• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.27 no.5
• /
• pp.277-282
• /
• 2015

During hot and humid weather, air-conditioners consume a large amount of electricity due to the large amount of latent heat. Simultaneous usage of a dehumidifier may reduce latent heat and reduce electricity consumption. In this study, dehumidification performance was measured for a small-sized dehumidification rotor made of inorganic fiber impregnated with metallic silicate within a constant temperature and humidity chamber. Regeneration to dehumidification depends on ratio, rotor speed, room temperature, regeneration temperature, room relative humidity and frontal velocity to the rotor. Results demonstrate an optimum area ratio (1/2), rotor speed (1.0 rpm), and regeneration temperature ($100^{\circ}C$) to achieve a dehumidification rate of 0.0581 kg/s. As the area ratio increases, the optimum rotation speed and the optimum regeneration temperature also increase. Above the optimum rotor speed, incomplete regeneration reduces dehumidification. Above the optimum regeneration temperature, increased temperature variation between regeneration and dehumidification reduces dehumidification. Dehumidification rate also increases with an increase of relative humidity, dehumidification temperature and flow velocity into the rotor.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.27 no.5
• /
• pp.75-83
• /
• 2023

As part of a study to analyze the excessive camber occurring in prestressed concrete railway bridges, this paper presents a calculation method and analysis results for the creep coefficient which defines the increase in camber of a concrete structure over time. Using the creep coefficient formula of the design code, the coefficient is obtained by applying the climatic conditions (relative humidity and temperature) of 12 regions in Korea. The effects of differences in climatic conditions by region and starting time of load on the creep coefficient are analyzed. In order to properly calculate the creep, most of which occurs in the early stages of loading, a detailed analysis is performed by applying a time step analysis method to consider varying climate conditions through loaded period. The creep coefficient obtained by applying the average climate conditions of the region is similar to the average of the creep coefficients obtained by time step analysis. Through time step analysis, it is shown that the offset and overlap effects of relative humidity and temperature on the creep coefficient and the climate effect at the time of initial loading can be appropriately represented.

• Journal of Environmental Science International
• /
• v.22 no.12
• /
• pp.1671-1681
• /
• 2013

The study selected 10 regions among major Korean cities. Then the study classified the yearly change of relative humidity of those regions for 37 years based on 1996 (from 1974 to 2011) aimed at high temperature days, and examined them by stage regarding daily maximum temperature. For large cities and small cities, in general relative humidity had been likely to increase at high temperatures of $30^{\circ}C$ or over before 1996, whereas it has decreased since 1996. For suburban areas, relative humidity had been prone to diminish before 1996, whereas it has been likely to either increase since 1996 or rarely some of the cities have not shown any change. The increasing tendency of relative humidity before 1996 in large cities and small cities is believed to be because of an increase of the latent heat of vaporization by the supply of steam from cooling towers established in downtown areas. Meanwhile, the decreasing tendency from 1996 is concluded to be caused by the change from counter-current circular cooling towers, which produce a great quantity of steam including arsenic acid, to cross-flow cooling towers, which produce hardly any steam containing arsenic acid. This change was in accordance with the modification and pursuit of an urban planning law that ordered cooling towers that had been installed on rooftops be installed in the basement of buildings in consideration of a "Green network creation" project by the Ministry of Environment, urban beautification, concerns since 1996 over building collapses, and according to an argument that steam containing arsenic acid could be harmful to human health owing to chemicals contained in the water in the cooling tower in summer.

• Journal of Sensor Science and Technology
• /
• v.14 no.6
• /
• pp.395-401
• /
• 2005

A highly stable quartz crystal microbalance (QCM) that showed a stability of frequencies and exhibited a very low noise level has been developed. The long-term drift was <0.05 Hz/h over a period of 10 h, and the short-term rms (root mean square) noise was <0.015 Hz. Our QCM sensor was used as a humidity sensor employing a poly(methyl methacrylate) (PMMA) polymer film as a hygroscopic layer, which showed good characteristics in the relative humidity (RH) range of $2{\sim}90%$ RH. Comparing the characteristics of the QCM sensor with those of other types of humidity sensors employing PMMA film as a hygroscopic layer, and with other QCM sensors employing other hygroscopic layers is represented.

• The Research Journal of the Costume Culture
• /
• v.13 no.3 s.56
• /
• pp.406-413
• /
• 2005

This study performed the evaluation of skin temperature, heart rate, temperature and relative humidity of microclimate, and subjective sensation, such as thermal sensation, wet sensation and comfort sensation to estimate physiological responses of the human body and its comfortable feeling to the vitamin E fabric. Experiments were performed on the five healthy adult women whose average age was 21, at climate chamber in which temperature, relative humidity and air current were set up below $30{\pm}\;1^{\circ}C$, $50{\pm}\;15\%$ and 0.2m/s, respectively. Two kinds of clothes were used for experiments: unfinished sports clothes, with the same form and the same size, of short-sleeved knit shirt and long trousers made with $100\%$ cotton, and finished sports clothes printed with the vitamin E solution of the level of $0.88\%$. Exercises of walking (about 105 steps/minute) with the exercise intensity of 2.5 were performed for 20 minutes using treadmill. In result, the study showed significant difference (p<0.01) in average skin temperature between unfinished and finished sport clothes, and represented higher value with having unfinished sport clothes in wear than with finished one. The study also showed significant difference (p<0.01) in heart rate only during the period of exercise, and represented higher value generally with unfinished sport clothes than with finished one. There were significant differences not only in temperature of microclimate (p<0.01) but also in humidity of microclimate (p<0.05) between two sport clothes. As for the evaluation of subjective sensation, the study showed significant difference (p<0.05) in thermal sensation between the two kinds of sport clothes, significant difference in wet sensation only during the period of exercise, and significant difference (p<0.05) in comfort sensation only during the period of recovery.

• Journal of Conservation Science
• /
• v.35 no.3
• /
• pp.197-208
• /
• 2019

Biological damages of wooden cultural properties are closely related to the preservation of the environment; these damages can be accelerated because of rapid climate change. Therefore, to preserve cultural properties, it is important to understand environmental characteristics. This study aims to investigate the status of termite damage and the characteristics of major environmental factors such as micro-meteorology, meso-meteorology, and local-meteorology of the Josadang shrine in the Seonamsa temple at Suncheon. Damage was confirmed by visual observation and the response of the termite detection dog at the north-west corner. Also another damage was observed by the termite detection dog at the north-east corner. These pillars had lower surface temperature and higher moisture content compared with the pillars in the front. The mean temperature of the entire time was similar for the meteorologies; however, the relative humidity differed. High relative humidity, greater than 70%, was observed frequently. In particular, it was determined that the termite activity days were the most inside the Josadang shrine. The statistical analysis confirmed that there was a difference between the meteorology events through the F ratio. In addition, the difference of environmental factors with relative humidity and temperature was identified more great difference in relative humidity through the t-statistics of temperature and relative humidity. And then relative humidity was confirmed most great in the difference of meso-meteorology and local-meteorology.

• Journal of Environmental Health Sciences
• /
• v.38 no.2
• /
• pp.118-127
• /
• 2012

Objectives: This study was undertaken to assess the sanitary conditions in the kitchens of food court/cafeterias and determine seasonal variations. Methods: We measured environmental factors (air temperature, relative humidity, illumination intensity, noise level), and dropping airborne microbes (bacteria and fungi) in the kitchens of eight food court/cafeterias in four seasons (January, April, July, and October). Air temperature and relative humidity were measured with in/out thermo-hygrometers at 1.2-1.5 m above floor level. Illuminance measurement was performed through the multiple point method of Korean Standards (KS). Noise level was measured by the standard methods for the examination of environmental pollution (noise and vibration) of Korea. The estimation of dropping airborne bacteria and fungi was performed through use of Koch's method. Results: The highest kitchen air temperature was in July, and the lowest in January. The average temperature surpassed $21^{\circ}C$ throughout the seasons, suggesting a higher temperature than required for the safe handling of food. Humidity in all the kitchens was measured in the range of 50-60%. Half of the kitchens showed illumination intensities below 300 Lux in April. It was found that the sound pressure level of noise in almost all of the kitchens was higher than 85 dB (A). The highest levels of dropping airborne bacteria and fungi were noted in July. The numbers of airborne bacteria were higher than those of fungi. The levels of dropping airborne bacteria and fungi were affected by air temperature, relative humidity, season, and place. Conclusions: This study indicates that the kitchen environments were unqualified to supply safe food. The hygiene level of the kitchens should be improved.

• The Transactions of the Korean Institute of Electrical Engineers
• /
• v.45 no.1
• /
• pp.93-99
• /
• 1996

The formation properties and oxidation mechanism of electrochemically oxidized porous silicon(OPS) films have been studied. To examine the humidity-sensitive properties of OPS films, surface-type and bulk-type humidity sensors were fabricated. The oxidized thickness of porous silicon layer(PSL) increases with the charge supplied during electrochemical humidity sensor shows high sensitivity at high relative humidity in low temperature. The sensitivity and linearity can be improved by optimizing a porosity of PSL. (author). refs., figs.

• Korean Journal of Agricultural and Forest Meteorology
• /
• v.8 no.4
• /
• pp.250-259
• /
• 2006

This study looks into forest fire occurrence hazards according to the change of temperature and humidity over thirty years at interval of ten days. We used data from the forest fire inventory from 1995 to 2004 and weather data such as average temperature and relative humidity for 30 years from 1971 to 2000. These data were expressed as a database with ten-day intervals for 76 weather stations. Forest fire hazards occurred in the spring season from the end of March to the middle of April. For the first step, the primitive surface of temperature and humidity was interpolated by IDW (the standard interpolation method). These thematic maps have a 1 km by 1 km grid spacing resolution. Next, we executed a simple regression analysis after extracting forest fire frequency, temperature and humidity values from 76 weather stations. The results produced a coefficient of determination ($R^2$) ranging from 0.4 to 0.6. Moreover, the estimation of forest fire occurrence hazards during early April was very high at Gyeongbuk Interior, Chungcheong Interior and part of Gangwon. The range of temperature and humidity having an influence on forest fire occurrence was as follows: average temperature and relative humidity in early April was $9-12^{\circ}C$ and 61-65%. At the end of March, temperature was $6-10^{\circ}C$, humidity 62-67%, and temperature was $11-14^{\circ}C$ and humidity 60-67% in the middle of April.

• Journal of Ginseng Research
• /
• v.6 no.1
• /
• pp.84-99
• /
• 1982

Water content and its seasonal change in reprodltctive organs were reviewed in relation to cultivation practice s. Precipitati on and humidity under shade roof were reviewed in relation to shading ,jystem and environmental factors. High water content of reproductive organs suggests vulnerability to water stress during reproductive growth stage. Watering during dehisconce treat menu seems to keep optimum temperature but cnoventional practice seems to be too often In watering. Information effe on water physiology of seeds is too rare to develop seed storing method and ctive seed use. Dehiscent mechanism was considered in terms of water absorption of embryo. Precipitation rate of conventional shade roof reaclled to 38% and at line level 50% and varied with shade patterns. Precipitation rate under shade has been investigated for itself but should be investigated in relation to light intensity and soil moisture content Relative humidity under shade depends mainly on air humidity and soil moisture, considerably on shade materials and lithe on pole height, bed width or plant density. Since relative humidity was lower in afternoon it was often less than 50% even in summer with high temperature suggesting possible disorder of phi biological function especially in photosynthesis. More information was needed on optimum humidity for productive physiological function of leaf.