• Economic and Environmental Geology
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• v.57 no.2
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• pp.161-175
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• 2024

Aggregate typically refers to sand and gravel formed by the transportation of rocks in rivers or artificially crushed, constituting a core resource in the construction industry. Gyeongsangbuk-do, the largest administrative area in South Korea, produces various sources of gravel, including forest, land (excluding other sources), river, and crushed stone. As of 2022, it has extracted approximately 6.96 million cubic meters of aggregate, with permitted production totaling around 4.07 million cubic meters and reported production of about 2.88 million cubic meters. The aggregate demand in Gyeongsangbuk-do is estimated to be 12.39 million cubic meters according to the estimation method in Ready-Mix Concrete. From the supply perspective, about 120 extraction sites are operational, with most municipalities maintaining an appropriate balance between aggregate demand and supply. However, in some areas, there is inbound and outbound transportation of aggregate to neighboring regions. Regions with significant inbound and outbound aggregate transportation in Gyeongsangbuk-do are areas connected to Daegu Metropolitan City and Pohang City along the Gyeongbu rail line, showing a high correlation with population distribution. Gyeongsangbuk-do faces challenges such as population decline, aging rural areas, and insufficient balanced regional development. Analysis using GIS reveals these trends in gravel demand and supply. Currently in this study, Gyeongsangbuk-do meets its demand for aggregate through the supply of various aggregate sources, maintaining stable aggregate procurement. River and terrestrial aggregates may be sustained as short-term supply strategies due to the difficulty of longterm development. Considering the reliance on raw material supply for selective crushing, it suggests the need for raw material management to maintain stability. Gyeongsangbuk-do highlights quarries in the forest as an important resource for sustainable aggregate supply, advocating for the development of large-scale aggregate quarries as a long-term alternative. These research findings are expected to provide valuable insights for formulating strategies for sustainable management and stable utilization of aggregate resources.

• Economic and Environmental Geology
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• v.57 no.2
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• pp.205-217
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• 2024

This study evaluated the physical characteristics and quality of volcanic rocks distributed in the Jeju Island-Ulleung Island area as aggregate resources. The main rocks in the Jeju Island area include conglomerate, volcanic rock, and volcanic rock. Conglomerate is composed of yellow-red or gray heterogeneous sedimentary rock, conglomerate, and encapsulated conglomerate in a state between lavas. Volcanic rocks are classified according to their chemical composition into basalt, trachybasalt, basaltic trachytic andesite, trachytic andesite, and trachyte. By stratigraphy, from bottom to top, Seogwipo Formation, trachyte andesite, trachybasalt (I), basalt (I), trachybasalt (II), basalt (II), trachybasalt (III, IV), trachyte, trachybasalt (V, VI), basalt (III), and trachybasalt (VII, VIII). The bedrock of the Ulleung Island is composed of basalt, trachyte, trachytic basalt, and trachytic andesite, and some phonolite and tuffaceous clastic volcanic sedimentary rock. Aggregate quality evaluation factors of these rocks included soundness, resistance to abrasion, absorption rate, absolute dry density and alkali aggregate reactivity. Most volcanic rock quality results in the study area were found to satisfy aggregate quality standards, and differences in physical properties and quality were observed depending on the area. Resistance to abrasion and absolute dry density have similar distribution ranges, but Ulleung Island showed better soundness and Jeju Island showed better absorption rate. Overall, Jeju Island showed better quality as aggregate. In addition, the alkaline aggregate reactivity test results showed that harmless aggregates existed in both area, but Ulleungdo volcanic rock was found to be more advantageous than Jeju Island volcanic rock. Aggregate quality testing is typically performed simply for each gravel, but even similar rocks can vary depending on their geological origin and mineral composition. Therefore, when evaluating and analyzing aggregate resources, it will be possible to use them more efficiently if the petrological-mineralological research is performed together.

• Food Science and Preservation
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• v.30 no.5
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• pp.822-832
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• 2023

This study investigates the effectiveness of CA (controlled atmosphere) containers in maintaining the freshness of exported melons. The melons were harvested on June 5, 2023, in the Yeongam area of Jeollanam-do, Korea. The CA container was loaded with melon samples packed in an export box. The temperature inside the container was set at 4℃, while the gas composition was set at 5% oxygen, 12% carbon dioxide, and 83% nintrogen. Following two weeks of simulated transportation, quality analysis was conducted at 10℃. The melons were inoculated with spore suspensions, and the decay rate was determined to investigate the effect of the gas composition inside the CA container on suppressing the occurrence of Penicillium oxalicum in melons. The results were compared with a Reefer container set at the same temperature. The samples transported in the CA container exhibited lower weight loss. The melon pulp softening, respiration rate, and ethylene production were slower using the CA container. Moreover, the decay rate during the distribution period in the CA container was lower than in the Reefer container. In contrast, the firmness of melons transported in the Reefer container decreased significantly (from 9.03N to 5.18N) immediately after transportation. The soluble solid content (SSC) of melons transported in the Reefer container also decreased rapidly. The results suggested that the CA container is the optimal export container for maintaining the freshness of melons.

• Information Systems Review
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• v.20 no.4
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• pp.1-23
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• 2018

A smart phone has been widely spread around world and makes people enjoy online shopping in any time and any place. Recently it also changes the distribution environment. O2O (Online-to-Offline) service becomes new normal due to its convenience of ease shopping of product and services. O2O service market shows steady and steep growth, It is reported that, however, 80% of the businesses has been discontinued within the first year because of unstable business models, customer dissatisfaction and distrust of service. Therefore, it is very important research issue to find out influential factors promoting continuous usage intention of O2O service. Previous study shows that it only considers online characteristics and lack of analysis about offline characteristics and social impact factors. The purpose of this paper is to find out continuous usage intention factors of O2O services by literature review, case analysis, and empirical test. A comprehensive research model and related hypothesis are developed and tested by using a structural equation, Survey was carried out among users who have used O2O service including payment service for at least once. Finally 611 samples are selected out of total 813 surveys. The result shows that the model is theoretically proved and 12 out of 17 hypotheses are accepted. The contribution of this paper is that it provides a new theoretical research model about continuous usage intention factors as well as practical guidelines about promoting continuous usage and growth strategies of O2O service.

• Research in Plant Disease
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• v.29 no.4
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• pp.384-389
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• 2023

Milling can affect the distribution of mycotoxins in small grains. To investigate the effects on barley, seven hulled barley and three naked barley samples naturally contaminated with trichothecenes and zearalenone were obtained and milled at commonly used rates. Both barleys were simultaneously contaminated with deoxynivalenol and its acetyl derivatives (98.1-2,197.8 ㎍/kg), nivalenol and its acetyl derivative (468.5-3,965.1 ㎍/kg), and zearalenone (4.1-274.2 ㎍/kg). Milling hulled barleys at a rate of 67% reduced the mycotoxins in the grain by 90.9% for deoxynivalenol, 87.7% for nivalenol, and 93.2% for zearalenone. The reduction in naked barleys (milled at a rate of 70%) was slightly lower than in hulled barleys, with 88.6% for deoxynivalenol, 80.2% for nivalenol, and 70.1% for zearalenone. In both barleys, the acetyl derivatives of deoxynivalenol and nivalenol were reduced by 100%. However, barley bran had significantly higher mycotoxin concentrations than the pre-milled grains: bran from hulled barley had a 357% increase in deoxynivalenol, 252% increase in nivalenol, and 169% increase in zearalenone. Similarly, bran from naked barley had a 337% increase in deoxynivalenol, 239% increase in nivalenol, and 554% increase in zearalenone. These results show that mycotoxins present in the outer layers of barley grain can be effectively removed through the milling process. As milling redistributes mycotoxins from the grain into the bran, however, it shows that advance monitoring of barley bran is recommended when using barley bran for human or animal consumption.

• Korean Journal of Heritage: History & Science
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• v.57 no.1
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• pp.146-159
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• 2024

In this study, a study on the production technology of the Buddha statue and the production of raw material origin was conducted through scientific analysis on the Bronze seated Bodhisattva Statue of Goseongsa Temple, a treasure. As a result of microstructure analysis through a metal microscope, it was confirmed that the microstructure of the Bronze seated Bodhisattva Statue of Goseongsa Temple was a process-type dendritic structure, and the casting structure of bronze was well represented, so it was manufactured through casting. Subsequently, as a result of analyzing the alloy composition ratio through SEM-EDS, it was identified as a ternary alloy with 81.26 wt% of copper (Cu) and 16.42 wt% of tin (Sn) and 1.72 wt% of lead (Pb). The results of the analysis of lead isotope ratios using a thermal ionization mass spectrometer (TIMS) were substituted into the distribution of lead isotope ratios on the Korean Peninsula, it was shown in corresponding to Jeolla-do and Chungcheong-do regions and North and South Gyeongsang Province. This suggests that the raw materials used in their production were likely sourced from the mines around Goseong Temple in Gangjin. Despite the fact that the statue is a medium and large Buddha with a total height of 51 centimeters, 1.72 wt% of lead (Pb) was found as a result of alloy composition ratio analysis, which showed a similar composition to the lead content ratio of small bronze and gilt-bronze Buddha statues. Therefore, we compared and analyzed the results of the analysis of the composition ratio of the alloys of bronze and gilt bronze statues, which has been scientifically analyzed with a compositional age similar to that of the Bronze seated Bodhisattva Statue of Goseongsa Temple. Comparison results, Various factors, such as the size of the Buddha statue as well as its stylistic characteristics and the age of composition, may exist in determining the alloy composition ratio of the bronze and gilt bronze Buddha statues, and it was confirmed that the alloy composition ratio or casting technology was properly adjusted when the Buddha statue was created. In other words, it is judged that a more comprehensive system of Buddha statue production technology should be investigated by conducting archaeological and art history studies on stylistic characteristics and age of composition, as well as scientific analysis results such as observation of internal structure, microstructure observation, and analysis of alloy composition ratio using radiation transmission irradiation.

• Korean Journal of Heritage: History & Science
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• v.57 no.3
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• pp.6-22
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• 2024

This paper examines the characteristics of wooden wells from the Three Kingdoms period that were discovered in the Yeongsan River basin, in addition to their functions based on the distribution of the remains and excavated artifacts found near the wells. A total of 11 wooden wells have been found at six archeological sites along the middle and upper reaches of the Yeongsan River basin. These wooden wells were built in a wider variety of forms than wells made of other materials due to the ease of processing resulting from the physical properties of wood. However, due to the limited geological conditions in which these wells can be installed and their rapid decay, the discovery of such wells is rare. They tend to be located in the clay and mud layers of old river channels or near river channels where it was relatively easy to obtain water from the riverbed. The wooden wells are mostly square or rectangular in shape and were assembled transversely, and some include support beams in their construction. The backfill was reinforced with either stone, a mixture of stone and clay, or a mixture of clay and pottery shards. The material mainly used was pine wood boards, with wood from chestnut trees being used as a sub-material. Various artifacts, such as pottery and wooden containers, animal bones, and seeds, have been excavated in small quantities. The excavated pottery items consist mostly of flat cups with a cover, mounted cups, pottery stands, wide-mouthed jars with a hole, and round pottery. Based on the environment and remains of the sites, the wells are thought to have been used for domestic and production purposes. The assumed primary function was to obtain domestic water, as most of the wells were located within residential spaces where the area's inhabitants lived. The wells were also used to obtain water for agricultural purposes, as well as for productive purposes such as for operating kilns and smelters. Lastly, the wooden wells were also found to be strongly associated with rites, as evidenced by the artifacts found inside them.

• Economic and Environmental Geology
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• v.57 no.4
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• pp.397-416
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• 2024

This study assessed the hydrogeological properties of the deep geological environment to develop safety criteria for the natural barriers used in the deep geological disposal of high-level radioactive waste in Korea. The assessment focused on the distribution and trends of hydraulic conductivity and permeability properties appropriate for the domestic geological environment, using various in-situ hydraulic test data collected for groundwater development and management. To develop a depth-hydrogeological property relationship model suitable for domestic conditions, the study reviewed various international research examples and applied a representative model that explains the trends of hydraulic conductivity and permeability with depth. The development of the model suitable for Korea involved applying ensemble regression analysis to account for the uncertainty of various factors in the collected data. The results confirmed that existing international depth-hydrogeological property relationship models adequately describe the characteristics of the domestic geological environment. Considering the preferred hydrogeological criteria suggested by countries like Sweden, Germany, and Canada, there is a high likelihood that a suitable geological environment exists in Korea. Additionally, the application of hydrogeological criteria indicative of low-permeability environments showed that suitable conditions for disposal construction increase at depths greater than 300 m, where the influence of fractures on groundwater flow might be minimal at depths exceeding 500 m. This research can serve as foundational information for establishing hydrogeological safety standards for natural barriers in Korea according to international regulatory guidelines.

• Resources Recycling
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• v.33 no.4
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• pp.47-61
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• 2024

As a recycling technology for recovering zinc contained in large amounts in electric arc furnace dust (EAFD), the most commercialized technology in the world is the Wealz Kiln Process. The Wealz Kiln Process is a process in which components such as Zn and Pb in EAFD are reduced/volatile (endothermic reaction) in high-temperature Kiln and then re-oxidized (exothermic reaction) in the gas phase and recovered in the form of Crude zinc oxide (60wt%Zn) in the Bag Filter installed at the rear end of Kiln. In this study, an experimental Wealz kiln was produced to investigate the optimal process variable value for practical application to the recycling process of large-scale kiln on a commercial scale. Additionally, Pellets containing EAFD, reducing agents, and limestone were continuously loaded into Kiln, and the amount of input, heating temperature, and residence time were examined to obtain the optimal crude zinc oxide recovery rate. In addition, the optimal manufacturing conditions of Pellets (drum tilt angle, moisture addition, mixing time, etc.) were also investigated. In addition, referring to the SiO₂-CaO-FeO ternary system diagram, the formation behavior of a low melting point compound, a reaction product inside Kiln according to the change in the basicity of Pellet, and the reactivity (adhesion) with the castable constructed on the inner wall of Kiln were investigated. In addition, in order to quantitatively investigate the possibility of using anthracite as a substitute for Coke, a reducing agent, changes in the temperature distribution inside Kiln, where oxidation/reduction reactions occur due to an increase in the amount of anthracite, the quality of Crude zinc oxide, and the behavior of tar in anthracite were also investigated.

• 유학연구
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• v.48
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• pp.129-171
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• 2019

The purpose of this study is to collect, to classify education archives of Joseon Seowon, and to examine characteristics of education archives. The subjects of this study are Sosu-Seowon, Dosan-Seowon, Dodong-Seowon, Oksan-Seowon, Donam-Seowon. According to the contents and nature of the archives, I divided educational archives into four types: the record of rules of Seowon education, the record of actual education, the record of ritual, and the record of financial. First, through the record of rules, I have identified how the rules are passed down and changed from Seowon to Seowon and impact of book publishing and distribution on changes in Seowon Curriculum. Secondly, through the record of educational practice, I have examined the size of students participating in Seowon education, the role of officers, the procedures and methods of education, the daily routine in Seowon, the methods of discussion and questions in lectures, and the role of teachers in discussions etc. Third, through the record of rituals, I examined customary rituals such as Gyeongdok(敬 讀), the rites for opening class(開接禮) and the last class(罷接禮), and the rites for Master-Disciple Relationshipe(贄禮) in addition to official rites such as Jeongeuprye(庭揖 禮) and Sangeuprye(相揖禮). Fourth, through the record of financial, we could see howthe late Joseon Seowon tried to continue the education by setting up a financial institution dedicated to education despite severe financial difficulties. The classification criteria and the typification method of education archives of Joseon Seowon that have been attempted in this study can be used as a model for systematically collecting and organizing the education archives of Joseon Seowon. However, this needs to be supplemented and discussed further. In addition, if a methodology can be developed to collect a wide range of materials that have been scattered over various materials through the classification and typification of the materials, it will contribute to expanding the horizon of Seowon research in the future