• Journal of Korea Multimedia Society
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• v.19 no.8
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• pp.1275-1280
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• 2016

This research is for the visualization of wooden cracking phenomena in the virtual world. Timber supplies has been traditionally used for buildings in the all over the world. Wood has a characteristic that is more prone to be influenced and distorted under the external environments compared with other materials like as stone and concrete. Many related researches say that moisture content change is a largest impact factor for the distortion and crack of timber supplies. This is the reason why we focus on the relationship between the moisture variations and the wood distortion, especially crack. In this research, it is mathematically explained that the diminutions of tensile strength caused by repeated contraction and expansion according to the moisture variations under the changes of weather. Finally, we suggest a way to visualize it for pine timbers.

• Korean Journal Plant Pathology
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• v.13 no.2
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• pp.100-104
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• 1997

Influence of the moisture content in soils was examined on population variations of soil microbes, including Cylindrocarpon destructans causing root rot of ginseng, in vivo and under the field condition. Fungal populations decreased in soils treated with various moisture contents in vivo as days after the treatment in creased, but there was not a significant difference in the population among other treatments except 135% moisture content (flooding) at 15 weeks after the treatment. In flooded soils populations of total fungi and C. destructans were reduced to 1/10 and 1/50 of initial populations, respectively. There was, however, a little difference in the population of total bacteria or Actinomycetes between before and at 15 weeks after flooding. On the other hand, population variations of bacteria and Actinomycetes were much greater than those of fungi at different intervals after the moisture treatment. Variations of microbial populations in flooded soils under the field condition were similar to those in vivo. Especially, populations of Fusarium and pectolytic bacteria in flooded soils were reduced to 1/100 of populations in nonflooded soils at 170 days after treatment.

• Journal of the Korea Furniture Society
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• v.10 no.2
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• pp.29-36
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• 1999

During a radio-frequency/vacuum plus press drying process of some hardwood veneers for decoration we investigated the effect of a grain and thickness of a veneer sheet on drying rates, variations of final moisture content within a bundle of veneer sheets, and formation of checking, end waving, and burning mark. About thirty three hundreds sheet of veneer could be dried in sixty five hours from green to in0-use moisture content, and a final moisture content was significantly effected by initial moisture content of veneer. There were nearly variations in a final moisture content among the veneer sheets in the same bundle. A checking was never found in a edge-sliced veneer, and very slight in a flat-sliced veneer of ash and red oak. There were no end waving and no burning mark in all veneer sheets.

• Korean Journal of Soil Science and Fertilizer
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• v.48 no.6
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• pp.571-581
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• 2015

Soil moisture content is generally accepted as an important factor to understand the process of crop growth and is the basis of earth system models for analysis and prediction of the crop condition. To continuously monitor soil moisture changes at kilometer scale, it is demanded to create high resolution data from the current, several tens of kilometers. In this paper we described a downscaling method for Advanced Microwave Scanning Radiometer 2 (AMSR2) Soil Moisture Content (SMC) from 10 km to 30 m resolution using a soil texture and field measurements that have a high correlation with the SMC. As a result, the soil moisture variations of both data (before and after downscaling) were identical, and the Root Mean Square Error (RMSE) of SMC exhibited the low values. Also, time series analyses showed that three kinds of SMC data (field measurement, original AMSR2, and downscaled AMSR2) had very similar temporal variations. Our method can be applied to downscaling of other soil variables and can contribute to monitoring small-scale changes of soil moisture by providing high resolution data.

• Journal of Korea Water Resources Association
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• v.35 no.1
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• pp.65-75
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• 2002

The objectives of this study are to analyse model-based soil moisture variations depending on model parameters m and $T_0$ and to evaluate the model performance for the simulation of soil moisture variations by the comparison of observed groundwater levels and model-driven soil moisture amounts and observed and simulated river discharges at the basin outlet. The selected study area is the Pyungchang IHP river basin with outlet at Sanganmi station and the summer flooding events during '94-'98 are used for the analysis. As a result, soil moisture holding capacity is increased according to increase the parameter m that represents effective groundwater depth. This phenomenon is especially dominant when higher m and $T_0$ values are used. The qualitative comparison of computed base flow and observed groundwater level shows that the base flow peaks are reasonably simulated and the decreasing limbs of hydrograph are mainly caused by base flows. It is concluded that TOPMODEL can be used effectively for simulating basin-averaged soil moisture variations in addition to river flow generations.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.E
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• pp.9-17
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• 1998

Oxides of nitrogen play important roles in atmospheric chemistry. Soil has been recognized as a major natural source of NO, and its emission depends on soil parameters such as soil nitrogen availability, soil moisture and temperature. It is necessary to understand effects of these controlling parameters on soil NO emission. In order to understand soil moisture effects on NO emission, variations of NO concentration and existence of its equilibrium concentration were observed from ammonium fertilized Japanese upland soil prepared for different soil moisture conditions. The closed chamber technique was employed for this study. The significant increases in NO with soil moisture were found. Maximum was occurred at sample ID4 (55% of water-filled pore space (WFPS)), but it decreased as soil moisture increased. No significant NO concentration was emitted from soil sample without fertilizer, but there was significant NO in fertilized soil samples. The magnitudes of NO from soil increased with time and reached at steady state within ten minutes approximately. These results suggest that nitrogen input from fertilizer takes charge in the first step of sharp increase in NO emission, and then soil moisture becomes important factor to control NO emission from the soils. NO concentrations from soil were compared to those one-day after the experiment. Results from the comparison analysis suggest that the soil NO flux might have been stimulated by soil disturbances like mixing, and this is much more effective in dry soils rather than in wet soils. It was found that much less NO came out from soils after a day; suggesting that most of NO was released from the soils within a day after fertilizer application during our experiment. The length of NO releasing time span may depend on the amounts of fertilizer applied, soil moisture condition, and other soil physical parameters.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.526-528
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• 1999

Epoxy resin has been used as matrix resin of advanced composites owing to ideally suitable properties and inherent physical and chemical properties for electrical and electronic insulation In this paper, in order to evaluate the performance of epoxy composites for out door insulation, variations of tracking resistance were investigated on the moisture absorption aging condition. Also, IPN methods were introduced in order to improve performance for out door use. As a result, it was confirmed that tracking resistance were degraded with boilling time. But, it was confirmed that specimen of IPN structure and KC-335 have the better tracking resistance properties than SIN structure by moisture absorption aging

• Journal of the Korean Society for Precision Engineering
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• v.16 no.7
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• pp.158-167
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• 1999

Heat and moisture transfer associated with porous materials are investigated. The heat and moisture transfer in porous materials caused by the interaction of moisture gradient, temperature gradient, conduction, and evaporation are considered. The variations of temperature and moisture not only change the volume but also induce the hygro-thermal stress. The finite element formulation for solving the temperature and moisture transfer as well as the associated hygro-thermal stresses is developed. In order to verify the finite element formulation, the heat and moisture moving boundary problem in a half space and the hygro-thermo-mechanical problem in an infinite plate with a circular hole are analyzed. Temperature profile, moisture profile, and hygro-thermal stresses are compared with those of analytic solution and other investigator. Good agreements are examined

• Smart Structures and Systems
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• v.6 no.9
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• pp.1007-1023
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• 2010

This paper describes the development and evaluation of an innovative TDR distributed moisture sensor. This sensor features advantages of being responsive to the spatial variations of the soil moisture content. The geometry design of the sensor makes it rugged for field installation. Good linear calibration is obtained between the sensor measured dielectric constant and soil physical properties. Simulations by the finite element method (FEM) are conducted to assist the design of this sensor and to determine the effective sampling range. Compared with conventional types of moisture sensor, which only makes point measurement, this sensor possesses distributed moisture sensing capability. This new sensor is not only easy to install, but also measures moisture distribution with much lower cost. This new sensor holds promise to significantly improve the current field instruments. It will be a useful tool to help study the influence of a variety of moisture-related phenomena on infrastructure performance.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.29-32
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• 2002

In order to investigate effect of irrigation on soil moisture and soybean growth, a experimental plot, which was shielded from precipitation was established. Four different irrigation rates were applied and soil moisture variations were monitored with TDR. Soybean yield and product quality are under scrutiny.