• Title/Summary/Keyword: Low-pressure

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Effects of Sodium Intakes on Blood Pressure and Blood Parameters in Korean Normal Adult Women (나트륨 섭취수준이 정상 성인 여성의 혈압과 혈액성상에 미치는 영향)

  • 이영근;승정자;최미경;이윤신
    • Journal of Nutrition and Health
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    • v.35 no.7
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    • pp.754-762
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    • 2002
  • This study was performed to investigate the effect of sodium intake on blood pressure and blood parameters. 20 young adult women were fed the diets containing 290.5 mEq (high-Na diet) and 51.3 mEq (low-Na diet) Na for 6 days, respectively. BMI, DBP, and MBP were significantly lower in low-Na diet than those in high-Na diet. 20 subjects were divided into 3 groups according to the salt-sensitivity. In salt-sensitive group, decreases in SBP, DBP, and MBP by low-Na diet were shown. And there were not significant difference in blood pressure of salt-resistant group between high- and low-Na diet. In count-reactive group, MBP in low-Na diet was significantly higher than that in high-Na diet. Hemoglobin, creatinine, uric acid, and haptoglobin levels in serum were significantly higher in low-Na diet than those in high-Na diet. Among groups with different salt-sensitivity, increments of haptoglobin by low-Na diet were shown in salt-sensitive and counter-reactive groups. Actually, low sodium diet affects not only the blood pressure, but other biochemical parameters which in turn affect an individual overall health. Also salt-sensitivity should be considered as an important determinant. Therefore, for the patients who need restricted Na diet, it would be suggested that various biochemical changes and individual salt-sensitivity should be carefully considered along with dietary Na manipulation.

A Study on the Pressure-Swing Distillation of Ethanol-n-Heptane Azeotrope (에탄올-n-헵탄 공비 혼합물의 분리를 위한 압력변환 증류공정 연구)

  • Noh, Sang Gyun
    • Clean Technology
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    • v.21 no.4
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    • pp.217-223
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    • 2015
  • In the present study, modelling and optimization of ethanol-n-heptane separation process were performed using pressure-swing distillation. The pressure-swing distillation process optimization was performed to obtain high purity ethanol and high purity n-heptane into a low-high pressure columns configuration and a high-low pressure columns configuration. The results of pressure-swing distillation process simulation and optimization using high-low pressure column configuration showed a reduced total reboiler heat duty at 5.8% which confirmed a more economical energy consumption.

Prediction of Pulse Pressure and Pulse Interval of Change in Operation Conditions of a Pulse Air Jet Bag Filter (충격기류식 여과집진장치의 운전조건 변화에 따른 적정 탈진주기 및 탈진압력 설정)

  • Lee, Deok-Gi;Lim, Woo-Taik;Cho, Jae-Hwan;Choi, Kum-Chan;Shin, Hyun-Moo;Jang, Seong-Ho;Suh, Jeong-Min
    • Journal of Environmental Science International
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    • v.27 no.6
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    • pp.349-358
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    • 2018
  • In this study, using coke dust from ironwork, the pulse pressure on a pulse air jet bag filter was investigated considering the influence of the pressure loss due to filtration velocity and pressure intervals. The research on the optimal pulse pressure prediction of a pulse air jet type bag filter using coke dust showed the following results. Pressure loss volatility produced by the pulse pressure under low dust concentration(0.5, $1g/m^3$) and low face velocity(1.25 m/min) was less than $10mmH_2O$. This suggests that the pulse pressure has a low impact on the pressure loss. In contrast, pressure loss volatility under high dust concentration($3g/m^3$) and high face velocity(1.75 m/min) was $25mmH_2O$. Therefore, pulse pressure with high dust concentration and high face velocity has a strong influence on the pressure loss volatility, compared to the condition of low dust concentration and low face velocity. The optimal pulse pressure of inlet dust concentration($0.5g/m^3$) was $6kg/cm^2$ under the same face velocity(1.75 m/min). As concentration increased from 1 to $2g/m^3$, the pulse pressure gradually reached $5kg/cm^2$ thus indicating that the pulse pressure($5kg/cm^2$) is pertinent at a high concentration($3g/m^3$). The pulse intervals: 20, 25 and 30 sec, which are relatively longer than 10 and 15 sec, corresponded to high pressure loss volatility produced by the pulse pressure. Furthermore, low pressure loss volatility was noted at $5kg/cm^2$ of the overall pulse pressure.

Distribution of the Garment Pressure by Postures (자세 변화에 따른 의복압 분포 현황)

  • Kim, Yang-Weon;Baek, Yoon-Jeong
    • Journal of the Korean Society of Clothing and Textiles
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    • v.33 no.5
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    • pp.775-781
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    • 2009
  • This study was to investigate the distribution of the garment pressure in daily wearing and in ordinary posture. Ninety-nine college women students majoring the fashion were participated for this study. IBP questionnaire, garment pressure, personal preferring pressure sensations(questionnaire), and subjective garment pressure sensations were measured. There were no significant differences between the data of 2003 and those of 2005. Participants preferred T-shirts and jeans and also preferred slightly fitted style to the loose style. They were classified with the high garment pressure group and the low garment pressure group. Garment pressure from lower garments were usually higher in the high garment pressure group than in the low garment pressure group. There was no significant differences in the upper garments weights between two groups. The lower garments weight of the high garment pressure group showed $533.3{\pm}182.11g/m^2$ and that of the low garment pressure group was $453.4{\pm}181.6g/m^2$. There was a significant difference in the lower garments weight between two groups(p<.01). In a standing posture, there were no significant differences among the distribution of garment pressure. There was a significant garment pressure differences between sitting on a chair and sitting on the floor(p<.001). Participants included in the low garment pressure group felt a higher garment pressure than participants included in the high garment pressure group.

Unsteady Analysis of Acoustic-Pressure Responses of $N_{2}$ Diluted $H_{2}$ and Air Diffusion Flames (희석된 수소/공기 확산화염의 비정상 음향파 응답특성 해석)

  • Sohn, Chae-Hoon
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.320-325
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    • 2003
  • Acoustic-Pressure Response of diluted hydrogen-air diffusion flames is investigated numerically by adopting a fully unsteady analysis of flame structures. In the low-pressure regime, the amplification index remains low and constant at low frequencies. As acoustic frequency increases, finite-rate chemistry is enhanced through a nonlinear accumulation of heat release rate, leading to a high amplification index. Finally, the flame responses decrease at high frequency due to the response lag of the transport zone. For a medium-pressure operation and low-frequency excitation, the amplification index is low and constant. It then decreases at moderate frequencies. As frequency increases further, the amplification index increases appreciably due to an intense accumulation effect.

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Low Level Control of Metal Belt CVT Considering Shift Dynamics and Ratio Valve On-Off Characteristics

  • Kim, Tal-Chol;Kim, Hyun-Soo
    • Journal of Mechanical Science and Technology
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    • v.14 no.6
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    • pp.645-654
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    • 2000
  • In this paper, low level control algorithms of a metal belt CVT are suggested. A feedforward PID control algorithm is adopted for line pressure based on a steady state relationship between the input duty and the line pressure. Experimental results show that feedforward PID control of the line pressure guarantees a fast response while reducing the pressure undershoot which may result in belt slip. For ratio control, a fuzzy logic is suggested by considering the CVT shift dynamics and on-off characteristics of the ratio control valve. It is found from experimental results that a desired speed ratio can be achieved at steady state in spite of the fluctuating primary pressure. It is expected that the low level control algorithms for the line pressure and speed ratio suggested in this study can be implemented in a prototype CVT.

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The Enhacned Atomization of Single Hole Nozzle by Cavitation at The Low Pressure Injection (저압 분사시 캐비테이션에 의한 단공 노즐의 미립화 향상)

  • Son, Jong-Won;Cha, Keun-Jong;Kim, Duck-Jool
    • Proceedings of the KSME Conference
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    • 2001.11b
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    • pp.952-957
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    • 2001
  • The objectives of this investigation were to obtain an excellent spray by cavitation under the low injection pressure. When cavitation occurs in the nozzle hole, the atomization of the liquid jet enhanced considerably. In this experiments, a acrylic nozzle made the gap and installed the bypass in the nozzle hole was used to enhance the atomization of the liquid jet at the low injection pressure. The liquid flow in the nozzle hole was photographed by a transmitted light using a micro flash. The spray angle was measured macroscope images of PMAS and the Sauter mean diameter was measured PDA system. To measure the pressure of the nozzle hole, pressure transducer was used. The results of this study indicated that enhanced atomization of the liquid jet at the low injection pressure was obtained by making the gap and installing the bypass at the single hole nozzle.

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Wind load combinations and extreme pressure distributions on low-rise buildings

  • Tamura, Yukio;Kikuchi, Hirotoshi;Hibi, Kazuki
    • Wind and Structures
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    • v.3 no.4
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    • pp.279-289
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    • 2000
  • The main purpose of this paper is to demonstrate the necessity of considering wind load combinations even for low-rise buildings. It first discusses the overall quasi-static wind load effects and their combinations to be considered in structural design of low-rise buildings. It was found that the maximum torsional moment closely correlates with the maximum along-wind base shear. It was also found that the instantaneous pressure distribution causing the maximum along-wind base shear was quite similar to that causing the maximum torsional moment, and that this asymmetric pressure pattern simultaneously accompanies considerable across-wind and torsional components. Secondly, the actual wind pressure distributions causing maximum quasi-static internal forces in the structural frames are conditionally sampled and their typical pressure patterns are presented.

Fabrication and Wear Property Evaluation for FeCrSi/AC8A Composite by Low-pressure Infiltration (저압함침법에 의한 FeCrSi/AC8A 복합재료의 제조와 마모특성 평가)

  • Song, Tae-Hoon;Lee, Hyun-Jun;Choi, Yong-Bum;Kim, Sung-Jin;Park, Won-Jo
    • Journal of Ocean Engineering and Technology
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    • v.22 no.5
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    • pp.106-111
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    • 2008
  • In this paper, study about property evaluation for the metal matrix composites fabricated by low pressure infiltration process. Aluminum alloy composite which is reinforced by Metal fiber preform was fabricated by low pressure casting process. Infiltration condition was changed the pressure infiltration time of 1 sec, 2 sec and 5 sec under a constant pressure of 0.4 MPa. The molten alloy completely infiltrated the FeCrSi metal perform regardless of the increase in the pressure acceleration time. The the porosity in the FeCrSi/AC8A composite was investigated. The porosity was reduced as the pressure acceleration time as shorter. The FeCrSi/AC8A composite was investigated the wear test for to know the relationship between Porosity and wear resistance. FeCrSi/AC8A composite at pressure acceleration time of 1sec is shown excellent wear resistance.

Performance Evaluation on the Addition of Low-pressure Loop EGR in a Commercial Diesel Engine (상용 디젤엔진의 저압 순환 EGR 추가에 대한 성능 평가)

  • Wang, Tae-Joong;Lee, Jong-Yoon;Shim, Eui-Joon;Kim, Duk-Sang;Lee, Dong-In
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.2
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    • pp.105-110
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    • 2011
  • Through this study, the performance evaluation on the addition of low-pressure loop EGR(Exhaust Gas Recirculation) in a 6.0 L commercial diesel engine was carried out using WAVE modeling and simulation. Since the key technology of advanced diesel engine combustion such as low-temperature combustion is to steadily supply high rates of EGR in a wide operating range, the current study could be effectively contribute to the design and development processes of up-to-date diesel engine systems as real-world reference data. The current simulation results show that the system in which low-pressure loop EGR is added shows almost 2.3 times increase in maximum EGR rate at 1000 rpm as well as almost 1.6 times increase at 2200 and 1600 rpm in comparison with an engine system employing high-pressure loop EGR only. Also, both turbocharger axis speed and charging pressure level did not deteriorate due to the addition of low-pressure loop EGR at 2200 and 1000 rpm, but they were fairly decreased at 1600 rpm.