• Journal of Bio-Environment Control
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• v.14 no.4
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• pp.245-253
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• 2005

This study was carried out to determine the optimum EC supply by accumulation amount of solar radiation in closed system. EC concentration of drainage was higher than that of supply. The higher EC concentration of supply was, the lower pH of drainage was. It was no difference in the quality of cut rose 'Nobles' (Rosa hybrida), stem length, stem diameter, leaf number, petal length, and petal diameter by EC treatment by season. The yield was higher about $6\%$ in treatment of EC $1.3dS{\cdot}m^{-1}$ in April and May, about $10\%$ in treatment of EC $10dS{\cdot}m^{-1}$ in June, July and August, and about $10\%$ in treatment of EC 1.0 or $1.3dS{\cdot}m^{-1}$ in September and October than the others. In general, the yield of the cut rose was higher in treatment of (B) EC 1.3 mS/cm in spring, EC $1.0dS{\cdot}m^{-1}$ in summer, EC $1.3dS{\cdot}m^{-1}$ in autumn, and EC$1.6dS{\cdot}m^{-1}$ in winter.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2002.11a
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• pp.69-85
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• 2002

최근들어 수경재배 생산물의 품질을 높이려는 연구와 시도가 많이 이루어지고 있는데 주로 과채류의 경우는 급액되는 양액농도의 변화, 미생물제재나 식물추출물(스테비아 등 고당도식물)의 엽면살포 또는 관주처리, 키토산, 목초액, 죽초액 등 신물질의 투입 등으로 다양하게 처리되고 있으며, 상당한 효과가 있는 것으로 알려진다. (중략)

• Korean Journal of Food Science and Technology
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• v.23 no.4
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• pp.437-441
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• 1991

During the evaporation of garlic juice by centrifugal thin film evaporator (Centri-Therm, CT-1B), the effect of feeding rate was investigated for its operation properties. On the process condition of feeding rate of 25 to 125 kg/h, theoretical average thickness of the garlic juice film on the rotating cone and residence time of the juice in the evaporator varied in the range of 0.52 to 0.89 mm and 1.77 to 6.75 second, respectively. And the flow of garlic juice was considered as a streamline flow by Reynolds number. At constant temperatures of steam and juice evaporation, concentration ratio decreased with the increase of the feeding rate. But the evapoartion rate and overall heat transfer coefficient increased with the increase of the feeding rate until the feeding rate reached a certain value and then decreased. On the conditions of $25{\leq}$feeding rate ${\leq}125\;kg/h$, evaporation temperature of $40^{\circ}C$, $95{\leq}steam$ $temperature≤120^{\circ}C$ and initial feed concentration of $32^{\circ}Brix$, concentration ratio and overall heat transfer coefficient were $1.04{\sim}2.04\;and\;3,074.33{\sim}17,614.70kJ/m^{2}{\cdot}h{\cdot}^{\circ}C$.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 1999.11a
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• pp.157-160
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• 1999

토양양액재배의 역사는 국내에서 '95년 이후 일부 시험기관에서 시험되었으며 일본과 이스라엘의 경우 꾸준히 연구가 수행되어 지금은 상당한 수준에 이르고 있다(이, 1999 ; 서, 1999 ; 임, 1998). 일본에서는 양액토경재배가 강부(1994)에 의해서 그 기술이 연구되고 또한 일부 회사에서 저단가로 실용적인 시스템과 전용액비를 개발하여 보급하고 있다. 절화국의 경우에는 EC 1.0과 EC 1.5dS/m 처리구에서 생장과 품질이 양호하였으며 EC 2.0과 EC 2.5dS/m 처리구에서 생육 후반기 염류장해로 인한 뿌리 손상이 발견되었으며 초장과 품질이 저하하였다. (중략)

• Journal of Bio-Environment Control
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• v.21 no.1
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• pp.39-44
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• 2012

In the present study, it was performed that the influences of temperatures and electrical conductivity on the mycelial growth and formation of zoosporangium of the $Phytophthora$ sp. in paprika nutriculture. We investigated mycelial growth of $Phytophthora$ sp. at different temperatures. Morphological characteristics of the isolated pathogen from paprika were typically similar to those of $Phytophthora$ sp. such as no septa and formation of zoosporangia. Optimum growth temperature of the pathogen was $25^{\circ}C$. At $20^{\circ}C$, $30^{\circ}C$ and $15^{\circ}C$, the mycelium growth deceased, respectively. EC level of nutrient solution the mycelial growth was increased EC 0.5 up to $1.5dS{\cdot}m^{-1}$ and reduced 2.0 up to $3.5dS{\cdot}m^{-1}$. The formation of sporangia was negatively correlated with EC, and the formation of sporangia were highly inhibited at EC $4dS{\cdot}m^{-1}$.

• Korean Journal of Food Science and Technology
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• v.22 no.4
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• pp.479-485
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• 1990

For the automation of a evaporation process, computer based evaporation system was built and applied to acquisition of the process variables with an centrifugal thin film evaporator(Centri-Therm, CT-1B). Controls of the process conditions were performed by computer system for pressure, feeding rate, steam, evaporation temperature and flow rate of cooling water. The data acquisitions were also performed by computer system for the changes in the concentration and temperature readings for steam, evaporation and cooling water at the both inlet and outlet. The control and the acquisition variables were collected through the interface device and analyzed by programs using the PASCAL language. To control the feeding rate during the concentration process, inverter was used. The cooling water for the vapor condensation was controlled by the valve controller and should be supplied with the flow rate of 125 kg/h. The maximum vapor condensation rate was 41.7kg/h at the feeding rate of 125 kg/h.

• KSBB Journal
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• v.11 no.5
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• pp.529-535
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• 1996

Methyl frucloside was purified from the aqueous sugar/methyl fructoside solution by liquid chromatography using Amberlite IRA-900, strong anion-exchange resin. The optimum operating conditions, resolution and productivity of methyl fructoside were discussed to evaluate the practical feasibility of the proposed chromatographic separation process of methyl fructoside which is useful as a new starting material for sugar ester synthesis. The linear chromatography model with HETP was well applied to the chromatographic separation process of methyl fructoside and the theoretical solution successfully predicted the elution chromatogram of methyl fructoside and sucrose at different superficial linear velocity of eluent for rectangular feed with different loading volume of packed bed. The optimum operating conditions were found to be 75% with the loading volume of packed bed at 1.13 cm/min of the superficial linear velocity at $60^{\circ}C$, and gave the productivity of methyl fructoside of 7 mg/g-resin/h with the resolution of 1.1.

• Journal of Bio-Environment Control
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• v.13 no.3
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• pp.167-171
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• 2004

Objective of this research was to investigate the effect of irrigation concentration on the growth and fruit quality of sweet pepper(Capsicum annuum L.) in fertigation. The sweet pepper was grown for 210 days with irrigation concentration of EC 0.5, 1.0, 1.5, 2.0, and 3.0 dSㆍ$m^{-1 }$ in fertigation nutrient solution developed by European Vegetable R & D Center, Belgium. The net $CO_2$ assimilation and transpiration rate were the highest in the treatment of 2.0 dSㆍ$m^{-1 }$. The pH in the soil was range of 5.63 ～6.03, the EC increased as the irrigation concentration was getting higher. The SPAD value also increased as the irrigation concentration was getting higher, N, P, K, Mg except Ca were highest in the treatment of EC 2.0 dSㆍ$m^{-1 }$. The growth was good in the treatment of EC 2.0 dSㆍm$m^{-1 }$. The fruit length, width, firmness, and pericarp thickness had no statistical differences among treatments, the fruit fresh weight and dry weight were good in the treatment of EC 2.0 dSㆍ$m^{-1 }$ the yield was good in the treatment of EC 1.5 dSㆍ$m^{-1 }$ and EC 2.0 dSㆍ$m^{-1 }$ The sugar contents was the highest in the treatment of EC 2.0 dSㆍ$m^{-1 }$ with 9.0$^{\circ}$Brix. In conclusion, the optimal irrigation concentration for sweet pepper fertigation was EC 2.0 dSㆍm$^{-1}$ .

• Journal of Bio-Environment Control
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• v.25 no.2
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• pp.89-94
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• 2016

This study was conducted to determine the optimum nutrient solution, pH, irrigation interval, light intensity and planting density to growth of common ice plant (Mesembryanthemum crystallinum L.) in a closed-type plant production system. Three-band radiation type fluorescent lamps with a 12-h photoperiod were used. Nutrient film technique systems with three layers were used for the plant growth system. Environmental conditions, such as air temperature, relative humidity and $CO_2$ concentration were controlled by an ON/OFF operation. Treatments were comparison of the nutrient solution of Horticultural Experiment Station in Japan (NHES) and the nutrient solution of Jeju National University (NJNU), pH 6.0 and 7.0, irrigation interval 5 min and 10 min, light intensity 90 and $180{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, and within-row spacing 10 cm, 15 cm, 20 cm and 25 cm with between-row spacing 15 cm. Optimum macronutrients were composed N 7.65, P 0.65, K 4.0, Ca 1.6 and Mg $1.0mM{\cdot}L^{-1}$. There were no significant interactions between pH 6.0 and 7.0 about shoot fresh weight and shoot dry weight of common ice plant. Irrigation interval 5 min and 10 min was also the same result. Shoot fresh weight and shoot dry weight were highest at $180{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. Shoot fresh weight and shoot dry weight were decreased according to increasing the planting density. From the above results, we concluded that optimum nutrient solution, optimum levels of pH, irrigation interval, light intensity and planting density were 6.0-7.0 and 10 min, $180{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and $15{\times}15cm$, respectively for growth of common ice plant in a closed-type plant production system.

• Journal of agriculture & life science
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• v.53 no.1
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• pp.13-21
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• 2019

This study was carried out to acquire basic data for a long-term hydroponic culture through investigating water and inorganic ion uptake characteristics at different EC level of nutrient solution of three tomato varieties. Three different tomato varieties, the European type(cv. Daphnis), the Asian type(cv. Super Doterang) and cherry type(cv. Minichal), were used for the investigation. Also, the deep flow technique(DFT) was applied. The three different electrical conductivity(EC) level(1.0, 2.0, 3.0, and 4.0 dS·m-1) of hydroponic nutrient solution were used as variable. At a high EC level of nutrient solution, the leaf area and fresh weight decreased in the early stage, and its growth(plant height, leaf number, leaf area, fresh-weight) was poor with salt stress. Result showed that the higher the EC level of the nutrient solution, the lesser was water uptake. The water uptake was not significantly different from varieties in the first survey, but In the second survey, the 'Daphnis' did not show a significant decrease in water uptake in the EC level higher than 2.0 dS·m-1., on the other hand, 'Super Doterang' presented very low water uptake. At a low EC level, N, P, and K, were absorbed more than the concentration of the irrigation water, while Ca, Mg, S uptake were low. At a high EC level, almost ions absorbed less than 50% of the initial concentration of irrigation water. Thus, imbalance among ions was severe at low EC level compared to high EC level. 'Daphnis' was a variety that effectively utilize nutrients under nutrient stress, showing high absorption at low concentration condition and low absorption at high concentration condition. However, 'Daphnis' suffered most seriously by absorbing nutrients excessively.