• Title/Summary/Keyword: hot and cold environment

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Antioxidative Effects of Extracts of Various Cultivars and Different Plant Parts of Eggplant (가지의 품종별, 부위별 추출물의 항산화 효과)

  • Beik, Kyung-Yean;Lee, Sang-Il;Kim, Jeong-Sook;Lee, Doo-Young;Oh, Seoung-Hee;Kim, Soon-Dong
    • Journal of the East Asian Society of Dietary Life
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    • v.19 no.2
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    • pp.195-201
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    • 2009
  • The antioxidative activities of two varieties of egg plant (Chunyang No 2: Dangaji, Jinju Janggaji: Janggaji) extracts were investigated. The total polyphenol contents of Dangaji peel hot water extract and the Janggaji flesh and fruit hot water extracts were higher than those of the other samples. However, the DPPH radical scavenging activities(electron donating activity) of Dangaji flesh-ethanol, peel-cold water, and fruit- ethanol extracts, as well as the Janggaji peel cold water extract, were higher than those of the other samples. Furthermore, the in vitro inhibitory effects of the Dangaji peel cold water and hot water extracts on rat hepatic xanthine oxidase were highest among the samples, and were exhibited in a dose dependant manners. Although there were marked changes in the xanthine oxidase Km values for xanthine as a substrate, the Vmax value changes by the addition of the Dangaji water extracts were minor compared with the control. This result suggests that Dangaji water extracts may regulate the activity of xanthine oxidase-via the inhibition of binding affinity between the enzyme and substrate. The present study provides experimental evidence that constituents of egg plant extracts may ameliorate reactive oxygen species(ROS)-induced oxidative stress via hepatic hepatic xanthine oxidase activity, but further studies to identify the active antioxidants and compounds and inhibitors of xanthine oxidase are required.

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Effect of Body Fat on Thermophysiological Responses at a Hot Environment (체지방률이 서열환경하의 온열생리에반응에 미치는 효과)

  • Kim, Hee-Eun;Kim, Seong-Suk
    • Fashion & Textile Research Journal
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    • v.6 no.4
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    • pp.515-521
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    • 2004
  • The Purpose of this study was to investigate the effect of body fat on thermophysiological responses and subjective sensations under hot environment. Fifteen female college students volunteered as subjects. Subjects were organized into three groups - low body fat group(L group : less than 20% of body fat), medium body fat group(M group : 20%~30% of body fat) and high body fat group(H group : More than 30% of Body fat). The experiment was carried out in a climate chamber of $32^{\circ}C$, 60%RH with the repeat of having 'Exercise' and 'Rest' period. The results of this study are as follows ; Rectal temperature maintained higher in M group and L group than in H group in the period of exercise 1. High body fat was so effective in keeping the core temperature, it seems that as was usually the case in cold environment. The mean skin temperature was the lowest value in H group but the ratio of mean skin temperature change was clearly high value in H group. The above facts indicated that thermophysiological response occurs rapidly in H group. Blood pressure, pulse rate and metabolic rate of H group showed the highest values and those of L group showed the lowest value in all period of experiment. Effective of sweating rate was higher in H group than other groups. In subjective sensations, The H group felt more pleasant and comfortable than M group. With these results in mind, people of H group responses more actively for thermal regulation in a hot environment, and these leads H group to feel more pleasant and comfortable.

A Study on Concrete Material Quality Management Based on Various Test of Construction Condition under Hot Weather Circumstance (서중(暑中) 환경에서 현장 콘크리트 시험을 통한 재료 품질관리 방안)

  • Park, Shin
    • Journal of the Korea Institute of Building Construction
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    • v.5 no.3 s.17
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    • pp.91-99
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    • 2005
  • It is required to study systematical on the concrete quality management to extend structure life because rebuilding effect is reducing under present condition of large sized and high stories structure. Concrete, which shows its intensity by hydrating action and a big change in quality according to hot weather and temperature, produces a lot of qualify problem under hot and cold weather Because of each specification and construction plan which does not have basic standard on site, concrete's quality is irregular and makes some defect. As a result, Daegu is turned out to be the longest area after investigating application period and days focused on 8 cities weather information about relationship between hot weather circumstance and construction environment. Therefore, we first surveyed the concrete material in the region and found out the problem of quality nanagement. Then figure out the way of solution. Moreover, we integrated concrete material quality management, which is applied differently to each site, to have equal quality and to reduce defect from construction site. And then, based on various test of construction condition and analysis of quality management item, we suggest effective concrete quality management to make concrete material construction standard guide and plan under hot weather.

The evolution of a late-type galaxy in a Coma-like cluster

  • Hwang, Jeong-Sun;Park, Changbom;Banerjee, Arunima
    • The Bulletin of The Korean Astronomical Society
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    • v.41 no.2
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    • pp.64.1-64.1
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    • 2016
  • We study the evolution of a late-type galaxy (LTG) in a rich cluster environment by using N-body/SPH simulations. To do that we perform a set of simulations of a LTG falling in a Coma-like cluster and also the LTG colliding with early-type galaxies (ETGs) multiple times in the cluster environment. We use a catalog of the Coma cluster in order to estimate the typical number of collisions and the closest approach distances that a LTG would experience in the cluster. We investigate the cold gas depletion and star formation quenching of our LTG model influenced by the hot cluster gas as well as the hot halo gas of the colliding ETGs.

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Characterization of Indoor Temperature and Humidity in Low-income Residences over a Year in Seoul, Korea

  • Lee, Daeyeop;Lee, Kiyoung;Bae, Hyunjoo
    • Asian Journal of Atmospheric Environment
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    • v.11 no.3
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    • pp.184-193
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    • 2017
  • People spend the majority of their time in indoor environments. Maintaining adequate indoor temperature and humidity is necessary to support health and improve quality of life. However, people with low incomes can be vulnerable because they may not be able to use effective cooling and heating systems in their homes. In this study, the indoor temperature and humidity in low-income residences over a year in Seoul, Korea was characterized. Indoor temperature and humidity were measured in three types of homes (12 rooftop residences, 16 basement residences, and 18 public rental apartments) occupied by low-income residents. Both differed significantly among the three types of residence, particularly during the summer and winter seasons. A regression model between indoor and outdoor temperature detected a heating threshold at $3.9^{\circ}C$ for rooftop residences, $9.9^{\circ}C$ for basement residences, and $17.1^{\circ}C$ for public rental apartments. During tropical nights and cold-wave advisory days, rooftop residences showed the most extreme indoor temperatures. This study demonstrates that people living in rooftop residences could be at risk from extreme hot and cold conditions.

Study on the mixing performance of mixing vane grids and mixing coefficient by CFD and subchannel analysis code in a 5×5 rod bundle

  • Bin Han ;Xiaoliang Zhu;Bao-Wen Yang;Aiguo Liu;Yanyan Xi ;Lei Liu ;Shenghui Liu;Junlin Huang
    • Nuclear Engineering and Technology
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    • v.55 no.10
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    • pp.3775-3786
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    • 2023
  • Mixing Vane Grid (MVG) is one of the most important structures in fuel assembly due to its high performance in mixing the coolant and ultimately increasing Critical Heat Flux (CHF), which avoids the temperature rising suddenly of fuel rods. To evaluate the mixing performance of the MVG, a Total Diffusion Coefficient (TDC) mixing coefficient is defined in the subchannel analysis code. Conventionally, the TDC of the spacer grid is obtained from the combination of experiments and subchannel analysis. However, the processing of obtaining and determine a reasonable TDC is much challenging, it is affected by boundary conditions and MVG geometries. In is difficult to perform all the large and costing rod bundle tests. In this paper, the CFD method was applied in TDC analysis. A typical 5 × 5 MVG was simulated and validated to estimate the mixing performance of the MVG. The subchannel code was used to calculate the TDC. Firstly, the CFD method was validated from the aspect of pressure drop and lateral temperature distribution in the subchannels. Then the effect of boundary conditions including the inlet temperature, inlet velocities, heat flux ratio between hot and cold rods and the arrangement of hot and cold rods on MVG mixing and TDC were studied. The geometric effects on mixing are also carried out in this paper. The effect of vane pattern on mixing was investigated to determine which one is the best to represent the grid's mixing performance.

Analysis of Heat Environment in Nursery Pig Behavior (자돈의 행동에 미치는 열환경 분석)

  • Sang, J.I.;Choi, H.L.;Jeon, J.H.;Jeon, B.S.;Kang, H.S.;Lee, E.S.;Park, K.H.
    • Journal of Animal Environmental Science
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    • v.15 no.2
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    • pp.131-138
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    • 2009
  • This study was conducted to find ways to control environment with the difference between body temperature and background temperature based on swine activity, and to apply to the environment control system of swine barns based on the findings. Following are the results. 1. Swine activity related to background temperature was achieved as color images and swine activity status was categorized into cold, comfortable, and hot periods with visualization system (thermal image system). 2. Thermal image system consisted of an infrared CCD camera, an image processing board - DIF (TH3100), an main computer (400Hz, 128M, 586 Pentium model) with C++ program installed. 3. Thermal image system categorizing temperatures into cold, comfortable, and hot was applicable to the environment control system of swine barns 4. Feed intake was higher in cold temperature, and finishing weight and weight gain per day in cold temperature were lower than others (p<0.05).

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The Study on the Effect of Passenger Coach temperature When Aircurtains Installed At Electrical Rolling Stock At Entrance Door (전동차 출입문에 에어커튼 설치시 객실 온도 변화 연구)

  • Ahn Jong-Kon;Kim Chul-Ho;Park Duk-Sin
    • Proceedings of the KSR Conference
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    • 2004.10a
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    • pp.489-496
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    • 2004
  • The effect of airconditioning and heating system when aircurtains installed in subway electrical rolling stock at entrance door. It blocks cold/hot air of outside. It is good for health with its blocking effect against dusts exhaust fumes, odor bugs and smoke from outside. It always maintains clean and pleasant atmosphere inside. It helps you to have health with its ever-equal temperature distribution at inside. It saves lots of maintenance cost for heating/cooling (about 86$\%$) since it cuts the loss of hot air under heating as well as of cold air under air-conditionin. Customers can feel pleasant go in and out (better than before) with the door. It is an indispensable product for the employers to cut the cost. It makes customers feel pleasant near doors, since it isnt influenced by temperature difference of cold/hot air when the door opens/closes. In electrical rolling stock passenger temperature is a lot different from that the door opens/closes. One of the main aims is to create an acceptable thermal environment without draught problem. Temperature, gradients when aircurtains installed in subway electrical rolling stock at entrance door have been studied. And the temperature measured at 0.1, 0.5, 1.3, 1.7m above the floor. It has been found that temperature, with large fluctuations caused more draught influence.

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Temperature Change in the Largest Industrial City, Korea

  • Lee, Byeong-Kyu;Lee, Sang-Tae
    • Asian Journal of Atmospheric Environment
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    • v.9 no.3
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    • pp.194-204
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    • 2015
  • This study analyzed a change trend of ambient temperature over the last sixty years in the largest industrial city in Korea, Ulsan. Linear warming rates in Ulsan over the last 25 (1985 to 2009), 40 (1970 to 2009), and 60 (1950 to 2009) years were 0.0507, 0.0416, and $0.0277^{\circ}C/yr$, respectively. The annual average temperature (AAT) and the annual average of the daily lowest temperature (AADLT) in Ulsan increased 1.3 and $2.9^{\circ}C$, respectively, over the last fifty years (1960 to 2009). The increasing slopes of the AAT and AADLT over the fifty years in Ulsan were higher or much higher than those in neighboring cities and on a global scale. In the comparison analysis of daily average temperature over the most recent ten years, the highest ($15.9^{\circ}C$) was observed in the industrial area followed by the downtown, coastal, suburban, and rural areas with 14.6, 14.5, 14.0, and $12.8^{\circ}C$, respectively. The number of cold days less than $5.0^{\circ}C$ decreased, while the number of hot days higher than $20.0^{\circ}C$ increased. The decreasing slopes in the cold days in lower latitude cities were steeper than those in higher latitude cities in Korea.

Studies on the Emission control of methanol engine exhaust with modified 3-way catalyst at cold start condition (변형된 삼원촉매에 의한 저온시동조건에서의 메탄올엔진 배가스 정화효과에 관한 연구)

  • 홍종성;정석진
    • Journal of Korean Society for Atmospheric Environment
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    • v.9 no.2
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    • pp.160-167
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    • 1993
  • As the major methanol fueled vehicle exhaust components, formaldehyde & methanol conversion over the existing commercial 3-way catalyst was examined in a labolatory tains different Ag loadings on commercial 3-way catalyst, and german commercial catalysts for methanol engine exhaust manufactured by a commercial manufacturer. Silver catalysts were prepared by the wet impregnation of silver nitrate solution on commercial 3-way catalyst. These catalysts were characterized with BET Surface area and pore size distribution. In general, the formaldehyde(HCHO) conversion of the tested catalysts was similar to that of methanol$(CH_3OH)$. At 100$^\circ$C, which is equivalent to the cold start condition, 5wt% Ag cat. showed the most excellent HCHO and $CH_3OH$ conversion. The order of activity for conversion of HCHO & $CH_3OH$ to carbon dioxide and water vapor was as follows ; 5wt% Ag/3-way cat.>2wt% Ag/3-way cat.>german cat. front(1) > german cat. rear(2) > 10wt% Ag/3-way cat.> commercial 3-wat catalyst. However there was no significant activity difference between those tested catalysts in the hot run condition of 400$^\circ$C. Therefore, it could be concluded that the Ag-modified 3-way catalyst was the most effective and practical catalyst system which could be capable of removal the HCHO and methanol at the special condition of low temperature such as cold start condition.

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