• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.465-470
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• 2002

For measuring friction-factor of artificially-roughened surfaces which are usually applied on damper seals, flat plate test apparatus is designed and fabricated. the measurement of leakage and pressure distribution through round-hole pattern specimen with different hole area is described and a method is discussed for determining the friction-factor experimentally. Results show that the friction-factor of the round-hole pattern surfaces is bigger than that of smooth surface and increases as increasing the hole area. A empirical friction factor model for round-hole pattern surface is defined as the Moody's friction factor formula.

• 자원환경지질
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• 제20권3호
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• pp.159-168
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• 1987

Some physico-chemical properties such as surface area, moisture content, cation exchange capacity, swelling rate, pH, viscosity and liquid limit have been determined for evaluation of Cabentonite deposit occurring in four localities; Yonil, Gampo, Haseo and Pohang, in Gyeongsang-do. Montmorillonite contents can be derived from surface area measurement. Enhancement of liquid limit values and swelling volume were observed in the samples which had higher exchangeable Na ion and finer particle-size distribution. Identical results were observed even in the Na-exchanged samples. This suggests that aggregation effects have a great influence on physico-chemical properties. Aggregation of montmorillonite were controlled not only burial depth but also composition of exchangeable cation. Consequently, sample occurred in Yonil area where has the greatest burial depth in the area show somewhat lower physico-chemical properties than those of samples occurred in the other localities. However, the basic test applied in this study provides very useful preliminary information relating to its commercial potential.

• 한국방사선학회논문지
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• 제6권6호
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• pp.521-529
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• 2012

본 연구의 목표는 신발 굽 높이에 따른 Kager씨 삼각 면적의 방사선영상 변화와 후종족부의 표면온도 변화를 알아보고자 연구하였다. 카이거씨 면적은 단순 방사선촬영검사와 인피니티 영상저장전송시스템을 이용하여 측정 하였다. 후종족부의 표면온도는 전산화적외선체열검사를 이용하여 측정하였다. 운동화 착용 대상자에게 신발 굽 높이가 다른 하이힐을 착용시켜 카이거씨 삼각 면적과 후종족부의 표면온도 차이를 분석 하였다. 하이힐 대상자들은 운동화 대상자들에 비하여 카이거씨 삼각 면적이 $0.88cm^2$, 후종족부의 표면온도가 $1.4^{\circ}C$ 각각 감소하였다. 최고신장과 최저신장의 카이거씨 면적과 표면온도의 차이는 운동화와 하이힐에서 각각 $0.9cm^2$, $1.2cm^2$, $1.6^{\circ}C$, $0.5^{\circ}C$이며 모두 미세한 차이를 나타냈다. 최고체중과 최저체중의 카이거씨 면적과 표면온도의 차이는 운동화와 하이힐에서 각각 $1.8cm^2$, $0.8cm^2$, $1.1^{\circ}C$, $0.2^{\circ}C$이며 체중이 높을수록 카이거씨 면적과 표면온도가 감소하였다. 하이힐 최장시간 착용자와 최저시간 착용자의 카이거씨 면적과 표면온도의 차이는 각각 $0.8cm^2$, $1.4^{\circ}C$, 이며 착용시간이 증가함에 따라 카이거씨 면적과 표면온도가 감소하였다. 결론적으로 하이힐을 장시간 착용하면 후종족부 통증과 혈류 장애를 유발 할 것으로 고려된다.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2007년도 추계학술대회
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• pp.149-154
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• 2007

This study examines the effect of acoustic excitation using forced coaxial air on the flame characteristics of turbulent hydrogen nonpremixed flames. A resonance frequency was selected to acoustically excite the coaxial air jet due to its ability to effectively amplify the acoustic amplitude and reduce flame length and NOx emissions. Acoustic excitation causes the flame length to decrease by 15 % and consequently, a 25 % reduction in EINOx is achieved, compared to a flame without acoustic excitation. Moreover, acoustic excitation induces periodical fluctuation of the coaxial air velocity, thus resulting in slight fluctuation of the fuel velocity. From phase-lock PIV and OH PLIF measurement, the local flow properties at the flame surface were investigated under acoustic forcing. During flame-vortex interaction in the near field region, the entrainment velocity and the flame surface area increased locally near the vortex. This increase in flame surface area and entrainment velocity is believed to be a crucial factor in reducing flame length and NOx emission in coaxial jet flames with acoustic excitation. Local flame extinction occurred frequently when subjected to an excessive strain rate, indicating that intense mass transfer of fuel and air occurs radially inward at the flame surface.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.567-569
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• 2006

Recently, the terrestrial laser scanner is considered as useful measurement equipment for acquiring a three-dimensional data. In this study, a terrestrial laser scanner which has +/- 2.5cm accuracy is examined whether the terrestrial laser scanner is reliable to present the tendency of landslide movement. The test area is covered by protection blocks, and they are being moved by landslide movement. Landslide movement was detected by measuring the movement of protection blocks. Totally three scenes of test area were acquired during 2004 and 2006. The three scenes of the protection blocks were registered in global coordinate system, then the landslide movement was investigated. The landslide movement detected in the three scenes was evaluated by comparing with landslide movement measured by a total station. Although the measurement accuracy of landslide using the terrestrial laser scanner was worse than the total station, the scanning data showed the tendency of landslide movement of the test area.

• 한국생활과학회지
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• 제19권6호
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• pp.1045-1052
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• 2010

Effects of the ease of pattern on the thermal conditions of clothing were investigated through the measurement of clothing surface temperatures using infrared thermography. Four vests with different pattern ease were worn by five male subjects. Surface temperature distribution on the clothing were then examined using a thermogram to view thermo-regulating characteristics affected by the ease of pattern. Representative surface temperatures were calculated based on the percentage of the surface area within a certain temperature range and the midpoint value of the corresponding area. Representative surface temperatures matches well to the thermal insulation value measured by thermal manikin. Results indicated that representative surface temperature could be a useful quantitative value if some simple calculations were to be used alongside accurate image processing.

• 한국정밀공학회지
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• 제21권6호
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• pp.94-101
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• 2004

From the Beckmann's reflection model of wave incident, reflected light from a surface is known to have not only specular but also diffuse components. The specular component dominant a surface for a mirror-like surface is distributed on the almost the same area as the spot on the surface, but the diffuse component region dominant f3r a rough surface spreads scattered on the larger areas than the spot. Therefore, statistic parameters from the scattered light distribution are more meaningful in the diffuse region, while the magnitude of rather meaning in the specular region. In usual, there need two sensors to acquire two kinds of information: Photo-detector for light intensity magnitude and image sensor for light intensity distribution. But dual sensor scheme requires a beam splitter usually to feed light to each sensor, and moreover there is not a combination rule to relieve the different sensor characteristics. In this study a new method is proposed for acquisition of the dual information using only an image sensor. Specular region is established on an image area being distinguished from a diffuse component, and laser power is adjusted so that no pixel of the image sensor in the specular region is saturated. Simulation based on the light reflection theory and the experimental results are quite well matched, and thus the proposed method was proved to be very useful for mirror-like surface measurement.

• 한국산업보건학회지
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• 제20권3호
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• pp.203-215
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• 2010

This study is an overview of toxicities and measurement techniques of ultrafine particles (UFPs), and their exposure controls. UFPs are ubiquitous in many working situations. Exposure to UFPs is possibly causing adverse health symptoms including cardio-respiratory disease to humans. In order to measure exposure levels of airborne UFPs, there are current available measurement guidelines, instruments and other techniques (i.e. contour mapping, control banding). However, these risk assessment techniques including measurement techniques, controls and guidelines are dependent on background levels, metrics (e.g. size, mass, number, surface area, composition), environmental conditions and controls. There are no standardized measurement methods available and no generic and specific occupational exposure standards for UFPs. It is thought that there needs to be more effort to develop Regulations and Exposure Standards for generic UFPs should be based on more exposure data, health surveys, toxicological data and epidemiological data. A carefully considered hierarchy of controls can also reduce the maximum amount of airborne UFPs being emitted from diverse sources in industries.

• 한국초전도ㆍ저온공학회논문지
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• 제15권2호
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• pp.48-51
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• 2013

The thermal contact resistance (TCR) is one of the important components in the cryogenic systems. Especially, cryogenic measurement devices using a cryocooler can be affected by TCR because the systems have to consist of several metal components in contact with each other for heat transferring to the specimen without cryogen. Therefore, accurate measurement and understanding of TCR is necessary for the design of cryogenic measurement device using a cryocooler. The TCR occurs at the interface between metals and it can be affected by variable factors, such as roughness of metal surface, contact area and contact pressure. In this study, we designed TCR measurement system at various temperatures using a cryocooler as a heat sink and used steady state method to measure the TCR between metals. The copper is selected as a specimen in the experiment because it is widely used as a heat transfer medium in the cryogenic measurement devices. The TCR between Cu and Cu is measured for various temperatures and contact pressures. The effect of the interfacial materials on the TCR is also investigated.

• 한국태양에너지학회 논문집
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• 제29권5호
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• pp.88-97
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• 2009

In these days, it attracts our attention to create a green outdoor environment around the building block in urban area. Green space and permeable ground covering are increased by laws and regulations. According to these trends, variety researches for improving outdoor environment are accomplished at this moment. However, the problems for outdoor environment such as heat island effect and air contaminant in urban area are still reported. The purpose of this study is to examine the variables to affect the formation of outdoor thermal environment by quantitative analysis. As a initial study, in this paper, the effect of ground composition on changes of surface temperature and heat flux in multi-residential building were analyzed by field measurement and numerical simulation. Through field measurement, the surface temperature and heat flux of artificial ground in multi-residential building in Suwon city were measured. The result showed that the surface temperature was decreased by about $20^{\circ}C$ with afforestation of artificial ground compared with those of concrete covering. Moreover, the inner temperature of artificial ground was changed as same behaviors of outdoor temperature changes to depths of 20cm. In simulation, the effect of soil types and depth of artificial ground on the changes of the surface temperature and heat flux were analyzed. As results, the natural soil ground was more effective against lowering the surface temperature than any other cases in the analyzed cases.