• Title/Summary/Keyword: Comparison Test

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Consideration of Geosynthetics Chemical Resistance Test for Long-Term Performance Evaluation (장기성능 평가를 위한 토목섬유 화학저항성 시험 고찰)

  • Jeon, Han-Yong;Jang, Yeon-Soo;Gong, Hak-Bong
    • Proceedings of the Korean Geotechical Society Conference
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    • 2009.03a
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    • pp.222-232
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    • 2009

  • In this study, the real site test conditions were considered and applied to suggest the improved test method for geosynthetics chemical resistance. For this, index and performance tests were done to specify and regulate the more approached test method. Accelerated model by Arrhenius equation was applied to interpretate the experimental data. Through analysis and comparison the overall experimental results, we could suggest the possibility and setup the advanced chemical resistance test method for geosynthetics.

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Comparison and Evaluation of Load Test Methods for Aluminum Car Body (알루미늄 차체 하중 시험 방법에 관한 비교 평가)

  • 서승일;박춘수;신병천
    • Journal of the Korean Society for Railway
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    • v.7 no.1
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    • pp.32-36
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    • 2004

  • Aluminum carbody for rolling stocks is light and perfectly recycled, but includes severe defects which are very dangerous to fatigue strength. Static load test has been performed up to date to assess structural safety of the carbody. However, static load test is not sufficient to evaluate fatigue strength of the carbody, because fatigue failure is caused by dynamic load. In this study, the established load test methods for carbody are described and the characteristics of the methods are discussed. Also, a testing method to simulate dynamic loading condition is proposed for evaluation of fatigue strength of the carbody. The results by the proposed testing method are compared with the results by the static load test and new findings are discussed.

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Statistical Issues in the Articles Published in the Journal of Veterinary Clinics (한국임상수의학회지에 발표된 논문의 통계분석 검토)

  • Pak, Son-Il;Oh, Tae-Ho
    • Journal of Veterinary Clinics
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    • v.27 no.2
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    • pp.170-174
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    • 2010

  • With the ease availability of statistical software and powerful computers the application of statistical methods in domestic veterinary journals is on the increase. In parallel with this benefit, statistical errors are not uncommon even in renowned scientific and medical journals. These errors may lead to misinterpretation of the data, thereby, subjected to faulty conclusions. A systematic review of articles published in 8 issues of the Journal of Veterinary Clinics during 2006-2007 was performed to assess the statistical methodology and reporting. Ninety-four (72.9%) articles of the 129 original articles screened included any inferential statistical analysis in the article, including comparison of 3 or more groups (53 or 56.4%), comparison of independent 2 groups (40 or 42.6%), and paired t-test (9 or 9.6%) in order. Of the 94 articles in which statistical analysis was done 62 (or 66.0%) had at least 1 statistical error. Errors included failure to apply or incorrectly applying independent Student's t-test for paired data or vice versa, inappropriate use of t-test for more than 3 groups and failure in chi-square test to consider continuity-correction for small expected frequencies. The common errors in ANOVA were failure to validate assumption of the test, inappropriate post-hoc multiple-comparison and incorrect assumption of independence of data in repeated measures design. Reporting errors included failure to state statistical methods and failure to state specific test if more than 1 test was done. It is suggested that an editorial effort would be necessary to achieve the improvement of appropriate statistical procedures through the publication of statistical guidelines to author(s).

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Comparison of Test Methods for Evaluation of Chloride Diffusion Coefficient in Concrete (콘크리트의 염소이온 확산계수 평가를 위한 시험방법 비교)

  • Lee, Chan-Young;Kim, Hong-Sam;Kim, Jin-Cheol;Cheong, Hai-Moon;Ahn, Tae-Song
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.581-584
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    • 2008

  • Generally, durability of concrete structures under marine environment is grossly declined by detrimental ions such as chlorides, which penetrate concrete and was diffused to corrode reinforcing rod. Therefore, chloride diffusion properties in concrete are important for durability evaluation and design of concrete structure. For estimation of chloride diffusion coefficient in concrete, both evaluation methods are used for steady state and non-steady state derived from Fick's 1st and 2nd law, respectively. However, as it is very difficult to evaluate diffusion coefficient for non-steady state like service environment where concrete is actually exposed, indirect evaluation method by laboratory accelerated test is generally used. In this study, comparison of chloride diffusion behavior was investigated for fixed mix proportion and age of concrete using four accelerated test methods based on domestic and foreign standards. From test results, only relative comparison between concrete mixtures was possible using ASTM C 1202 test, and diffusion coefficient for steady state was estimated as low as 1/10 of that for non-steady state. In addition, diffusion coefficient estimated by immersion test was similar to result by NT build 492 test.

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