• Title/Summary/Keyword: air circulation

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An Effects of Repeated Valsalva Maneuver on Circulation of Normal Men (반복적인 Valsalva Maneuver가 정상인의 순환에 미치는 영향에 관한 연구)

  • 최명애;김종임
    • Journal of Korean Academy of Nursing
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    • v.16 no.1
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    • pp.49-54
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    • 1986
  • As patients on bed rest perform repeated Valsalva maneuver, it is necessary for them to prevent the-danger inherent in repeated Valsalva maneuver through intelligent rehabilitative nursing care. In this regard, it seems to be important to furnish a scientific rationale underlying rehabilitative nursing care. This study was undertaken to find the effects of repeated Valsalva maneuver upon circulation of nor-mal men. The subjects for this study were twenty normal and healthy college students of age from 19 to 26. For the first time, the ECG of standard 12 leads was recorded and the blood pressure was measured under the resting state. And the subjects performed Valsalva maneuver for 10 seconds, then expired air for 2 seconds. After the subjects carried out in this menner for 1 minute, the ECG and the blood pres-sure were recorded and measured again. The Changes of heartbeats, systolic and diastolic pressures after the practice of repeated Valsalva maneuver were compared with those of the letting state. The results obtained were as follows : 1. The heartbeats after the practice of repeated Valsalva maneuver generally increased but did not show statistical significance. 2. The systolic pressure measured after the practice of repeated Valsalva maneuver was higher than that of the resting state. 3. The diastolic pressure measured after the practice of repeated Valsalva maneuver was higher than that of the resting state.

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A Study on Modification of Geographical Features Affecting Onset of Sea Breeze (지형적 특징이 해풍시작에 미치는 영향에 대한 연구)

  • 정우식;이화운
    • Journal of Korean Society for Atmospheric Environment
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    • v.19 no.6
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    • pp.757-772
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    • 2003
  • We simulate the geographical effects on the onset time of sea breeze at Suyoung and Haeundae districts by using the LCM (Local Circulation Model). The following can be found out from the numerical simulation on Case I (real terrain) which considered the real geography of Busan metropolitan area. Especially, as a result of analyzing the land breeze path, it could be found along the coastline as it flows out through low land coastal area. To find out more about the effects of terrain and geography on the onset time of sea breeze, the results of numerical simulation of virtual geography are as follows. In Case II (flat terrain), to find out how the terrain slope affects the onset of sea breeze, flat land and the ocean was considered. As a result, convergence of nighttime air mass at a Suyoung area and nighttime strong wind speed phenomenon was not shown. In Case III (modified flat terrain), to find out the effects of the irregularity of coastline affecting the onset of sea breeze, numerical simulation was carried out by simplifying the complex coastline into segments of straight coastline. So land breeze system and changing process of sea breeze after sunrise at Suyoung and Haeundae was simulated almost in a similar manner. Through this we could find the effects of coastal irregularities on onset of sea breeze.

Treatment of Food Waste Leachate using Pure-Oxygen Jet Loop Reactor(JLR) (순산소 Jet 폭기 시스템을 이용한 음폐수 처리 특성)

  • Yoon, Ae-Hwa;Park, Noh-Back;Bae, Jong-Hun;Jun, Hang-Bae;Kwon, Young-Bae
    • Journal of Korean Society of Water and Wastewater
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    • v.24 no.6
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    • pp.763-773
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    • 2010
  • The removal efficiencies and a total oxygen transfer coefficient for food waste leachate(FWL) were estimated by using Jet Loop Reactor(JLR). Pure oxygen was used instead of air to improve oxygen concentration in the JLR for high total chemical oxygen demamd(TCOD) in FWL. In JLB, in order to examining the oxygen transfer characteristic, the circulation flowrate and oxygen flowrate were controlled with 7~10 L/min(1.5 L/min interval) and 0.2~0.5 L/min (0.1 L/min interval) and we experimented according to the each condition. As a result, Oxygen uptake rate(OUR) and oxygen transfer rate could be maximized than the oxygen flowrate to increase the circulation flowrate. In addition, it determined that JLR using the pure oxygen which can obtain the greatest oxygen transfer rate as it was the high-concentration organic wastewater like the food waste leachate through the continuous experiment was appropriate.

The Heat Exchangers Performance Experiment for a Field Application Ice Slurry Cooling System (현장 적용 아이스슬러리 시스템의 열교환기 성능 실험)

  • Lee, Sang-Hoon;Yoo, Ho-Seon;Lee, Yoon-Pyo
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.1002-1007
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    • 2009
  • The research are performed to check the characteristics of the ice slurry transport system for the district cooling. The system are installed at the 1st floored building which is as large as the $1204\;m^2$ ($86\;m{\times}14\;m$). Three kinds of heat exchanger are selected, such as, plate, spiral and shell & tube type, to apply to the ice slurry systems. Experiment was done in the two cases. The first case, circulation water flow fixed at the design conditions for the state to change the flow of the supply of ice slurry. The second case, Ice slurry flow fixed at the design conditions for the state to change the flow of circulation water. Both side of Energy balance was calculated. The performance of plate heat exchanger is higher than others and it's enthalpy effectiveness is higher too.

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Analysis on the Characteristics of Climate about Korean Summer Season 1998

  • Cha, Eun-Jeong;Choi, Young-Jean;Oh, Jai-Ho
    • International Union of Geodesy and Geophysics Korean Journal of Geophysical Research
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    • v.26 no.1
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    • pp.31-41
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    • 1998
  • The climatic characteristics of summer in 1998 are analyzed with the weather observational data and the upper air observational data. The temperature of that period is lower than that of normal years and the precipitation is larger. Due to the heavy rainfall which started at July 31, rain pured down compared to normal years and the maximum precipitation recorded at the many observational stations, particularly in Seoul, Kyunggi-Do region and mountanious districts like Taegwallyong, Mt. Sokri and Mt. Chiri. The patterns of general circulations in 1982/98 and 1997/98 are compared each other and are analyzed. The anomaly patterns of stream functions on winter in two El Nio years are simialr. The counterclockwise circulation occurred near the date line and the clockwise circulation was appeared near the Hwanam region and Alaska. These patterns are opposite to those of La Nia year, 1988/89. And the anomaly patterns of 500hPa geopotential height in summer are similar, too. The low temperature and much rain were dominated in summer of 1997/98. These phenomena is similar to the existing results of research, that temperature is low and precipitation is large in summer of El Nio years.

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Study on an Electrode Attachment Method Suitable for Underwater Electromyography Measurements

  • Han, Seul-ki;Park, Jung-seo;Nam, Taek-gil
    • Journal of the Korean Society of Physical Medicine
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    • v.10 no.2
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    • pp.95-98
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    • 2015
  • PURPOSE: This study was conducted to devise a method of preventing water infiltration into the surface electrodes during EMG measurements underwater and on the ground and to check the reliability of Electromyography (EMG) measurements when underwater. METHODS: Six healthy adults were selected as subjects in this study. The measurements in this study were conducted in pool dedicated to underwater exercise and physical therapy room in the hospital building. An MP150 (Biopac Systems, US, 2010) and a BioNomadix 2-channel wireless EMG transmitter (Biopac Systems, US, 2012) was used to examine the muscle activity of rectus femoris, biceps femoris, tibialis anterior, gastrocnemius of dominant side. The subjects repeated circulation tasks on the ground for more than 10 min for enough surface electrode attachment movement. After a 15-min break, subjects performed the circulation task underwater(water depth 1.1m, water temperature $33.5^{\circ}C$, air temperature $27^{\circ}C$), as on the ground, for more than 10 min, and the MVIC of each muscle was measured again. SPSS v20.0 was used for all statistical computations. RESULTS: The maximum voluntary isometric contraction (MVIC) values between the underwater and on the ground measurements showed no significant differences in all four muscles and showed a high intraclass correlation coefficient (ICC) of >0.80. CONCLUSION: We determined that EMG measurements obtained underwater could be used with high reliability, comparable to ground measurements.

Numerical and Experimental Study on the Fire Whirl Characteristics of Oriental Oak Leaves (굴참나무 낙엽의 Fire Whirl 특성에 관한 실험 및 수치해석 연구)

  • Bae, Sung-Yong;Ryou, Hong-Sun;Hong, Gi-Bae
    • Fire Science and Engineering
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    • v.23 no.3
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    • pp.73-78
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    • 2009
  • The fire whirl occurring in the urban and/or wildland fire is generated by the instabilities of atmosphere. The fire whirl is a rare phenomenon, but highly destructive because it has high inhalation and lift force. In this study, experimental and numerical studies are performed with oriental oak leaves, for investigating of the fire whirl characteristics occurred in wildland fire. As a result of experiment, the circulation intensity increases as the induced air speed increases, then the heat release rate and flame height increase 22.8%, 18.4% compared with open fire in highest circulation. Furthermore the numerical results shows same trend with the experiment.

Comparison on Safety Features among HTGR's Reactor Cavity Cooling Systems (RCCSs)

  • Kuniyoshi Takamatsu;Shumpei Funatani
    • Nuclear Engineering and Technology
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    • v.56 no.3
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    • pp.832-845
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    • 2024
  • Reactor cavity cooling systems (RCCSs) comprising passive safety features use the atmosphere as a coolant, which cannot be lost. However, their drawback is that they are easily affected by atmospheric disturbances. To realize the commercial application of the two types of passive RCCSs, namely RCCSs based on atmospheric radiation and atmospheric natural circulation, their safety must be evaluated, that is, they must be able to remove heat from the reactor pressure vessel (RPV) surface at all times and under any condition other than under normal operating conditions. These include both expected and unexpected natural phenomena and accidents. Moreover, they must be able to eliminate the heat leakage emitted from the RPV surface during normal operation. However, utilizing all of the heat emitted from the RPV surface increases the degree of waste heat utilization. This study aims to understand the characteristics and degree of passive safety features for heat removal by comparing RCCSs based on atmospheric radiation and atmospheric natural circulation under the same conditions. It was concluded that the proposed RCCS based on atmospheric radiation has an advantage in that the temperature of the RPV could be stably maintained against disturbances in the ambient air.

Experimental Study on Wave Attenuating Effect of a Pneumatic Breakwater by Using a Multiple Parallel Manifold (다중 병렬 분기관을 이용한 압축공기 방파제의 소파효과에 관한 실험적 연구)

  • KIM JONG-WOOK;Shin Hyun-Soo
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2004.05a
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    • pp.257-262
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    • 2004
  • A series of preliminary model tests are performed to find out the wave attenuating effect of the pneumatic breakwater of environment friendly type, which is a bubble screen generated by releasing compressed air from a submerged multiple parallel manifold Rising bubbles induce vertical current, which produces horizontal currents flowing away from the bubble-screen area in both directions. Near bottom, the corresponding currents flow toward the bubble screen, thus completing the circulation pattern. The surface current moving against the direction of wave propagation causes some attenuation of the waves. It becomes more effective as the relative depth (d/ L) increases (short-period waves in deep water). With the same air-discharge, the multiple parallel manifold can be more effective for the attenuation of longer waves through optimum arrangement of manifold number. installation depth, manifold gap, etc. The pneumatic breakwater will give a wide utilization as a device for protecting harbor facilities and as a simple, mobile breakwater.

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A study for Ripple effect and Dye Characteristic of Ripple Finished Cotton Fabrics (Ripple가공(加工) 면직물(綿織物)의 Ripple효과(效果)와 꼭두서니염색(染色) 연구(硏究))

  • Choi, Jeong-Im;Kim, Jong-Jun;Jeon, Dong-Won
    • Journal of Fashion Business
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    • v.11 no.4
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    • pp.101-110
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    • 2007
  • Since cotton fabrics with ripple finish treatment form wavy furrows on the surface or bumpy patterns, air circulation during wearing is good and the fabric is cool to the touch. The finishing principle is based on the mercerization, which utilizes the fact that cotton fibers contract in a concentrated NaOH solution. In this study, as fabric specimens, cotton fabrics with yarn counts of 40's, 60's and 80's were used. Concentrations of the NaOH solutions were 15%, 25%, and 35%. After dyeing fabrics using Rubia akane nakai, color and other properties were measured. As the concentration of the NaOH solution increased, the fabric became thicker and denser, and the number of occurrence of the prominence and depression per unit length became larger. The color of the region contracted by ripple finish became darker after dyeing, while the color of the untreated region became lighter, which enhanced the cubic effect of the ripple finish. As the count of the cotton yarn increased, the dyeability became better. As the concentration of the NaOH solution increased, the air permeability became lower.