• Title/Summary/Keyword: Freezing method

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Study for Dynamic Modulus Change Measurement of Permeable Asphalt Mixtures with Various Porosity using Non-Destructive Impact Wave (충격공진시험을 이용한 다양한 공극률을 가진 투수성 아스팔트 혼합물의 동탄성계수 변화 측정에 관한 연구)

  • Jang, Byung Kwan;Yang, Sung Lin;Mun, Sung Ho
    • International Journal of Highway Engineering
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    • v.15 no.3
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    • pp.65-74
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    • 2013
  • PURPOSES: This study is to evaluate the dynamic modulus changes of permeable asphalt mixtures by using non-destructive impact testing method and to compare the dynamic moduli of permeable asphalt mixtures through repeated freezing and thawing conditions. METHODS: For the study, non-destructive impact testing method is used in order to obtain dynamic modulus of asphalt specimen and to confirm the change of dynamic modulus before and after freezing and thawing conditions. RESULTS : This study has shown that the dynamic moduli of asphalt concrete specimens consisting of 10%, 15% and 20% porosity are reduced by 11.851%, 1.9564%, 24.593% after freezing and thawing cycles. CONCLUSIONS : Non-destructive impact testing method is very useful and has repeatability. Specimen with 15% porosity has high durability than others.

A Numerical Study on the Phase-change Heat transfer problem in Cryosurgery (냉동수술시 수반되는 상변화 열전달 문제에 대한 수치해석적 연구)

  • 김동혁
    • Journal of Advanced Marine Engineering and Technology
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    • v.20 no.3
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    • pp.162-170
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    • 1996
  • A numerical study on the Stefan problem occurred in cryosurgery is performed. Crank-Nicholson type finite difference algorithm based on the enthaly method is adapted to solve the phase change problem in this study. As it is a moving boundary problem, special emphasis is put on the estimation of the freezing front location. Two cases selected here are freezings of human tissue by disk type cryoprobe and by hemispherical one. In both cases, the heat flows are considered to be one dimensional. The calculated results using enthalpy method are compared with those using the program TRUMP and with Neumann's solution. These results agree guite well with each other. While it is pretty difficult to get accurate freezing front location by TRUMP due to the so- called "phase change knee" occured during the phase change, the algorithm based on the enthalpy method is proved to be very powerful to cope with this kind of problem.f problem.

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Pheophytin Content and Cytotoxicity of Silkworm Feces Against Jurkat Cells According to Dry Method and Storage Period

  • Ahn, Mi-Young;Kim, Iksoo;Ryu, Kang-Sun;Kim, Jin-Won;Lee, Heui-Sam;Lee, Pyeong-Jae;Ko, Si-Hwan;Lee, Won-Young
    • International Journal of Industrial Entomology and Biomaterials
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    • v.8 no.2
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    • pp.135-138
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    • 2004
  • In order to find potential anticancer agents, we extracted pheophytin from silkworm feces according to various dry and storage methods such as sun dry, shade dry, fresh freezing dry and freezing dry after freezing storage (for 1∼3 years). The pheophytin extracts, mainly 10-hydroxypheophytin a, little b, of various storage silkworm feces were analyzed by reversed-phase high-performance liquid chromatography with photodiode array and fluorescence detection. The content of those pheophytih in old silkworm for 3 years (freezing storage and freezing dried in use, or freezing dried and cold storage) was better than others. The cytotoxicity of the pheophytin extracts and ethanol extracts of various storage silkworm feces were measured using Jurkat cells originated from human leukemia, using dye uptake assay (MTT) in order to find effective photodynamic therapeutic agents. The anticancer activity of those pheophytin extracts in various storage methods showed little difference among them. But ethanol extracts of fresh freezing dried silkworm in the current year was good cytotoxic activity than those of any other silkworm feces. With regards to these results, fresh ethanol extracts of silkworm feces were better than old ones. On the other hands, the pheophytin extracts of old silkworm feces contained the highest percentage of pheophytin content and showed good cytotoxicity against cancer cells by changing the pheophytin into pheophobide in the degradative process.

A Study on the Effects of Cryopreservation by One-Step Straw Method on the Survival of Bovine Embryos (1단계 straw동결법이 소 수정란의 생존성에 미치는 영향에 관한 연구)

  • 김상근;김무강
    • Journal of Embryo Transfer
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    • v.9 no.1
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    • pp.65-71
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    • 1994
  • This study were carried out to investigate the effective concentration of cryoprotectant agents and sucrose by one-step straw method, and to determine the optimum thawing temperature and equilibration time of frozen bovine embryos. The bovine embryos following dehydration by cryoprotective agents and a various concentration of sucrose were directly plunged into liquid nitrogen and thawed in 3O$^{\circ}C$ water. Survival rate was defined by FDA test. The results are summarized as follows : 1. The survival rate of bovine embryos thawed after rapid freezing in the freezing medium containing a various kinds of cryoprotective agents added 0.25M and O.50M sucrose were 28.6% and 25.0%, 35.1% and 31.6%, 32.4% and 24.4%, 34.2% and 28.2%, 18.9% and 17.6%, 14.7.% and 21.6%, respectively. 2. The survival rate of bovine embryos thawed after rapid freezing in the freezing medium containing a various concentration of sucrose added 1.5M and 2.OM glycerol, i.5M and 2.OM DMSO and 1.5M and 2.OM propanediol were 22.9~37.8%, 2O.7~31. 3%, 19.2~30.0% and 17.2~25.0%, respectively. 3. The temperature thawed at 2$0^{\circ}C$ after rapid freezing of bovine embryos resulted in a significantly higher embryos survival rate than did at 3$0^{\circ}C$ and 35$^{\circ}C$. 4. The equilibration time on the survival rate of bovine embryos was attained after short period of time(2.5~5 min.) in the freezing medium higher than long period of time (1O~20 min.).

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Study on temperature characteristics in depth of concrete pavement for development of prediction method of road surface freezing (노면결빙 예측기법 개발을 위한 콘크리트 포장의 깊이별 온도특성 연구)

  • Kim, Jong-Woo;Kim, Ho-Jin
    • Proceedings of the Korea Concrete Institute Conference
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    • 2010.05a
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    • pp.391-392
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    • 2010
  • The frozen road is effected as major cause of car accident in winter. Especially, road surface freezing on the highway can lead to fatal accident. The accident by frozen road can effectively reduced by prevent road surface freezing before it frozen as evaluate road surface condition. Therefore, this study installed thermometer in each depth of concrete pavement for evaluate road surface conditions which freezing chronically. The result of this study will be used as preliminary data for predict before freezing.

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Freshness Changes during Iced and Partial Freezing Storage of Sashimi (생선회용 어육의 냉장 및 Partial Freezing 저장중 선도의 변화)

  • 김복자
    • Journal of the Korean Home Economics Association
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    • v.18 no.4
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    • pp.87-94
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    • 1980
  • This study was carried out to make a comparison between iced and partial freezing of bastard, yellow tail, poragy, pomfret that were generally used for Sashimi and the results that measured k-value, VB-N, TMA-N were measured and the results are as follows : 1. Regardless of the kinds of fish, freshness is better preserved in partial freezing than in iced storage. 2. In Bastard, Yellow tail When iced its freshness estimation index its K-value rose above 20% after 4 days of storage. When stored partially frozen, its K-value reached 20% after 8 days. 3. Porgy when iced, its K-value reach 20% after 6 days of storage. But when stored partially frozen, its K-value could be prolonged until 9 days with same degree. Porge was preserved for the longest time among the four fishes. 4. Pomfret When iced during 4 days and stored partially frozen during 6 days, their K-value reached about 20% Pomfret was preserved for the shortest time among the four fishes. 5. According to the kinds of fish, the results that measured VB-N, TMA-N, total bacteria have some differences, but the method of partial freezing was superior to iced storage.

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Frost Heaving Pressure Characteristics of Frozen soils with Frost-Susceptibility and Degree of Saturation (흙의 동상민감성과 포화도를 고려한 동상팽창압 특성)

  • 신은철;박정준;김종인
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.329-336
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    • 2002
  • The earth structures and in-ground LNG tank, and buildings can be constructed with using artificial freezing method on the reclaimed land. In this study, upon freezing a saturated soil in a closed-system from the top, a considerable pressure was developed. The pressure is the result of the surface energy of a curved ice-water interface. The most significant of these parameters will have the greatest effect on the classification. In order to establish frost-susceptibility criteria based on frost heaving expansion pressure, more soils have to be tested. This study was initiated to investigate the soils frost heaving expansion pressure and moisture characteristics resulting from freezing and freezing-thawing cycle process. Weathered granite soils, sandy soil, sandy soil were used in the laboratory freezing test subjected to thermal gradients under closed- systems.

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The design concept of the cubicle to improve freezing performance for high speed train (고속열차 배전반의 냉각성능 신뢰성 향상 방법에 대한 연구)

  • Choi, Kwon-Hee;Jeong, Byung-Ho;Lee, Byung-Seok;Park, Jong-Hun;Lee, Jong-Woo
    • Proceedings of the KSR Conference
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    • 2007.05a
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    • pp.905-910
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    • 2007
  • The cubicle of high speed train is the equipment where the important train- operating equipments are concentrated, so it requires the higher safety and reliability than any other equipment. Recently, the power car cubicle of KTX-II is, basically similar to that of KTX-I and HSR350x in its size, but consequently, as more sophisticated ATP/ATC and other parts are added, the order company points out the problem of rising temperature in summer. Especially, the interpretation about the possibility of guaranteeing the minimum freezing performance becomes necessary, when Fan Tray is out of order. This paper presents the method of improving the freezing performance while minimizing the effect of dust, and the method of guaranteeing the present freezing performance by the best arrangement of Fan Tray, when Fan Tray is out of order. And as a method of verifying this, we would like to predict the pressure, speed of a running fluid and temperature distribution of cubicle through the flow analysis.

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Rapid Determination of Chlorostyrenes in Fish by Freezing-Lipid Filtration, Solid-Phase Extraction and Gas Chromatography-Mass Spectrometry

  • Kim, Min-Sun;Park, Kwang-Sik;Pyo, Hee-Soo;Hong, Jong-Ki
    • Bulletin of the Korean Chemical Society
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    • v.29 no.2
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    • pp.352-356
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    • 2008
  • An analytical method has been developed for measuring chlorostyrenes in fish tissue sample. Extraction of chlorostyrenes from fish tissue was carried out by ultrasonication using acetone/n-hexane (5:2, v/v) mixture. Most of the lipids in the extract were eliminated by freezing-lipid filtration, prior to solid-phase extraction (SPE) cleanup. During freezing-lipid filtration, about 90% of the lipids extracted from the fish samples were easily removed without any significant losses of chlorostyrenes. For purification, SPE using Florisil was used for the rapid and effective cleanup. Quantification was performed using gas chromatography-mass spectrometry in the selected ion monitoring mode. Spiking experiments were carried out to determine the recovery, precision, and limits of detection (LODs) of the method. The overall recovery was above 80% in the spiked fish tissue sample at 10 and 100 ng/g levels, respectively. The detection limits for chlorostyrenes were ranged from 0.05 to 0.1 ng/g. This developed method is demonstrated to give efficient recoveries and LODs for detecting chlorostyrenes spiked into fish tissue with high lipid content.

Gilt Transfer of Cultured Freezing Embryos by Open Pulled Straw(OPS) Methods (Open Pulled Straw(OPS) 방법에 의한 체외 배양 동결 수정란의 미경산돈 이식)

  • Kim, In-Doc;Seok, Ho-Bong
    • Journal of Embryo Transfer
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    • v.23 no.3
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    • pp.217-222
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    • 2008
  • In previous studies, we reported that sow which was transferred OPS-freezing embryos not able to deliver a piglet (Kim et al, 2004). This study was conducted to investigate a possibility of gilt as recipients which produce piglets after transfer of OPS-freezing embryos. All transferred embryos were prepared by in vitro production (IVP) system. In vitro culture (IVC) medium used glucose-free NCSU23 supplemented with 5mM sodium pyruvate, 0.5 mM sodium lactate and 4 mg/ml bovine serum albumin for 2 days at $39^{\circ}C$. From day 3 of IVC, 10% fetal bovine serum albumin was added to the culture medium. In preparing of freezing embryos, embryos were treated with 7.5 $\mu g/ml$ cytochalasin-B for 30 min and centrifuged at $13,000{\times}g$ for 13 min. And then, embryos were exposed sequentially to an ethylene glycol (EG) solution, aspirated into open pulled straw (OPS), and plunged or thawed into the liquid nitrogen. In embryo transfer (ET), we used two kinds of type (surgical method vs. non-surgical method). In surgical method of embryo transfer, $55\sim65$ embryo were transferred in both uterine horn of two recipient gilts by plastic straw. Non-surgical method which is like artificial insemination was performed on three gilts. Each 140 frozen embryos were transferred to two gilts and 40 fresh embryos to one gilt. Pregnancy establishment was shown one recipient at 45 days after ET. However, the one recipient was also aborted at 58 days after ET. These results suggest that gilts can be considered as a candidate of recipients for OPS-freezing embryo transfer.