• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.7 no.4
• /
• pp.91-102
• /
• 1987

In this study, the finite element method using 8-node isoparametric element is developed theoretically and simulated to see the deformation of soil and plate, when the circular plate resting on Boussinesq's soil type is loaded axisymmetrically. The results of numerical analysis using the Mohr-Coulomb yield criterion, and experimental analysis are approximative, assuming that soil is elasto-plastic medium. The paper shows that the plastic zone of soil medium is displayed at the near the edge of plate at the first place; when the plastic zone of soil medium is linked around central axis, the external load is termed by critical load, and then the contact pressure changes abruptly, in this case it is approved to be the risk of shear failure.

• Journal of Applied Biological Chemistry
• /
• v.42 no.3
• /
• pp.140-145
• /
• 1999

Livestock manure is generally beneficial to soil and crop production when appropriate amount is applied, but excessive application may be detrimental to soil and water environments. A proper protocol of livestock waste treatment is required to manage the quality of soil and water. A trickling filter system using rice straw media was employed to treat piggery wastewater from small-scaled livestock farms as an alternative to the currently available methods. Batches of piggery wastewater were treated with this system, and the byproducts of rice straw media and trickling filtrate were applied to the soil with cultivating rye (Secale cereale L.). Objective of this research was to characterize these byproducts for the sustainable soil amendments and rye production. Both the treated straw medium and filtrate were proven to be effective organic fertilizers for rye plant development, with the enhanced but balanced absorption of nutrients. The synergistic effects of filtrate in addition to straw application did not show, but the filtrate appeared to lead to a higher water content of the plant. No specific nutrient deficiency or toxicity symptom was shown due to the salts derived from the byproducts applied. Chemical parameters of the soil quality were significantly improved with the application of straw medium either with or without the filtrate. Judging from parameters relating to the salt accumulations, such as sodium adsorption ratio (SAR), electrical conductivity (EC), exchangeable sodium percentage (ESP), potassium adsorption ratio (KAR), and residual P concentrations, the byproducts from piggery wastewater exhibited no detrimental effects on soil quality within the ranges of treatments used. In addition to the effectiveness of the rice straw trickling filter system for the small-scaled swine farms, both rice straw medium and filtrate could be recycled for the sustainable soil amendment and plant nutrition.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.5 no.2
• /
• pp.217-220
• /
• 2002

Mulberry being a foliage crop is grown extensively for feeding of silkworms and are also used for cattle feeding. These loaves are highly nutritious, which contain various mineral elements and bio-molecules such as carbohydrates, proteins, lipids and other essential amino acids, etc. In the present study, deproteinized mulberry leaf juice was used for preparation of the medium for cultivation of various types of microbes. Results revealed that deproteinized mulberry leaf juice medium is best for isolation of fungi, bacteria and actinomycetes and this medium can be substituted with synthetic media, which are haying the costly ingredients for isolation and identification of bacteria, fungi and actinomycetes. Further, this deproteinized mulberry juice medium can also be used in mass multiplication of useful/beneficial microbes to enhance soil microflora to improve soil fertility and to avoid root diseases. Perspective enterprises can take up the mass multiplication/large-scale production of useful microbes such as Trichoderma, Rhizobium, Pseudomonas and Bacillus to use in mulberry and in other agricultural crops using deproteinized mulberry leaf juice.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.20 no.1
• /
• pp.7-12
• /
• 2010

To determine the optimal isolation conditions of the entomopathogenic fungi from soil, we compared their growth characteristics with non-entomopathogenic fungi on agar media containing various concentrations of cooper (II) chloride ($CuCl_2$) or dodine. The result showed that dodine medium is more selective, and the optimal concentration of dodine is determined with $50{\mu}g$/ml. We could isolate several putative entomopathogenic fungi from soil using this, and identify them using ITS analysis. As a result, 64% fungi were identified as typical entomopathogenic fungi. This selective medium may be useful to the rapid and simple isolation of entomopathogenic fungi from soil.

• Structural Engineering and Mechanics
• /
• v.67 no.3
• /
• pp.311-316
• /
• 2018

Vibration of concrete beams reinforced by agglomerated silicon dioxide ($SiO_2$) nanoparticles is studied based on numerical methods. The structure is simulated by Euler-Bernoulli beam model and the Mori-Tanaka model is used for obtaining the effective material properties of the structure. The concrete beam is located in soil medium which is modeled by spring elements. The motion equations are derived based on energy method and Hamilton's principle. Based on exact solution, the frequency of the structure is calculated. The effects of different parameters such as volume percent of $SiO_2$ nanoparticles and agglomeration, soil medium and geometrical parameters of beam are shown on the frequency of system. The results show that with increasing the volume percent of $SiO_2$ nanoparticles, the frequency increases.

• Proceedings of the KSR Conference
• /
• 2011.05a
• /
• pp.1214-1221
• /
• 2011

It is an well-known fact that dynamic properties should be considered in design and maintenance of civil structures undergoing dynamic force such as rail track. For designing of the rail tack structures, dynamic properties of track bed soil such as shear modulus (G) and damping coefficients(D) obtained in small to medium range of shear strain must be known. In general, small size sample of D=5 cm and H=10cm has been used mostly for test convenience. However, ratio of largest particle diameter of the soil to sample diameter is very important and affects to the values of dynamic soil properties in track bed. In this study, an RC/TS test apparatus was built and was run for testing a medium size soil sample that can handle with compacted soil sample up to 10 cm diameter and 20 cm height.

• Korean Journal of Medicinal Crop Science
• /
• v.14 no.5
• /
• pp.293-298
• /
• 2006

Optimum culture conditions for high frequency plant regeneration from leaf explants of Kalanchoe daigremontiana Hamet &Perrier were established. Shoot regeneration was achieved from leaf explant cultures using MS medium supplemented with indole-3-acetic acid (IAA) and thidiazuron (TDZ) or benzyladenine (BA). Percent regeneration was influenced by plant growth regulators and source of explants. MS medium supplemented with TDZ (1.0 mg/l) and IAA (0.4 mg/l) was the most effective, providing shoot regeneration for 76.7 % of ex vitro leaf explants associated with a high number of shoots per explant (9.5 mean shoots per explant), whereas 100% shoot regeneration associated with 12.4 shoots per explant occurred from in vitro leaf explants on the same medium. Clusters of shoots were multiplied and elongated on MS medium containing several concentrations of BA. MS medium supplemented with 0.25 mg/l BA was proved as the most effective shoot elongation medium. Elongated shoots (2-3 cm) were rooted at 100% on half-strength MS medium. Rooted plantlets were then transferred to potting soil. Regenerated plants were established in the soil with 90% success.

• Korean Journal of Microbiology
• /
• v.47 no.3
• /
• pp.179-187
• /
• 2011

This review describes the characteristics of various unculturable soil bacteria, successfully-cultivating examples of those bacteria, and the diverse factors to be considered for successful cultivation. Most importantly, the selection of proper media is very important because unculturable bacteria demand different types of nutrients at various concentrations of substrates, nitrogens and phosphorus. To develop a new medium to successfully culture unculturable bacteria from soil, molecular ecological studies should be combined together. The inoculum size on a plate is also important: less than 50 bacterial cells are recommended to be plated on a single culture plate. The environmental factors such as pH and salt concentration of the medium need to be adjusted as similar as possible to mimic the original soil environments, and the trial of the various temperatures and extended period of cultivation are better. Since one cannot simply tell about which one was unculturable among a great number of colonies grown on a newly developed medium, some suitable detection methods and fast identification methods are required. Many soil bacteria live with cooperation one another in their communities, so that enrichment such as coculture of using other bacterial metabolites and subsequent pure cultures can also guarantee successful cultivation of the previously uncultured bacteria in soil. Here, this review will discuss for the future perspectives to culture the unculturable soil bacteria.

• Structural Engineering and Mechanics
• /
• v.13 no.6
• /
• pp.615-638
• /
• 2002

This paper presents a method of seismic analysis for a cylindrical liquid storage structure considering the effects of the interior fluid and exterior soil medium in the frequency domain. The horizontal and rocking motions of the structure are included in this study. The fluid motion is expressed in terms of analytical velocity potential functions, which can be obtained by solving the boundary value problem including the deformed configuration of the structure as well as the sloshing behavior of the fluid. The effect of the fluid is included in the equation of motion as the impulsive added mass and the frequency-dependent convective added mass along the nodes on the wetted boundary of the structure. The structure and the near-field soil medium are represented using the axisymmetric finite elements, while the far-field soil is modeled using dynamic infinite elements. The present method can be applied to the structure embedded in ground as well as on ground, since it models both the soil medium and the structure directly. For the purpose of verification, earthquake response analyses are performed on several cases of liquid tanks on a rigid ground and on a homogeneous elastic half-space. Comparison of the present results with those by other methods shows good agreement. Finally, an application example of a reinforced concrete tank on a horizontally layered soil with a rigid bedrock is presented to demonstrate the importance of the soil-structure interaction effects in the seismic analysis for large liquid storage tanks.

• Korean Journal of Soil Science and Fertilizer
• /
• v.48 no.1
• /
• pp.36-43
• /
• 2015

Excess use of chemical fertilizer causes soil acidification and accumulation of salt, and thus might bring to desertification of soil. To overcome this problem, it needs limited usage of chemical fertilizer and increased usage of natural fertilizer as an alternative. In this study, dry soil-borne Bacillus sp. SHL-3, which was isolated from arid and barren soil, with plant growth promoting activity was isolated for identification and to determine optimal culture condition. A bacterial strain SHL-3 had the IAA productivity ($5.16{\pm}0.10mg\;L^{-1}$), ACC deaminase activity ($0.36{\pm}0.09$ at 51 hours) and siderophore synthesis. It was identified as genus Bacillus sp.. Also, optimal culture condition of SHL-3 were $20^{\circ}C$ and pH 7 in LB medium. Bacillus sp. SHL-3 had up to 4% salt tolerance in the medium. We evaluated the plant growth promotion ability of SHL-3 using yam (Dioscorea japonica Thunb.). As a result, Bacillus sp. SHL-3 was effective on the increase of the shoot length (202.4% increase for 91 days). These results indicate that Bacillus sp. SHL-3 can serve as a promising microbial resource for the biofertilizers of soil.