• Title/Summary/Keyword: Total Pressure

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A Study on the Five - hole Probe Calibration with Non-nulling Method (비영위법에 의한 5공 프로브의 교정에 관한 연구)

  • Jeong, Yang Beom;Sin, Yeong Ho;Park, Ho Dong
    • Journal of Advanced Marine Engineering and Technology
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    • v.20 no.2
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    • pp.116-116
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    • 1996
  • This paper is concerned with a method for calibrating five-hole probes of both angle-tube and prismatic geometries to measure local total and static pressures and the magnitude and direction of the mean velocity vector. Descriptions of the calibration technique, the typical calibration data, and an accompanying discussion of the interpolation procedure are included. The flow properties are determined explicitly from measured probe pressures using calibration data. Flow angles are obtained within the deviation angle of 1.0 degree and dynamic pressures within 0.03 with 95% certainty. The variations in the calibration data due to Reynolds number are also discussed. For the range of Reynolds number employed, no effect was detected on the pitch, yaw and total pressure coefficients. However, the static pressure coefficient showed change to cause minor variations in the magnitude of the calculated velocity vector. To account for these variations, average correction factors need to be incorporated into the static pressure coefficient.

A Study on the Five-hole Probe Calibration with Non-nulling Method (비영위법에 의한 5공 프로브의 교정에 관한 연구)

  • 정양범;신영호;박호동
    • Journal of Advanced Marine Engineering and Technology
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    • v.20 no.2
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    • pp.48-56
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    • 1996
  • This paper is concerned with a method for calibrating five-hole probes of both angle-tube and prismatic geometries to measure local total and static pressures and the magnitude and direction of the mean velocity vector. Descriptions of the calibration technique, the typical calibration data, and an accompanying discussion of the interpolation procedure are included. The flow properties are determined explicitly from measured probe pressures using calibration data. Flow angles are obtained within the deviation angle of 1.0 degree and dynamic pressures within 0.03 with 95% certainty. The variations in the calibration data due to Reynolds number are also discussed. For the range of Reynolds number employed, no effect was detected on the pitch, yaw abd total pressure coefficients. However, the static pressure coefficient showed change to cause minor variations in the magnitude of the calculated velocity vector. To account for these variations, average correction factors need to be incorporated into the static pressure coefficient.

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The effect of Gas Mixture Ratio on Discharge Characteristics of an AC PDP Cell

  • Lee, Hae-June;Lee, D.K.;Choi, J.H.;Cho, Y.S.;Park, H.D.;Lee, H.J.;Park, C.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.171-174
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    • 2005
  • Experimental measurements are reported and compared with the results of a two-dimensional fluid simulation for the investigation of the discharge characteristics regarding the change of the mixture ratio of Ne-Xe-He noble gases. The increase of Xe contents results in the increases of luminance and luminous efficiency while it also results in the increase of the breakdown voltage and the discharge time lag. The addition of He gas increases the brightness and the luminance efficiency. When Xe partial pressure is low, the luminance efficiency increases with the amount of He at the same total pressure. When Xe partial pressure is high, however, the luminance efficiency has a maximum value when the partial pressure of He is about 10% of the total pressure for a standard AC PDP cell with Xe fraction of $10{\sim}30%$.

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The Relationship of Risk Assessment Using Braden Scale and Development of Pressure Sore in Neurologic Intensive Care Unit (Braden scale을 이용한 신경외과 중환자의 욕창 위험 요인 사정과 욕창 발생과의 관계)

  • Lee, Jong-Kyung
    • Korean Journal of Adult Nursing
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    • v.15 no.2
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    • pp.267-277
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    • 2003
  • Purpose: The purpose of this study was to evaluate the applicability of braden scale to assess pressure ulcer risk patients and to identify additional risk factors of pressure sores in an neurologic intensive care unit. Method: The subjects of this study were 66 patients in neurologic intensive care units. Data was prospectively collected from Sep. to Dec., 2002. Data were analyzed by mean, percentage, t-test, chi-square, discriminant analysis using Spss pc+. Result: The results of this study were as follows: 1) There was a significant difference between scoring of braden scale and pressure ulcer development. The subscales that predicted pressure ulcer development using braden scale only were sensory perception, moisture, mobility, friction & shear. By using these subscales, sensitivity was 86.7%, and specificity was 61.1%, and total hit ratio was 72.7%. 2) Additional pressure ulcer risk factors which showed significance for discriminating two group were protein, albumin, gender, level of consciousness, pattern of bowel elimination. By using the combination of these additional risk factors in addition to the braden scale, total hit ratio increased to 84.8%. Conclusion: This data suggest that albumin, protein, gender, level of consciousness, pattern of bowel elimination in addition to the braden scale should be included in the pressure sore assessment tool.

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Analysis of Pressure Drop Characteristics for the Air-Particle Flow in Powder Transport Piping System (입자수송시스템 내 공기-입자 유동장의 압력손실 특성 해석)

  • Lee, Jae-Keun;Ku, Jae-Hyun;Kwon, Soon-Hong
    • The KSFM Journal of Fluid Machinery
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    • v.5 no.1 s.14
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    • pp.20-26
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    • 2002
  • This study reports the analysis of the pressure drop characteristics for the air-particle flow in powder transport piping system. The pressure drop characteristics of air-particle flow in piping system is not well understood due to the complexity of particles motion mechanism. Particles or powders suspended in air flow cause the increase of the pressure drop and affect directly the transportation efficiency. In this study, the pressure drop in powder transport piping system with straight and curved pipes is analyzed for the interactions of air flow and particle motion. The total pressure drop increases with increasing of the pipe length, the mixture ratio, and the friction factor of particles due to the increasing friction loss by air and particles in a coal piping system. For the coal powders of $74{\mu}m$ size and powder-to-air mass mixture ratio of 0.667, the total pressure drop by the consideration of powders and air flow is $30\%$ higher than that of air flow only.

The Experimental Study on the Intraoral Pressure, Closure Duration, and Voice Onset Time(VOT) of Korean Stop Consonants (한국어 파열자음의 인두내압, 폐쇄기 및 Voice Onset Time(VOT)에 관한 실험적 연구)

  • 표화영;심현섭;박헌이;최재영;최성희;안성복;최홍식
    • Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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    • v.10 no.1
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    • pp.50-57
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    • 1999
  • A study to get the data of normal stop consonants production as preliminary study for cleft palate patients was performed. Normal Korean native 21 speakers were pronounced $VCV(V=/a/,C=/P/,/{P^1}/,/P^h/,/t/,/{t^1}/,/{t^h}/,/k/,/{k^1}/,/{k^h}/)$ syllables with natural speech rate and intensity. With intrapharyngeal pressure waveforms by pressure sensor in oropharyngeal cavity, amplitude and time duration of intrapharyngeal pressure were analyzed, and with acoustic waveforms and spectrograms, closure duration and VOT were analyzed. As results, the highest amplitude of intrapharyngeal pressure showed in alveolars and heavily aspirated consonants. Velars and unaspirated consonants were higher than bilabials and slightly aspirated ones each, in intrapharyngeal pressure. Bilabilas, alveolars and velars showed similar rise time of intrapharyngeal pressure build-up, but in decay time and total duration time, bilabials were slightly shorter than alveolars and velars, with no statistic significance. In the aspects of tensity, unaspirated consonants showed the longest rise time, heavily aspirated, the second, and slightly aspirated consonants, the shortest, which were also seen in decay time and total duration time. In closure duration, slightly aspirated consonants had the shortest closure duration, and the heavily aspirated ones, the second, and unaspirated consonants showed the longest. In VOT, heavily aspirated consonants showed the longest, slightly aspirated ones, the second and unaspirated ones showed the shortest.

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The Prediction of Optimal Pulse Pressure Drop by Empirical Static Model in a Pulsejet Bag Filter (경험모델을 이용한 충격기류식 여과집진기의 적정 탈진압력 예측)

  • Suh, Jeong-Min;Park, Jeong-Ho;Lim, Woo-Taik;Kang, Jum-Soon;Cho, Jae-Hwan
    • Journal of Environmental Science International
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    • v.21 no.5
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    • pp.613-622
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    • 2012
  • A pilot-scale pulse-jet bagfilter was designed, built and tested for the effects of four operating conditions (filtration velocity, inlet dust concentration, pulse pressure, and pulse interval time) on the total system pressure drop, using coke dust from a steel mill factory. Two models were used to predict the total pressure drop according to the operating conditions. These model parameters were estimated from the 180 experimental data points. The empirical model (EM) with filtration velocity, areal density, inlet dust concentration, pulse interval time and pulse pressure shows the best correlation coefficient (R=0.971) between experimental data and model predictions. The empirical model was used as it showed higher correlation coefficient (R=0.971) compared to that of the Multivariate linear regression(MLR) (R=0.961). The minimum pulse pressure predicted by empirical model (EM) was 5kg/$cm^2$.

Effectiveness of education regarding cuff pressure after endotracheal intubation (기관내 튜브삽관 후 커프 압력에 대한 교육 효과)

  • Uhm, Dong-Choon;Koh, Bong-Yeun
    • The Korean Journal of Emergency Medical Services
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    • v.21 no.2
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    • pp.7-15
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    • 2017
  • Purpose: This study investigated the effectiveness of education regarding cuff pressure following endotracheal tube intubation using a quasi-experimental design with a pre- and posttest non-equivalent control group. Methods: A total of 78 students from two universities participated in an education intervention on the importance of cuff pressure after endotracheal tube intubation between October and December, 2016. The intervention lasted 40 minutes. Data were collected from each student before the intervention and one week following the intervention. Analyses were conducted using chi-square tests, Fisher's exact tests, and analysis of covariance. Results: A total of 38 students were assigned to the experimental group and 40 to the control group. The educational intervention of cuff pressure following endotracheal tube intubation was associated with prevention of possible complications from excessive cuff pressure (F=121.02, p<.001). Conclusion: Training with a pressure gauge and an intubation manikin is necessary to determine the appropriate cuff pressure in the intubation protocol of the practical examination in the emergency medical technology.

The Effect of Pressure Increase on the Deposition of Tungsten by CVD using SiH4 (SiH$_4$를 이용한 텅스텐의 화학증착시 압력증가가 증착에 미치는 영향)

  • 박재현;이정중;금동화
    • Journal of the Korean institute of surface engineering
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    • v.26 no.1
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    • pp.3-9
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    • 1993
  • Chemical vapor deposited tungsten films were formed in a cold wall reactor at pressures higher (10~120torr) than those conventionally employed (<1torr). SiH4, in addition to H2, was used as the reduction gas. The effects of pressure and reaction temperature on the deposition rate and morphology of the films were ex-amined under the above conditions. No encroachment or silicon consumption was observed in the tungsten de-posited specimens. A high deposition rate of tungsten and a good step coverage of the deposited films were ob-tained at 40~80 torr and at a temperature range of $360~380^{\circ}C$. The surface roughness and the resistivity of the deposited film increased with pressure. The deposition rate of tungsten increased with the total pressure in the reaction chamber when the pressure was below 40 torr, whereas it decreased when the total pressure ex-ceedeed 40 torr. The deposition rate also showed a maximum value at $360^{\circ}C$ regardless of the gas pressure in the chamber. The results suggest that the deposition mechanism varies with pressure and temperature, the surface reac-tion determines the overall reaction rate and (2) at higher pressures(>40 torr) or temperatures(>36$0^{\circ}C$), the rate is controlled by the dtransportation rate of reactive gas molecules. It was shown from XRD analysis that WSi2 and metastable $\beta$-W were also formed in addition to W by reactions between WF6 and SiH4.

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'The effects of Chungsimgangwhawhan (淸心降火丸) on blood pressure and hyperlipidemia' (청심강화환(淸心降火丸)이 고혈압(高血壓) 및 고지혈증(高脂血症)에 미치는 영향(影響))

  • Song, Mi-Deok;Ko, Chang-Nam;Cho, Ki-Ho;Kim, Young-Suk;Bae, Hyung-Sup;Lee, Kyung-Sup
    • The Journal of Korean Medicine
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    • v.16 no.1 s.29
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    • pp.403-418
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    • 1995
  • In order to study the effects of Chungsimgangwhawhan on blood pressure in normal rats and rabbits, and hyperlipidemia induced by 1% cholesterol diet, triton WR-1339, and 75% fructose in mice and rats, the amount of total cholesterol, triglyceride, phospholipid and blood pressure were measured. The results were as follows : 1. After per os medication of Chungsimgangwhawhan, blood pressure in rats were increased but were not significant. 2. Chungsimgangwha-Whan showed strong effects on decreasing blood pressure, depending on the concentration in blood vessels of rabbits. 3. In the model of hyperlipidemia induced by 1% cholesterol diet in mice, Chungsimgangwhawhan showed decreasing effects on total cholesterol level in serum significantly (p<0.05) depending on the concentration, and on triglyceride (p<0.01) and phospholipid level (p<0.001) in serum. 4. In the model of hyperlipidemia induced by triton WR-1339 in rats, Chungsimgangwhawhan showed mild decreasing effects on total cholesterol level in serum, but was not significant. 5. In the model of hyperlipidemia induced by 75% fructose in rats, Chungsimgangwhawhan showed decreasing effects on total cholesterol and triglyceride level in serum significantly(p<0.01) depending on the concentration. According to the above results, Chungsimgangwhawhan showed significant decreasing effects on blood pressure and hyperlipidemia, and it is considered that it is appropriate to apply for hypertension and hyperlipidemia.

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