• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.409-416
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• 2013

Millet and sorghum are major dryland cereal crops, however their growth and productivity is limited by soil water stress with varying intensity. The major objective of this study was to evaluate water stress of millet and sorghum yield under drainage classes of poorly drained soil and to test the effect of the installed pipe drainage in poorly drained paddy soil to minimize crop stress. The research was carried out in poorly drained paddy fields located at alluvial slopping area resulting in non-uniform water content distribution by the inflow of ground water from the upper part of the field. Stress Day Index (SDI) was determined from a stress day factor (SD) and a crop susceptibility factor (CS). SD is a degree of measurement by calculating the daily sum of excess water in the profile above 30cm soil depth ($SEW_{30}$). CS depends on a given excess water on crop stage. The results showed that sum of excess water day ($SWD_{30}$) used to represent the moisture stress index was lower on somewhat poorly drained soil compared with poorly drained soil on 117 days. CS values for sorghum were 57% on $3^{rd}$ leaf stage, 44% on $5^{th}$ leaf stage, 37% on panicle initiation, 23% on boot stage, and 16% on soft dough stage. For proso millet CS values were 84% on $3^{rd}$ leaf stage, 70% on $5^{th}$ leaf Stage, 65% on panicle initiation, 53% on boot stage, and 28% on soft dough stage. And for foxtail millet the values were 73% on $3^{rd}$ leaf stage, 61% on $5^{th}$ leaf stage, 50% on panicle initiation, 29% on boot stage, and 15% on soft dough stage. SDI of sorghum and millet was more susceptible to excess soil water during panicle initation stage more poorly drained soil than somewhat poorly drained soil. Grain yield was reduced especially in proso millet and Foxtail millet compared to Sorghum.

• Journal of Bio-Environment Control
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• v.12 no.2
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• pp.89-94
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• 2003

This study was conducted to identify the effect of recycling method of drained solution on the concentration of drained solution, and growth and yield of tomato in the recycling system. The recycling methods of drained solution were composed of control, MEC (measurement of EC) and ANS (analysis of nutrient solution). The plant height in the early growth stage was not different among the treatments, but plant fresh weight and dry weight were higher in the MEC or the ANS than in the control. The growth including fruit number, fruit weight, and yield of tomato in the ANS as compared with the control was favorable. The EC of drained solution tended to decrease in the early growth stage, but that of drained solution increased in the late growth stage. It was low in the MEC and the ANS as compared with the control. The pH of drained solution was maintained by 6.2 to 6.5 throughout the growth period in the MEC and the ANS, but the pH of the control increased up to 7.2 at the late growth stage. The N and K concentrations of drained solution tended to decrease in the early growth stage, while those of P, Ca and Mg increased. In the late growth stage, concentrations of N, P, Ca and Mg tended to decrease, but that of K in the ANS was very low. Concentrations of N, P, K, Ca and Mg were lower in the MEC and the ANS than in the control.

• Journal of The Korean Society of Grassland and Forage Science
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• v.29 no.4
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• pp.329-336
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• 2009

This experiment was carried out to know adaptability and forage production and quality of corn hybrid for silage at paddy field from 2007 to 2008 at Chungnam province. Growth, forage production and quality of silage corn showed more well drained condition than poorly drained condition at paddy field. Among growth characteristics, 'Kwangpyongok' and 'DK697' hybrids were somewhat strong for waterlogging, then and good at stay green, lodging, disease and insect resistance. Fresh yield of 'DK697' hybrid at poorly drained paddy field was the highest as 32,610 kg per ha among corn hybrids. The dry yield of 'P32P75' hybrid at poorly drained paddy field was the highest as 14,910 kg per ha The result of this study showed that 'P32P75', 'DK697', 'Kangdaok' and 'Kwangpyongok' hybrids had good growth characters and forage productivity at poorly drained paddy field and dry matter yield at poorly drained paddy field was 65.6% level compared with well drained paddy field.

• Applied Biological Chemistry
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• v.28 no.2
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• pp.56-61
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• 1985

The mass balances of calcium salts during the manufacturing processes of Tofu were established by conductometric method and chemical analysis method. During the manufacturing processes of soy milk and Tofu, 66% of solid and 63% of calcium was transfered from soy-bean to the soy milk, and 47.8% of total solid from soybean was transfered to the Tofu, respectively. When the $CaCl_2$ was used as coagulant, calcium contents in Tofu $(Y_{Tofu},\;mg{\cdot}Ca/g{\cdot}Tofu,\;wet\;basis)$ and drained solution $(Y_{drained\;soln},\;mg{\cdot}Ca/ml{\cdot}drained\;soln.)$ were linearly increased with the amounts of $CaCl_2(C,g{\cdot}CaCl_2/ml{\cdot}soy\;milk)$ added in soy milk, and correlative equations between them were obtained as $Y_{Tofu}=0.3369\;C+1.2689$ for Tofu$(moisture\;content:\;81.5{\pm}0.5%)$ with r=0.9898, and $Y_{drained\;soln}= 0.2899C+0.0399$ for drained solution with r= 0.9991. It was proved that conductometric method was reasonably applicable to the measurement of calcium contents of the products from every processes of Tofu manufacture except soy-bean. However the conductometric method was not recomendable in the case of $CaSO_4$ as coagulant due to its low solubility ana uneven distribution in soy milk and Tofu tissue.

• Journal of the Korean Geotechnical Society
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• v.31 no.6
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• pp.71-82
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• 2015

Recently, due to the expansion of urban infrastructure for the citizen convenience, the shield tunnel construction has increased considering the civil complaints minimization and construction stability. Most shield tunnels are designed based on the assumption of the undrained condition that underground water does not inflow, but they are operated in the field as drained tunnels with drainage facility to drain underground water. Therefore, the drained condition needs to be considered in the shield tunnel design. It is also necessary to consider the weathered granite soil that is widely distributed throughout the country and consequently is encountered in most of construction sites. In this paper, the model test which can control total stress and pore water pressure and simulate the underground tunnel located in the weathered granite soil below ground water level is conducted. Total stress, pore water pressure and an inflow water into an inner pipe were measured using the testing device. Test results showed that the total stress in a drained condition was lower than in an undrained condition because pore water pressure decreased in a drained condition and an inflow water into an inner pipe was proportional to the loading stress in a drained condition. As a result, if a drained condition is considered in the shield tunnel design, the more economical design can be expected because of the stress reduction of the lining.

• Journal of the Korean Society for Marine Environment & Energy
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• v.5 no.3
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• pp.3-9
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• 2002

When a flooding a lot of debris are drained from rivet. Drained debris separated lodgement debris and floating debris, and floating debris moving other region by wind and ocean current. This experimentation throw three buoys which installed with DGPS and other devices in nak-dong river, and check there location every minute. In consequence of this experimentation, floating debris drained nak-dong river are gathered near Dadaepo seaside or drifted Dong hae. Ocean current and wind driven current are largely influenced then tide. Numerical analysis calculated by MAPCNTR(develop by KRISO) is similar to the result of this experimentation.

• Geomechanics and Engineering
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• v.30 no.3
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• pp.219-231
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• 2022

Geotechnical materials such as silt, fine sand, or coarse granular soils may be unstable under undrained shearing or during rainfall infiltration starting an unsaturated state. Some researches are available describing the instability of coarse granular soils in drained or undrained conditions. However, there is a need to investigate the instability mechanism of unsaturated silty soil considering the effect of degree of compaction and net confining stress under partially and fully drained conditions. The specimens in the current study are compacted at 65%, 75%, & 85% degree of compaction, confined at pressures of 60, 80 & 120 kPa, and tested in partially and fully drained conditions. The tests have been performed in two steps. In Step-I, the specimens were sheared in constant water content conditions (a type of partially drained test) to the maximum shear stress. In Step-II, shearing was carried in constant suction conditions (a type of fully undrained test) by keeping shear stress constant. At the start of Step-II, PWP was increased in steps to decrease matric suction (which was then kept constant) and start water infiltration. The test results showed that soil instability is affected much by variation in the degree of compaction and confining stresses. It is also observed that loose and medium dense soils are vulnerable to pre-failure instability i.e., instability occurs before reaching the failure state, whereas, instability in dense soils instigates together with the failure i.e., failure line (FL) and instability line (IL) are found to be unique.

• Korean Journal of Agricultural Science
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• v.49 no.3
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• pp.629-641
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• 2022

This research was conducted to secure fundamental data for development of a recirculating hydroponic system. To achieve this, Lycopersicum esculentum var. 'Dafnis' and 'TY Tiny' were grown with Yamazaki hydroponic solution and the inorganic element concentrations of plant leaves and nutrient solution of supplied and drained were analyzed periodically. The T-N and P contents in both varieties of tomato leaves showed gradual decreasing tendencies with the passage of time. The 'TY Tiny' tomato had higher contents of those two nutrients than 'Dafnis' tomato in the late stage. The K content of 'Dafnis' tomato was high in the early growth stage, but low in the late stage. However, that of 'TY Tiny' tomatoes rose in the late stage. The Ca content gradually increased in both varieties of tomato in the latter stages. The EC of the drained nutrient solution in both varieties of tomato showed increasing tendencies as time had passed, but the pH was get lowered in the drained solution. The concentrations of NO₃-N, K, Ca, Mg, Na, Fe, and B, except PO₄-P in the drained nutrient solution were generally higher than those in the supplied solution, especially in the period of October through December. The above results can be used for controlling of nutrient concentrations in the recirculated hydroponic cultivation of tomato.

• Journal of the Korean Geotechnical Society
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• v.22 no.6
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• pp.5-13
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• 2006

Effective stresses may decrease due to generation of excessive pore pressure at the interface between soil and reinforcement in undrained condition such as rapid drawdownof groundwater level, resulting in the decrease in pullout capacity of the reinforcement. In this research, a series of laboratory pullout tests have been performed on different materials (clean sand, 5, 10, 15 and 35% silty sand), different overburden pressures (30, 100 and 200 kPa), and different drainage conditions (drained and undrained) in order to compare drained pullout capacity with undrained pullout capacity. The test results show that both drained and undrained pullout capacity are influenced by silt contents and increase with the increase of friction angle of the soil. The pullout capacity and the pullout displacement required to reach the peak value also increase as the overburden pressure increases. In undrained condition, the effective stresses acting on the reinforcement decrease as excessive pore pressures are generated, resulting in the decrease in pullout capacity and pullout displacement.

• Journal of Biosystems Engineering
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• v.24 no.4
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• pp.293-300
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• 1999

The objectives of this study were to analyze the load acting on the transmission when tractor performed rotary operations in the poorly drained paddy fields and to compare its severeness with those obtained under different operational conditions. The loads were measured at the input shaft of the transmission and the load spectrum was constructed using the rain-flow cycle counting method. The severeness of the loads was represented by the partial damage sum which was determined by suing the modified Miner's rule. In the field with a shallow hardpan PTO speed affected severeness of the rotary operations greater than the forward speed did. In the field with deep hardpan, on the other hand, the effect of the forward speed was greater. the severeness in the well drained fields did not differ significantly from that in the field with a shallow hardpan. The severest load was recorded in the field with a deep hardpan.