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The Properties of Rheology of Underwater-Hardening Epoxy Resin According to the Temperature and Hardener Ratio (온도 및 경화제 비율에 따른 수중경화형 에폭시수지의 레올로지 특성)

  • Jung Eun Hye;Kwag Eun Gu;Lee Dae Kyung;Cho Sung Hyun;Bae Kee Sun;Kim Jin Man
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.11a
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    • pp.761-764
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    • 2005
  • Epoxy resin, as no-hardening, applied for repair and finish materials is used to mix together with hardener. It is advantages that epoxy resin has reaction shrinkage less than other materials and has excellent in water proofing, thermal resistance. The other hands, because ratio of combination of epoxy resin and hardener is fixed, it is not possible to change according to field condition. This investigated suspended time by temperature and hardener ratio. As a results of study, it can select economical ratio of the epoxy resin and hardener according to site situation.

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Study on the Properties of Dam Concrete Using Low Heat Portland Cement (저열 포틀랜드 시멘트를 사용한 댐 콘크리트의 특성에 관한 연구)

  • Son, Young-Jun;Ha, Jae-Dam;Um, Tai-Sun;Lee, Jong-Ryul;Kim, Tae-Hong
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.05b
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    • pp.445-448
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    • 2006
  • In order to control the temperature crack of massive dam concrete, the selection of appropriate materials like binder, aggregates etc., is essential. To select the optimal mix proportion, ordinary portland cement(Type I) plus 25% of fly ash and low heat portland cement(Type IV) are used as binder, and 80mm of coarse aggregates are used to reduce the amount of binder and compare the compressive strength, hydration temperature and crack index. The results of this study are as following. 1. The strength of Type IV cement is advantageous on the long-term age. 2. According to the temperature measured on mock-up$(1.5m{\times}1.5m{\times}1.5m)$, and realized the thermal analysis, the Type IV cement carried out advantageous to control the thermal crack.

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A Statistical Matching Method with k-NN and Regression

  • Chung, Sung-S.;Kim, Soon-Y.;Lee, Seung-S.;Lee, Ki-H.
    • Journal of the Korean Data and Information Science Society
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    • v.18 no.4
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    • pp.879-890
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    • 2007
  • Statistical matching is a method of data integration for data sources that do not share the same units. It could produce rapidly lots of new information at low cost and decrease the response burden affecting the quality of data. This paper proposes a statistical matching technique combining k-NN (k-nearest neighborhood) and regression methods. We select k records in a donor file that have similarity in value with a specific observation of the common variable in a recipient file and estimate an imputation value for the recipient file, using regression modeling in the donor file. An empirical comparison study is conducted to show the properties of the proposed method.

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Physicochemical and Sensory Characteristics of Brown Sauce made with Pork Bone (돼지뼈를 이용한 갈색육수 소스의 이화학적 및 관능적 특성)

  • Kim, Yong-Sik;Song, Chung-Rak
    • Culinary science and hospitality research
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    • v.7 no.1
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    • pp.119-133
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    • 2001
  • The purpose of this study was to investigate the sensory and physicochemical properties of brown sauce made with different kind of bone(beef bone, pork bone). For this purpose, the various methods and recipe of brown sauce appeared in the literatures were evaluated to select the most preferable brown sauce. Brown sauces made with pork bone, beef and pork bone showed negative value in the "a" value (redness). Viscosity of brown sauce made with pork bone was the highest as well as the brown stock. The sensory tests of brown sauce showed no significant difference between each groups except flavor at p<0.001.

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The Characteristic Investigation on Narrow-gap TIG Weld Joint of Heavy wall Austenitic Stainless Steel Pipe (오스테나이트계 SS 배관의 협개선 TIG 용접부 특성 조사)

  • Shim, Deog-Nam;Jung, In-Cheol
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.670-677
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    • 2003
  • Although Gas Tungsten Arc Welding (GTAW or TIG welding) is considered as high quality and precision welding process, it also has demerit of low melting rate. Narrow-gap TIG welding which has narrow joint width reduces the groove volume remarkably, so it could be shorten the welding time and decrease the overall shrinkage in heavy wall pipe welding. Generally Narrow-gap TIG welding is used as orbital welding process, it is important to select the optimum conditions for the automatic control welding This paper looks at the application and metallurgical properties on Narrow-gap TIG welding joint of heavy wall large austenitic stainless steel pipe to determine the deposition efficiency, the resultant shrinkage and fracture toughness. The fracture toughness depends slightly on the welding heat input.

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Pervaporation separation of ethanol via adsorbent-filled silicon rubber membranes

  • Ji, Ling-Yun;Shi, Bao-Li;Wang, Qing-Wen
    • Membrane and Water Treatment
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    • v.5 no.4
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    • pp.265-279
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    • 2014
  • Pervaporation is the most promising technique for the recovery of ethanol from the fermentation system. To date, extensive research has been conducted on the exploration of membrane materials with favorable properties. In this paper, we primarily review the performance of adsorbent-filled rubbery membranes. In addition, the fundamental mechanisms of ethanol and water molecules transportation through composite membranes are demonstrated, particularly from the perspective of cluster formation. Finally, future prospects are also analyzed to develop the guidelines for the future development of excellent membrane materials for ethanol concentration. This paper is not meant to be an exhaustive overview, rather a specialized summary that allows readers to select the information appropriated to their topics.

A Photometric Study of Five Open Clusters in the SDSS

  • Ryu, Jin-Hyuk;Lee, Myung-Gyoon
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.2
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    • pp.81.1-81.1
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    • 2010
  • We present a study of five open clusters (Alessi 53, Berkeley 49, Berkeley 84, Czernik 5, Pfleiderer 3) based on ugriz images of the Sloan Digital Sky Survey (SDSS). Physical properties of these clusters are not yet well known. The center and size of these clusters are determined using the radial number density profile. Using the proper motion data, we select the members of the target clusters. We estimate physical parameters of the clusters based on the isochrone fitting in the Color-Magnitude Diagram (CMD) : reddening, distance, and age. The foreground reddening is determined to be E(B-V)=0.71-1.55 mag. The distances to target clusters are derived to be 2.0-4.4 kpc, corresponding to the galactocentric distances of 7.5-11.9 kpc. Their ages are in the range of 280 to 1000 Myr. Their spatial distribution in our Galaxy is similar to that of other intermediate-age open clusters. We find ten blue straggler star candidates in Berkeley 49. This number of blue stragglers is a typical value for the age of Berkeley 49.

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Experimental Study Mixing, Placing and Hydration Temperature of 1400kg/$\textrm{cm}^2$ Ultra High-Strength Concrete (1400kg/$\textrm{cm}^2$ 초고강도 콘크리트의 배합, 타설 및 수화온도 이력에 관한 연구)

  • 윤영수;장일영;원종필;최응규
    • Proceedings of the Korea Concrete Institute Conference
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    • 1997.10a
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    • pp.430-435
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    • 1997
  • This paper presents the material properties and production of 1400kg/$\textrm{cm}^2$ ultra high-strength concrete in consideration of the history of hydration temperature for the practical utilization. A series of laboratory tests were conducted to optimize the mix proportion and then the full-scall mock up tests were performed to investigate the practicability. The thermal sensors were installed prior to concrete casting into the walls and columns, to measure the hydration temperature during the hardening process, which is inevitable to select the most appropriate curing scheme.

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A Numerical Approach to Indentation Techniques for Thin-film Property Evaluation (박막 물성평가 압입시험의 수치접근법)

  • Lee, Jin-Haeng;Yu, Han-Suk;Lee, Hyung-Yil
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.31 no.3 s.258
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    • pp.313-321
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    • 2007
  • In this work, the prior indentation theory for a bulk material is extended to an indentation theory for evaluation of thin-film material properties. We first select the optimal data acquisition location, where the strain gradient is the least and the effect of friction is negligible. A new numerical approach to the thin-film indentation technique is then proposed by examining the finite element solutions at the optimal point. With this new approach, from the load-depth curve, we obtain the values of Young's modulus, yield strength, strain-hardening exponent. The average errors of those values are less than 3, 5, 8% respectively.

Isolation and Identification of Acid- and Bile-Tolerant Lactobacillus salivarius subsp. salivarius from Human Faeces

  • Bae, Hyoung Churl;Choi, Seong Hyun;Nam, Myoung Soo
    • Asian-Australasian Journal of Animal Sciences
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    • v.14 no.8
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    • pp.1170-1178
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    • 2001
  • This study was conducted to isolate lactobacilli having characteristics to be used as health adjuncts with fermented milk products. Acid tolerant strains were selected in Lactobacilli MRS broth adjusted to pH 4.0 from human faeces. Bile tolerant strains were examined in Lactobacilli MRS broth in which 1.0% bile salt was added. Microhemagglutination tests using swine erythrocytes were performed to select lactobacilli having adherence properties to survive in the intestinal tract. By examination of these characteristics the strain Nam 27, which was isolated from adult faeces, was selected and identified as Lactobacillus salivarius subsp. salivarius based on carbohydrate fermentation and 16S rDNA sequencing.