• Asian-Australasian Journal of Animal Sciences
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• v.15 no.11
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• pp.1553-1558
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• 2002

This study was carried out to obtain informations regarding the effect of N-acetyl-D-glucosamine in the LEY (lactoseegg yolk) diluent according to incubation time in 5 ml maxi-straw and the effects of freezing rate, thawing temperature and thawing time in the LEN (lactose-egg yolk and N-acetyl-D-glucosamine) diluent on acrosome morphology and motility of frozen-thawed boar sperm. The study showed that the LEN diluent was higher post-thaw NAR (normal apical ridge) acrosome than the LEY diluent for 0.5 h incubation at 37$^{\circ}C$. However, there were no differences between the LEN and LEY diluents on post-thaw sperm motility according to incubation time. The straws frozen from 5.0 cm (20$^{\circ}C$/min) to 17.0 cm (1$^{\circ}C$/min) above the liquid nitrogen surface did not show any significant differences on post-thaw sperm motility. However, the straws frozen above 5.0 cm from the liquid nitrogen surface were higher NAR acrosome than those frozen above 17.0 cm. The post-thaw percentages of motile sperm and NAR acrosome were significantly higher (p<0.05) for the maxi-straws submerged for 40 or 45 sec in a 52$^{\circ}C$ water bath than for 30, 35, 50 or 55 sec. The mean sample temperatures of maxi-straws after 40 or 45 sec submersion were 20.7 or 26.4$^{\circ}C$. In conclusion, the sample temperature of the thawed semen was very important for post-thaw sperm survival in the LEN diluent of 5 ml maxi-straw. When the temperature of the thawed semen was 20.7$^{\circ}C$, the percentages of motile sperm and NAR acrosome were highest.

• Proceedings of the Korea Concrete Institute Conference
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• 1996.04a
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• pp.123-128
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• 1996

Water in concrete has an effect on properties of concrete very much, such as shrinkage, creep, fire resistance, durability, freezing and thawing resistance. Therefore predicting the moisture distribution in concrete is very important. And since the diffusion process of water in concrete is strongly dependent on the temperature and pore humidity, the process is highly nonlinear phenomena. In this study, a finite element program which was capable of simulating the moisture distribution in concrete was developed, and differential drying shrinkage due to the water diffusion process was measured at the different positions of concrete. This F.E.M. program is shown that the analytical results of this study are in good agreement with experimental data. Shrinkage strain caused by moisture distribution was increased with the decrease of pore relative humidity.

• Solar Energy
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• v.18 no.4
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• pp.33-38
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• 1998

This paper reports the experimental results concerning the thermal performance of a freeze-protected direct solar water heating system. The direct system tested has been manufactured to prevent any breakage during harsh wintry conditions by specially designed riser and downcomer headers capable of relieving extra pressure due to freezing of water. The direct system tested has shown 10% improvement in its efficiency over that of a indirect type system using antifreeze as the heat transfer medium. It is felt that any direct system of its kind could galvanize the whole solar industry if further improvements are made to ensure its durability.

• Proceedings of the Korea Concrete Institute Conference
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• 1991.10a
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• pp.34-39
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• 1991

It is well-known that concretes under sea water environment show remarkably degrading phenomena physically by repeatable freeze-thawing action and chemically by penetration of soluted ions in sea water. In this study the influences of type of blending materials, their dosage and W/C ratio on freeze-thawing resistances of hardened cement concrete using foy ash, ground blast furnace slag, silica fume, EVA and SBR under sea-water environment were investigated.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.05
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• pp.447-450
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• 1997

A new technique for the preparation of porous vascular prostheses was investigated. Polyurethane solution (10 to 14wt%) was injected into a mold. After freezing at low temperature $(0^{\circ}C\sim-40^{\circ}C)$, solvent was dissolved out with water at $0^{\circ}C$ to form porous tubes. The average pore size $(<10{\mu}m)$and pore occupation (10% to 51%) were easily changed by changing polyurethane concentration, freezing temperature, and freezing methods. This technique can give a proper pore size $(30\sim60{\mu}m)$ for tissue ingrowth, and suitable compliances for matching with arteries and veins. This method might give a desired compliant graft for artificial implantation with the presently valid medical polymers.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.909-916
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• 2013

Concrete containing lightly burnt MgO has long term expansibility. It also could compensate for the thermal shrinkage of mass concrete, because the hydration of MgO proceeds at a slow pace to long-term age. Thus, lightly burnt MgO has been applied to the construction of mass concrete such as dams. Recently, the expansion characteristics of MgO concrete with fly ash that could be applied to mass concrete for the reduction of hydration heat have been studied and however, limited studies on its durability. This study investigates the long-term durability characteristics of fly ash concrete with lightly burnt MgO. The durability tests on carbonation, freezing-thawing, diffusion of chloride, and resistance to sulfate attack were carried out for MgO concrete with curing for 360 days in submerged condition with different temperature of 20 and $50^{\circ}C$. The results reveal that MgO concrete shows a greater resistance of carbonation, diffusion of chloride, and resistance to sulfate attack. On the other hand the resistance of freezing-thawing was little influenced by MgO powder.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.15 no.3
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• pp.199-206
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• 1982

Histological changes occurred by freezing storage and subsequent thawing, and changes of muscle fiber after heating and drying of the eel (Anguilla japonica) were observed under microscope . The results are as follows : (1) After one month of freezing storage the muscular tissue produced considerable number of extracellular and intracellular ice crystals. The sample stored at the temperature of $-40^{\circ}C$ produced ice crystals inside the muscle cells while sample stored at $-20^{\circ}C$, outside. (2) No changes were observed in the hypodermic fat after thawing regardless of storage temperature, while insufficient recovering of muscle cells were detected in the muscular tissue. Muscular tissues which have been stored $-20^{\circ}C$ showed severe change in shape due to dehydration. (3) Microscopic observation on muscle homogenate showed loss of transparency due to free-zing, disfiguration and contraction by drying and water seperation, and elasticity by heating.

• Solar Energy
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• v.20 no.3
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• pp.51-60
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• 2000

This paper deals with the design, construction and operation of a direct solar hot water heating system developed to harness the solar energy more effectively. The system introduced here uses a unique network of riser tubes and header pipes apart from the existing concept to exploit the physical properties of water which expands when it freezes. It also employs a special pressure relief mechanism for the header to prevent its breakage due to freezing. A number of tests are made to assure its functional reliability during frigid weather conditions and its superior performance over indirect systems.

• Journal of the East Asian Society of Dietary Life
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• v.20 no.6
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• pp.923-931
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• 2010

Effects of freezing period and chilling process after thawing on the physicochemical properties and palatability of hind shank meat from Korean native beef were investigated. There were no significant differences in the Hunter's color, volatile basic nitrogen (VBN) or collagen amount of hind shank meat upon freezing with vacuum packing at $-20^{\circ}C$ for 9 months. In addition, while pH, thiobarbituric acid (TBA) value, hardness, drip and boiling loss of hind shank meat increased and palatability decreased, there significant difference were observed only after 9 months. Softness, water holding capacity, L-glutamic acid, oleic acid, and polyunsaturated fatty acid contents increased upon chilling for 4 days after thawing, and there was a significant increase in palatability. The values of VBN and TBA increased markedly upon 6 days of chilling after thawing, and there was a significant decrease in palatability.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.409-414
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• 2002

This study is intended to develop the self water proof admixture for durability concrete by anti-corrosion inhibitor. Chloride induced corrosion of reinforcement is one of the main factor which cause the deterioration of concrete structure. When the substitute anti-corrosion agents for a part of self waterproofing agent, the corrosion-proof increases for the increased water proofing capacity. And proper self waterproofing agent by cement weight in concrete was generally positive effect to concrete compressive strength, slump, freezing and thawing resistance. Also, permeability and absorption show a straight decrease when self waterproofing agent is added.