• Magazine of the Korean Society of Agricultural Engineers
• /
• v.33 no.2
• /
• pp.51-60
• /
• 1991

The main objective of this study is to examine the adaptability for the large watershed of the storage tank model which can be applied for the analysis of both long and short terms runoff developed on the basis of hydrologic data for a smaH mountaineous watershed. The results obtained in this study are summarized as follows ; 1. Areal rainfalls of the Dae Chong watershed were calculated by Thiessen method composed of 9 Thiessen networks. 2. Optimal parameters for two types, Model A and Model B of tank models were derived through calibration procedure by standardized Powell method. 3. Monthly simulated flows of Model B are seemed to be closer to the monthly observed than those of Model A during calibration period in the long terms runoff. 4. Relative errors for the simulated flood flows of Model B were apperaed as lower percentage to the observed than those of Model A during calibration period in the short terms runoff. 5. Daily simulated hydrographs of Model B are seemed to be closer to the daily observed than those of Model A during verification period in the long terms runoff. Significance of Model B was highly acknowledged in comparison with Model A in the correlation analysis between annual observed and annual simulated runoff. 6. Reproducibility of simulated flows for Model B is generally seemed to be better than that of Model A during calibration period in the short terms runoff. 7. It can be concluded that reproducibility of Model B is superior to that of Model A in the long and short terms runoff even a large watershed like the result of the small one. 8. It was verified that adaptability for the large watershed of Model B is superior to that of Model A between the two models which were developed by a small watershed characteristics for both long and short terms runoff. 9. Further study for getting a suitable tank model is desirable to be established by the decision, calibration method of initial parameters of tank model and by additional application of another watershed with different watersheds and meterological characteristics.

• Journal of Microbiology and Biotechnology
• /
• v.27 no.2
• /
• pp.297-305
• /
• 2017

The use of peroxidase in the nitration of phenols is gaining interest as compared with traditional chemical reactions. We investigated the kinetic characteristics of phenol nitration catalyzed by horseradish peroxidase (HRP) in an aqueous-organic biphasic system using n-butanol as the organic solvent and ${NO_2}^-$ and $H_2O_2$ as substrates. The reaction rate was mainly controlled by the reaction kinetics in the aqueous phase when appropriate agitation was used to enhance mass transfer in the biphasic system. The initial velocity of the reaction increased with increasing HRP concentration. Additionally, an increase in the substrate concentrations of phenol (0-2 mM in organic phase) or $H_2O_2$ (0-0.1 mM in aqueous phase) enhanced the nitration efficiency catalyzed by HRP. In contrast, high concentrations of organic solvent decreased the kinetic parameter $V_{max}/K_m$. No inhibition of enzyme activity was observed when the concentrations of phenol and $H_2O_2$ were at or below 10 mM and 0.1 mM, respectively. On the basis of the peroxidase catalytic mechanism, a double-substrate ping-pong kinetic model was established. The kinetic parameters were ${K_m}^{H_2O_2}=1.09mM$, ${K_m}^{PhOH}=9.45mM$, and $V_{max}=0.196mM/min$. The proposed model was well fit to the data obtained from additional independent experiments under the suggested optimal synthesis conditions. The kinetic model developed in this paper lays a foundation for further comprehensive study of enzymatic nitration kinetics.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.32 no.2
• /
• pp.165-169
• /
• 1999

Experiments were conducted to evaluate a experimental model developed for the protein removal by foam separation. The foam separator was operated in well-mixed tank which would be considered as a completely mixed condition. The feasibility of foam separation to remove protein from sea water was investigated. Protein removal characteristics of the foam separator were obtained by batch experiments. To find the effect of the operating parameter to protein removal rate, the foam separation was carried with variation of initial protein concentration and superficial air velocity. The result indicated that the protein removal efficiency was increased with increasing protein concentration and superficial air velocity. The relationship between operation parameters and protein removal rate were evaluated by non-linear regression as the form of exponential function, Using both relationships, the simplified model was determined. The simplified foam separator operation model was verified by the batch operation. The simulation results showed a good relationship with the experimental data.

• Journal of Radiation Protection and Research
• /
• v.27 no.3
• /
• pp.165-170
• /
• 2002

Combined with deposition model onto the ground of radionuclides, the influence of radioactive contamination to agricultural products was analyzed due to wet deposition as well as dry deposition from radioactive air concentration during a nuclear emergency. The previous dynamic food chain model, in which initial input parameter is only radionuclide concentrations on the ground, was improved for the evaluating of radioactive contamination to agricultural products from either radionuclide concentrations in air or radionuclide concentrations on the ground. As the results, in case of deposition onto the ground, wet deposition was more dominant process than thy deposition. While the contamination levels of agricultural products were dependent on the a variety of factors such as radionuclides and rainfall rate. It means that the contamination levels of agricultural products are determined from which is more dominant process between deposition on the ground and interception onto agricultural plants.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2009.09a
• /
• pp.157-171
• /
• 2009

A 151 storey super high-rise building located in an area of reclaimed land constructed over soft marine clay in Songdo, Korea is currently under design. This paper describes the design process of the foundation system of the supertall tower, which is required to support the large building vertical and lateral loads and to restrain the horizontal displacement due to wind and seismic forces. The behaviour of the foundation system due to these loads and foundation stiffness influence the design of the building super structure, displacement of the tower, as well as the raft foundation design. Therefore, the design takes in account the interactions between soil, foundation and super structure, so as to achieve a safe and efficient building performance. The site lies entirely within an area of reclamation underlain by up to 20m of soft to firm marine silty clay, which overlies residual soil and a profile of weathered rock. The nature of the foundation rock materials are highly complex and are interpreted as possible roof pendant metamorphic rocks, which within about 50m from the surface have been affected by weathering which has reduced their strength. The presence of closely spaced joints, sheared and crushed zones within the rock has resulted in deeper areas of weathering of over 80m present within the building footprint. The foundation design process described includes the initial stages of geotechnical site characterization using the results of investigation boreholes and geotechnical parameter selection, and a series of detailed two- and three-dimensional numerical analysis for the Tower foundation comprising over 172 bored piles of varying length. The effect of the overall foundation stiffness and rotation under wind and seismic load is also discussed since the foundation rotation has a direct impact on the overall displacement of the tower.

• Journal of the Korean Geotechnical Society
• /
• v.36 no.8
• /
• pp.49-60
• /
• 2020

A fully coupled thermo-hydro-mechanical model is established to evaluate frost heave behaviour of saturated frost-susceptible soils. The method is based on mass conservation, energy conservation, and force equilibrium equations, which are fully coupled with each other. These equations consider various physical phenomena during one-dimensional soil freezing such as latent heat of phase change, thermal conductivity changes, pore water migration, and the accompanying mechanical deformation. Using the thermo-hydro-mechanical model, a sensitivity analysis study is conducted to examine the effects of the geotechnical parameters and external conditions on the amount of frost heave and frost heaving rate. According to the results of the sensitivity analysis, initial void ratio significantly affects each objective as an individual parameter, whereas soil particle thermal conductivity and temperature gradient affect frost heave behaviour to a greater degree when applied simultaneously. The factors considered in this study are the main factors affecting the frost heaving amount and rate, which may be used to determine the frostbite sensitivity of a new sample.

• Proceedings of the KIPE Conference
• /
• 2005.07a
• /
• pp.261-265
• /
• 2005

This paper describes the DC-DC Converter for Ancillary Power Supply in Hybrid Electric Vehicle. DC-DC Converter is used for charging 12V auxiliary battery supplying electric power to head ramp, audio, ECU etc in automobiles. used DC-DC Converter Topology is PS-ZVS FB(Phase Shifted Zero Voltage Switching Full-Bridge) to reduce switching loss and EMI noise induced by high frequency operating condition. And For easy compensation and stable system response characteristic, current mode control method including slope compensation is employed. Constant current / constant voltage charging control method guarantee stable electric charging of auxiliary battery. Simulation toll PSIM6.0 is used for initial circuit parameter settings and H/W debuging. Thermal problems of Switching components in DC-DC Converter is improved by using Thermo Tracer.

• Structural Engineering and Mechanics
• /
• v.32 no.2
• /
• pp.193-212
• /
• 2009

The resilience of a city confronted with a terrorist bomb attack is the background of the paper. The resilience strongly depends on vital infrastructure and the physical protection of people. The protection buildings provide in case of an external explosion is one of the important elements in safety assessment. Besides the aspect of protection, buildings facilitate and enable many functions, e.g., offices, data storage, -handling and -transfer, energy supply, banks, shopping malls etc. When a building is damaged, the loss of functions is directly related to the location, amount of damage and the damage level. At TNO Defence, Security and Safety methods are developed to quantify the resilience of city infrastructure systems (Weerheijm et al. 2007b). In this framework, the dynamic response, damage levels and residual bearing capacity of multi-storey RC buildings is studied. The current paper addresses the aspects of dynamic response and progressive collapse, as well as the proposed method to relate the structural damage to a volume-damage parameter, which can be linked to the loss of functionality. After a general introduction to the research programme and progressive collapse, the study of the dynamic response and damage due to blast loading for a single RC element is described. Shock tube experiments on plates are used as a reference to study the possibilities of engineering methods and an explicit finite element code to quantify the response and residual bearing capacity. Next the dynamic response and progressive collapse of a multi storey RC building is studied numerically, using a number of models. Conclusions are drawn on the ability to predict initial blast damage and progressive collapse. Finally the link between the structural damage of a building and its loss of functionality is described, which is essential input for the envisaged method to quantify the resilience of city infrastructure.

• Smart Structures and Systems
• /
• v.26 no.3
• /
• pp.345-360
• /
• 2020

Modern swarm intelligence heuristic search methods are widely applied in the field of structural health monitoring due to their advantages of excellent global search capacity, loose requirement of initial guess and ease of computational implementation etc. To this end, a hybrid strategy is proposed based on butterfly optimization algorithm (BOA) and differential evolution (DE) with purpose of effective combination of their merits. In the proposed identification strategy, two improvements including mutation and crossover operations of DE, and dynamic adaptive operators are introduced into original BOA to reduce the risk to be trapped in local optimum and increase global search capability. The performance of the proposed algorithm, hybrid butterfly optimization and differential evolution algorithm (HBODEA) is evaluated by two numerical examples of a simply supported beam and a 37-bar truss structure, as well as an experimental test of 8-story shear-type steel frame structure in the laboratory. Compared with BOA and DE, the numerical and experimental results show that the proposed HBODEA is more robust to detect the reduction of stiffness with limited sensors and contaminated measurements. In addition, the effect of search space, two dynamic operators, population size on identification accuracy and efficiency of the proposed identification strategy are further investigated.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.35 no.10
• /
• pp.1025-1031
• /
• 2011

Autoignition characteristic is an important parameter for designing diesel or PCCI engines. In particular, diesel spray flames are lifted from the nozzle and the initial flame is formed by an autoignition phenomenon. The lifted nature of diesel spray flames influences soot formation, since air will be entrained into the spray core by the entrainment of air between the nozzle region and the lifted flame base. The objective of the present study was to identify the effect of heat loss on the ignition delay time by adopting a coflow jet as a model problem. Methane ($CH_4$), ethylene ($C_2H_4$), ethane ($C_2H_6$), propene ($C_3H_6$), propane ($C_3H_8$), and normal butane (n-$C_4H_{10}$) fuels were injected into high temperature air, and the liftoff height was measured experimentally. As the result, a correlation was determined between the liftoff height of the autoignited lifted flame and the ignition delay time considering the heat loss to the atmosphere.