• International Journal of Highway Engineering
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• v.13 no.2
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• pp.139-145
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• 2011

The practice of asphalt pavement recycling has grown rapidly over the decade, one of which is the cold in-place recycling with the foamed asphalt (CIR-foam) or the emulsified asphalt (CIR-emulsion). Particularly, in Iowa, the CIR has been widely used in rehabilitating the rural highways because it significantly increases the service life of the existing pavement. The CIR layer is typically overlaid by the hot mix asphalt (HMA) to protect it from water ingress and traffic load and obtain the required pavement structure and texture. Most public agencies have different curing requirements based on the number of curing days or the maximum moisture contents for the CIR before placing the overlay. The main objective of this study is to develop a moisture loss index that the public agency can use to monitor the moisture content of CIR layers in preparation for a timely placement of the wearing surface. First, the moisture contents were measured in the field using a portable time domain reflectometry (TDR) device. Second, the weather information in terms of rain fall, air temperature, humidity and wind speed was collected from the same location. Finally, a moisture loss index was developed as a function of initial moisture content, air temperature, humidity and wind speed. The developed moisture loss index based on the field measurements would help the public agency to determine an optimum timing of an overlay placement without continually measuring moisture conditions in the field.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.84-88
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• 2009

토양수분은 물순환계통을 이해하기 위한 필수적인 수문학적 변수이나 설치비용과 인력부족으로 실측자료가 매우 부족한 실정이다. 많은 수문모형의 개발로 토양수분 또한 결과물로써 많이 이용되지만, 그 결과의 신뢰성을 판단하기가 쉽지 않다. 본 연구에서는 활용성이 높다고 판단되는 수문모형인 SWAT 모형을 통해 산림지역의 토양수분을 모의하고 MODIS NDVI와의 상관성을 분석하여, 모의된 토양수분의 신뢰성 판단을 위한 MODIS NDVI의 활용성을 파악하고자 하였다. 대상유역은 산림이 전체유역의 약 82%를 차지하고 있는 충주댐 유역으로 하였으며 NDVI 자료는 시간해상도 16일, 공간해상도 250m 인 MODIS 영상의 Product를 이용하였다. 보다 신뢰성 있는 자료를 얻기 위해 유역의 특성이 다른 두 지점을 선정하여 다지점 검보정을 수행하였으며, 2003년부터 2006년까지의 유출 자료를 이용하여 모형을 보정하고, 2000, 2001 그리고 2002년에 대하여 검증하였다. 검보정 결과 모형 효율성 계수는 상류와 하류에 대하여 각각 0.91, 0.87, 결정계수는 각각 0.90, 0.80으로 분석되었다. 본 연구에서는 NDVI 특성에 따라 봄 기간과 가을기간으로 나누어 분석을 수행하였으며, NDVI와 토양수분의 상관관계는 NDVI가 증가하는 봄 기간에 토양수분은 감소하며 역 관계로 나타났고 NDVI가 감소하는 가을 기간에 토양수분은 증가하는 순 관계를 보였다.

• Journal of The Korean Society of Grassland and Forage Science
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• v.11 no.4
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• pp.209-214
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• 1991

The germination of seeds is developmentally complex process requiring water uptake, which is regulated by both genotypic and environmental factors. The present study was undertaken to determine the difference in germination characteristics, and to compare the ability of the logistic and Weibull functions to describe the cumulative germination curve when two levels of osmotic potential(0, -5 bar) were put to seeds of alfalfa, tall fescue, orchardgrass, and Kentucky bluegrass. The effects of grass type, osmotic potential, and their interaction on the total germination and coefficient of germination velocity were significant(P<0.01). The Weibull equation for predicting percent cumulative germination curve of alfalfa had significantly lower residuals than the logistic equation regardless of osmotic potential(P<0.01), indicating that the Weibull equation was more efficient than the logistic equation to fit the data of the percent cumulative germination of alfalfa. The rate parameter from the logistic equation was decreased under water stress, whereas the scale and shape parameters were increased. There were significant differences in days to 20% germination estimated from the logistic and Weibull equations.

• Korean Journal of Soil Science and Fertilizer
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• v.23 no.1
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• pp.8-14
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• 1990

Retardation and hydrodynamic dispersion coefficient necessary for model of water and solute movement in a soil were determined for horizontal soil column with different initial soil water conditions. The soil columns were compacted with sandy loam soil. The bulk density was $1,350+50kg/m^3$, and initial water contents were 0.05, 0.08 and 0.14. Advancement of 0.05% $CaSO_4$ solution was used as the standard and advancements of 0.5% KCl, $CaCl_2$ and $KH_2PO_4$ were compared. Retardation of non-reactive $Cl^-$ was related with the initial soil water content, ${\theta}n$, as ${\theta}/({\theta}-{\theta}n)$, and anion exclusion was ignored. Retardations of active $K^+$, $Ca^{{+}{+}}$ and $H_2PO_4{^-}$ were related as 1/(R+1) $^*{\theta}/({\theta}-{\theta}n)$, in which R was retardation coefficient. Measured R was 0.64 for $K^+$, 0.80 for $Ca^{{+}{+}}$ and 2.6 for $H_2PO_4{^-}$, respectively. Calculated R using Langmuir adsorption isotherm showed fair degree of applicability. Soil water diffusivity, $D({\theta}),m^2/sec$, calculated for different initial water content showed unique function as $$log(D({\theta}))=13.448{\theta}-9.288$$ Hydrodynamic dispersion coefficient of $Cl^-$ above soil water content 0.36 was similar to soil water diffusivity and decreased to near self diffusion coefficient at soil water content near 0.2. Those of $K^+$, $Ca^{{+}{+}}$ $H_2PO_4{^-}$ at soil water content of 0.38 were $5.5{\times}10^{-6}$, $2.4{\times}10^{-6}$ and $7.1{\times}10^{-7}m^2/sec$ and decreased rapidly with decreasing soil water content lower than 0.36.

• Korean Journal of Food Science and Technology
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• v.49 no.4
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• pp.444-452
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• 2017

This study aims to investigate the physicochemical properties of the extruded rice snack with added the containing mealworm. Adding the mealworm addition enhanced protein and unsaturated fatty acid contents, which are insufficient in rice. As the extrusion process variables, the death temperatures and moisture content were set to at respective 130 and $140^{\circ}C$, and 20 and 25%, respectively. The expansion ratio increased as with death temperature, whereas the increased moisture content decreased. The nitrogen solubility index and protein digestibility index increased with the added mealworm content of mealworm increased. As mealworm content and death temperature, and moisture content increased, DPPH radical scavenging activity significantly increased but the rancidity decreased. As the result of this study, confirmed that the addition of mealworm to the extruded rice snack was the confirmed as the effective process to improve nutrition, and antioxidation. Also, death temperature and moisture content have an effect on softened the texture of extruded rice snack.

• Magazine of the Korea Concrete Institute
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• v.8 no.5
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• pp.135-143
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• 1996

Diffusion of water in hardened cement concrete and mortar influences on the dry shrinkage. creep. modulus of' elasticity, etc. In general, water loss through drying process in polymer-modified concrete and mortar is small compared with that of unmodified concrete and mortar due to the films formed by polymer as cement modifieder. The purpose of this study is to investigate the diffusion process of water in the polymer-modified mortars. The polymer-modified mortars using three polymer dispersions and epoxy resin are prepared with various polymer-cement ratios, and water diffusion coefficient of polymer-modified mortars according to inside water content is calculated. From the test results, the water diffusion coefficient of polymer modified mortars i s smaller than that of unmodified mortars and decreases with increasing polymer cement ratio.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2369-2379
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• 2013

The Soil-Water Characteristics Curve (SWCC) is affected by the initial density of soil under unsaturated condition. Also, the characteristic of hydraulic conductivity is changed by the initial density of soil. To study the effect of initial density of unsaturated soil, SWCC and the Hydraulic Conductivity Function (HCF) of Jumoonjin sand with various relative densities, 40%, 60% and 75% were measured in both drying and wetting processes. As the results of SWCC estimated by van Genuchten (1980) model, the parameter related to Air Entry Value(AEV), ${\alpha}$ in the wetting process is larger than that in drying process, but the parameters related to the SWCC slope, n and the residual water content, m are larger than those in wetting process. The AEV is increased or Water Entry Value (WEV) is decreased with increasing the relative density of sand. The AEV is larger than the WEV at the same relative density of sand. As the results of HCF estimated by van Genuchten (1980) model which is one of the parameter estimation methods, the unsaturated hydraulic conductivity maintained at a saturated one in the low level of matric suctions and then suddenly decreased just before the AEV or the WEV. The saturated hydraulic conductivity in drying process is larger than that in wetting process. The saturated hydraulic conductivity is decreased with increasing the relative density of sand in both drying and wetting processes. Also, the hysteresis in unsaturated HCFs between drying and wetting process was occurred like the hysteresis in SWCCs. According to the test results, the AEV on SWCC is decreased and the saturated hydraulic conductivity is increased with increasing the initial density. It means that SWCC and HCF are affected by the initial density in the unsaturated soil.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.39 no.2
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• pp.139-145
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• 1994

This study was intended to obtain the basic information on the germination status, changes of $\beta$-amylase activity and reducing sugar contents during seed germination of barley after an imposition of water stress by adding Polyethylene glycol solution. The effects of water deficit on germination were to be decreased in germination rate and velocity. Respiratory Quotient was increased as the osmotic potential in culture solution was decreased. But $\beta$-amylase activity and reducing sugar contents were decreased and the ratio of dry to fresh weight of germinated seeds was increased as the osmotic potential of the culture solution was decreased.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.127-134
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• 2012

Microwave remote sensing can help monitor the land surface water cycle, crop growth and soil moisture. A ground-based polarimetric scatterometer has an advantage for continuous crop using multi-polarization and multi-frequencies and various incident angles have been used extensively in a frequency range expanding from L-band to Ka-band. In this study, we analyzed the relationships between L-, C- and X-band signatures and soil moisture content over the whole soybean growth period. Polarimetric backscatter data at L-, C- and X-bands were acquired every 10 minutes. L-band backscattering coefficients were higher than those observed using C- or X-band over the period. Backscattering coefficients for all frequencies and polarizations increased until Day Of Year (DOY) 271 and then decreased until harvesting stage (DOY 294). Time serious of soil moisture content was not a corresponding with backscattering over the whole growth stage, although it increased relatively until early August (R2, DOY 224). We conducted the relationship between the backscattering coefficients of each band and soil moisture content. Backscattering coefficients for all frequencies were not correlated with soil moisture content when considered over the entire stage ($r{\leq}0.50$). However, we found that L-band HH polarization was correlated with soil moisture content (r=0.90) when Leaf Area Index (LAI)<2. Retrieval equations were developed for estimating soil moisture content using L-band HH polarization. Relation between L-HH and soil moisture shows exponential pattern and highly related with soil moisture content ($R^2=0.92$). Results from this study show that backscattering coefficients of radar scatterometer appear effective to estimate soil moisture content.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.3
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• pp.427-433
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• 2013

This study was designed to examine changes in the physicochemical properties of extruded corn fibers with different amounts of feed moisture (30, 40, and 50%). The screw speed and die temperature were fixed to 200 rpm and $140^{\circ}C$, respectively. The crude ash, fat, and protein in corn fiber decreased from the extrusion process. The insoluble dietary fiber in corn fibers decreased, while soluble dietary fiber increased at a feed moisture of 30%. The specific length of the extruded corn fiber increased while the specific mechanical energy input, density, breaking strength, and elastic modulus decreased. The water absorption index (WAI) and reducing sugar content of the corn fibers did not significantly change, but the water soluble index (WSI) decreased as the feed moisture content of the corn fiber increased. On the other hand, the WAI of de-starched corn fiber decreased while WSI and reducing sugars increased as the feed moisture content of the corn fiber increased.