• Ocean Systems Engineering
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• v.4 no.4
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• pp.263-278
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• 2014

The spudcan requires the suitable design considering the soil, platform, and environmental conditions. Its shape needs to be designed to secure sufficient reaction of soil so that it can prevent overturning accidents. Its shape also has to minimize the installation and extraction time. Even in the same soil condition, the reaction of soil may be different depending on the shape of spud can, mainly the slope of top and bottom plates. Therefore, in this study, the relation between the slope of plates and the reaction of soil with and without water jetting is analyzed to better understand their interactions and correlations. For the investigation, a wind turbine installation jack-up rig (WTIJ) is selected as the target platform and the Gulf of Mexico is considered as the target site. A multi layered (sand overlying two clays) soil profile is applied as the assumed soil condition and the soil-structure interaction (SSI) analysis is performed by using ANSYS to analyze the effect of the slope change of the bottom plate and water jetting on the reaction of soil. This kind of investigation and simulation is needed to develop optimal and smart spudcan with water-jetting control in the future.

• Journal of Environmental Science International
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• v.19 no.9
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• pp.1137-1142
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• 2010

This study proposes a guideline of a green roof system suitable for the local environment by verifying the growth of Zoysia japonica in a shallow, extensive, green roof system under rainfed condition. The experimental soil substrates into which excellent drought tolerance and creeping Z. japonica was planted were made with different soil thicknesses(15cm, 25cm) and soil mixing ratios(SL, $P_7P_1L_2$, $P_6P_2L_2$, $P_5P_3L_2$, $P_4P_4L_2$). The plant height, green coverage ratio, fresh weight, dry weight and chlorophyll contents of Z. japonica were investigated. For the soil thickness of 15cm, the plant height of Z. japonica was significantly as affected by the soil mixing ratio and it was shown in the order SL= $P_4P_4L_2$ < $P_7P_1L_2$ = $P_5P_3L_2$ < $P_6P_2L_2$. For the soil thickness of 25cm, the plant height was increased in order to SL < $P_7P_1L_2$, $P_6P_2L_2$, $P_5P_3L_2$ < $P_4P_4L_2$. The green coverage ratio was not observed by soil the mixing ratio or soil thickness. However, the green coverage ratio was 86~90% with a good coverage rate overall. The chlorophyll contents of Z. japonica were not significantly affected by the soil mixing ratio in the soil thickness of 15cm, but were higher in the natural soil than in the artificial soil at 25cm soil thickness. The fresh weight and dry weight of Zoysia japonica were heavier in the 25cm thickness than in the 15cm thickness and in the artificial soil mixture than in the natural soil. The result indicated that the growth of Zoysia japonica was more effective in the 25cm soil thickness with artificial soil than in the 15cm soil thickness with natural soil in the green roof system under rainfed condition.

• Journal of the Korean GEO-environmental Society
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• v.18 no.11
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• pp.13-18
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• 2017

In a banking process for construction of a complex, non-compaction construction has been applied in most sites, which is a method that soils are compacted by the equipment load without being compacted separately. However, there are no specific descriptions in the construction manual or specifications, so it is unclear to evaluate the excavation volume. Hence, this study is a basic study to compare the soil conversion factor at a design stage and the actual soil conversion factor of a banking ground under a non-compaction condition in order to examine the feasibility in constructing the ground for construction of the complex and to examine appropriateness of the earth work in the site by conducting an indoor, field, and load-settlement test and proposing a reasonable soil conversion factor. Under the non-compaction condition, the soil conversion factor C is set to be 1.0 at the design stage, but the result of the field test was 0.86 which is smaller than the value at the design stage. It was expected that this result would increase the banking volume, and the construction result actually showed a difference in the banking volume. Therefore, for the baking ground under the non-compaction condition, it is necessary to apply the value C suitable for the site condition after performing test by considering the site's condition and the banking height.

• Asian Journal of Turfgrass Science
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• v.23 no.2
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• pp.229-240
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• 2009

The high temperature and water content in soil profile probably affect the physiological disorder especially on cool-season turfgrasses in warm and humid weather of Korean summer. The purpose of this research was to analyze the effect of soil temperature and water content on the growth and stress response of creeping bentgrass(Agrostis palustris Huds.) under a humid and warm temperature. USGA(United State of Golf Association) green profile in laboratory test, Daily temperature changes were tested under a dried sand, 70% water content of field capacity, and saturated condition at $34^{\circ}C$ of the USGA green in lab. In this test, the dried sand reached to $80^{\circ}C$, however, the surface temperature decrease of $10^{\circ}C$ on the saturated condition. In the thermal properties test in field, thermal conductivity, thermal diffusivity, and soil temperature were increased followed by irrigation practise. In the water-deficient condition, the highest soil temperature was reached temporally right after irrigation, however, the excessive soil water content higher than field water holding capacity showed the highest soil temperature after a while. This result indicated that a heat damage to root system was caused from the thermal conductivity of a high surface soil temperature. The excessive irrigation when a high turf surface temperature should occur a negative result on tufgrass growth, moreover, it would be fatal to root growth of creeping bentgrass, especially when associated with a poor draining system on USGA sand green. Overall, this study shows that high soil temperature with water-excessive condition negatively affects on cool-season grass during the summer season, suggesting that excessive irrigation, over 70% field capacity of soil condition, does not help to reduce soil temperature for summer season in Korea. In the study that cool-season grass were treated with different water content of soil, The soil had higher temperature and more water holding capacity when treatment rate of soil conditioner was increased. The best growth at the normal water condition and the worst state of growth at thee water-excessive condition were observed.

• Korean Journal of Soil Science and Fertilizer
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• v.27 no.4
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• pp.263-268
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• 1994

Field microplot(D 20cm, L 85cm) experiment filled with Bonryang sandy loam soil(Typic Udifluvents) was conducted to obtain quantitative information on the change of soil pH under different soil moisture regime and ladino clover cultivation, and the movement of applied nutrient under the rainfed bare soil condition. Slaked lime increased soil pH of the applied layer. $NH_4-N$ evolved from urea hydrolysis was more effective in raising the subsoil pH rather than the exchangeable Mg and Ca. Under the different soil miosture condition downward movement of Cl and $NO_3-N$ lowered subsoil pH during the middle of ladino clover growth. Leaching of CI and $NO_3-N$ down to the out of the soil microplot and increasing movement of Ca and Mg into the subsoil produced. a slight increase of subsoil pH during the late crop growth. The mean downward movement of applied nutrient 5.5 months after field installation of microplot in the bare soil under rainfed condition(1207mm) was in the order : Cl= more than 80.0>Inorganic nitrogen= 75.8>K= 67.3>Mg=62.7>Ca=18.1>P=2.3cm respectively.

• Korean Journal of Soil Science and Fertilizer
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• v.20 no.3
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• pp.261-268
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• 1987

A green house experiment was conducted to find out the differences in the amount of biologically fixed nitrogen and kjeldahl nitrogen on the different soil texture, kinds and amounts of fertilizer nitrogen under light (photosynthetic $N_2$-fixation) and dark (heterotrophic $N_2$-fixation) condition in submerged paddy soil. The reults obtained were summarized as follows; 1. The amount of biologically fixed nitrogen per mg carbon from different organic matter was obtained as 0.13 mg in glucose, 0.09 mg in rice straw, and 0.07 mg in refused mushroom compost and barley straw under 60 days of incubation. 2. Nitrogen fixing activities were decreased with increase of fertilizer nitrogen and those tendency was pronounced more in sandy soil with application of urea than that of ammonium sulfate. 3. The application of ammonium sulfate in sandy soil under light condition was increased the photosynthetic $N_2$-fixation and the applied urea was remarkably reduced the heterotrophic $N_2$-fixation in sandy soil. The proportion of biologically fixed total nitrogen after experiment in sandy soil was obtained as 25% for dark(heterotrophic $N_2$-fixation) and 75% for light (photosynthetic $N_2$-fixation) condition. On the other hand, very similar biological $N_2$-fixing tendency was obtained between kinds of nitrogen fertilizer and two light condition in clayey soil. 4. The kjeldahl nitrogen was remarkably decreased after experiment under dark condition with application of urea than that of light condition with ammonium sulfate, and no remarkable decreasing tendency was obtained in clayey soil between two kinds of fertilizer nitrogen. 5. The high significant positive correlationship was obtained between calculated biological nitrogen fixation by acetylene reducing activity and kjeldahl nitrogen after experiment under light (y=0.8488X-5.9632, $r=0.9928^{**}$, n=21) and dark (y=0.8795X-7.1056, $r=0.9782^{**}$, n=21) condition. In this experiment condition, conversion factors of 6:1 was obtained from biological nitrogen fixation to soil nitrogen.

• International Journal of Internet, Broadcasting and Communication
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• v.12 no.1
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• pp.130-136
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• 2020

There are many problems that occur currently in agriculture industries. The problems such as unexpected of changing weather condition, lack of labor, dry soil were some of the reasons that may cause the growth of the plants. Condition of the weather in local area is inconsistent due to the global warming effect thus affecting the production of the crops. Furthermore, the loss of farm labor to urban manufacturing jobs is also the problem in this industry. Besides, the condition for the plant like air humidity, air temperature, air quality index, and soil moisture are not being recorded automatically which is more reason for the need of implementation system to monitor the data for future research and development of agriculture industry. As of this, we aim to provide a solution by developing IoT-based platform along with the irrigation for increasing crop quality and productivity in agriculture field. We aim to develop a smart garden system environment which the system is able to auto-monitoring the humidity and temperature of surroundings, air quality and soil moisture. The system also has the capability of automating the irrigation process by analyzing the moisture of soil and the climate condition (like raining). Besides, we aim to develop user-friendly system interface to monitor the data collected from the respective sensor. We adopt an open source hardware to implementation and evaluate this research.

• Korean Journal of Environmental Agriculture
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• v.27 no.4
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• pp.456-459
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• 2008

Quality of rice grain changes during dry storage with internal physiological changes and external injury by organism. Storage rice changes by condition with respiration via variable temperature, hydrolysis enzyme reaction, lipid peroxidation occurs with change of palatability. During dry storage, physiological change with protein variation pattern was examined by image analysis on proteomic technology. Analysis revealed that protein activity had no change store at room temperature and store at $40^{\circ}C$, but decreased store at $60^{\circ}C$. Analysis of variable hydrophobic protein pattern revealed that protein activity of beta-tubulin, protein disulfide isomerase, vacuolar ATPase b subunit, globulin was not significantly decreased all dry and store condition. However, heat shock protein 70, and glutathione transferase was significantly decreased when rice dried at $60^{\circ}C$ compared with room temperature and $40^{\circ}C$ dry condition.

• Korean Journal of Environmental Agriculture
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• v.34 no.1
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• pp.1-5
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• 2015

BACKGROUND: The stabilities of the two alkaloidal insecticides of S. flavescens including matrine and oxymatrine are important factor to establish expiry date and usage manual for crop protection. However, the environmental stability of the compounds had not been studied with the extract and its commercial biopesticide. METHODS AND RESULTS: The environmental stabilities of the two alkaloids were performed with extract of S. flavescens, and its two commercial biopesticides both in controlled aquatic and soil conditions. The half-lives of the total matrines for the extract and its two commercial biopesticides were estimated over 200 days both under aerobic and anaerobic water condition. Under dry soil condition, the initial decay rates of the matrines were calculated 0.0804-0.1275 ($t_{1/2}$ 5.4-8.6 days), and the half-lives under wet soil condition were calculated 33.0-231 days. Total soil bacteria on the wet soil ranged 6.0-8.0 log CFU/g-soil during the experiments period. CONCLUSION: The aquatic mixture of the extract showed excellent stability both with the extract and its biopesticides, however, the stability of soil mixture were shorter than the aquatic mixture, suggesting that soil metal consider as a catalyst for the degradation of the two alkaloids.

• Journal of the Korean Geotechnical Society
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• v.15 no.6
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• pp.273-283
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• 1999

When microorganism is injected into porous medium such as soils, biomass is retained in the pore. Soil pore size and shape are varied from the initial condition as a result of biofilm formation which makes hydraulic conductivity reduced and friction rate between soil aggregates increased. In this research, hydraulic conductivity reduction was measured after microorganism are inoculated and cultured with synthetic substrate and nutrient. In addition, this research evaluated the applicability of biomass-soil mixture to the field condition as an alternative cover material in landfill by measuring hydraulic conductivity change after repetitive freeze-thaw cycles. Hydraulic conductivity of silty soil decreased by approximately 1/50 after biomass inoculation and cultivation. Biofilm attached on soil aggregates is resistant to acidic or basic condition. After repetitive freeze-thaw cycles, however, hydraulic conductivity increase implies that biomass clogging can be impaired.