• Magazine of the Korea Concrete Institute
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• v.10 no.4
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• pp.205-212
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• 1998

Frost damage of a storage tank for chemical admixtures caused by a low temperature in winter and quality deterioration of chemical admixtures have been often reported. However, there have been few regulations and researches related to the frost damage of chemical admixtures and facilities. Therefore, this paper is intend to investigate not only, the freezing points of chemical admixtures such as AE admixtures and water-reducing AE admixtures, etc., but also the quality variation of concrete used with chemical admixtures before freezing and after freeze-thaw cycles. According to the results of experiments, most chemical admixtures except anti-freezing agent and accelerating water-reducing AE admixtures should be kept from being frozen in low winter temperatures. However, full agitation of frozen chemical admixtures dose not cause the problems of concrete related to the quality of chemical admixtures.

• Journal of the Korean GEO-environmental Society
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• v.20 no.4
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• pp.17-21
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• 2019

In the cold region, the frozen damages in highway tunnels and regular road tunnels have widely been investigated and reported, but the measurement has not been sufficient made. The average temperature in cold region is below the zero, resulting in that the damage due to freezing at the entrance/exit of tunnel is more severe than in the middle of tunnel. In this study, a heating element was developed to prevent the tunnel lining from being frozen by enforcing to increase the temperature of tunnel lining. Then field tests using the developed heating element were performed and it was ensured that the temperature of tunnel lining increased after a certain time.

• Journal of Bio-Environment Control
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• v.13 no.3
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• pp.162-166
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• 2004

Air temperature variation along the length of the air duct in an air-heated plastic greenhouse was large, 13 ～ 15$^{\circ}C$ between the front and the rear side of a greenhouse. To reduce this temperature variation, a new PE-film air duct having a small duct inside a large duct (double duct) was developed. This double duct was consisted of an inner duct with air outlets at a 0.15 m interval and an outer duct with air outlets at a 2.5 m interval. Diameters of the air outlet holes were 7, 15, and 35 cm from the front to the end of the inner duct film, while identical 10 cm holes were used on the outer duct film. As a result, air temperature was $46^{\circ}C$ at the beginning side and $47^{\circ}C$ at the ending side, while the conventional single duct had $53^{\circ}C$ at the beginning point and $38^{\circ}C$ at the ending point with a variation of $15^{\circ}C$. Height of a cucumber crop grown in a greenhouse with the new double air duct system was 65.5 cm, 14% increase as compared to that in a greenhouse with a conventional air duct system. Total fruit yield per l0a greenhouse in a greenhouse with the new double air duct system was 4,616 kg, which was 17% greater than that in a greenhouse with a conventional air duct system. Amount of heating oil consumption during March 3 to April 24, 2002 was 3,233 L per l0a greenhouse with the new double air duct system, which was 13% less than that with a conventional air duct system.

• Asian Journal of Turfgrass Science
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• v.23 no.2
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• pp.279-286
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• 2009

This study was carried out to utilize the waste heat from office building for turfgrass culture on a roof garden. Heating system had been installed in the middle of soil profile on the turf areas in the garden plots. The results showed that the installation of heating system increased the shoot density, turfgrass quality, coverage rate, and root length compared with the control plots. The surface temperature of heating plots reached at $10.9^{\circ}C$ when the control plot showed $0^{\circ}C$, however, the soil moisture content was decreased 1.9% by the heating system. When the height of the snow accumulation reached over a 15cm, the it took only 4 days to melt out completely, while the height did not changed those period at the control plots. When the water temperature in boiler increased to $60^{\circ}C$ from a proper temperature of $55^{\circ}C$ in turf growth, the desiccation from leaf tip was started to occur caused by drought stress. More detail research should be followed in stress physiology in turf management in roof garden operation.

• Korean Journal of Poultry Science
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• v.8 no.1
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• pp.7-14
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• 1981

The experiment using Anake broiler strain chicks was conducted to study the effort fungistatic agents on microbial counts, Ins of nutrient, growth rate and feed efficiency of the broiler. Feed was adjusted to 12% and 15% moisture level during hot and high humidity season and sorbic acid at the level of 0.02%, 0.04% and Ca-propionic acid at the level 0.1% 0.2% was added. The results obtained were as follows. 1, The Addition of fungistatic agents could slightly reduce mold and yeast counts. The highest effect on inhibition of mold and yeast counts was observed for the addition of sorbic acid at 0.04% level to the fled contained 15% moisture. 2, Approximately 14% starch loss of ground corn was observed from the fred contained 15% moisture and the loss could be diminished to 3-7% by the addition of fungistatic agents with the superior effect of sorbic acid to Ca-propionic acid. 3. Approximately 15% fat loss was detected when high moisture fled was und and this was reduced to 7% by the addition of 0.04% sorbic acid to the feed. 4. Significantly higher growth rate (p＜0.05) during starter period was observed for low moisture feed added by sorbic acid compared with that for high moisture diet without fungistatic agents or with Ca-propionate at the level of 0.1%. 5. Significantly lower feed efficiency (p＜0.05) during starter period of high moisture feed without fungistatic agents was observed; hower no significant different response was detected by either moisturer level of kinds and levels of fungistatic agents used. 6. Significantly higher growth rate (p＜0.05) during finisher period of lower moisture feed with 0.04% sorbic acid was observed compared with that of high moisture fled without fungistatic agents or the feed added by 0.1% Ca-propionate level. 7. Significantly higher feed efficiency (p＜0.05) during finisher period of low moisture feed added by sorbic acid 0.02% or 0.04% level was found compared with that of high moisture feed without fungistatic agents and low moisture feed added by Ca-propionate at the level of 0.1% or 0.2%. 8. Mort bacteria, mold and yeast were observed in the ceca than in small intestine. The. moisture content of dict had no effect on intestinal microfloral counts. However, numbers of mold and yeast of intestine could slightly be reduced by fungistatic agents administration. 9. Nothing but encephalomalacia to chicks fed feed contained 15% moisture without addition of fungistatic agents was observed. In conclusion, addition of either sorbid acid at 0.04% level and Ca-propionate at 0.2% level to high moisture feed or reduced moisture level to 12% could be con-sidered more effective to enhance growth rate and fled efficiency of broilers during summer period.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.2
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• pp.60-67
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• 2017

The purpose of this study was to evaluate the influence of landscaping shade materials' porosity on the Mean Radiant Temperature (MRT) of summer outdoors. The MRTs were measured under seven different types of black membranes with holes of 8mm diameter at different intervals applied on the top of wooden boxes, and compared with those of four additional control plots with or without shade and lateral boxes. The applied porosities were 0.5, 1, 2, 4, 8, 16%, and 32%, and three groups of three shades were compared sequentially from August 13 to September 8, 2016. The MRTs under the shade without lateral block, no shade with lateral block, and shade with lateral block were $33.08^{\circ}C$, $45.80^{\circ}C$, and $42.3^{\circ}C$, respectively, while that of no-shaded no-lateral screen was $44.26^{\circ}C$, based on records from 11:00 AM to 3:00 PM on the days with a peak globe temperature higher than $30^{\circ}C$. An ANCOVA analysis showed that the MRTs under the shades with 0.5, 1, 2, 4, 8, 16%, and 32% porosities were calculated as 43.40, 43.10, 41.49, 40.43, 39.61, $37.91^{\circ}C$, and $38.12^{\circ}C$, respectively, while that in the no shaded control box was $45.8^{\circ}C$. The curve fitted between MRTs and the porosity showed a U-shaped quadratic function with the minimum MRT at 16% practically or 22.5% statistically.

• Journal of Bio-Environment Control
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• v.25 no.4
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• pp.302-307
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• 2016

The aim of this study was to examine the optimum wattage and installation height using nano-carbon fiber infrared heating lamp (NCFIHL) for heating energy saving and plug seedling production in plug seedling production greenhouse in winter season. NCFIHL of 700 and 900 W was installed over the bed ($1.2{\times}2.4m$) as 0.7, 1.0, and 1.3 m height, respectively, for the production of grafted watermelon seedling in venlo-type glasshouse. Watermelon (Citrullus lanatus (Thunb.) Manst.) 'Jijonggul' and gourd (Lagenaria leucantha Rusby.) 'Sunbongjang' were used as scions and rootstocks, respectively. The scions and rootstocks were grafted by single cotyledon ordinary splice grafting. Light intensity of NCFIHL was below the $1{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ in all treatment. Spectral distributions of NCFIHL presented mostly infrared area. When outside air temperature was below $10^{\circ}C$, 700 and 900 W NCFIHL installed with 0.7 m height treatment and 900 W NCFIHL installed with 1.0 m height treatment maintained the setting air temperature ($20^{\circ}C$) at night. In the result of taking thermal imaging, the grafted watermelons were getting warm fast in 900 W NCFIHL installed with 0.7 m height treatment at night. Compactness of the grafted watermelons was the greatest in 700 W NCFIHL installed with 1.3 m height treatment. The results indicate that NCFIHL installed above 1.0 m height using 700 W was suitable for production of plug seedling.

• Korean Journal of Agricultural Science
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• v.6 no.1
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• pp.56-64
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• 1979

Two types of fiat-plate collector were designed and constructed for utilizing the solar energy as heating source of red pepper drying. It was performed to investigate the basic factors on using the collectors and the drying effect on various types of red pepper, and the results obtained are summarized as follows. 1. The optimum tilted angles of the collector in Daejeon area were ${\phi}-15^{\circ}$ in summer season and ${\phi}+15^{\circ}$ in winter season when it was adjusted two times per a year: 2. In the conditions during experiment period, average atmospheric temperature and relative humidity were $25.6^{\circ}C$ and 52.6%, respectively, and $42.0^{\circ}C$, 74.2% in the control chamber. The temperature in the drying chamber connected to the water heater was the highest but relative humidity in the chamber connected to the air heater was the lowest among the chambers. 3. The drying velocity of whole red pepper in the chamber connected to the water heater was the fastest as 2.3 times as compared to the whole type on the mat drying followed by air heater and control in decreasing order. The horizontally cut red pepper in the chamber connected to the water heater was dried exceedingly fast among twelve plots. 4. The content of capsaicine as pungent principle and of capsanthine as red pigment in the red pepper were reduced during drying but there were no differences significantly on the drying method, and it could not affect much on the quality of dried product.

• Asian Journal of Turfgrass Science
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• v.21 no.1
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• pp.23-37
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• 2007

This study was carried out to investigate the characteristics of root growth in Kentucky bluegrass sod(KBS) and creeping bentgrass sod(BGS) transplanted in summer(August 9) and fall(September 19), respectively. Hydroponic system was also used to observe rooting development in the study. Root development differed in KBS by transplanting time. It reached to more than 5 cm after 100 days In summer and 50 days in fall. However, BGS's root grew over 6cm after 40 days, regardless of the season. There was no significant differences in BGS, regardless of any cutting treatment. In the case of KBS, it was best with sod culled with 0.5cm deep and 1.5cm long. But it grew beyond 5 cm in root growth under any treatment after 40 days in transplanting. In a hydroponic study, BGS produced root over 100cm for 80 days through a summer season. However, the root of KBS did only grow in condition below $20^{\circ}C$. These results indicated that root growth characteristics were variable in BGS and KBS. It was considered that rooting development of BGS might be improved with sufficient irrigation in summer, and KBS grows well in lower temperature of $10{\sim}18^{\circ}C$, as compared with BGS. As to establishing the lawn with a sodding method, it should be careful in transplanting time, especially KBS.

• Korean Journal of Medicinal Crop Science
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• v.13 no.4
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• pp.186-189
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• 2005

Plant flowering should be mainly affected by temperature and daylength. The study was carried out to measure the effect of temperature during winter on growth and floret flowering of Orostachys japonicus grown under 2 hour night break. Temperature was controlled above $10^{\circ}C$ and $20^{\circ}C$ as heating boilers were run below them to compare the natural temperature. Night-break treatment was done on August 25 and afterward samples were taken every 4 weeks to check growth, morphological and flowering related characters. Plant height, inflorescence length, number of leaves including bracts and stem diameter were increased in heating temperatures of > $10^{\circ}C$ compared to natural temperature although similar in the two heating ones. Leaves and bracts, florets, stem, root, shoot and total dry weights showed the same response as the above morphological and flowering related characters. Florets were more formed but less flowered with higher temperatures. Anthesis rates of individual plant were 100% in natural temperature, 25% in > $10^{\circ}C$ heating temperature but none in > $20^{\circ}C$ heating temperature.