• Title/Summary/Keyword: surface pressure measurement

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

  • 이재순;김기태;이현구;강태경;우종헌;김수성
    • Transactions of the Korean Society of Automotive Engineers
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    • v.5 no.5
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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
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.02a
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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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    • v.4 no.5
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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.

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

  • Yang, Dae-Jung
    • Korean Journal of Applied Biomechanics
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    • v.22 no.2
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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
    • Proceedings of the International Microelectronics And Packaging Society Conference
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    • 2004.11a
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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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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 (압력면익단소익이 터빈 동익 압력면스퀼러팁 하류의 팁누설유동 및 압력손실에 미치는 영향)

  • Cheon, Joo Hong;Lee, Sang Woo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.40 no.10
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    • pp.645-651
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    • 2016
  • Effects of pressure-side winglet width on the tip leakage flow and aerodynamic loss downstream of a turbine blade with a pressure-side squealer rim have been investigated for the tip gap-to-span ratio of h/s = 1.36%. The pressure-side squealer has a fixed height-to-span ratio of $h_p/s=3.75%$ and the pressure-side winglet, which is installed at an elevation of tip surface, has width-to-pitch ratios of w/p = 2.64%, 5.28%, 7.92% and 10.55%. The results show that with increasing w/p, aerodynamic loss in the passage vortex region decreases, whereas that in the leakage flow region increases. As a result, the mass-averaged loss coefficient all over the measurement plane tends to decrease minutely with the increment of w/p. It is concluded that the pressure-side winglet for the pressure-side squealer tip can hardly contribute to the tip-leakge loss reduction.

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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    • v.21 no.4
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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.

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

  • Jeon, Young-Jin;Kim, Ki-Su;Seo, Hyung-Seok;Byun, Yung-Hwan;Lee, Jae-Woo
    • Journal of the Korean Society of Propulsion Engineers
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    • v.12 no.1
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    • pp.7-15
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    • 2008
  • Pressure Sensitive Paint(PSP) means a reacting paint in pressure. The calibration of PSP and the wind tunnel test of PSP painted model are required to measure pressure by using PSP. Therefore, the post processing from these results shows the information and image of the pressure distribution. PSP can show the information of total pressure from the wind tunnel test and the calibration. In this study, equipments of PSP are composed, and experiment is accomplished by using PSP. The surface pressure distribution around the wall of nozzle is measured by PSP. The measured pressure has similar results to those of the CFD and pressure tap measurement.

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

  • Paik, Bu-Geun;Kim, Kyung-Youl;Ahn, Jong-Woo;Kim, Yong-Soo;Kim, Sung-Pyo;Park, Je-Jun
    • Journal of the Society of Naval Architects of Korea
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    • v.43 no.4 s.148
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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.

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

  • Han, Seungjin;Lee, Jongju;Kang, Myunghwan;Bae, Sooryong;Jung, Woojin
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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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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