• Korean Journal of Veterinary Service
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• v.20 no.4
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• pp.339-348
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• 1997

The purpose of the survey were determined the residual antibiotics and tetracyclines in beef(n=1,364), pork(n=2,817) and chickens(n=1,921) by the EEC 4-plate method, Charm IIand HPLC. The results were summarized as follows ; 1. The recovery rates in spiked samples were 98.8-107.2% for oxytetracycline(OTC), 33.2-48.6% for tetracycline(TC) and 64.1-72.3% for chlortetracycline(CTC) at 0.05-0.1ppm by HPLC using MSPD. 2. Residues of antibiotic were detected from 10 beef(0.75%) and 36 pork(1.31%) by EEC 4-plate method. In case of chickens were not detected. 3. Twenty-eight from 46 positive samples by the EEC 4-plate method were classified as TCs(60.9 %) by Charm II and TC of 12 samples were detected by HPLC. 4. Ten samples were detected levels of OTC ranging from 0.035 to 0.635 ppm and 3 samples were levels of CTC ranging from 0.066 to 0.150 ppm. OTC and CTC levels in 3 beef and 4 pork samples were exceeded the current tolerance level of 0.1 ppm.

• Journal of the Society of Naval Architects of Korea
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• v.49 no.5
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• pp.410-415
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• 2012

An experimental study is carried out to investigate the near-wake characteristics of a NACA 0018 foil with a flat plate. Two-frame grey-level cross correlation PIV method is used to measure the local flow characteristic around a pitch damping foil to control the vertical motion of high speed crafts in a circulating water channel. The analysis also includes angles of attack 10 and 20 degrees respectively. Reynolds number $Re{\fallingdotseq}3.5{\times}10^4$ based on the chord length(C=100mm) of NACA0018 has been applied during the whole experiments. The distance between the foil and the flat plate is D/C=0.5, 1.0 and 1.5 respectively. The channel effect according as the distance between the foil and the flat plate has a close relation with the velocity distributions around the foil. In the wake of 20-degree of attack, the complex turbulent flow and a thick boundary layer are formed due to the processes of vortex generation and dissipation.

• Earthquakes and Structures
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• v.13 no.5
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• pp.473-484
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• 2017

The objective of this paper is to report on a study of the use of unstiffened thin steel plate shear walls (SPSWs) for the seismic performance improvement of reinforced concrete frames with deficient lateral rigidity. The behaviour of reinforced concrete frames during seismic activities was rehabilitated with an alternative and occupant-friendly retrofitting scheme. The study involved tests of eight 1/3 scale, one bay, two storey test specimens under cyclic quasi-static lateral loadings. The first specimen, tested in previous test program, was a reference specimen, and in seven other specimens, steel infill plates were used to replace the conventional infill brick or the concrete panels. The identification of the load-deformation characteristics, the determination of the level of improvement in the overall strength, and the elastic post-buckling stiffness were the main issues investigated during the quasi-static test program. With the introduction of the SPSWs, it was observed that the strength, stiffness and energy absorption capacities were significantly improved. It was also observed that the experimental hysteresis curves were stable, and the composite systems showed excellent energy dissipation capacities due to the formation of a diagonal tension field action along with a diagonal compression buckling of the infill plates.

• Korean Journal of Veterinary Service
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• v.25 no.3
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• pp.285-294
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• 2002

The present studies were carried out to determine antibiotics residues in pork and beef muscles by EEC-4-plate and HPLC. A total of 2,534 samples of pork muscles and 1,070 samples of beef muscles from slaughter houses were collected in Gyeongnam area from January to December, 2001. The results were summarized as follows; 1. Recovery rates of TCs, Sulfa drug, Penicillin G from fortified pork and beef muscles ranged as 68.79～98.24%, 78.21～94.58% and penicillin G 63.35～67.24% respectively, by HPLC. 2. Antibiotics residues were detected in 36 sample(1.42%) of pork muscles, 29 sample (2.71%) of beef muscles by EEC-4-plate. 3. Detection rate of antibiotic residues 14 samples(0.55%) and 26 samples(2.43%), in pork and beef muscles, respectively by HPLC. Concentration of residues in 22 sample(2.06%) of beef muscle were higher than tolerance level in korea. 4. Antibiotics detected were sulfamethazine(47.37%), tetracycline(15.79%), oxytetracycline (15.79%), penicillin G(15.79%), sulfamerazine(5.26%) in pork muscle samples and oxyteracycline (37.21%), penicillin G(30.23%), sulfamethazine(20.93%), tetracycline(4.65%), sulfamerazine (2.33%), sulfadimethoxine(2.33%), sulfaquinoxine(2.33%) in beef muscle samples.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.732-739
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• 2005

The determination of sound pressure radiated from periodic plate structures is fundamental in the estimation of noise level in aircraft fuselages or ship hull structures. As a robust approach to this problem, here a very general and comprehensive analytical model is developed for predicting the sound radiated by a vibrating plate stiffened by periodically spaced orthogonal symmetrical beams subjected to a sinusoidally time varying point load. In this these, we experiment with the numerical analysis using the space harmonic series and the SYSNOISE for measuring the vibration mode and character of response caused by sound radiation with adding the harmonic point force in the thin isotropic plate supported by the rectangular lattice reinforcement. We used the reinforcements, beams of open type section like the style of 'ㄷ' letter; the space of the beams were chosen to be 0.2m, 0.3m, 0.4m. We studied the behavior of sound pressure levels, analysis of vibration mode between support points, connection between frequency function and sound pressure levels, and connection between position function and sound pressure levels.

• Advances in nano research
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• v.5 no.2
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• pp.69-97
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• 2017

In this study, nonlinear response of laminated functionally graded carbon nanotube reinforced composite (FG-CNTRC) plate under low-velocity impact based on the Eshelby-Mori-Tanaka approach in thermal conditions is studied. The governing equations are derived based on higher-order shear deformation plate theory (HSDT) under von $K\acute{a}rm\acute{a}n$ geometrical nonlinearity assumptions. The finite element method with 15 DOF at each node and Newmark's numerical integration method is applied to solve the governing equations. Four types of distributions of the uniaxially aligned reinforcement material through the thickness of the plates are considered. Material properties of the CNT and matrix are assumed to be temperature dependent. Contact force between the impactor and the laminated plate is obtained with the aid of the modified nonlinear Hertzian contact law models. In the numerical example, the effect of layup (stacking sequence) and lamination angle as well as the effect of temperature variations, distribution of CNTs, volume fraction of the CNTs, the mass and the velocity of the impactor in a constant energy level and boundary conditions on the impact response of the CNTRC laminated plates are investigated in details.

• Earthquakes and Structures
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• v.10 no.1
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• pp.1-23
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• 2016

Steel plate shear walls (SPSWs) have been shown to be efficient lateral force-resisting systems, which are increasingly used in new and retrofit construction. These structural systems are designed with either stiffened and stocky or unstiffened and slender web plates based on disparate structural and economical considerations. Based on some limited reported studies, on the other hand, employment of low yield point (LYP) steel infill plates with extremely low yield strength, and high ductility as well as elongation properties is found to facilitate the design and improve the structural behavior and seismic performance of the SPSW systems. On this basis, this paper reports system-level investigations on the seismic response assessment of multi-story SPSW frames under the action of earthquake ground motions. The effectiveness of the strip model in representing the behaviors of SPSWs with different buckling and yielding properties is primarily verified. Subsequently, the structural and seismic performances of several code-designed and retrofitted SPSW frames with conventional and LYP steel infill plates are investigated through detailed modal and nonlinear time-history analyses. Evaluation of various seismic response parameters including drift, acceleration, base shear and moment, column axial load, and web-plate ductility demands, demonstrates the capabilities of SPSW systems in improving the seismic performance of structures and reveals various advantages of use of LYP steel material in seismic design and retrofit of SPSW systems, in particular, application of LYP steel infill plates of double thickness in seismic retrofit of conventional steel and code-designed SPSW frames.

• Structural Engineering and Mechanics
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• v.86 no.1
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• pp.69-83
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• 2023

Analytical solutions to problems are crucial because they provide high-quality comparison data for assessing the accuracy of numerical solutions. Benchmark analytical solutions for the vibrations of cracked functionally graded material (FGM) plates are not available in the literature because of the high level of complexity of such solutions. On the basis of first-order shear deformation plate theory (FSDT), this study proposes analytical series solutions for the vibrations of FGM rectangular plates with side or internal cracks parallel to an edge of the plates by using Fourier cosine series and the domain decomposition technique. The distributions of FGM properties along the thickness direction are assumed to follow a simple power law. The proposed analytical series solutions are validated by performing comprehensive convergence studies on the vibration frequencies of cracked square plates with various crack lengths and under various boundary condition combinations and by performing comparisons with published results based on various plate theories and the theory of three-dimensional elasticity. The results reveal that the proposed solutions are in excellent agreement with literature results obtained using the Ritz method on the basis of FSDT. The paper also presents tabulations of the first six nondimensional frequencies of cracked rectangular Al/Al2O3 FGM plates with various aspect ratios, thickness-to-width ratios, crack lengths, and FGM power law indices under six boundary condition combinations, the tabulated frequencies can serve as benchmark data for assessing the accuracy of numerical approaches based on FSDT.

• Advances in materials Research
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• v.11 no.2
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• pp.91-109
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• 2022

This paper presents a closed-form higher-order analysis of interfacial shear stresses in RC continuous beams strengthened with bonded prestressed laminates. For retrofitting reinforced concrete continuous beams is to bond fiber reinforced prestressed composite plates to their tensile faces. An important failure mode of such plated beams is the debonding of the composite plates from the concrete due to high level of stress concentration in the adhesive at the ends of the composite plate. The model is based on equilibrium and deformations compatibility requirements in and all parts of the strengthened beam, where both the shear and normal stresses are assumed to be invariant across the adhesive layer thickness. In the present theoretical analysis, the adherend shear deformations are taken into account by assuming a parabolic shear stress through the thickness of both the RC continuous beams strengthened with bonded prestressed laminates. The theoretical predictions are compared with other existing solutions. A parametric study has been conducted to investigate the sensitivity of interface behavior to parameters such as laminate stiffness and the thickness of the laminate where all were found to have a marked effect on the magnitude of maximum shear and normal stress in the composite member.

• Journal of applied mathematics & informatics
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• v.42 no.3
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• pp.607-623
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• 2024

This article studies the effects of heat generation/absorption and thermal radiation on the unsteady magnetohydrodynamic (MHD) Casson fluid flow past a vertical plate through rotating porous medium with constant temperature and mass diffusion. It is assumed that the plate temperature and concentration level are raised uniformly. For finding the exact solution, a set of non-dimensional partial differential equations is solved analytically using the Laplace transform technique. The influence of various non-dimensional parameters on the velocity are discussed, including the effects of the magnetic parameter M, heat generation/absorption Q, thermal radiation parameter R, Prandtl number Pr, Schmidt number Sc, permeability of porous medium parameter, Casson fluid parameter γ, on velocity, temperature, and concentration profiles, which are discussed through several figures. It is found that velocity, temperature, and concentration profiles in the case of heat generation parameter Q, Casson fluid parameter γ, thermal Grashof number Gr, mass Grashof number Gc, Permeability Porous medium parameter K, and time t have retarding effects. It is also seen that the magnetic field M, Thermal Radiation parameter R, Prandtl field Pr, Schmidt number Sc have reverse effects on it.