• Title/Summary/Keyword: Wind climate

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Thermal and Water Transmission Properties of Vapor Permeable Water Repellent Fabrics and Thermal Insulation Batting Materials (투습발수직물과 보온단열소재의 열 및 수분전달 특성)

  • Cho Gil Soo;Choi Jong Myoung;Lee Jung Ju;Lee Sern Woo
    • Journal of the Korean Society of Clothing and Textiles
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    • v.16 no.2
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    • pp.237-244
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    • 1992
  • The purpose of this study was to comparatively evaluate thermal and water transmission properties of several vapor permeable water repellent (VPWR) fabrics and synthetic battings that became available in recent years. Five VPWR fabrics evaluated were Hipora in three coating variants, $Gore-Tex^{\circledR}$ and $Aitace^{\circledR}$. Battings evaluated were $Viwarma^{\circledR}$, $Uniwarmr^{\circledR}$, $Thinsulate^{\circledR}$, and $Airseal^{\circledR}$ Thermal resistance and water vapor transmission were measured for each fabric and batting and in all combinations. Thermal resistance at zero and 37 cm/sec air velocity was determined by the Thermo Labo II technique for simultaneously measuring conduction and radiation heat transfer. Water vapor transmission over 24 hours was measured by a modified weight-gain method in a compact humid chamber at conditions simulating the clothing climate under heavy exercise ($40{\pm}1^{\circ}C$, $90{\pm}2\%$ R.H., and 0.5 m/sec air velocity). Fabric porosity was calculated from fiber density and fabric weight, thickness, and area. Thermal resistance results for the fabrics showed the effectiveness of coatings in inhibiting heat transfer. Measurements taken in wind were: $31.1\~37.6\%$ for $Hipora^{\circledR}$ variants; $31.0\%$ for $Gore-Tex^{\circledR}$; and $18.4\%$ for $Aitaca^{\circledR}$ Measurements without wind were higher but in the same order. Water vapor transmission results were in reverse order: $Aitac^{\circledR}$, $8.8 kg/m^{2};\;Gore-Tex^{\circledR}$, 6.4 kg/$m^{2}$; and $Hipora^{\circledR},\;4.4\~6.0\;kg/m^{2}$. In general thermal resistance increased with porosity. For battings, the thermal resistance with wind results were: $Viwarmu^{\circledR}$, $65.0\%;\; Thinsulate^{\circledR}$, $62.0\%$; $Uniwarm^{\circledR}$, $61.0\%$; and $Airseala^{\circledR},\;53.1\%$. Thermal resistance was proportional to thickness. Thermal resistance of fabric-batting combinations were $20\%$ higher than those of the battings only. Water vapor transmission for combinations was mainly affected by that for the VPWR fabric used.

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A Simulation Model for the Study on the Forest Fire Pattern (산불확산패턴 연구를 위한 시뮬레이션 모델)

  • Song, Hark-Soo;Jeon, Wonju;Lee, Sang-Hee
    • Journal of the Korea Society for Simulation
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    • v.22 no.2
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    • pp.101-107
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    • 2013
  • Because forest fires are predicted to increase in severity and frequency under global climate change with important environmental implications, an understanding of fire dynamics is critical for mitigation of these negative effects. For the reason, researchers with different background, such as ecologists, physicists, and mathematical biologists, have developed the simulation models to mimic the forest fire spread patterns. In this study, we suggested a novel model considering the wind effect. Our theoretical forest was comprised of two different tree species with varying probabilities of transferring fire that were randomly distributed in space at densities ranging from 0.0 (low) to 1.0 (high). We then studied the distributional patterns of burnt trees using a two-dimensional stochastic cellular automata model with minimized local rules. We investigated the time, T, that the number of burnt trees reaches 25% of the whole trees for different values of the initial tree density, fire transition probability, and the degree of wind strength. Simulation results showed that the values of T decreased with the increase of tree density, and the wind effect decreased in the case of too high or low tree density. We believe that our model can be a useful tool to explore forest fire spreading patterns.

The Analysis of the Weather Characteristics by Source Region of the Asian Dust Observed in South Korea (한국에 출현한 황사의 발원지별 기상 특성 분석)

  • Kim, Sunyoung;Lee, Seungho
    • Journal of the Korean Geographical Society
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    • v.48 no.2
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    • pp.167-183
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    • 2013
  • This paper aimed to investigate the Asian dust source region and climatic condition of source region by the case of Asian dust in south Korea. In order to analyze the weather condition of source region, observed the Asian dust days data and weather data in China were used. The Asian dust days originating from inner-Mongolia were the most frequent. The Asian dust days originating from all the source regions except Loess plateau were increased recently and occurred over the country. In case of Loess plateau, the frequency of the Asian dust days in 1960s was the highest and only the southern region of the south Korea was mostly affected. The relationship between the Asian dust days of Korea and climatic factors of spring and April of source region was significant. The relationship between the Asian dust days originating from the inner Mongolia and sea level pressure of April and relative humidity of spring was negative. The Asian dust days from Gobi had positive relationship with wind gust days and negative relationship with sea level pressure in April. The Asian dust days from Manchuria had negative relationship with precipitation and sea level pressure in April. The Asian dust days from Loess plateau had positive relationship with maximum wind speed and negative relationship with sea level pressure in April.

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Mutual Adjustment of Oceanographic Measurements from leodo Station and Satellite Data (원격탐사자료와 이어도기지 해양관측자료를 이용한 상호 보정)

  • Kim Chang-Oh;Shim Jae-Seol;Hwang Jong-Sun;Lee Jae-Hak;Kim Soodung;Kim Jeong Woo
    • Korean Journal of Remote Sensing
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    • v.21 no.2
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    • pp.113-120
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    • 2005
  • Oceanographic measurements from Ieodo Ocean Research Station and its vicinity were compared for assessment and mutually adjusted with satellite data. From the Topex/Poseidon and ERS-1/2 radar altimeter and scatterometer data, sea surface height, wind speed and direction were extracted and analyzed. Shipborne wind direction data acquired in June 1995 show good coherence with the satellite data, while sea surface height and wind speed show differences, possibly resulting from the distance between the measurement points. This can be improved by analyzing more satellite data or using other available shipborne data. The recent 3 months of Ieodo Station data between December 2004 and February 2005 were also analyzed and compared with the satellite data. The Ieodo Station data were found to have considerable gaps during the period as well as seriously biased particular when the data were averaged with some abnormal data. The Ieodo Station and satellite data were then mutually adjusted on the basis of their statistics. Ieodo Station oceanographic measurements are very efficient for ground-frothing of satellite data because they are stationary and the station is located far from the coast. On the other hand, the satellite measurements are the only data to fill up gaps and adjust biases of the Ieodo Station data.

The Study on the Environmental Factors of Atopic Dermatitis in Oriental-Western Medicine (아토피 피부염의 환경적 요인에 대한 동서의학적 고찰)

  • Park, Sung-gu;Noh, Hyeon-Min;Kweon, So-Hyoun;Jo, Eun-Hee;Jang, Hyun-Chul;Kim, Ho-kyoung;Park, Hi-Joon;Kim, Won-Jeong;Park, Min-Cheol
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.31 no.1
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    • pp.52-70
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    • 2018
  • Objectives : Atopic dermatitis(AD) and environmental factors are closely related, but there is lack of oriental medical examination. So we compared the relationship between AD and various environmental factors in Oriental medicine and Western medicine. Methods : We described the relationship between AD and environmental factors through the latest papers and a review of the oriental medicine literature. Results : The regional diversity of AD incidence implies a close relationship between climate factors and AD, and high altitude and low pH springs also have an effect on AD. Air pollutants from industrialization and urbanization aggravate AD. The increase in indoor residence time and the increase in room temperature and humidity have also increased the sensitization to allergens such as house dust mite. In oriental medicine, wind(風) is one of the environmental factors and is an inflammatory state due to external irritation. Wind-Humidity(風濕) refers to erythematous wetting dermatitis with itching and exudation, Wind-Fever(風熱) refers to acute inflammatory reaction with erythematous papules and plague, and Blood-Weakness(血虛) refers to aggravation and chronicization of inflammation due to persistence of skin barrier impairment. Conclusions : We examined the relationship between AD and various environmental factors. We also described the oriental medical viewpoints of the environmental factors in the occurrence of AD and skin barrier impairment.

Design of ICT based Protected Horticulture for Recovering Natural Disaster (ICT기반 시설원예 재해 경감장치 설계)

  • Lee, Meong-Hun;Yoe, Hyun
    • Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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    • v.6 no.10
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    • pp.373-382
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    • 2016
  • Under the Agricultural technology is influenced from climate that is requisite of seasonal. So this system will cover the problems and develop the agricultural industry as well. So far, the agricultural industry is developing however, it has the points of the weakness because of natural disasters such as wind risk and heavy snow. This paper designs system to change vinyl on the greenhouse. This is a preliminary study for the real-time feedback control of greenhouse. The study developed a wireless IoT sensor system based on authentic technology capacities, to integrate with the protected horticulture Management System. These system was used to evaluate the levels of the snow cover and wind through IoT devices. The existing greenhouse uses the warm water to clear snow or to change methods. This system will recover by changing the vinyl which is covered outside of the greenhouse. The points of the system is changing vinyl to spin pipe. It is contained extra vinyl. The effects of this system are minimized labor protected crops from natural disasters. For this purpose, the study first developed a wireless IoT sensor unit that integrates an MEMS device and wireless communication module. Also, the study developed an operating program that enables real-time response measurement. It will help operational and maintenance greenhouse as a result.

Comparisons of the Pan and Penman Evaporation Trends in South Korea (우리나라 증발접시 증발량과 Penman 증발량 추세 비교분석)

  • Rim, Chang-Soo
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.5B
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    • pp.445-458
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    • 2010
  • The effects of geographical and climatic factors on annual and monthly pan and Penman evaporation were analyzed. 52 climatological stations were selected and trend analyses were performed. Furthermore, cluster analysis and multiple linear regression analysis were performed to understand the effects of geographical and climatic factors on pan and Penman evaporation. Based on stepwise multiple linear regression analysis, annual pan evaporation is proved to be mainly controlled by urbanization as geographical factor, and annual pan evaporation is also controlled by temperature, relative humidity, wind speed, and solar radiation as climatic factor. Especially wind speed is considered to be most significant climatic factor which affects pan evaporation. Meanwhile, Penman evaporation is not affected by geographical factors but it is affected by climate factors such as temperature, relative humidity, wind speed, and solar radiation except precipitation. Furthermore, the study results show that only proximity to coast affects pan evaporation trend on July; however, geographical and climatic factors do not affect pan evaporation trends in annual basis and monthly basis (January, April, and October). On the other hand, Penman evaporation trends were not affected by geographical factors in annual and monthly basises.

Study on Effectiveness of Ocean Meteorological Variables through Sensitivity Analysis of Ship Infrared Signature (함정 적외선신호 민감도 해석을 통한 기상변수 영향에 관한 연구)

  • Cho, Yong-Jin;Jung, Ho-Seok
    • Journal of Ocean Engineering and Technology
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    • v.27 no.3
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    • pp.36-42
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    • 2013
  • According to a study on improving ship survivability, an IR signature represents the contrast radiance intensity between the radiation signature from a ship and the background signature. It was found from applying stealth techniques to the process of ship development that the IR signature is remarkably sensitive and dependent on the environment. In this study, marine climate data for the sea near the Korean Peninsula were collected, and the marine meteorological environment in Korean waters was defined. Based on this data, a study on the sensitivity of the IR signature of target objects was performed using analytical methods. The results of the research indicated that clouds have important effects on the infrared signature, but the velocity of the wind and the humidity have only slight effects on the IR signature. In addition, the air and seawater temperatures had hardly any effect on the IR signature, but it is judged that additional study is needed.

Analysis for Annualized Returns of Island Microgrid IPP According to CER Price (CER 가격에 따른 도서지역용 MG 발전사업자의 연평균수익률 분석)

  • Kim, Mi-Young
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.4
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    • pp.512-521
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    • 2018
  • Islands that is far away from onshore have used internal-combustion engine driving alternators to secure electric power. However, with Paris convention on climate change, there is a growing interest in eco-friendly energy independent island that replaces microgrid(MG) consisting of photovoltaic, wind power, and energy storage system with alternators for internal combustion engines. And also, national emission trading has been implemented, and the price of certified emission reduction(CER) has a influence on system marginal price(SMP). Because, the low cost generation source decides SMP when CER price is low, while the more expensive generation source decides SMP when CER price is high. Therefore, the increasing of CER price has a strong influence on the annualized return of MG independent power producer. Moreover, the fixed RPS price is implemented from 2017, which the increasing of CER price under the fixed RPS price or the variable RPS price affects annualized return differently. In this paper, the annualized return according to CER price is analyzed for large, middle, and small scaled islands, the effect of CER price on the annualized return was confirmed.

On the Seasonal Variation of Urban Heat Island Intensity According to Meteorological Condition in Daegu (대구지역의 기상조건에 따른 도시열섬강도의 계절별 변화특성)

  • Ahn Ji-Suk;Kim Hae-Dong
    • Journal of Environmental Science International
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    • v.15 no.6
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    • pp.527-532
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    • 2006
  • The purpose of this study is to clarify the characteristic of urban heat island intensity in urban area formed at a basin. Thermal environments for basin-type cities are influenced by significant topographic relief winds. In this study, we analyzed the diurnal variations of the heat island intensity according to meteorological condition and season using AWS(Automatic Weather observation System) data in Daegu Metropolitan area for 1 year(3/April, 2003 $\sim$ 2/April, 2004). In this study, we defined the urban heat island intensity as the air temperature difference between two points, the downtown and the suburban area. The suburban area is located at valley mouth around the western tip of Daegu. The results are summarized as follows; 1. The maximum heat island intensity was recorded at early morning under the meteorological conditions, calm and clear 2. The heat island intensity was strong in the order of winter, fall, spring and summer. 3. The heat island intensity came out minus values in the afternoon. This phenomenon is known as a com mon for basin-type cities. 4. The heat island intensity was twice or more in clear and calm than not so.