• Title/Summary/Keyword: Decrease of Surface Temperature

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A measurement of piston surface temperature by using instantaneous temperature measuring probe (순간온도 계측 프로브를 사용한 피스턴 표면 온도측정)

  • 이성열;이영조
    • Journal of the korean Society of Automotive Engineers
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    • v.12 no.6
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    • pp.60-66
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    • 1990
  • In order to measure the piston surface temperature and heat flux, autors have developed the measuring system with an instantaneous temperature probe. Such the instantaneous temperature probes were embodied into the top of piston for measurement and L-link system, designed to fit the test engine, extracts the thermocouple wires from the piston outside of engine employing a mechanical linkage. Then the instantaneous surface temperature was measured to calculate the heat flux flowing into the top surface of piston in a spark ignition engine. As a result, the following phenomena have been obtained through the study. 1) It is found that the time response and durability of temperature probe with a thin film thickness 10um and mechanical linkage with thermocouple wire extraction is sufficient at this experiment. 2) For the quantitative effect of variation in engine speed, the temperature swing and heat flux on the top of piston increase with increasing the engine speed. 3) It is proved that the temperature swing and heat flux decrease with distance from spark plug.

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The Effect of Urban Road Vegetation on a Decrease of Road Surface Temperature (도시도로 녹지의 도로 표면온도 져감 효과에 관한 연구)

  • Cha, Hye-Jin;Lim, Ji-Hyun
    • Journal of the Korean Institute of Landscape Architecture
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    • v.39 no.3
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    • pp.107-116
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    • 2011
  • One of the major factors which increase urban temperature is roads. This paper is aimed to investigate the effect of urban roadside vegetation on the road surface temperature. For this, surface temperature was measured at 18 spots using the thermal imaging camera in terms of road components including use of roadside land use, roadway, sidewalk, roadside vegetation and vegetation median barrier. The size of the roadside vegetation and related urban road characteristics were also measured. In terms of the effect of roadside vegetation on a decrease in road surface temperature, the roadside land use as a green area or open space was the highest, followed by the size of vegetation median barrier and the size of roadside vegetation. Besides road surroundings, an increase in the green zone such as roadside vegetation and median strip vegetation has a significant impact on lowering road surface temperature. Therefore, a good solution for reducing urban heat island effects would be to increase the area of roadside vegetation and green areas along roads.

An Evaluation of the Phenomenon of Heat-Island Effect by Multi-Criteria Methods (다항목 평가기법의 적응을 통한 열섬현상의 평가)

  • Lee Jung-Min;Do Hu-Jo;Ra Jung-Hwa;Kim Soo-Bong;Jung Eung-Ho
    • Journal of Environmental Science International
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    • v.14 no.11
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    • pp.1005-1014
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    • 2005
  • The purpose of this research was to present multi-criteria which were related to the heat island and find methods which decreased heat island affection on the ecological landscape planning. The results of this study were as follows. According to the analysis of surface temperatures, the first grade was the outside-city like a mountain and its temperature was less than $13.0^{\circ}C$. The fifth grade was the downtown, industrial area and its temperature was more than $26.9^{\circ}C$. Therefore, the result was seen the serious heat-island effect. The results of field survey, the closer to the first grade, the higher the value of green coverage. The closer to the fifth grade, the higher the value of impermeability surface, paving materials and colors. According to the correlation analysis, the temperature had high correlation with impermeability surface, paving materials and colors. According to the simple regression analysis, permeability surface, green coverage, topography, impermeability surface, paving materials f: colors, human impact related with surface temperatures. To plan for the decrease of Heat-Island Effect needed the extension of green space, decrease of impermeability surface. This research suggested data for urban green plan and decrease of heat island effect, but there was a limit to get the objective method for grade classification because of lacking in the basic data, the research of multi-criteria will be accomplished continuously.

A Study on the Distribution Characteristic of Urban Surface Temperature and Urban Heat Island Effects (도시 지표면 온도분포 특성 및 열섬완화방안)

  • Do, Hu-Jo;Lee, Jung-Min;Ra, Jung-Hwa
    • Journal of Environmental Science International
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    • v.16 no.5
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    • pp.611-622
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    • 2007
  • The purpose of this research was to three-criteria landuse-pattern, developing density, NDVI which were related to the heat island and find the distribution characteristic of urban surface temperature and urban heat island effects. The results of this study were as follows. According to the analysis of surface temperatures, the first grade was the outside-city like a mountain and its temperature was less than $12.18^{\circ}C$. The fifth grade was the downtown industrial area and its temperature was more than $23.54^{\circ}C$. It means Daegu-Metropolitan-City has the serious heat-island effect. the results of landuse pattern analysis, in case of fifth and forth grade, city area was occupied over 90% with residential, commercial and industrial areas, but in case of third grade, openspace was occupied over 70%. The results of developing density analysis, the temperature had high correlation with building ratio, road ratio, vegetation ratio and etc. To plan for the decrease of heat island effect needed the extension of green space, decrease of paving, but there was a limit to get the objective method for grade classification because of lacking in the basic data, the research of criteria will be accomplished continuously.

A Study on Time-Dependent Optimal Heater Control for Thermoforming Using Response Surface Method (열성형 과정에서 반응면 기법을 이용한 히터의 비정상 최적제어에 관한 연구)

  • Li, Zhen-Zhe;Heo, Kwang-Su;Seol, Seoung-Yun
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2528-2533
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    • 2007
  • Thermoforming is one of the most versatile and economical processes available for the manufacturing polymer products. The drawback of thermoforming is difficult to get uniform thickness of final products. For the distribution of thickness strongly depends on the temperature distribution of sheet, the adjustment of heater power is very important In this paper, an optimization study for getting uniform temperature distribution was carried out using dual optimization steps. At first, the steady state optimal distribution of heater power is searched by numerical optimization to get uniform temperature of sheet surface. In the second step, time-dependent optimal heater inputs have been found out to decrease the temperature difference through the direction of thickness using Rseponse Surface Method and D-optimal method. The optimization results show that the time-dependent optimal heater power distribution gives acceptable uniform sheet temperature in the field of forming temperature..

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Polishing Mechanism of TEOS-CMP with High-temperature Slurry by Surface Analysis

  • Kim, Nam-Hoon;Seo, Yong-Jin;Ko, Pil-Ju;Lee, Woo-Sun
    • Transactions on Electrical and Electronic Materials
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    • v.6 no.4
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    • pp.164-168
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    • 2005
  • Effects of high-temperature slurry were investigated on the chemical mechanical polishing (CMP) performance of tetra-ethyl ortho-silicate (TEOS) film with silica and ceria slurries by the surface analysis of X-ray photoelectron spectroscopy (XPS). The pH showed a slight tendency to decrease with increasing slurry temperature, which means that the hydroxyl $(OH^-)$ groups increased in slurry as the slurry temperature increased and then they diffused into the TEOS film. The surface of TEOS film became hydro-carbonated by the diffused hydroxyl groups. The hydro-carbonated surface of TEOS film could be removed more easily. Consequently, the removal rate of TEOS film improved dramatically with increasing slurry temperature.

Measurement of Kager's Triangle Area and Retrocalcaneal Surface Temperature by shoes heel height (신발 굽 높이에 따른 Kager씨 삼각의 면적과 후종족부의 표면온도 측정)

  • Jeon, Byeongkyou;Yeo, Jindong;Shin, Jungsub
    • Journal of the Korean Society of Radiology
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    • v.6 no.6
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    • pp.521-529
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    • 2012
  • The aim of this study was to analyze radiological change of Kager's triangle area and retrocalcaneal surface temperature by shoes heel height. Area of Kager's triangle was measured by simple radiography study And PACS of INFINITI. Retrocalcaneal surface temperature were measured by DITI. Area of Kager's triangle and retrocalcaneal surface temperature were calculated for comparison and analysis, with flat shoes and high heel shoes. Area of Kager's triangle($0.88cm^2$) and retrocalcaneal surface temperature ($1.4^{\circ}C$)tends to decrease with high heel shoes. The highest and shortest of the Kager's triangle area and a surface temperature difference between flat shoes and high heel shoes, each $0.9cm^2$, $1.2cm^2$, $1.6^{\circ}C$, $0.5^{\circ}C$ and showed slight differences. The highest weight and the lowest weight of a surface area and the temperature difference between flat shoes and high heels, each $1.8cm^2$, $0.8cm^2$, $1.1^{\circ}C$, $0.2^{\circ}C$ and higher weight Kager's area and the surface temperature is decreased. The longest time and shortest time of a surface area and the temperature difference between high heels, each $0.8cm^2$, $1.4^{\circ}C$. In conclusion, Areas of Kager's triangle and retrocalcaneal surface temperature decrease with high heel shoes. If we wear high heel shoes for a long time, retrocalcaneal pain and blood flow disorder will occurs.

EXPERIMENTS ON THE INTERACTION OF WATER SPRAYS WITH POOL FIRES

  • Han, Yong-Shik;Kim, Myung-Bae;Shin, Hyun-Dong
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 1997.11a
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    • pp.518-525
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    • 1997
  • A series of measurements and visualization to investigate the interaction of water sprays with pool fires is presented. Fire source is a small-scale pool burner with methanol, ethanol and gasoline. Measurements of temperatures, $O_2$, $CO_2$, and CO concentrations along the plume centerline are carried out to observe pool fire structures without water sprays. Visualization by the Ar-ion laser sheet shows flow pattern of droplets of the sprays above the pool fires. It is observed that in the case of methanol and ethanol, water sprays continuously penetrate into the center of fuel surfaces. The gasoline pool fire allows intermittent penetration of water sprays because of pulsating characteristics of the gasoline flame. To evaluate the cooling effect of the fuel surface by the sprays, the temperature was measured at the fuel surface. As soon as the mists reach the fuel surface of methanol and ethanol, the temperatures of the fuel surface decrease rapidly below the boiling point, and then the fires are extinguished. Due to the application of mist upon the gasoline fire, though the fuel temperature decrease abruptly at the time of the injection, such a rapid decrease do not continue till the extinction point.

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A study on abrasive wear characteristics of side plate of FRP ship (온도변화에 따른 유리섬유/폴리우레탄 복합재료의 충격파괴거동)

  • Kim, Byung-Tak;Koh, Sung-Wi
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.45 no.3
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    • pp.188-193
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    • 2009
  • The present study was undertaken to evaluate the effect of temperature on the results of Charpy impact test for glass fiber reinforced polyurethane(GF/PUR) composites. The Charpy impact test were conducted in the temperature range from -50$^{\circ}$ to 50$^{\circ}$. The impact fracture toughness of GF/PUR composites was considerably affected by temperature and it was shown that the maximum value was appeared at room temperature. It is believed that sensitivity of notch on impact fracture energy were increased with decrease in temperature of specimen. As the GF/PUR composites exposed in low temperature, impact fracture toughness of composites decreased gradually owing to the decrease of interface bonding strength caused by difference of thermal expansion coefficient between the glass fiber/polyurethane resin. And decrease of interface bonding strength of composites with decrease in specimen temperature was ascertained by SEM photographs of Charpy impact fracture surface.

Application of High Resolution Land Use Data on the Possibility to Mitigate Urban Thermal Environment (고해상도 지표자료를 이용한 도시 열환경 완화효과 가능성에 관한 연구)

  • Lee, Kwi-Ok;Lee, Hyun-Ju;Lee, Hwa-Woon
    • Journal of Environmental Science International
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    • v.18 no.4
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    • pp.423-434
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    • 2009
  • In recent years, the urban thermal environment has become worse, such as days on which the temperature goes above $30^{\circ}C$, sultry nights and heat stroke increase, due to the changes in terrestrial cover such as concrete and asphalt and increased anthropogenic heat emission accompanied by artificial structure. The land use type is an important determinant to near-surface air temperature. Due to these reasons we need to understand and improve the urban thermal environment. In this study, the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model(MMS) was applied to the metropolitan of Daegu area in order to investigate the influence of land cover changes and urban modifications increase of Albedo to the surface energy budget on the simulated near-surface air temperature and wind speed. The single urban category in existing 24-category U.S. Geological survey land cover classification used in MM5 was divided into 6 classes to account for heterogeneity of urban land cover. As a result of the numerical simulation intended for the metropolitan of Daegu assumed the increase of Albedo of roofs, buildings, or roads, the increase of Albedo (Cool scenario)can make decrease radiation effect of surface, so that it caused drops in ambient air temperature from 0.2 to 0.3 on the average during the daylight hours and smaller (or near-zero) decrease during the night. The Sensible heat flux and Wind velocity is decreased. Modeling studies suggest that increased surface albedo in urban area can reduce surface and air temperatures near the ground and affect related meteorological parameters such as winds, surface air temperature and sensible heat flux.