• Korean Chemical Engineering Research
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• v.43 no.4
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• pp.458-466
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• 2005

Full-scale utilizations of batch separation process often require knowledge about thermodynamics and correlation techniques of physical properties of complex mixture consisting of a great number of many unknown components. Various empirical correlations have been proposed to predict the physical properties mostly about the pseudocomponent of petroleum. In this study, one parameter correlations are developed for the calculations of the critical physical properties and ideal heat capacity of the pseudo-component of coal tar fractions. Developed model can provide a tool for the design and operations for the batch distillation of coal tar mixture.

• Macromolecular Research
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• v.14 no.4
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• pp.456-460
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• 2006

The electrical, morphological, and mechanical properties of poly carbonate (PC)/multi-walled carbon nan-otube (MWNT) composites were studied by electrical conductivity, electromagnetic interference shielding efficiency (EMI SE), scanning electron microscopy, and tensile strength measurements. In the electrical property analysis of the PC/MWNT composites, the percolation threshold of the PC/MWNT composites was observed between 1.5 and 2.5 wt% MWNT content. From the electrical conductivity and EMI SE studies, the theoretical values of the EMI SE were in good agreement with the experimental values of the EMI SE. From the morphology of the PC/MWNT composites, it was observed that MWNT is dispersed homogenously in the PC matrix. From the electrical conductivity and morphological studies, it was suggested that the percolation threshold of the PC/MWNT composites is related with the morphological results in that MWNT is apparently interconnected to form an electrical pathway. The mechanical properties of the PC/MWNT composites peaked at the MWNT content of 2.5 wt%.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.1
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• pp.56-64
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• 2017

Soil quality has been regarded as an important factor for maintaining sustainability of ecosystem. Main purpose of this research was i) to select minimum factor for predicting biomass, and ii) to calculate soil quality index for biomass according to soil chemical properties. Result showed that soil pH, electrical conductivity (EC), soil organic matter (SOM), cation exchange capacity (CEC), and available phosphorus are minimum data set for calculating biomass production in soil. Selected representative soil chemical properties were evaluated for soil quality index and rated from 1 to 5 (1 is the best for biomass production). Percentage of each grade in terms of biomass production in national wide was 14.52, 35.23, 33.03, 6.47, 10.75% respectively. Although, only soil chemical properties were evaluated for calculating optimum soil quality, result of this research can be useful to understand basic protocol of soil quality assessment in national wide.

• Journal of Soil and Groundwater Environment
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• v.24 no.2
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• pp.8-22
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• 2019

Among numerous chemicals used globally, the number of emerging contaminants is increasing. Numerical modeling for contaminant fate and transport in the subsurface is critical to evaluate environmental and health risk. In general, such models require physicochemical properties of contaminants as input values, which can be found in numerous chemical databases (DB). However, there exist lack of information specific to recently emerging contaminants, which requires estimation of physicochemical properties using regression programs. The purpose of the study is to introduce the workflow for identifying physicochemical properties of potential contaminants utilizing numerous chemical DBs, which frequently lists up potential contaminants for estimating chemical behavior. In this review paper, details of several chemical DBs such as KISChem, TOXNET, etc. and regression programs including EPI $Suite^{TM}$, ChemAxon, etc. were summarized and also benefit of using such DBs were explained. Finally, a few examples were introduced to estimate predominant phase, removal ratio, partitioning, and eco-toxicities by searching or regressing physicochemical properties.

• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1237-1240
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• 2010

The mechanical properties of multiwalled carbon nanotubes (MWNTs)-reinforced epoxy matrix composites with different weight percentages of MWNTs have been investigated. Also, the morphologies and failure behaviors of the composites after mechanical tests are studied by SEM and TEM analyses. As a result, the addition of MWNTs into the epoxy matrix has a remarkable effect on the mechanical properties. And the fracture surfaces of MWNTs/epoxy composites after flexural strength tests show different failure mechanisms for the composites under different nanotube contents. Also, a chemical functionalization of MWNTs can be a useful tool to improve the dispersion of the nanotubes in an epoxy system, resulting in increasing the mechanical properties of the composite materials studied.

• Journal of Biosystems Engineering
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• v.24 no.5
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• pp.407-414
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• 1999

To evaluate the quality of flame-peeled chestnuts, their physical and chemical properties were analyzed. The physicochemical properties of flame-peeled chestnuts, including geometrical shape, texture and chemical composition, were compared to those of hand-peeled ones. For the flame-peeled chestnuts, some properties in heated and non-heated sections were separately analyzed. The color, texture such as springness, cohesiveness, adhesiveness, hardness and chewiness, moisture content, and reducing sugar of the heated section of the flame-peeled chestnuts were significantly different with their non-heated section. But the physicochemical properties of the non-heated section of the flame-peeled chestnuts were similar to those of the hand-peeled ones.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.2
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• pp.209-214
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• 2012

This experiment was carried out to investigate the replaceability of chemical fertilizer by SCB liquid fertilizer (SCB) in pear orchard for 5 years. The effects on the mineral content of leaf, fruit quality, yield and soil chemical properties are as follows: The mineral content of leaf showed no difference between the treatments; two SCB liquid fertilizer treatments based on the N (SCB-N) and K (SCB-K) content, and control (chemical fertilizer application). There were no significant differences in yield, titratable acidity and weight of the fruit although the figure of fruit weight was high in SCB-N treatment. Soluble solids content was higher in the SCB treatments than the control. Soil chemical properties such as the content of soil organic matter, available soil phosphate and exchangeable cation were not different, although soil pH was higher in SCB treatments. In conclusion, it is suggest that the use of chemical fertilizer in pear orchard could be replaced by the application of SCB liquid fertilizer because of the same effect on the growth of pear tree and soil chemical properties.

• Fashion & Textile Research Journal
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• v.15 no.3
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• pp.430-436
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• 2013

The purpose of this study investigates the effects of electron beam(EB) irradiation on the chemical and morphological properties of Hansan ramie fiber. Hansan ramie fibers were irradiated with electron beam doses of 0, 1, 3, 5 and 10kGy. The effect of electron beam irradiation on the chemical components of fibers as well as the surface chemical and morphological properties were investigated using chemical component analysis methods based on TAPPI standards, XPS, and SEM. The results indicate that the surface layers can be removed under suitable EB irradiation doses. Alcohol-benzene extraction and lignin content increases gradually with an increase in EB irradiation and reaching a maximum at an EB dose of 3kGy, and decreases at 10kGy. The surface chemical changes measured by XPS corresponded to the chemical composition analysis results. The C1 peak and the O/C ratio decreased with the removal of the multi-layer and primary layer by EB irradiation. The SEM images show the inter-fibrillar structure etched by EB irradiation up to 5kGy. At 10kGy, the surface structure of the ramie fiber shows highly aligned and distinctive striations in a longitudinal direction. The removal of these exterior layers of the fiber was confirmed by changes in surface morphology as observed in SEM images.

• Proceedings of the Korean Geotechical Society Conference
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• 1999.11c
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• pp.39-55
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• 1999

Geotextile composites to improve the weather ability were composed of recycled polyester geotextile with carbon black as ultraviolet stabilizer and polypropylene geotextile by needle-punching method, and evaluated physical properties, ultraviolet resistance and chemical stability. Retention ratio of tensile properties of non woven polypropylene geotextiles were decreased about 50% by the exposed condition with ultraviolet but those of geotextile composites were slightly decreased than polypropylene geotextiles. Geotextile composites which have larger weights of polyester geotextile were more stable against ultraviolet. For chemical stability, the changes of tensile properties of geotextile composites were in the range of -20~＋10% at the various chemical conditions.

• Journal of Ecology and Environment
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• v.30 no.1
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• pp.39-47
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• 2007

The relationships between the cover of herbaceous species and 15 soil chemical properties (organic carbon contents, total N, available P, exchangeable K, Na, Ca and Mg, HCl-extractable Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn) in nine poorly controlled waste landfill sites in Korea were examined by correlation analysis and multiple regression equations. Species showed different patterns of correlation between their cover values and soil chemical properties. The cover of Ambrosia artemisiifolia var. elatior, Aster subulatus var. sandwicensis and Erechtites hieracifolia were negatively correlated with the contents of Fe, Mn and Ni within landfill soils. Total cover of all species in quadrats was positively correlated with the contents of Cd and negatively correlated with the contents of Mn and Fe from stepwise regression analysis with 15 soil properties. Canonical correspondence analysis demonstrated that the distribution of native and exotic plants on poorly controlled landfills was significantly influenced by the contents of Na and Ca in soils, respectively.