• 제목/요약/키워드: mean pressure coefficients

검색결과 143건 처리시간 0.032초

노인의 식이섭취 실태와 건강상태에 관한 연구 II -영동지역을 중심으로- (A study on the dietary intake and health of aged person II -Based in elderly person in Young Dong area-)

  • 염초애;장명숙;이현옥
    • 한국식품영양과학회지
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    • 제16권4호
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    • pp.317-322
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    • 1987
  • The Purpose of this study· was to investigate the dietary intake and health for male and female old persons living in Young Dong by mean of questionnaire and interview. The results from the above survey are summerized as follows ; 1. The aged average height, weight, and physical index were 166cm, 60kg, 19.31 in male, 156cm, 50kg, 20.27 in female which were almost the same as the Korean average standard (male; 167. 0cm, 61. 0kg, 21.8, female; 156cm, 53.0kg, 21.8). Among the condition of diseases, neuralgia was 45.3%, hypertension was 12.2%, constipation was 10.4%. 2. Correlation coefficients between systolic blood pressure, diastolic blood pressure and age were significant(P<0.05, P<0.01), and also those between systolic blood pressure, diastolic blood pressure and Body Mass Index were significant(P<0.01, P<0.005). 3. Correlation of food intake frequency of protein group, calcium group, vitamin and mineral group was divided three levels-Good, Fair, Poor. Food intake frequency as the factors(three groups) which might influence the condition of health was partly significant (P<0.05, P<0.1).

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PSP를 이용한 항공기 형상 모형 날개 표면 압력 측정 (Surface pressure measurement on a wing of SWIM by using PSP)

  • 정혜진;권기정
    • 한국항공우주학회지
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    • 제36권4호
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    • pp.337-345
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    • 2008
  • 연구에서는 NACA4412익형으로 이루어진 주날개에 NACA0012플랩이 장착된 아음속 벽면효과 모형(SWIM)의 날개 표면 3차원 압력 분포를 압력감응페인트를 이용하여 시험적으로 연구하였다. 한국항공우주연구원의 아음속 풍동에서 레이놀즈수 3.1x105의 조건에서 시험 모형의 받음각 변화에 따른 날개 윗면 및 아랫면의 압력 분포를 측정하였다. 그 결과 받음각이 증가함에 따라 날개 윗면에서의 최저 압력 지점이 뿌리에서 끝단으로 이동을 하는 것을 관찰하였고, 날개 끝단의 뒷전에서도 끝단 와류를 일으키는 압력이 매우 낮은 지점도 관찰되었다. 그러나 실속각 이후인 받음각 15도의 경우 끝단 뒷전에서는 압력이 낮은 지점이 계속 관찰되었으나 그 이외의 부분은 스팬 방향 압력 분포가 편평하였다. 압력감응페인트와 더불어 압력공을 사용하여 날개의 코드 방향 2차원 압력분포도 측정 하여 비교하였고 두 시험에서 측정된 각 압력계수들의 차이의 평균은 약 0.077임을 확인하였다.

협심증이 의심되는 환자에서 운동부하검사로 유발되는 흉통의 양상과 생리적 변인에 관한 연구 (A study on characteristics and physiological variables of chest pain induced by exercise test in angina suspected patients)

  • 조미경;최명애
    • Journal of Korean Biological Nursing Science
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    • 제2권2호
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    • pp.1-19
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    • 2000
  • The purpose of this study was to identify the characteristics and physiological variables of chest pain induced by exercise test in angina suspected patients. The subjects of this study consisted of 28 inpatients and outpatients aged between 40 and 75 who underwent treadmill test at exercise testing laboratory of S-University from January 2000 to June 2000. Subjects were interviewed with questionnaire regarding sociodemography, the past health history and history related to chest pain before the exercise test. Subjects were interviewed with questionnaire concerning quality, intensity, duration of chest pain induced by walking on the treadmill(Marquette, U.S.A. 1992) according to Bruce protocol following exercise test. Systolic and diastolic blood pressure were measured before, during and after the test, heart rate was determined by ECG. The results of this study were as follows ; 1) Quality of chest pain induced by exercise test were feeling stiffness 19(67.9%), heavy 10(36.0%), exploded 9(32.1%), crushing, suffocating, tight 8(28.6%), stuffy, prickly 7(25.0%), burning 6(21.4%), clasp 5(17.9%), cleaved, tensed, piercing 3(10.7%), perfectly fitting, sore 2(7.1%), tearing, tingling, ticklish, heartburn 1(3.6%). 2) Mean score of VAS(intensity of pain) following exercise test was $5.79{\pm}2.27$ and mean duration of chest pain after the test was $7.83{\pm}5.31$ minutes. 3) Sites of chest-pain induced by exercise test were middle site 11(39.3%), left-chest 10(35.6%), right-chest 6(21.5%). Radiation site of chest-pain was neck(18.0%), right flank site 1(3.6%), left shoulder & arm 2(7.1%) and back 1(3.6%). 4) Symptoms other than chest-pain induced by exercise test were dyspnea 21(75.6%), perspiration 14(50.4%), fatigue 12(43.2%), leg-pain 11(39.6%), dizziness 7(25.2%) anxiety toward chest-pain 3(10.8%), thirst 2(7.1%), and palpation, headache and tingling sensation of hand and leg 1(3.6%). 5) Mean MET(intensity of exercise) during the exercise test was $7.64{\pm}2.57$ and mean RPE(rating of perceived exertion) was $15.89{\pm}2.36$. Mean duration of exercise was $6.79{\pm}2.88$. 6) correlation coefficients between RPE and VAS was 0.500(p=0.003), those between MET and VAS was 0.287(p=0.069) and those between either depression or elevation of ST segment and VAS was 0.236(p=0.114). 7) There was a significant difference in mean systolic pressure between before and after the test as $146.29{\pm}28.18mmHg$ and $177.96{\pm}28.82mmHg$(t=-5.640, p=0.000), a significant difference in mean diastolic blood pressure between before and after the test as $84.85{\pm}15.07mmHg$ and $88.89{\pm}13.72mmHg$(t=-2.082, p=0.047), and there was a significant difference in mean heart-rate between before and after the test as $81.89{\pm}12.22/min$ and $160.68{\pm}21.77/min$(t=-21.255, p=0.000).

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탄화수소계 냉매들과 DME의 수평 평활관내 흐름 응축 열전달 특성 (Flow Condensation Heat Transfer Characteristic of Hydrocarbon Refrigerants and DME in Horizontal Plain Tube)

  • 박기정;이민행;박현신;정동수
    • 설비공학논문집
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    • 제19권7호
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    • pp.545-554
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    • 2007
  • Flow condensation heat transfer coefficients(HTCs) of R22, propylene, propane, DME and isobutane are measured on a horizontal plain tube. The main test section in the experimental flow loop is made of a plain copper tube of 9.52 mm outside diameter and 530 mm length. The refrigerant is cooled by passing cold water through an annulus surrounding the test section. Tests are performed at a fixed refrigerant saturation temperature of $40{\pm}0.2^{\circ}C$ with mass fluxes of 100, 200, $300kg/m^2s$ and heat flux of $7.3\sim7.7kW/m^2$. The data are obtained in the vapor Quality range of $10\sim90%$. Test results show that at same mass flux the flow condensation HTCs of propylene, propane, DME and isobutane are higher than those of R22 by up to 46.8%, 53.3%, 93.5% and 61.6% respectively. Also well-known correlations developed based upon conventional fluorocarbon refrigerants predict the present data within a mean deviation of 30%. Finally, the pressure drop increase as the mass flux and Quality increase and isobutane shows the highest pressure drop due to its lowest vapor pressure among the fluids tested.

Reynolds Number Effects on the Non-Nulling Calibration of a Cone-Type Five-Hole Probe for Turbomachinery Applications

  • Lee, Sang-Woo;Jun, Sang-Bae
    • Journal of Mechanical Science and Technology
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    • 제19권8호
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    • pp.1632-1648
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    • 2005
  • The effects of Reynolds number on the non-nulling calibration of a typical cone-type five-hole probe have been investigated for the representative Reynolds numbers in turbomachinery. The pitch and yaw angles are changed from - 35 degrees to 35 degrees with an angle interval of 5 degrees at six probe Reynolds numbers in range between $6.60{\times}10^3\;and\;3.17{\times}10^4$. The result shows that not only each calibration coefficient itself but also its Reynolds number dependency is affected significantly by the pitch and yaw angles. The Reynolds-number effects on the pitch- and yaw-angle coefficients are noticeable when the absolute values of the pitch and yaw angles are smaller than 20 degrees. The static-pressure coefficient is sensitive to the Reynolds number nearly all over the pitch- and yaw-angle range. The Reynolds-number effect on the total-pressure coefficient is found remarkable when the absolute values of the pitch and yaw angles are larger than 20 degrees. Through a typical non-nulling reduction procedure, actual reduced values of the pitch and yaw angles, static and total pressures, and velocity magnitude at each Reynolds number are obtained by employing the calibration coefficients at the highest Reynolds number ($Re=3.17{\times}10^4$) as input reference calibration data. As a result, it is found that each reduced value has its own unique trend depending on the pitch and yaw angles. Its general tendency is related closely to the variation of the corresponding calibration coefficient with the Reynolds number. Among the reduced values, the reduced total pressure suffers the most considerable deviation from the measured one and its dependency upon the pitch and yaw angles is most noticeable. In this study, the root-mean-square data as well as the upper and lower bounds of the reduced values are reported as a function of the Reynolds number. These data would be very useful in the estimation of the Reynolds-number effects on the non-nulling calibration.

수평미세관내 NH3 비등열전달 특성 (Boiling Heat Transfer of Ammonia inside Horizontal Smooth Small Tube)

  • 최광일;오종택
    • 설비공학논문집
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    • 제25권2호
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    • pp.101-108
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    • 2013
  • This paper is presented an experimental study of flow boiling heat transfer characteristics of ammonia, and is focused on pressure gradient and heat transfer coefficient of the refrigerant flow inside horizontal small tube with inner diameter of 3.0 mm and length of 2000 mm. The direct heating method is applied for supplying heat to the refrigerant, where the test tube is uniformly heated by electric current. The local heat transfer coefficients were obtained over a heat flux range of 20 to $80kW/m^2$, a mass flux range of 50 to $500kg/m^2s$, a saturation temperature range of 0 to $10^{\circ}C$, and quality up to 1.0. The pressure drops increase with increasing mass flux and heat flux, and with decreasing saturation temperature. The heat transfer coefficients increase with increasing mass flux and saturation temperature in middle and high quality region. And the local heat transfer coefficient increase with increasing heat flux in low quality region. The heat transfer coefficient of the experimental result was compared with six existing heat transfer coefficient correlation. A new boiling heat transfer coefficient correlation based on the superposition model for ammonia in small tubes is developed average deviation of -0.17% and mean deviation of 10.85%.

Advances in the design of high-rise structures by the wind tunnel procedure: Conceptual framework

  • Simiu, Emil;Yeo, DongHun
    • Wind and Structures
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    • 제21권5호
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    • pp.489-503
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    • 2015
  • This paper surveys and complements contributions by the National Institute of Standards and Technology to techniques ensuring that the wind tunnel procedure for the design of high-rise structures is based on sound methods and allows unambiguous inter-laboratory comparisons. Developments that enabled substantial advances in these techniques include: Instrumentation for simultaneously measuring pressures at multiple taps; time-domain analysis methods for estimating directional dynamic effects; creation of large simulated extreme directional wind speed data sets; non-parametric methods for estimating mean recurrence intervals (MRIs) of Demand-to-Capacity Indexes (DCIs); and member sizing based on peak DCIs with specified MRIs. To implement these advances changes are needed in the traditional division of tasks between wind and structural engineers. Wind engineers should provide large sets of directional wind speeds, pressure coefficient time series, and estimates of uncertainties in wind speeds and pressure coefficients. Structural engineers should perform the dynamic analyses, estimates of MRIs of wind effects, sensitivity studies, and iterative sizing of structural members. The procedure is transparent, eliminates guesswork inherent in frequency domain methods and due to the lack of pressure measurements, and enables structural engineers to be in full control of the structural design for wind.

유체의 흐름이 있는 엔진 흡기계용 직조관의 음향 임피던스 측정 및 전달손실 예측 (Measurement of acoustic impedance of porous woven hoses in engine intake systems in the presence of mean flow)

  • 이정권;박철민
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2002년도 춘계학술대회논문집
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    • pp.996-1000
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    • 2002
  • A porous tube, comprised of a resin-coated woven fabric has recently been used as an effective component for use in intake systems of internal combustion engines to reduce the intake roaring. For the prediction of the acoustic performance of an engine intake system with a porous woven hose, the acoustic wall impedance of the hose must be known. Because of its peculiar acoustical and structural characteristics, the accurate measurement of the wall impedance ofa porous woven hose is not easy. A new measurement technique is proposed herein, that is valid over the low to mid frequency ranges. The acoustics impedance is inversely estimated from an overdetermined set of measured pressure transmission coefficients for specimens of different lengths and the reflection coefficient of end termination. The method involves only one measurement, and, as a result, it is very simple. The measured TL for samples with arbitrary conditions, arbitrary porous frequency, arbitrary length, and arbitrary mean flow condition, are in reasonably good agreement with values predicted from curve-fitted impedance data.

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Open-jet boundary-layer processes for aerodynamic testing of low-rise buildings

  • Gol-Zaroudi, Hamzeh;Aly, Aly-Mousaad
    • Wind and Structures
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    • 제25권3호
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    • pp.233-259
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    • 2017
  • Investigations on simulated near-surface atmospheric boundary layer (ABL) in an open-jet facility are carried out by conducting experimental tests on small-scale models of low-rise buildings. The objectives of the current study are: (1) to determine the optimal location of test buildings from the exit of the open-jet facility, and (2) to investigate the scale effect on the aerodynamic pressure characteristics. Based on the results, the newly built open-jet facility is well capable of producing mean wind speed and turbulence profiles representing open-terrain conditions. The results show that the proximity of the test model to the open-jet governs the length of the separation bubble as well as the peak roof pressures. However, test models placed at a horizontal distance of 2.5H (H is height of the wind field) from the exit of the open-jet, with a width that is half the width of the wind field and a length of 1H, have consistent mean and peak pressure coefficients when compared with available results from wind tunnel testing. In addition, testing models with as large as 16% blockage ratio is feasible within the open-jet facility. This reveals the importance of open-jet facilities as a robust tool to alleviate the scale restrictions involved in physical investigations of flow pattern around civil engineering structures. The results and findings of this study are useful for putting forward recommendations and guidelines for testing protocols at open-jet facilities, eventually helping the progress of enhanced standard provisions on the design of low-rise buildings for wind.

수압 측정에 기반하는 요류검사의 정확도 검증 (Accuracy Validation of Urinary Flowmetry Technique Based on Pressure Measurement)

  • 최성수;이인광;김군진;강승범;박경순;이태수;차은종;김경아
    • 대한의용생체공학회:의공학회지
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    • 제29권3호
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    • pp.198-204
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    • 2008
  • Uroflowmetry is a non-invasive clinical test useful for screening benign prostatic hyperplasia(BPH) common in the aged men. The current standard way to obtain the urinary flow rate is to continuously acquire the urine weight signal proportional to volume over time. The present study proposed an alternative technique measuring pressure to overcome noise problems present in the standard weight measuring technique. Experiments were performed to simultaneously acquire both weight and pressure changes during urination of 9 normal men. Noise components were separated from volume signals converted from both weight and pressure signals based on the polynomial signal model. Signal-to-noise ratio was defined as the ratio of the energies between signal and noise components of the measured volume changes, which was 8.5 times larger in the pressure measuring technique, implying that cleaner signal could be obtained, more immune to noisy environments. When four important diagnostic parameters were estimated, excellent correlation coefficients higher than 0.99 were resulted with mean relative errors less than 5%. Therefore, the present pressure measurement seemed valid as an alternative technique for uroflowmetry.