• Title/Summary/Keyword: 3-D Analytical Method

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A three-dimensional numerical model for shallow water flows using a free surface correction method (자유수면 보정기법을 이용한 3차원 천수유동 수치모형)

  • Jang, Won-Jae;Lee, Seung-Oh;Cho, Yong-Sik
    • 한국방재학회:학술대회논문집
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    • 2007.02a
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    • pp.181-185
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    • 2007
  • A free-surface correction(FSC) method is presented to solve the 3-D shallow water equations. Using the mode splitting process, FSC method can simulate shallow water flows under the hydrostatic assumption. For the hydrostatic pressure calculation, the momentum equations are firstly discretized using a semi-implicit scheme over the vertical direction leading to the tri-diagonal matrix systems. A semi-implicit scheme has been adopted to reduce the numerical instability caused by relatively small vertical length scale compare to horizontal one. and, as the free surface correction step the final horizontal velocity fields are corrected after the final surface elevations are obtained. Finally, the vertical final velocity fields can be calculated from the continuity equation. The numerical model is applied to the calculation of the simulation of flow fields in a rectangular open channel with the tidal influence. The comparisons with the analytical solutions show overall good agreements between the numerical results and analytical solutions.

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Characteristic Analysis of a Linear Induction Motor for a Lightweight Train According to Various Secondary Schemes

  • Lee, Hyung-Woo;Lee, Sung-Gu;Park, Chan-Bae;Lee, Ju;Park, Hyun-June
    • International Journal of Railway
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    • v.1 no.1
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    • pp.6-11
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    • 2008
  • This paper presents a performance characteristic analysis methodology for a linear induction motor used for a lightweight train. In general, an analytical method cannot provide accurate results in a linear motor because of large airgap, end effect, transverse edge effect, 3-dimensional configurations, large leakage, and so on. Besides, a numerical method requires lots of memory and solving time for transient analysis. However, the suggested methodology which is a kind of hybrid solution with an analytical method and a numerical method is very fast and accurate. Based on the methodology, 3-D FEM analyses for various design schemes of the secondary reaction plate have been done and from the analysis results, the best configuration for an urban railway transit is chosen.

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Vibration analysis of a Timoshenko beam carrying 3D tip mass by using differential transform method

  • Kati, Hilal Doganay;Gokdag, Hakan
    • Structural Engineering and Mechanics
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    • v.65 no.4
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    • pp.381-388
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    • 2018
  • Dynamic behaviour of beam carrying masses has attracted attention of many researchers and engineers. Many studies on the analytical solution of beam with concentric tip mass have been published. However, there are limited works on vibration analysis of beam with an eccentric three dimensional object. In this case, bending and torsional deformations of beam are coupled due to the boundary conditions. Analytical solution of equations of motion of the system is complicated and lengthy. Therefore, in this study, Differential Transform Method (DTM) is applied to solve the relevant equations. First, the Timoshenko beam with 3D tip attachment whose centre of gravity is not coincident with beam end point is considered. The beam is assumed to undergo bending in two orthogonal planes and torsional deformation about beam axis. Using Hamilton's principle the equations of motion of the system along with the possible boundary conditions are derived. Later DTM is applied to obtain natural frequencies and mode shapes of the system. According to the relevant literature DTM has not been applied to such a system so far. Moreover, the problem is modelled by Ansys, the well-known finite element method, and impact test is applied to extract experimental modal data. Comparing DTM results with finite element and experimental results it is concluded that the proposed approach produces accurate results.

Analytical solutions for sandwich plates considering permeation effect by 3-D elasticity theory

  • Huo, Ruili;Liu, Weiqing;Wu, Peng;Zhou, Ding
    • Steel and Composite Structures
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    • v.25 no.2
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    • pp.127-139
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    • 2017
  • In this paper, an exact analytical solution for simply supported sandwich plate which considers the permeation effect of adhesives is presented. The permeation layer is described as functionally graded material (FGM), the elastic modulus of which is assumed to be graded along the thickness following the exponential law. Based on the exact three-dimensional (3-D) elasticity theory, the solution of stresses and displacements for each layer is derived. By means of the recursive matrix method, the solution can be efficiently obtained for plates with many layers. The present solution obtained can be used as a benchmark to access other simplified solutions. The comparison study indicates that the finite element (FE) solution is close to the present one when the FGM layer in the FE model is divided into a series of homogeneous layers. However, the present method is more efficient than the FE method, with which the mesh division and computation are time-consuming. Moreover, the solution based on Kirchhoff-Love plate theory is greatly different from the present solution for thick plates. The influence of the thickness of the permeation layer on the stress and displacement fields of the sandwich plate is discussed in detail. It is indicated that the permeation layer can effectively relieve the discontinuity stress at the interface.

Determination of methamphetamine and amphetamine enantiomers in human urine by chiral stationary phase liquid chromatography-tandem mass spectrometry

  • Sim, Yeong Eun;Ko, Beom Jun;Kim, Jin Young
    • Analytical Science and Technology
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    • v.32 no.5
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    • pp.163-172
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    • 2019
  • Methamphetamine (MA) is currently the most abused illicit drug in Korea and its major metabolite is amphetamine (AP). As MA exist as two enantiomers with the different pharmacological properties, it is necessary to determine their respective amounts in a sample. Thus a chiral stationary phase liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for identification and quantification of d-MA, l-MA, d-AP, and l-AP in human urine. Urine sample ($200{\mu}L$) was diluted with pure water and purified using solid-phase extraction (SPE) cartridge. A $5-{\mu}L$ aliquot of SPE treated sample solution was injected into LC-MS/MS system. Chiral separation was carried out on the Astec Chirobiotic V2 column with an isocratic elution for each enantiomer. Identification and quantification of enantiomeric MA and AP was performed using multiple reaction monitoring (MRM) detection mode. Linear regression with a $1/x^2$ as the weighting factor was applied to generate a calibration curve. The linear ranges were 25-1000 ng/mL for all compounds. The intra- and inter-day precisions were within 3.6 %, while the intra- and inter-day accuracies ranged from -5.4 % to 11.8 %. The limits of detection were 2.5 ng/mL (d-MA), 3.5 ng/mL (l-MA), 7.5 ng/mL (d-AP), and 7.5 ng/mL (l-AP). Method validation parameters such as selectivity, matrix effect, and stability were evaluated and met acceptance criteria. The applicability of the method was tested by the analysis of genuine forensic urine samples from drug abusers. d-MA is the most common compound found in urine and mainly used by abusers.

Magnetic Characteristic Analysis of Axial Flux Permanent Magnet Coupling based on Analytical method according to overload (해석적 방법을 이용한 축 방향 자속 영구자석 커플링의 과부하 자계특성해석)

  • Jang, Gang-Hyeon;Koo, Min-Mo;Choi, Jang-Young
    • Proceedings of the KIEE Conference
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    • 2015.07a
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    • pp.744-745
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    • 2015
  • This paper deals with magnetic characteristic analysis of axial flux permanent magnet coupling according to overload using analytical method. When magnet coupling has a slip, the eddy current induced in PM with conductivity. This eddy current make a distorted flux density. In this paper, we analyze the distorted flux density. The analytical results are validated extensively by comparing with 3d finite element analysis.

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Extraction of Water-Soluble Porphyrin and Metalloporphyrins into Acetonitrile by Salting-out

  • Tabata, Masaaki;Kumamoto, Midori
    • Analytical Science and Technology
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    • v.8 no.4
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    • pp.511-517
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    • 1995
  • A cationic water soluble porphyrin (5,10,15,20-tetrakis (l-methyl-pyridinium-4-yl)porphyrin, $H_2tmpyp^{4+}$) and its metalloporphyrins (MP) were easily extracted into acetonitrile separated by addition of sodium chloride ($4mol\;dm^{-3}$) in the presence of sodium perchlorate, where M denotes $Zn^{2+}$, $Cu^{2+}$, $Co^{3+}$, $Fe^{3+}$, and $Mn^{3+}$ and $P^{2-}$ is porphyrinate ion. The extracted ion-pair complexes were completely dissociated to $[MP(ClO_4)_3]^+$, and $[MP(ClO_4)_2]^{2+}$. The extraction and the dissociation constants were determined by taking into account of the partition constant of sodium perchlorate ($K_D=1.82{\pm}0.01$). The chemical properties of the separated acetonitrile phase as $E_{T(30)}$ and $D_{II,I}$ were determined and compared with other water miscible solvents (acetone, actonitrile, 1,4-dioxane, tetrahydrofuran, 1-propanol and 2-propanol). Furthermore, a sensitive and selective method was proposed for the determination of a subnanogram amount of copper(II) in natural water samples by using the present salting-out method and the porphyrins.

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Relationship-type R&D Portfolio Method for Selection of Core Technology (중점기술 선정을 위한 관계분석형 R&D 포트폴리오 방법)

  • Gam, Hyemi;Seo, Min Woo;Kim, Chansoo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.6
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    • pp.677-682
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    • 2018
  • The relationship-type research and development (R&D) portfolio is a method for selecting core technologies based on their unique purposes and characteristics when the criteria for selecting them are independent. This study presents a relationship-type R&D portfolio method as a way to derive core technologies, and describes the methodology by dividing it into three steps: 1) analyze the relationships between selection criteria and analytical indicators, 2) form a portfolio matrix that best matches each selection criteria, and 3) derive the core technologies. In this study, the relationships between four selection criteria for selecting core technologies and the analytical indicators for identifying the technology level, economics, and the technology itself, are written in a table with HoQ. Based on the relationship table, analytical indicators to be considered were derived to satisfy each selection criterion, and the derived analytical indicators and the selected technologies were constructed with two axes in the portfolio matrix. The satisfied portfolio, P0, that satisfies all four criteria, and the portfolio, P1~P4, that satisfies selection criteria based on the unique characteristics of the four criteria, were constructed, and core technologies derived. The selected core technologies can be utilized in selecting a core area against the future security environment through a process like key word analysis based on the specifications.

Development and Validation of an LC-MS/MS Method for Determination of Damaurone D in Rat Plasma and its Application to Pharmacokinetic Study in Rats

  • Lee, Wonpyo;Song, Im-Sook;Han, Young Taek;Choi, Min-Koo
    • Mass Spectrometry Letters
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    • v.10 no.1
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    • pp.38-42
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    • 2019
  • Damaurone D belongs to the genus Rosa and is a traditional medicinal product used for the treatment of depression, inflammation, and infectious diseases. The purpose of this study was to develop a simple liquid chromatography-tandem mass spectrometry method for the detection of damaurone D in rat plasma and to demonstrate its application in pharmacokinetic studies. Damaurone D and berberine (internal standard) were extracted with acetonitrile using a protein precipitation method. Mass transition was monitored in multiple reaction monitoring mode at m/z $323.2{\rightarrow}267.0$ for damaurone D and m/z $336.1{\rightarrow}320.0$ for berberine in positive ion mode. Analytical validation was conducted by evaluating the specificity, linearity, accuracy, precision, matrix effect, extraction recovery, and stability. The calibration curves were linear over 2-1000 ng/mL. The intra- and inter-day precision and accuracy of quality control samples were 4.79-13.33% and 86.23-102.75%, respectively. The matrix effect and extraction recovery were 96.11-98.47% and 96.11-102.25%, respectively. In the pharmacokinetic study after intravenous administration of damaurone D at a dose of 3 mg/kg in rats, the area under the curve and clearance of damaurone D in rat plasma were $16750.26{\pm}2676.10min{\cdot}ng/mL$ and $182.44{\pm}31.36mL/min/kg$, respectively.

Determination of Sulfur-Containing Odorants in Natural Gas by Gas Chromatography/Flame Photometric Detection (GC/FPD에 의한 천연가스 중 황 함유 부취제의 정량)

  • Choi, Yong-Wook;Kim, Jong-Hun;Choe, Kun-Hyung;Shin, Sung-Sik
    • Analytical Science and Technology
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    • v.7 no.3
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    • pp.349-359
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    • 1994
  • A gas chromatographic method for analyzing the gas odorants concentration in natural gas was studied. Eight odorants involving TBM and THT were completely separated by using OV-10 column. The optimization of several interrelated key parameters affecting the response of FPD such as hydrogen flow rate, air flow rate and detector temperature were accomplished. A permeation device was used to obtain calibration curves of TBM and THT. This analytical method has applied to measure TBM and THT used as a natural gas odorant blend in natural gas pipeline. In order to elucidate the relationship between odor level and odorant level feasibility test of fragrance meter was demonstrated.

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