• Bulletin of the Korean Chemical Society
• /
• v.21 no.11
• /
• pp.1101-1105
• /
• 2000

A simultaneous determination method of BTEX (benzene, toluene, ethylbenzene, o,m.p-xylene) and TPH (kerosene, diesel, jet fuel and bunker C) in soil with gas chromatography/flame ionization detection (GC-FID) was described. The effects of extracti on method, extraction solvent, solvent volume and extraction time on the extraction performance were studied. A sonication method was simpler and more efficient than Soxhlet or shaking methods. Sonication with 10 mL of acetone/methylene chloride (1 : 1, v/v) for 10 min was found to be optimal extraction conditions for 20 g of soil. Peak shapes and quantification of BTEX and TPH were excellent, with linear calibration curves over a wide range of 1-500 mg/L for BTEX and 10-5000 mg/L for TPH. Good reproducibilities by sonication were obtained, with the RSD values below 10%. By using about 20 g of soil, detection limits were 0.8 mg/L for BTEX and 10 mg/L for TPH. The advantages of this procedure are the use of simple and common equipment, reduced volumes of organic solvents, rapid extraction periods of less than 20 min, and simultaneous analysis of volatile and semivolatile compounds.

• Journal of the Korean Geotechnical Society
• /
• v.27 no.5
• /
• pp.85-92
• /
• 2011

The dynamic behavior of piles becomes very complex due to soil-pile dynamic interaction, soil non-linearity, resonance phenomena of soil-pile system and so on. Therefore, the proper numerical simulation of the pile behavior needs much effort and calculation time. In this research, a new modeling method, which can be applied to the conventional finite difference analysis program FLAC 3D, was developed to reduce the calculation time. The soil domain in this method is divided into a near-field region and a far-field region, which is not influenced by the soil-pile dynamic interaction. Then, the ground motion of the far-field is applied to the boundaries of the near-field instead of modeling the far-field region as finite meshes. In addition, the soil non-linearity behavior is modeled by using the hysteretic damping model, which determines the soil tangent modulus as a function of shear strain and the interface element was applied to simulate the separation and slip between the soil and pile. The proposed method reduced the calculation time by as much as one third compared with a usual modeling method and maintained the accuracy of the calculated results. The calculated results by the proposed method showed a good agreement with the prototype pile behavior, which was obtained by applying a similitude law to the 1-g shaking table test results.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.8 no.2
• /
• pp.83-88
• /
• 2003

A cellulose-producing strain isolated from rotten apples was identified as Gluconacetobacter hansenii based on its physiological properties and the 16S rDNA complete sequencing method, and specifically named Gluconacetobacter hansenii PJK. The amount of bacterial cellulose (BC) produced by G. hansenii PJK in a shaking incubator was 1.5 times higher than that produced in a static culture. The addition of ethanol to the medium during cultivation enhanced the productivity of bacterial cellulose, plus the supplementation of 1% ethanol into the culture medium made the produced BC aggregate into a big lump and thus protected the bacterial-cellulose-producing G. hansenii PJK cells in the shear stress field from being converted into non-cellulose-producing (Cel) mutants. Cells subcultured three times in a medium containing ethanol retained their ability to produce BC without any loss in the production yield.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2000.04a
• /
• pp.477-484
• /
• 2000

Earthquake response analyses are conducted for the investigation of the ground shaking during the 1995 Hyogoken-nambu earthquake. Port Island a man made island with about 8{{{{ KAPPA m^2 }} area is chosen for this purpose Because earthquake measurement with vertical array was conducted there. Strain dependent characteristics of soil can be modeled well into Hardin-Drnevich Model. Four analyses are conducted : total stress analysis by equivalent linear method non-linear method. and two effective stress analyses. All analyses except equivalent linear analysis show fairy good agreement with observed record mainly because the non-linear behavior of Holocene clay layer has predominant effect on the behavior of fill, However detailed investigation show that effective stress analyses give much better prediction than total stress analyses.

• Journal of the Ergonomics Society of Korea
• /
• v.19 no.1
• /
• pp.91-100
• /
• 2000

In this paper the intent recognition system which recognizes the human's head movements as a simple non-verbal intent representation is presented. The system recognizes five basic intent representations. i.e., strong/weak affirmation. strong/weak negation, and ambiguity by image processing of nodding or shaking movements of head. The vision system for tracking the head movements is composed of CCD camera, image processing board and personal computer. The modified template matching method which replaces the reference image with the searched target image in the previous step is used for the robust tracking of the head movements. For the improvement of the processing speed, the searching is performed in the pyramid representation of the original image. By inspecting the variance of the head movement trajectories. we can recognizes the two basic intent representations - affirmation and negation. Also, by focusing the speed of the head movements, we can see the possibility which recognizes the strength of the intent representation.

• Journal of Nutrition and Health
• /
• v.15 no.1
• /
• pp.9-14
• /
• 1982

The present paper describes a colorimetric method of determining the free and total unsaturated fatty acids in animal tissues. The procedure is based in three steps on the following principles : First step is that the tissue homogenates are extracted in chilled acetone in order to eliminate the interfering substance, such as phospholipids, sulfatides and proteins. At next step, after centrifugation acetone layer is decanted and evaporated to dryness. Then the extract is shaken with heptane to solve in the solvent. That the characteristic nature of copper salts of unsaturated fatty acids are freely soluble in heptane and those of saturated acids are not is the bases of separating one from another. Thus unsaturated fatty acids can be isolated in heptane as their salts from saturated acids and other lipid mixture by shaking with copper reagent. Finally the yellowish brown color developed by adding color reagent (0.2% sodium diethyldithiocarbamate in n-butanol solution) which reacts with the copper salts of the acids and produces the color is measured colorimetrically.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.35 no.3
• /
• pp.66-73
• /
• 2003

Alkaline cellulolytic enzymes are prepared from Coprinus cinereus 2249. Recovery method of enzyme protein from cultured medium and effect factors on enzyme activity of protein were investigated. The results could summarized as follows, \circled1 Amount of enzyme protein from cultured medium was highest in incubation with shaking and addition of skim milk. \circled2 Protein from cultured medium was alkaline enzymatic protein which shows the highest activity at pH 9.0. \circled3 The most effective recovery method of enzyme protein was the precipitation of protein by addition of cultured medium of protein in ethanol. \circled4 The enzyme activity was enhanced by tween-80 and decreased with $Al_2(SO_4)_3$, $H_2O_2$et al, and was little changed with metal ions except $Hg^{++}$.

• Bulletin of the Korean Chemical Society
• /
• v.29 no.10
• /
• pp.1932-1936
• /
• 2008

A new analytical method using 1-(2-pyridylazo)-2-naphthol modified $SiO_2$ nanoparticles as solid-phase extractant has been developed for the preconcentration of trace amounts of mercury(II) in different water samples. Conditions of the analysis such as preconcentration time, effect of pH, sample volumes, shaking time, elution conditions and effects of interfering ions for the recovery of analyte were investigated. The adsorption capacity of nanometer $SiO_2$-PAN was found to be 260 ${\mu}molg^{-1}$ at optimum pH and the detection limit (3$\sigma$) was 0.48 ${\mu}gL^{-1}$. The extractant showed rapid kinetic sorption. The adsorption equilibrium of mercury(II) on nanometer $SiO_2$-PAN was achieved just in 5 mins. Adsorbed mercury(II) was easily eluted with 5 mL of 6 M hydrochloric acid. The maximum preconcentration factor was 50. The method was applied for the determination of trace amounts of mercury(II) in various water samples and industrial effluents.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1992.04a
• /
• pp.95-101
• /
• 1992

The Pseudodynamic test is a new experimental technique for simulating the earthquake response of structures or structural components in the time domain. It is especially efficient for testing structures that are too large, heavy or strong to be tested on a shaking table. But the obtained responses in the Pseudodynamic test are distorted by the experimental errors inevitably during control and measurement procedures. The studies are to investigate the effects of the experimental errors on the Pseudodynamic responses and apply a correction method to the Pseudodynamic testing algorithm. It is shown that the corrected responses using the Equivalent Energy Compensation Method are in a good correlation with the theoretical ones. Thus, the corrected Pseudodynamic responses could be reliable for evaluating the seismic performance of structural systems.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 1996.10a
• /
• pp.202-209
• /
• 1996

In this paper, two dimensional vertical and comer infinite elements which can include multiple wave components to model underlying half space are developed. These elements are natural and economical to model underlying stiff half space or rock. To verify the behavior of these infinite elements, vertical, horizontal, and rocking compliances of a rigid strip foundation on a viscoelastic soil profile are analyzed and compared with those of Tzong and Penzien who used the boundary solution method. Good agreements are noticed between the two methods. The influence of material properties like Poisson's ratio, material damping, and stiffness ratio of layers as well as the influence of geometrical properties such as layer thicknesses and depth of foundation embedment are studied. Example analysis is carried out for the shaking table which is located in KIMM(Korea Institute of Machinery and Materials), and the vertical and horizontal displacements of the analysis are compared with the measured, and show good results and demonstrate the efficiency of the proposed method.