• Journal of Korea Soil Environment Society
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• v.1 no.1
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• pp.103-109
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• 1996

The cover liners at municipal and hazardous waste landfill is not emphasized as much as the bottom liners. However, one of the most effective reason of landfill destroy is the cover liner failure. The cover system at municipal and hazardous waste landfill, 1 perform the following functions, at minimum: promote surface runoff, impede infiltration, protect settlement in the landfill, and provide a buffer from surface exposure of the waste. This research was to expand the existing knowledge base of landfill cover liner behavior during period of freeze/thaw Also, the great Lysimeter was built in the laboratory to provide as much as same condition with the field and three designs were simulated by actual cover materials. The result of simulation indicated the clay was effected by freezing/thawing. The degradation of cover liners in the frost penetration affects the physical, engineering properties of clay. these factors may consider to design and construct of the landfill. This paper provides the description of testing cover liners, experimental results and a discussion of the results of the simulation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.4
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• pp.353-358
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• 1985

Three kinds of aqueous solution of tobacco extracts are used as a new experimental material. It is measured how the operating condition, freezing point, viscosity as fundamental properties have the relation to concentration and temperature of the solution. The results of this study are obtained as follows. 1) The freezing point of the solution $(t_m)$ is presented; $t_m=-{\frac{18.6X}{170-{\frac{X}{100}}(170+18)}}$ 2) The correlation of the viscosity, the temperature and the concentration of the solution is followed; $log_{10{\mu}}={\frac{1585}{T}}+2.11{\frac{X}{100-X}}-5.50$ 3) The ice crystals whose circumference is a toothed wheel are made from high concentrated solution, and the thick plate shaped ones are done from the low concentrated solution.

• Journal of Embryo Transfer
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• v.27 no.1
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• pp.45-50
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• 2012

The objective of this study is to estimate the effect of adding TES to LEY and FGE freezing extender for the sperm viability, acrosomal morphology and DNA fragmentation from miniature pig sperm, we evaluated sperm characteristics in TFGE, TLE and LEY with various thawing condition ($37^{\circ}C$ for 20 sec, 45 sec and $75^{\circ}C$ for 5 sec, respectively), and in different concentration of glycerol at 1%, 1.5%, 3%. The sperm viability and normal acrosome intact(NAI) in TFGE (Viability : $60.3{\pm}2.4$, NAI : $58.6{\pm}2.2%$), TLE ($61.3{\pm}2.4$, $62.2{\pm}2.2%$) extender significantly(p<0.05) increased than that in LEY ($50.2{\pm}2.4$, $54.5{\pm}2.2%$) extender thawed at $75^{\circ}C$ for 5 sec. According to the results from glycerol concentration, the viability and NAI of miniature pig sperm in 1.5% glycerol TLE ($66.1{\pm}3.2$, $66.2{\pm}1.0%$) was highest among the experimental groups. In accordance with this, DNA fragmentation rates was the lowest in TLE ($43.3{\pm}0.5%$) while that in LEY ($63.5{\pm}2.3%$) is the highest. Therefore, these results suggest that TLE extender method for freezing- thawing of miniature pig sperm increased the viability after thawing.

• Journal of the Korean Geosynthetics Society
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• v.9 no.3
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• pp.39-45
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• 2010

When the ground temperature drops below $0^{\circ}C$, wet soils expand due to the ice formation in their porous space. This results in frost heave which causes structural stability problems. Frost heave is attributed by several factors such as physical soil properties and heat transfer including pore water phase change. Due to the complex physical phenomena, reliable and verified multi-dimensional numerical models for frost heave problems are still in a research stage. This study presents an efficient and simple method of overcoming numerical problems associated with sudden jump of heat capacity due to the phase change from water to ice in the pore space. This paper proposes heat transfer equation and finite element method when the saturated soils or porous rocks are subjected to freezing. Numerical analyses using the proposed method agree well with the known closed form solution and the laboratory test results.

• Journal of Veterinary Clinics
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• v.17 no.2
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• pp.431-437
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• 2000

Evaluation of viability and capacitation of canine sperm is of great importance to deter- mine good condition for freezing canine semen and consequently to improve conception rate by arti-ficial insemination. Semen were collected from nine male dots which had been proved to be fertile in the post and the semen were treaded for freezing procedure. Semen were thawed at 37$^{\circ}C$ for 30 seconds. In this study, hypoosmotic swelling(HOS) test and chlortetracycline(CTC) test were per- formed to evaluate post-thaw viability and capacitated status of sperm, respectively. In HOS test far canine sperm, the highest percentage of curled sperm was shown at 60 mOsm. In HOS test for canine semen, there were considerably significant correlation between HOS values and sperm motil- ity(r=0.9064, p<0.01) and converse correlation between HOS values and sperm abnormality(r=- 0.6905, p<0.05). The sperm viability and HOS-values for chilled extended semen were significantly decreased from 0 to 72 hours during storage at 5$^{\circ}C$ (p<0.05). Of the media added to canine semen after thawing, the most capacitated sperm were shown in CCM(p<0.01), and then This Fructose Cit- rate(TFC) medium with calcium from 3 hours after incubation with media. It was concluded that HOS test is of great value to determine the viability and motility of canine sperm, whereas CTC test is usable to determine the capacitated status. Consequently, both tests were thought to be useful as the additional tests to standard semen analysis.

• Clinical and Experimental Reproductive Medicine
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• v.26 no.2
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• pp.251-256
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• 1999

The present study was conducted to evaluate whether vitrification could be used for ovarian tissue preservation. The important issue here is that the vitrification is very simple, easy, and economical compared to the conventional cryopreserving method that using automatic freezing instrument. Human ovarian cortical tissues were cryopreserved by vitrification with 5.5 M ethylene glycol and 1.0 M sucrose as cryoprotectant. Three points of temperature ($4^{\circ}C$, room temperature, and $37^{\circ}C$) and two points of duration (5 or 10 minutes) for cryoprotectant treatment were examined to determine the best condition for vitrification of the human ovarian cortical tissues. After thawing, viability of the isolated primordial follicles was examined by dye-exclusion method. Histological appearance of tissues before and after the cryopreservation was evaluated. There was no toxic effect of the 5.5 M ethylene glycol on the primordial follicles. However, when the tissues were treated with cryoprotectant at $37^{\circ}C$ for 10 minutes and exposed to liquid nitrogen, it seems likely that there is certain deleterious effects on the viability of the primordial follicles. The highest viability of the primordial follicles was obtained with the treatment of cryoprotectant at room temperature for 10 minutes. Follicles and oocytes survived after freezing and thawing had the similar normal shapes as was seen in the specimens before cryopreservation. It would be useful to apply vitrification in establishing ovarian tissue banking for clinical purposes.

• Food Science and Preservation
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• v.14 no.5
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• pp.462-468
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• 2007

In this study, the quality effect of soaking in alum water, soaking in electrolyzed oxidizing water, and freezing during storage, on peeled chestnuts, were analyzed. When soaked in 0.1% (w/v) alum water, peeled chestnuts showed good characteristics in terms of weight loss, decomposition, and color preservation. However, texture and taste qualities rapidly decreased with increases in storage time. When soaked in twice their own weight of electrolyzed oxidizing water(pH 2.61, ORP 1,142 mV) for 10 min, the samples were preserved in an optimally edible condition. When frozen at $-10^{\circ}C$ for 5 min, the samples were suitable for use as material for processed chestnut produce, as was also the case when pretreatment with electrolyzed oxidizing water was employed.

• Tunnel and Underground Space
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• v.15 no.3 s.56
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• pp.169-176
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• 2005

The decreasing pattern of underground temperature measured at 'Gonjiam cold storage cavern' during 7 years which was the first commercial scale underground food storage cavern in Korea was analyzed. The variation of energy consumption was discussed by comparing the consumed energy at the initial operation stage with that at later stage, when the temperature distribution reached a stabilized condition. The point to be considered at the design stage was also discussed by comparing the required refrigerator capacity at the initial operation stage with that at later stage. The extra energy to freeze the groundwater contained in pore space was discussed by analyzing the changing pattern of the rock temperature. The variation of measured rock temperature was compared with the estimated temperature using a numerical code, FLAC. The accuracy of the numerical estimation was discussed by comparing the heat flux measured by the operation time of the refrigerator with that estimated numerically.

• Progress in Superconductivity and Cryogenics
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• v.24 no.3
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• pp.62-67
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• 2022

Liquid hydrogen (LH₂) has a higher density than gaseous hydrogen, so it has high transport efficiency and can be stored at relatively low pressure. In order to use efficient bulk hydrogen in the industry, research for the LH₂ supply system is needed. In the high-pressure hydrogen station based on LH₂ currently being developed in Korea, a heat exchanger is used to heat up supercritical hydrogen at 700 bar and 60 K, which is pressurized by a cryogenic high-pressure pump, to gas hydrogen at 700 bar and 300 K. Accordingly, the heat exchanger used in the hydrogen station should consider the design of high-pressure tubes, miniaturization, and freezing prevention. A helical heat exchanger generates secondary flow due to the curvature characteristics of a curved tube and can be miniaturized compared to a straight one on the same heat transfer length. This paper evaluates the heat transfer performance through parametric study on the distance between coils, guide effect, and anti-icing design of helical heat exchanger. The helical heat exchanger has better heat transfer performance than the straight tube exchanger due to the influence of the secondary flow. When the distance between the coils is uniform, the heat transfer is enhanced. The guide between coils increases the heat transfer performance by increasing the heat transfer length of the shell side fluid. The freezing is observed around the inlet of distribution tube wall, and to solve this problem, an anti-icing structure and a modified operating condition are suggested.

• Computers and Concrete
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• v.30 no.6
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• pp.421-432
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• 2022

Recently, the interminable ozone depletion and the global warming concerns has led to construction industries to seek for construction materials which are eco-friendly. Regarding this, Geopolymer Concrete (GPC) is getting great interest from researchers and scientists, since it can operate by-product waste to replace cement which can lead to the reduction of greenhouse gas emission through its production. Also, compared to ordinary concrete, geopolymer concrete belongs improved mechanical and durability properties. In spite of its positive properties, the practical use of geopolymer concrete is currently limited. This is primarily owing to the scarce structural, design and application knowledge. This study investigates the Mechanical and Durability of Geopolymer Concrete Containing Fibers and Recycled Aggregate. Mixtures of elastoplastic fiber reinforced geopolymer concrete with partial replacement of recycled coarse aggregate in different proportions of 10, 20, 30, and 40% with natural aggregate were fabricated. On the other hand, geopolymer concrete of 100% natural aggregate was prepared as a control specimen. To consider both strength and durability properties and to evaluate the combined effect of recycled coarse aggregate and elastoplastic fiber, an elastoplastic fiber with the ratio of 0.4% and 0.8% were incorporated. The highest compressive strength achieved was 35 MPa when the incorporation of recycled aggregates was 10% with the inclusion of 0.4% elastoplastic fiber. From the result, it was noticed that incorporation of 10% recycled aggregate with 0.8% of the elastoplastic fiber is the perfect combination that can give a GPC having enhanced tensile strength. When specimens exposed to freezing-thawing condition, the physical appearance, compressive strength, weight loss, and ultrasonic pulse velocity of the samples was investigated. In general, all specimens tested performed resistance to freezing thawing. the obtained results indicated that combination of recycled aggregate and elastoplastic fiber up to some extent could be achieved a geopolymer concrete that can replace conventional concrete.