• Journal of Korean Society for Atmospheric Environment
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• v.15 no.3
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• pp.223-233
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• 1999

The wind-flow characteristics over a two-dimensional triangular prism with a porous windbreak are numerically investigated. The geometry is a simplified model of large outdoor stack with a frontal wall-type windbreak which is used to prevent particle dispersion by reducing wind speed over stak surface. In the present numerical model, the RNG k-$\varepsilon$ model, the orthogonal grid system and the QUICK scheme are employed for the successful simulation of separated flow. The predicted results are compared and validated with the associated wind-tunnel experiments. In addition, the trajectories of dispersed particles and their sedimentation characteristics are quantitatively investingated using a Lagrangian turbulent-dispersion model.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.2
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• pp.230-237
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• 2024

Dispersion munitions are often equipped with dispersive submunitions used to scatter bombs over a wide area, and one of the types of dispersive submunitions is the Magnus rotor, commonly referred to as a self-rotating flying body. The Magnus rotor is designed to be dispered over a wide area by utilizing the principle of the Magnus effect through self-rotation, and has various trajectories depending on the initial conditions from the mother dispersion munition. In this paper, an index to evaluate the dispersion uniformity of footprint of the dispersive submunition is presented and the dispersion uniformity according to various initial release conditions is evaluated, and it is getting larger with high incidence angle and get max value at certain initial angular velocity.

• Korean Journal of Food Science and Technology
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• v.23 no.6
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• pp.759-763
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• 1991

The dynamic rheological properties of the dope and the hydrated disperson of the soyprotein, as a starting material of soyprotein fiber, were studied to investigate their viscoelastic properties. The increase of protein concentration in the both cases of the dope and the dispersion resulted in the establishment of intermolecular reaction of the protein. With the addition of alkali solution to the dispersion, the dope shows the characteristics of very lightly cross-linked high molecular weight polymer. In constrast, the dispersion shows the properties of an amorphorous polymer. The effects of chemical modification of the dispersion on the dynamic properties were also investigated.

• Journal of Environmental Science International
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• v.5 no.6
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• pp.699-712
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• 1996

For the efficient control of atmospheric quality, it is so important to predict the influence accurately of which the air pollutant emitted into the atmosphere. Atmospheric dispersion model enables to simulate and grasp the atmospheric condition occurred due to the emission of pollutants. The result of model is largely affected by the amount of emission, the characteristics of physical and chemical process, meteorological input data, and the receptor which the concentration is calculated. The aim of this research, therefore, is to suggest more suitable model in Pusan area than other areas by performing TCM2, CDM2.0 and ISCLT2 models. As the basic work for executing the model, we computed the amount of emission of air pollutants in Pusan at 1992 and analyzed the occurrence frequency of atmospheric stability for recent decade(1985~19941, CDM2.0 showed the similar result relatively with observed value in the case of full year(1992), fall and winter, and ISCLT2 brought more suitable result in spring for Pusan area. As the result of this research, in future, it is necessary for us to develop the numerical model considering the topographical characteristics, to select the proper observation site and to increase the observation site for Pusan.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.1 no.1
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• pp.77-90
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• 1981

This study involves 1) air quality disperson predictions and 2) a comparison of the predicted data with the actually measured ones in terms of annual sulfur dioxide concentration in the Ulsan Industial Complex. The prediction was made by utilizing the CDMQC air quality simulation computer model. The higher concentrations were observed at the Bugok Dong (Sampling Site) and the Yeochun Dong Sampling Site with the values of 44 and 46 ppb, respectively whereas the predicted values for both sites were 52 and 47 ppb, respectively. A statistical examination has revealed that the level of confidence was 90.02% from the Chi-squared test and the corelation coefficient was 0.827. It thus demonstrates that the model used for the study appears to be applicable to yield reliable predictions in terms of annual sulfur dioxide concentrations in the study area.

• Journal of the Korean Geotechnical Society
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• v.22 no.12
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• pp.15-24
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• 2006

The evaluation of shear modulus is very important in various fields of civil engineering. Non-destructive seismic methods can be used to determine shear wave velocity ($V_s$) profile. Non-destructive seismic methods geneally consist of three steps: field testing, evaluation of dispersion curve, and determination of Vs profile by inversion process. Non-destructive seismic methods can be divided into two categories according to the number of receivers used for data reduction: two-channel tests and multi-channel tests. Two channel tests use apparent velocity dispersion curve and multi-channel tests use mode dispersion curves. Multi-channel tests using mode dispersion curve can reduce calculation time to determine soil profile and uncertainties in inversion process. So far, only multi-channel tests can determine mode dispersion curves but multi-channel test needs many receivers to determine reasonable mode dispersion curves. In this paper, HWAW (Harmonic Wavelet Analysis of Wave) method is applied to determine mode dispersion curves. HWAW method uses short test setup which consists of two receivers with a spacing of 1 to 3 m. Through numerical simulations and field application, it is shown that HWAW can determine resonable mode disperson curves.