• Title/Summary/Keyword: Gap Test

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A Study on Comparison of Excellence Among of P-Model, E-Model, and GAP-Model

  • Cho, Yoon-Shik;Doh, Min-Sun
    • Journal of the Korean Data and Information Science Society
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    • v.19 no.3
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    • pp.893-901
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    • 2008
  • The disconfirmation paradigm is the earliest researched and the most deeply researched of all the paradigms in marketing. Disconfirmation paradigm deals with the influence of expectation, perceived product performance, and the discord between the two on consumer satisfaction. The GAP-Model is based on the disconfirmation paradigm that tries to understand the effect of the gap between before purchase expectations and after purchase perceptions of the product performance on dependent variables such as customer satisfaction. The purpose of this research is to test whether regression coefficients of a P-Model(performance only model), an E-Model(expectation only model) and GAP(P-E)-Model are equivalent in explaining service value and loyalty. The Chow's F-Test is used to test the excellence of the 3 models. As a result of comparison and analysis, P-Model showed more excellence of service value and loyalty than E-Model or GAP-Model.

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A Study on Shock-induced Detonation in Gap Test (충격 전달에 의한 Gap Test의 폭굉 반응 해석)

  • Kim, Bohoon;Kang, Wonkyu;Jang, Seung-gyo;Park, Jungsu;Yoh, Jai-ick
    • Journal of the Korean Society of Propulsion Engineers
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    • v.20 no.2
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    • pp.75-85
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    • 2016
  • A pyrotechnic system consisting of donor/acceptor pair separated by a gap relies on shock attenuation characteristics of the gap material and shock sensitivity of the donor and acceptor charges. Despite of its common use, numerical study of such pyrotechnic train configuration is seldom reported because proper modeling of the full process requires precise capturing of the shock wave attenuation in the gap prior to triggering a full detonation of high explosive and accurate description of the high strain rate dynamics of the explosively loaded inert confinements. We apply a Eulerian level-set based multimaterial hydrocode with reactive flow models for pentolite donor and heavily aluminized RDX as acceptor charge. The complex shock interaction, critical gap thickness, acoustic impedance, and go/no-go characteristics of the gap test are quantitatively investigated.

Effect of arbitrarily manipulated gap-graded granular particles on reinforcing foundation soil

  • Xin, Zhen H.;Moon, Jun H.;Kim, Li S.;Kim, Kab B.;Kim, Young U.
    • Geomechanics and Engineering
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    • v.17 no.5
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    • pp.439-444
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    • 2019
  • It is generally known that high strength soil is indicative of well-graded particle size distribution. However, there are some special cases of firm ground despite poor grade distribution, especially a specific gap-graded soil. Based on these discoveries, this study investigated the development of an additive of gap-graded soils designed to increase soil strength. This theoretical concept was used to calculate the mixed ratio required for optimal soil strength of the ground sample. The gap-graded aggregate was added according to Plato's polyhedral theory and subsequently calculated ratio and soil strength characteristics were then compared to characteristics of the original soil sample through various test results. In addition, the underground stress transfer rate was measured according to the test conditions. The test results showed that the ground settlement and stress limit thickness were reduced with the incorporation of gap-graded soil. Further field tests would confirm the reproducibility and reliability of the technology by using gap-graded soil to reinforce soft ground of a new construction site. Gap-graded soil has the potential to reduce the construction cost and time of construction compared to other reinforcing methods.

Preliminary Study for the Development of Optimum Fuel Contact Conductance Model (최적 핵연료 접촉 열전도도 모델 개발을 위한 예비 연구)

  • Yang, Yong-Sik;Shin, Chang-Hwan
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2488-2493
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    • 2007
  • A gap conductance is very important factor which can affect nuclear fuel temperature. Especially, in case of an annular fuel, a gap conductance effect can lead an unexpected heat split phenomena which is caused by a large difference of an inner and outer gap conductance. The gap conductance mechanism is very complicated behavior due to the its strong dependency on microscopic factors such as a contact surface roughness, local contact pressure and local temperature. In this paper, for the decision of test temperature and pressure range, a procedure and calculation results of in-reactor fuel temperature and pressure analysis are summarized which can be applied to test equipment design and determination of test matrix. Based upon analysis results, it is concluded that the minimum and maximum test temperature are $300^{\circ}C$ and $530^{\circ}C$ respectively, and the maximum pellet/cladding interfacial contact pressure should be observed up to 45MPa.

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A Type Test of 154 kV Transmission Line Arrester for improvement of lightning performance (내뢰성 향상을 위한 154 kV 송전선용 피뢰기의 성능 시험)

  • Kwak, J.S.;Kang, Y.W.;Woo, J.W.;Shim, E.B.;Kim, Y.S.
    • Proceedings of the KIEE Conference
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    • 2003.11a
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    • pp.454-456
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    • 2003
  • This paper describes a type test results of 154 kV transmission line arrester with external gap. The test was carried on surge arrester unit and line arrester with external gap, respectively. Withstand voltage test demonstrate the voltage withstand capability of the line arrester with external series gap under the dry and wet conditions. In insulation coordination test external series gap shall be discharged every time when lightning impulse voltage with the steepness of more than 1500 $kV/{\mu}s$ are applied under the wet condition.

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Development of an Aircraft Hydraulic Brake Assembly with a Self-gap-adjuster (자동 간극 조절기를 갖는 항공기용 유압식 브레이크 조립체 개발)

  • Yi, Miseon;Song, Won-Jong;Kwon, Jun-Yong
    • Journal of the Korea Institute of Military Science and Technology
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    • v.23 no.5
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    • pp.444-451
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    • 2020
  • This study was conducted to develop the hydraulic brake assembly for MUAV(Medium-altitude Unmanned Aerial Vehicle). The brake assembly has the self-gap adjuster which performs to maintain a constant gap between the piston and the disk, even if the friction pad wore down. The function of adjuster helps to keep the brake-reaction speed constant and prevent the unnecessary abrasion of the wear pad during the life of the brake assembly. The development of the aircraft hydraulic brake assembly with the self-gap-adjuster in this paper is the first ever in South Korea. The concept of the mechanism was defined and the formula which is necessary to calculate the friction force was set up in the paper. The tester was invented for the functional test and the proper operation of the self-gap-adjuster was confirmed through the test. Dynamo tests and flight tests were also carried out to verify the braking performance of the brake assembly.

Correlation Development on Critical Power in a Spherical Narrow Gap (구형 간극에서의 임계 출력에 대한 상관식 개발)

  • Park, Rae-Joon;Ha, Kwang-Soon;Kim, Sang-Baik;Kim, Hee-Dong;Jeong, Ji-Hwan
    • Proceedings of the KSME Conference
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    • 2001.06e
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    • pp.235-240
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    • 2001
  • The CHFG (Critical Heat Flux in Gap) test results have been evaluated to quantify the critical power in hemispherical narrow gaps and a new correlation has been developed. The CHFG test results have shown that increases in the gap thickness and pressure lead to an increase in critical power. The pressure effect on the critical power was found to be much milder than predictions by CHF correlations of other researches. From the CHFG test results, a new correlation on critical power in the hemispherical gap has been developed using the non-dimensional parameters as follows: $$\frac{qCHF}{{\rho}g^hfg}{\cdot}4\sqrt{\frac{{\rho}_g^2}{g{\sigma}{\Delta}{\rho}}=\frac{0.1042}{1+0.1375({\rho}g/{\rho}l)^{0.21}(D/s)}$$ The developed correlation has been expanded to apply the spherical geometry using the Siemens/KWU's correlation.

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Series-Gap Characteristics of Transmission Line Arrester with Switching and Lightning Impulse Flashover Test (개폐서지 및 뇌충격 섬락시험에 따른 송전 피뢰기의 직렬공극 특성)

  • Cho, Han-Goo;Yoo, Dae-Hoon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.11a
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    • pp.484-485
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    • 2007
  • This paper describes the series-gap characteristics of transmission line arrester with switching and lightning impulse flashover test. The transmission line arrester exhibited external gap because it is must not flashover with switching impulse on the other hand it is must flashover with lightning impulse. In accordance, minimum and maximum length of series-gap was determinated with these tests. As gap length is increased flashover voltage was increased in the range of 315.4 kV~496.3 kV and negative polarity exhibited a high voltage. As a result, It was thought tat the series-gap length of transmission line arrester exhibited in the range of 580 mm~1100 mm.

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Development of the Spark-gap Switch with Dual Trigger System (쌍방향 시동방식의 고속투입스위치 개발)

  • Kim, Maeng-Hyeon;Seo, Yun-Taek;Park, Seung-Jae;Park, Byeong-Rak;Go, Ui-Seok
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.49 no.7
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    • pp.359-364
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    • 2000
  • This paper is introducing a newly developed spark-gap switch with dual trigger system, into which the current from the voltage source is injected along with the test sequence during the synthetic testing of high voltage circuit-breaker. The currently-used spark gap switch is narrow in operating range due to the use of the method of triggering energy being injected by single way. As a result, the frequent happening of misoperation has greatly reduced the test quality and test efficiency and has required the cost of maintenance excessively. In this study, accordingly, in order to basically remove these problems, another triggering system is installed to the opposite direction on the existing triggering system; attaching the same time and the same rising time of pulse wave as on the existing system, so that at a comparatively trigger gap distance from the main electrode(the gap can be operated at 60% of self-break voltage, while at 80% in the current system), the main electrode has been enabled to be closed by the development of spark gap switch with dual trigger system.

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Study on Structural Strength Analysis of Automotive Seat Frame (자동차 시트 프레임의 구조 강도 해석에 관한 연구)

  • Kim, Key-Sun;Kim, Sung-Soo;Kim, Sei-Hwan;Cho, Jae-Ung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.1
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    • pp.39-44
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    • 2013
  • Seat is the part relevant to comfortableness and safety among automotive parts directly. It also should have sufficient stiffness and strength to satisfy these conditions and ensure the safety of passenger. Automotive seat is modelled with 3D and is simulated with structural analyses about three kinds of experiments by before and after gap, side gap, before and after moment strength. As analysis result, deformation angles of $0.038^{\circ}$ and $0.04^{\circ}$ are respectively shown at before and after gap test, side gap test. Through before and after the moment strength test, maximum total deformations of 0.18946mm and 3.2482mm are respectively shown at front and rear loads. By the study result of no excessive deformation and no fracture at automotive seat frame, the sufficient rigidity and strength to guarantee the safety of passenger can be verified.