entire period from Baekje Kingdom to the Joseon Dynasty. Within Gongsanseong Fortress, the area around Ssangsujeong is presumed the site of royal palace of the Woongjin Baekje. Also, the excavated culture layers of the Baekje Kingdom, the Unified Silla period, and the Joseon Dynasty were confirmed. In this study, paleotopography was modeled by digitally converting the elevation data obtained through surveying the excavation process, and the use of the topography in the Ssangsujeong area was considered by examining the variations in the topography according to the periods. As a result, the topography of the slope around the peak changed by periods, and the topography did not change on the flat land. The topography between the Baekje Kingdom and the Unified Silla period appeared to be almost identical, and it seems that the space of the Baekje period was maintained as it is. Also, during the Joseon Dynasty, it is confirmed that flat surfaces in the previous period were used. However, sediments on the slopes flowed down, reducing the area of the flatland, and architectural techniques that could utilize the natural topography of the changed slope were applied to interpret it as having a different topography from the previous period. In order to model and interpret the paleotopography, excavation data, geological and topographic analysis, and digital data must be secured. It is expected that location conditions and ancient human life can be identified if the analysis technique in the study is applied to other archaeological sites in the future.