In this study, we propose a flow velocity evaluation scheme based on pressure measurement in pressurized pipeline systems. Conservation of mass and momentum equations can be decomposed into mean and perturbation of pressure head and flowrate, which provide the pressure head and flowrate relationship between upstream and donwstream point in pressurized pipeline system. The inverse impedance formulations were derived to address measured pressure at downstream to evaluation of flow velocity or pressure at any point of system. The convolution of response function to pressure head in downstream valve provides the flow velocity response in any point of the simple pipeline system. Simulation comparison between traditional method of characteristics and the proposed method provide good agreements between two distinct approaches.

Background: Due to aging, blood flow rate decreases, also posture and chewing habit may be changed. Objective: To identify that changes in blood velocity in the common carotid arteries (CCAs) in old persons with unilateral chewing habit (UCH) and forward head posture (FHP) in the elderly. Design: An observational cross-sectional study. Methods: Chewing habits, FHP, and CCAs velocities were assessed in 85 elderly subjects. Chewing habits were measured by visual observation. CCAs measured the peak systolic velocity (PSV), end-diastolic velocity (EDV), minimum diastolic velocity, and resistivity index. The subjects were divided into UCH and bilateral chewing habit groups depending on chewing habit. The subjects were also divided into >49 degrees and <49 degrees for comparison of blood flow between the left and right CCAs. Results: In the UCH, the chewing side had significantly higher EDV (P=.003), PSV (P=.023) than the non-chewing side. There was no significant difference in velocity between the CCAs in the FHP. Conclusion: This study shows that the blood flow velocity of the chewing side of UCH was higher, and unilateral chewing affects the CCAs velocity and thus highlight the importance of chewing habit in the elderly than head posture.

본 연구는 난방온실의 온도분포 균일화를 위한 기초자료 제공을 목적으로 온수난방 방식의 토마토 재배 온실 에서 난방실험을 통하여 난방배관의 표면온도와 실내기온 사이의 상관관계를 분석하고, 난방배관의 열전달특성 분석과 난방배관 배치의 개선을 통하여 난방배관 표면온도의 편차를 줄이고 균일도를 향상시키기 위한 방안을 도출하였다. 서로 다른 두 온실의 온도분포를 분석하여 최대편차와 균일도를 검토한 결과, 온수의 유량이 많고 난방배관의 길이가 짧게 배치된 온실의 온도편차가 작고, 균일도는 높은 것으로 나타났다. 또한 순환팬을 가동한 경우에 온도편차는 작아지고 균일도가 개선되는 것을 확 인할 수 있었다. 난방배관의 표면온도와 실내기온 사이의 상관관계를 분석한 결과, 두 온실 모두에서 유의적인 (p<0.01) 정적 상관관계가 있는 것으로 나타났다. 온수난방 온실에서 실내기온의 분포는 난방배관 표면온도의 분포에 영향을 받는다는 것을 확인할 수 있었고, 온도편차 가 최소화 되도록 난방배관을 배치함으로써 실내기온 분포의 균일도를 개선할 수 있는 것으로 판단되었다. 난방 배관의 열전달 특성을 분석한 결과 배관의 길이가 길어 지면 온도편차는 커지고, 관내의 유속이 빨라지면 온도 편차는 작아지는 것으로 나타났다. 따라서 지선배관의 길이가 짧아지도록 난방배관을 배치하고, 관내의 유속을 제어함으로써 온실의 온도분포와 환경의 균일성을 개선 할 수 있을 것으로 판단되었다. 국내 온실에서 가장 많 이 사용하고 있는 튜브레일(40A) 방식의 온수난방시스 템에서 하나의 지선배관에서의 온도편차를 3oC 이내로 조절하기 위해서는 관내의 유속이 0.2, 0.4, 0.6, 0.8, 1.0m·s-1일 때 난방배관의 길이는 각각 40, 80, 120, 160, 200m 이내로 제한해야 하는 것으로 분석되었다.

하천의 생태 환경적인 측면을 고려하여 여러 가지 친환경적인 호안공법이 적용되어 시공되는 사례가 증가하고 있다. 친환경적인 호안공법으로는 식생공이 대표적이나 중량물을 시공하는 호안공법과 달리 식생매트를 고정핀으로 고정하는 방식의 식생매트와 같은 호안공법의 경우 중량물을 설계하는 여타의 공법과 달리 적합한 설계방법이 없어 경험적인 방법을 통해서 제 품의 개발과 시공이 이루어지고 있는 실정이다. 따라서 본 연구에서는 식생매트공법에 사용되는 고정핀과 고정핀이 정착된 지반을 모델링하고 유한요소법을 활용하여 호안식생매트의 안전성을 평가하였다. 해석결과 핀의 상단 부분에서 인발에 저항하기 위해 인장응력이 유발되고 있으며, 헤드 부분은 거의 응력이 작용하지 않는 것으로 나타났고, 핀의 Von Mises 응력값이 인장강 도에 비해 낮게 나타나 파괴모드가 재료 자체의 항복 또는 파쇄에 의한 파괴가 아닌 핀과 지반사이의 뽑힘이 전체 거동을 지배 한다고 평가하였다. 본 연구는 유한요소법을 통해서 식생매트공법의 안전성을 변위와 발생응력에 대하여 평가하였다.

Recently, copper alloy netting has been proposed as a material for aquaculture facilities that can be set in harsh offshore environments. To design a cage made of copper alloy netting, it is necessary to calculate the flow of water through the netting and force of external sources on the netting. Therefore, this study measured and analyzed the current velocity reduction after passing through the netting and the hydrodynamic forces acting on the netting using copper alloy netting with nine solidity ratios. As a result of the reduction rate of the flow velocity through the netting, the flow reduction rate was increased as the solidity ratio of netting was increased. The flow reduction rate was also increased as the attack angle on the netting was decreased. In analyzing the resistance on the netting, we also discovered that resistance was increased with increase in the flow velocity and solidity ratio. An analysis of the hydrodynamic coefficient acting on the netting is shown that the drag coefficient tends to increase as the attack angle increases. We also analyzed the hydrodynamic coefficient according to the variation of the Reynolds number. When the drag coefficients acting on the netting were analyzed with the different Reynolds numbers, the Reynolds number increased from over 0.3 m/s to a relative constant. Finally, the copper alloy nettings had a smaller velocity reduction rate when comparing the flow velocity reduction rate between copper alloy nettings and nylon nettings.

층면구조 안정성 다이어그램은 층면구조가 주어진 입도와 유속에서 나타나는 층면구조의 모양과 크기를 지시한다. 이 다이어그램은 대부분 수조실험에 의해 획득한 실험 데이터를 기반으로 작성되었다. 일반적으로, 수조실험은 입자의 크기와 유속사이의 관계를 이해하기 위해 분급이 좋고 단일입도의 분포를 보이는 퇴적물을 이용하여 수행되었다. 이 다이어그램에 의하면, 세립사와 중립사 퇴적물 표면에서 유속이 빨라지면서, 평행층에서 연흔이 형성되기 시작한다. 이 연구의 목적은 층면구조 안정성 다이어그램의 결과가 실험을 통하여 잘 재현되는지를 확인하고, 분급이 좋은 퇴적물과 달리 분급이 불량한 경우인 이정 입도 분포를 보이는 사질 퇴적물에서도 잘 재현되는지 확인하는 것이다. 본 연구 실험 결과는 2D 연흔이나 3D 연흔 층면구조가 형성되기 위해서, 분급이 불량한 퇴적물의 경우에, 분급이 좋은 퇴적물보다 더 높은 유체의 유속과 전단응력이 필요하다는 것을 보여주고 있다. 탄산염 퇴적물은 수력학적 분급작용이 활발하지 않으며, 퇴적물의 구성이 알로켐과 기질로 이루어지는 이정 입도 분포를 보이는 퇴적물로서 일반적으로 분급이 불량한 특징을 가지고 있다. 따라서, 실험의 결과는 탄산염 퇴적물에서 층면구조 형성을 위해 쇄설성 퇴적환경의 퇴적물 보다 더 높은 유속이 필요할 수 있음을 제안하고 있다. 분급이 불량한 퇴적물 입자가 침식되어 이동기 위해 더 높은 에너지와 유속이 필요하다는 것은 분급 효과, 마찰 효과, 안정성 효과, 갑옷 효과 등이 복합적으로 작용한 결과로 설명될 수 있을 것이다. 본 연구는 예비적 고찰로서, 이어지는 연구를 통해 이러한 현상을 과학적으로 설명하고 입도와 층면구조 형성의 상관성을 보다 정교하게 규명하고자 한다.

To perform long-term sewer monitoring, It is important to understand the nature of the wastewater flow that occurs at the point on early stage of the monitor and to prevent in advance a problem which may caused. We can infer the flow properties and external factors by analyzing the scatter graph obtained from the measured data flow rate monitoring data since an field external factor affecting the sewage flow is reflected in the flow rate monitoring data. In this study, Selecting the three points having various external factors, and we Inferred the sewer flow characteristics from depth-velocity scatter graph and determined the analysis equation for the dry-weather flow rate data. At the‘point 1’expected non-pressure flow, we were able to see the drawdown effect caused by the free fall in the manhole section. At the‘point 2’, existed weir and sediments, there was backwater effect caused by them, and each of size calculated from the scatter graph analysis were 400 mm and 130 mm. At the‘Point 3’, there is specific flow pattern that is coming from flood wave propagation generated by the pump station at upstream. In common, adequate equations to explain the dry weather flow data are flume equation and modified manning equation(SS method), and the equations had compatibility for explaining the data because all of R2 values are over 0.95.

A 2D axisymmetric numerical analysis was performed to study the characteristics of charge process inside solar thermal storage tank. The porosity and heat transfer coefficient of filler material as well as inlet velocity of heat transfer fluid are selected as simulation parameters. The porosity is varied as 0.2, 0.5, and 0.8 to account for the effect of filler granule geometry. Two levels of the heat transfer coefficient is adopted to assess the heat transfer between heat transfer fluid and filler material. The inlet velocity is varied as 0.00278, 0.0278, and 0.278m/s. As both of the porosity and the heat transfer coefficient increase, the discrepancy of the temperature distributions between the filler and heat transfer fluid decreases. As the inlet velocity increases, the penetration depth of the heat transfer fluid increases proportionally.

Vacuum kinetic spray(VKS) is a relatively advanced process for fabricating thin/thick and dense ceramic coatings via submicron-sized particle impact at room temperature. However, unfortunately, the particle velocity, which is an important value for investigating the deposition mechanism, has not been clarified yet. Thus, in this research, VKS average particle velocities were derived by numerical analysis method(CFD: computational fluid dynamics) connected with an experimental approach(SCM: slit cell method). When the process gas or powder particles are accelerated by a compressive force generated by gas pressure in kinetic spraying, a tensile force generated by the vacuum in the VKS system accelerates the process gas. As a result, the gas is able to reach supersonic speed even though only 0.6MPa gas pressure is used in VKS. In addition, small size powders can be accelerated up to supersonic velocity by means of the drag-force of the low pressure process gas flow. Furthermore, in this process, the increase of gas flow makes the drag-force stronger and gas distribution more homogenized in the pipe, by which the total particle average velocity becomes higher and the difference between max. and min. particle velocity decreases. Consequently, the control of particle size and gas flow rate are important factors in making the velocity of particles high enough for successful deposition in the VKS system.

음식물 폐기물 침출수를 처리하는 분리막 결합 고온 혐기성소화공정(생물학적 반응조) (Anaeorobic Membrane Bioreactor, AnMBR)의 파일럿 운전에서 분리막의 교차여과 속도와 막간압력이 파울링에 미치는 영향을 관찰하였다. 연구 결과 정압여과 하에서 교차여과 속도가 증가할수록 파울링의 속도는 현격히 감소되었다. 그러나 이와 같은 영향은 낮은 막간압력에서 더욱 효과적이었다. 막간압력이 증가할수록 여과대상 물질의 압축성으로 인해 투과성이 상대적으로 낮은 파울링층(혹은 케익층)이 분리막 표면에 형성된 것에 기인된 듯하다. 여과대상 시료의 입도분석을 해 본 결과 입자크기는 약 10~100mum 범위에서 분포하였고 이에 따라 브라운확산에 의한 역수송보다 분리막 표면에서 교차여과에 의해 발생하는 전단력이 입자의 역수송에 더욱 기여하고 있음을 예측할 수 있었으며 이는 AnMBR의 연속운전을 통해 재확인할 수 있었다. 운전 후 막 부검을 실시한 결과 유기 및 무기 파울링이 모두 관찰되었으나 어느 것이 지배적인 파울링 기작을 나타내는지는 앞으로 더욱 연구가 필요하다. 무기 파울링의 경우 대부분 분리막 표면에서 스케일링 형성이 지배적이었으며, 따라서 분리막의 공극 막힘에 주로 기여하는 작은 콜로이드성 유기물질의 경우 분리막 표면에서 전단력에 의한 역수송 효과는 그다지 크지 않을 것으로 사료된다.

The purpose of this study was to identify the effects of manipulation on the velocity of cerebral blood flow and level of pain in cervicogeinc headache patients. The velocity of cerebral blood flow of 30 cervicogeinc headache patients(male=15, female=15, age=24.00±3.60) and 33 normal subjects(male=15, female=18, age=23.27±3.00) was compared. The 30 cervicogeinc headache patients were divided into suboccipitalis relaxation group, cervical manipulation group, and placebo group, and each were given different interventions. The velocity of cerebral blood flow and pain level was measured before intervention, and 1, 2, 3 weeks after intervention. The velocity of cerebral blood flow was measured with the Transcranial Doppler(TCD), and pain level was measured with visual analog scale(VAS). Blood flow velocity of middle cerebral artery in cervicogeinc headache patients was slower than those in healthy subjects. Physical therapy intervention did not have significant effect on velocity of cerebral blood flow, but slowly decreased at intervention for pain level increased. The suboccipitalis relaxation group and cervical manipulation group showed significant effect in decreasing pain level compared to the placebo group(p＜.05). Directly applied manipulation therapy in the neck area not only has effect on joint of cervical and soft tissue but also on blood vessels and nerves which pass the neck area, and because of those results of manual therapy seems to help recovery.

This paper is development of Surface Flow PIV for velocity measurement of surface flow. The new Velocity measurement method for surface flow using video-taped images is presented. Velocity distributions are calculated by the correlation method after the transformation of images to the non-distorted ones. The method to transform oblique-angled images to normal ones as well as its accuracy is discussed in detail. In this study, we carried out velocity measurement of an ocean current velocity distribution of saemangeum sea-wall model using Surface Flow PIV.

This fundamental studies on for the productivity improvement and laborsaving of purse seine fishery. Given the difficulty posed from the distortion of net shape caused by the external forces, such as tide, at the time of shooting and pursing, we set the 4 steps of 0, 2, 4 and 6cm/sec in flow velocity in the flume tank for the experiment in order to examine those characteristics. We used two model seines designed on the scale of 1 to 180 based on the power block seine, which is the mackerel purse seine generally used in the near sea of Jeju Island and triplex seine, which is the mackerel purse seine of one boat system fishing expected in the future, for the experiment, and interpreted the characteristics of several motion in water, such as the shape of seine, the change in tension and area during pursing and its the analysis results are as follows. Though the experiment could be conducted up to 6cm/sec of flow velocity that was defined, the experiment could not go on because of the severe distortion in the seine at the flow velocity in excess of 6cm/sec. As for the depth of leadline and reduction rate of side area of seine when the pursing is connected, P seine turned out to be slightly higher than T seine, and the hauling speed and reduction rate of upper area of seine were found similar to each other. The correlation between the hauling time (Ht) and depth of lead line (Dhp, Dht) of P seine and T seine can be expressed by the equation, that is, Dhp=(0.99Pt-7.63)Pt+69.01, Dht=(1.03Pt-7.73)Pt+66.74. The correlation between the hauling time and hauling velocity (Hpp, Hpt) can be expressed by the equation, that is, Hpp=-0.06Ht2+0.88Ht+0.78, Hpt=-0.05Ht2+0.81Ht+0.98 here, Pt is pursing time. And the correlation between the pursing time and the reduction rate of side area (sArp, sArt) can be expressed by the equation, that is, sArp=-0.48Pt2+14.79Pt-16.74, sArt=-0.45Pt2+14.56Pt-16.48. The reduction rate of upper area of seine (tArp, tArt) can be expressed by the equation, that is, tArp=0.34Pt2-0.66Pt-0.74, tArt=0.34Pt2-0.27Pt-1.80. In addition, the correlation between the pursing time and tension of purse line (Tep, Tet) can be expressed by the equation, that is, Tep=2.79Pt2+2.26Pt-0.60, Tet=2.14Pt2+8.08Pt-27.50.

It is the basic studies for productivity improvement and laborsaving of purse seine fishery. Because the seine shape is apt to be transformed in seine shooting process due to the effect of tide, this study is intended to establish 4 steps, whose flow velocity are 0, 2, 4 and 6cm/sec, in flume tank and perform the experiment to review the character. We used two model seines designed on the scale of 1 to 180 based on the power block seine, which is the mackerel purse seine generally used in the near sea of Jeju Island and triplex seine, which is the mackerel purse seine of one boat system fishing expected in the future, for the experiment, analyzed of the sinking movements on the two seines and its results are as follows. In the setting over the flow velocity 6cm/sec, experiment was impossible because of flying and transformation of seine were severe. The sinking movements of P seine and T seine generally showed linear phenomenon and the sinking speed showed gentle curve shape. Sinking tendency was distinguished by existence of flow velocity. When there is flow velocity, it showed the phenomenon that it sinking by similar type. Although sinking depth and sinking speed did not show distinguished classification, P seine shows bigger than T seine. When there was in flow velocity, the elapsed time(Et) and sinking depth (PDp, TDp) of P seine and T seine can be shown such experimental equations as PDp=(0.21V+4.96)Et-(0.62V-0.10) and TDp=(0.19V+4.95)Et-(0.72V+0.34). When there was in flow velocity, the elapsed time and siking speed (PSp, TSp) of P seine and T seine can be shown such experimental equations as PSp=-0.11Et2+1.42Et+1.75 and TSp=-0.11Et2+1.41Et+1.37.

This study was conducted to determine the effects of deep breathing exercise and ankle exercise on blood flow velocity in the femoral vein. Sixteen healthy male students were recruited from Yonsei University, at Wonju. The blood flow velocities in the femoral vein were measured under three different conditions: resting, deep breathing, and ankle exercise. All subjects were given a 5-minute relaxing time in supine position prior to the study. Using a doppler ultrasound with a 8 MHz probe, the peak blood flow velocities were collected in a twenty-second-period at each condition. The subjects took a rest in between trials for the blood flow to return to its resting levels. The result showed a significant difference in peak blood flow velocities under those three conditions (p<.001). The peak blood flow velocity was highest in ankle exercise condition. The peak blood velocity was significantly higher in deep breathing condition compared with the resting condition. As a result, it is revealed that not only the muscular contractions but also the deep breathing exercises induced facilitating effects of venous return. Either of the exercise methods can be recommended to prevent blood stasis in patients with risk of deep vein thrombosis after cardiac or lower extremity surgery.ㅂ

1999년 5월 29일부터 6월 30일까지의 남해안에서의 수심에 따른 수중광의 변화와 조업시간의 경과에 따른 예망 상대유속을 측정하고, 권현망어구에 대한 체장 4~7cm정도 되는 멸치들의 도피 반응행동을 관찰하고 분석한 결과는 다음과 같다. 1) 남해안 통영, 거제 부근 멸치어장에서 수심에 대한 수중광의 변화를 자연대수 곡선식으로 나타내면 광흡수 계수 c는 대표적인 관측점에서 주로 0.24~1.03 범위로 나타나서, 멸치의 어구에 대한 시인도가 어장에 따라 클 것으로 보인다. 2) 권현망어구의 원형그물과 1/2축소그물의 자루그물 입구부분의 상대유속을 기준으로 할때, 수비와 자루의 연결부분의 유속비는 평균 1.46, 자루부분의 유속비는 평균 0.67로 나타나서, 어구의 부위에 따른 상대유속변화가 멸치의 유영운동과 도피운동에 영향을 줄 것으로 보인다. 축소된 권형망어구에 있어서의 멸치의 대망행동을 관찰한 결과 수비와 자루연결부분에서 빠져나가는 1분당 멸치도피수는 평균 455미 정도였으며, 자루의 앞에서 예인방향으로 유영하는 깔대기를 빠져나가는 1분당 멸치도피 수는 평균 308미 정도로 나타나서, 어구 전체적으로는 상당수의 멸치들이 능동적인 도피행동을 나타내는 것으로 추측된다.