• Title/Summary/Keyword: Moist test

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Correlation between Insulation Diagnostic Test and AC Breakdown Test for 3.3 kV Class Induction Motor

  • Byun, Doo-Gyoon;Hong, Jin-Woong
    • Transactions on Electrical and Electronic Materials
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    • v.7 no.5
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    • pp.262-266
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    • 2006
  • The insulation diagnostic test and the AC breakdown test were performed under off-line using the 3.3 kV class induction motor which have been served for 10 years. These tests were conducted in means of nondestructive and destructive test. In this paper, we compared the correlation between the nondestructive and destructive test. Furthermore we setup an experimental condition with moisture and compared the insulation characteristics between moist and dry sample. From the results of the nondestructive and destructive test, it was found that the second AC current, which is the previous step of insulation breakdown, suddenly increased at a point of around 8.5 kV. The insulation breakdown of moist sample occurred at 12-14 kV, which is 4-5 kV lower than dry sample.

A study on physical characteristics of cement mortar according to change of moist mud flat replacement ratio (습윤갯벌 치환율 변화에 따른 시멘트 모르타르의 물리적 특성에 관한 연구)

  • Yang, Seonghwan;Kang, Yunyoung;Lee, Heungyeol
    • Journal of the Society of Disaster Information
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    • v.13 no.3
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    • pp.348-357
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    • 2017
  • In this study, we examined the physical properties of cement mortar by replacing a part of the amount of fine aggregate in moist mud flat. I analyzed the possibilities of using bricks. Flow measurement results show that the flow value increases as the mixing ratio of cement and fine aggregate increases and the flow value decreased as the replacement ratio of moist mud flats decreased. Chloride contents were also found to decrease with decreasing substitution rate of moist mud flats. As a result of the compressive strength measurement, the compressive strength increased in inverse proportion as the displacement ratio of moist mud flats decreased in most mixing ratio. As a result of tensile strength measurement, the tendency was similar to compressive strength and the intensity increased as the replacement ratio of moist mud flats decreased.

P-value significance level test for high-performance steel fiber concrete (HPSFC)

  • Abubakar, Abdulhameed U.;Akcaoglu, Tulin;Marar, Khaled
    • Computers and Concrete
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    • v.21 no.5
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    • pp.485-493
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    • 2018
  • Statistical analysis has found useful application in the design of experiments (DOE) especially optimization of concrete ingredients however, to be able to apply the concept properly using computer aided applications there has to be an upper and lower limits of responses fed to the system. In this study, the production of high-performance steel fiber concrete (HPSFC) at five different fiber addition levels by volume with two aspect ratios of 60 and 83 were studied under two curing methods completely dry cured (DC) and moist cured (MC) conditions. In other words, this study was carried out for those limits based on material properties available in North Cyprus. Specimens utilized were cubes 100 mm size casted and cured for 28 days and tested for compressive strength. Minitab 18 statistical software was utilized for the analysis of results at a 5 per cent level of significance. Experimentally, it was observed that, there was fluctuation in compressive strength results for the two aspect ratios and curing regimes. On the other hand P-value hypothesis evaluation of the response showed that at the stated level of significance, there was a statistically significant difference between dry and moist curing conditions. Upper and lower limit values were proposed for the response to be utilized in DOE for future studies based on these material properties. It was also suggested that for a narrow confidence interval and accuracy of the system, future study should increase the sample size.

Time-dependent Behaviors of Concrete Exposed in the 100% Relative Humidity (상대습도 100% 환경에 노출된 콘크리트의 시간 의존적 거동)

  • Min, Kyung-Hwan;Kim, Youl-Hee;Jung, Hyung-Chul;Yoon, Young-Soo
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.693-696
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    • 2008
  • In order to assess time-dependent behaviors of the high-strength concrete that applied in actual FCM bridges with various curing environments, the shrinkages of air-dried, sealed, and moist 100${\times}$100${\times}$400 mm prism specimens were measured. And the compressive creep test of 3 and 28 days aged concrete in the tap water and 10% CaCl$_2$ solutions were carried out, then results were compared with traditional test results of air-dried and sealed specimens. Time-dependent behaviors of the concrete that according to curing circumstances between sealed and moist specimens show remarkable differences not only on the shrinkage but also on the creep. Hence there need some reconsiderations to the traditional creep test manners that predicting the creep and shrink age of actual concrete structures.

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The Study of Restoration Technique of Wax-Treated Volume for the Annals of the Joseon Dynasty (III) -Evaluation of Durability of Korean Traditional Paper using Moist-heat Aging Treatment- (조선왕조실록 밀랍본 복원기술 연구(제3보) -습열열화처리를 이용한 복원용 한지의 내구성 평가-)

  • Jeong, Seon-Hwa;Jeong, Sun-Young;Seo, Jin-Ho;Jeong, So-Young
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.45 no.5
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    • pp.49-55
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    • 2013
  • To explore the paper materials for restoration of the Annals of the Joseon Dyansty, durability of the three type of the traditional Korean Papers were estimated in this study, through moist heat artificial aging test. Three types(D, F, and G) which showed the best preservation performance in dry heat and UV treatment in the previous study were selected and artificial accelerated aging treatment with moist-heat process was conducted; the viscosity change rate was D>G>F; folding endurance G>D>F; $L^*$ value F>D>G; $a^*$ and $b^*$ change rate D>G>F; brightness decrease rate D>G>F, suggesting paper F showed the least change rate in physical/optical properties. Also the CLSM image observation showed fair coherence among fibers and confirmed paper mulberry. And in FDI extraction from each sample, paper F showed the highest value. Overall, paper F (traditional glossy paper) showed the highest stability against thermal treatment. It confirms that paper F is suitable as restoration paper for tributary remains including the annals of the Joseon Dynasty for its steady strength/viscosity decrease rate and color change rate.

A Study on the Effects of System Pressure on Heat and Mass Transfer Rates of an Air Cooler

  • Jung, Hyung-Ho
    • Journal of Mechanical Science and Technology
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    • v.16 no.5
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    • pp.696-702
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    • 2002
  • In the present paper, the effects of inlet pressure on the heat and mass transfer rates of an air cooler are numerically predicted by a local analysis method. The pressures of the moist air vary from 2 to 4 bars. The psychrometric properties such as dew point temperature, relative humidity and humidity ratio are employed to treat the condensing water vapor in the moist air when the surface temperatures are dropped below the dew point. The effects of the inlet pressures on the heat transfer rate, the dew point temperature, the rate of condensed water, the outlet temperature of air and cooling water are calculated. The condensation process of water vapor is discussed in detail. The results of present calculations are compared with the test data and shows good agreements.

Protective Effect of Ag Coated on Textured YBCO Surface

  • Soh, Daewha;Shan, Yuqiao;Fan, Zhanguo
    • Proceedings of the Materials Research Society of Korea Conference
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    • 1996.11a
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    • pp.171-173
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    • 1996
  • Ag coating on the textured YBCO was prepared by means of a Ag$_2$O brushed coating method. The contact between Ag coating and textured YBCO was examined by sharp knife cut and by the observation of SEM. The critical current densities of different textured YBCO samples, which included YBCO with and without Ag coating, and YBCO with Ag coating after hot moist text, were compared. The Ag coating does not influence the oxygen absorption of textured YBCO, but Ag coating can protect YBCO well from moisture and $CO_2$

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Dentin moisture conditions strongly influence its interactions with bioactive root canal sealers

  • Ozlek, Esin;Gunduz, Huseyin;Akkol, Elif;Neelakantan, Prasanna
    • Restorative Dentistry and Endodontics
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    • v.45 no.2
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    • pp.24.1-24.9
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    • 2020
  • Objectives: It is known that bioactive materials interact with the dentin to undergo biomineralization. The exact role of moisture in this interaction is unknown. Here, we investigate the effects of dentin moisture conditions on the dislocation resistance of two bioactive root canal sealers (MTA Fillapex [Angelus Solucoes Odontologicas] and GuttaFlow BioSeal [Colténe/Whaledent AG]) at 3 weeks and 3 months after obturation. Materials and Methods: Mandibular premolars (n = 120) were prepared and randomly divided into 3 groups based on the dentin condition: group 1, dry dentin; group 2, moist dentin; group 3, wet dentin. Each group was divided into 2 subgroups for root canal filling: MTA Fillapex and GuttaFlow BioSeal. Dislocation resistance was evaluated by measuring the push-out bond strength at 3 weeks and 3 months. Failure modes were examined under a stereomicroscope. Data were statistically analyzed by Kruskal-Wallis test with a significance level of 5%. Results: Moist dentin resulted in higher bond strength values for both materials at both time points. This was significantly higher than wet and dry dentin for both the sealers at the 3 months (p < 0.05), while at 3 weeks it was significant only for GuttaFlow Bioseal. The different moisture conditions demonstrated similar trends in their effects on the dislocation resistance of the 2 root canal sealers. Conclusions: The dentin moisture conditions had a significant impact on its interaction with the bioactive materials tested. Maintaining moist dentin, but not dry or wet dentin, may be advantageous before the filling root canals with bioactive sealers.

Surface Protection of YBCO Superconductors (YBCO초전도체의 표면보호에 관한연구)

  • Shan Yuqiao;Du Jinhong;Soh Daewha;Fan Zhanguo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1996.11a
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    • pp.249-251
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    • 1996
  • Ag coating on the textured YBCO and PTFE coating on the sintering YBCO were prepared. The critical current densities of different YBCO samples with and without coatings were compared. Both of Ag coating and PTFE coating can well protect YBCO from moisture and $CO_2$.

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A Study on the Predictability of Moist Convection during Summer based on CAPE and CIN (대류가용잠재에너지와 대류억제도에 입각한 여름철 습윤 대류 예측성에 대한 연구)

  • Doyeol Maeng;Songlak Kang
    • Journal of the Korean earth science society
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    • v.44 no.6
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    • pp.540-556
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    • 2023
  • This study analyzed rawinsonde soundings observed during the summer and early fall seasons (June, July, August and September) on the Korean peninsula to examine the utility of the Convective Available Potential Energy (CAPE) and Convective Inhibition (CIN) in predicting the occurrence of deep moist convection and precipitation. Rawinsonde soundings are categorized into two groups based on thermodynamic criteria: high CAPE and low CIN represent a high potential for deep moist convection; low CAPE and high CIN indicate conditions unfavorable for deep convection. A statistical hypothesis test is conducted to determine whether the two groups are significantly different in terms of 12-hour cumulative precipitation, 12-hour mean cloud base, and 12-hour mean mid-level cloud cover. The results, in the case of no-precipitation, reveal statistically significant differences between the two groups, except for the 12-hour mean cloud base during the 21:01-09:00 KST time period. This suggests that the group characterized by high CAPE and low CIN is more conducive to the occurrence of deep moist convection and precipitation than the group with low CAPE and high CIN.