• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.625-630
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• 2002

The availability of natural aggregates has decreased in recent years due to depleting reserves. From the viewpoint of energy and resources saving, it may be advantageous to use the waste concrete as construction aggregates. The purpose of this study is to analyze petrographic and chemical properties of recycled aggregate, and to investigate the resistance of concrete to rapid freezing and thawing by using replacement ratios (0, 10, 20, 30, 40, 50, 60, 70, 100% ) of recycled aggregate.

• Proceedings of the Korea Concrete Institute Conference
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• 1997.10a
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• pp.456-461
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• 1997

The purpose of this experimental study are to produce a durable concrete and to investigate the various factors that can deteriorate the concrete when freezing and thawing activity. Among the various factors that can influence the frost resistance of concrete, this study examined mainly the relationship of the frost resistance with the water-cement ratio, admixture and admixture replacement ratio and propose the available water-cement ratio, admixture and admixture replacement ratio.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2003.05a
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• pp.113-114
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• 2003

굴은 세계적으로 100∼120종이 알려져 있으나, 우리나라에서는 주로 남해안의 청정해역에서 생산되며 산업적으로 가장 중요한 양식 굴은 참굴 (Crassostrea gigas)이다. 굴은 10∼3월에는 주로 생굴로 식용하고 있고, 4∼6월까지는 통조림과 IQF 등의 가공원료로 이용하고 있다. 우리나라의 굴 생산량은 매년 20 여만 M/T내외로서, 이중처리동결품 (IQF 18,000 M/T 내외, 통조림 5,000 M/T, 건굴 400 M/T, 그리고 굴젓갈등의 염신품으로 300M/T정도, 즉 생산량의 약13%만이 가공품 원료로 이용되고 있을 뿐 생산량의 대부분이 생굴로 소비되고 있는 실정이다. (중략)

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 1999.10c
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• pp.625-631
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• 1999

In this study, a series of test was conducted to show the characteristics of freezing -thawing process on soilcrete using the soft clay in a redevelopment paddy area, was treated with cement and several additives such as Beestar, CaSO4 , MgO, and polypropylene fiber, From the results of test, it was found that first addtivies -cement and beestar-was effective for compressive strength, and the resistance against freezing -thawing process was improved by secondary additives, in the order their effectiveness, i.e. CaSO4 , Synthetic fiber, MgO and Beestar.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.4
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• pp.270-278
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• 2005

Recycled aggregate concrete has lower strength and durability compared to concrete with natural aggregate. Therefore, metakaolin is used to improve the properties of recycled aggregate concrete. Main components of metakaolin are $SiO_2$ and $Al_2O_3$. and specific surface area is 9 times larger than that of ordinary portland cement. Quality of demolished-recycled aggregate(DRA) satisfies the type 1 of KS F 2573, but quality of source-recycled aggregate(SRA) does not satisfy with the type 2 of KS F 2573. When metakaolin was replaced with 20% of cement, compressive strength of concrete with SRA and DRA develops about 40~64% of control concrete. Water absorption ratio was reduced about 2% by replacing 20% metakaolin and it represents low compared to the natural aggregate concrete without metakaolin. In addition, the resistance to freezing and thawing, of concrete with DRA is indicated to remarkably enhanced due to the contribution of metakaolin. However, when metakaolin is replaced with 20% of cement, relative dynamic modulus of elasticity of concrete with SRA was below 60% at 210 freezing and thawing cycles.

• Food Science and Preservation
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• v.17 no.4
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• pp.478-486
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• 2010

The qualities of ginger prepared by an MPD (molecular press dehydration) method using maltodextrin, or dried using reused dehydration liquid, or prepared by freeze-drying or hot-air drying, were compared in terms of approximate overall composition, color, water absorption index, water solubility index, total sugar level, reducing sugar concentration, antioxidant activity, and gingerol content. The approximate composition of ginger prepared by the MPD method was lower in overall biochemical content than were those of gingers prepared using other methods. Ginger prepared by the MPD method retained the original ginger color. The water absorption and solubility index of ginger prepared by the MPD method (using maltodextrin) were better than those of gingers dried using other methods. The total sugar content did not change noticeably upon processing. The reducing sugar content of ginger prepared by hot-air drying was low. The antioxidant activity of ginger prepared by the MPD method was higher than that of freeze-dried and hot air-dried ginger samples, with values lower than those of BHA (3(2)-t-Butyl-4-hydroxyanisole) and BHT (2,6-Di-tert-butyl-4-methylphenol). The gingerol content of ginger prepared by the freeze-drying method was higher than that of gingers prepared by other methods. However, ginger constituents were present in the dehydration liquid used in the MPD method. The results indicate that both the MPD method (using maltodextrin) and the use of reused dehydration liquid are efficient methods by which ginger can be dried.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.2
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• pp.183-190
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• 2006

An experimental study was conducted to evaluate the effect of freezing-thawing and air pollutants on the weathering of $TiO_2$ loaded granite. And the granite was coated with $TiO_2$ catalyst and tested. After freezing-thawing and air pollutants experiments the mineral compositions of the granite surface were lower then that of the fresh granite. Density of the weathered granite was steadily decreased from $2.60g/cm^3\;to\;2.55{\sim}2.56g/cm^3$, but absorption ratio and porosity were slightly increased. From these results, it was expected that granite could be weathered by freezing-thawing md air pollutants. In the case of $TiO_2$ was coated to the granite, the compressive strength and absorption ratio were slightly enhanced compared to the $TiO_2$ non-coated granite. Therefore, the $TiO_2$ coating method tested in this study considered to be a viable method to assist in the conservation of granite from environmental contaminants.

• Microbiology and Biotechnology Letters
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• v.39 no.2
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• pp.153-160
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• 2011

In this study, we have developed taste and other functional enhancements of yam chips, from tasteless and flavorless yam slices, through the process of soaking freeze-dried yam in different commercially available juices, including apple, omija (fruit of Maximowiczia typica), grape, wild grape, orange, tomato, red ginseng, and black garlic juice. The analyses of color (brightness, redness and yellowness), pH, brix, acidity, total polyphenol, total flavonoids, total sugar and reducing sugar, DPPH and ABTS scavenging activity, reducing power and nitrite scavenging activity, of the different yam chips showed that the freeze-dried yam slices absorb various components of fruit juices, such as flavonoids, sugars, organic acids and flavors, during the soaking process. These changes resulted in increased taste (both sweet and sour tastes), flavor and antioxidant activity in the yam chips. The soaking time for yam slices in juice is considered to be a crucial factor for the taste and bioactivity of yam chips. In the case of grape juice-yam chips, which had the highest preference among the 8 different chips, the optimum soaking time was noted as 120 seconds. The optimization of the soaking process is necessary for various juices. These results suggest that taste, and other functional enhancements, in yam chips can be developed by juice-soaking and freeze-drying methods.

• The Korean Journal of Pesticide Science
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• v.14 no.3
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• pp.235-240
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• 2010

In order to elucidate residual characteristics of pesticides in garlic by drying, azoxystrobin and flutolanil used for garlic were treated to the garlic by dipping for 1 and 5 min into their standard diluents and then the garlic was dried with a freeze-drier. The test pesticides were analyzed with a GLC-ECD/NPD. Recoveries of the pesticides ranged from 81.96 to 98.18%. Amount of azoxystrobin and flutolanil in fresh garlic were 0.34 and 1.18 mg/kg in case of dipping for 1 min. and 0.44 and 2.15 mg/kg in case of dipping for 5 min., respectively. Also, amount of azoxystrobin and flutolanil in dried garlic were 0.80 and 4.51 mg/kg in case of dipping for 1 min. and 1.03, 5.28 mg/kg in case of dipping for 5 minute, respectively, representing that concentration of the test pesticides in garlic were increased by drying. In case of dipping for 1 and 5 min., processing factors of azoxystrobin were 2.35 and 3.34 and those of flutolanil were 1.19 and 1.17, respectively. Reduction factors of the pesticides in garlic were range from 0.94 to 0.97, indicating that few amounts of the test pesticides in garlic were dissipated by freeze-drying.

• Applied Chemistry for Engineering
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• v.7 no.1
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• pp.186-193
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• 1996

Several chitosan beads were prepared by W/O emulsion and capillary extrusion methods. The surface structures were observed through SEM pictures, the surface areas were determined by BET method, the available amine contents were measured by picric acid titration method, and the results were correlated each other. The beads from W/O emulsion method were smaller in size but had higher hardness, surface area, and available amine contents than the ones from capillary extrusion method. Moreover, the surface area, available amine contents, apparent density and the hardness showed large differences according to the drying processes. As compared between the solvent dehydration and the freeze drying technique in W/O emulsion method, the former showed higher surface area, higher available amine contents and hardness than the latter. SEM pictures revealed that in case of solvent dehydration method, very small pores existed, whereas in case of freeze drying method, cell-like pores existed on the surface. The results of picric acid titration showed that the beads dried by solvent dehydration method were 10 times higher in amine contents than those from freeze drying method, and the amount of amine contents were increased as the surface area was increased. After fluorescamine was reacted with chitosan beads, the fluorescence labeled beads were observed through fluorescence microscope. The results showed that most of primary amine existed on the surface of beads and pores.