• Journal of Advanced Marine Engineering and Technology
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• v.22 no.2
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• pp.190-199
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• 1998

a new measuring method is suggested to determine the time constant of a thermocouple wire to be applied for the measurement of the true fluid temperatures in varying flow states. Based on the techniques of internal heating which are commonly used to measure mean time constants we extend the existing method to measure instantaneous time constants continuously. A method of measurement and analysis is presented and verified experimentally.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1995.05a
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• pp.120-123
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• 1995

Maxwell-Displacement-Currnt-Measuring Technique(MDCM) is a simple system for displacement current measuring which consist with two electrodes to the electrometer, With this method, the displacement current flow only when the electric flux density change by the displacement of molecules or charge particles of membrance on the water surface. Thus, It is Possible to detect dynamic behavior of molecules of membrane without any electrical contact with molecule membrane. In this paper, We measure surface pressure, displacement current and dipole moment of phospholipid monolayers on the wafer surface with applied pressure by MDCM and We measured DTA(differential thermal analysis).

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.15 no.1
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• pp.9-18
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• 2003

An experimental study was performed to investigate the turbulence intermittency measuring methods across the boundary layer in the transition region. A single type hot-wire probe was used to measure instantaneous streamwise velocities in laminar, transitional and turbulent boundary layer To estimate wall shear stresses on the flat plate, near wall mean velocities are applied to the principle of CPM. Distribution of intermittency factor is obtained by dual-slope method and compared to the results of four methods,$\'{u},\;\{U}$, TERA and M-TERA method. In these methods, M-TERA shows a good agreement in the near wall region. However, the result of M-TERA method shows that intermittency factor is underestimated in the outer part and outside of the boundary layer and the dimensional constant of M-TERA method should be changed appropriately depending on measuring point.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.4
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• pp.219-227
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• 2014

Natural disasters such as a ground collapse and a landslide have broken out due to the climate change of the Korea and the reckless expansion of cities and roads. The climate changes and the reckless urbanization have made the ground weak. Thus, it is important to keep a close eye on the highly weakened landslide and to prevent its natural disasters. In order to prevent these disasters, this paper presents a system of recognizing the road slide condition by measuring the displacements using laser scanner instrument. The previous system of monitoring the road slide has some problems as inaccurate recognition due to using only images from a camera, or expensive system such as artificial satellites and aircraft systems. To solve this problem, our proposed system uses the 3D range data from the laser scanner for measuring the accurate displacement of the road slide and optical flows from the Lucas-Kanade algorithm for recognizing the road slide in the image.

• Journal of Forest and Environmental Science
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• v.28 no.1
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• pp.1-7
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• 2012

Tropical forests whether fragmented or undisturbed or be they equatorial or deciduous, remain the storehouse of biodiversity for hundreds of thousands of plant and animal species. This unique characteristic continues to attract a wide range of scientists and international organizations to study and attempt to understand tropical forest ecosystems. Gene flow is mediated by pollen, seed and seedling dispersal, and factors affecting this gene flow include phenology, spatial distribution, population structures, seed predation, sexual and mating systems as well as physical and biological barriers to gene flow. Two methods are used in measuring gene flow: direct method that relies on the actual observation of seed and pollen dispersal, whereas indirect methods involve the use of genetic markers such as allozymes and DNA techniques. Political strife, extreme natural and artificial disasters, the lack of a comprehensive forestry research vision, coupled with difficult socio-economic conditions in Africa have made the environment quite difficult for sustained research activities on the part of those undertaking or wishing to undertake such studies. Gene flow studies in this region are few and far between. This review elaborates on the mechanisms of gene flow mediation in Sub-Saharan Africa.

• Proceedings of the KSME Conference
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• 2001.06e
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• pp.727-732
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• 2001

The purpose of this study is to compare the time mean velocity distribution, the time mean kinetic energy, and the time mean turbulence intensity between vertical and horizontal flow fields in a coaxial circular pipe by PIV measurement. Experiments are performed at a Reynolds number 2,000, measuring regions divided as the section regions A, B, C, D in flow fields. The angle of the high-frequency ultrasonic is selected in the direction of $45^{\circ}$ to the flow axes and it is reflected several times. In results, it is clarified that the effect of gravity is given in the vertical flow field compared with the horizontal flow field and the ultrasonic affects the turbulence enhancement. And kinetic energy and turbulence intensity with ultrasonic are shown slightly bigger than those in flow field without it.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.1
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• pp.59-65
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• 2004

The configuration of intake port and piston is a dominant factor of inlet air flow and mixture formation in an engine cylinder, resepectively. This study has analyzed intake port and piston characteristics for swirl flow of a heavy-duty LPG engine. As an available technology to optimize intake port, the steady flow rig test has been applied for measuring swirl ratio and mean flow coefficient. And we measured the mean velocity and turbulence intensity of swirl flow under motoring condition in transparent engine cylinder by backward scattering LDV system. From these results, the piston and cylinder head with a good evaluated swirl flow characteristics were developed and adapted fur a 11L heavy-duty engine using the liquid phase LPG injection (LPLI) system. The obtained results are expected to be a fundamental data for developing intake port and piston.

• Journal of Sensor Science and Technology
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• v.1 no.1
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• pp.35-41
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• 1992

A constant temperature type of flow sensor using a solid state micromachining technology was developed for measuring the velocity of gas or liquid. It was designed to detect only the heat convection related to flow velocity. Other heat transfer terms and common mode interferences are canceled by differentiating both reference and exposed flow sensor. It employs the principle that the change of current through the sensing element can be used to measure the flow velocity. An experimental study of the behavior on this flow sensor was performed in a narrow tube(diameter : 8mm) for city water. The relation between power consumption of the flow sensor and square-root of flow velocity is almost linear in the low velocity range(0-200 cm/sec).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.4
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• pp.1472-1480
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• 1996

The phenomena of drag reduction using small quantities of a linear macromolecules has attracted the attention of experimental investigations. It is well known that drag reduction in single phase liquid flow is affected by polymer materials, molecular weight, polymer concentration, pipe diameter and flow velocity. But the research on drag reduction in two phase flow has not intensively investigated. Drag reduction can be applied to phase change system such as chemical reactor, pool and boiling flow, and to flow with cavitation which occurs pump impellers. The purpose of the present work is to evaluate the drag reduction by measuring pressure drop, mean liquid velocity, and turbulent intensity and determine the effects of polymer additives on drag reduction in horizontal two phase flow. Experimental results show higher drag reduction using co-polymer comparing with using polyacrylamide. Mean liquid velocities increase as adding more polymer, and turbulent intensities decrease as the distance for the wall in inversed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.3
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• pp.590-595
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• 2008

A new adaptive TMS variable area flow meter that is used to the environment measuring equipment is proposed. This system is consist of a ball moving within the tube line which corresponds to gas flow and photo sensor array which monitoring the movement of ball. This system can monitoring the position of bali in case of the very few gas flow in various levels. And it can automatically adjust the gas flow at the highest and the lowest level to prevent the tube line blockage.