• Korean Journal of Veterinary Service
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• v.21 no.2
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• pp.133-139
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• 1998

Serum samples collected from 30 breeders and their progeny 30 chicks. The antibodies against infectious bronchitis(IB), infectious bursal disease (IBD) and Newcastle disease(ND) viruses were detected by ELISA using commercial ELISA kit. The breeders were vaccinated against IB, IBD and ND viruses according to general vaccination program. Geometric mean titers(GMT) of ELISA were monitored from 1-day old to 17-day old chicks and compared with breeder chickens. The GMT of ELISA to IB, IBD and ND were declined half level of the breeder antibody titer at 6-, 8- and 7-day old. And, the GMT of ELISA to IB, IBD and ND were declined than that of protective titer at 6-, 1-, and 4-day old. Thereafter, the GMT of ELISA was declined and disappeared according to ages of chicks. Taken together, this study led to conclusion that time-course of maternal antibody titers of chicks from vaccinated breeders, and this is very important data for vaccination to chicks.

• Journal of Environmental Health Sciences
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• v.19 no.2
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• pp.34-39
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• 1993

One hundred and eighty-seven water samples were collected from 23 of spring water, 2 of ground water, 1 of tap water in Pusan area and 3 of natural mineral waters. Total coliform group, fecal coliform, viable cell count and microflora were investigated to evaluate water quality of drinking water. The results were as follows: range and geometric mean value of total coliform and fecal coliform MPN's of spring water were 0~1,500/100 ml, 85/100 ml and 0~460/100 ml, 24/100 ml but coliform group was not detected in the samples of tap water and natural mineral water. Viable cell count of spring water, ground water and tap water were lower as 100 cell than the criteria for drinking water but that of natural mineral water was higher as 6.5X 10$^2$~7.4X 10$^3$ /ml. Predominant speces among the 219 strains isolated from the samples were 19.6% Aeromonas spp., 19.2% Enterobacteriaceae, 16% Acinetobacter spp. Especially, spring water and vessels were contaminated by Hafnia spp. and Providencia Spp, inhabitant of the oral cavity.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.6
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• pp.1598-1603
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• 1994

A preliminary design procedure for a multi-stage axial compressor is developed, which is based on the stage-stacking method. It determines the flow coefficient which gives rise to the design conditions required such as pressure ratio, mass flow rate and rotational speed for a given specific mass flow rate at inlet to a compressor. With this flow coefficient, blade radii, every stage and compressor performance characterics such as stage pressure ratio, adiabatic efficiency etc. are calculated by stacking each stage performance characteristics. It is shown that there is an optimum number of stage which results in the maximum of compressor overall efficiency for a given specific mass flow rate at inlet to a compressor. A test design was tried for three different geometric design constraints, and comparison with a previous study shows that present procedure could be used reliably in determining the number of compressor stage in preliminary design stage.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.806-809
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• 2003

In this paper, extracting design information from arbitrary aspherical lens shape in reverse engineering is introduced. Deformation terms and sphere data equation with various variables compose asphere equation. Aspherical lens shape is expressed with complicated polynomial expression that includes deformation terms and sphere data. Deformation term and vertex curvature have direct influence on a geometric shape and an optical characteristics of aspherical lens. Hence, extracting these information mean that design information could be derived and analyzed from shape data of arbitrary aspherical lens. Furthermore, sharing designer's experience and knowledge for aspherical lens design could be expected.

• Journal of Advanced Marine Engineering and Technology
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• v.30 no.2
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• pp.311-318
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• 2006

In this study, the performance tests for single and dual micro processor configurations are performed to investigate how the accelerated OpenGL components and applications are dependent on processor configurations. At present, many major providers of the engineering graphics workstations have recommended that multiprocessors are better than single processor. However, we confirmed that the single processor configuration is more faster and more effective than competitive configurations and suggested the economic method to improve the performance of the engineering graphics workstations.

• Structural Engineering and Mechanics
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• v.54 no.2
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• pp.221-237
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• 2015

An integrated method is proposed for structural nonlinear damage detection based on time series analysis and the higher statistical moments of structural responses in this study. It combines the time series analysis, the higher statistical moments of AR model residual errors and the fuzzy c-means (FCM) clustering techniques. A few comprehensive damage indexes are developed in the arithmetic and geometric mean of the higher statistical moments, and are classified by using the FCM clustering method to achieve nonlinear damage detection. A series of the measured response data, downloaded from the web site of the Los Alamos National Laboratory (LANL) USA, from a three-storey building structure considering the environmental variety as well as different nonlinear damage cases, are analyzed and used to assess the performance of the new nonlinear damage detection method. The effectiveness and robustness of the new proposed method are finally analyzed and concluded.

• Earthquakes and Structures
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• v.3 no.6
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• pp.869-887
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• 2012

Ground motion scaling techniques are actively debated in the earthquake engineering community. Considerations such as what amplitude, over what period range and to what target spectrum are amongst the questions of practical importance. In this paper, the effect of various ground motion scaling approaches are explored using three reinforced concrete prototypical building models of 8, 12 and 20 stories designed to respond nonlinearly under a design level earthquake event in the seismically active Southern California region. Twenty-one recorded earthquake motions are selected using a probabilistic seismic hazard analysis and subsequently scaled using four different strategies. These motions are subsequently compared to spectrally compatible motions. The nonlinear response of a planar frameidealized building is evaluated in terms of plasticity distribution, floor level acceleration and uncorrelated acceleration amplification ratio distributions; and interstory drift distributions. The most pronounced response variability observed in association with the scaling method is the extent of higher mode participation in the nonlinear demands.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11a
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• pp.504-511
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• 2001

In this research, we developed a computer program that designs a centrifugal impeller and diffuser, and predicts the far-field noise from the impeller. To design the impeller optimally, the TEIS model, which was originally developed by Japkise(1985), and the mean-line analysis are combined to predict the performance and design the optimal impeller simultaneously. The geometric configurations are provided by a GUI software (iDesignComp). The noise from impeller can be computed by the rapid loading procedure, which generates a surface between two blades and calculates the pressure distributions on the suction and pressure sides. The steady loading noise is computed by the rotating dipole source distribution via Ffowcs Williams & Hawkings equation.

• Journal of Environmental Health Sciences
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• v.14 no.2
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• pp.13-27
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• 1988

Two asbestos slate manufacturing and seven asbestos textile plants in Korea were surveyed from May 20 to July 2, 1987. The purposes of this study were to evaluate 1) worker exposure to asbestos, 2) compliance to the standards and 3) the efficiency of existing local exhaust systems. Sixty-two personal samples and eighty-three area samples were collected and analyzed using "NIOSH 7400" method. Results of this study were as follows. 1. The asbesots exposure concentrations in asbestos textile plants were 1.3 - 14.3 fibers/cc(geometric mean(GM), 4.4 fibers/cc). 2. Worker exposure level to asbestos fiber in asbestos slate manufacturing industry was 0.21 fibers/cc during wet processing, which is below the Korean Standard of 2 fibers/cc. 3. Most local exhaust systems installed in asbestos textile plants were inadequately designed. 4. Ninety-six percent of the 145 samples exceeded the U.S. Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (PEL) of 0.2 fibers/cc and forty-nine percent of the samples exceeded the Korean Standatd of 2 fibers/cc.

• Journal of computational fluids engineering
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• v.14 no.3
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• pp.49-55
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• 2009

This study focuses on the near-field vortical structure and dynamics of coaxial jets. The characteristics of laminar flow and mixing in coaxial jets are investigated using a unsteady flow simulation. In order to analyze the geometric effects on the vortical structure, several cases of different configurations are selected for various values of the velocity ratio of inner jet to outer jet. From the result, it is confirmed that the flow mixing is promoted by the development of vortical structure and the interaction between inner jet and outer jet. This feature is strongly related to the vortex frequency in the shear-layers. The vortex frequency depends on the velocity ratio and the lip thickness of inner nozzle, but the outer pipe length has no effect on the frequency variation.