• Magazine of the Korean Society of Agricultural Engineers
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• v.17 no.3
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• pp.3815-3832
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• 1975

This study was made to investigate various engineering properties of earth materials resulting from their changes in density and moisture content. The results obtained in this study are summarized as follows: 1. The finner the grain size is, the bigger the Optimum Moisture Content(OMC) is, showing a linear relationship between percent passing of NO. 200 Sieve (n) and OMC(Wo) which can be represented by the equation Wo=0.186n+8.3 2. There is a linear relationship of inverse proportion between OMC and Maximum Dry Density (MDD) which can be represented by the equation ${\gamma}$d=2.167-0.026Wo 3. There is an exponential curve relationship between void ratio (es) and MDD whose equation can be expressed ${\gamma}$d=2.67e-0.4550.9), indicating that as MDD increases, void ratio decreases. 4. The coefficent of permeability increases in proportion to decrease of the MDD and this increase trend is more obvious in coarse material than in fine material, and more obvious in cohesionless soil than in cohesive soil. 5. Even in the same density, the coefficient of permeability is smaller in wet than in dry from the Optimum Moisture Content. 6. Showing that unconfined compressive strength increases in proportion to dry density increase, in unsaturated state the compacted in dry has bigger strength value than the compacted in wet. On the other hand, in saturated state, the compacted in dry has a trend to be smaller than the compacted in wet. 7. Even in the same density, unconfined compressive strength increases in proportion to cohesion, however, when in small density and in saturated state, this relationship are rejected. 8. In unsaturated state, cohesion force is bigger in dry than in wet from OMC. In saturated state, on the other hand, it is directly praportional to density. 9. Cohesion force decreases in proportion to compaction rate decrease. And this trend is more evident in coarse matorial than in fine material. 10. Internal friction angle of soil is not influenced evidently on the changes of moisture content and compaction rate in unsaturated state, On the other hand in saturated state it is influenced density. 11. Cohesion force is directly proportional to unconfined compressive strength(qu), indicating that it has approximately 35 percent of qu in unsaturated state and approximately 70 percent of qu in saturated state.

• Korean Journal of Environmental Agriculture
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• v.39 no.1
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• pp.44-49
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• 2020

BACKGROUND: Benzo(a)pyrene is a highly toxic substance which has been listed as a Group I carcinogen by the International Agency for Research on Cancer. There have been numerous studies by researchers worldwide on benzo(a)pyrene. Soxhlet, ultrasound-assisted, and liquid-liquid extractions have been widely used for the analysis of benzo(a)pyrene. However these extraction methods have significant drawbacks, such as long extraction time and large amount of solvent usage. To overcome these disadvantages, we aimed to establish a rapid residual analysis of benzo(a)pyrene content in agricultural products and soil samples. METHODS AND RESULTS: A Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method was used as the pretreatment procedure. For rapid residual analysis of benzo(a)pyrene, a modified QuEChERS method were used, and the best codition was demonstrated after various performing instrument analysis. The extraction efficiency of this method was also compared with Soxhlet extraction, the current benzo(a)pyrene extracting method. Although both methods showed high recovery rates, the rapid residual analysis method markedly reduced both the measurement time and solvent usage by approximately 97% and 96%, respectively. CONCLUSION: Based on these results, we suggest the rapid residual analysis method established through this study, faster and more efficient analysis of residual benzo(a)pyrene in major agricultural products such as rice, green and red chili peppers and also soil samples.

• Journal of the Korean GEO-environmental Society
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• v.22 no.9
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• pp.5-16
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• 2021

In this study, piezocone coefficients of clays (Hwasung, Gunsan, Changwon, Busan) were analyzed from piezocone penetration tests those accompanied with vane shear and UU tests. Piezocone coefficients of west sea clays (Hwasung, Gunsan), i.e, N_kt is 12.6 and N_qu is 8.8, while those of south sea clays are 16.5 and 9.2 respectively. The difference of liquid limit between south and west clays causes main roles those which west sea clay is generally lower than 50%, i.e, CL, and liquid limit of south sea clay is mostly higher than 50%, i.e CH. Piezocone coefficients obtained from several tests show similar trends even though they still have some differences depending on each test. However, they show clear differences depending on liquid limit. Therefore, piezocone coefficients need to be used with caution depending on LL.

• The Journal of Korean Obstetrics and Gynecology
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• v.27 no.1
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• pp.81-100
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• 2014

Objectives: The object of this study was to observe the in vitro anti-bacterial and anti-inflammatory effects of six single aqueous herbal extracts-Quisqualis Fructus (QuF), Meliae Cortex (MeC), Arecae Semen (ArS), Crassirhizomae Rhizoma (CrR), Ulmi Pasta Semen(UlS), Torreyae Semen(ToS)- against Staphylococcus aureus (S. aureus) and Lipopolysaccharide(LPS)-activated Raw 264.7 cells. Methods: Anti-bacterial activities against S. aureus of aqueous extracts of QuF, MeC, ArS, CrR, UlS and ToS were detected using standard agar microdilution methods. In addition, the effects on the cell viability, prostaglandin $E_2$ ($PGE_2$), nitric oxide (NO), tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), interleukin (IL)-$1{\beta}$ and IL-6 productions of LPS activated Raw 264.7 cells were detected. The anti-bacterial and anti-inflammatory effects were respectively compared with lincomycin and piroxicam. Results: Minimal Inhibition Concentration (MIC) of aqueous extracts of QuF, MeC, ArS, CrR, UlS and ToS against S. aureus was respectively detected $5.625{\pm}4.075$ (3.125~12.500), $0.332{\pm}0.273$ (0.098~0.782), $1.094{\pm}0.428$ (0.782~1.563), $2.969{\pm}2.096$ (0.782~6.250), $9.375{\pm}4.419$ (3.125~12.500)>25 mg/ml. MIC of lincomycin was detected as $0.469{\pm}0.297$ (0.195~0.782) ${\mu}g/ml$ at same conditions. In addition, $ED_{50}$ against LPS-induced cell viabilities and cytokine releases of QuF, MeC, ArS, CrR, UlS and ToS was as follows - Cell viability: 66.370, 2.908, 1.747, 259.553, 18.150 and 34.160 mg/ml; NO production: 389.486, 0.294, 0.138, 523.060, 45.363 and 49.327 mg/ml; $PGE_2$ production: 114.271, 0.223, 0.046, 243.078, 8.829 and 28.947 mg/ml; TNF-${\alpha}$ production: 406.288, 0.343, 0.123, 9404.227, 125.406 and 140.775 mg/ml; IL-$1{\beta}$ production: 117.178, 0.135, 0.019, 237.451, 7.923 and 19.418 mg/ml; IL-6 production: 31.261, 0.105, 0.055, 128.434, 2.290 and 3.745 mg/ml. ED50 of piroxicam against LPS-induced cell viabilities, NO, $PGE_2$, TNF-${\alpha}$, IL-$1{\beta}$ and IL-6 were detected as 35.179, 6.552, 1.162, 7.273, 7.101 and $5.044{\mu}g/ml$, respectively at same conditions. Conclusions: All six single aqueous herbal extracts showed anti-bacterial effects against S. aureus, in the order of MeC, ArS, CrR, QuF and UlS aqueous extracts except for ToS; they did not showed any anti-bacterial effects (MIC>25 mg/ml). They also showed anti-inflammatory effects against LPS-activated Raw 264.7 cells in the order of ArS, MeC, UlS, ToS, QuF and CrR aqueous extracts. It means that the ArS and MeC will be showed favorable potent anti-bacterial and related anti-inflammatory effects.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.1
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• pp.9-18
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• 2010

There are two kinds of models in two-phase pressured drop; homogeneous flow model and separated flow model. Many previous researchers have developed correlations for two-phase pressure drop in a microchannel. Most correlations were modified Lockhart and Martinelli's correlation, which was based on the separated flow model. In this study, experiments for adiabatic liquid water and nitrogen gas flow in rectangular microchannels were conducted to investigate two-phase pressure drop in the rectangular microchannels. Two-phase frictional pressure drop in the rectangular microchannels is highly related with flow regime. Homogeneous model with six two-phase viscosity models: $Owen^{(21)}$'s, $MacAdams^{(22)}$'s, Cicchitti et ${al.}^{(23)}$'s, Dukler et ${al.}^{(24)}$'s, Beattie and ${Whalley}^{(25)}$'s, Lin et ${al.}^{(26)}$'s models and six separated flow models: Lockhart and $Martinelli^{(27)}$'s, ${Chisholm}^{(31)}$'s, Zhang et ${al.,}^{(15)}$'s, Lee and ${Lee}^{(5)}$'s, Moriyama and ${Inue}^{(4)}$'s, Qu and $Mudawar^{(8)}$'s models were assessed with our experimental data. The best two-phase viscosity model is Beattie and Whalley's model. The best separated flow model is Qu and Mudawar's correlation. Flow regime dependency in both homogeneous and separated flow models was observed. Therefore, new flow pattern based correlations for both homogeneous and separated flow models were individually proposed.

• Korean Journal of Veterinary Service
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• v.42 no.4
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• pp.289-296
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• 2019

A novel rapid procedure with liquid chromatography tandem mass spectrometry (LC-MS/MS) detection has been developed by changing various conditions including sample preparation such as QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) methodology. This work has been involved the optimization and validation of detection method for fluoroquinolones which are widespread used in livestock especially in the chicken. Five grams of homogenized chicken muscle were extracted with QuEChERS EN and acetonitrile containing 5% formic acid and cleaned with anhydrous magnesium sulfate and C₁₈ sorbent. The separation was performed on Acquity UPLC HSS T3 (2.1 mm×100 mm, 1.8 ㎛) column. The mobile phase A and B were composed of water containing 0.1% formic acid and acetonitrile containing 0.1% formic acid, respectively. Flow rate was 0.25 mL/min and column temperate was 40℃. LC-MS/MS with multiple reaction monitoring has been optimized for ten fluoroquinolones (ciprofloxacin, danofloxacin, difloxacin, enrofloxacin, marbofloxacin, norfloxacin, ofloxacin, orbifloxacin, pefloxacin and sarafloxacin). The method developed in this study has been presented good linearity with correlation coefficient (R²) of 0.9971~0.9998. LOD and LOQ values ranged from 0.09 to 0.76 ppb and from 0.26 to 2.29 ppb, respectively. The average recoveries were from 77.46 to 111.83% at spiked levels of 10.0 and 20.0 ㎍/kg. Relative standard deviation (%) ranged 1.28~11.90% on intra-day and 3.10~8.38 % on inter-day, respectively. This analysis method was applicable to the livestock residue laboratories and was expected to be satisfactory for the residue surveillance system.

• Applied Chemistry for Engineering
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• v.25 no.2
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• pp.142-146
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• 2014

The separation of nitrogen heterocyclic compound (NHC) contained in a model coal tar fraction of nine components system was investigated by distribution equilibrium. The model coal tar fraction comprising NHC group (NHCs; indole (In), quinoline (Q), iso-quinoline (iQ), quinaldine(Qu)), bicyclic aromatic compound group (BACs; 1-methylnaphthalene (1MN), 2-methylnaphthalene (2MN), dimethylnaphthalene (DMN)), biphenyl (Bp) and phenyl ether (Pe) and the aqueous methanol were used as the raw materials and the solvent of this work, respectively. A batch-stirred tank was used as the liquid-liquid contact unit of this work. The distribution coefficient of NHCs increased by increasing the equilibrium operation temperature, whereas the selectivity of NHCs with respect to BACs decreased. Decreasing the initial volume ratio of water to the solvent resulted in deteriorating the selectivity of NHCs in reference to BACs, but improving the distribution coefficients of NHCs. At a fixed experimental condition, the sequence of the distribution coefficient and the selectivity with reference to BACs for each groups was increased in order of NHCs > Bp > BACs > Pe and NHCs > Bp> Pe, respectively. Also, the sequence of the distribution coefficient for entire compounds was in order of In > iQ = Q > Qu > Bp > 1MN = 2MN > Pe > DMN. The maximum yield of NHCs and the selectivity of NHCs based on BACs obtained by methanol extraction were 94 and 23%, respectively. Furthermore, the recovery process for NHCs from coal tar was studied by using the experimental results from this work.

• Journal of Korean Philosophical Society
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• v.105
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• pp.423-460
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• 2008

Les positions qu'essait d'expliquer les $probl{\grave{e}}mes$ divers ${\grave{a}}$ propos de la $sexualit{\acute{e}}$, faisaient ressortir les points biologiques des actions $d^{\prime}{\hat{e}}tre$ humain par ${\acute{e}}volutionnisme$ plutot qu'explique les $probl{\grave{e}}mes$ de la nature humaine, $d{\acute{e}}sirs$ sexuelles, par les $sci{\acute{e}}t{\grave{e}}s$, les cultures et les'institutions. En face des questions des $possibilit{\acute{e}}s$ d'explications biologiques sur toutes les actions sexuelles, ils sont $plac{\acute{e}}s$ en crise. Le fait que $l^{\prime}{\hat{e}}tre$ humain est un'etre historique, n'implique pas ce qu'il est evolutionnaire. Pour cette raison, c'est difficile qu'on accepte le determisme biologique, $l^{\prime}{\acute{e}}volutionnisme$, sans conditions. En opposition avec cettes $id{\acute{e}}es$, Michel Foucault voudrait insister sur le fait de penser au sexe comme les $r{\acute{e}}sultats$ des productions sociologiques, politiques. Selon Foucault, la $sexualit{\acute{e}}$ n'est pas $donn{\acute{e}}$ de la nature que le pouvoir essaierait de mater, ou un domaine obscure que le savoir tendrait de $d{\acute{e}}voiler$, mais une sorte de dispositif historique. Donc, dans cet article, j'essaie d'examiner les processus, les differences, et les $probl{\grave{e}}mes$ entre les deux positions, puis je considere les limites philosophiques, des deux argumentations, et ses implications philosophique. Cela permet d'approcher ${\grave{a}}$ l'horizon divers du discours sexuelles de la $compr{\acute{e}}hension$.

• Applied Chemistry for Engineering
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• v.33 no.5
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• pp.477-481
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• 2022

As a part of improving the quality of crude methylnaphthalene (CMNO), this study was experimentally examined the reduction of nitrogen-containing compounds (NC) present in the CMNO by solvent extraction. The CMNO was composed of three kinds of NC [quinolone (QU), iso-quinoline (IQU), indole (IN)], three kinds of bicyclic aromatic compound [BAC; naphthalene (NA), 1-methylnaphthalene (1MNA), 2-methylnaphthalene (2MNA)] and biphenyl (BP) etc., in addition to an aqueous formamide solution, which were used as raw materials and a solvent, respectively. The increase in the volume fraction of water to the solvent in the initial state (y_w,0) caused a sharp decrease in the distribution coefficient and the yield of NC, but conversely raised the increased selectivity of NC based on 2MNA. The compositions of QU, IQU and IN in the raffinate oil recovered through the equilibrium extraction of batch co-current 5-stage under constant conditions [y_w,0 = 0.1, volume fraction of solvent to feed (CMNO) at the initial state = 1, operating temperature = 303 K, liquid-liquid contacting time = 72 h] were reduced by about 51.5%, 55.2%, and 71.8%, respectively, when compared to those of CMNO. From the excellent reduction rate of NC, the formamide extraction method suggested in this study can be expected to be a useful reduction method for NC contained in the CMNO.

• Applied Chemistry for Engineering
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• v.33 no.4
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• pp.431-435
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• 2022

The reduction of nitrogen-containing compounds (NC) containing the model crude methylnaphthalene oil (CMNO) of 5 compounds system was experimentally studied by solvent extraction. The model CMNO consisting of 3 kinds of NC including quinolone (QU), iso-quinoline (IQU), indole(IN) and 2 kinds of bicyclic aromatic compounds such as 1-methylnaphthalene (1MNA), 2-methylnaphthalene (2MNA) as raw materials, as well as the aqueous solution of formamide as a solvent, were used. The increase in the volume fraction of water to the solvent at the initial state (y_w,0) sharply decreased, but the distribution coefficient and the yield of NC conversely increased the selectivity of NC based on 2MNA, and an increase in the volume fraction of solvent to feed (S/F) simultaneously increased the distribution coefficient, yield and selectivity of NC. The yields of QU, IQU and IN under constant conditions (y_w,0 = 0.1, S/F = 1, equilibrium temperature 303 K) were 30%, 31% and 10%, respectively, and selectivity was 15, 15 and 20, respectively. From the excellent yield and selectivity of NC, the formamide extraction method of this study was expected as a method for reducing the NC contained in the model CMNO.