• Nuclear Engineering and Technology
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• v.48 no.2
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• pp.293-298
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• 2016

Thirty-eight spherules from the Antarctic ice sheet were analyzed using neutron activation analysis under two different conditions to investigate their origin. In almost all of these spherules, the contents of iron, cobalt, and manganese were determined to be 31% to 88%, 17 mg/kg to 810 mg/kg, and 0.017% to 7%, respectively. A detectable iridium content of 0.84 mg/kg was found in only one spherule, which was judged to be extraterrestrial in origin. A comparison of elemental compositions of the Antarctic spherules analyzed in this study with those of deep-sea sediment spherules and those of terrestrial materials revealed that most of the Antarctic spherules except for the sample in which iridium was detected could not be identified as extraterrestrial in origin.

• Journal of the Korean Geosynthetics Society
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• v.12 no.3
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• pp.23-29
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• 2013

The mechanical behavior of frozen soils is different from that of unfrozen soils due to the phase change between water and ice. The strength characteristics of frozen soils are governed by the intrinsic material properties such as grain size, ice and water content, air bubbles, and by externally imposed testing conditions such as temperature, freezing time, and strain rate. Especially, the strength of the frozen soils is generally higher than that of unfrozen soils due to ice binding capacity with soil particles, and is strongly affected by a highly complex interaction between the solid soil skeleton and the pore matrix, composed of ice and unfrozen water. In this study, the direct shear test and unconfined compression test are carried out inside of a large-scaled freezing chamber, and the relationships between cohesion and unconfined compression strength under various freezing temperature conditions are discussed.

• Journal of the Korean Institute of Gas
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• v.7 no.4 s.21
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• pp.1-6
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• 2003

Freon gas has been replaced with LPG in the cosmetic industry because of its bad effects on environment. In this paper, skincare product with a cooling effect was developed using LPG as propellant. A cooling effect is obtained by the ice which is formed through spraying. Ice formation is affected by the composition of LPG and most of all, the high content of propane gas in the LPG results in the irregular surface of ice formed because of its high vapor pressure. Also the ratio of LPG to skincare solution affects the formation of ice.

• Journal of the Korean Geotechnical Society
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• v.32 no.12
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• pp.59-67
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• 2016

The strength of frozen soils is affected by size and shape of particles, and the amount of ice and unfrozen water. The objective of this study is to characterize the unfrozen water content and the unconfined compressive strength of the frozen soils according to the degree of saturations and silt fractions. The specimens are mixtures of sand, silt, and water. The silt fractions (SF), which are the ratio of the silt weight ($W_{silt}$) to the sand weight ($W_{sand}$), are 10% and 30%. In addition, the degrees of the saturation are 5%, 10%, 15%, and 20%. The specimens are frozen under the temperature of $-10^{\circ}C$ conditions. The uniaxial compression tests are conducted for 24 hours, 48 hours, and 72 hours after freezing to determine proper freezing time. The freezing time of 24 hours is chosen because the unconfined compressive strengths of specimens after 24 hours freezing times are similar to each other. Furthermore, the unfrozen water content is monitored during freezing using the TDR system. The unfrozen water content increases with the increase of the silt fraction and degree of saturation. The unconfined compressive strength of the frozen soils exponentially increases with increasing the degree of saturation. This study shows that the amount of ice has more influence on the strength of the frozen soils than the amount of unfrozen water.

• Food Science and Preservation
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• v.18 no.5
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• pp.811-816
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• 2011

Cryoextraction (a freeze concentration using an instrument) can increase the sugar concentration in grape juice by reducing its water content, similar to the natural freezing of grapes for natural ice wine. In this study, fermentation of freeze-concentrated Campbell Early grape (Vitis labruscana) juice to 36 $^{\circ}Bx$ was carried out using Saccharomyces cerevisiae strains D8 and S13 isolated from Korean grapes. During the fermentation, strains S13 and D8 showed rapid sugar reduction and alcohol production compared with S. cerevisiae Fermivin$^{(R)}$ used as a control. After nine-day fermentation, the residual sugar contents were lower in W13(9.77%) and D8 wine(9.07) than that in Fermivin$^{(R)}$ wine(14.0%). Total acid content was high in the D8>S13>Fermivin$^{(R)}$ wine, in that order. The acetaldehyde content was highest in the D8 wine and lowest in the Fermivin$^{(R)}$ wine, among the three. The methanol content was slightly higher in the S13 and D8 wines than in the Fermivin$^{(R)}$ wine. In the sensory evaluation, the S13 wine exhibited the highest score in flavor and taste among the three wines. Both the two S13 and D8 wines exhibited higher scores than Fermivin$^{(R)}$ wine in overall preference.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.3
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• pp.152-163
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• 2001

Based upon the sedimentological, geochemical and micropaleontological analyses of two sediment cores from the Antarctic Peninsula (AP), three distinct lithological units can be recognized: (1) ice-proximal an/or ice-distal diamictons in the lower part of the cores, accumulated just seaward of the grounding line of the ice shlef until 11,000 yrs BP; (2) diatomaceous mud between 6,000 and 2,500 yrs BP in the middle part, resulted from a large influx of organic materials by enhanced production of open marine condition; (3) diatomaceous sandy mud since 2,500 yrs BP, characterized by an increase in sand content and decrease in TOC and diatom abundance in the lower layers, which reflects the formation of more extensive and seasonally persistent sea ice. Based on the C-14 radiocarbon dating, the sub-ice shlef deposition of the diamicton on the AP western shelf completed around 11,000 yrs BP. Colder condition was reinstated between 12,800 and 11,600 BP with a dropin TOC content and diatom abundance, which is coincident with the Younger Dryas event in the North Atlanticregion. At this time, the ice shelf, that is now absent in the study area, appears to advance as evidenced by an abrupt increase in sea-ice taxa. A climatic optimum is recognized between 9,000 and 2,500 BP, coincide witha mid-Holocene climatic optimum 'Hypsithermal Warm Period' from the other Antarctic sites. During this time, diatomaceous mud accumulated by a large influx of organic materials by enhanced production occurred in openmarine condition. Around 2,500 BP, diatomaceous sandy mud reflects the formation of more extensive and seasonally persistent sea ice, coincident with the onset of the Neoglacial in the Antarctic. Our results provide evidence of climatic change from the Antarctic Peninsula`s western shelf that helps in determining the existence and timing of Holocene milennial-scale climatic events in the Southern Hemisphere.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.42 no.1
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• pp.95-103
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• 1997

This experiment was carried out to obtain the basic information necessary to establish suitable postharvest handling techniques and to keep high quality of the sweet(Danok 2), supersweet(Cooktail 86) and waxy(Chalok 1) corn which are mainly consumed as vegetable in Korea. Vegetable corns were cooled with ice fragments in the insulation box immediately after harvest and stored in low temperature warehouse at 0 to 2$^{\circ}C$. During the 15 days short-term storage, changes of chemical components were compared with those of uncooled corns. The losses of moisture in kernels were as high as 7.4 to 24.4％ in uncooled corns while those of ice cooled corns increased 0.4 to 0.5％ of their weight. The ratio of pericarp and alcohol insoluble solid(AIS) content increased as the storage days prolonged in all treatments but increasing rates were much higher in uncooled samples. On the other hand, the total sugar loss during storage was the least in supersweet corn when they were cooled with ice fragments in insulation box. After 5 days storage, the ice cooled samples showed the highest free amino acid contents compare to those of uncooled and stored at room temperature (25 to 3$0^{\circ}C$) or low temperature warehouse, and ${\gamma}$-aminobutylic acid (GABA) which was known as a fuctional amino acid was detected in all three kinds of vegetable corns.

• Food Science and Preservation
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• v.19 no.3
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• pp.413-419
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• 2012

Fermentation of ice apple wine from freeze-concentrated Fuji apple juice to 36 $^{\circ}Brix$ was carried out using Saccharomyces cerevisiae SS89, a sugar-tolerant wine yeast strain. The characteristics of the fermentation and the properties of ice apple wine were compared with those of S. cerevisiae W-3, an industrial wine yeast that was used as a control in this study. During the fermentation, the alcohol content increased more rapidly by S. cerevisiae SS89 together with the decrease of the soluble solid content, compared to S. cerevisiae W-3. It reached 12% (v/v) after 15 days of fermentation by S. cerevisiae SS89 (12.4%, v/v) and 21 days by S. cerevisiae W-3 (12.6%, v/v). The soluble solid contents of the SS89 and W-3 wines were 24.0 and 23.6 $^{\circ}Brix$, respectively. Lactic acid was detected at the highest level, followed by malic aid, among the organic acids in both wines. No big differences in the organic acid contents were observed based on the strains. In the SS89 wine, higher levels of methanol, propanol, butanol, and isoamyl alcohol were detected, together with a lower isobutanol content, compared with the W-3 wine. The SS89 wine showed higher level of intensity as well as higher Hunter's L and b color values compared to the W-3 wine. In the sensory evaluation, similar scores in color, flavor, taste, and overall preference were obtained in the two wines. Therefore, S. cerevisiae SS89 was thought to be useful for the rapid fermentation of ice apple wine.

• Microbiology and Biotechnology Letters
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• v.50 no.3
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• pp.361-374
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• 2022

For this study, we designed and produced mulberry low-fat ice cream supplemented with synbiotics (MLF-ISS). The sensory characteristics and physical, chemical, and microbiological qualities of MLF-ISS were then determined. Mulberry juice inoculated with or without probiotic (Lactobacillus plantarum TISTR 926 and Saccharomyces boulardii CNCM I-745) was also tested at 37℃ for 24 h to determine probiotic growth rate, pH, total anthocyanin content (TAC), total phenolic content (TPC), and antioxidant activity (AA). Only the TAC of mulberry juice inoculated with S. boulardii CNCM I-745 increased considerably (p < 0.05) among these parameters. MLF-ISS was produced with varied mulberry fruit concentrations (0, 10, 20, 30, or 40%) (w/w). The MLF-ISS prepared with 30% mulberry fruit (w/w) (30-MLF-ISS) had a higher score in appearance, color, and sweetness (p < 0.05) when sensory qualities were measured using the 9-point hedonic scale method. In the CIE lab system (L^*, a^*, b^*), the color values of 30-MLF-ISS were 27.80 ± 0.26, 12.99 ± 0.59, and 1.43 ± 0.05, respectively. The 30-MLF-ISS was also subjected to a proximate analysis. The melting rate of 30-MLF-ISS was 0.29 ± 0.03 g/min and the time it took for the first drop to fall was 37.00 ± 7.00 min. TAC, TPC, and AA of 30-MLF-ISS were observed to alter significantly (p < 0.05) during varied intervals of storage at - 18℃ (0, 30, and 60 days). The viability of probiotics in 30-MLF-ISS slightly decreased after storage at -18℃ for 8 weeks, but remained about 6 log CFU/g. During storage at -18℃ for 0 and 120 days, no pathogenic bacteria were detected in 30-MLF-ISS. These findings show that 30-MLF-ISS has nutritional and functional value, is free of foodborne pathogenic bacteria, is safe for consumers' health, and is suitable for application in the ice cream and related food industries.

• Geomechanics and Engineering
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• v.22 no.3
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• pp.245-254
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• 2020

The interaction between the frozen soil and building structures deteriorates with the increasing temperature. A nuclear magnetic resonance (NMR) stratification test was conducted with respect to the unfrozen water content on the interface and a shear test was conducted on the frozen soil-structure interface to explore the shear characteristics of the frozen soil-structure interface and its failure mechanism during the thawing process. The test results showed that the unfrozen water at the interface during the thawing process can be clearly distributed in three stages, i.e., freezing, phase transition, and thawing, and that the shear strength of the interface decreases as the unfrozen water content increases. The internal friction angle and cohesive force display a change law of "as one falls, the other rises," and the minimum internal friction angle and maximum cohesive force can be observed at -1℃. In addition, the change characteristics of the interface strength parameters during the freezing process were compared, and the differences between the interface shear characteristics and failure mechanisms during the frozen soil-structure interface freezing-thawing process were discussed. The shear strength parameters of the interface was subjected to different changes during the freezing-thawing process because of the different interaction mechanisms of the molecular structures of ice and water in case of the ice-water phase transition of the test sample during the freezing-thawing process.