• Journal of Ocean Engineering and Technology
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• v.21 no.4
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• pp.45-54
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• 2007

In the context of auto-landing containers from a container ship to a truck or automatic guided vehicle and vice versa, this research investigates three schemes, one in Part I and two in Part II, for measuring the absolute position of a container. Coordinate transformations between the reference-coordinate, sensor-coordinate, and body-coordinate systems are briefly discussed. The scheme explored in Part I aims the use of three laser-slit sensors, which are relatively inexpensive. In this case, nine nonlinear equations are formulated for six unknown variables (three for orientation and three for position), so a closed-form solution is not available. Instead, an approximate solution through linearization was derived. An advantage of the method in Part I is its ability to measure an absolute position in 3D space, while a disadvantage is the computation time required to obtain pseudo-inverses and the approximate nature of the obtained solution. Numerical examples are provided.

• Journal of Environmental Science International
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• v.23 no.11
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• pp.1843-1850
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• 2014

PS-D2EHPA beads were prepared by immobilizing di-2-ethylhexyl-phosphoric acid (D2EHPA) with polysulfone (PSf). The removal experiments of Cu(II) and Pb(II) by the prepared PS-D2EHPA beads were conducted batchwise. The removal efficiency of Cu(II) and Pb(II) by PS-D2EHPA beads was increased with increasing pH of solution. The removal rate of Cu(II) and Pb(II) was well described by the pseudo-second-order kinetic model. The maximum removal capacity of Cu(II) and Pb(II) obtained from Langmuir isotherm were 2.58 mg/g and 12.63 mg/g, respectively. External mass transfer coefficients for the removal of Cu(II) and Pb(II) by PS-D2EHPA beads were obtained $0.61{\times}10^{-2}{\sim}5.87{\times}10^{-2}/min$ and $1.55{\times}10^{-2}{\sim}8.53{\times}10^{-2}/min$, respectively and diffusion coefficients were obtained $1.32{\times}10^{-4}{\sim}3.98{\times}10^{-4}cm^2/min$ and $1.80{\times}10^{-4}{\sim}2.28{\times}10^{-4}cm^2/min$, respectively.

• Journal of Environmental Science International
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• v.24 no.7
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• pp.841-849
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• 2015

The solid phase extractant SAN-D2EHPA/TBP containing two extractants of Di-(2-ethylhexyl)phosphoric acid (D2EHPA) and Tri-butyl-phosphate (TBP) was prepared by immobilizing two exractants D2EHPA and TBP in styrene acrylonitrile copolymer (SAN). The prepared SAN-D2EHPA/TBP was characterized by using fourier transform infrared spectrometer (FTIR) and scanning electron microscopy (SEM). The solid phase extractant SAN-D2EHPA/TBP was tested for the removal of Cu(II) from aqueous solution. Experiments were carried out as a function of the pH and Cu(II) concentration in the aqueous phase. The equilibrium time was 180 min and equilibrium experiment data obeyed the pseudo-second-order kinetic model. The Langmuir isotherm model represented the experiment data as well. The maximum removal capacity of Cu(II) calculated from Langmuir isotherm model was 3.1 mg/g.

• Journal of Ocean Engineering and Technology
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• v.17 no.5 s.54
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• pp.66-75
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• 2003

Long cylinder, subjected to internal pressure, is important in the analysis and design of nuclear fuel rod structures. In many cases, long cylinder problems have been considered as a plane strain condition. However, strictly speaking, long cylinder problems are not plane strain problems, but rather a general plane strain (GPS) condition, which is a combination of a plane strain state and a uniform strain state. The magnitude of the uniform axial strain is required, in order to make the summation of the axial force zero. Although there has been the GPS element, this paper proposes a general technique to solve long cylinder problems, using several pseudo-general plane strain (PGPS) elements. The conventional GPS elements and PGPS elements employed are as follows: axisymmetric GPS element (GA3), axisymmetric PGPS element (PGA8/6), 2-D GPS element (GIO), 3-D PGPS element (PG20/16), and reduced PGPS elements (RPGA6, RPG20/16). In particular, PGPS elements (PGA8/6, PG20/16) can be applied in periodic structure problems. These finite elements are tested, using several kinds of examples, thereby confirming the validity of the proposed finite element models.

• Structural Engineering and Mechanics
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• v.61 no.6
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• pp.795-806
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• 2017

According to the characteristics of continuous beam bridges, the relative displacement is too large to collision or even girder falling under earthquakes. A device named Cable-sliding Modular Expansion Joints(CMEJs) that can control the relative displacement and avoid collision under different ground motions is proposed. Working principle and mechanical model is described. This paper design the CMEJs, establish the restoring force model, verify the force model of this device by the pseudo-static tests, and describe and analyze results of the tests, and then based on a triple continuous beam bridge that has different heights of piers, a 3D model with or without CMEJs were established under Conventional System (CS) and Seismic Isolation System (SIS). The results show that this device can control the relative displacement and avoid collisions. The combination of isolation technology and CMEJs can be more effective to achieve both functions, but it need to take measures to prevent girder falling due to the displacement between pier and beam under large earthquakes.

• Environmental Engineering Research
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• v.25 no.4
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• pp.605-613
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• 2020

This study is to investigate the possibility of using activated carbon prepared from Iraqi date-pits (ADP) which are produced from palm trees (Phoenix dactylifera L.) as low-cost reactive material in the permeable reactive barrier (PRB) for treating lead (Pb⁺²) from the contaminated groundwater, and then compare the results experimentally with other common reactive materials such as commercial activated carbon (CAC), zeolite pellets (ZP). Factors influencing sorption such as contact time, initial pH of the solution, sorbent dosage, agitation speed, and initial lead concentration has been studied. Two isotherm models were used for the description of sorption data (Langmuir and Freundlich). The maximum lead sorption capacities were measured for ADP, CAC, and ZP and were found to be 24.5, 12.125, and 4.45 mg/g, respectively. The kinetic data were analyzed using various kinetic models particularly pseudo-first-order, pseudo-second-order, and intraparticle diffusion. COMSOL Multiphysics 3.5a depend on finite element procedure was applied to formulate transmit of lead (Pb⁺²) in the two-dimensional numerical (2D) model under an equilibrium condition. The numerical solution shows that the contaminant plume is hindered by PRB.

• Korea-Australia Rheology Journal
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• v.21 no.3
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• pp.193-200
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• 2009

We present a direct simulation technique for two-dimensional mold-filling simulations of fluids filled with a large number of circular disk-like rigid particles. It is a direct simulation in that the hydrodynamic interaction between particles and fluid is fully considered. We employ a pseudo-concentration method for the evolution of the flow front and the DLM (distributed Lagrangian multipliers)-like fictitious domain method for the implicit treatment of the hydrodynamic interaction. Both methods allow the use of a fixed regular discretization during the entire computation. The discontinuous Galerkin method has been used to solve the concentration evolution equation and the rigid-ring description has been introduced for freely suspended particles. A buffer zone, the gate region of a finite area subject to the uniform velocity profile, has been introduced to put discrete particles into the computational domain avoiding any artificial discontinuity. From example problems of 450 particles, we investigated the particle motion and effects of particles on the flow for both Newtonian and shear-thinning fluid media. We report the prolonged particle movement toward the wall in case of a shear-thinning fluid, which has been interpreted with the shear rate distribution.

• Journal of Broadcast Engineering
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• v.21 no.1
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• pp.3-10
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• 2016

In this paper, two reconstructed point cloud sets with the information of 3D features are analyzed. For a certain 3D reconstruction of the interior of a building, the first image set is taken from the sequential passive camera movement along the regular grid path and the second set is from the application of the laser scanning process. Matched key points over all images are obtained by the SIFT(Scale Invariant Feature Transformation) algorithm and are used for the registration of the point cloud data. The obtained results are point cloud number, average density of point cloud and the generating time for point cloud. Experimental results show the necessity of images from the additional sensors as well as the images from the camera for the more accurate 3D reconstruction of the interior of a building.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.2
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• pp.244-252
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• 1997

The pseudo-spinel type solid solution, $LiAl_{2.5}/Fe_{2.5}O_8$ was prepared by reaction of $LiCO_3, Al_2O_3, Fe_2O_3$ mixture at 1620K, which can be used for cathode material in lithium batteries. Its structure was investigated by Rietveld profile-analysis of XRD in detail. The space group of solid solution is $P4_3$32(a=8.1293$\AA$) and the final residual index of structure refinement was about 5%. Cations $Al^{3+}, Fe^{3+}$ are located at both tetra- and octahedral-coordination and $Li^+$ ions are occupied in the octahedral 4b-, 12d-site of the inverse spinel.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.11a
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• pp.63-66
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• 2010

본 논문은 차세데 3D-TV 방송을 위해 수정된 ATSC (Modified Advanced Television Systems Committee) 시스템 [1]에서 파일럿 (Pilot)을 이용한 채널 추정 대신, PN 시퀀스 (Pseudo-Noise Sequence)를 이용한 채널 추정 방식의 문제점에 대하여 2가지 방법으로 연구하였다. PN 시퀀스를 이용하여 채널을 추정하는 TDS-OFDM (Time Domain Synchronous - Orthogonal Frequency Division Multiplexing)시스템은 QAM (Quadrature Amplitude Modulation) 변조 방식을 사용하기 때문에 수신측 PN 시퀀스의 위상 변화가 일어나지 않는다. 하지만 수정된 ATSC 시스템에서 사용하는 VSB (Vestigial Side Band)변조 방식에서 직교위상 (Quadrature) 채널을 통해 전송되는 값은 동위상 (In-Phase) 채널을 통해 전송되는 값의 단순한 힐버트 변환 (Hilbert Transform)에 의해 생성되어 불규칙한 위상 변화가 발생한다. 따라서 수정된 ATSC 시스템에서 채널 추정을 위해 PN 시퀀스를 사용하게 된다면 상관 (Correlation) 특성을 잃어버릴 것이며 올바른 채널 임펄스 응답 (Channel Impulse Response)을 얻을 수 없다.