• Title/Summary/Keyword: Peak pressure

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Changes in Retrogradation Degree of Nonwaxy Rice Cooked at Different Pressure and Stored in Electric Rice Cooker (압력 취반 백미의 전기밥솥 보온중 노화도의 변화)

  • Park, Seok-Kyu;Ko, Yong-Duck;Choi, Ok-Ja;Shon, Mi-Yae;Seo, Kwon-Il
    • Korean Journal of Food Science and Technology
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    • v.29 no.4
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    • pp.705-709
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    • 1997
  • Changes in retrogradation degree of nonwaxy milled rice cooked at different pressure and stored in electric rice cooker at $74^{\circ}C$ were investigated. The moisture contents of nonwaxy milled rice cooked at $1.0{\sim}1.9\;atm\;and\;1.2{\sim}1.5$ water/rice ratio were $59.9{\sim}64.3%$. When nonwaxy milled rice was cooked at high pressure, X-ray diffraction patterns of cooked rice exhibited the V-type having nearly no crystallinity. Retrogradation peak of cooked rice from DSC thermogram was observed in the temperature range of $41.9{\sim}62.4^{\circ}C$ and was not appeared in cooked rice above 1.5 atm. During storage at cooker for 24 hr, retrogradation enthalpy of cooked rice was increased and retrogradation peak was not appeared above 1.7 atm. In cooking and storage of cooked rice, retrogradation degree measured by ${\alpha}-amylase-iodine$ method in high pressure gelatinized samples was lower than that in low pressure gelatinized ones.

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Comparison of plantar pressure and COP parameters in three types of arch support insole during stair descent in elderly with flatfoot (편평족 노인의 계단 하강 보행 시 아치 지지형 인솔 종류에 따른 족저압력 및 균형성 평가)

  • Han, Ki-Hoon;Bae, Kang-Ho;Jung, Ha-gon;Ha, Min-Sung;Choi, Do-Yeol;Lee, Joong-Sook;Yang, Jeong-Ok
    • Journal of the Korean Applied Science and Technology
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    • v.35 no.3
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    • pp.948-955
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    • 2018
  • The purpose of this study was to compare plantar pressure and COP parameters in three types of arch support insole during stair descent in elderly with flatfoot. A total of 14 women elderly were recruited for this study. Pedar-X was used to obtain plantar pressure(peak pressure, mean pressure, and contact area) and COP(distance, displacement, excursion) parameters. One-way ANOVAs were used to compare peak pressure, mean pressure, and contact area, distance of COP, displacement of COP, and excursion of COP. Among the plantar pressure parameters, significant(p<0.05) differences were observed in M3 for the peak pressure, M2, M3, and M4 for the mean pressure, and M2, M3, and M6 for the contact area. Among the COP parameters, distances of COP both in the mediolateral and anteroposterior axes revealed significant(p<0.05) differences. The larger peak pressure values of type A and B insoles were observed as compared to normal insole. The larger peak pressure and shorter COP distance values of type A and B insoles were observed as compared to normal insole.

Characteristics of Negative Peak Wind Pressure acting on Tall Buildings with Step on Wall Surface

  • Yoshida, Akihito;Masuyama, Yuka;Katsumura, Akira
    • International Journal of High-Rise Buildings
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    • v.8 no.4
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    • pp.283-290
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    • 2019
  • Corner cut, corner chamfered or a building shape change are adopted in the design of tall buildings to achieve aerodynamic superiority as well as response reduction. Kikuchi et.al pointed out that large negative peak external pressures can appear near the inside corner of set-back low rise buildings. It is therefore necessary to pay attention to facade design around steps in building surfaces. Peak wind pressures for corner cut or corner chamfered configurations are given in the AIJ code. However, they cannot be applied where there are many variations of vertical and horizontal steps. There has been no previous systematic research on peak wind pressures around steps in building surfaces. In this study, detailed phenomenon of peak wind pressures around steps in buildings are investigated focusing on vertical and horizontal distances from the building's corner.

Stress Index Development for Piping with Trunnion Attachment Under Pressure and Moment Loadings

  • Lee, Dae-hee;Kim, Jong-Min;Park, Sung-ho
    • Nuclear Engineering and Technology
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    • v.29 no.4
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    • pp.310-319
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    • 1997
  • A finite element analysis of a trunnion pipe anchor is presented. The structure is analyzed for the case of internal pressure and moment loadings. The stress results are categorized into the average (membrane) stress, the linearly varying (bending) stress and the peak stress through the thickness. The resulting stresses are interpreted per Section III of the ASME Boiler and Pressure Vessel Code from which the Primary(B$_1$), Secondary(C$_1$) and Peak(K$_1$) stress indices for pressure, the Primary (B$_2$), Secondary(C$_2$) and Peak(K$_2$) stress indices for moment are developed. Based on the comparison between stress value by stress indices derived in this paper and stress value represented by the ASME Code Case N-391-1, the empirical equations for stress indices are effectively used in the piping stress analysis. Therefore, the use of empirical equations can simplify the procedure of evaluating the local stress in the piping design stage.

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Simulation Study on Dynamic Analysis of Spring Type Needle Valve to Absorb Surge Pressure in Pneumatic Cushion Cylinder (공압 쿠션 실린더의 충격압 흡수를 위한 스프링형 니들밸브의 동특성에 관한 연구)

  • Lee J.G.;Xiaofei Qin;Lee J.;Lee J.C.;Shin H.M.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.2 no.1
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    • pp.15-22
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    • 2005
  • The purpose of this study is to find the effective dynamic characteristics of an improved pneumatic cushion cylinder with a spring type needle valve. The dynamic model represented the peak pressure control method when the pneumatic cushion cylinder is moving forward or backward in the horizontal direction. It was found from the simulation results that the peak pressure in the cushion chamber is affected by the spring, which helps to understand the performance of the pneumatic cushion cylinder and to improve or design a better cushion needle valve component. From the simulation results, the stability of pneumatic cushion cylinder with a spring type needle valve was superior and its cushion capability was also better than that without the spring.

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Numerical Analysis of Hypersonic Shock-Shock Interaction using AUSMPW+ Scheme and Gas Reaction Models (AUSMPW+ 수치기법과 반응기체 모델을 이용한 극초음속 충격파-충격파 상호작용 수치해석)

  • Lee Joon-Ho;Kim Chongam;Rho Oh-Hyun
    • 한국전산유체공학회:학술대회논문집
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    • 1999.05a
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    • pp.29-34
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    • 1999
  • A two-dimensional Navier-Stokes code based on AUSMPW+ scheme has been developed to simulate the hypersonic flowfield of hypersonic shock-shock interaction. AUSMPW+ scheme is a new hybrid flux splitting scheme, which is improved by introducing pressure-based weight functions to eliminate the typical drawbacks of AUSM-type schemes, such as non-monotone pressure solutions. To study the real gas effects, three different gas models are taken into account in this paper: perfect gas, equilibrium flow and nonequilibrium flow. It has been investigated how each gas model influences on the peak surface loading, such as wall pressure and wall heat transfer, and unsteady flowfield structure in the region of shock-shock interaction. With the results, the value of peak pressure is not sensitive to the real gas effects nor to the wall catalyticity. However, the value of peak heat transfer rates is affected by the real gas effects and the wall catalyticity. The structure of the flowfield also changes drastically in the presence of real gas effects.

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Effect of Assistant Gas Pressure on Laser Cutting of STS304 (STS304의 레이저 절단에서 보조가스 압력이 미치는 영향)

  • Lee, H.J.;Cho, Y.M.;Yoo, W.J.;Kim, J.D.
    • Journal of the Korean Society for Precision Engineering
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    • v.12 no.3
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    • pp.15-22
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    • 1995
  • This paper presents the effects of assistant gas pressure on laser cutting. To investigate the effects of assistant gas pressure, pressure measuring system was constructed with good handling and precision at low price. The measured results discussed compare with that of laser cutting of STS304. The assistant gas pressure varied with the variation of distance between nozzle and workpiece. The peak pressure existed at some distance and could be known by using the deviced pressure measuring system. The higher assistant gas pressure helps to remove the dross and the exothermic energy out of the material. The quantity of dross beneath the workpiece decreases and the kerf width narrows at measured peak pressure.

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Grid Peak Power Limiting / Compensation Power Circuit for Power Unit under Dynamic Load Profile Conditions (Dynamic Load Profile 조건의 전원 장치에 있어서 계통 Peak Power 제한/보상 전력 회로)

  • Jeong, Hee-Seong;Park, Do-Il;Lee, Yong-Hwi;Lee, Chang-Hyeon;Rho, Chung-Wook
    • The Transactions of the Korean Institute of Power Electronics
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    • v.27 no.5
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    • pp.376-383
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    • 2022
  • The improved performance of computer parts, such as graphic card, CPU, and main board, has led to the need for power supplies with a high power output. The dynamic load profile rapidly changes the usage of power consumption depending on load operations, such as PC power and air conditioner. Under dynamic load profile conditions, power consumption can be classified into maximum, normal, and standby power. Several problems arise in the case of maximum power. Peak power is generated at the system power source in the maximum-power situation. Frequent generation of peak power can cause high-frequency problems and reduce the life of high-pressure parts (especially high-pressure capacitors). For example, when a plurality of PCs are used, system overload occurs due to peak power generation and causes problems, such as power failure and increase in electricity bills due to exceeded contract power. To solve this problem, a system peak power limit/compensation power circuit is proposed for a power supply under dynamic load profile conditions. The proposed circuit detects the system current to determine the power situation of the load. When the system current is higher than the set level, the circuit recognizes that the system current generates peak power and compensates for the load power through a converter using a super capacitor as the power source. Thus, the peak power of loads with a dynamic load profile is limited and compensated for, and problems, such as high-frequency issues, are solved. In addition, the life of high-pressure parts is increased.

Analysis of the Characteristics of Peak External Pressure Coefficient Working on Roof Surface according to the Shape and Layout of Green Houses (비닐하우스의 형태와 배치에 따른 지붕면 피크외압계수 특성분석)

  • You, Ki-Pyo;Paek, Sun-Young;Kim, Young-Moom
    • Journal of Korean Association for Spatial Structures
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    • v.10 no.1
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    • pp.59-66
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    • 2010
  • Among the protected horticulture facilities in Korea, 99.2% are pipe-framed green houses and most of them are structurally vulnerable single-span type green houses. This study examined peak external pressure coefficient for the roof surface of a green house group composed of single-span and a multiple-span green houses. According to the results of the experiment, the distribution of peak external pressure coefficient was around 30% higher in the single-span greenhouse than in the multi-span ones. The external pressure coefficient for the roof surface of the vinyl house group was, in all of the three vinyl houses, was around 20%-30% higher than that for single-span greenhouses.

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