• Economic and Environmental Geology
• /
• v.55 no.3
• /
• pp.281-293
• /
• 2022

We examined degradation characteristics of lead based pigments(white lead, Red lead, Litharge) according to atmospheric environmet condition, for example atmospheric gas(CO₂, NO₂) and soluble salt. Painted samples not changed material compositions but were occured the color change(𝚫E 4~31) after exposed UV irradiation. All sample were not affected by CO₂ gas not only color but chemical composition. However, samples were remakably changed color exposed NO₂ gas and it was formed secondary product like as lead nitrate. Such as red lead and white lead samples' color difference were 𝚫E 2 and 𝚫 10 respectively and became dark, along with litharge became bright and color difference was 𝚫E 5 after react with NO₂ gas. It confirm that NO₂ was influential factor than CO₂ in the case of same concentration. Furthermore salt spray test was taken to figure out soluble salt influence in fine dust. The result showed noticeable color change and secondary product was formed on samples' surface. The glue film peeled off or hole, and color changed around the secondary products. After salt spray, XRD pattern showed decrease peak intensity and lower crystalinity. As a result of salt spray test, white lead was formed new product litharge and litharge was formed litharge and minium. According to the results, influential atmospheric factors for conservation of paint pigments were UV, NO₂, soluble salt, and litharge was most weakness throughout lead base pigments.

• Journal of Conservation Science
• /
• v.36 no.6
• /
• pp.440-455
• /
• 2020

This study aims to examine the material characteristics of bowls and compare the making techniques of flat cup with cover and jar coffin from the Oryang-dong kiln site, Naju. Bowls, the most frequently excavated small pottery have similar material characteristics, including gray surface, fine-grained texture, and small-sized tempers such as quartz and feldspar, regardless of the excavation slopes. However, the firing temperature of the bowls mostly ranges from 950 to 1,100 ℃. It is estimated that the bowls had formalized making techniques, owing to the similar material composition and firing technique regardless of the excavation slope. The flat cups with cover have similar texture and mineral phases, except their poorly sorted inclusions. However, the jar coffins contain not only fine-grained minerals but also medium-grained quartz, feldspar, and biotite, showing a relatively wide range of firing temperatures. According to the geochemical results of pottery by type, it is assumed that chemical compositions are classified into two groups: small pottery(bowl and falt cup with cover) and jar coffins. In conclusion, small potteries such as bowls and flat cups with cover were made by removing the heavy minerals from raw materials, whereas jar coffins were made by adding medium-grained minerals to raw materials to maintain and support their structures, despite the same source materials. In addition, it is presumed that pottery making proceeded by selecting the source materials, preparing according to their use and controlling the firing temperature and environment.

• Journal of Korea Foundry Society
• /
• v.41 no.4
• /
• pp.349-356
• /
• 2021

Effects of cooling condition after solidification on the microstructure and the mechanical properties of 0.36Mn containing ductile cast iron have been studied based on the minimized addition of Cu and Sn for vehicle component applications with better quality and cost competitiveness. Cu and Sn were selected for additional elements judging from the well-known fact of strong tendency of pearlite promotion followed by the tensile property improvement. After pouring of the Mg treated cast iron melt with various chemical compositions into the block specimens, two ways of post solidification cooling conditions were applied for comparison; both cooling in the mold and cooling in the air after dismantle at 800℃. The pearlite fraction of the mold-cooled specimens was analyzed as 27-44%, with the tensile strength and elongation of 513-568N/mm² and 10.4-14.3%, respectively. Whilest, the air cooled specimens showed the pearlite fraction of 77~85%, with the tensile strength and elongation of 728~758N/mm² and 3.2~6.0%, respectively. It is worthwhile to note that the remarkable improvement of both tensile strength and elongation of the ductile iron was achieved by the present air cooling condition with the minimized combined addition of Cu and Sn to the 0.36Mn containing ductile iron.

• Economic and Environmental Geology
• /
• v.55 no.5
• /
• pp.447-463
• /
• 2022

The lime and clay that used in the construction of the Tomb of King Muryeong and the Royal Tombs in Gongju are auxiliary materials, and are used joint and plaster materials for the wall to play a role of structural support. In this study, the homogeneity between the tombs and material characteristics were interpreted through quantitative analysis of lime and clay. As a result of microtexture and composition analysis, almost the same minerals were identified in each sample groups, and similar characteristics were shown in thermal analysis. Geochemically, it is confirmed that the behavior characteristics are very similar regardless of the tombs. The compositions is also confirmed high homogeneity in the diagrams of CaO-MgO-SiO₂, RO₂-(RO+R₂O) correlations, A-CN-K and A-CNK-FM triangles. Therefore, it is interpreted that the clay used for the construction of the tomb complex was supplied from around area, and the raw materials of lime were produced using shell fragments of oyster family based on mainly composed of calcite. It is interpreted that the raw materials of lime were supplied from middens along the west coast of down the Geumgang river in Korean peninsula, but the consideration of the supply site, needs to be cross-validated through stable isotope analysis, use of carbonate rock and reproduction experiments.

• Journal of Marine Bioscience and Biotechnology
• /
• v.14 no.1
• /
• pp.1-8
• /
• 2022

This study examined the growth, fatty acid (FA) content, and carotenoids of a newly isolated freshwater microalga, Mychonastes sp. 246, in various culture media. The appropriate temperature and light intensity for culturing Mychonastes sp. 246 were determined as 18℃-22℃ and 200-250 µmol/m²/s using a high throughput photobioreactor. The microalgal cells were cultivated in 0.5 L bubble column photobioreactors using BG11, Bold's Basal media, and f/2 media. According to the growth results of the microalgae, BG11, among the tested media, showed the highest biomass concentrations (3.5 ± 0.1 g/L in 10 d). To enhance the biomass growth of the microalgae, the N:P ratio in BG11 was manipulated from 45:1 to 7:1 based on the stoichiometric cell composition. The biomass concentrations of Mychonastes sp. 246 grown on the manipulated BG11 (MBG) increased to 38% (4.6 ± 0.3 g/L in d) compared with the original BG11 (3.3 g/L). The FA content of the microalgae grown on the MBG was lower (8.4%) than that of the original BG11 (10.1%) while the FA compositions did not exhibit any significant differences. Furthermore, three kinds of carotenoids were identified in Mychonastes sp. 246, zeaxanthin, lutein, and β-carotene. These results suggest an effective strategy for increasing biomass concentrations, FA content, and carotenoids of microalgae by performing a simple N:P adjustment in the culture media.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.33 no.1
• /
• pp.38-47
• /
• 1988

To determine the response of soybean cultivars to nitrogen in relation to acidity, nodulation, content of allantoin nitrogen and major chemical compositions of soybean plants were investigated with two cultivars under two levels of soil pH and four levels of nitrogen fertilization in a field and nutri-culture experiments. Nodulation and contents of allantoin nitrogen, total nitrogen, potassium, calcium, magnesium and manganese of soybean plants decreased under acidic condition, but the degree of decrease was smaller in the variety Jangbaegkong compared to the variety Danyeobkong. On the other hand, nodulation, content of allantoin nitrogen and potassium decreased with increased nitrogen fertilization, particulary under pH 7 condition. Nodulation was positively correlated with the content of allantoin nitrogen of soybean plants. The content of total nitrogen of soybean plants increased with increased nitrogen fertilization, and this tendency was remarkable under acidic condition and in the variety Jangbaegkong.

• Journal of Practical Agriculture & Fisheries Research
• /
• v.7 no.1
• /
• pp.109-117
• /
• 2005

This study was carried out to determine effects of the feeding length of spent mushroom composts from selenium-enriched mushroom (Se-SMC) on meat quality and carcass characteristics in finishing Hanwoo steers. A total of 20 steers were used in this trial with four treatments. Treatments included control (no Se-SMC), Se-SMC groups of three different feeding lengths (2, 4, and 6 months). After the completion for each feeding length, steers were slaughtered and then loin muscle (Longissimus dorsi) was sampled to evaluate meat quality characteristics. Chemical compositions of the loin, except for protein content, were not different across treatments. Protein content was highest in 6 months feeding groups, however, it was lowest in 4 months. Physical property and meat color (L*, a* and b* values) were not affected by the feeding length of Se-SMC. However, water holding capacity (WHC) for Se-SMC feeding treatments was significantly more improved (p<0.05) in comparison with the control group, showing 63.8 (2 months), 64.4 (4 months), 64.2 (6 months), and 59.5% (control), respectively. Grades for meat quality and quantity, and carcass characteristics were not affected by feeding length of Se-SMC. Our results showed that Se-SMC supplementation was not significantly associated with parameters for meat quality and carcass characteristics. However, as feeding Se-SMC lengthens, WHC for loin was more improved, suggesting that the improved WC may result in the expression of antioxidant effect.

• Economic and Environmental Geology
• /
• v.56 no.6
• /
• pp.675-695
• /
• 2023

The tracksite of dinosaurs and pterosaurs in Sanbuk-dong of Gunsan is the largest early Cretaceous dinosaur footprint fossil site in Korea, and all the footprints are important evidence indicating that large ornithopod and theropod dinosaurs inhabited the Korean peninsula during the early Cretaceous. The Sanbuk-dong site was covered with waterproof sheet in an outdoor environment until the installation of a protective enclosure in 2021. As a result, various factors such as shear force, load reduction, temperature and humidity fluctuations, acid rain, salinity and microorganisms have complexly interacted in the substrate of fossils, exacerbating the damage to footprints. For 159 footprints in 12 trackways among the footprints found in the site, the damage types were classified in detail and the level of each damage was assessed. The damages were classified into 6 types through the classification of deterioration degree of individual footprints. As a result of ultrasonic physical property evaluation on the surface of the fossil site, most of these footprints are in the completely weathered (CW) stage. Furthermore, various weathering patterns were observed in the study area, and surface contaminants were analyzed along the stratigraphy. Although the patterns of freshness and contaminants varied at different points within the fossil site, the chemical compositions were similar. Based on the results, an efficient conservation management system for dinosaur footprint fossils was established, and a conservation treatment type for each footprint was proposed.

• Applied Chemistry for Engineering
• /
• v.34 no.6
• /
• pp.665-669
• /
• 2023

The crude methylnaphthalene oil (CMNO) contains nitrogen compounds (NCs) such as quinoline (QU), isoquinoline (IQU), and indole (IN). These NCs in the CMNO are treated as impurities contained in the CMNO due to contamination of the atmospheric environment and unpleasant odors. In order to improve the quality of CMNO, this study examined the effect of extraction experimental factors on the reduction of NCs contained in CMNO using CMNO as a raw material and an aqueous formamide solution as a solvent, respectively. The increase in the volume ratio of solvent to feed in initial (S/F)₀ in initial increased the distribution coefficient of NCs and the selectivity of NCs in reference to 2-methylnaphthalene (2MNA). Additionally, an increase in operating temperature (T) increased the distribution coefficient of NCs but conversely decreased selectivity. The compositions of QU, IQU, and IN in the raffinate oil recovered through equilibrium extraction under a constant condition (volume fraction of water to solvent in initial (y_w,0) = 0.1, (S/F)₀ = 9, T = 303 K, liquid-liquid contacting time = 72 h) were reduced by about 58.5 wt%, 61.9 wt%, and 73.4 wt%, respectively, compared to those of CMNO. The formamide extraction method in this study was expected to be an effective reduction method for NCs contained in CMNO.

• Animal Bioscience
• /
• v.37 no.6
• /
• pp.1096-1109
• /
• 2024

Objective: This research aims to explore the nutritional and bioactive peptide properties of goat meat taken from various primal cuts, including the breast, shoulder, rib, loin, and leg, to produce these bioactive peptides during in vitro gastrointestinal (GI) digestion and absorption. Methods: The goat meat from various primal cuts was obtained from Boer goats with an average carcass weight of 30±2 kg. The meat was collected within 3 h after slaughter and was stored at -80℃ until analysis. A comprehensive assessment encompassed various aspects, including the chemical composition, cooking properties, in vitro GI digestion, bioactive characteristics, and the bioavailability of the resulting peptides. Results: The findings indicate that the loin muscles contain the highest protein and essential amino acid composition. When the meats were cooked at 70℃ for 30 min, they exhibited distinct protein compositions and quantities in the sodium dodecyl sulfate-polyacrylamide gel electrophoresis profile, suggesting they served as different protein substrates during GI digestion. Subsequent in vitro simulated GI digestion revealed that the cooked shoulder and loin underwent the most significant hydrolysis during the intestinal phase, resulting in the strongest angiotensin-converting enzyme (ACE) and dipeptidyl peptidase-IV (DPP-IV) inhibition. Following in vitro GI peptide absorption using a Caco-2 cell monolayer, the GI peptide derived from the cooked loin demonstrated greater bioavailability and a higher degree of ACE and DPP-IV inhibition than the shoulder peptide. Conclusion: This study highlights the potential of goat meat, particularly cooked loin, as a functional meat source for protein, essential amino acids, and bioactive peptides during GI digestion and absorption. These peptides promise to play a role in preventing and treating metabolic diseases due to their dual inhibitory effects on ACE and DPP-IV.