• Journal of Ecology and Environment
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• 제46권3호
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• pp.161-171
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• 2022

Background: Epilobium hirsutum L. is designated as an endangered plant in South Korea located in Asia, due to the destruction of its habitats through the development of wetlands. Therefore, in this study, in order to find a light condition suitable for the growth and ecophysiological responses of Epilobium hirsutum L., those of this plant under treatment with various light qualities in a smart farm were measured. Results: In order to examine the changes in the physiological and growth responses of Epilobium hirsutum L. according to the light qualities, the treatment with light qualities of the smart farm was carried out using the red light: blue light irradiation time ratios of 1:1, 1:1/2, and 1:1/5 and a red light: blue light: white light irradiation time ratio of 1:1:1. As a result, the ecophysiological responses (difference between leaf temperature and atmospheric temperature, transpiration rate, net photosynthetic rate, intercellular CO₂ partial pressure, photosynthetic quantum efficiency) to light qualities appeared differently according to the treatments with light qualities. The increase in the blue light ratio increased the difference between the leaf temperature and the atmospheric temperature and the photosynthetic quantum efficiency and decreased the transpiration rate and the intercellular CO₂ partial pressure. On the other hand, the white light treatment increased the transpiration rate and intercellular CO₂ partial pressure and decreased the temperature difference between the leaf temperature and the ambient temperature and photosynthetic quantum efficiency. Conclusions: The light condition suitable for the propagation by the stolons, which are the propagules of Epilobium hirsutum L., in the smart farm, is red, blue and white mixed light with high net photosynthetic rates and low difference between leaf temperature and atmospheric temperature.

• Journal of Biosystems Engineering
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• 제37권5호
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• pp.296-301
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• 2012

Purpose: Combustion and fuel qualities of the animal-fats biodiesel as a heating fuel for agricultural hot air heater were studied. Methods: Biodiesel (BD) was made from animal-fats by reacting with methanol and potassium hydroxide in the laboratory. The biodiesel made in the laboratory was tested for fuel and combustion qualities. Results: The kinematic viscosity and the calorific values of the biodiesels were measured. Kerosene based biodiesel, BD20 (K) showed 18 cSt at $-20^{\circ}C$. It seemed that BD100 was not suitable for a heating fuel under some temperature. As BD content increased, the calorific value decreased up to 40,000 J/g for BD100, while the calorific value of light oil was 45,567 J/g showing difference of 5,567 J/g, about 12% difference. Several different fuels including BD20 (biodiesel 20% + light oil 80%), BD50 (biodiesel 50% + light oil 50%), BD100 (biodiesel 100%), and light oil were tested for fuel combustion qualities for agricultural hot air heater, and their combustion performances were compared and analyzed. Flame dimensions of biodiesels and light oils were almost the same shape at the same combustion condition. Generally, the $CO_2$ amounts of BDs were greater than light oil. However, in this study the differences were minor, so there was no significant difference existed between the BDs combustion and light oil. Conclusions: It seemed that quality was good for heating oil for agricultural hot air heater because of showing no barriers for continuous combustion and proper exhaust gas temperature and $CO_2$ amount discharged. But, for fuel fluidity for higher BD content fuel could be a detrimental problem in situations where the outdoor temperature is lowered. As BD content increased, calorific value decreased up to 40,000 J/g for BD100. Calorific value difference between BD20 and light oil was about 1,360 J/g.

• Journal of Plant Biology
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• 제33권3호
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• pp.203-210
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• 1990

Effects of blue and red light on photorespiration in the leaf disks of pea were studied. The rate of total 14CO2 fixation was more or less higher under red light than blue light irradiation of the same quantum (94.8 $\mu$Em-2.S-1/mV). The release of 14CO2 by photorespiration was more stimulated under blue than red light. Among the photorespiratory intermediates, 14C was more incorporated ito serine under blue light than red light. However, 14C was more incorporated into glycine under red light than blue light. The incorporation of 14C into glycolate was very low under both light qualities, but higher under red light than blue light. Among the enzymes related to photorespiration, only glycolate oxidase was activated and/or synthesized by blue light irradiation. Moreover, more 14C2 was released from glycoate-1-14C under blue light than red light irradiation, but 14C2 release from glyoxylate-1-14C and glycine-1-14C showed no difference by the either light qualities. These results suggest that blue light is more effective in the photorespiratory CO2 evolution than red light. The reason is considered that glycolate is easily metabolized under blue light due to the stimulation of the glycolate oxidase activity.

• 생물환경조절학회지
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• 제31권1호
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• pp.60-66
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• 2022

본 연구는 파프리카 육묘 시 다양한 LED 광질(red:blue = 10:0, 8:2, 2:8, white)에 따른 생육변화에 대하여 구명하여 수경재배용 묘 생산을 위한 전용육묘장의 기반기술로 활용하고자 수행하였다. 초장과 줄기직경의 생육은 red 비율이 높을수록 유의하게 길거나 굵었고, 엽면적은 LED red:blue = 8:2에서 가장 넓었다. 건물 중량도 엽면적과 동일한 경향이었다. LED white에서는 모든 묘의 소질에서 다른 처리들보다 뚜렷하게 저조하였다. 상대생장률은 red 비율이 높을수록 높은 경향을 나타내었고 순동화율은 blue 비율이 높을수록 높은 경향을 나타내었다. 따라서 본 시험에서 LED를 활용한 파프리카 육묘 시 초장, 엽면적, 단위엽면적당 건물생산능력 등을 고려하였을 때 혼합광을 이용하는 것이 적합하고 특히, LED red:blue = 8:2가 가장 적합한 것으로 생각된다. 그리고 red와 blue 파장의 적절한 혼합 비율을 통해 파프리카 묘의 초장 및 절간장을 제어할 수 있을 것으로 생각된다.

• Journal of Biosystems Engineering
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• 제33권2호
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• pp.124-129
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• 2008

In this study, fuel qualities including kinematic viscosity and pour point in the various temperature, calorific value and combustion characteristics of two biodiesels based on the soybean and waste oil blended with light oil were investigated and discussed in order to figure out to confirm fuel compatibility taking the place of light oil in the hot air heater or boiler. As biodiesel content ratio increased calorific value of biodiesel decreased, and the difference was 13% between 100%-biodiesel and light oil. In general, pour points of the biodiesels were higher than light oil, and as biodiesel content ratio increased pour point increased. About 15 cSt was the pour point of biodiesels and light oil, which occurred at 3 to $4^{\circ}C$ in the biodiesels and $-25^{\circ}C$ in the light oil. Flame dimensions of biodiesels and light oil were almost same at the same combustion condition in the burner of the hot air heater. CO concentrations in the exhaustion gas were far lower than those of the light oil. Though pour point of biodiesel is a little inferior to light oil, still biodiesel can be an alternative fuel substituting for light oil in combustion system without much modifying the current oil combustion mechanism.

• 한국환경농학회지
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• 제40권4호
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• pp.270-278
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• 2021

BACKGROUND: Horticultural plant growth under field and/or greenhouse conditions is affected by the climate changes (e.g., temperature, humidity, and rainfall). Therefore investigation of hydroponics on field horticultural crops is necessary for year-round production of the plants regardless of external environment changes under plant factory system with artificial light sources. METHODS AND RESULTS: Common sage (Salvia plebeia), nasturtium (Tropaeolum majus), and hooker chive (Allium hookeri) plants were hydroponically culturing in the plant factory with blue-red-white LEDs (Light-Emitting Diodes) and fluorescent lights (FLs). Leaf numbers of common sage under mixture LED and FL treatments were 134% and 98% greater, respectively than those in the greenhouse condition. In hooker chives, unfolded leaf numbers were 35% greater under the artificial lights and leaf elongation was inhibited by the conventional sunlight compared to the artificial light treatments. Absorption pattern of NO₃-N composition in hydroponic solution was not affected by the different light qualities. CONCLUSION(S): Plant factory system with different light qualities could be applied for fresh-leaf production of common sage, nasturtium, and hooker chive plants culturing under field and/or greenhouse. Controlled light qualities in the system resulted in significantly higher hydroponic growth of the plants comparing to conventional greenhouse condition in present.

• Journal of Biosystems Engineering
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• 제25권6호
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• pp.481-488
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• 2000

This study was initiated in order to find alternative fuel substituting for light oil the most common fuel for heating greenhouse. The tire oil used in this research was produced by pyrolysis process, one of the final products besides steel string and carbon black in which waste tires as a form of chopped pieces broken by shredding machine are heated up to 200~30$0^{\circ}C$ with maximum restraining of oxygen supply. In order to justify light oil equivalent qualities in tire oil combustion characteristics were defined in the way of comparing kinetic viscosities in the wide range of temperature flame sizes and exhaust gas components in the various combustion conditions. We found that kinetic viscosity of tire oil was lower than light oil by 1 to 2 cSt in the temperature range showing better flowing mobility in the fuel line of the burner and no significant difference in flame size between the two oils in the all combustion treatments. However much more NO and SO$_2$ were detected from the exhaust gases of tire oil than light oil combustions. In fact tire oil contains more nitrogen and total sulfur, by 25 times and 40 times respectively than light oil according to the composition analysis. Tolerable limit for SO$_2$discharge amount defined by the national air pollution standards is under 540ppm so tire oil combustion satisfies the requirement though. It is desirable if sulfur and nitrogen filtering process shall be added in the tire oil production line. Except the exhaust gas components all greenhouse heating qualities of tire oil including hot air temperature are very identical to those of light oil.

• Journal of Biosystems Engineering
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• 제27권4호
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• pp.335-340
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• 2002

Recently, in Korea, round bale wrapping silage made by fresh rice straw are partially utilized. The colors of stretch film using far wrapping the fresh rice straw round bale are white, green and black. The light transmittance of green and white color stretch film was not founded the difference. However, the light transmittance of black color stretch film was largely difference of two stretch films. This study was carried out to measure qualities of fresh rice straw wrapping silage by softening processing of fresh rice straw and colors effects of wrapping stretch film. The analyzed factors were the light transmittance of stretch film, variation of the temperature in fresh rice straw round bale and qualities of the silage in crude protein, ADF, NDF, organic acid, etc. It was difficult to find in this study the colors effects of stretch film on silage qualities by the silage wrapping. But, when make fresh rice straw wrapping silage, wrapping silage fermentation effect goes well more if handle softening the fresh rice straw.

• 한국버섯학회지
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• 제8권4호
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• pp.137-141
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• 2010

1. 광 종류별 조도는 백색광은 2,270Lux로 가장 밝았으며, 황색광 1,750Lux, 청색광 460Lux, 적색광 400Lux의 순이었다. 2. 자실체 특성을 조사한 결과, CBM-1757이 느티만가닥버섯에 비하여 갓의 크기와 대직경이 양호한 경향이었으며, 광 종류간에는 황색광에서 다른 광에 비하여 다소 좋은 경향이었다. 3. 생육기간은 CBM-1757이 느티만가닥버섯에 비하여 균 배양일수는 2일, 초발이소요일수는 1일, 생육일수는 1일정도 단축되어 생육기간이 8일 정도 빠른 경향이었다. 광종류간에는 황색광에서 생육기간이 70일 소요되어 다른 광에 비하여 2~4일 정도 단축되는 경향이었다. 4. 유효경수 및 개체중은 품종간에 차이가 나지 않는 경향이었고, 병당 수량은 느티만가닥버섯 94.8g에 비하여 CBM-1757은 95.6g으로 약간 많았다. 광 종류간에는 백색광의 96.0g에 비하여 청색광 및 적색광에서는 2~9%가 감소되었으나, 황색광에서는 103.4g으로 8% 정도 증수되는 경향이었다. 5. 버섯의 색도는 CBM-1757이 느티만가닥버섯에 비하여 명도, 적색도 및 황색도가 높았으며, 광 종류간에는 황색광에서 다른 광에 비하여 다소 높은 경향이었다.

• 항공우주시스템공학회지
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• 제8권3호
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• pp.20-26
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• 2014

This paper presents the procedures and the results of the pitch control force via flight test for a light airplane in order to make out the stability of the aircraft and the compliance with concerned regulation. The flight test procedures were determined in order to obtain the aircraft type certification. The instrumentation equipments including airspeed indicator, accelerometer, and pitch control force measurement tools are used to perform the flight test. For the flight test, the airspeed and the pitch control force with related normal acceleration are measured sustaining turn flight with bank angle derived from trim speed. The flight test results showed that the handling qualities of the airplane are complied with the KAS-23, the regulation of the Korean government for the light airplane type certification.