• Microbiology and Biotechnology Letters
• /
• v.22 no.5
• /
• pp.561-563
• /
• 1994

For the more effective isolation of soil actinomycetes, we have developed HHV (Hair hydrolysate-vitamin) agar medium, containing hair as the sole source of carbon and nitrogen. The HHV agar medium was superior to other media such as colloidal chintin agar, glycerol-arginine agar and starch-casein-nitrate agar, and HV (humic acid-vitamin) agar. The maximum effect of this medium has been shown in hair dry weight 0.4 g/l medium. Of each soil sample, the greatestest number of actinomycetes was isolated from the potato annual planted soil among the tested samp- les. The genus of actinomycetes isolated from the potato annual planted soil sample was identified such 5 group as Stretomyces, Micromonospora, Microbispora, Nocardia and Saccharopolyspora.

• Computers and Concrete
• /
• v.22 no.2
• /
• pp.221-225
• /
• 2018

In this paper, vibration analysis of concrete foundations resting on soil medium is studied. The soil medium is simulated by Winkler model considering spring element. The concrete foundation is modeled by thick plate elements based on classical plate theory (CPT). Utilizing energy method consists of potential energy, kinetic energy and external works in conjunction with Hamilton's principle, the motion equations are derived. Assuming the simply supported boundary condition for the concrete foundation, the Navier method is used for calculating the frequency of the structure. The effect of different parameters such as soil medium, mode numbers, length to width ratio and length to thickness ratio of the concrete foundation are shown on the frequency of the structure. At the first, the results are validated with other published works in order to show the accuracy of the obtained results. The results show that considering the soil medium, the frequency of the structure increases significantly.

• Structural Engineering and Mechanics
• /
• v.51 no.5
• /
• pp.727-741
• /
• 2014

The functionally graded beam (FGB) is investigated in this study on both dynamic and static loading in case of resting on a soil medium rather than on the usual Winkler-Pasternak elastic foundation. The powerful ABAQUS software was used to model the problem applying finite element method. In the present study, two different soil models are taken into account. In the first model, the soil is assumed to be an elastic plane stress medium. In the second soil model, the Drucker-Prager yield criterion, which is one of the most well-known elastic-perfectly plastic constitutive models, is used for modelling the soil medium. The results are shown to evaluate the effects of the different soil models, stiffness values of the elastic soil medium on the normal and shear stress and free vibration properties. A comparison was made to those from the existing literature. Numerical results show that considering real soil as a continuum space affects the results of the bending and the modal properties significantly.

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.48 no.3
• /
• pp.238-242
• /
• 2003

Reclaimed tidal areas for rice cultivation are irrigated with salt mixed water when there is severe drought. Therefore, we identified the critical concentration of saline water for rice growth on a reclaimed saline soil in Korea. The experiment was conducted at the Kyehwado substation of the National Honam Agricultural Experiment Station (NHAES) during 2001-2002. Two experimental fields with 0.1-0.2% for low soil salinity and 0.3-0.4% for medium soil salinity levels were used. The experiment involved four levels of salt solution mixed with sea water (at 0.1, 0.3, 0.5, 0.7%) compared with a control using tap water in a split-plot design with three replicates. Saline solution was applied only two times at seedling stage (10 DAT and 25 DAT) for 5 days. Gyehwabyeo and dongjinbyeo, japonica rice varieties, were used in this experiment. Plant height and number of tillers sharply decreased in the 0.5% saline water in low soil salinity level and 0.1% in medium soil salinity level. For yield components, panicle number per unit area and percentage of ripened grain dramatically decreased in the 0.5% saline water in low soil salinity and 0.1% in medium soil salinity level. But 1,000-grain weight of brown rice decreased sharply in the 0.5% saline water in low soil salinity and 0.3% in medium soil salinity, indicating that this component was not much affected unlike other yield components. Milled rice yield decreased significantly with saline water level in both low and medium soil salinity. In the 0.7% low saline soil, the yield index was only 36% compared with the control. In medium soil salinity, even the control plot showed only 62% yield index compared with the control in the low soil salinity treatment. Results indicated that the critical concentration of saline water for rice growth in terms of economical income of rice production was 0.5% in low soil salinity and tap water in medium soil salinity.

• Journal of Biosystems Engineering
• /
• v.2 no.1
• /
• pp.25-32
• /
• 1977

This experiment was conducted in order to find out the drawing performance of a two-wheel tractor under different levels of the soil moisture and hardness, so as to obtain some basic data for improving their drawing performance. With fairly homogeneous soil, 5 levels of soil moisture contents (8, 13, 17, 20 and 23%) and 3 levels of soil hardness (0 , 2 and 4kg/$cm^2$) were selected for this experiment.The summerized results are as follows ;1. The draft force, on the hard soil (hardness ; 4kg/$cm^2$), had a distinct tendency to decrease with the increasing soil moisture. On the medium soil (hardness ; 2 kg/$cm^2$), and the soft soil (hardness ; 0kg$cm^2$), the draft force showed the highest when the moisture contents were within the range of 16-19%.But the maximum draft force, on the soft soil, was higher than that on the medium soil by 10 %. 2. The driving axle torque increased with increasing soil by 10 %. 3.The values of horizontal distance between the soil reaction point and axle shaft were within the range of 0~10cm , and it had the tendency to increase with the increasing soil moisture. Also, it s value was the largest on the hard soil and the smallest on the soft soil. 4.The tractive efficiency decreased with the increasing soil moisture. On the hard soil, the average value of tractive efficiency was higher than that on the medium soil by 19.0% and that on the soft soil was lower than that on the medium soil. 5.The traction ratio were within the range of 30 ~45%, and their changing tendency with respect to the soil moisture was similar to that in the case of the draft force. 6. The travel resistance ratio tended to increased with increasing soil moisture, and the highest value was found on the soft soil, and the lowest on the hard soil.

• Journal of the Korean Wood Science and Technology
• /
• v.46 no.6
• /
• pp.645-655
• /
• 2018

The use of wood waste as substrate for plant growth exemplifies a strategy for turning waste into resources. The overall objective of this research was to evaluate the effects of wood-based growing media on plant cover in a slope area. Moreover, we tried to find out what physicochemical properties affect plant cover on a slope. For treatments, we tested natural soil, soil mixed with wood-based growing medium (1:1, w/w), and wood-based growing medium by itself. Physical and chemical characteristics were evaluated after four months from the date of treatment application to the experimental slope site. Soil coverage with seedlings of Lespedeza cyrtobotrya was measured for plant growth evaluation. Physicochemical properties were altered by mixing the natural soil with wood-based growing medium. Particularly, soil moisture and organic matter contents were significantly changed in soils treated with wood-based growing medium compared to soil alone. We confirmed that plant coverage rate was high when wood-based growing medium was mixed with the natural soil. There was a significant linear relationship between moisture content and CEC (Cation Exchange Capacity) of all growth media tested and plant coverage. This result was expected, as moisture content tends to increase with organic matter content, such as in wood-based growing medium. In conclusion, the high moisture content of the wood-based growing medium was considered effective for plant growth in the experimental slope site, and this wood-based growing medium provides a means to improve the harmony between the slope and the surrounding environment.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2000.11c
• /
• pp.757-763
• /
• 2000

It is fundamental to control individual condition of every seedling. Automatic individual control is used by data control and analysis at on-line. As a result the best condition system was build without all waste. This system uses one of new technology irrigation system. This irrigation system supply accurate quantity of nutrient solution in the shortest time. The system named the upward injection irrigation system. First of all it is necessary to be considered whether the soil is proper or improper for upward injection irrigation system. It is important that root absorb nutrient solution as fast as possible. The ability of spreading, storing water, contamination of environment and cost were considered when choose the medium. The soil of organic culture is developed recently. The soil consists of paper pulp and vermiculite. The new soil is more suitable than ordinary medium for growing plant because this medium is made of paper pulp. The ability of store and spread of water is it's feature. We can make paper tray of this paper pulp's raw material. It is possible that pulp tray replaced plastic tray. The original plug tray of growing seedling system can make which consist of pulp medium and pulp tray. In this study, it was examined whether the plug seedling of paper pulp medium grow with upward injection irrigation system in this seedling plant system. At the same time, examine ability of store and spread of water and how to grow plant on the paper pulp medium.

• The Plant Pathology Journal
• /
• v.30 no.4
• /
• pp.432-436
• /
• 2014

The soil-borne ascomycete fungus Cylindrocarpon destructans causes ginseng root rot disease and produces various secondary metabolites such as brefeldin A and radicicol. The slow growth of this fungus compared with other plant pathogenic and saprophytic fungi in soil disturbs isolation of this fungus from soil and infected ginseng. In this study, we developed a selective medium for C. destructans using radicicol produced by this fungus. Supplementing 50 mg/L of radicicol to medium inhibited the mycelia growth of other fungi including Botrytis cinerea, Rhizoctonia solani and Alternaria panax, but did not affect the growth of C. destructans. In addition, conidia germination of other fungal species except for C. destructans was inhibited in submerged culture supplemented with radicicol. This medium provides a very efficient tool for isolating C. destructans and also can be used as an enrichment medium for this fungus.

• Structural Engineering and Mechanics
• /
• v.64 no.6
• /
• pp.703-721
• /
• 2017

The experimental study of the behavior of dry medium and loose sandy soil under the action of a single impulsive load is carried out. Different falling masses from different heights were conducted using the falling weight deflectometer (FWD) to provide the single pulse energy. The responses of soils were evaluated at different locations (vertically below the impact plate and horizontally away from it). These responses include; displacements, velocities, and accelerations that are developed due to the impact acting at top and different depth ratios within the soil using the falling weight deflectometer (FWD) and accelerometers (ARH-500A Waterproof, and Low capacity Acceleration Transducer) that are embedded in the soil and then recorded using the multi-recorder TMR-200. The behavior of medium and loose sandy soil was evaluated with different parameters, these are; footing embedment, depth ratios (D/B), diameter of the impact plate (B), and the applied energy. It was found that increasing footing embedment depth results in: amplitude of the force-time history increases by about 10-30%. due to increase in the degree of confinement with the increasing in the embedment, the displacement response of the soil will decrease by about 25-35% for loose sand, 35-40% for medium sand due to increase in the overburden pressure when the embedment depth increased. For surface foundation, the foundation is free to oscillate in vertical, horizontal and rocking modes. But, when embedding a footing, the surrounding soil restricts oscillation due to confinement which leads to increasing the natural frequency, moreover, soil density increases with depth because of compaction, that is, tendency to behave as a solid medium.

• Steel and Composite Structures
• /
• v.27 no.4
• /
• pp.465-477
• /
• 2018

In this research, vibration and smart control analysis of a concrete foundation reinforced by $SiO_2$ nanoparticles and covered by piezoelectric layer on soil medium is investigated. The soil medium is simulated with spring constants and the Mori-Tanaka low is used for obtaining the material properties of nano-composite structure and considering agglomeration effects. With considering first order shear deformation theory, the total potential energy of system is calculated and by means of Hamilton's principle in three displacement directions and electric potential, the six coupled equilibrium equations are obtained. Also, based an analytical method, the frequency of system is calculated. The effects of applied voltage, volume percent and agglomeration of $SiO_2$ nanoparticles, soil medium and geometrical parameters of structure are shown on the frequency of system. Results show that with applying negative voltage, the frequency of structure is increased.