Earticle

Wooden architectural heritages in Korea have been severely damaged by termites, and this damage is expected to increase owing to climate change. This study aimed to evaluate the changes in termite damage risk due to climate change specifically in Korean wooden architectural heritages. A multiple regression equation was developed to estimate the daily average temperature from the location information (latitude, longitude, and elevation) for 40 years (1980-2019). The location information of 106 nationally designated wooden architectural heritages distributed across 84 cities was used to estimate the daily mean temperature of each cultural heritages. Referring to a previous study on the ecological characteristics of R. speratus, a dominant termite species in Korea, the temperature at which termite activity is possible was confirmed, and the amount of wood consumed in relation to the temperature change was estimated. Based on this, the number of days available for termite activity and the amount of termite wood intake in the 1980s, 1990s, 2000s, and 2010s were estimated. Consequently, we found that the number of active days for termites increased from 243 to 249, 251, and 253 days in each decade. The wood consumption rate also increased by 9.9% over 40 years, from 6,657 to 6,777, 7,008, and 7,314 μg/ worker/year, respectively. This study was the first to estimate the activity period and wood intake of termites in Korea’s wooden architectural heritages, thereby providing valuable information for the preservation and management of these wooden heritages.

Asian lacquer is a material that has been used in Asia from ancient times to coat the surface of objects. It is a durable material, but is known to be weak to ultraviolet light (UV). Here, to understand the deterioration characteristics of Asian lacquer due to UV, the changes were analyzed using ultraviolet photometry, IR, and pyrolysis/GC/MS (pyrolysis/GC/MS), after exposing the lacquer coating film to UV (λ= 340 nm). In the ultraviolet photometry, the surface exposed to UV showed fluorescence. In IR analysis, the powder sample showed little change after exposure to UV, but on the surface, C = O groups increased, while C―H groups decreased significantly. Analysis with pyrolysis/GC/MS revealed that the composition of organic acid increased significantly. Carboxylic acids having 9 or less carbon atoms and dicarboxylic acids were significantly increased compared to carboxylic acid having 16 carbon atoms. In addition, urushiol with the oxidized side chain was also increased. This shows that the penetration depth of UV is the limiting factor for deterioration, and that the deterioration of lacquer due to UV proceeds with the destruction of carbon–carbon single and double bonds and the subsequent formation of carboxylic acid.

Bronze wares made with forged high-tin bronze technology were first produced in the Persian region of the Orient, gradually brought to India and then to China and the Korean Peninsula. By scientifically analyzing bronze artifacts of Myanmar, which is located halfway between Persia and Korea, it is possible to confirm the trade and the propagation route of technology at the time. This study scientifically analyzed bronze artifacts excavated from the Bagan ruins in Myanmar to identify the manufacturing technology. Forged high-tin b ronze wares in Bagan Dynasty a re with a lloy compositions Cu-Sn. Composed of Cu-Sn only were manufactured by alloying Cu with Sn in a ratio of 76 wt% and 24 wt%, which is a relatively high tin content. High-tin bronze wares composed of Cu-Sn were manufactured with the bronze material of an alloy of Cu and a large amount of Sn by hot working (forging) and finished by quenching. The microstructure indicates temperatures at which the quenching was performed and various microstructures that occur in different temperature ranges are observed such as β (M), γ phase, δ phase as well as primary crystals, α phase. The presence of different microstrucures suggests multiple high-tin bronze wares were quenched at a wide range of temperatures. The non-metallic inclusions of the bronze wares contain sulfur, which indicates with high possibility that the copper provided as the raw material was extracted from copper ores containing sulfur.

In this study, 91 samples were collected by layer, direction, and point from the smelting experiment furnace wall, and XRD analysis was performed. These data were compared with the geothermometer method and the cluster analysis method to determine how to effectively interpret heated characteristics. As a result of comparing the heated characteristics of the 1st to 4th floors, its showed the same results for both methods because of heated by high temperatures in the 1st and 2nd floors heated. However, in the data from the 3rd and 4th floors, it was difficult to interpret the difference in heat temperature depending on the direction using the geothermometer method, but the cluster analysis method was able to effectively confirm the pattern of heat spreading from the center to the outside of the furnace wall. As a result, the cluster analysis method can reduce errors that may appear due to mineral identification in the process of estimating heat temperature using the geothermometer method and there is an advantage in that the temperature distribution within the furnace wall can be further refined.

In this study, a gel cleaning experiment was conducted to stably remove the fixative (PVAc) used in the past conservation treatment of the mural painting of the Payathonzu temple. This study prepared mock-up samples reflecting the material properties and conservation status of the mural painting of the Payathonzu temple, and conducted an experiment about the applicability of 6 types of gel cleaners to discern potential changes when they are applied to the actual mural painting and to review their stability. This study found that the gel cleaner mixed with dimethyl carbonate had a superior removal effect to the gel cleaner mixed with acetone. Furthermore, for the same solvent, the gelling agent showed the removal effect in the order of Nevek® > Carbopol®980 > Laponite®RD. Upon examining change patterns after applying the cleaners, this study found that the cleaners with a superior removal power had a similar trend to that in removal effect evaluation in a previous study. In actually applying to the mural painting, however, the cleaners showed some inconsistent results with those in removal power evaluation, and it was confirmed that these results were attributable to the properties of the cleaners interacting with the properties of the mural painting and the extent of penetration of the fixative. It was also found that not only the conditions of the cleaners but also the material and painting technique characteristics of the mural could have a huge effect during the removal of the fixative. What is most important in removing the fixative applied to the mural painting of the Payathonzu temple is to ensure the stability of its painting layer by using a cleaning method that is controllable by the person treating the painting, and then, the properties that can help to effectively remove the fixative are required. At a time whenthere are few related studies in Korea, this study and its method may serve as a reference for future research on the removal of the fixative applied to a mural.

The aim of this study was to develop a natural cleaning agent for the conservation treatment of excavated gold leafed clothing artefacts and to test the stability of its application. To this end, a natural cleaning agent was formulated by mixing the extracts of Platycladus orientalis with natural cleaning aids prepared using coconut oil, rice kernel oil, and castor oil. The prepared natural cleaning agent was found to have better cleaning power and stability as a cleaning agent for clothing relics, compared to Saponin, Decyl glucoside, and Triton X-100, which have been conventionally used as cleaning agents for excavated clothing relics. A comparison of the four types of cleaning agents showed that the natural cleaning agent prepared with the extracts of Platycladus orientalis has significantly better cleaning power compared to three low and high concentration cleaning agents that have been used as cleaning agents for clothing relics. The findings show that the pH of the prepared natural cleaning agent was neutral, ranging from 6.61 to 6.93, indicating very weak acidity, the natural cleaning agent did not cause any pH related problems to the fabric during or after cleaning, and the prepared natural cleaning agent can be used as a stable natural agent for clothing relics because it has better cleaning power than the other conventional cleaning agents even at a relatively low concentration of 0.5% to 1.5%, a treatment time of 30 min., and a temperature below 30°C, a temperature which is not damaging to clothing relics.

Physical and chemical investigations were conducted on lime sample from Anak Tomb No.3 to determine the properties of the plaster material. The morphological and physical characteristics of the specimens were analyzed using both a microscope and a polarizing microscope. The constituent materials were identified through X-ray diffraction and scanning electron microscope-energy dispersive spectrometer, and the qualities of the mixed material were established through thermal analysis. Additionally, micro-computed tomography was used to non-destructively confirm the internal structure and density characteristics. The lime sample was recognized as a lime plaster material with two unique layers. Each layer shows variations in material properties. It is speculated that this lime specimen was used to finish the edges of the authentic wall within Anak Tomb No.3. Through the synthesis of various morphological attributes and physical properties; the whiteness, durability, thinness, and repetition of the layers, as well as smoothness of the lime plaster used for Anak Tomb No. 3 indicate that a high level of lime wall plastering technique was used in Goguryeo Tomb. It was possible to evaluate the refined level of lime wall manufacturing technology in the Goguryeo era.

This study conducts a metallurgical analysis of three swords with ring pommels (Hwandu sword) manufactured during the Proto–Three Kingdoms period and the Baekje period and excavated from the Asan and Cheonan. Specifically, we carried out analyses based on a metallurgical microscope, scanning electron microscopy with energy dispersive spectroscopy. the swords were made of bloomery iron produced through direct smelting and formed by hammering hypoeutectoid steel. It was also confirmed that other heat treatment techniques than shaping were not applied to them. In addition, all of them have a high carbon content and the crystal grains are well refined, so it is believed that the hardness and strength are high. Moreover, the analytic results of nonmetallic inclusions, No.2 swords have glassy slag and the others verified the existence of fayalite and wüstite on the glassy matrix. And a high Ca content overall. The results of comparing the swords with other swords with ring pommels excavated from the corresponding region indicated that heat treatment techniques were not applied to these artifacts despite the existence of such techniques. Thus, we analyze that the study subjects were produced as ceremonial items rather than weapons. Furthermore, the calculation results of ratios, such as CaO/SiO2 and (Al2O3/SiO2)/(CaO/SiO2), indicate that the study subjects were produced based on a similar smelting processing system. Based on the analytic results, this study also suggests a possibility of the addition of slag generation agents or the use of iron ores with a high Ca content.

This study conducted a cross-sectional analysis of 10 beads and a surface analysis of 38 beads among 48 glass beads excavated from the Naedeok-ri site in the Gimhae region, Korea. According to the cross-sectional analysis results, all glass beads were cobalt blue, and depending on the period, the bead colors from wooden coffin tomb No. 19 from the Proto-Three Kingdoms period and wooden coffin tomb No. 92 from the Three Kingdoms period were determined to be ultramarine and Wedgewood blue. According to the surface analysis results, the colors of the beads were divided into blue from the Proto-Three Kingdoms and Three Kingdoms eras, and brown from the Joseon Dynasty. Furthermore, the size of the beads was estimated to be Gimhae “small-sized”. These small beads were popular until the late Gaya period. As a result of analyzing the composition of the glass, only potash 1 type was confirmed in the cross section, but lead, potash, and soda glass were confirmed in the surface analysis. This is because glass from the Proto-Three Kingdoms period was easily broken, and glass from the Three Kingdoms period was excavated relatively complete. Through this study, Gimhae Naedeok-ri is confirmed to be a group that uses glass with various ingredients. These results reveal a trend moving in the following order: lead-barium Ⅱ → potash Ⅰ⋅Ⅱ → soda alumina → potash Ⅲ⋅lead glass.

During the dismantling of the cella of the Hong Nang Sida temple in Laos, 100 highly significant Yoni-monument members were recovered as fragmented individual stones. To restore the Hong Nang Sida temple to its former glory, it is necessary to restore the fragmented Yoni-monument members to their original positions. However, the high weight and low mobility of the stones make it difficult to physically reassemble the story members. Therefore, this study utilized three-dimensional (3D) scanning, modeling, and printing technologies to digitally reassemble the Yoni monument. To achieve this goal, optimization modeling was performed to connect the three-dimensional (3D) scanning data of individual fragmented stones, after which each story member was reduced to a 1/5 of its original size and printed by sand printing to evaluate the feasibility of physical assembly. Finally, 3D scans of the Yoni monument assembled using the sand-printing outputs were taken, and all the story members were virtually aligned based on the scan data to complete the digital reassembly. We believe that the results of this study will improve the feasibility and completeness of the physical reassembly by allowing for a full preliminary examination of stone blocks, which would otherwise be difficult to achieve because of the risk of secondary damage or weight limitation. In particular, it is possible to objectively and visually illustrate the geometric relationship between the members of each story, which can be extended to similar stone-based cultural heritage sites. To broaden the utility of the digital-reassembly model, it must be evolved into a historic building information model that links the unstructured data, including documents, photos, and images, obtained throughout the process life cycle.