• 제목/요약/키워드: surface pressure measurement

검색결과 485건 처리시간 0.028초

DI 디젤기관 실린더 헤드표면의 순간온도 및 열유속 측정에 관한 실험적 연구 (An Experimental Study on the Measurement of Instantaneous Surface Temperature and Heat Flux on the Cylinder Head Surface of DI Diesel Engine)

  • 이재순;김기태;이현구;강태경;우종헌;김수성
    • 한국자동차공학회논문집
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    • 제5권5호
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    • pp.178-187
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    • 1997
  • For the experimental measurement of heat flux of DI diesel engine combustion chamber, the instantaneous temperature probes and data acquisition system were developed. By the analysis of measured temperatures at the cylinder head, the temperature at the point 3 which is located between intake and exhaust valve was higher than that of the other points. Temperatures at the point located mear the exhaust valve were higher than those of intake valve. The instantaneous and mean temperature at the cylinder head increases proportionally to the increase of the engine speed, while the temperature swing varies inversely. Temperature swings have influence on the maximum heat flux values from gas into head surface. It has been verified that these probes and data acquisition system perform well by the comparison of the trend of instantaneous temperature variation with that of measured combustion chamber pressure variation with respect to crank angle. It is presumed that these probes could be used in the measurement of other parts of combustion chamber as piston, cylinder wall etc. for the future study.

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Measurement of Hydroxyl Radical Density at Bio-Solutions Generated from the Atmospheric Pressure Non-Thermal Plasma Jet

  • Kim, Yong Hee;Hong, Young June;Uhm, Han Sub;Choi, Eun Ha
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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    • pp.494-494
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    • 2013
  • Atmospheric pressure non-thermal plasma of the needle-typed interaction with aqueous solutions has received increasing attention for their biomedical applications [1]. In this context, surface discharges at bio-solutions were investigated experimentally. We have generated the non-thermal plasma jet bombarding the bio-solution surface by using an Ar gas flow and investigated the emission lines by OES (optical emission spectroscopy) [2]. Moreover, The non-thermal plasma interaction with bio-solutions has received increasing attention for their biomedical applications. So we researched, the OH radical density of various biological solutions in the surface by non-thermal plasma were investigated by Ar gases. The OH radical density of DI water; deionized water, DMEM Dulbecco's modified eagle medium, and PBS; 1x phosphate buffered saline by non-thermal plasma jet. It is noted that the OH radical density of DI water and DMEM are measured to be about $4.33{\times}1016cm-3$ and $2.18{\times}1016cm-3$, respectively, under Ar gas flow 250 sccm (standard cubic centimeter per minute) in this experiment. The OH radical density of buffer solution such as PBS has also been investigated and measured to be value of about $2.18{\times}1016cm-3$ by the ultraviolet optical absorption spectroscopy.

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Pressure distribution and aerodynamic forces on stationary box bridge sections

  • Ricciardelli, Francesco;Hangan, Horia
    • Wind and Structures
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    • 제4권5호
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    • pp.399-412
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    • 2001
  • Simultaneous pressure and force measurements have been conducted on a stationary box deck section model for two configurations (namely without and with New Jersey traffic barriers) at various angles of incidence. The mean and fluctuating aerodynamic coefficients and pressure coefficients were derived, together with their spectra and with the coherence functions between the pressures and the total aerodynamic forces. The mean aerodynamic coefficients derived from force measurements are first compared with those derived from the integration of the pressures on the deck surface. Correlation between forces and local pressures are determined in order to gain insight on the wind excitation mechanism. The influence of the angle of incidence on the pressure distribution and on the fluctuating forces is also analysed. It is evidenced how particular deck section areas are more responsible for the aerodynamic excitation of the deck.

골프선수의 3차원적 척추구조, 골반변위 및 족압에 관한 연구 (A Study on the Structure of Three Dimentional Spine, Pelvic Deviation and Foot Pressure in Golf Players)

  • 양대중
    • 한국운동역학회지
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    • 제22권2호
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    • pp.151-158
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    • 2012
  • The purpose of this study was to investigate variables of significantly difference as the structure of the spine, pelvic deviation and foot pressure between undergraduates and golf player subjects. The subjects of study were composed of 20 male golf players and 20 male undergraduates. Both groups were right handed persons. The measurement tools of this study were Formetric 4D(Diers, Germany) which is a three dimensional measure. The result are the follows: there were a significant difference between golf players and general students of trunk imbalance, pelvic tilt, pelvic torsion, pelvic rotation, surface rotation, lumbar lordotic curve, foot pressure(fore & behind foot), weight distribution(right & left foot). In conclusion, golf players might cause transform of spine and foot pressure due to golf exercise for several years. Such as imbalance affect to induce functional impairment and pain of musculoskeletal system, and appropriate evaluation and treatment were necessary for golf players.

Flexible wireless pressure sensor module

  • Shin Kyu-Ho;Moon Chang-Ryoul;Lee Tae-Hee;Lim Chang-Hyun;Kim Young-Jun
    • 한국마이크로전자및패키징학회:학술대회논문집
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    • 한국마이크로전자및패키징학회 2004년도 추계 기술심포지움 초록집
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    • pp.3-4
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    • 2004
  • A flexible Packaging scheme, which embedded chip packaging, has been developed using a thinned silicon chip. Mechanical characteristics of thinned silicon chips are examined by bending test and finite element analysis. Thinned silicon chips ($t<50{\mu}m$) are fabricated by chemical etching process to avoid possible surface damages on them. These technologies can be use for a real-time monitoring of blood pressure. Our research targets are implantable blood pressure sensor and its telemetric measurement. By winding round the coronary arteries, we can measure the blood pressure by capacitance variation of blood vessel.

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압력면익단소익이 터빈 동익 압력면스퀼러팁 하류의 팁누설유동 및 압력손실에 미치는 영향 (Effects of Pressure-Side Winglet at an Elevation of Tip Surface on the Tip-Leakage Flow and Aerodynamic Loss Downstream of a Turbine Blade Equipped with Pressure-Side Squealer Tip)

  • 천주홍;이상우
    • 대한기계학회논문집B
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    • 제40권10호
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    • pp.645-651
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    • 2016
  • 본 연구에서는 압력면익단소익의 폭이 터빈 동익 압력면스퀼러팁 하류의 팁누설유동 및 압력손실에 미치는 영향에 대하여 연구하였다. 팁간극비 h/s = 1.36%에 대하여, 흡입면스퀼러의 높이는 $h_p/s=3.75%$로 일정하게 유지하고, 압력면익단소익의 폭은 w/p = 2.64%, 5.28%, 7.92%, 10.55% 등으로 변화시키면서 실험을 수행하였다. 일반적으로 압력면익단소익의 폭이 증가할수록, 통로와류 영역에서의 압력손실은 감소하였지만 팁누설유동 영역에서는 압력손실이 오히려 증가하였다. 그 결과 익단소익의 폭이 증가할수록, 질량평균 압력손실은 매우 소폭 감소하는 경향을 보였다. 본 연구 결과, 압력면스퀼러팁에 설치된 압력면익단소익은 압력손실 저감에 거의 기여를 하지 못함을 확인할 수 있었다.

Patellofemoral contact mechanics after transposition of tibial tuberosity in dogs

  • Park, Donghee;Kang, Jinsu;Kim, Namsoo;Heo, Suyoung
    • Journal of Veterinary Science
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    • 제21권4호
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    • pp.67.1-67.11
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    • 2020
  • Background: Tibial tuberosity transposition (TTT) causes caudalization of the patellar ligament insertion in canine medial patellar luxation, which can lead to increases in patellofemoral contact pressure. Objectives: The purpose of this study is to confirm the effect of patellofemoral contact mechanics after craniolateral and caudolateral transposition of tibial tuberosity in normal canine hindlimbs. Methods: Craniolateral and caudolateral transposition of tibial tuberosity was performed in 5 specimens, respectively. The pressure was measured in the specimen before TTT, and then in the same specimen after TTT. In this process, data was obtained in 10 specimens. The measurement results were output as visualization data through the manufacturer's software and numerical data through spreadsheet. Based on these 2 data and the anatomical structure of the patellofemoral joint (PFJ) surface, whole measurement area was analysed by dividing into medial, lateral and central area. Results: In craniolateralization of tibial tuberosity, total, medial, central contact pressure was decreased and lateral contact pressure was not statistically changed lateral contact pressure than normal PFJ. In caudolateralization of tibial tuberosity, total, lateral contact pressure was increased and medial contact pressure was not statistically changed than normal PFJ. Although not statistically significant changed, central contact pressure in caudolateralization of tibial tuberosity was increased in all 5 specimens. Conclusions: These results imply that traditional TTT, prone to caudal shift of patellar tendon, can increase retropatellar pressure may lead to various complications and diseases of the stifle joint.

PSP 압력측정 시스템의 구축 (Construction of the Pressure Sensitive Paint System)

  • 전영진;김기수;서형석;변영환;이재우
    • 한국추진공학회지
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    • 제12권1호
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    • pp.7-15
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    • 2008
  • Pressure Sensitive Paint(PSP)는 압력에 반응하는 도료를 뜻한다. PSP를 이용하여 압력을 측정하기 위해서는 Paint Calibration과 PSP를 도포한 모델의 풍동실험이 필요하다. PSP는 이 두 가지의 결과를 이용한 이미지의 후처리과정을 통하여 압력정보를 포함한 이미지를 얻을 수 있는 신기술이다. 본 연구에서는 PSP에 필요한 장치 및 설비들을 구성하고 PSP를 이용하여 초음속 유동장 내의 압력측정 실험을 실시하였다. 압력측정 실험은 초음속 유동장의 노즐 벽면의 압력을 측정하였으며, 측정 압력에 대해서는 압력공(Pressure Tap)에 의한 결과값과 전산해석의 결과값을 통하여 비교하였고, 그 실험 결과를 바탕으로 PSP는 표면압력을 측정함에 있어서 압력공을 이용한 기존의 방식을 대체할 수 있는 기술임을 확인하였다.

Semi-spade 타의 간극 캐비테이션에 대한 실험적 연구 (Experimental Investigation on the Gap Cavitation of Semi-spade Rudder)

  • 백부근;김경열;안종우;김용수;김성표;박제준
    • 대한조선학회논문집
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    • 제43권4호
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    • pp.422-430
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    • 2006
  • The horn and movable parts around the gap of the conventional semi-spade rudder are visualized by high speed CCD camera with the frame rate of 4000 fps (frame per second) to study the unsteady cavity pattern on the rudder surface and gap. In addition, the pressure measurements are conducted on the rudder surface and inside the gap to find out the characteristics of the flow behavior. The rudder without propeller wake is tested at the range of $1.0{\leq}{\sigma}_v\;1.6$ and at the rudder deflection angle of $-8{\leq}{\theta}{\leq}10^{\circ}$. The time resolved cavity images are captured and show strong cavitation around the rudder gap in all deflection angles. As the deflection angle gets larger, the flow separated from the horn surface increases the strength of cavitation. The accelerated flow along the horn decreases its pressure and the separated flow from the horn increases the pressure abruptly. The pressure distribution inside the gap reveals the flow moving from the pressure to suction side. In the negative deflection angle, the turning area on the movable part initiates the flow separation and cavitation on it.

접수 원통형 구조물의 표면 진동속도를 이용한 총 방사음향파워 계산 (Estimation of Total Acoustic Radiation Power of Submerged Circular Cylindrical Structure Using Surface Vibration Velocity)

  • 한승진;이종주;강명환;배수룡;정우진
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2014년도 추계학술대회 논문집
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    • pp.236-239
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    • 2014
  • Most naval underwater weapon system can be simplified to a circular cylindrical structure which has vibrating machineries inside. In order to predict efficiently the total acoustic radiation power of cylindrical structure, surface velocity is measured and radiation efficiency of surface element is calculated. Then, they are substituted to the surface pressure in the simplified Helmholtz integral equation which assumes acoustic far-field and plane-wave approximation at the surface. Surface velocity and total acoustic radiation power for a submerged cylinder are measured in water-tank. In this example, it is found that total acoustic power output obtained from the prediction is in good agreement with that of measurement in mid-high frequency range.

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