• Title/Summary/Keyword: Relative Temperature

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Changes of the Physical Properties of Corrugated Fiberboard Boxes for Fruit and Vegetable Packaging by Preservation Temperature and Relative Humidity (과채류 포장용 골판지 상자의 저장온도와 습도에 따른 물리적 특성 변화)

  • Lee, Myung-Hoon;Cho, Jung-Yeon;Shin, Jun-Seop
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.34 no.1
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    • pp.46-53
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    • 2002
  • This study was carried out to analyze the effects of preservation temperature and relative humidity to the physical properties of corrugated fiberboard boxes for fruit and vegetable packaging. The preservation temperature did not affect severely to physical properties of corrugated fiber-board. Relative humidity was a major cause of corrugated fiberboard box quality deterioration. The burst and compressive strengths of experimental boxes measured with Mullen high pressure tester and tong crush tester were decreased gradually as relative humidity increased from 55% to 75%. But, the strength properties slightly decreased relative humidity at 75% or higher. This tendency was the greater for single wall (SW) corrugated fiberboard box than that for double wall (DW). It is suggested that development of the water-resistant corrugated fiberboard and box be needed that can be used under the condition of low temperature and high moisture content, which are being employed in the cold chain system.

Comparison Study of Air Temperature by Green Condition and Relative Humidity (녹지 조건에 따른 기온 및 상대습도의 비교연구)

  • 윤용한
    • Asian Journal of Turfgrass Science
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    • v.15 no.3
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    • pp.111-118
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    • 2001
  • We observed air temperature and relative humidity in the green space why this research graspes effect of climate relax by coverage condition and height difference tree in green space of the 4ha scale. With this data, analyzed relationship of coverage and air temperature or relative humidity distribution, number of tree and climate relax by revolution analysis. In this result, higher zone formed barren area, lower zone did forest and surround grassland. Relative humidity have corresponding type of air temperature distribution. higher air temperature zone was lower humidity and lower zone was higher humidity. Coverage condition effect climate relax by increasing forest and grassland. and increasing number of tree effect climate relax no related hight of tree. This efficiency order of an arbor, subarbor.

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An Experimental Study on Temperature Measurement Bias using Thermocouple in Simulated Thermal Environments of Fire (모사된 화재의 열적환경에서 열전대를 이용한 온도 측정오차에 관한 실험적 연구)

  • Han, Ho-Sik;Yun, Hong-Seok;Hwang, Cheol-Hong;Kim, Sung-Chan
    • Journal of the Korean Society of Safety
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    • v.32 no.2
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    • pp.7-13
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    • 2017
  • An experimental study was conducted to identify the quantitative measurement bias for the bare-bead thermocouple (TC), which was widely used for measuring temperature in fire experiments. To this end, an apparatus could be controlled individually gas flow rate, preheating temperature and incident radiative heat flux was developed to simulate the thermal environments of fire. A relative measurement bias of bare-bead TC was evaluated with the comparison of double-shield aspirated TC. As a result, the relative measurement bias of bare-bead TC was gradually increased with the increase in radiative heat flux with constant gas temperature. The relative bias was also significantly increased with the decrease in gas temperature. Quantitatively, at the gas temperature of $20^{\circ}C$, the bare-bead TC had the relative bias of approximately 400% with the radiative heat flux of $20kW/m^2$ corresponding to thermal radiation level of the flashover. The present study was intend to provide fire researchers with methodologies for the reanalyses of temperature measured using bare-bead TC, radiation corrections, and validation of fire modeling.

A study on the Characteristics of Urban Dryness in Daegu (대구의 도시건조화 특성에 관한 연구)

  • Park, Myung-Hee;Kim, Hae-Dong
    • Journal of Environmental Science International
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    • v.16 no.2
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    • pp.171-178
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    • 2007
  • It is well known that urban relative humidity has continuous decreasing trend owing to the influence of urbanization. The change of relative humidity is directly influenced by two factors, namely, temperature effect and water vapor effect in various urban effects. In this study, the temperature and tile water vapor effects on the relative humidity change were analyzed by using monthly mean relative humidities for a long period($1961{\sim}2005$) in Daegu and Chupungnung. The major results obtained in this study can be summarized as follows. Firstly, the urban dryness was caused mainly by water vapor effect in summer. But, for the other seasons, the urban dryness is mainly due to the temperature effect. Secondly, the relative humidity in Daegu is on the decrease until now. This phenomenon is similar to another Korean huge cities such as Seoul, Daejeon and Incheon. But, it is different compared with Japanese huge cities such as Tokyo, Osaka and Nagoya, indicating a standstill in relative humidity change after 1980s.

A Study on the Control of the Temperature and Relative Humidity in Greenhouse by Adjusting the Amount of Natural Ventilation and Fog Spray Quantity (자연환기량과 포그분무량 조절에 의한 온실 온습도의 동시제어 기법 연구)

  • Kim, Youngbok;Sung, Hyunsoo;Hwang, Seungjae;Kim, Hyeontae;Ryu, Chanseok
    • Journal of the Korean Solar Energy Society
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    • v.36 no.5
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    • pp.31-50
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    • 2016
  • To develope a greenhouse fog cooling system to control the temperature and relative humidity simultaneously to the target value, a theoretical analysis and experiments were done. The control process includes the measuring of environmental variables, setting and coding of the water and heat balance equations to maintain the target temperature and relative humidity in greenhouse, calculating of the open level of the greenhouse roof window that governs the natural ventilation and spray water quantity, and operating of the motor to open/close the roof window and pump to spray for water. The study results were shown to be very good because the average air temperature in the greenhouse was kept to be about $28.2^{\circ}C$ with the standard deviation of about $0.37^{\circ}C$ compared to the target temperature of $28^{\circ}C$ and the average relative humidity was about 75.2% compared to the target relative humidity was 75% during the experiments. The average outside relative humidity was about 41.0% and the average outside temperature was $27.2^{\circ}C$ with the standard deviation of about $0.54^{\circ}C$. The average solar intensity in the greenhouse was 712.9 W. The wind velocity of outside greenhouse was 0.558 m/s with the standard deviation of 0.46 m/s.

Characteristics of Meteorological Environment Variation Before and After Construction of Nak-dong River Estuary Barrage (낙동강 하구둑 건설 전·후의 기상환경 변화 특성)

  • Jeon, Byung-Il
    • Journal of Environmental Impact Assessment
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    • v.14 no.3
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    • pp.135-145
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    • 2005
  • This study was conducted to investigate the characteristics of meteorological environment variation before and after construction of Nak-dong river estuary barrage. We used meteorological data(air temperature, precipitation, relative humidity, visibility, wind) at Gimhae airport meteorological station. The construction of river estuary barrage can change climate at the neighboring districts and influence human's health and vegetable. The construction of Nakdong river estuary barrage brought rise of temperature, decrease of relative humidity and increase of poor visibility frequency.

Development of an Environmental Control System for Agricultural Storage Facility (상온저장 시설의 환경 제어 시스템 개발)

  • 임종환;현명택
    • Food Science and Preservation
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    • v.4 no.2
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    • pp.101-113
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    • 1997
  • Temperature, relative humidity and ventilation are closely related one another, and they are the main factors to be controlled for the environmental control system of a storage facility. Conventional environmental control systems do not consider the interrelationship between temperature, relative humidity and ventilation, which results in low performance and high energy consumption. To overcome the inefficiency of the conventional ones, it was developed an on-off control system based on the interrelationship between the factors. The usefulness of the system was illustrated with the results produced by a set of experiments in a real world.

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Experimental Study on the Moisture Distribution in Concrete Specimens According to Different Compressive Strengt (콘크리트 강도차에 따른 함수율 분포의 변동에 관한 실험적 연구)

  • Park, Dong-Cheon
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2019.05a
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    • pp.195-196
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    • 2019
  • The temperature and relative humidity in concrete change with the passage of time depending on factors such as compressive strength. They are also different depending upon internal depth of concrete. In this study, we have measured the change of the temperature and relative humidity in the concrete for two years to act as the parameters to evaluate the concrete durability and effective maintenance.

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Microwave Dielectric Properties of ZST Ceramics for Mobile Telecommunication System (기지국용 ZST세라믹스의 소결조건에 따른 고주파 유전 특성)

  • 서정철;이희영
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.07a
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    • pp.636-639
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    • 2000
  • Effects of sintering temperature and time on relative permittivity $\varepsilon$$\_$r/, unloaded quality factor Q$.$f and temperature coefficient of resonant frequency $\tau$$\_$f/ of dielectric resonator materials produced from commercial ZST powder were investigated in some detail. Q$.$f values, as determined from cavity perturbation method at 1.6 GHz, gradually increased with sintering temperature reaching the maximum at 1420$^{\circ}C$. However, bulk density and relative permittivity values, which increased with temperature, started to decrease above 1380$^{\circ}C$. In addition, Q$.$f values slightly increased with sintering time at the sintering temperature of 1300$^{\circ}C$∼1380$^{\circ}C$, while bulk density and relative permittivity values were approximately constant. It was also found that $\tau$$\_$f/ values were not affected by sintering temperature and time within the experimental conditions used.

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The Changes of Meteorological Environment by Urban Development (대규모 도시 재개발에 따른 기상환경변화)

  • Kim, Geun-Hoi;Kim, Yeon-Hee;Koo, Hae-Jung;Kim, Kyu-Rang;Jung, Hyun-Sook
    • Atmosphere
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    • v.24 no.1
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    • pp.69-76
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    • 2014
  • Urbanization affects the local thermal environment due to the large scale land use changes. To investigate the weather environment change of large scale urban redevelopment, 9 surface temperature and humidity observations were accomplished at Eunpyeong new town area. The observation period is from March 2007 to February 2010. In the center of development area, the air temperature has increased and relative humidity has decreased, by the changes of the land cover and building construction. In the area where the green zone is maintained, air temperature and relative humidity were not changed significantly. The air temperature and relative humidity for the other development observation stations is decreased and increased, respectively. The relative temperature difference between study area and a neighboring rural location was increased during observation periods. The difference is the highest during winter. The urban-rural minimum temperature difference was increased at development area, which means that urbanization affects increasing of minimum temperature in study area.