• Structural Engineering and Mechanics
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• v.61 no.5
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• pp.657-661
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• 2017

In this paper, it has been tried to propose a new semi analytical approach for solving nonlinear vibration of conservative systems. Hamiltonian approach is presented and applied to high nonlinear vibration systems. Hamiltonian approach leads us to high accurate solution using only one iteration. The method doesn't need any small perturbation and sufficiently accurate to both linear and nonlinear problems in engineering. The results are compared with numerical solution using Runge-Kutta-algorithm. The procedure of numerical solution are presented in detail. Hamiltonian approach could be simply apply to other powerfully non-natural oscillations and it could be found widely feasible in engineering and science.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1988.10a
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• pp.18-23
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• 1988

This study on the elasto-plastic analysis of spherical shell by rigia element method is classified into two parts : (1) theoretical consideration on elasto-plastic analysis of spherical shell, (2) elastic and elasto-plastic analysis of spherical shell with the open stiff ring. In 1982, Y. Tsuboi proposed the new analytical method which is called the rigid element method, for analyzing the elasto-plastic behavior of wall-type precast concrete structures by applying the concepts of rigid bodies-sprins model (i．e., when structures reach their ultimate state of leading, they may be yield, collapsed ana crushed into pieces, and each part or piece of structures mar move like a rigid body.). In this paper, for improvement and expansion this rigid element method, it is proposed the adaptation equation of rectangular-shaped spherical element and rectangular-shaped spherical bending element developed by present authors, and the analytical procedure for the elastic and the elasto-plastic increment method of structures.

• Journal of the Korean Society of Clothing and Textiles
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• v.27 no.11
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• pp.1350-1357
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• 2003

This research was aimed to establish the standard extraction and analytical procedures for examining the chromophoric substance in madder root with the ultimate goal of identifying the dyes in badly faded textiles of archaeological origin. The separation temperature of gas chromatography, pH and other extraction conditions were tested. The results were as follows: The suitable separation temperature for the GC cappillary column was 50∼305$^{\circ}C$, and methanol was a good GC solvent for both standard alizarin and madder extraction. The best extraction of madder was achieved by 90 min soaking in room temperature followed by filtration and the actual heat extraction procedure. The best pH for extracting alizarin was pH 3 and above pH 5 alizarin was not detectible. Only alizarin and no purpurin was found in the extraction of the currently used madder plant.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.11a
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• pp.135-138
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• 2003

Based on solid phase extraction, gas chromatography and mass spectrometry procedure for determining phenol and its derivatives in natural water was presented. In solid phase extraction, three types of techniques using solid phase adsorption material were treated with acid and salt, and converted second portion of acetyl derivatives. Under the these condition, extraction efficiency and detection ability dependent on extraction methods were discussed. Obtained results using optimized solid phase extraction techniques showed more convenience, simplifier and lower cost than the conventional analytical methods with holding wide dynamic range and lower detection limits.

• Journal of Korean Society for Atmospheric Environment
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• v.26 no.4
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• pp.449-452
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• 2010

In this article, the performance of the THC analyzer was inspected using two different span gases of methane ($CH_4$) and propane ($C_3H_8$). To explore the effect of standard gas selection, MicroFID system was tested by the following procedures. Initially, the system is spanned by propane gas of 60 ppm (or 180 ppmC). The system is then run against methane standards prepared at 5 different concentrations of 200, 250, 300, 400, and 500 ppm. According to the suggestion of the KMOE's test procedure to use multiplying a factor of 3 (for propane), the resulting THC values derived by methane standards were systematically biased with ~500% error relative to true value. This paper discusses the interpretation procedures to obtain the least biased THC values for a given span set-up.

• Water for future
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• v.12 no.2
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• pp.56-62
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• 1979

Many methods of estimating design floods from rainfall data involve a trial and error procedure to determine the duration of the design rainfall, which is very complicated and time-consuming. In this study, an effort was given to derive an analytical expression for estimating the appropriate duration for use with a particular unit hydrograph. According to the so-derived analytical expression the coordinateds of hvdrograph curve and rainfall curve for the Musim Representative Basin were computed and then plotted on a same scal graph paper on which the critical durations of design rainfall excess of various recurrence intervals were determined by the point of intersection of the tow curves.

• Journal of Food Hygiene and Safety
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• v.9 no.2
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• pp.89-94
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• 1994

A simple, safe, and sensitive gas chromatographic method using packed column and electron capture detector to analyze 2, 4-D herbicide in imported lemon, grapefruit, and orange was described and its usefulness evaluated. In this scheme of analysis the acid herbicide was converted into its alkyl esters by an one-step reaction prior to analysis. The herbicide in the fruits was extracted with ethyl acetate and partitioned against dichloromethane for purification, and the extracts finished partitioning were derivatized with alcohol, using sulfuric acid as a catalyst to form the corresponding alkyl derivatives. The analytical scheme studiedwas found to be applicable for the herbicide in the fruits without a column clean-up procedure. The mean recoveries of the herbicide for lemon samples fortified at 0.1 mg/kg and 1.0 mg/kg were 93% and 95%, respectively. The detection limit was 0.5 $\mu\textrm{g}$/kg for 2.4-D methyl ester.

• Analytical Science and Technology
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• v.23 no.6
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• pp.615-618
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• 2010

An oxygen bomb combustion procedure were studied for determination of heavy metal in polymer materials such as polyvinyl chloride and polypropylene by ICP-AES. This method is proposed as a rapid and simple sample preparation for decomposition of polymer containing certified contents of the analytes by teflon coated oxygen bomb combustion using different absorbing solution. The recoveries of metal were found to be 30~102% from absorbed solution by ICP-AES method using polypropylene certified reference material(PP CRM-As, Ba, Cd, Hg, Pb, Zn). The recoveries of metal using PVC CRM(Cd, Hg, Pb) was found to be 45 ~101% with same procedures.

• Journal of the Korea institute for structural maintenance and inspection
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• v.7 no.1
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• pp.131-138
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• 2003

This paper presents an analytical prediction of the prestress losses of prestressed concrete bridges. In this study a numerical procedure and computer program is developed to analyze the behavior of prestressed concrete bridges considering the time-dependent properties of material. It accounts for the aging, creep and shrinkage of concrete and the stress relaxation of prestressed steel. The structural model uses two dimensional plane frame elements with three nodal degree of freedom and is analyzed based on the finite element method. Member cross section can consist of concrete, reinforcement and prestressing steel. Two different set of equations for the prediction of time-dependent material properties of concrete are presented, which are ACI, CEB-FIP. The proposed numerical method for the prestress losses of prestressed concrete bridges is verified by comparison with reliable experimental results.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.500-509
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• 2015

This paper presents the single objective design optimization of plate-fin heat sink equipped with fan cooling system using Genetic Algorithm. The proper heat sink and fan model are selected based on the previous studies. And the thermal resistance of heat sinks and fan efficiency during operation are calculated according to specific design parameters. The objective function is combination of thermal resistance and fan efficiency which have been taken to measure the performance of the heat sink. And Decision making procedure is suggested considering life time of semiconductor and Fan Operating cost. And also Analytical Model used for optimization is validated by Fluent, Ansys 13.0 and this model give a quite reasonable and reliable design.