• Food Science and Biotechnology
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• v.16 no.4
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• pp.590-593
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• 2007

The textural properties of doughs mixed with L-ascorbic acid (AA), trypsin hydrolyzed gluten peptide (THGP), and a mixture of AA-THGP were investigated using texture analyzer under the fermentation of the full formula and the freezing process. The full formula dough (FFD) required a shorter mixing time than the flour and water formula dough (FWD). The maximum resistance (Rmax) values of both the unfrozen and frozen doughs were lower for the FFD. The effects of AA and THGP additions were not significant (p<0.01) in FFD, however, they were significant in FWD. The freezing effect was significant (p<0.0001) for FFD, indicating that yeast fermented dough was much more sensitive to damage from freezing, which subsequently affected dough strength. Additions of AA (p=0.0026) and THGP (p=0.0097) had a significant effect on the extensibility (E-value) of unfrozen FWD, where THGP increased and AA decreased the E-value. However, freezing did not significantly effect the extensibilities of FWD (p=0.64) or FFD (p=0.21). The area of FFD was lower than the area of FWD for both the unfrozen and frozen doughs. However, the frozen dough mixed with THGP alone had the largest area overall. The addition of additives did not result in significantly different (p<0.01) areas under the curve, except in the frozen FFD. Freezing caused a statistically significant difference in the area of FWD (p=0.0045).

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.11a
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• pp.69-72
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• 2009

This research is focused on the applying of the foaming agent which can make the independent pore in the concrete structure in order to make a lightweight concrete structure. This lightweight foamed concrete can satisfy both the required strength and the mechanical properties as structural members. In addition, anti freezing-thawing properties also required. As a result of the unit volume-weight measurement, when the foaming agent mixed at 0.5% to 1%, the lightweight foamed concrete can be applied for the structural member. Also the density and compressive strength measurement results reveals that it will be suitable as structural member with 21MPa strength, when the density is betweenity8 to 1.9 and foaming agent quantities are 0.5% to 1%. Finally the result of freezing-thawing experiment, the effect freezing-thawing damage reduced according to adding foaming agent because those foaming agent make micro-pores in the structure which are not seen in the ordinary concrete structure.

• Smart Structures and Systems
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• v.17 no.1
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• pp.45-58
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• 2016

Freezing and thawing cycles induce deterioration and strength degradation of concrete structures. This study presumes that a large quantity of contact-type defects develop due to the freezing and thawing cycles of concrete and evaluates the degree of defects based on a nonlinearity parameter. The nonlinearity parameter was obtained by an impact-modulation technique, one of the nonlinear ultrasonic methods. It is then used as an indicator of the degree of contact-type defects. Five types of damaged samples were fabricated according to different freezing and thawing cycles, and the occurrence of opening or cracks on a micro-scale was visually verified via scanning electron microscopy. Dynamic modulus and wave velocity were also measured for a sensitivity comparison with the obtained nonlinearity parameter. The possibility of evaluating strength degradation was also investigated based on a simple correlation of the experimental results.

• Integrative Medicine Research
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• v.6 no.1
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• pp.12-18
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• 2017

Cryopreservation is a process that preserves organelles, cells, tissues, or any other biological constructs by cooling the samples to very low temperatures. The responses of living cells to ice formation are of theoretical interest and practical relevance. Stem cells and other viable tissues, which have great potential for use in basic research as well as for many medical applications, cannot be stored with simple cooling or freezing for a long time because ice crystal formation, osmotic shock, and membrane damage during freezing and thawing will cause cell death. The successful cryopreservation of cells and tissues has been gradually increasing in recent years, with the use of cryoprotective agents and temperature control equipment. Continuous understanding of the physical and chemical properties that occur in the freezing and thawing cycle will be necessary for the successful cryopreservation of cells or tissues and their clinical applications. In this review, we briefly address representative cryopreservation processes, such as slow freezing and vitrification, and the available cryoprotective agents. In addition, some adverse effects of cryopreservation are mentioned.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.9
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• pp.1291-1295
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• 2004

Histology and transmission electron microscopy studies were carried out on buffalo muscles that were subjected to repeated freeze-thaw cycles at -10 and $-18^{\circ}C$. In the first freeze thaw cycle ($-10^{\circ}C$) structures of muscle showed slight change and closely resembled to those of normal muscle. There were frequent gaps in the half way across the fibres and some cracks in individual fibre were also noticed in second freeze thaw cycle. In the muscle frozen at $-18^{\circ}C$, more pronounced shrinkage with extensive damage of fibres with tearing was observed. The interfibrillar gaps were wider, shrinkage and tearing of the fibres were more distinct after second freeze-thaw cycle. After the second cycle, the interior portion showed large scale degradation of the ultrastructure. Our studies of buffalo muscle showed that under the proper condition, little structural damage takes place in the meat histology and ultrastructure under repeated freeze-thaw conditions. This study adds continued weight to the evidence that limited freeze-thaw cycles will not deteriorate the quality of meat.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.807-812
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• 2001

This study is peformed for checking the limitation and application of each curing/heating methods on cold-weathering mat foundation construction, considering temperature control, early strength security and temperature declination range limit, by means of concrete material properties and thermal analysis technique that were published previously. In the result of this analysis, we checked the open air temperature and mat depth that are possible to apply each curing/heating methods on cold-weathering construction and found curing/heating time of each methods that is able to prevent early aged freezing damage and thermal crack

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.184-187
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• 2004

There are many factors that generate the early deterioration of the concrete structure. As the one of the representative factors, we can think an invasion of the water, air and so on. The water and air invade in inside void along the capillarity and they become the cause that the durability like corrosion of layer department due to freezing and thawing, inside steel frame corrosion, and so on blacks. Therefore with covering permeability covering waterproofing material of fluid condition in outer wall, intercepting the deterioration factor due to the infiltration of water from outside and for salt damage of concrete layer department, freezing damage and neutralization, it needs to improve durability of structure. This study separately examined physical and chemical specific of quality liguid siliceous of waterproofing material. Therefore as this applys the construction site, it improves the durability of concrete structure. Further this presents the application plan from the construction market against the new material.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.05a
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• pp.13.2-17
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• 2003

When fresh concrete is exposed to low temperature, the concrete may suffer frost damage due to freezing at early ages and strength development may be delayed. One of the solution methods to resolve these problems is to lower freezing temperature of concrete by the use of chemical admixture called Accelerators for Freeze Protection. In this study, it was the results of appling cold weather concrete using Accelerator for Freeze Protection in the Daewoo Trump world field. Before the application of the cold weather concrete using accelerator for freeze protection, we executed the some test in the laboratory and mock-up test in the field. We examined the manifestation of compressive strength complying with the amount of Accelerators for Freeze Protection and curing conditions, and then made a selection of most suitable amount of Accelerators for Freeze Protection.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.10a
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• pp.313-318
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• 1998

Generally, the concrete constructed during cold weather has the frozen damage which cause the fatal damage so that heat curing and sheet curing was performed to prevent the early freezing of concrete. However, partial refrigeration caused by thermal gradient has many troubles so that the construction hasn`t been done as possible. This paper presents the development of strenth properties and optimal mix design against frozen damage under the cold weather, 1$0^{\circ}C$ below the zero.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.1
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• pp.19-28
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• 2017

In this paper, detailed safety inspection reports on the 915 expressway bridges which had been published from 1996 to 2010 are collected and condition of these bridges are analyzed. Damages are categorized into 'damage by defect', 'damage by physical force', and 'damage by deterioration' and the concept of damage possession rate is introduced to investigate the occurrence time and the characteristics of damages. Based on the top 10 damage patterns of expressway bridges and the deterioration characteristics of heavy snow and freezing cold area, reasonable improvement direction of inspection activity is suggested. From this study, it is known that improvement of inspection regularization during construction or at completion stage of bridges is needed. Since the deterioration progress of the heavy snow and freezing cold area is faster than that of general area, environmental characteristics should be considered in inspection activity. The results of present study can be widely used for improvement of inspection activity of expressway bridges.