• Journal of Practical Agriculture & Fisheries Research
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• v.17 no.1
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• pp.57-71
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• 2015

This study was conducted to develop the fertigation system with a peristaltic hose pump and brushless DC motor. The fertigation system was consisted of sensor, main controller, motor control unit, peristaltic pump, water supply pump, control panel, and filter. The peristaltic pump discharges liquid by squeezing the tube with rollers. Rollers attached to the external circumference of the rotor compresses the flexible tube. The fluid is contained within a flexible tube fitted inside a circular pump casing. The developed fertigation system has no mixing tank but instead injects directly a concentrated nutrient solution into a water supply pipe. The revolution speed of the peristaltic pump is controlled by PWM (Pulse width modulation) method. When the revolution speed of the peristaltic pump was 300rpm, the flow rate of the 3.2, 4.8, 6.3mm diameter tube was 202, 530, 857mL/min, respectively. As increasing revolution speed, the flow rate of the peristaltic pump linearly increased. As the inner diameter of a tube larger, a slope of graph is more steep. Flow rate of three roller was more than that of four roller. Flow rate of a norprene tube with good restoring force was more than that of a pharmed tube. As EC sensor probe was installed in direct piping in comparison with bypass piping showed good performance. After starting the system, it took 16~17 seconds to stabilize EC. The maximum value of EC was 1.44~1.7dS/m at a setting value of 1.4dS/m. The developed fertigation system showed ±0.06dS/m deviation from the setting value of EC. In field test, Cucumber plants generally showed good growth. From these findings, this fertigation system can be appropriately suitable for fertigation culture for crops.

• Korean Journal of Soil Science and Fertilizer
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• v.42 no.6
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• pp.492-499
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• 2009

Effect of drip irrigation on soil salinity control and growth of vegetable crops was studied in the three reclaimed lands of Korea in 2007. Drip irrigation was done one or two times per month for reduction of salt stress by using vinyl hose with tiny holes laid on ridge surface under black plastic film mulch during growing season of cabbage and chinese cabbage. It was observed that drip irrigation was generally effective to soil salinity control, but soil salinity variation of some place was not fully solved to lower down under level of free salt stress. It is also considered that high salinity of runoff water spilled out from cultivation ridge plays another key role for soil salinity management. Consequentially, this soil salinity variation might be one of factors brought low average yield and low commercial ratio of agricultural products. Relation between soil salinity and head growth of cabbage and chinese cabbage was well expressed as logarithmic function. Surface soil EC to reach at 50% of growth reduction to the heaviest head can be estimated was $6.1dS^{\circ}{\S}m^{-1}$ for cabbage and $5.7dS\;m^{-1}$ for chinese cabbage transplanted at optimum season.

• Journal of the Korean GEO-environmental Society
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• v.11 no.9
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• pp.55-60
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• 2010

This study are carried out to an lab model tests to develop a construction method that solidifies high-water content cohesive soil by using filter type drain and vacuum pressure, and that stabilizes the ground by accelerating horizontal drain at incline or in tunnel. The calibration chamber was designed within length of 1.5m and height of 50cm, and a drainage hole for preconsolidation, a switchgear and a piezometer were installed at the bottom part of the chamber. Also, a settlement gage was installed at the top part so that it can measure the settlement by time. The calibration ground basis was made in a form of thin layer from kaolinite and bentonite in 9:1 ratio stirred at 130% water content condition. A filter type drain was installed at chamber center and a vacuum pressure of 0.8MPa was applied through a hose linked to the cap at the top part, then, the settlement was measured in every 1 hour interval. After experiment, the moisture contents were measured by position, then, verified the increase of solidity of the ground through a triaxial compression test on undisturbed profile. After 11 days from the effective date, it was observed that the settlement decreased by maximum 35mm and the water content ratio was reduced by 38% at most while the solidity of the ground increased by 5~8 times greater than before preconsolidation.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.58-58
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• 2017

점적 호스의 원통형 미로 구조물내의 유동특성을 분석하기 위해 금속판에 동일한 구조의 미로가 가공된 시험부를 활용하여 압력과 유량의 변화에 대한 실험을 CFD 해석하였다. 해석은 미로의 길이에 따른 유량 특성을 정밀하게 분석하기 위해 전체 미로에 구간별 총 8개의 배출구를 배치하고 밸브 조절을 통해 구간별 압력에 따른 유량을 측정함으로서 실험에 의한 압력과 유량의 관계를 검증하고 새로운 경질 미로를 설계하는데 응용하고자 한다. 경질 미로의 이론적인 해석에서 정밀도가 실험을 대신할 가능성이 있는지에 관심을 두었다. 점적관수의 경질 미로는 디자인을 달리함으로써 성능이 높고 미세한 스케일이 침착되지 않는 고성능의 점적관수 장치의 개발이 가능할 것으로 판단하였다. 미로 입구의 공급 유체 압력(Gauge pressure)을 0.5, 1.5, 2.5, 3.0 bar로 나누어 공급하였으며, 8개의 구간별 유출되는 유량은 전자저울에서 측정하였다. 향후 최적 미로의 새로운 설계를 위해 미로구조 전체를 CFD 해석하였고 그 결과를 실험치와 비교 분석하였다. 또한 경질 미로내 각 구간별 세부적인 유동구조를 분석하였고 해석결과와 실험결과를 통해 향후 새로운 경질 구조의 개발이 가능 할 것으로 판단되었다. 경질 미로의 입구압력에 따른 미로의 길이 #1과 #2에 대한 CFD 분석에서는 전체적으로 경질 미로에 압력이 증가할수록 미로의 유체 속도가 증가됨을 알 수 있었으며 이것은 #2에서도 거의 같은 양상을 나타내었다. 미로 통로에서는 와류로 인한 이물질의 멈춤 현상이 발생하지 않을 만큼 흐름이 원활함을 알 수 있었다. 미로의 길이 #3과 #4에 대한 CFD 분석과 미로의 길이 #5와 #6에 대한 CFD 분석에서는 압력이 증가하고 미로의 길이가 길어질수록 속도에도 영향을 미치고 있는 것으로 나타났으며 미로와 미로 사이의 넒은 통로에서는 유속이 크게 떨어지고 있음을 알 수 있었다. 따라서 이 부분에는 유체속의 이물질이 침착할 수 있는 가능성이 있으며 통로가 좁은 곳에서는 유속이 증가되는 것으로 나타났다. #7과 #8은 미로의 상하단으로 유출되는 부분의 차이이므로 실질적으로 해석의 결과는 차이가 없었다. 경질 미로에 대한 압력에 따른 미로의 길이별 유출량은 지수적인 반비례 현상을 나타내어 앞서 실험한 연구의 결과와 1~2% 오차 범위에서 잘 일치하였다. 따라서 점적 호스의 경질 미로에 대한 설계는 이론적인 해석을 통하여 새로운 디자인이 가능할 것으로 판단되었다. 경질 미로의 미로의 길이에 따른 CFD 분석의 결과는 실험적인 유출량의 값과 거의 일치하였다. 미로와 미로 사이의 넒은 통로에서는 유속이 크게 떨어져 이물질들이 침착될 가능성이 있었으며 실질적으로 넓게 설계하는 것이 유리하지 않을 것으로 판단되었다. 경질 미로에 대한 압력에 따른 미로의 길이별 유출량은 지수적으로 반비례 하였으며 점적 호스의 경질 미로에 대한 새로운 설계는 이론적인 해석을 통하여 가능할 것으로 판단되었다.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.57-57
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• 2017

Water line은 UV 처리된 호스의 내부에 압력보상 기능이 첨부된 경질의 미로 튜브를 끼워 사용하도록 제작되어 있다. 점적 호스의 외경은 15.8mm이며 대부분 0.5~2.5bar 사이의 압력에 1.5~3.0 L/hr의 유량을 공급한다. 따라서 전적 호스의 내부에 위치한 경질 미로 튜브의 설계는 유량의 압력보상에 밀접한 관계가 있다. 본 연구에서는 경질 미로 튜브를 통과하는 작은 돌기의 수가 압력과 유량에 어떤 영향을 미치는지에 대한 기초적인 실험을 수행하였으며 경질 미로의 압력과 유량 특성에 따른 이론적 해석과의 비교분석을 통하여 새로운 미로의 형상 설계에 활용할 기초적 연구를 수행하고자 하였다. 점적 호스의 성능은 길이(보통 300~400m)에 대한 유량의 균등성을 유지하는 것이며 균등성은 압력보상에 의해 이루어진다. 원통형 미로는 점적 호스의 내부에 삽입되어 원통 부분에 형성된 미로의 길이에 따른 유량의 균등성을 유지하도록 설계되어 있다. 점적 호스의 원통 주변에는 8개의 미로로 구성되어 있으며 미로의 길이를 금속 평면으로 금형 제작하여 투명판에서 미로의 형상을 보이게 하였다. 또한 입구부분에 물을 공급하고 미로의 각 위치별 배출구를 설치하여 압력에 따른 유출량을 전자저울에 측정하여 압력별 유량의 균등성에 대한 데이터를 측정하였다. 유입구의 압력을 0.5, 1.5, 2.5, 3.0bar로 각각 공급하였으며 유출량은 미로의 8개 구간에 따라 측정하였다. 경질 미로의 유출량은 미로의 길이가 짧을수록, 압력이 커질수록 유출량이 높게 나타났다. 또한 미로의 길이가 짧을 경우에는 유출량의 차이가 비교적 크게 나타났으나 미로의 길이가 길수록 압력에 대한 유출량에 대한 차이가 크지 않음을 알 수 있었다. 따라서 경질 미로에서 미로의 길이를 길게 할 경우에는 유출량을 비교적 균일하게 할 수 있음을 보여주고 있다. 반면에 미로의 길이가 길어질수록 압력변화에 따른 유출량이 지수적으로 감소함을 나타내고 있다. 미로의 길이가 7번과 8번에서는 상당히 균일한 성능을 보여주므로 경질 미로의 배출구를 전체적으로 모두 활용함으로써 압력보상을 비교적 균일하게 할 수 있음을 보여주고 있다. 압력보상은 탄성을 가진 실리콘과 미로로 구성될 경우에 가장 큰 효과를 나타내지만 점적 호스와 같이 경질 미로만으로 압력보상을 해야 할 경우에는 경질 미로의 길이가 매우 중요하다.

• The Research Journal of the Costume Culture
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• v.4 no.3
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• pp.305-323
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• 1996

The purpose of this sty is to forecast the tendency of clothing colors, to provide materials useful for making the color plan for a better costume, and suggest new information in the apparel industry. To achieve these purposes, this study was carried out by suggesting vogue colors of recent apparel, along with the 20 standard colors of Muncell to 350 men and women in their 20s residing in Taegu.. We analysed and compared their preferred colors in suits vidual factor ;age, sex, education ,skin color, and body shape, and additionally classifying their interest in clothing colors, cause for color selection , degree of interest in color of clothes, color satisfaction of apparel market, and color combination of clothing, color satisfaction of apparel market, and color combination of clothing. We compared these elements according to their age, sex, and education. The results of this study is summarized as follows; 1. It was shown that both men and women in their 20s preferred warm colors the first colors mentioned being the most popular ; Pastels, Red, Blue and Black. They disliked dark and sordid colros in the order of Mauve, Khaki and Red. They preferred wearing Pastels and Yellow in the Spring, White, Blue, and Pastels were the favorites for summer, Beige in autumn, and black, Gray, and Beige in winter. The repugnated colors they chose two wear were Black, Red, Mauve, Khaki in spring and summer. Mauve, Red, Yellow were favorites for autumn, and Blue·White, Yellow·Green, and Pastels in winter. 2. The preferred colors for T-shirts were Yellow, Pastels, White in spring. White and Pastels were summer favorites, Beige an Red for autumn, and Black, Red, Beige in Winter. As for suits, the preferred colors in spring were in the order of Pastels, Beige and Yellow. The preferred colors of upper garments in summer were in the order of White and pastels. for lower summer garments Pastels, White and Blue were favorites. In autumn, Beige was shown to be highly preferred, and in winter, the order of preferred colors was Black, Gray and Beige. 3. On of those individual factors showing the greatest difference was sex. 4. Those factors having the greatest impact on the selection of clothing color were the season and their preference color. 5. The in vogue color of men in their 20s was at a higher level than hat of women. The groups that had an upper college level education showed a significant difference in their choices thant hose who were highschool graduates and technical college student and graduates. The consideration of inteterest in color of clothes, holding clothes during new purchasing, body shape and skin color was higher for women than men. In buying and wearing accessaries, women tend to take into consideration the harmony with the garment, and there was shown a significant difference between highschool graduates and the groups above the level of college education.

• Journal of Bio-Environment Control
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• v.7 no.2
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• pp.151-158
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• 1998

This study was carried out to evaluate the effect of substrates and nutrient solution supplying methods in the media culture using perlite and its mixtures with rice hull, carbonized rice hull. cocopeat on the growth and fruit qualify of hydroponically grown cucumber. Three substrates. Perlite(70%) +rice hull(30%) perlite(70%) +carbonized rice hull(30%) and perlite(70%)＋cocopeat(30%) were compared with perlite medium. Supplying methods of nutrient solution were composed of drip irrigation, modified drip irrigation(covered with cheesecloth between drip hose and substrate) and mist system Leaf area of cucumber Plants was lowest in perlite medium while it was highest in mixture of perlite and cocopeat. NAR was higher in the plot of mixture with cocopeat. and same trend was observed in LAI and CGR. T/R ratio was higher in Perlite and perlite mixture with rice hull. Fruit Yields increased in the plot of modified drip irrigation system. When perlite mixture with rice hull used as a substrate. mist system was recommended. Perlite mixture with carbonized rice hull was observed favored in conventional drip irrigation system. Marketable yield and the number of fruit per plant increased and the malformed fruit decreased in the plot of modified drip irrigation system with the mixtures of Perlite and cocopeat.

• Journal of Bio-Environment Control
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• v.20 no.3
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• pp.197-203
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• 2011

This experiment was carried out to investigate the growth characteristics of virus-free sweetpotato in hydroponic bag culture. The rooted one-node and upper-shoot cuttings of 'Yeonhwangmi' and 'Mannamiwere' transplanted into the plastic bag (0.5 mm of thickness, $W300{\times}L1,200{\times}H120mm$) culture system filled with commercial horticultural media (TKS-2, Flora Gard Co.) and cocopeat + perlite (3 : 7, 5 : 5, 7 : 3, (v/v). Nutrient solution of National Horticultural Research Station in Japan was separately irrigated $3times{\times}30minutes$ per day (10:00, 14:00 and 20:00 with timer control) by the drip irrigation. The growth of two varieties was not significantly different among four substrates in 15 days, but it was excellent in commercial horticultural media (TKS-2) and cocopeat 3 : perlite 7 (v/v) in 20 days. The growth in 'Yeonhwangmiwas' promoted than that in 'Mannami', and the upper-shoot cuttings of 'Yeonhwangmi' and 'Mannami' showed a significant vine elongation (over 10 and 2 cm, respectively) compared to the one-node cuttings. Fresh weight and dry weight in cocopeat 3 : perlite 7 (v/v) were significant increased than that in cocopeat 7 : perlite 3 (v/v). Therefore, the bag culture system filed with cocopeat 3 : perlite 7 (v/v) was successfully applied on propagation of virus-free sweetpotato seedling, and the result expected that the bag culture system could be commercialized without high financial costs for farmers.

• Journal of the Korean Institute of Gas
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• v.10 no.3 s.32
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• pp.54-59
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• 2006

A safety device with shut-off function was developed for preventing intentional accidents that might happen by separating of cutting hoses connected to pressure regulators used in residential LP gas facility. For the verification of function and field adaptability, the safety device with shut-off function was tested in the state of joining the device to the regulator and a field test was carried out at home. This study shows that, at the inlet pressure of 0.07-1.56 MPa, the device shuts off the gas within the 5m length of hose regardless of the installation condition of the regulator. The shut-off flow rate increases in the order of perpendicular upward, horizontal and perpendicular downward. From the results of the field tests carried out at home for 5 months, there appears no problem using a gas range or a boiler. If the developed shut-off device is commercialized and distributed in the market the intentional accidents occurred by cutting or separating hoses can be prevented remarkably.

• Journal of Nutrition and Health
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• v.34 no.8
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• pp.872-880
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• 2001

The purpose of this study was to investigate the effects of glucuronic acid on antioxidative defense system and recovery of muscle fatigue in rat artier aerobic exercise. Sprague-Dawley male rats weighing 150 $\pm$ 10g were randomly assigned to one normal(N) group and three exercise training groups. Exercise training groups were classified into glucuronic acid free intubation group(T group), 250mg glucuronic acid/kg bw intubation group(TU group), and 500 mg glucuronic acid/kg bw intubation group(2TU group) according to glucuronic acid supplementation level. The glucuronic acids were administered to rats by oral intubation before exercise training. The experimental rats in exercise training groups(T, TU and 2TU) were exercised on glucuronic acid supplementation or rats in normal group were confined in cage for 4 weeks. And rats were sacrificed with an overdose of pentobarbital injection just after running. Liver xanthine oxidase(XOD) activities were not significantly different among four groups. The activity of superoxide dismutase(SOD) in T group was no significant difference from N group, but those of TU and 2TU groups were increased by 9% and 18%, respectively, compared with that of T group. Liver glutathione peroxidase(GSHpx) activites of T and TU groups showed a similar tendency to that of normal group, but increase 17% in 2TU group compared with normal group. The ratio of GSH/GSSG in liver of T group was lower than that of normal group, but those of TU and 2TU groups were a similar tendency to that of normal group. Contents of thiobarbituric acid reactive substance(TBARS) in T group was increased by 47%, compared with that of normal group but those of TU group and 2TU group were lower 27% and 35%, respectively, compared with that of T group. The contents of glycogen in soleus muscle significantly lower in all three trained exercise groups than that of normal group, but there were no significant differences among the trained exercise groups. Contents of hepatic glycogen in T group were decreased 27% compared with those of normal group while those of TU and 2TU groups were the same as normal group levels. The contents of serum lactic acid in T group were increased 240% of normal group, but hose of TU and 2TU groups were decreased 38%, 39%, respectively, by glucuronic acid supplementations, compared with that of T group. In conclusion, the effects of glucuronic acids in exercise training rats would appear to reduce peroxidation of tissue as an antioxidative defense mechanism and promote recovery of muscle fatigue.