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        검색결과 305

        261.
        2021.10 KCI 등재 서비스 종료(열람 제한)
        The relationship between night cooling rate and meteorological elements was investigated over the past five years (2016-2020), using weather data from the new (Daegu(143)) and old (Shinam(860)) Daegu Regional Meteorological Agency located in the suburban and urban regions, respectively. There was a correlation between the total daily amount of solar radiation (Stot) and the night cooling rate in the both regions. However, a higher correlation was observed at the new Daegu Regional Meteorological Agency station (Daegu(143)). In particular, data from the new Daegu Regional Meteorological Administration's observatory, which experiences a low thermal storage effect caused by artificial structures, showed a higher correlation between nighttime cooling and weather factors. The reason for this is that the lesser the heat storage effect caused by the artificial structures, the better the effect of surface radiation cooling on temperature reduction. These findings confirm that the correlation between night cooling and weather factors can be used to assess the impact of artificial structures in cities.
        262.
        2020.06 KCI 등재 서비스 종료(열람 제한)
        According to a NASA Goddard Institute for Space Studies report, temperatures have risen by approximately 1 °C so far, based on temperatures recorded in 1880. The 2003 heatwave in Europe affected approximately 35,000 people across Europe. In this study, a cooling fog, which is used in smart cities, was designed to efficiently reduce the temperature during a heatwave and its pilot test results were interpreted. A model experiment of the cooling fog was conducted using a chamber, in which nano mist spray instruments and spray nozzles were installed. The designed cooling fog chamber model showed a temperature reduction of up to 13.8 °C for artificial pavement and up to 8.0 °C for green surfaces. However, this model was limited by constant wind speed in the experiment. Moreover, if the cooling fog is used when the wind speed is more than 3m/s in the active green zone, the temperature reduction felt by humans is expected to be even greater. As a second study, the effect of cooling fog on temperature reduction was analyzed by installing a pilot test inside the Land Housing Institute (LHI). The data gathered in this research can be useful for the study of heat reduction techniques in urban areas.
        263.
        2019.04 KCI 등재 서비스 종료(열람 제한)
        본 연구의 목적은 레이노 현상 의심 환자의 정량적 판독 보조 지표의 가능성을 확인하고자 하는 것이다. 레이노 현상 의심 환자 99명에서 가능성 낮음 48명, 중간 16명, 높음 35명을 대상으로 하였다. 검사는 15.2± 0.8°C 얼음물에 10분 간 양 손을 한랭 부하 후 99mTc 370 MBq(10 mCi)를 정맥 주사하였다. 이 후 5분, 10분, 20분 양측 열 손가락의 온도 변화를 측정하였고, 핵의학 판독의의 판독 결과와 온도 변화를 비교하였다. 판독 결과 레이노 현상의 가능성이 낮은 군은 손가락 온도가 32.6±4.9°C로 높게 측정되었고, 가능성이 높은 군은 22.7±6.0°C로 낮게 측정되었다(p<0.05). 결론적으로 레이노 현상 의심 증상에 따라 손가락 온도의 차이가 났음을 확인하였고 이를 통해 손가락 온도의 측정이 레이노 진단의 정량적 보조 지표로서의 가능성이 있음을 확인하였다.
        264.
        2018.12 KCI 등재 서비스 종료(열람 제한)
        The purpose of this study was to investigate changes in the external thermal environment, following the application of evaporative cooling systems in buildings, in response to climate change. In order to verify changes in the external thermal environment, a T-test was performed on the microclimate, Thermal Comfort Index (TCI), and building surface temperature. Differences in microclimate, following the application of the evaporative cooling system in the building, were significant in terms of temperature and relative humidity. In particular, temperature decreased by more than 7% when the evaporative cooling system was applied. According to the results of the Thermal Comfort Index analysis, the Wet-Bulb Globe Temperature (WBGT) was below the limit of outdoor activities, indicating that outdoor activities were possible. The Universal Thermal Climate Index (UTCI) values were within the very strong heat stress range when the evaporative cooling system was not applied, When the system was applied, the UTCI values were within the strong heat stress range, indicating that they were lowered by one level. The building surface temperature decreased by ~10% or more when the evaporative cooling system was applied, compared to when it was not applied. Finally, the outside surface temperature of the building decreased by ~12% or more when the system was applied, compared to when it was not applied. We conclude that the energy saving effect of the building was significant.
        265.
        2018.08 KCI 등재 서비스 종료(열람 제한)
        A Cultivation method to minimize the damage caused by high temperatures was studied by investigating the effects of groundwater cooling treatment on the growth, yield, and quality of strawberries. In the groundwater cooling treatment, the daily average temperature of the rhizosphere was reduced from 26.9°C to 24.9°C . The root length increased by 0.3–9.2 cm, depending on the cultivar and growth period. The leaf number, leaf area, leaf length, leaf diameter, and plant height also increased, especially in the cultivars ‘Seolhyang’ and ‘Maehyang’, resulting in higher fresh and dry weights. The number of fruit per plant increased from 7.7 to 12.5 in ‘Seolhyang’, and the fruit weight increased by 0.3 g in ‘Seolhyang’ and 1.3 g in ‘Maehyang’. The fruit hardness increased, but no significant difference in fruit coloration was observed. The sugar content of the fruit was improved by 0.2–0.3 °Brix. Therefore, groundwater cooling of the rhizosphere was effective in improving the growth and productivity of strawberries under abnormally high temperature conditions and can be considered a cost-efficient cooling system.
        266.
        2017.09 서비스 종료(열람 제한)
        As the Photovoltaic system market increases, various technologies are emerging to improve system operation efficiency. Such additional systems of the power generation system are generally referred to as ‘Balance of System’, for example a panel cooling, a panel cleaning and a panel angle adjusting apparatus. In this paper, we discuss an algorithm to calculate the target temperature of cooling in response to changes in the installation environment conditions of the power generation system so that the efficiency improvement rate target set by the user can be achieved with respect to the control method of the cooling water injection system among various panel cooling apparatuses. In order to calculate the target temperature of cooling, the output enhancement coefficient is calculated experimentally based on the temperature change according to the solar radiation condition of the PV panel, and the required reduction temperature of each irradiation condition is calculated considering the efficiency improvement rate. In addition, the efficiency improvement ratio is calculated considering the installation condition of the general power generation system without a separate control group. The thermal performance coefficient of the PV panel test body for calculating the expected temperature of the PV panel is calculated experimentally. The target temperature of cooling is calculated as the sum of the expected temperature of the PV panel and the required reduction temperature, and the injection system that tracks the target temperature by cooling water injection is constructed and compared with the power generation improvement rate and the user setting efficiency improvement rate.
        267.
        2017.06 서비스 종료(열람 제한)
        Research to reduce urban temperatures and mitigate the Urban Heat Island (UHI) effect has focused primarily on the role of large urban green spaces as cool islands (Oke, 2004;Park et al., 2017). However, the role of small green spaces (SGs) such as street trees and pocket parks has not been fully investigated. The purpose of this research is to assess the mitigating effect of SGs on micro-UHI through a comparative analysis of air temperatures of SGs and non-green spaces (NGs), that include building-shaded spaces (BS) and non-shaded, impervious, paved spaces (PS) completely exposed to sunlight. Six urban blocks were the study site and in a highly developed area, Jongnogu and Junggu, Seoul, 37°34′N 126°58′E, South Korea and also located in the same micro-climatic zone. They had SGs which were vegetation patches presented as distinct areas of tree cover. And they were mapped through aerial images analysis and field survey. The experiment was conducted across six urban blocks in a highly developed area in Seoul, South Korea during daytime in summer. Two researchers at each block simultaneously recorded air temperatures at 1.5 m above the ground level using mobile loggers at one-minute intervals for an hour. Measurements were repeated three times, and 1,296 temperature readings were collected in total and made 174 mean temperature data. ArcGIS was used to perform solar radiation analysis to highlight SGs, BSs, and PSs on a thermal map. The highest air temperatures and the lowest air temperatures of each block were extracted and classified. ANOVA and Kruskal-Wallis H test utilizing SPSS statistics were used to verify the significant differences in mean air temperatures between SGs (TSG), PSs (TPS), and BSs (TBS). As a result, ΔTPS-B (the thermal effect of PSs on a block‘s air temperature) ranged from –1.38 ℃ to 2.28 ℃ with fifty-six points, ΔTBS-B (the thermal effect of BSs on a block’s air temperature) ranged from –2.38 ℃ to 2.38 ℃ with fifty-eight points and ΔTSG-B (the thermal effect of SGs on a block’s air temperature) ranged from –1.98 ℃ to 1.62 ℃ with sixty points. 68% (N = 41) of SGs were a negative number of ΔTSG-B while 50% of BSs shows a negative number. The result means that SGs contribute to reducing microscopic UHI than BSs which have much more shade area than SGs have. The results showed that SGs contributed to significantly reducing TBi up to 2.9 ℃ while BS reduced TBi up to 2.7 ℃. The highest TBi was on a PS. The air temperature difference between SGs and NGs over all the blocks ranged from 0.9 ℃ to 2.9 ℃. The air temperature difference between PS and SG was significant and ranged from 0.2 ℃ to 2.0 ℃, while the difference between BS and SG was significant and ranged from 0.1 ℃ to 1.2 ℃.
        268.
        2017.02 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        본 연구에서는 열전소자와 플라즈마 장치를 삽입하여 제작된 컨테이너와 기존의 사용되고 있는 스티로폼(EPS)박스에 소고기를 저장하면서 저장 중 품질특성을 조사하였다. 온도변화 측정 결과 저장기간 동안 TCS-1 컨테이너가 2℃ 이하로 온도유지가 잘 되는 것으로 측정되었다. EPS박스는 저장 3일 이후 소고기가 부패되어 더 이상 실험이 불가능 하였다. 소고기의 신선도를 나타내는 휘발성염기질소(VBN)과 지방산패도(TBA)값의 측정 결과, 저장 7일째 TCS-1의 VBN은 7.72 mg%, TBA는 0.52 mgMA/kg, TCS-2의 VBN 값은 9.20 mg%, TBA는 0.91 mgMA/kg로 측정되어 TCS-1이 TCS-2 보다 유의적으로 적은 증가율을 나타내어 소고기의 신선도를 더 잘 유지하는 것으로 판단되었다. 미생물 변화는 저장 7일 TCS-1은 4.62 log CFU/g, TCS-2는 7.09 log CFU/g으로 측정되어 TCS-1이 유의적으로 미생물 증식 억제에 효과적인 것으로 나타났다. 기호도 조사 또한 저장 7일째 TEU-1은 모든 항목에서 6.5점 이상의 평가를 받았으나 TCS-2는 4.1 이하의 평가를 받아 소고기의 상품성이 상실된 것으로 판단되었다. 모든 분석항목에서 TCS-1이 TCS-2보다 소고기 신선도 유지에 효과적인 것으로 판단되었다.
        269.
        2016.11 KCI 등재 서비스 종료(열람 제한)
        To analyze the cooling effect of urban green areas, we conducted micrometeorological measurements in these areas and their surroundings in Seoul, Korea. From the average hourly temperature measurements through each month for the last two years (March 2013 to February 2015), we found that the maximum temperature difference between urban and green areas was about 2.9℃ at 16:00 LST in summer, and the minimum was about 1.7℃ at 22:00 LST in winter. In summer, the temperature difference was the largest during the day, rather than at night, due mainly to shading by the tree canopy. The specific humidity difference between the two areas was about 1.5 g kg-1 in summer, and this decreased in the winter. The specific humidity difference between urban and green areas in summer is relatively large during the day, due to the higher evapotranspiration level of biologically active plants.
        270.
        2016.09 KCI 등재 서비스 종료(열람 제한)
        This study evaporative cooling system a heat wave climate change and reduction of the inside and outside thermal environment change research. Measurement items included micro meteorological phenomena and measured comfort indices. A micro meteorograph of temperature, relative humidity, surface temperature, and the comfort indices of WBGT, UTCI, and PMV were measured. The difference in inside and outside temperatures were compared for different land types, with the largest difference found in Type A (4.81℃), followed by Type B (4.40℃ ) and Type C (3.12℃). Relative humidity was about 10.43% higher inside due to water injection by the evaporative cooling system. Surface temperature was inside about 6.60℃ higher than the outside all types. WBGT were Type A (3.50℃) > Type B (2.71℃) > Type C (1.88℃). UTCI was low heat stress inside than outside all types. PMV was analysed Type C for inside predicted percentage of dissatisfied 75%, other types was percentage of dissatisfied 100% by inside and outside. Correlation analysis between land cover type and temperature, surface temperature, pmv, utci. T-test analysed inside and outside temperature difference was significant in all types of land.
        271.
        2015.10 서비스 종료(열람 제한)
        This paper was examined the durability properties of concrete using rapid cooling slag as fine aggregate for concrete. The results of experiments, concrete using rapid cooling slag showed that durability properties was equal to concrete using normal fine aggregate.
        272.
        2015.04 서비스 종료(열람 제한)
        This paper was examined the mechanical properties of concrete using rapid cooling slag as fine aggregate for concrete. The results of experiments, concrete using rapid cooling slag showed that mechanical properties was equal to concrete using normal fine aggregate.
        274.
        2014.10 서비스 종료(열람 제한)
        Vertical pipe cooling method was developed for the thermal cracking control of vertically long and slender mass concrete member. This method was applied to mass concrete wall, and the performance of this method was investigated.
        276.
        2014.03 KCI 등재 서비스 종료(열람 제한)
        The geographical distributions of CDDs and HDDs in South Korea for the period 2000~2009 with 2050~2059 are studied by using daily mean temperature data with 1 km horizontal resolution estimated by MK (Modified Korean)-PRISM (Parameter-elevation Regressions an Independent Slopes\ Model) driven by the IPCC (Intergovernmental Panel on Climate Change) RCP (Representative Concentration Pathways)2.6/8.5. The HDD amounts in winter season decrease, declining from north to south and from the high mountain area to the coastal area. In summer season, the higher fuel consumption appears in urban areas, with much higher CDD amounts and for a longer period of time. In the mid-century under RCP2.6 (RCP8.5), HDDs are projected to decrease by 13% (16%) while CDDs are likely to increase by 36% (51%). The total length of cooling (heating) period in Korea is projected to increase (decrease) due to the advance (delay) of the beginning date and the delay (advance) of the end date. These results suggest that special attention should be paid to space cooling, since the cooling demand is expected to grow rapidly in most regions except for mountainous areas. The projection of future CDDs and HDDs will be useful for various energy projects and other environmental applications.
        277.
        2013.06 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The capacity of a pressure fan can be designed based on the air flow resistance of containers packed with fruits and vegetables in a pressure cooling system. This study was conducted to develop an air flow resistance model that was dependent on changes in the air flow rate and the method of stacking containers. The air flow resistance of a container packed with uniformly shaped balls was 1.5 times greater than the sum of the air flow resistance of a vacant container and that of a wire net container packed with only balls. In addition, the air flow resistance increased exponentially as the width of the stacks increased; however, the air flow resistance did not increase greatly as the length and height of the stacks increased, which indicates that the air flow resistance is primarily influenced by the width of the stack in the air flow direction. The air flow resistance in two lines of stacking was up to 17% less than that of the width of the stack. It was also possible to determine the air flow resistance using a function of the air flow resistance through a single container and develop a prediction model. A prediction model of air flow resistance that is dependent on the stacking method and the air flow resistance of a single container was developed.
        278.
        2012.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        We conducted thermal analyses and cooling tests of the space observation camera (SOC) of the multi-purpose infrared imaging system (MIRIS) to verify passive cooling. The thermal analyses were conducted with NX 7.0 TMG for two cases of attitude of the MIRIS: for the worst hot case and normal case. Through the thermal analyses of the flight model, it was found that even in the worst case the telescope could be cooled to less than 206°K. This is similar to the results of the passive cooling test (~200.2°K). For the normal attitude case of the analysis, on the other hand, the SOC telescope was cooled to about 160°K in 10 days. Based on the results of these analyses and the test, it was determined that the telescope of the MIRIS SOC could be successfully cooled to below 200°K with passive cooling. The SOC is, therefore, expected to have optimal performance under cooled conditions in orbit.
        279.
        2012.05 서비스 종료(열람 제한)
        The shell of form-finding is most important in design procedure of the cooling tower, because the shape of the shell determines the sensitivity of dynamic behavior of the whole tower against wind excitation. The purpose of the study is the investigation of the influences of the geometric parameters of the cooling tower shell on the structural behavior. As a result, a hyperbolic rotational shell with the small radius overall will yield the shell geometry with a higher first natural frequency and thus a wind-insensitive structure. Linearly and nonlinearly numerical analysis are demonstrated influence of the shell-geometric parameters on structural behaviours. The results of this study may be informative for the form-finding of the cooling tower shell.
        280.
        2012.02 KCI 등재 서비스 종료(열람 제한)
        본 논문은 수중체용 냉각 시스템에 관하여 분석하고, 수중체에 최적화된 냉각 제어 알고리즘에 관하여 연구하였다. 수중체용 대용량 추진 전동기는 동손 및 철손으로 인해 발생하는 고열로부터 전동기를 안정적으로 보호하기 위해 청수를 이용한 냉각 시스템이 사용된다. 이 냉각 시스템은 전동기의 온도를 유지하기 위해 외부 환경 및 전동기의 회전수 유지시간에 따라 해수 및 청수 펌프 RPM을 조절한다. 본 논문에서는 제안하는 냉각 시스템의 검증을 위한 시뮬레이션 프로그램을 구성하였으며, 다양한 제어 기법을 적용하여 냉각 수행 능력을 검증하였다. 그 결과 제안하는 냉각 알고리즘은 열적 안정성과 효율이 기존 냉각 알고리즘에 비해 높음을 확인하였다.