• Title/Summary/Keyword: Total Pressure Distribution

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Measurement of Unsteady Total Pressure downstream of an 1-Stage Axial Turbine (1단 축류터빈 로터의 후류에서 비정상 전압력 측정에 관한 연구)

  • Kang, Jeong-Seek;Cha, Bong-Jun;Yang, Soo-Seok;Lee, Dae-Sung
    • 유체기계공업학회:학술대회논문집
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    • 2005.12a
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    • pp.318-323
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    • 2005
  • To evaluate the accurate performance of turbomachinery, it is important to measure the unsteady flow phenomena downstream of the rotor blade. This paper presents the development of the fast-response total pressure probe for the measurement of the total pressure field at the exit of rotor and the result of measurement in a 1-stage axial turbine. The fast-response total pressure probe was fabricated by installing a fast-response pressure sensor near the head of a Kiel probe. And it measured the phase-lock averaged total pressure downstream of an 1-stage axial turbine. The developed probe successfully measured the accurate total pressure distribution at rotor exit and made possible to evaluate the loss distribution and the accurate performance of turbomachinery.

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The Comparison of Plantar Pressure Distribution regarding the Extent of Hemineglect in Adult Hemiplegia (성인 편마비 환자의 편측 무시정도에 따른 족저압 비교)

  • Cha, Yong-Jun;Kim, Kyung
    • Journal of the Korean Society of Physical Medicine
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    • v.5 no.1
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    • pp.43-51
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    • 2010
  • Purpose : The purpose of this study was to compare plantar pressure distribution between affected side and unaffected side and to analyze plantar pressure distribution of affected side according to the extent of hemineglect in the adult hemiplegia. Methods : Twenty-five hemiplegia participated in this study. The analysis of plantar pressure distribution was conducted by the F-scan system, and the extent of hemineglect was evaluated with line-bisection test. While the subject walked about 10 meters in their comfortable speed the plantar pressure was evaluated and stored. Results : Total contact area, AP CoP trajectory, contact pressure of mid-foot of the affected side were significantly different from the unaffected side. Total contact area, AP CoP trajectory and contact pressure of mid-foot were smaller than those of unaffected side. In the comparison among the group according to the extent of hemineglect, AP CoP trajectory of subject who has severe hemineglect was significantly different from the patient that has no hemineglect and it was shorter than that of no hemineglect. Conclusion : The plantar pressure distribution was generally different between affected side and unaffected side and the hemineglect affected negatively the patient to move CoP forwardly while walking. Accordingly, it will help the clinician to understand the hemineglect which has an effect on abnormal walking and to intervent the hemiplegia who has a neglection to the affected side.

The Relationships Among Body Fat Distribution, Blood Pressure, Blood Lipids and Exercise in Healthy Men and Women

  • 최미자
    • Journal of the East Asian Society of Dietary Life
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    • v.3 no.2
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    • pp.29-40
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    • 1993
  • A variety of studies show that a centraized rather than a generalized pattern of subcutaneous fat distribution is more directly associated with disorers of carbohydrate and lipid metabolism, as possibly hypertension, This study was an attempt to observe the relationship of body fat distribution, blood lipids, blood pressure and exercise in 85 healthy men and women. Within this group there was a gradation of fat distribution progressing from LBSO and UBSO defined on the basis of WHR. This paper reports the relationship of body fat distribution defined by WHR to plasma glucose, lipids, blood pressure, and exercise in this population. Although the obesity indices(RBW and BMI) were slightly higher in the UBSO group, significant differences existed between UBSO and LBSO groups with respect to WHR blood pressure, and total cholesterol concentration in female. WHR values were substantially different and this was primarily due to greater degrees of differences in waist as opposed to hips circum ference. Although no significant differences existed between UBSO and LBSO groups with respect to age, body weight, and hips circumference, energy intake, total cholesterol, LDL-cholesterol and WHR values were substantially different in male. Positive, significant correlations were found between WHR and both systolic and diastolic blood pressure and between WHR and the total plasma cholesterol concentration and age. When 26 pairs of exercise and nonexercise groups were matched according to sex, age and body weight, blood pressure and blood lipids were significantly lower in the exercise groups than those in the nonexercise groups. In conclusion, these findings suggest that an altered blood lipid profiles will manifast in men and women with upper body obese. Furthermore these findings suggest that exercise and physical activity may be beneficial for controlling blood lipids and blood pressure in healthy adults.

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Evaluation of spatial pressure distribution during ice-structure interaction using pressure indicating film

  • Kim, Hyunwook;Ulan-Kvitberg, Christopher;Daley, Claude
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.6 no.3
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    • pp.578-597
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    • 2014
  • Understanding of 'spatial' pressure distribution is required to determine design loads on local structures, such as plating and framing. However, obtaining a practical 'spatial' pressure distribution is a hard task due to the sensitivity of the data acquisition frequency and resolution. High-resolution Pessure-Idicating Flm (PIF) was applied to obtain pressure distribution and pressure magnitude using stepped crushing method. Different types of PIF were stacked at each test to creating a pressure distribution plot at specific time steps. Two different concepts of plotting 'spatial' pressure-area curve was introduced and evaluated. Diverse unit pixel size was chosen to investigate the effect of the resolution in data analysis. Activated area was not significantly affected by unit pixel size; however, total force was highly sensitive.

Investigation of Pressure Loss in Bent Duct (Bent Duct 내부 유동의 손실 측정)

  • Roh, U-Jin;Im, Ju-Hyun;Song, Seung-Jin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2009.05a
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    • pp.295-298
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    • 2009
  • Bent ducts add loss and decrease efficiency. Many researchers have been conducted the performances of bent ducts, but their shapes of inlet and outlet are same. However, in this investigation, the focus is on a bent duct which is annular at the inlet and circular at the outlet. The bent duct of these complex shapes has not been investigated, but has been used in many fields. The performance of such bent duct is investigated under inlet speed 54 m/s and Re = 238,000. Wall static pressure tappings are located surface of the bent duct to measure the static pressure and a probe is traversed at the inlet and outlet of the bent duct to measure the total pressure. As a result, it presents static pressure distribution on the bent duct surface, streamwise velocity profile at inlet and outlet of the bent duct and total pressure loss profile at outlet. In this investigation, the total pressure loss coefficient is 0.243.

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Leakage Control and Application Using the Pressure Reducing Valve (압력제어밸브를 통한 누수량의 추정과 활용)

  • Kim, Shin-Geol;Kim, Youn-Hwan;Kim, Kyoung-Pil;Koo, Ja-Yong
    • Journal of Korean Society of Water and Wastewater
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    • v.20 no.2
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    • pp.197-206
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    • 2006
  • The leakage in the water distribution system means both the loss of money and water resource. To minimize the leakage, we introduced the pressure control method using the pressure reducing valve and pump schedule. For the pressure control, the total leakage is needed to divide into each node. In this study, EPANET 2.0 was used to simulate the water networks in two selected blocks after the total leakage was distributed with each node by four ways. The leakage was allocated into each node as water measured by meter, water pressure, water faucets and Lpcd and simulated by EPANET 2.0. Regardless of the leakage distribution ways, there was no significant difference between the measured water and the estimated water pressure. Thus, the leakage distribution way using water pressures estimated by simulation could be recommended. The scenarios controlling the pressure reducing valve and pump were made in two blocks(A and B). $86,713m^3/year$ leakage in the A block and $11,442m^3/year$ in the B block could be reduced as controlling the pressure reducing valve and pump schedule. It was shown that the fifty million won a year can be saved in the A block and 6.8 million won in the B block.

Papers : Effects of LEX on the Surface Pressure Distribution over a Delta Wing (논문 : LEX 가 델타형 날개의 표면압력분포에 미치는 영향)

  • Baek, Seung-Uk;Son, Myeong-Hwan
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.30 no.3
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    • pp.1-7
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    • 2002
  • An experimental study was conducted to investigate the effects of leading edge extension(LEX) on the surface prssure distribution over a delta wing in a subsonic wind tunnel. Freestream velocity was 40m/sec and Reynolds number per meter was 1.7x$10^6$ with total pressure of 101Pa and total temperature of 278K. LEX changed the surface pressure distribution on the wing dramatically. Comparing with the results without LEX, the peak of pressure distribution decreased on the front chordwise location but it turned to increase on the rear chordwise location with increase of the angle of attaci. The spanwise gradient of the pressure distribution also increased in the rear chordwise location. Without LEX, the peak of pressure distribution increased and decreased irregularly with increase of the angle of attack at each chordwise location, but LEX made it increased almost linearly with increase of the angle of attack at all of the chordwise locations.

Determination of Optimal Pressure Monitoring Locations of Water Distribution Systems Using Entropy Theory and Genetic Algorithm (엔트로피 이론과 유전자 알고리즘을 결합한 상수관망의 최적 압력 계측위치 결정)

  • Chang, Dong-Eil;Ha, Keum-Ryul;Jun, Hwan-Don;Kang, Ki-Hoon
    • Journal of Korean Society of Water and Wastewater
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    • v.26 no.1
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    • pp.1-12
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    • 2012
  • The purpose of water distribution system is supplying water to users by maintaining appropriate pressure and water quality. For efficient monitoring of the water distribution system, determination of optimal locations for pressure monitoring is essential. In this study, entropy theory was applied to determine the optimal locations for pressure monitoring. The entropy which is defined as the amount of information was calculated from the pressure change due to the variation of demand reflected the abnormal conditions at nodes, and the emitter function (fire hydrant) was used to reproduce actual pressure change pattern in EPANET. The optimal combination of monitoring points for pressure detection was determined by selecting the nodes receiving maximum information from other nodes using genetic algorithm. The Ozger's and a real network were evaluated using the proposed model. From the results, it was found that the entropy theory can provide general guideline to select the locations of pressure sensors installation for optimal design and monitoring of the water distribution systems. During decision-making phase, optimal combination of monitoring points can be selected by comparing total amount of information at each point especially when there are some constraints of installation such as limitation of available budget.

Development and Application of System for Pressure Distribution Measurement (압력분포 측정용 시스템 개발 및 응용)

  • 김용환;박성하
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.6
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    • pp.134-140
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    • 2003
  • The film sensor is used for measuring pressure distribution at planar area, especially at a small space or gap. The present paper deals with the development of film type sensors and system for pressure distribution measuring. The developed system is consist of (1)film sensor with 40/sup */40 array, (2)PCI interface card with maximum sampling rate of 100㎐, and (3)software for data processing and real-time display. The contact pressure test of wiper blade and front glass of vehicle was performed with wiper blade by 40cm. Generally spring force of wiper arm is designed at 0.7∼1kN. Test results of total force was 9.4N and 7.1N in each driver and passenger toward. The paper suggested possibility for base definition in wiper design. A windshield wiper blade experiment revealed that the system successfully measured the contact force distribution during static state, showing the usefulness of the developed system.

A Study on the Distribution of Plantar Pressure in Adult Hemiplegia during Gait with the Use of Cane

  • Cha, Yong-Jun;Kim, Kyoung
    • The Journal of Korean Physical Therapy
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    • v.22 no.3
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    • pp.49-53
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    • 2010
  • Purpose: The purpose of this study was to investigate the plantar pressure distribution between the affected and unaffected side in adult hemiplegia during gait with the use of a quad-cane. Methods: Thirty-four stroke patients from 34 to 83 years of age were enrolled in this study, and in random order, all patients were asked to walk at their most comfortable speed three times along a walkway with the use of quad-cane over a period of three days. Plantar pressure distribution was measured with regard to foot contact pattern and center of pressure (CoP) trajectories during the stance phase, progressing from heel-strike to toe-off. The F-scan system was used to compare the foot pressure of the affected and unaffected sides. Results: A significant reduction in the total contact area, the width of fore foot (FF) and hind foot (HF), and anterior/posterior (AP) CoP trajectory of the affected side was found. However, contact pressure of the hind foot on the affected side during walking increased when compared to that on the unaffected side. Conclusion: We demonstrated that plantar pressure distribution on the affected side of adult hemiplegia patients was generally poorer than that on the unaffected side when these patients walked with cane assistance. However, the use of a quad-cane was shown to increase contact pressure of the hind foot on the affected side because weight can be borne on the affected side during heel-strike with use of the cane.