• Title/Summary/Keyword: pulse wave velocity

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Study on the frequency of self-excited pulse jet

  • Wang, Jian;Li, Jiangyun;Guan, Kai;Ma, Tianyou
    • International Journal of Fluid Machinery and Systems
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    • v.6 no.4
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    • pp.206-212
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    • 2013
  • Self-excited pulse jet is a specific nozzle with a closed chamber which can change a continuous jet into a pulse one. Energy of the pulse jet can be output not only unevenly but also with multifrequency. With the peak pressure of pulse jet, the hitting power would be 2~2.5 times higher than that of continuous jet. In order to reveal the correlation between the self-excited pulse frequency and nozzle diameter ratio, nozzle spacing and operating pressure, the model of 3D unsteady cavitation model has been used. We found that with the same nozzle structure parameters and the different operating pressure, the self-excited frequency and the width of peak crest are different, but the wave profiles are similar. With FFT, we also found that the less bandwidth of amplitude in low frequency range will lead to the wider wave crest of outlet velocity in its time domain, and the larger force of the strike will be gained. By studying the St of self-excite nozzle, not only the frequency of a certain nozzle can be predicted, but also a nozzle structure with a certain frequency can be designed.

Aerobic Exercise's Influence on Obese Female College Students'Arterial Pulse Wave Velocity, Cardiorespiratory Systems and Body Composition (유산소 운동이 비만 여자대학생의 동맥맥파속도, 호흡순환계 및 신체조성에 미치는 영향)

  • Kim, Seung-Suk
    • Journal of Digital Convergence
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    • v.15 no.7
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    • pp.407-414
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    • 2017
  • In order to identify an Convergence aerobic exercise's influence on obese female college students' Cardiorespiratory systems and arterial pulse wave Velocity, this study targeted female college students in D University in Y-gu, D-City, and selected total 26 ones having body fat percentage over 30% with no special disease in past and at present and no regular physical activity. After finally confirming their participation in this experiment by completely explaining the purpose of and contents of this experiment and getting the subjects' written contents to participate in the experiment, the investigator randomly arranged the subjects into the exercise group(N=13) and the control group(N=13) and conducted a 12-week aerobic exercise program to the exercise group this study got the following conclusion. First, concerning the body composition's change, the exercise group showed significant reduction in the weight, the body fat percentage, and the abdominal fat percentage. Second, for the respiratory & cardiovascular systems'change, the exercise group showed significant increase in the maximal oxygen uptake, the maximal heart rate, and the maximal breathing capacity. Third, for the arterial pulse wave Velocity's change, the exercise group showed significant reduction in the upper body(right and left hands) and lower body (right and left feet).

A Study on the Statistical Distribution of Ultrasonic Velocities for the Condition Evaluation of Concrete Wide Beam (콘크리트 넓은 보의 상태평가를 위한 초음파 속도의 통계학적 분포에 대한 연구)

  • Yoon, Young-Geun;Lee, In-Bok;Sa, Min-Hyung;Oh, Tae Keun
    • Journal of the Korean Society of Safety
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    • v.32 no.2
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    • pp.98-104
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    • 2017
  • The ultrasonic pulse velocities of pressure, shear, and Rayleigh waves ( P-, S-, and R- waves) have been used for the condition evaluation of various concrete structures, but the statistical distribution according to the wave type has not been studied clearly in view of data reliability and validity. Therefore, this study analyzed the statistical distribution of P-, S-, R-wave velocities in concrete wide beams of $800{\times}3100mm$ (width ${\times}$ length) with a thickness of 300 mm. In addition, we investigated an experimental consistency by the Kolmogorov-Smirnov goodness-of-fit test. The experimental data showed that the R-, S- and P- wave velocities in order have better statistical stability and reliability for in situ evaluation because R- and S-waves are less sensitive to confinement and boundary conditions. Also, good correlations between wave velocities and strength and modulus of elasticity were found, which indicate them as appropriate techniques for estimating the mechanical properties.

Characteristic Study of the Pulse Position on CHON, KWAN and CHUCK Using the Ultrasonic Waves (초음파 분석을 이용한 촌관척 위치별 혈관의 특성연구)

  • Lee, Yu-Jung;Lee, Jeon;Lee, Hae-Jung;Ryu, Hyun-Hee;Choi, Eun-Ji;Kim, Jong-Yeol
    • Korean Journal of Oriental Medicine
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    • v.13 no.3
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    • pp.111-117
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    • 2007
  • The study aims to measure and analyze the thickness and depth of blood vessel on the pulse diagnosis locations and the blood velocity through the use of ultrasonic waves (LOGIQ5PRO, GE Medical, U.S.) in order to understand the structural difference of pulse diagnosis locations. The subjects included 44 healthy men and women(22.28${\pm}$2.62 age) considered normal in terms of Body Mass Index(BMI). The thickness and depth of the blood vessel and the blood velocity were measured three times on CHON, KWAN and CHUCK to obtain the average value. Results showed there is a statistically significant difference among the variables measured on CHON, KWAN and CHUCK. A difference according to gender was also observed. This explains why an oriental medical doctor can tell the difference in pulses depending on the location of CHON, KWAN and CHUCK. In addition, the difference in pressure between CHON and KWAN was higher than that in pressure between KWAN and CHUCK. The findings explain why oriental medical doctors take pulses by dividing CHON, KWAN and CHUCK in the short length of the three fingers. It can be used to develop a pulse diagnosis device enabling accurate measurement according to the characteristics of blood vessel structure based on where the pulse is taken. Furthermore, the results can be used as basic data for the development of a pulse diagnosis simulator.

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A Wrist Watch-type Cardiovascular Monitoring System using Concurrent ECG and APW Measurement

  • Lee, Kwonjoon;Song, Kiseok;Roh, Taehwan;Yoo, Hoi-jun
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.16 no.5
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    • pp.702-712
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    • 2016
  • A wrist watch type wearable cardiovascular monitoring device is proposed for continuous and convenient monitoring of the patient's cardiovascular system. For comprehensive monitoring of the patient's cardiovascular system, the concurrent electrocardiogram (ECG) and arterial pulse wave (APW) sensor front-end are fabricated in $0.18{\mu}m$ CMOS technology. The ECG sensor frontend achieves 84.6-dB CMRR and $2.3-{\mu}Vrms$-input referred noise with $30-{\mu}W$ power consumption. The APW sensor front-end achieves $3.2-V/{\Omega}$ sensitivity with accurate bio-impedance measurement lesser than 1% error, consuming only $984-{\mu}W$. The ECG and APW sensor front-end is combined with power management unit, micro controller unit (MCU), display and Bluetooth transceiver so that concurrently measured ECG and APW can be transmitted into smartphone, showing patient's cardiovascular state in real time. In order to verify operation of the cardiovascular monitoring system, cardiovascular indicator is extracted from the healthy volunteer. As a result, 5.74 m/second-pulse wave velocity (PWV), 79.1 beats/minute-heart rate (HR) and positive slope of b-d peak-accelerated arterial pulse wave (AAPW) are achieved, showing the volunteer's healthy cardiovascular state.

Underwater object radial velocity estimation method using two different band hyperbolic frequency modulation pulses with opposite sweep directions and its performance analysis (두 대역 상반된 스윕방향 hyperbolic frequency modulation 펄스로 수중물체 시선속도추정 기법 및 성능분석)

  • Chomgun Cho;Euicheol Jeong
    • The Journal of the Acoustical Society of Korea
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    • v.42 no.1
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    • pp.25-31
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    • 2023
  • In order to estimate the radial speed of an underwater object so-called target with active sonar, Continuous Wave (CW) pulse is generally used, but if a target is slow and at near distance, it is not easy to estimate the radial velocity of the target due to acoustic reverberation in the ocean. In 2017, Wang et al. utilized broadband signal of two Hyperbolic Frequency Modulation (HFM) pulses, which is known as a doppler-invariant pulse, with equal frequency band and in opposite sweep directions to overcome this problem and successfully estimate the radial speed of slow-moving nearby target. They demonstrated the estimation of the radial velocity with computer simulation using the parameters of two HFM starting time differences and receiving times. However, for it uses two HFM pulses with equal frequency, cross-correlation between the two pulses negatively affect the detection performance. To mitigate this cross-correlation effect, we suggest using two different band HFM with the opposite sweep directions. In this paper, a method of radial velocity estimation is derived and simulated using two HFM pulses with the pulse length of 1 second and bandwidth of 400 Hz. Applying the suggested method, the radial velocity was estimated with approximately 6 % of relative error in the simulation.

Reproducibility of Regional Pulse Wave Velocity in Healthy Subjects

  • Im Jae-Joong;Lee, Nak-Bum;Rhee Moo-Yong;Na Sang-Hun;Kim, Young-Kwon;Lee, Myoung-Mook;Cockcroft John R.
    • International Journal of Vascular Biomedical Engineering
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    • v.4 no.2
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    • pp.19-24
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    • 2006
  • Background: Pulse wave velocity (PWV), which is inversely related to the distensibility of an arterial wall, offers a simple and potentially useful approach for an evaluation of cardiovascular diseases. In spite of the clinical importance and widespread use of PWV, there exist no standard either for pulse sensors or for system requirements for accurate pulse wave measurement. Objective of this study was to assess the reproducibility of PWV values using a newly developed PWV measurement system in healthy subjects prior to a large-scale clinical study. Methods: System used for the study was the PP-1000 (Hanbyul Meditech Co., Korea), which provides regional PWV values based on the measurements of electrocardiography (ECG), phonocardiography (PCG), and pulse waves from four different sites of arteries (carotid, femoral, radial, and dorsalis pedis) simultaneously. Seventeen healthy male subjects with a mean age of 33 years (ranges 22 to 52 years) without any cardiovascular disease were participated for the experiment. Two observers (observer A and B) performed two consecutive measurements from the same subject in a random order. For an evaluation of system reproducibility, two analyses (within-observer and between-observer) were performed, and expressed in terms of mean difference ${\pm}2SD$, as described by Bland and Altman plots. Results: Mean and SD of PWVs for aorta, arm, and leg were $7.07{\pm}1.48m/sec,\;8.43{\pm}1.14m/sec,\;and\;8.09{\pm}0.98m/sec$ measured from observer A and $6.76{\pm}1.00m/sec,\;7.97{\pm}0.80m/sec,\;and\;\7.97{\pm}0.72m/sec$ from observer B, respectively. Between-observer differences ($mean{\pm}2SD$) for aorta, arm, and leg were $0.14{\pm\}0.62m/sec,\;0.18{\pm\}0.84m/sec,\;and\;0.07{\pm}0.86m/sec$, and the correlation coefficients were high especially 0.93 for aortic PWV. Within-observer differences ($mean{\pm}2SD$) for aorta, arm, and leg were $0.01{\pm}0.26m/sec,\;0.02{\pm}0.26m/sec,\;and\;0.08{\pm}0.32m/sec$ from observer A and $0.01{\pm}0.24m/sec,\;0.04{\pm}0.28m/sec,\;and\;0.01{\pm}0.20m/sec$ from observer B, respectively. All the measurements showed significantly high correlation coefficients ranges from 0.94 to 0.99. Conclusion: PWV measurement system used for the study offers comfortable and simple operation and provides accurate analysis results with high reproducibility. Since the reproducibility of the measurement is critical for the diagnosis in clinical use, it is necessary to provide an accurate algorithm for the detection of additional features such as flow wave, reflection wave, and dicrotic notch from a pulse waveform. This study will be extended for the comparison of PWV values from patients with various vascular risks for clinical application. Data acquired from the study could be used for the determination of the appropriate sample size for further studies relating various types of arteriosclerosis-related vascular disease.

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On Study of Pulse Wave Signal According to Postural Change Using Finger Plethysmography (손가락 끝 용적맥파를 이용한 자세변화에 따른 맥파 신호에 관한 연구)

  • Choi, B.C.;Kim, C.H.;Jung, D.K.;Suh, D.J.
    • Proceedings of the KOSOMBE Conference
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    • v.1998 no.11
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    • pp.125-126
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    • 1998
  • Pulse conduction velocity is determined by areterial compliance, which is changed by lateral pressure of arterial wall. Hydrostatic pressure of the limb vessel is changed by body position, especially in elevated arm. The arterial pulse in the finger causes the blood volume to change, changing the optical density of the blood. Photoplethysmograph of index finger was obtained by LED and phototransistor. Pulse transmission time(PTT) was measured by the interval between the peak of ECG R wave and the peak of the finger plethysmogram. PTT was increased by upward position of arm, and decreased by downward position of the arm compared to horizontal position. This result suggests that relationship between finger plethysmography and postural change could be applied to evaluate clinical cardiovascular status.

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Association of Uric Acid Levels with Arterial Stiffness in Korean Women and Non-smoking Men

  • Sull, Jae Woong;Koh, Eun Na;Cho, Sung Kweon;Bae, Hyung-Joon;Jee, Sun Ha
    • Biomedical Science Letters
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    • v.23 no.3
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    • pp.201-207
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    • 2017
  • Measuring the pulse wave velocity (PWV) is a non-invasive method for evaluating the stiffness of the vessel wall. While previous studies investigated the association of uric acid level with arterial stiffness, most did not consider smoking status and obesity as covariates. The objective of this study was to investigate the relationship between uric acid levels and arterial stiffness, considering smoking status and obesity. We studied 3390 subjects (1940 males and 1450 females). Abnormal PWV was also defined as the highest quartile of values in the subjects. Data were analyzed using Pearson correlation, t-test, and multiple regression analysis. Approximately 41.9% of men and 3.7% of women were current smokers. Prevalence of hypertension was 11.4% in men and 7.0% in women. In women, hyperuricemia was associated with abnormal PWV (OR 1.58; 95% CI 1.03~2.43). Hyperuricemia was also associated with abnormal PWV (OR 2.37; 95% CI 1.01~5.59) in non- or light male smokers with normal blood pressure. This study suggests that uric acid is associated with arterial stiffness in women and non-smoking men.