• Title/Summary/Keyword: Dew

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An Experimental Study on Radiation/Convection Hybrid Air-Conditioner (복사-대류 겸용 하이브리드 냉방기에 대한 실험 연구)

  • Kim, Nae-Hyun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.6
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    • pp.288-296
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    • 2019
  • Radiation cooling has used ceilings or floors as cooling surfaces. In such cases, to avoid moisture condensation on the surface, the surface temperature needs be higher than the dew point temperature or an additional dehumidifier is added. In this study, with a goal for residential application, intentional moisture condensation on the cooling surface was attempted, which increased the cooling capacity and improved the indoor comfortness. This method included two separate refrigeration cycles - convection-type dehumidifying cycle and the panel cooling cycle. Test results on the panel cooling cycle showed that, at the standard outdoor ($35^{\circ}C/24^{\circ}C$) and indoor ($27^{\circ}C/19.5^{\circ}C$) condition, the refrigerant flow rate was 8.8 kg/h, condensation temperature was $51^{\circ}C$, evaporation temperature was $8.8^{\circ}C$, cooling capacity was 376 W and COP was 1.75. Furthermore, the panel temperature was uniform within $1^{\circ}C$ (between $13^{\circ}C$ and $14^{\circ}C$). As the relative humidity decreased, the cooling capacity decreased. However, the power consumption remained approximately constant. In the convection-type dehumidification cycle, the refrigerant flow rate was 21.1 kg/h, condensation temperature was $61^{\circ}C$, evaporation temperature was $5.0^{\circ}C$, cooling capacity was 949 W and COP was 2.11 at the standard air condition. When both the radiation panel cooling and the dehumidification cycle operated simultaneously, the cooling capacity of the radiation panel cycle was 333 W and that of the dehumidification cycle was 894 W, and the COP was 1.89. As the fan flow rate decreased, both the cooling capacity of the radiation panel and the dehumidification cycle decreased, with that of the dehumidification cycle decreasing at a higher rate. Finally, a possible control logic depending on the change of the cooling load was proposed based on the results of the present study.

The Comparison between "the Book of Etiquette and Ceremonial" and the Hundred Schools of the Contents about Funeral Rites (『의례』와 선진 제자서의 상례 비교)

  • Yun, Muhak
    • The Journal of Korean Philosophical History
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    • no.59
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    • pp.215-240
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    • 2018
  • In this paper, the contents about funeral rites in "the Book of Etiquette and Ceremonial"(儀禮) were compared to those in the books of Hundred Schools of Thought. The most direct and systematic document related to funeral rites is "the Book of Etiquette and Ceremonial". Some of its contents had been reflected in the books of Hundred Schools of Thought, such as "Zuo Zhuan", "Mozi" and "Xunzi", while others didn't agree with one another. It happened because some contents had been already reflected in the books of Hundred Schools of Thought in the process of establishing scriptures about manners including the ancient "Book of Etiquette and Ceremonial", and because, on the contrary, the contents of the books of Hundred Schools of Thought had become included in the scriptures about manners by following Confucianism. First, the basic contents of Chapter 'Mourning Clothes' in "the Book of Etiquette and Ceremonial" were generally reflected in the books of Hundred Schools of Thought, and there are many contents in common. Most prominently, three-year-mourning for parents and a king had been enhanced in Confucianism commonly. Although Mohism opposed Confucian luxurious and long funerals (厚葬久喪), the mourning clothing system in "the Book of Etiquette and Ceremonial" can be said to have been people's universal understanding until the Spring and Autumn period at least. In addition, it has been verified that there were differences in the mourning clothes depending on the one who wore them was an adult or not both in "the Book of Etiquette and Ceremonial" and the books of Hundred Schools of Thought. On the other hand, many arguments in the contents about funeral rites reflected in the books of Hundred Schools of Thought were different from the rules in "the Book of Etiquette and Ceremonial". In particular, the mourning clothes for parents reflected in the books of Hundred Schools of Thought showed that there were differences depending on social positions, which was dissimilar to the regulations in "the Book of Etiquette and Ceremonial". Also, different from the mourning clothes system for parents and a king, the system for a wife and a concubine was dissimilar to the rules in "the Book of Etiquette and Ceremonial" in many ways. Since the regulations of Chapter of 'Mourning Clothes' in the present version of "the Book of Etiquette and Ceremonial" suggest different mourning clothes and periods depending on who wears the mourning clothes and what social position the deceased had, it seems difficult to implement them strictly historically as well as at those times. Especially, while the funeral rituals for a child was relatively clear based on the parent-child relationship of "affection" and those for a king and parents were plainly regulated and emphasized, the rules of those for a vassal and a wife were absent or ambiguous in many cases. Therefore, the term of "the Theee Bonds"(三綱) appeared first in Dong Zhongshu(董仲舒)'s "Luxuriant Dew of the Spring and Autumn Annals"(春秋繁露) that reflected the ideology of political ethics of Han Dynasty(漢代), but regarding its contents, it can be said to have been already reflected in "the Book of Etiquette and Ceremonial".

Forecasting Leaf Mold and Gray Leaf Spot Incidence in Tomato and Fungicide Spray Scheduling (토마토 재배에서 점무늬병 및 잎곰팡이병 발생 예측 및 방제력 연구)

  • Lee, Mun Haeng
    • Journal of Bio-Environment Control
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    • v.31 no.4
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    • pp.376-383
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    • 2022
  • The current study, which consisted of two independent studies (laboratory and greenhouse), was carried out to project the hypothesis fungi-spray scheduling for leaf mold and gray leaf spot in tomato, as well as to evaluate the effect of temperature and leaf wet duration on the effectiveness of different fungicides against these diseases. In the first experiment, tomato leaves were infected with 1 × 104 conidia·mL-1 and put in a dew chamber for 0 to 18 hours at 10 to 25℃ (Fulvia fulva) and 10 to 30℃ (Stemphylium lycopersici). In farm study, tomato plants were treated for 240 hours with diluted (1,000 times) 30% trimidazole, 50% polyoxin B, and 40% iminoctadine tris (Belkut) for protection of leaf mold, and 10% etridiazole + 55% thiophanate-methyl (Gajiran), and 15% tribasic copper sulfate (Sebinna) for protection of gray leaf spot. In laboratory test, leaf condensation on the leaves of tomato plants were emerged after 9 hrs. of incubation. In conclusion, the incidence degree of leaf mold and gray leaf spot disease on tomato plants shows that it is very closely related to formation of leaf condensation, therefore the incidence of leaf mold was greater at 20 and 15℃, while 25 and 20℃ enhanced the incidence of gray leaf spot. The incidence of leaf mold and gray leaf spot developed 20 days after inoculation, and the latency period was estimated to be 14-15 days. Trihumin fungicide had the maximum effectiveness up to 168 hours of fungicides at 12 hours of wet duration in leaf mold, whereas Gajiran fungicide had the highest control (93%) against gray leaf spot up to 144 hours. All the chemicals showed an around 30-50% decrease in effectiveness after 240 hours of treatment. The model predictions in present study could be help in timely, effective and ecofriendly management of leaf mold disease in tomato.

Development of heat exchanger by the utilization of underground water. I - Design for plat fin tube - (지하수 이용을 위한 열교환기 개발. I - 냉각핀의 설계제작 -)

  • Lee, W.Y.;Ahn, D.H.;Kim, S.C.;Park, W.P.;Kang, Y.G.;Kim, S.B.
    • Journal of Practical Agriculture & Fisheries Research
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    • v.4 no.1
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    • pp.119-127
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    • 2002
  • This study was conducted to develop the heat exchanger by utilizing the heat energy of underground water(15℃), which might be used for cooling and heating system of the agricultural facilities. We developed the heat exchanger, parallel type plat fin tube made of Aluminum(Al 6063), which was named Aloo-Heat(No. of The registration design : 0247164, by Korean Intellectual property Office). The fin of exchanger was design of the granulated surface for minimizing fouling factor and dew forms, and also placed parallel to the tube in order to minimized the resistance of flows. 1. Aloo-heat was designed to have 0.03m for inside diameter, 0.036m for outside diameter of tube, 0.0012m for thickness of fin and 0.032m for length of plat fin. 2. t was also designed to have 1.5248m2/m for outside area of heat transfer, 0.0942m2/m for inside area contacting hot liquid, and the ratio (Ra) was 16.1869. 3. Efficiency of the fin was 93 percentage when fin length was 0.032m, and the fin thickness satisfied equation $\frac{h{\rho}}{k}$< 0.2 when it was 0.0012m. 4. According to the performance test of Aloo-heat, as the temperature and rate increased, the heating value also increased, heating value was 504kJ/h·m and 6,048kJ/h·m when it was 60℃, 10 𝑙/min and 80℃, 40 𝑙/min respectively. 5. The test of heating value was confident, because correlation value(R2) was 0.9898 for the temperature and 0.9721 for flow rate of hot liquid, respectively.