• Korean Journal of Agricultural Science
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• v.39 no.3
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• pp.421-425
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• 2012

The objective of this study was to improve the detection limit of rapid detection kit for Salmonella Typhimurium by image analysis system. The rapid detection kit was comprised of four elements: sample pad, conjugate pad, nitrocellulose pad and absorbent pad. Gold nanoparticle and Salmonella antibody were used as a tag and a receptor. Salmonella antibody and goat rabbit IgG antibody were used as test and control lines on nitrocellulose membrane. The color intensity of test line began to increase from $10^5CFU/mL$ of Salmonella sample. A multiple linear regression analysis was employed to explain the relationship between predicted and measured number of Salmonella cells. The developed model could successfully predict the cell number of Salmonella with validation against extra-experimental result.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.123-133
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• 2001

Since most of soil slopes are in an unsaturated state, it is necessary to consider the unsaturated characteristics of soil slopes, in order to obtain more reasonable results. Therefore in this study we supplemented a slope stability analysis program to consider them, based on the concept of limit equilibrium. We also applied an optimization technique to search for a failure surface. Besides, we carried out experiments to obtain the unsaturated soil properties required in the analysis with weathered granite soils. We formulated a nonlinear apparent cohesion relationship with the matrix suction to be able to apply the unsaturated shear strength characteristics to the stability analysis. In addition, we intended to obtain more accurate soil water characteristic curves(SWCC) by measuring the change in volume of the specimen in the SWCC tests. As a result, we could appropriately assess the change of the safety factor according to the rainfall intensity and duration, by considering the variation of suction, permeability, and shear strength caused by the infiltration of rainfall into slopes.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.2
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• pp.336-344
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• 2002

In this study, the flow and combustion characteristics of flat flame burner with twirler were investigated. There are several factors that define the characteristics of burner. Among them, the experiments was focused on swirl effect by four types of twirler in terms of flow structure, distribution of temperature and emission characteristics. In PIV(Particle Image Velocimetry) experiment, the less of swirl number, axial flow is dominant at the center. As swirl number increases, the flow develops along the burner tile and backward flow becomes stronger at center. From the combustion characteristics, as long as combustion load increases, blow-off limit was improved. But at the higher swirl number, the limit is decreased. At swirl number 0, the temperature is shown typical distribution of long flame burner. but swirl number increases, the temperature distribution is uniform in front of round tile. Therefore, the temperature distribution is coincided with flow structure. As excess air ratio increases, NO concentrations are high. But high swirl number gives rise to become low NO concentrations. The flame characteristics are comprised in wrinkled laminar-flame regime according to turbulence Reynolds number(Rel) and Damkohler number(Da).

• Animal Bioscience
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• v.34 no.12
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• pp.2012-2022
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• 2021

Objective: In most retail centers, primal pork cuts for sale are usually prepared into retail-ready slices and overwrapped with air-permeable plastic film. Also, meat of Korean native black pig (KNP) is reputed for its superior quality, however, its shelf life during retail display has not been studied. Thus, the objective of this study was to evaluate shelf life of prepackaged retail-ready KNP belly and shoulder butt slices during refrigerated display. Methods: Bellies and shoulder butt obtained at 24 h post-mortem from finishing KNP were used. Each belly or shoulder butt was manually cut into 1.5 cm-thick slices. The slices in each cut type were randomly taken and placed on white foam tray (2 slices/tray) overwrapped with polyvinyl chloride film. The retail-ready packages were then placed in a retail display cabinet at 4℃. Shelf life and sensory quality of the samples were evaluated on day 1, 3, 6, 9, 12, and 15 of display. Results: The shoulder butt reached the upper limit (20 mg/100 g) of volatile basic nitrogen for fresh meat after 9 days while, the belly remained within this limit throughout the display time (15 days). Both the cuts reached a thiobarbituric acid reactive substances level of above 0.5 mg malondialdehyde/kg after 9 days. The a^* (redness) values remained unchanged during first 9 days in both cuts (p>0.05). After 9 days, off-flavor was not found in either cut, but higher off-flavor intensity was found in shoulder butt after 12 days. The shoulder butt was unacceptable for overall eating quality after 12 days while, belly still was acceptable after 12 days. Conclusion: The belly showed a longer shelf life compared to the shoulder butt, and a shelf life of 9 and 12 days is recommended for the prepackaged retail-ready KNP shoulder butt and belly slices, respectively.

• Journal of the Korean GEO-environmental Society
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• v.15 no.8
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• pp.45-50
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• 2014

The microorganism decomposition experiment of sewage in the underground sewer has the limit of experiment condition and time. The way to reproduce the microorganism decomposition in the underground sewer was studied using batch reactor setting up the DO as a limiting condition. The DO concentration in the sewer is controlled by reaeration. It is possible to obtain correlation between flow condition and reaeration coefficient through the reproduction of reaeration phenomenon by controlling the flow condition in the sewer using this phenomenon. And it is possible to set the flow condition and agitation intensity (velocity gradient) that has the same reaeration coefficient using the correlation between the reaeration coefficient with the flow condition and reaeration coefficient with the agitation intensity. The circumstances in the sewer system was reproduced using batch reactor setting up the DO as a limiting condition from these results.

• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.6
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• pp.953-962
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• 1987

Domestic dissimilar structural steels, SM 45 C and SUS304 were friction welded under optimal welding condition and the micro-artificial holes were drilled at SM 45 C base metal, SM 45 C HAZ, welded zone, SUS 304 HAZ, and SUS 304 base metal for fatigue behavior tests. In this study, the fatigue limit and the behavior of micro-crack propagation, crack propagation rate, and its dependency on stress intensity factor under the low stress level and high stress level of bending stress have been investigated. The results obtained are as follows. (1) The fatgiue strength of the portion of SM45C B.M., SM45C HAZ, welded zune, SUS304 HAZ and SUS304 B.M. on notched friction welded specimens are 20 kgf/mm$^{2}$, 32 kgf/mm$^{2}$, 27kgf/mm$^{2}$, 29kgf/mm$^{2}$, and 29kgf/mm$^{2}$, respectively. (2) The fatigue strength of welded zone of unnotched and notched specimens are 32.5kgf/mm$^{2}$, and 27kgf/mm$^{2}$, respectively. (3) Micro-crack initiation in the welded zone, HAZ, and each base metals occurrs simultaneously in front and rear of micro-hole tips in the view of the rotational directions. (4) Fatigue crack propagates more slowly in the welded zone than in another protions of specimen, regardless of the magnitude of the stress level. (5) Fatigue crack propagation rates were plotted as a function of stress intensity range. The value of m in the equation da/dN=C(.DELTA.K)$^{m}$ was found to range from 2.09-2.55 in this study.

• Computers and Concrete
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• v.12 no.2
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• pp.211-228
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• 2013

The structure analyzed in this paper has particular building style and special structural system. It is a rigid-connected twin-tower skyscraper with asymmetrical distribution of stiffness and masses in two towers. Because of the different stiffness between the north and the south towers, the torsion seismic vibration is significant. In this paper, in order to study the seismic response of the structure under both frequent low-intensity earthquakes as well as rare earthquakes at the levels of intensity 7, the analysis model is built and analyzed with NosaCAD. NosaCAD is an nonlinear structure analysis software based on second-development of AutoCAD with ObjectARX. It has convenient modeling function, high computational efficiency and diversity post-processing functions. The deformations, forces and damages of the structure are investigated based on the analysis. According to the analysis, there is no damage on the structure under frequent earthquakes, and the structure has sufficient capacity and ductility to resist rare earthquakes. Therefore the structure can reach the goal of no damage under frequent earthquakes and no collapse under rare earthquakes. The deformation of the structure is below the limit in Chinese code. The time sequence and distribution of damages on tubes are reasonable, which can dissipate some dynamic energy. At last, according to forces, load-carrying capacity and damage of elements, there are some suggestions on increasing the reinforcement in the core tube at base and in stiffened stories.

• Journal of the Institute of Electronics Engineers of Korea TE
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• v.37 no.5
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• pp.77-84
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• 2000

In this paper, we modelized the multipath fading to Nakagami-m distribution fading channel which can be applied to the extended mobile communication channel environment. We assumed that the phase difference with reference signal happened in the received signal and in the receiver PLL(Phase Locked Loop) is the phase error. To correct the error we propose new RAKE receiver using PLL. In addition, we analyze the performance of DS/SS(Direct Sequence/spread Spectrum) system according to the gain of PLL,$\gamma_n$, the number of RAKE receiver branch L and MIP(Multipath Intensity Profile)'s exponential decay $\delta$. As a result, when the proposed RAKE receiver L Is increased and the $\delta$ is decreased the performance of the system gets better. Futhermore when PLL gain was 30dB, phase is identified. That is when the PLL gain is 30dB, the performance equals with the perfect coherent system's. Therefore, we can correct the phase error by using the proposed RAKE receiver and we proved that the PLL's requested limit gain should be 30dB.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.1007-1015
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• 2013

A stochastic probability model based on the non-homogeneous Poisson process is represented that can correctly analyze the time-dependent linear and nonlinear behaviors of total damage over the occurrence process of loads. Introducing several types of damage intensity functions, the probability of failure and the total damage with respect to mean time to failure has been investigated in detail. Taking particularly the limit state to be the random variables followed with a distribution function, the uncertainty of that would be taken into consideration in this paper. In addition, the stochastic probability model has been straightforwardly applied to the rubble-mound breakwaters with the definition of damage level about the erosion of armor units. The probability of failure and the nonlinear total damage with respect to mean time to failure has been analyzed with the damage intensity functions for armor units estimated by fitting the expected total damage to the experimental datum. Based on the present results from the stochastic probability model, the preventive management for the armor units of the rubble-mound breakwaters would be suggested to make a decision on the repairing time and the minimum amounts repaired quantitatively.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.4
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• pp.417-424
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• 2011

A fuel assembly consists of five major components, i.e., a top end piece (TEP), a bottom end piece (BEP), spacer grids (SGs), guide tubes (GTs) and an instrumentation tube (IT); in addition, it also includes fuel rods (FRs). The TEP/BEP should satisfy stress intensity limits according to the conditions A and B of ASME, Section III, Division 1-Subsection NB. In a dual-cooled fuel assembly, the array and position of fuel rods are different from those in a conventional PWR fuel assembly; these changes are necessary for achieving power uprating. The flow plates of the TEP and BEP have to be modified accordingly. The pattern and shape of the flow holes were newly designed. To verify the strength compatibility, the Tresca stress limit according to the ASME code was investigated in the case of an axial load of 22.241 kN. In this paper, the stress linearization procedure for strength evaluation of a newly designed TEP is presented.