• Journal of Advanced Marine Engineering and Technology
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• v.41 no.3
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• pp.176-181
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• 2017

This study attempted to examine a method of anti-freezing on a plate-type heat exchanger in a low-temperature environment. Freezing condition was observed after ultrasonic waves were generated. Data were recorded to determine the optimal conditions for freezing. Ethylene glycol, which is commonly used in antifreeze formulations, was used as the brine, and the temperature was varied between -8 and $-16^{\circ}C$. The water for freezing provided by the thickness of 1-3 mm. In addition, experiments were conducted by adjusting the output to identify the changes that occurred due to the incidence of ultrasonic energy. The results of the anti-freezing effect were brine temperature, freezing thickness, and frequency band of ultrasonic waves.

• Journal of Embryo Transfer
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• v.13 no.1
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• pp.1-9
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• 1998

In order to improve the cryopreservation by vitrification or slow freezing of nuclear transplant rabbit embryos, the effects of factors affecting embryo cryopreservation such as cryoprotectants, equilibration, cooling rate and post-thaw dilution on post-thaw survial and development were determined using intact embryos of morular stage. And the post-thaw development of nuclear transplanted embryos cryopreserved under the optimal conditions examined was compared between vitrification and slow freezing. The cryoprotectant solution used was ethyleneglycol-ficoll-sucrose (EFS) or ethyleneglycol-poly-vinylpyrrolidone-galactose- I (EPG- I ) for vitrification, and EPG- II for slow freezing. To examine the viability of frozen-thawed embryos, the nuclear transplanted embryos were co-cultured in TCM-199 plus 10% FBS with bovine oviduct epithelial cells(BOEC) for 24 hrs and the intact morulae were co-cultured with BOEC for 5 days and 3 days to hatching blastocyst stage in 39 ˚C 5% $CO_2$ incubator. The results obtained were as follows: Following vitrification with EFS, the post-thaw development of rabbit morulae to hatching blastocyst was significantly(P<0.05) higher in compacted stage(82.4%) than in early morular stage(60.0%). The post-thaw development of compacted morulae to hatching blastocyst was similarly high in vitrification with EFS(82.4%), EPG- I (85.0%) and in slow freezing with EPG- II (83.3%). Following vitrification with EPG- I, the post-thaw development of intact rabbit morulae to hatching blastocyst was similar as 78.0% and 85.0% in 1-step and 2-step post-thaw dilution, respectively. The post-thaw development of nuclear transplanted rabbit embryos of compacted morulae stage to hatching blastocyst was similarly 43.6% and 40.0% in vitrification with EPG- Iand slow freezing with EPG- II, respectively. These results indicated that the rabbit nuclear transplant and intact embryos of morulae stage could be well cryopreserved with either vitrification or slow freezing procedure.

• Magazine of the Korean Society of Agricultural Engineers
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• v.33 no.2
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• pp.112-119
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• 1991

Some experiments were carried out to investigate the effects of freezing and thawing on the strength and strain characteristics of alluvial silty clay under the different temperatures, loading and moisture conditions. The results were as follows; 1. The soil used was proved to be consisted of silty clay with honey-combed structure, and showed higher dilatancy, frost activity and lower stability in natural state. 2. Soil treated with freezing and thawing cycles showed lower compressive strength compared with the non treated, The strength decreased with incement of freezing and thawing cycles. It's shapes of stress-strain curves were flat and did not formulate a peak while the peak strength of higher moisture content soil decreased with the increment of moisture content. It's decrement ratio was most distinctly shown at the first one cycle of freezing and thawing. 3. The cohesion decreased due to freezing and thawing cycles but internal frcition angle was not changed. 4. The liquid limit decreased with increment of freezing and thawing cycles, and became almost constant after three cycles of freezing and thawing. 5. The strength under simple loading at failure mode was appeared to be higher compared with the cyclic loading after freezing and thawing but initial moisture content effect was not observed. 6. Ice lense was not observed within 50% of ice content ratio but observed over 100%. The higher the ice content ratio, the higher the peak strength. As a matter of fact, it seems that an optimum ice content ratio exists for plastic mode and the least compressive strength.

• International Journal of Highway Engineering
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• v.12 no.3
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• pp.71-77
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• 2010

Anti-freezing layer does not used in case of non frost heaving in subgrade soils. In this case, the modulus of subgrade soils were varied with freezing and thaw cycles under non frost heaving. That effect should be properly considered in pavement design. Impact resonance test that is nondestructive testing method was used for continuously determining the modulus of subgrade soils during freezing and thaw cycle. The modulus of subgrade soils was identical with freezing and thaw cycles under closed freezing and thaw system which is no water supplement into specimen during testing. There was also no difference in the modulus of subgrade soil between before and after freezing-thaw cycles for all specimens with different water content and density. That is thaw-weakening of subgrade soils do not occur under closed freezing and thaw system. The moduli at freezing conditions are varied with water content and density, but it can be ignored in practical design sense.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.2
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• pp.230-238
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• 2016

This study examined the effects of freezing and thawing conditions on quality of Hanwoo bottom round. The beef samples were frozen by air blast freezing at $-20^{\circ}C$ or ethanol immersion freezing at $-70^{\circ}C$ and then stored at $-20^{\circ}C$ for 10 days. After 10 days of storage, the frozen samples were thawed with air blast thawing at $4^{\circ}C$ or water immersion thawing at $4^{\circ}C$ and subjected to subsequent analyses of drip loss, water holding capacity, thiobarbituric acid reactive substance (TBARS), volatile basic nitrogen (VBN), total aerobic bacteria, and microstructure. Drip loss significantly increased in samples treated with air blast freezing compared to ethanol immersion freezing, whereas freezing and thawing processes had no significant impact on water holding capacity of the samples. Thawing conditions had a much stronger influence on the TBARS and VBN of the samples than freezing conditions. There was no significant difference in the population of total aerobic bacteria among the four samples subjected to one freeze-thaw cycle. In addition, to analyze the effects of freeze-thaw cycle on the quality of beef, three freeze-thaw cycles were performed during storage. Multiple freeze-thaw cycles increased drip loss, TBARS, and VBN and decreased water holding capacity, accelerating microstructural damage. These data indicate that Hanwoo bottom round can be rapidly frozen and thawed by using ethanol immersion freezing and water immersion thawing methods with minimal impact on meat quality.

• Korean Journal of Animal Reproduction
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• v.16 no.3
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• pp.217-224
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• 1992

These studies were carried out ot investigate on the transferred embryo development following ultrarapid frozen for 8-cell and morula of in vitro fertilization mouse embryos. The post-thaw embryo survival was evaluated and compared by cell stage of embryos and by equilibration time before ultrarapid freezing. The results obatined were summerized as follows: 1. The effects of equilibration time of 3 vs. 6 minutes before ultrarapid freezing and after thawing on the morphological survival and the viability of 8-cell and morulas embryos were not significant. 2. When the ultrarapid frozen-thawed 32 eight-cell and 33 morula embryos, and 30 fresh blastocysts were transferred to pseudopregnant recipient mice, the number of normal offsprings produced were 9(28.1%), 14(42.4%) and 18(60.0%), respectively. From the above resutls, it was concluded that the optimal conditions of pH osmolality of the media for mouse IVF and embryo culture, and the period of sperm preincubation might be 7.1, 310 mOsm and 120 min., respectively,a nd somewhat high conception rate might be resulted from transfer of frozen embryos of morula stage and fresh embryos of blastocyst stage.

• Food Science and Preservation
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• v.22 no.1
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• pp.44-50
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• 2015

This study was performed to optimize the preparation of frozen lotus roots. Prior to freezing, an optimal blanching condition at $100^{\circ}C$ for 5 min was established, based on the microbial growth, texture, total phenolic content (TPC), and sensory evaluation results. The blanched samples were then frozen under various freezing conditions ($-20^{\circ}C$ in a freezer for 2 hr, $-70^{\circ}C$ in a gas nitrogen convection chamber for 7 min, and $-196^{\circ}C$ in liquid nitrogen for 20 sec), and their qualities after thawing were determined. The scanning electron microscopic analysis indicated that the microstructure of the sample frozen at $-70^{\circ}C$ was similar to that of the control sample, compared with the other freezing conditions (-20 and $-196^{\circ}C$). The antioxidant activities of the frozen samples decreased compared to those of the control, but there was no significant (p<0.05) difference among the treatments. In terms of TPC, the samples frozen at -70 and $-196^{\circ}C$ had significantly (p<0.05) higher values than the sample frozen at $-20^{\circ}C$. In addition, the drip loss of the sample frozen at $-20^{\circ}C$ was higher than those of the other frozen samples. These results suggest that freezing at $-70^{\circ}C$ in a gas nitrogen convection chamber can be an optimal freezing method of producing high-quality frozen lotus roots.

• Journal of the Korean GEO-environmental Society
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• v.17 no.5
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• pp.37-46
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• 2016

In order to determine the variability of environmental characteristics of lightweight air-foamed soil using marine clay according to freezing-thawing and soaking conditions, unconfined compressive strength of the lightweight air-foamed soil samples made by changing the amount of cement under curing conditions of outdoor low temperature, underground or indoor wetting were observed. Compressive strength was not increased under freezing-thawing (temperature range of $-9.1^{\circ}C{\sim}17.2^{\circ}C$) regardless of the amount of cement but the more cement using, it was increased rapidly by underground curing conditions within 30 cm beneath ground level. Therefore, it is necessary to install insulation layer cutting off exterior cold air after construction of lightweight air-foamed soil in condition of freezing-thawing. Bulk density was increased too small under the long-time soaking condition, it tended to decrease rapidly when samples were dried up and had below 6% of water contents. But variability of compressive strength and bulk density was very small for preventing drying and keeping its wet state. The lightweight air-foamed soil that installed beneath ground water level or covered by soil can be evaluated as a long-term reliable construction material.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.43 no.3
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• pp.172-178
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• 1998

Freezing-resistant plants can survive subzero temperatures by withstanding extracellular ice formation. During cold acclimation, their leaves accumulate antifreeze proteins (AFPs) that are secreted into the apoplast and have the ability to modify the normal growth of ice crystals. Three barley, two wheat and two rye cultivars were grown under two different temperature regimes (20/16$^{\circ}C$ and 5/2$^{\circ}C$, day/night). Apoplastic proteins from winter cereals were separated by SDS-PAGE and detected with antisera to AFPs from winter rye. Apoplastic proteins accumulated to much higher levels in cold-acclimated (CA) leaves compared with nonacclimated (NA) ones in winter cereals. After cold acclimation, the protein concentration of apoplastic extracts increased significantly from 0.088 $mgmL^{-1}$ to 0.448 $mgmL^{-1}$, with about 5-fold increment. Also, the apoplastic protein content per gram leaf fresh weight in CA leaves ranged from 31 $\mu\textrm{g}$ $(gFW)^{-1}$ to 120 $\mu\textrm{g}$ $(gFW)^{-1}$ with an averaged value of 77 $\mu\textrm{g}$ $(gFW)^{-1}$, and coefficients of variation of 54.9%. The CA leaves in Musketeer (a Canadian winter rye cultivar) showed the greatest AFPs and antifreeze activity followed by 'Geurumil' (a Korean winter wheat cultivar), and 'Dongbori l' (Korean facultative barley cultivar). The proteins secreted into the wheat leaf apoplast at CA condition were more numerous than those observed in winter rye, where two $\beta$-1,3-glucanase-like proteins (GLPs), two chitinase-like proteins (CLPs) and two thaumatin-like proteins (TLPs) accumulated during cold acclimation. The proteins in barley leaf apoplast at CA conditions were a little different from those in wheat leaves. The AFPs were various among and within species. More freezing-resistant cultivars had more clear and numerous bands than less freezing-resistant ones. The high determination coefficient ($R^2$ =91 %) between freezing resistance and AFPs per gram leaf fresh weight indicated that the amount of AFPs was highly related to freezing resistance in winter cereal crops.

• International Journal of Highway Engineering
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• v.18 no.2
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• pp.83-90
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• 2016

PURPOSES : Nowadays, cavity phenomena occur increasingly in pavement layers of downtown areas. This leads to an increment in the number of potholes, sinkholes, and other failure on the road. A loss of earth and sand from the pavement plays a key role in the occurrence of cavities, and, hence, a structural-performance evaluation of the pavement is essential. METHODS: The structural performance was evaluated via finite-element analysis using KPRP and KICTPAVE. KPRP was developed in order to formulate a Korean pavement design guide, which is based on a mechanical-empirical pavement design guide (M-EPDG). RESULTS: Installation of the anti-freezing layer yielded a fatigue crack, permanent deformation, and international roughness index (IRI) of 13%, 0.7 cm, and 3.0 m/km, respectively, as determined from the performance analysis conducted via KPRP. These values satisfy the design standards (fatigue crack: 20%, permanent deformation: 1.3 cm, IRI: 3.5 m/km). The results of FEM, using KICTPAVE, are shown in Figures 8~12 and Tables 3~5. CONCLUSIONS: The results of the performance analysis (conducted via KPRP) satisfy the design standards, even if the thickness of the anti-freezing layer is not considered. The corresponding values (i.e., 13%, 0.7 cm, and 3.0 m/km) are obtained for all conditions under which this layer is applied. Furthermore, the stress and strain on the interlayer between the sub-grade and the anti-freezing layer decrease gradually with increasing thickness of the anti-freezing layer. In contrast, the strain on the interlayer between the sub-base and the anti-freezing layer increases gradually with this increase in thickness.