• Journal of Korean Society of Forest Science
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• v.110 no.2
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• pp.217-232
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• 2021

This study calculated the productivity and cost of extraction and processing of logging residues by cut-to-length (CTL) and whole-tree (WT) harvesting methods. In addition, the comparative analysis of the characteristics of wood chip fuel to examine whether it was suitable for the fuel conditions of the energy facility. In the harvesting and processing system to produce the wood chips of logging residues the system productivity and cost of the CTL harvesting system were 1.6 Gwt/SMH and 89,865 won/Gwt, respectively. The productivity and cost of the WT harvesting system were 2.9 Gwt/SMH and 72,974 won/Gwt, respectively. The WT harvesting productivity increased 1.3times while harvesting cost decreased by 18.7% compared to the CTL harvesting system. The logging residues of wood chips were not suitable for CTL wood chips based on International Organization for Standardization (ISO 17225-4:2021) and South Korea standard (NIFoS, 2020), but the quality (A2, Second class) was improved through screening operation. The WT-unscreened wood chips conformed to NIFoS standard (second class) and did not conform to ISO but were improved through screening operation (Second class). In addition to the energy facility in plant A, all wood chips except CTL-unscreened wood chips were available through drying processing. The WT-unscreened wood chips were the lowest at 99,408 won/Gwt. Plants B, C, and D had higher moisture content than plant A, so WT-unscreened wood chips without drying processing were the lowest at 57,204 won/Gwt. Therefore, the production of logging residues should improve with operation methods that improve the quality of wood chips required for applying the variable biomass and energy facility.

• Economic and Environmental Geology
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• v.54 no.4
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• pp.409-425
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• 2021

Carbon dioxide has been known to be a typical greenhouse gas causing global warming, and a number of efforts have been proposed to reduce its concentration in the atmosphere. Among them, carbon dioxide capture and storage (CCS) has been taken into great account to accomplish the target reduction of carbon dioxide. In order to commercialize the CCS, its safety should be secured. In particular, if the stored carbon dioxide is leaked in the arable land, serious problems could come up in terms of crop growth. This study was conducted to investigate the effect of carbon dioxide leaked from storage sites on soil fertility. The leakage of carbon dioxide was simulated using the facility of its artificial injection into soils in the laboratory. Several soil chemical properties, such as pH, cation exchange capacity, electrical conductivity, the concentrations of exchangeable cations, nitrogen (N) (total-N, nitrate-N, and ammonia-N), phosphorus (P) (total-P and available-P), sulfur (S) (total-S and available-S), available-boron (B), and the contents of soil organic matter, were monitored as indicators of soil fertility during the period of artificial injection of carbon dioxide. Two kinds of soils, such as non-cultivated and cultivated soils, were compared in the artificial injection tests, and the latter included maize- and soybean-cultivated soils. The non-cultivated soil (NCS) was sandy soil of 42.6% porosity, the maize-cultivated soil (MCS) and soybean-cultivated soil (SCS) were loamy sand having 46.8% and 48.0% of porosities, respectively. The artificial injection facility had six columns: one was for the control without carbon dioxide injection, and the other five columns were used for the injections tests. Total injection periods for NCS and MCS/SCS were 60 and 70 days, respectively, and artificial rainfall events were simulated using one pore volume after the 12-day injection for the NCS and the 14-day injection for the MCS/SCS. After each rainfall event, the soil fertility indicators were measured for soil and leachate solution, and they were compared before and after the injection of carbon dioxide. The results indicate that the residual concentrations of exchangeable cations, total-N, total-P, the content of soil organic matter, and electrical conductivity were not likely to be affected by the injection of carbon dioxide. However, the residual concentrations of nitrate-N, ammonia-N, available-P, available-S, and available-B tended to decrease after the carbon dioxide injection, indicating that soil fertility might be reduced. Meanwhile, soil pH did not seem to be influenced due to the buffering capacity of soils, but it is speculated that a long-term leakage of carbon dioxide might bring about soil acidification.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.47 no.2
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• pp.155-161
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• 2021

This study was attempted to investigate natural materials with antimicrobial activity and to apply as natural preservatives in cosmetics. The disc diffusion method was used to search for nine species of natural antibacterial material for three species of skin pathogenic bacteria (Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa) and Candida albicans. As a result of measuring the size of inhibition zone, Rhus Semialata gall (Gallnut) extract, Oak vinegar, and ε-polylysine were showed strongest antibacterial activities (> 10 mm). The Minimum Bactericidal Concentration (MBC) of gallnut and oak vinegar ranged from 10 to 20 mg/mL and from 20 to 40 mg/mL against five human skin pathogens. The MBC of ε-polylysine ranged from 0.5 to 2 mg/mL in fungus. The synergic effect of gallnut extract/oak vinegar mixture and gallnut extract/ε-polylysine mixture were evaluated by checkerboard test. Compared to when used alone, the MBC of gallnut extract/oak vinegar mixture were at 4 times lower concentration against E. coli, C. albicans, and A. brasiliensis. Also Furthermore, the MBC of gallnut extract/ε-polylysine mixture were at 4 times lower concentration against C. albicans and A. brasiliensis. It was confirmed that the combination of gallnut extract with oak vinegar or ε-polylysine resulted in synergistic antibacterial effect against three human skin pathogens. Thus, it is expected that gallnut extract and natural product mixture can not only demonstrate antibacterial synergies, but also be applied in cosmetics as a natural preservative system with a wide antibacterial spectrum.

• The Korean Journal of Nuclear Medicine Technology
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• v.25 no.1
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• pp.21-28
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• 2021

Purpose Brown fat, or brown adipose tissue (BAT), is involved in non-shivering thermogenesis and creates heat through glucose metabolism. BAT activation occurs stochastically by internal factors such as age, sex, and body mass index (BMI) and external factors such as temperature and environment. In this study, as a retrospective, electronic medical record (EMR) observation study, statistical analysis is conducted to confirm BAT activation and various factors. Materials and Methods From January 2018 to December 2019, EMR of patients who underwent PET/CT scan at the National Cancer Center for two years were collected, a total of 9155 patients were extracted, and 13442 case data including duplicate scan were targeted. After performing a univariable logistic regression analysis to determine whether BAT activation is affected by the environment (outdoor temperature) and the patient's condition (BMI, cancer type, sex, and age), A multivariable regression model that affects BAT activation was finally analyzed by selecting univariable factors with P<0.1. Results BAT activation occurred in 93 cases (0.7%). According to the results of univariable logistic regression analysis, the likelihood of BAT activation was increased in patients under 50 years old (P<0.001), in females (P<0.001), in lower outdoor temperature below 14.5℃ (P<0.001), in lower BMI (P<0.001) and in patients who had a injection before 12:30 PM (P<0.001). It decreased in higher BMI (P<0.001) and in patients diagnosed with lung cancer (P<0.05) In multivariable results, BAT activation was significantly increased in patients under 50 years (P<0.001), in females (P<0.001) and in lower outdoor temperature below 14.5℃ (P<0.001). It was significantly decreased in higher BMI (P<0.05). Conclusion A retrospective study of factors affecting BAT activation in patients who underwent PET/CT scan for 2 years at the National Cancer Center was conducted. The results confirmed that BAT was significantly activated in normal-weight women under 50 years old who underwent PET/CT scan in weather with an outdoor temperature of less than 14.5℃. Based on this result, the patient applied to the factor can be identified in advance, and it is thought that it will help to reduce BAT activation through several studies in the future.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.93-99
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• 2022

With the rapid development of ultra-small and wearable device technology, continuous electricity supply without spatiotemporal limitations for driving electronic devices is required. Accordingly, Triboelectric nanogenerator (TENG), which utilizes static electricity generated by the contact and separation of two different materials, is being used as a means of effectively harvesting various types of energy dispersed without complex processes and designs due to its simple principle. However, to apply the TENG to real life, it is necessary to increase the electrical output. In addition, stable generation of electrical output, as well as increase in electrical output, is a task to be solved for the commercialization of TENG. In this study, we proposed a method to not only improve the output of TENG but also to stably represent the improved output. This was solved by using the contact layer, which is one of the components of TENG, as an electret for improved output and stability. The utilized electret was manufactured by sequentially performing corona charging-thermal annealing-corona charging on the Fluorinated ethylene propylene (FEP) film. Electric charges artificially injected due to corona charging enter a deep trap through the thermal annealing, so an electret that minimizes charge escape was fabricated and used in TENG. The output performance of the manufactured electret was verified by measuring the voltage output of the TENG in vertical contact separation mode, and the electret treated to the corona charging showed an output voltage 12 times higher than that of the pristine FEP film. The time and humidity stability of the electret was confirmed by measuring the output voltage of the TENG after exposing the electret to a general external environment and extreme humidity environment. In addition, it was shown that it can be applied to real-life by operating the LED by applying an electret to the clap-TENG with the motif of clap.

• Journal of Korean Society of Forest Science
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• v.111 no.1
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• pp.61-71
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• 2022

Data from an investigation of vulnerable conifer species in the subalpine zone in Korea obtained by the Korea Forest Service in 2017-2018 and monitoring research conducted by the National Institute of Forest Science since 2014 were used to analyze the status of distribution and growing condition of three major conifer species (Abies nephrolepis, Abies koreana, and Picea jezoensis) in the subalpine zone in the Baekdudaegan protected area. The distribution area of the studied species in the Baekdudaegan protected area was ca. 74% (8,035 ha) of the total distribution area in Korea, indicating that Baekdudaegan is a core area for conservation and restoration of subalpine conifer species. From decline index [A. nephrolepis in Mt. Taebaeksan and Mt. Deogyusan increased by 77.3% and 29.6%, respectively; A. koreana in Mt. Jirisan (Chunwangbong Peak) increased by 45.2% in four years; and P. jezoensis in Mt. Jirisan (Chunwangbong Peak) increased by 47.8% in two years] and seedling frequency (lower frequency of newly recruited seedlings than dead seedlings) results, the studied species are expected to face difficulties in sustainability. In contrast, at Mt. Seseoksan and Chunwangbong Peak in Mt. Jirisan, the health of trees and seedling frequency showed a partial tendency to recover and increase. In addition, we identified the relationship between the decline index and seedling frequency. These results will support the implementation of conservation strategies for vulnerable conifer species in the subalpine zone.

• Microbiology and Biotechnology Letters
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• v.49 no.4
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• pp.552-558
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• 2021

Traditional foods are manufactured according to the characteristics of each region for the nations of the world. Korea has mainly farmed, and seasonings have developed around rice and vegetables. In fermented foods, lactic acid bacteria such as Lactobacillus sp. and Pediococcus sp. and Bacillus sp. were isolated and identified from fermented foods. In this study, lactic acid bacteria were isolated and identified from commercially available traditional Korean fermented foods, and candidate strains were selected through antibacterial activity tests on human and fish disease bacteria. Thereafter, the final strain was selected by examining the resistance to simulated gastric and intestinal fluids, and hemolysis. The three (M1, K1, C13) final selected latic acid bacteria were miced with prebiotics and the antibacterial activity of synbiotics was evaluated. As for the fist antibacterial activity result, C13 showed high antibacterial acitivity in human diseases and fish diseases. Then, M1, K1 and C13, which did not produce β-haemolysis and were resistant to simulated gastric and intestinal fluids, were subjected to the second antibacterial activity of synbiotics. When the three prebiotics (FOS, GOS, Inulin) and probiotics (M1, K1, C13) were mixed, the antibacterial activity was increased or inhibited. Based on the 16S rRNA gene sequencing results, K1 and M1 were analyzed as Bacillus tequiensis 99.72%, Bacillus subtilis 99.65%, Bacillus inaquosorum 99.72%, Bacillus cabrialesii 99.72%, Bacillus stercoris 99.58%, Bacillus spizizenii 99.58%, Bacillus halotolerans 99.58%, and Bacillus mojavensis 99.51%. And C13 was analyzed as Bacillus velezensis 99.71%, Bacillus nematocida 99.36%, Bacillus amyloliquefaciens 99.44%, Bacillus atrophaeus 99.22%, and Bacillus nakamurai 99.44%.

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.4
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• pp.198-221
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• 2021

After large-scale reforestation in the 1960s and 1970s, forests in Korea have gradually been aging. Net ecosystem CO₂ exchange of old-growth forests is theoretically near zero; however, it can be a CO₂ sink or source depending on the intervention of disturbance or management. In this study, we report the CO₂ budget dynamics of the Gwangneung deciduous old-growth forest (GDK) in Korea and examined the following two questions: (1) is the preserved GDK indeed CO₂ neutral as theoretically known? and (2) can we explain the dynamics of CO₂ budget by the common mechanisms reported in the literature? To answer, we analyzed the 15-year long CO₂ flux data measured by eddy covariance technique along with other biometeorological data at the KoFlux GDK site from 2006 to 2020. The results showed that (1) GDK switched back-and-forth between sink and source of CO₂ but averaged to be a week CO₂ source (and turning to a moderate CO₂ source for the recent five years) and (2) the interannual variability of solar radiation, growing season length, and leaf area index showed a positive correlation with that of gross primary production (GPP) (R²=0.32~0.45); whereas the interannual variability of both air and surface temperature was not significantly correlated with that of ecosystem respiration (RE). Furthermore, the machine learning-based model trained using the dataset of early monitoring period (first 10 years) failed to reproduce the observed interannual variations of GPP and RE for the recent five years. Biomass data analysis suggests that carbon emissions from coarse woody debris may have contributed partly to the conversion to a moderate CO₂ source. To properly understand and interpret the long-term CO₂ budget dynamics of GDK, new framework of analysis and modeling based on complex systems science is needed. Also, it is important to maintain the flux monitoring and data quality along with the monitoring of coarse woody debris and disturbances.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.66 no.4
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• pp.339-349
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• 2021

In recent years, the occurrence of bacterial diseases of soybean has been increasing due to the continuous rise in spring temperature and the humid weather as a result of rain concentrated at the middle and late stages of crop growth. The resulting severe economic damage is also a concern. Unfortunately, there are no precise data on the occurrence and damage to lay the foundation for bacterial disease control in soybean in the Chungbuk Province. Therefore, the present study investigated the occurrence of major bacterial diseases, namely bacterial pustules, bacterial blight, and wildfire, in different soybean varieties in 410 fields in the Chungbuk Province in 2017. The incidence rate of bacterial pustules in the affected fields was 76.6%, and the incidence rate of infected plants was 29.3%. The incidence rate of bacterial blight in the affected fields was 13.9%, and the incidence rate of infected plants was 4.6%. The incidence rate of wildfire in the affected fields was 23.2%, and the incidence rate of infected plants was 10.1%. The overall incidence rate of bacterial diseases in the soybean fields where the diseases originated was 37.9% for bacterial pustules, 21.0% for bacterial blight, and 25.0% for wildfire, indicating that the disease incidence rate in fields where the disease originated was generally high. Among different varieties, the incidence rate of bacterial pustules was the highest in sprout soybean (88.9%), followed by Seoritae (84.0%) and Daewon (81.2%). The incidence rate of bacterial blight was the highest in the Daewon (19.6%), followed by Seoritae (15.2%) and sprout soybean (12.5%). The incidence rate of wildfire was the highest in sprout soybean (25.0%), followed by Daewon (24.7%) and Seoritae (5.4%). Meanwhile, in Uram, the incidence rate of bacterial pustules (7.1%) was the lowest, and this variety was not affected by bacterial blight or wildfire.

• Clean Technology
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• v.28 no.1
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• pp.24-31
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• 2022

Petroleum-based plastics are used for various purposes and pose a significant threat to the earth's environment and ecosystem. Many efforts have been taken globally in different areas to find alternatives. As part of these efforts, this study manufactured alginate-based polyvinyl alcohol (PVA) blended films by casting from an aqueous solution prepared by mixing 10 wt% petroleum-based PVA with biodegradable, marine biomass-derived alginate. Glutaraldehyde was used as a cross-linking agent, and cardanol, an alkyl phenol-based bio-oil extracted from cashew nut shell, was added in the range of 0.1 to 2.0 wt% to grant antibacterial activity to the films. FTIR and TGA were performed to characterize the manufactured blended films, and the tensile strength, degree of swelling, and antibacterial activity were measured. Results obtained from the FTIR, TGA, and tensile strength test showed that alginate, the main component, was well distributed in the PVA by forming a matrix phase. The brittleness of alginate, a known weakness as a single component, and the low thermal durability of PVA were improved by cross-linking and hydrogen bonding of the functional groups between alginate and PVA. Addition of cardanol to the alginate-based PVA blend significantly improved the antibacterial activity against S. aureus and E. coli. The antibacterial performance was excellent with a death rate of 98% or higher for S. aureus and about 70% for E. coli at a contact time of 60 minutes. The optimal antibacterial activity of the alginate-PVA blended films was found with a cardanol content range between 0.1 to 0.5 wt%. These results show that cardanol-containing alginate-PVA blended films are suitable for use as various antibacterial materials, including as food packaging.