• International Journal of Air-Conditioning and Refrigeration
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• 제10권4호
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• pp.192-200
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• 2002

A modified asymmetric rectangular fin is analysed using the two-dimensional separation of variables method. This modified rectangular fin is made by attaching the wing on the top side of a rectangular fin. Heat loss from each side of this modified rectangular fin is calculated. The relative increasing ratio of heat loss between a modified rectangular fin and a rectangular fin is presented as a function of dimensionless fin volume, wing height and the location of the wing. Especially, to show the remarkable effect of the wing on the heat loss, the relative increasing ratios of heat loss between two different volume increasing methods are listed.

• 약학회지
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• 제21권2호
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• pp.101-109
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• 1977

The effect of humidity on the aging process of hydrous aluminum oxide prepared by the reaction of aluminum chloride and sodium bicarbonate solution at pH 7.8, which was then kept in various atmosphere under relative humidity at 37.deg. was observed by the measurements of acid consuming capacity, X-ray diffraction and IR absorption. The humidity was one of the important factors influencing the aging process of hydrous aluminum oxide during storage. The higer the humidity, the more was accelerated age, crystalize and loss in acid reactivity. Depending on the humidity, the aging product was different, especially, in the case of up to the relative humidity of 72%, it forming bayerite. On the other hand, the hydrous aluminum oxide aged below the relative humidity of 50% was still amorphous even after 120 days storage. When hydrous aluminum oxide was aged under higher humidity, definite IR absorption bands develop as the hydroxys become part of an ordered structure, and it showed their characteristic absorption band around 1630 and 1060 cm$^{-1}$.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1999년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring
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• pp.231-238
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• 1999

The longitudinal dynamic behaviors of the bridge system consisting of multiple simply supported spans under seismic excitations are examined considering pounding effects. The pounding phenomena between adjacent girders which may consequently result in the span collapses are modeled by using the multi-degree-of-freedom system, The inelastic behavior of the RC pier is also considered by adopting the hysteresis loop model and the p-$\delta$ effect. Motions of the foundation and abutment are also considered but the local damage resulting from the girder pounding assumed to be neligible. The developed model is found to give the appropriate information of the dynamic characteristics of the bridge behavior. It is observed that the pounding effect becomes significant as the peak acceleration of the seismic excitation increases. Under minor earthquakes the pounding tends to increase the relative displacements while under strong earthquakes it tends to decrease the relative displacements by restricting the longitudinal girder motions, therefore it is suggested that the pounding effects should be considered in the analysis of the relative displacements of the longitudinally adjacent girder motions.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.377-378
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• 2023

This study examined the effect of curing conditions on the compressive strength of dry mortar for floor. The compressive strength according to the relative humidity during curing was compared, and the influence of expansive additives on compressive strength under water curing was reviewed. As a result, low relative humidity conditions during curing was not effective in improving the compressive strength of dry mortar for floor, and it was judged that the continuous hydration reaction insufficient due to lack of the moisture supply. In order to improve compressive strength, high relative humidity maintenance was found to be an important factor. However, under water curing conditions, the compressive strength has decreased as a result of continuous volume expansion due to the use of the expansive additives.

• Bulletin of the Korean Chemical Society
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• 제25권10호
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• pp.1463-1464
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• 2004

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.116-119
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• 2004

The use of higher strength materials frequently requires the change of design provisions. Following to the previous researches, high strength reinforcing bars have a weak point about the development and splice length. Based on the previous research about high relative rib area, bond strength between reinforcing bars and concrete can be improved by the control of rib height and spacing. But, the code provisions do not include these specific shape of reinforcing bars. So, the purpose of this paper is to determine the effect of relative rib area to the bond strength. This paper describes the experiment and analysis of 5 beam-spliced specimens containing D25 with relative rib areas ranging from 0.073 to 0.17. The test results are also analyzed to make a design formula about the calculation of splice length on the consideration of relative rib area.

• 한국안전학회지
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• 제16권3호
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• pp.99-105
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• 2001

This paper presents results km a series of model tests oil vertically loaded single piles to compare the behaviors of H and pipe piles under the same ground condition. The aims of this paper were to compare the bearing capacity of H-pile md pipe piles under in the same ground condition and to estimate the effect of gravity acceleration and relative soil density. Relative density of soil were made to be 40%, 80% and embedded length of pile on sand was increased by 10, 12, 14, 16 times of the diameter of pile, respectively. As a results of test series, allowable load of H-pile is from 6.4% to 18.2% larger than allowable load of pipe pile in relative density 80% and from 9.1% to 39.4% larger than allowable load of pipe pile in relative density 40%. As a results of numerical analysis, we were predicted behaviour of stress-displacement of pile with model test. In the case of relative density 80% and 40%, bearing capacity of H pile represent from 17.74% to 18.6% larger than allowable load of pipe pile.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.140-150
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• 2004

In this study, the effect of relative position of the blade for the fixed vane has been investigated on blade surface heat transfer. The experiments were conducted in a low speed stationary annular cascade, and heat transfer of blade was examined for six positions within a pitch. Turbine test section has one stage composed of sixteen guide vanes and blades. The chord length of the tested blade is 150 mm and the mean tip clearance of the blade having flat tip is about $2.5\%$ of the blade chord. For the detailed mass transfer measurements on the blade surfaces, a naphthalene sublimation technique was used. The inlet flow Reynolds number is fixed to $1.5{\times}10^5$. Complex heat transfer characteristics are observed on the blade surface due to various flow characteristics, such as separation bubble, relaminarization, transition to turbulence and leakage vortices. The distributions of velocity and turbulence intensity change significantly with the relative position due to the blockage effect of the blade. This causes the variation of heat transfer patterns on the blade surface. The results show that the flow near the leading edge get highly disturbed and deflected toward the either side of the blade when the blade leading edge is positioned close to the trailing edge of the vane. Therefore, separation bubble disappears on the pressure side and overall heat transfer on the relaminarization region is increased. But, due to reduced tip gap flow at the upstream region, the effect of leakage flow on the upstream region of the blade surface is weakened. Thus, the heat transfer characteristics significantly change with the blade positions.

• International Journal of Internet, Broadcasting and Communication
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• 제13권1호
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• pp.47-53
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• 2021

Gait kinematics and kinetics have a similar tendency between men and women, yet it remains unclear how walking while carrying a load affects the gait mechanism. Twenty adults walked with preferred velocity on level ground of 20 m relative to change of a load carriage (no load, 15%, 30% of the body weights) aimed to observe gait mechanism. We measured gait posture using the three-dimensional image analysis and ground reaction force system during stance phase on left foot. In main effect of gender difference, men showed increased displacement of center of gravity (COG) compared to women, and it showed more extended joint angle of hip and knee in sagittal plane. In main effect of a load difference, knee joint showed more flexed postuel relative to increase of load carriage. In main effect of load difference on the kinetic variables, medial-lateral force, anterior-posterior force (1st breaking, 2nd propulsive), vertical force, center of pressure (COP) area, leg stiffness, and whole body stiffness showed more increased values relative to increase of load carriage. Also, men showed more increased COP area compared to women. Interaction showed in the 1st anterior-posterior force, and as a result of one-way variance analysis, it was found that a load main effect had a greater influence on the increase in the magnitude of the braking force than the gender. The data in this study explains that women require little kinematic alteration compared to men, while men in more stiff posture accommodate an added load compared to women during gait. Additionally, it suggests that dynamic stability is maintained by adopting different gait strategies relative to gender and load difference.

• 한국콘텐츠학회논문지
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• 제22권2호
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• pp.270-280
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• 2022

조직 양면성과 장기 성과 간의 관계를 조절하는 변수에 관한 일련의 연구가 있었지만, 전략적 관점에서의 조절변수에 관한 연구는 부족하였다. 본 연구는 기업의 상대적 탐색과 활용이 조직 양면성과 장기 성과와의 관계에 미치는 조절효과를 8,916개의 기업 표본을 바탕으로 분석하였다. 가설 검증 결과, 조직 양면성은 기업의 장기 성과(Tobin's q)에 유의한 정(+)의 영향을 미치는 것으로 나타났다. 기업의 상대적 탐색은 그 관계에 긍정적인 조절효과를 보이고, 기업의 상대적 활용은 부정적인 조절효과를 보이는 것으로 나타났다. 본 연구는 조직 양면성 연구와 전략 연구를 통합했다는 점에서 의미를 가진다. 조직 양면성이 장기 성과의 미치는 긍정적 영향은 기업이 차별화 전략을 사용할 때 더 강화되고 지속되는 반면, 원가우위 전략을 사용할 때는 더 약화되고 지속되기 어렵다.