• Journal of the Institute of Electronics and Information Engineers
• /
• v.50 no.10
• /
• pp.245-251
• /
• 2013

An impedance of ground electrode for information and communication facilities has a significant relationship with the electrical characteristics of soil where the ground electrode is buried. Especially, the impedance of ground electrode is directly affected by the characteristics of permittivity and conductivity in soil as a function of a frequency of an applied electric field. The program based on the electromagnetic field model was developed in MATLAB. Because both permittivity and conductivity can not be modified in commercial programs. The permittivity of soil was applied with the Debye equation which is a model of dielectric relaxation. And the empirical equation of the conductivity in soil was quoted in other paper. In order to confirm the reliability of proposed program, the impedance measurement of ground electrode was carried out, which were compared with the results of simulation in commercial program. In result, it was confirmed that the impedance and phase different simulated by appling the characteristics of permittivity and conductivity in soil are in good agreement with the measured values than results of NEC.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.17 no.2
• /
• pp.213-226
• /
• 2019

Regulatory agency and licensee are preparing for the site restoration of Kori unit 1, the first commercial NPP in Korea, scheduled for 2031. Developing regulatory guidelines and strategies is essential for effective restoration work. Unfortunately, Korea does not have experience of site restoration of commercial NPPs. Therefore, it is important to review cases from experienced countries to establish a strategy and regulatory standards. The U.S. has had numerous soil remediation experiences using RESRAD and MARSSIM. However, formalized evaluation methodologies for subsurface soil have not yet been established in MARSSIM. This survey focused on subsurface soil remediation by reviewing the five decommissioned NPPs under regulation of the US NRC. Overall process of remediating a contaminated subsurface soil and groundwater was reviewed to identify considerations and lessons that could be applicable in Korea. In addition, an applied methodology for evaluation of contaminated subsurface soil and related major issues between regulatory agency and licensees were reviewed in detail to support establishment of remediation strategy for Kori unit 1.

• Korean Journal of Soil Science and Fertilizer
• /
• v.44 no.6
• /
• pp.1181-1184
• /
• 2011

Total aerobic bacteria, Esherichia coli O157:H7, and Salmonella spp. were examined in commercial liquid pig manures. Commercial liquid pig manures (n=33) were collected from muck joint resource recovery plant at April, June, August, October 2009, Korea. Total aerobic bacteria were incubated at $37^{\circ}C$ for 24-48 hrs, and quantified as a colony-forming unit (CFU) $mL^{-1}$. Analysis of Esherichia coli O157:H7 and Salmonella spp. were followed by Korean Food Standards Codex method. Colony of Salmonella spp. was confirmed by API kit and real time polymerase chain reaction (PCR). Total aerobic bacteria isolated from fermented commercial liquid pig manures ranged from 2.8 to $24.3{\times}10^4\;CFU\;mL^{-1}$. Esherichia coli O157:H7 was not detected, and Salmonella spp. showed the low detection frequency at only 1 sample. This study suggests that continuous monitoring in commercial liquid pig manures is required to improve the agricultural food through management of agricultural land contaminated with liquid pig manures.

• Journal of Soil and Groundwater Environment
• /
• v.26 no.6
• /
• pp.157-164
• /
• 2021

Smart agriculture requires sensing systems which are fundamental for precision agriculture. Adequate and appropriate water and nutrient supply not only improves crop productivity but also benefit to environment. However, there is no available soil sensor to continuously monitor nutrient status in soil. Electrical conductivity (EC) of soil is affected by ion contents in soil and can be used to evaluate nutrient contents in soil. Comparison of various commercial EC sensors showed similar water content and EC values at water content less than 20%. Soil EC values measured by sensors decreased with decreasing soil water content and linearly correlated with soil water content. EC values measured by soil sensor were highly correlated with water soluble nutrient contents such as Ca, K, Mg and N in soil indicating that the soil EC sensor can be used for monitoring changes in plant available nutrients in soil.

• Journal of Soil and Groundwater Environment
• /
• v.15 no.3
• /
• pp.7-14
• /
• 2010

Ecological Risk Assessment (ERA) supports a decision-making process such as establishment of environmental quality criteria. Soil quality criteria (SQC) are essential to protect soil organisms from the exposure to various soil contaminants. In this study, ERA methodologies of advanced countries for soil pollution were extensively compared to propose the ERA approach suitable for soil ecosystem in Korea. The soil ERAs in European Chemical Bureau(ECB), The Netherlands, and Canada can be classified as deterministic ecological risk assessment (DERA), and probabilistic ecological risk assessment (PERA) based on species sensitivity distribution (SSD). We propose three ERA methods according to abundance and reliability of soil ecotoxicity data. The method considered land use such as residential/agricultural, and industrial/commercial uses. The taxonomic groups of soil organism were classified as 'Class' level including different trophic levels (Magnoliopsida or Liliopsida, Clitellata, and Insecta or Secernentea). This study can be used to estimate the soil quality criteria to protect soil biota.

• Journal of Environmental Science International
• /
• v.30 no.12
• /
• pp.1015-1025
• /
• 2021

Our research work aimed to evaluate cover crop effects of winter rye on soil characteristics, soil conservation, and yield productivities on potato fields with 15% slope during a fallowed period. There were two controls of bared field without any cultivation and conventional potato cultivation without winter rye. Potato cultivation increased soil pH, organic matter, available phosphate, and exchangeable cation regardless of cover crop cultivation. Sub-soil, particularly, all components of soil chemical properties showed higher value in winter rye cultivation than conventional cultivation. Higher soil density was observed on cover crop cultivation than conventional cultivation resulting from root residues of the cover crop both topsoil and subsoil. Cover crop residues positively affected plant growth and reduced the amount of soil erosion by holding the soil. Although severe soil erosion was seen in conventional cultivation, winter rye cultivation declined soil erosion by 47% during the fallow period on potato slope fields. Distinct soil bacterial communities were detected among treatments and some OTU(Operational Taxonomic Unit)s showed significantly higher abundance in winter rye treatment. Total yield and commercial rate demonstrated no significant differences while higher tuber phosphate, K⁺, and Mg²⁺ contents were observed in winter rye cultivation.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.47 no.2
• /
• pp.353-370
• /
• 2023

In this study, the performance of ultrasonic cleaners for ultrasonic washing, which is one of the wet cleaning methods, was evaluated. The washing performances of ultrasonic cleaners were compared with commercial washing machines under normal and wool courses based on different parameters such as detergency, wrinkle formation, fabric damage, dimensional stability, and germ removal ability. Cotton, silk and wool were used in this experiment. Results revealed that the ultrasonic washing detergency of cotton fabrics was lower than that of commercial washing machines under the normal course and similar to that of commercial washing machines under the wool course. Detergency of silk fabrics was similar under both normal and wool courses. In terms of wrinkle formation and dimensional stability, ultrasonic cleaners showed lesser wrinkles and lower shrinkage than commercial washing machines. Considering damage evaluation, ultrasonic cleaners more effectively removed soil without damaging fabrics compared with commercial washing machines. The bacteria removal rate of both cotton and silk was more effective than the wool course of a commercial washing machine. Thus, this study compares the performance of ultrasonic cleaners and commercial washing machines and provides meaningful results related to ultrasonic washing performance.

• Journal of Environmental Science International
• /
• v.18 no.9
• /
• pp.993-1000
• /
• 2009

The development of a new type of soil-cement concrete pavement using volcaniclastic is the main purpose of this study. Various mixture ratios, specimens' penetration resistance, time of setting, slump flow of fleshly mixed concrete, compressive strength and color characteristics of hardened concrete were studied. It was concluded that the optimum weight ratio of cement:volcaniclastic to produce good properties of soil-cement concrete is 1:3 and the use of volcaniclastic as main aggregate can improve the concrete surface color that is warm earth-tone road color. Therefore, commercial development for soil-cement concrete pavement using volcaniclastic is highly promising.

• Journal of Ocean Engineering and Technology
• /
• v.21 no.1 s.74
• /
• pp.69-74
• /
• 2007

This paper is concerned about the dynamic analysis of an underwater test miner, which operates on cohesive soil. The test miner consists of tracked vehicles and a pick-up device. The motion of the pick-up device, relative to the vehicle chassis, is controlled by two pairs of hydraulic cylinders. The test miner is modeled by means of commercial software. A terramechanics model of cohesive soft soil is implemented with the software and applied to a dynamic analysis of the test miner model. The dynamic responses of the test miner are studied with respect to four different types of terrain conditions.

• Korean Journal of Agricultural Science
• /
• v.37 no.3
• /
• pp.413-433
• /
• 2010

South Dakota is an important agricultural state in the United States with annual cash receipts from agricultural products exceeding $9 billion dollars. This production is possible because of large areas of productive soils. This publication describes the general characteristics and qualities of the major soil groups recognized in South Dakota. The soil forming factors are briefly described, soil classification is introduced, and the genesis of typical Udalf and Ustoll soils are discussed. Soil management issues impacting the use of SD soils are considered. Long-term (>70 yrs) cultivation has significantly reduced surface soil organic carbon levels (>30% reduction) when compared to non-cultivated soil. Soil test phosphorus levels significantly increased in cultivated fields due to commercial P fertilization. The major long-term production problems for SD soils are conservation of soil moisture, organic matter and nitrogen losses, fertility management, and wind and water erosion control.