• Journal of Biosystems Engineering
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• v.14 no.2
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• pp.128-136
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• 1989

The purpose of this study was to develop a computer operated automatic drip irrigation system for application in vinyl-house cultivation. The results can be summarized as follows: 1) The T-type ice compensation wire was used to measure the temperature. The voltage level measured up to 0.02 volt was used as input to an 8-bit A/D converter. 2) A specially devised tensiometer was used to content the watering system. When the needle of the pressure gauge reaches the lower threshold position it turns on the pumping system and turns off when it reaches higher threshold position. 3) In order to use the multiple gypsum blocks for one transducer, reed relays and a D/O board were used to make the sequential switching possible. 4) It was possible to automate the trickle irrigation system for the whole growth period of vinyl-house crops with the help of microcomputer. 5) In terms of furrow irrigation, the irrigation water consumption was the smallest, 2.8 times less than conventional method of surface trickle irrigation, 3.4 times less than subsurface trickle irrigation method. 6) In terms of productivity of cucumber, there was a drop in productivity when compared to furrow irrigation method, 7.2% for surface trickle irrigation, 27.4% for subsurface irrigation method.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.905-913
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• 2008

The water resource depending on mostly surface water has many problems, such as contaminated and unpredicted contamination event. For this reason, it has been employed highly technical treatment method for them, such as ground water dam and river bank filtration. it has been developed the radial collector wells in kind of bank filtration to increase efficiency for in-taking the water resource insead of the vertical well needed many wells to take more resource. But it has many problems with the incumbent method to bore the horizontal hole for radial collector wells, such as filling with the filter material outside of a strainer by watering, jamming as retrieving the casing tube with the filter material, eccentric boring etc. To reduce the problems of incumbent equipment, it has been developed the horizontal boring equipment and performed the field trial tests several times, which have bits and water jetting system with rotating the cone-shaped front to be excavated easily. In this paper, it was compared the brand-new with the incumbent non-rotating pressing insertion method. Also it was shown the problems of the incumbent method was reduced effectively.

• The Korean Journal of Pesticide Science
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• v.9 no.4
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• pp.374-379
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• 2005

Sublethal dose effect of imidacloprid on green peach aphid (Myzus persicae) was investigated. Nymphs of green peach aphid newly produced were counted on 4 days after sub-lethal dose treatment of imidacloprid. Numbers of nymph were not significantly different between $LC_1$ treatment and untreated control. Their numbers of nymph were 8.8 and 12.7 at $LC_1$ and untreated control, respectively. When they were tented at $LC_{10}$, $LC_{30}$ and $LC_{50}$. their numbers of newly produced nymph were 6.0, 5.1 and 3.9 and reduction rates were 52.7%, 59.8% and 69.3% at each treatment compare to untreated control. Reduction rates of newly laid nymph were proportional to the concentrations of imidacloprid treated. Repellent effect of aphid to imidacloprid was bigger in dipping than in watering method. Secretion amount had negative correlation with imidacloprid concentration in dipping method and suppression of secretion went up to 96%. In watering method, amount of secretion did not show any difference between insecticide concentration, but suppression, compared to untreated control, was over 97%.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.365-366
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• 2009

Humidity curing of the concrete after placing is significant to ensure the crack resistance, strength, and durability. Generally, there are watering and sheet curing methods as humidity curing methods to the upper part of slab concrete, therefore this study investigates effects of these curing methods to preservation of humidity on the cement mortar.

• Agricultural and Biosystems Engineering
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• v.5 no.2
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• pp.50-54
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• 2004

The study aimed to develop a mechanized mushroom growing system for the substrate materials mixing and wetting, materials fermentation and pasteurisation through the design of integrated cultivation machine system for oyster mushroom. The power requirement of the prototype during fermentation operation was measured in the range of 31$\~$33 kg-m and the torque has not so much differ by the kinds and quantity of materials. The work efficiency of conventional method for stacking the heap and turning the heap of cotton waste by tractor rotavator and manual wetting required 78 hours. But the watering, fermentation and sterilisation by the prototype use same operation required 25.5 hours, which can save the operation labour by $67\%$. The machine can be saved the requirement of heating energy by $63\%$, and the machine can also be saved the material cost by $44\%$. It is envisaged that the machine can effectively be used for large mushroom growing farms or joint use mushroom growing group-farmers in a village.

• Journal of the Korean Society of Visualization
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• v.20 no.3
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• pp.117-127
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• 2022

The present study has investigated the performance of hydrogen gas generators for inhalation purposes based on polyelectrolyte membrane water electrolysis (PEMWE). The system applied two watering methods. One is pumped water (pumping system) and the other is gravity-fed water without a pump (non-pumping system). The cell efficiencies were compared by measuring the cell voltage and temperature in the hydrogen gas generator, respectively. The results show that the cell voltage and temperature increase with the cell current. The cell temperature is lower in the pumping system than that in the non-pumping system at a given cell current. Even though the amount of hydrogen production is the same regardless of the pumping system, the cell efficiency of the hydrogen gas generator in the non-pumping system is better than that in the pumping system.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09c
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• pp.81-85
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• 2010

The medicinal plant, Kanzo (Glycyrrhiza uralensis), mainly grows on arid lands. The root of Kanzo has been compounded about 70% of herbal medicines in Japan because it has an important medicinal element. In addition, in recent years, the expansion of desertification becomes a serious problem. The cause is chiefly man activity such as over gathering plants1). The aim of this study is to prevent desertification by cultivating Kanzo with high quality. The first step is to grow Kanzo for greening. The second step is to stably produce the root with high medicinal quality. This paper presents growth properties of cultivating Kanzo by bottom watering method, which is under constant groundwater level. The main results of this paper are as follows: (1) The lower water content of cultivating soil is, the longer the root length is, (2) Growth of Kanzo is influenced by soil types, (3) Thick primary roots grow directly and vertically in low water content. On the other hand, thin secondary roots grow curvedly and horizontally in high water content and (4) Measuring evapo-transpiration velocity is the effective method to evaluate roots' growth tendency in the field.

• Magazine of the Korean Society of Agricultural Engineers
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• v.16 no.2
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• pp.3420-3429
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• 1974

This study was performed to estimate the daily water consumption for watering livestock and home use, and to organize the water systems in the rural districts of Korea. For these purposes, 560 farms and other 40 urban families were randomly chosen and investigated about their water systems and daily water consumption seasonally from July 20 to August 31, 1973, and other 82 livestock raisers' useful data for watering livestock helped the study to assess the consumption of livestock water and compare it to that of general farms which bred some domestic animals as their sidelines. The results of data showed that the daily consumption of water was varied with the difference of districts and seasons in which the investigations were conducted. The results were summarized as follows. 1. The mean consumption of water for home use was varied with the range of 30.2-48.7 lit./day in summer and 22.4-45.2 lit./day per a person, respectively, in the rural districts, which showed that the water consumption in summer was more than in autumn. 2. The mean consumption of livestock water in the general farms approached to about 15.8-37.1 lit./day per cattle, 3.87-16.45 lit./day per a pig, and 0.19-1.03 lit./day per chicken, but it was slightly reduced in autumn; 10.89-37.09 lit./day per cattle, 3.87-12.63 lit./day per a pig, and 0.06-0.94 lit./day per chicken. The ratio of livestock water consumption to home use amounted to the range of 10-25%. 3. The mean consumption of livestock water used at the livestock raisers amounted to 134 lit./day per dairy cow, 67.4 lit./day per cattle, 43.29 lit./day per a horse, 13.24 lit./day per a pig, 0.438 lit./day per a layer, and 0.177 lit./day per a broiler, which showed that the daily water consumption for larger livestock was about two times as much as the farms, but it was approximately of the same for small ones. 4. The factors affecting the amount of water consumption for home use were statistically analyzed to find the kind of water sources and the class of water systems by the factorial arrangement method to the fundamental experimental unit, Suwon area of 100 of families, in which the former was very significant while the latter was significant. However, the standard of living and their interactions were not significant. 5. Almost 83.24% of the sampled farms used some kinds of wells as their water sources, of which 32.06% was of hard water, and of which 11.l% or 2.6% contained much of iron or organice materials, respectively, examining them by a simple technique of sensibility, 6. The resulting chart of the farm water systems was summarized as Fig. IV-6. Observating the safe distance from contamination sources, the ratio of 42.4% of sampled farms whose water sources were wells, confronted highly to the danger of contamination to their water sources. And other dangerous sources of contamination such as toilets, stalls, and compost heaps were situated nearly to the water sources, and most of them were able to make their spoiled water infiltrated into the ground. Thereafter, it was recommended to develop some protecting methods and to install some suitable faculties to clean water.

• Journal of the Korean Institute of Landscape Architecture
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• v.22 no.4
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• pp.75-80
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• 1995

It is important to estimate the possibility of recovery in physiologically damaged woody plant. It is suggested that C.E.R(cambial electrical resistance) might be a useful method to predict the permanent wilting point. D/A and A/D converter can be used to measure the C.E.R and it took only 10-20 msec for a measurement and the values were stable during this study. A computer could be used for the continual measurement of C.E.R. There were very big daily changes of C.E.R. was changed according to the changes of indoor temperature, but the phase was slightly different. It is reasoned that daily changes in C.E.R. is induced by the changes of water potential and cambial thickness. It was difficult to detect the changes of C.E.R. caused by changes in soil moisture under high soil water potential. Under low soil water potential, the changes in soil moisture under high soil water potential. Under low soil water potential, the changes of C.E.R. can be detected. After wilting, C.E.R. is increased very rapidly. When C.E.R. is not decreased by watering, it will be permanent wilting point. But it takes several days to confirm the permanent wilting point. To predict the possibility of recovery from wilting, the values of C.E.R. have no meaning. But the changes of C.E.R. are significant. Therefore we can predict the permant wilting point in woody plant by monitoring the change of C.E.R. by the computer.

• Journal of Bio-Environment Control
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• v.30 no.4
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• pp.367-376
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• 2021

Strawberry cultivation in Korea is grown in greenhouse, but most farms manage their water supply using a timer control method based on the experience of growers. The timer control has problems in that it is difficult to consider the weather condition, the growth stage of crops, and the moisture content of the substrate, so that the crops cannot be managed at an optimal level, and the accuracy of cultivation management are lacking. The watering methods using integrated solar irradiance and substrate moisture contents are control systems that provide eco-friendly and precise water supply considering the growth conditions of crops. The purpose of this study was to compare the combined water supply control with integrated solar irradiance and substrate moisture contents and timer control method in hydroponic cultivation of strawberries using coir, and to set the optimal integrated solar irradiance level for complex water supply control. The irrigation system was automatically watered when it reached 100, 150, 250 J·cm^-2 based on the external solar irradiance, and forced irrigation was performed at a substrate moisture content of less than 60% in all treatments. The amount of irrigation at once was 50 mL. The timer treatment was applied as a control. The smaller the level of integrated radiation to start watering, the greater the daily amount of irrigation. Both the fresh weight and dry weight per plant were higher in the complex irrigation control method than the timer control, and the 100 and 150 J·cm^-2 treatment had the highest fresh weight, and the 100 J·cm^-2 treatment showed a significantly higher dry weight. The yield was also significantly higher in the complex control method than in the timer, and the early yield increased as the level of integrated solar irradiance was smaller. The fresh weight of fruit was the lowest in the timer-controlled irrigation. As a result of this study, the possibility of combined control irrigation method using integrated solar irradiance and substrate moisture content was confirmed for precise water supply management of strawberries in hydroponics.