• Journal of the Korea Institute of Building Construction
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• v.24 no.2
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• pp.193-202
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• 2024

This research delves into the evaluation of the suitability of ultrasonic pulse velocity as a diagnostic tool for early detection of frost damage in concrete. The investigation involves the measurement of compressive strength and ultrasonic pulse velocity concerning the depth of freezing for individual mortar specimens, followed by an analysis of their microstructure and their interrelation. The findings indicate a consistent decrease in both compressive strength and ultrasonic pulse velocity with increasing freezing depth. Furthermore, a correlation between compressive strength and ultrasonic pulse velocity concerning the depth of early frost damage is established. Consequently, the study asserts the potential of utilizing the ultrasonic pulse velocity method for early detection of frost damage in concrete, with prospects for quantifying the depth of damage through further research endeavors.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.1
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• pp.21-27
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• 1999

In this study, stress intensity factors KI, KII, KIII are existing at the same time to a hollow cylindrical bar of three dimension inclination crack. In order to investigate by experimentally the effect of the inclination angle $\psi$ of crack, artificial inclination cracks in the circumferential direction are put in the surface of a hollow cylindrical bar made by the epoxy-resin. Experimentally, stress analysis methods of stress intensity factors were proposed. But, suitable method are the caustic method and the photoelastic stress freezing method. The mixed mode of KI, and KII, were determined by the photoelastic method of the classical approach method and the FORTRAN language program of the used smallest square method.

• Clinical and Experimental Reproductive Medicine
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• v.31 no.1
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• pp.9-17
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• 2004

Objective: The aim of this study were to compare the effects of EG and PROH on cryopreservation of mouse and human embryos, and to find the optimal protocol for embryo freezing. Methods: Human embryos derived from fertilized eggs showing 3 pronuclei (PN) and mouse embryos were divided into two groups respectively: dehydrated with 1.5 M EG + 0.2 M sucrose or 1.5 M PROH + 0.2 M sucrose using the slow freezing method. Moreover mouse embryos were controlled the exposure time of cryoprotectant during dehydration or rehydration steps. Results: The survival rates of human embryos were 79.2% (84/106) in EG group and 77.9% (88/113) in PROH group. In mouse embryos, the survival and development rates up to blastocyst were 70.6% (245/347), 44.1% (123/279) in EG group and 62.1% (198/319), 45.1% (123/279) in PROH group, respectively. However, in EG group, partially damaged embryos after thawing were decreased compared to PROH group. In combination group, when the exposure time during dehydration and rehydration were reduced, the survival and embryonic developments were increased slightly, but not significant. Conclusion: Cryopreservation of mouse and human embryos at cleavage stage by using EG or PROH exhibited no statistical difference in the survival rate and/or developmental rate to blastocyst. However, the use of EG for cryopreservation of embryos might reduce the exposure time of the cryoprotectant because of a high permeation of EG and result in lessen its toxic effects.

• Journal of Dairy Science and Biotechnology
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• v.35 no.1
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• pp.39-45
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• 2017

The market for lactose-hydrolyzed milk is growing due to an increased awareness of lactose intolerance, and increased market interest for modified milk with health claims. The aim of this study was to compare the quality characteristics of 2% lactose-hydrolyzed milk with its lactose hydrolysis rate, with the goal of applying the method to dairy product monitoring in the future. We observed that the freezing point of milk significantly decreased with increasing lactose hydrolysis rate. A linear relationship was found between lactose concentration and freezing point, following the equation (y=-50.416x + 767.91). However, no significant changes were observed in other physicochemical properties of the milk (pH, titratable acidity, total solids and color) (p<0.05). In conclusion, we could predict the residual lactose content quickly and easily in 2% low fat milk by measuring its freezing point. This could represent an easy means for assessing the lactose hydrolysis rate of dairy products.

• Current Research on Agriculture and Life Sciences
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• v.6
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• pp.163-169
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• 1988

This study was conducted to predict the density changes according to concentration and temperature changes under freezing point. This information is needed for the design of freezing equipment and for the efficient utilization of refrigerating system. Orange juice, Apple juice, Grape juice and Sucrose solution were used for the measurement of density in this study at the temperature range from $-5^{\circ}C$ to $-40^{\circ}C$ and at the concentration range from 10 to 40%. The unfrozen water fraction of samples was determined by Heldman's method. The density values were determined by measuring the weight of a frozen solution at each temperature with a known volume. Solutions were placed in the thick-walled aluminum tubes. When the solution was frozen the excess ice was removed with a razor until the surface of the ice was flush with the top of the aluminum tube. The tube and ice were weighted immediately. Knowing the volume, tare weight, and final weight, the density could be determined. With this procedure, the data of density and unfrozen water fraction for fruit juices and sucrose solution were collected. The density prediction models of fruit juices and sucrose solution under freezing point were established by the optimization computer program with measured experimental data.

• Journal of Korean Society of Forest Science
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• v.103 no.4
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• pp.528-536
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• 2014

The aim of this study was to investigate the damage characteristics induced by winter freezing of evergreen broad-leaved trees distributed in urban area of warm temperate forest zone, which are gaining increased interest recently as climate change. The results of the study indicated that, as for 'stem injury', Camellia japonica Linne (59.6%) had the weakest damage, while Ternstroemia gymnanthera Sprague (83.3%) had the most severe damage. By the visual evaluation of freezing injury according to the characteristics of plantations environment, the observations of single planting (p<0.01) in planting method had weaker damage than those of group planting, the observations of under tree (p<0.001), plain (p<0.001), and organic matter plenty (p<0.05) in plantations characteristics had significant differences with relatively weaker damage than the observations of open space, slop, and scarcity, respectively. Tree height (-0.432) and crown width (-0.470) among growth factors were negatively correlated with the severity of damage, respectively. Therefore, the selection of tree species is vital for the successful creation of these urban forested area by making considerations of planting environment, and further research on evergreen broad-leaved trees is needed in this aspect.

• Clinical and Experimental Reproductive Medicine
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• v.25 no.1
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• pp.71-76
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• 1998

This study was carried out to examine whether the developmental capacity of bovine immature oocytes frozen ultra-rapidly using electron microscope (EM) grids and EFS30 can be obtained. As freezing solution, we used EFS30 which consisted of 30% ethylene glycol, 0.5 M sucrose, 18% ficoll and 10% FBS added in D-PBS. As criterior of oocyte viability, the rates of maturation, fertilization and embryonic development were determined. The results obtained in this experiment were summarized as follows: When ultra-rapidly frozen immature oocytes were thawed, 43.2% of them were survived. The rates of maturation (84.1%) and normal 2 pronuclei formation (57.5%) of frozen immature oocytes were not significantly different when compared to those of control (92.5, 65.0%). In addition, the rates of $\geq2$-cell (65.0%) and blastocyst formation (30.8%) of freezing group were not significantly different when compared to those of control (73.7, 35.7%). These results demonstrate that developmental capacity of frozen-thawed bovine immature oocytes can be successfully obtained when survived from the ultra-rapid freezing method using EM grid and EFS30.

• Korean Journal of Food Science and Technology
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• v.31 no.6
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• pp.1596-1603
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• 1999

Dongchimi (Korean-style fermented radish with juice) products were frozen to prevent further acidification and softening of texture by restraining microbial growth and enzyme activity during storage. Dongchimi juice and radish were separated prior to freezing process. Dongchimi radish was frozen at $-20^{\circ}C,\;-70^{\circ}C$ and immersed in liquid nitrogen and dongchimi juice was frozen at $-20^{\circ}C\;and\;-70^{\circ}C$. Frozen dongchimi samples were thawed with ambient temperatures of $4^{\circ}C\;and\;27^{\circ}C$ and with 915 MHz-microwave, respectively. Dongchimi radish immersed in liquid nitrogen and thawed with 915 MHz-microwave showed the highest pectinesterase activity and hardness, and the lowest polygalacturonase activity and color change, indicating that this quick freezing-quick thawing method can be used for the long-term storage of dongchimi products. Dongchimi juice frozen at $-70^{\circ}C$ and thawed with 915 MHz-microwave retained its pH and titrable acidity, and showed a largest reduction in total aerobic count and lactic acid bacteria.

• Transactions of the Korean Society of Mechanical Engineers
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• v.7 no.4
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• pp.434-440
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• 1983

For the determination of stress intensity factors, three methods have been used conventionally; the photoelastic method, the compliance method and the electrical resistance method. These methods, however, have common short coming upon experimental performance; the difficulty of cutting out sharp crack tips and arbitray crack forms similar to the practical one on the specimen. to eliminate this flaw, one of the author previously presented new methods, that is, for the determination of $K_{III}$ mode, the membrane analogy was applied and the slab analogy was used for the determination of $K_{I}$ and $K_{II}$ . The validity of this method was proved through the performance of a series of experiments of which theoretical solution are known.n.n.

• Culinary science and hospitality research
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• v.12 no.3 s.30
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• pp.108-118
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• 2006

This study is on different dry methods for Artemisia sp. which were not affected by the dry matter percent. Essential oil components such as 1,8-cineol and terpineol were highly affected by the dry method. 1,8-cineol and terpineol components were decreased by adaptation of the heated oven-drying method and the freeze-drying method. Borneol components were increased through shady sun-drying, sun-drying and freeze-drying. Heated oven drying method decreased the vitamin C content. Vitamin C content was decreased in oven-drying about 50% during this period, but only 10% decreased in the freezing dry method. Qualities were changed by different drying methods. Therefore, different dry methods of Artemisia sp. were applied to the flavorgen.