• Journal of Food Hygiene and Safety
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• v.36 no.6
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• pp.474-480
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• 2021

Sodium alginate is the sodium salt of alginic acid, commonly used as a food additive for stabilizing, thickening, and emulsifying properties. A relatively simple and universal analysis method is used to study sodium alginate due to the complex pretreatment process and extended analysis time required during the quantitative method. As for the equipment, HPLC-UVD and Unison US-Phenyl column were used for analysis. For the pretreatment condition, a shaking apparatus was used for extraction at 150 rpm for 180 minutes at room temperature. The calibration curve made from the standard sodium alginate solution in 5 concentration ranges showed that the linearity (R²) is 0.9999 on average. LOD and LOQ showed 3.96 mg/kg and 12.0 mg/kg, respectively. Furthermore, the average intraday and inter-day accuracy (%) and precision (RSD%) were 98.47-103.74% and 1.69-3.08% for seaweed jelly noodle samples and 99.95-105.76% and 0.59-3.63% for sherbet samples, respectively. The relative uncertainty value was appropriate for the CODEX standard with 1.5-7.9%. To evaluate the applicability of the method developed in this study, the sodium alginate concentrations of 103 products were quantified. The result showed that the detection rate is highest from starch vermicelli and instant fried noodles to sugar processed products.

• Journal of the Korean earth science society
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• v.43 no.3
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• pp.386-404
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• 2022

From April 29 to 30, 2011, under the influence of Asian dust originated from Mongolia, a high concentration of Asian dust was observed nationwide for 4 days in Korea. This study investigated the causes and characteristics of and weather conditions associated with Asian dust at high concentrations at its source in Mongolia. For analysis, Asian dust weather data, Asian dust monitoring tower data, satellite data, backward trajectory data, observation data (PM₁₀ and OPC data), and ECMWF reanalysis data were used. In the synoptic analysis, it was observed that the intervals of isobars were densely distributed in the central region of Mongolia and the pressure gradient force was strong. It could be inferenced that Asian dust occurred due to strong winds. The temperature was relatively high, above 10℃, just before the occurrence of Asian dust, and it decreased sharply at the onset of the dust. The relative humidity had a low value of less than approximately 40%. After the occurrence of Asian dust, it increased sharply to over 50% and then showed a tendency to decrease. In the aerosol index shown by the COMS satellite, a high concentration value of over 25 was detected in Inner Mongolia, and it was consistent with the observations made with naked eyes. In the 72-hour backward trajectory, the northwest airflow streamed into Korea, and on May 2, Heuksando showed the highest PM₁₀ concentration of 1,025 ㎍ m^-3(times the average). Especially, in kinematic vertical analysis, it was observed that low pressure on the ground was strengthened by cyclonic relative vorticity developed in the upper layer. Also, the vertical velocity development is considered to have played a major role in the occurrence of high concentration Asian dust.

• Journal of Practical Agriculture & Fisheries Research
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• v.23 no.2
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• pp.15-24
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• 2021

For the aquaculture industrialization of surf clam (Tresus keenae), it is important to basic data on the marine environment of the habitat of surf clam (T. keenae). In this study, we investigated the marine environment of habitat of surf clam (T. keenae) and sought to basic data for the preparation of surf clam (T. keenae) for artificial seed production. The water temperature of the habitat of surf clam (T. keenae) was the lowest in winter and appeared high in summer. The salt concentration showed it range from 31.2 to 33.9 psu. The pH showed it range from 7.69 to 8.70, with high pH in winter and low pH in summer. The dissolved oxygen(DO) was showed it range from 6.20 to 10.24 mg / L and the autumn was relatively higher than the spring and winter. The species composition of phytoplankton was about 30 to 40 species, and most of them were diatoms. The abundance of seasonal phytoplankton showed it range from 23.5 to 61.3 cells / ml, showing seasonal differences. The expression of dominant species also showed a difference depending on the season. As for the particle size composition of the sediment, sandy silt was the most distributed. Flow velocities appeared at 50-80 cm / s in the southeast direction at ebb tide and at 60-100 cm / s in the northwest direction at flood tide. The results of this study can be used as basic data for providing knowledge about the habitat and marine environment of surf clam (T. keenae) and for studying shellfish that inhabit the sedimentary layer.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.4
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• pp.639-647
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• 2022

The use of flames is essential in cutting, bending, and welding steel during a ship's construction process. While acetylene fuel is commonly used in steel cutting and the manufacturing process in shipyards, the use of propane as an alternative fuel has recently been increasing, due to the lower risk of explosion and propane's relatively low calorific value. However, propane fuel has a relatively slow processing speed and high slag generation frequency, thereby resulting in poor quality. Propylene is another alternative fuel, which has an excellent calorific value. It is expected to gain wider use because of its potential to improve the quality, productivity, and efficiency of steel processing. In this study, the combustion characteristics of propane and propylene fuel during steel plate processing were analyzed and compared. The reduction of greenhouse gases and other harmful gases when using propylene flame was experimentally verified by analyzing the gases emitted during the process. Heat distribution and tensile tests were also performed to investigate the effects of heat input, according to processing fuel used, on the mechanical strength of the marine steel. The results showed that when propylene was used, the temperature was more evenly distributed than when propane fuel was used. Moreover, the mechanical tests showed that when using propylene, there was no decrease in tensile strength, but the strain showed a tendency to decrease. Based on the study results, it is recommended that propylene be used in steel processing and the cutting process in actual shipyards in the future. Additionally, more analysis and supplementary research should be conducted on problems that may occur.

• Korean Journal of Ecology and Environment
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• v.54 no.4
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• pp.384-389
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• 2021

This study was conducted on October 23, 2020 at the Cheongpyeong Reservoir located in Seorakmyeon, Gapyeong-gun, Gyeonggi-do, and analyzed the horizontal and vertical distribution patterns of fish based on data obtained using fishfinder. The total surface area of fishfinder survey conducted was 782,853 m², and where the water depth (WD) ranges from 10 m to 12 m is widest which 31.7% of total surface area. As a result of the heat map analysis, fish density was highest at right bank under the Gapyeong-bridge, but there was no specific pattern in horizontal distribution of fish. As a result of vertical distribution of fish analysis, 86.6% of fishes are observed at below 6 m of the fish depth (FD, distance from water surface to fish). As a result of the relative height (RH, water depth-distance from bottom to fish ratio) analysis, there was a tendency that fishes are distributed in near surface area more as the WD increased. This tendency could have various reasons such as water temperature gradient along the water depth, and further studies are required for detailed explanation.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.28 no.2
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• pp.133-142
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• 2022

Korean enoki mushrooms are exported to Southeast Asia and the United States, where there are complaints due to quality deterioration during the distribution process. In this study, we evaluated the efficacy of vacuum film packaging on quality maintenance in Korean enoki mushrooms during simulated vessel export to Vietnam using selected film, which was developed with vacuum packaging machine and oxygen absorber. We selected two MA film, one was 2-layerd 30 ㎛ CPP film (control) and the other was 3-layered 30 ㎛ CPP film (treatment) which is optimized film of higher gas and moisture permeability. The Korean enoki mushrooms were packaged with these two films using PAC-2000 or PAC-3000 vacuum packaging machine which was improved vacuuming of higher speed. Packed mushrooms were stored at 1℃ for 2 weeks and distributed at 20℃ for 2 days or 8℃ for 6 days. The efficiency of the film packaging was analyzed by vacuum maintaining index, and overall the quality characteristics such as off odor, color, cap cleavage, stem elongations and sensory evaluation were evaluated during storage and distribution. Results suggest that postharvest loss of fresh enoki mushroom could be reduced by packaging mushroom with 3-layered 30 ㎛ CPP films packaged using PAC-3000 machine during simulated vessel export to Vietnam due to vacuum maintaining. Oxygen absorber promoted off-odor at 20℃ distribution temperature, and did not affect storability at 1℃ storage compared to treated group without oxygen absorber treatment.

• Journal of Life Science
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• v.32 no.8
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• pp.641-646
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• 2022

There are concerns about the environmental release of living modified organism (LMO) maize created to increase yields. In fact, there are cases in which LMO crops for feed have been leaked in Korea to form autoite colonies, and concerns about LMO spill are intensifying. In this study, the possibility of environmental outflow and occurrence of native organisms was analyzed using maize feed and seeds distributed in Korea. In the evaluation of the possibility of spontaneous occurrence of maize in the event of an unintentional release of maize feed made by crushing maize, the incidence rate of maize was 0.01%, which was extremely low compared to the germination rate of maize seeds. A survey of the dormant rate of maize showed that all maize seeds collected every month were dead. In the germination rate test by temperature using Daehak wax corn and Kwangpyeongok, high germination rates were found at 20℃ and 30℃, and relatively low germination rates were found at 10℃ and 40℃. In addition, all germination tests showed a higher germination rate Daehak wax corn than Kwangpyeongok. The difference between domestic and overseas cultivation maize was confirmed through a survey on the agricultural properties of three varieties of maize. The data obtained through this experiment could be the basis for the evaluation of the weediness potential of environmental risk assessment and technology to suppress the occurrence of autoite in preparation for future LMO spills.

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.78-78
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• 2002

The role of heat shock proteins in shielding organism from environmental stress is illustrated by the large-scale synthesis of these protein by the organism studied to date. However, recent evidence also suggests an important role for heat shock protein in fertilization and early development of mammalian embryos. Effects of elevated in vitro temperature on in vitro produced bovine embryos were analysed in order to determine its impact on the expression of heat shock protein 70 (HSP70) by control and frozen-thawed after in vitro fertilization (IVF) or nuclear transfer (NT). The objective of this study was to assess the developmental potential in vitro produced embryos with using of the various containers and examined expression and localization of heat shock protein 70 after it's frozen -thawed. For the vitrification, in vitro produced embryos at 2 cell, 8 cell and blastocysts stage after IVF and NT were exposed the ethylene glycol 5.5 M freezing solution (EG 5.5) for 30 sec, loaded on each containers such EM grid, straw and cryo-loop and then immediately plunged into liquid nitrogen. Thawed embryos were serially diluted in sucrose solution, each for 1 min, and cultured in CRI-aa medium. Survival rates of the vitrification production were assessed by re-expanded, hatched blastocysts. There were no differences in the survival rates of IVF using EM grid, cryo-loop. However, survival rates by straw were relatively lower than other containers. Only, nuclear transferred embryos survived by using cryo-loop. After IVF or NT, in vitro matured bovine embryos 2 cell, 8 cell and blastocysts subjected to control and thawed conditions were analysed by semiquantitive reverse transcription polymerase chain reaction methods for hsp 70 mRNA expression. Results revealed the expression of hsp 70 mRNA were higher thawed embryos than control embryos. Immunocytochemistry used to localization the hsp70 protein in embryos. Two, 8-cell embryos derived under control condition was evenly distributed in the cytoplasm but appeared as aggregates in some embryos exposed frozen-thawed. However, under control condition, blastocysts displayed aggregate signal while Hsp70 in frozen-thawed blastocysts appeared to be more uniform in distribution.

• Journal of the Korean Geotechnical Society
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• v.23 no.11
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• pp.87-98
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• 2007

For the quick rehabilitation of a fire-damaged tunnel structure, it is the most important procedure to investigate the fire-induced damaged zone rapidly. This study aims to propose a new drilling resistance testing method by which mechanical properties of tunnel concrete lining altered by high temperature can be estimated easily and continuously. Especially, it alms to derive the relationships to estimate mechanical properties of mortar and concrete materials from drilling parameters. To obtain the optimum testing condition, a series of drilling resistance tests were carried out for mortar specimens. When the rotation per minute of drill bit, tile penetration rate and the bit diameter were 1,300 rpm, 1.40 mm/sec, and 10 mm respectively, the deviation of measured drilling resistance forces was minimal. Under the optimum testing condition, the relationships between drilling resistance and mechanical properties of mortar specimens were shown to be very favorable. The concept of replacing a mean value of resistance farces measured during drilling with the resistance energy was proposed to consider the effects of randomly distributed aggregates inside a concrete material on drilling resistance. When the concept was applied to concrete materials, a favorable relationship between actual compressive strength and drilling resistance energy was also successfully derived.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2B
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• pp.107-120
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• 2010

The effect of potential future climate change on the inflow of agricultural reservoir and its impact to downstream streamflow by reservoir operation for paddy irrigation water was assessed using the SLURP (semi-distributed land use-based runoff process), a physically based hydrological model. The fundamental input data (elevation, meteorological data, land use, soil, vegetation) was collected to calibrate and validate of the SLURP model for a 366.5 $km^2$ watershed including two agricultural reservoirs (Geumgwang and Gosam) located in Anseongcheon watershed. Then, the CCCma CGCM2 data by SRES (special report on emissions scenarios) A2 and B2 scenarios of the IPCC (intergovernmental panel on climate change) was used to assess the future potential climate change. The future weather data for the year, m ms, m5ms and 2amms was downscaled by Change Factor method through bias-correction using 3m years (1977-2006) weather data of 3 meteorological stations of the watershed. In addition, the future land uses were predicted by modified CA (cellular automata)-Markov technique using the time series land use data fromFactosat images. Also the future vegetation cover information was predicted and considered by the linear regression between monthly NDVI (normalized difference vegetation index) from NOAA AVHRR images and monthly mean temperature using eight years (1998-2006) data.