• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3774-3778
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• 2012

A dynamic simulation of a fully thermally coupled distillation is conducted for the design of a possible operation scheme, and its performance is examined with an example process of reformate fractionation process. The outcome of the dynamic simulation indicates that the column can be operated by using a $3{\times}3$ control structure. The structure consists of three controlled variables of the compositions of overhead, side products and bottom and three manipulated variables of the flow rate of reflux, liquid split ratio between a main column and a prefractionator and steam.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.7
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• pp.105-113
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• 2022

In this study, a variable displacement swash plate pump supplying high-pressure hydraulic oil to control the hydraulic system of a marine engine was developed. A structural analysis was performed on the main parts of the pump to ensure the structural safety in the design. Using a pump testing equipment, performance characteristics such as no-load flow rate, load flow rate, flow rate according to the swivel angle change, flow rate with lubrication orifice, and response time according to the swivel motion were tested. Consequently, the pump was confirmed to satisfy the required specifications.

• Journal of The Korean Society of Grassland and Forage Science
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• v.20 no.2
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• pp.123-130
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• 2000

This study was carried out to examine the effects of animal manure on efficiency of the nitrogen utilization of silage corn (Zea mays L.) and soil fertility. The experiment was conducted on the field plot at Gongiam, Kwangju, Kyunggi-Do for 3 years, from 1996 to 1998, and arranged in split-plot design with three replications. The main plots were two kinds of composts such as swine manure fermented with sawdust (SMFWS) and swine manure fermented without sawdust (SMF). Subplots were the nitrogen fertilization rate (0, 100, 200, 300 and 400kgNhalyear). The nitrogen (N) yield increased as the nitrogen fertilization rate increased up to a rate of 300 kg Nha, but decreased at rate of 400 kg Nlha. Nitrogen yield in SMF treatments was higher than that of SMFWS treatments. But there were no significant differences between SMFWS and SMF treatments. Organic matter (OM) content of the soils in SMFWS was higher than that of SMF, &d was not significantly different between SMFWS and SMF treatments. OM content increased with increasing the nitrogen fertilization rate. Total nitrogen (TN) content of the soils increased as the nitrogen fertilization rate increased. No difference of TN content was found between SMFWS and SMF treatments. (Key words : Swine manure, Compost, Corn, Sawdust, Nutritive value)

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.30
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• pp.145-174
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• 2006

An anti-dumping has become the trade policy of choice for developing countries as well as advanced countries, hence it is the impending issue to the export-oriented countries including Korea. After colligating the analysis on the trade and industrial policy between Korea and China as well as the analysis on the preceding research, the main reasons of anti-dumping were selected as followings; an unemployment rate, real GDP growth rate and consumer price increase as internal factors, and trade balance, regional coefficient and trade specification index as external factors. Then, the research on how the above seven variable factors can affect the number of anti-dumping measures was accomplished. For the empirical analysis, the above information was used after reorganizing them by on the quarterly basis. Through the use of the correlation analysis, backward elimination of multiple regression analysis model and time-series analysis, it has appeared that the unemployment rate appeared to be the most important factors of anti-dumping measures in addition to the increase rate of trade balance. The variable such as the unemployment rate is uncontrollable for us, so it is appropriate to establish and operate an preemptive monitoring system based on the increasing rate of the amount of export and increasing rate of trade surplus.

• Journal of Power System Engineering
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• v.18 no.1
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• pp.38-44
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• 2014

The objectives of this study are to measure the ball recovery rate of cleaning apparatus for plate heat exchanger. Ceramic ball is used for plate heat exchanger cleaning. The main components of cleaning apparatus are comprised of ball collector, ball trap, ejector, pump and plate heat exchanger. The ball recovery rate are obtained with change in recovery time and velocity of water. The results show that the ball recovery rate is slightly increased with increase in the recovery time and the velocity of water over 0.4 m/s in the straight flow. In the case of reverse flow, the ball recovery rate more increased than straight flow. The maximum ball recovery rate of the straight flow and reverse flow reach 83.97% and 86.61%, respectively, when the velocity and cleaning time are 0.5 m/s and 15min.

• Health Policy and Management
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• v.8 no.2
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• pp.76-87
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• 1998

This study analyzed the effect of foreign currency exchange rate on the increasing rate of medical care cost by items of fee schedule of Korean Medical Insurance. This study uses the data of cost analysis including cost of imported goods and the data of for a university hospital National Federation's Medical Insurance for a trend of claim. The method of cost analysis is as same as that used in the study of the development of Korean RBRVS(Resource Based Relative Valus Scale). The main findings of this study are as follows; 1. The proportion of imported goods in cost related to Medical Insurance fee schedule is 7.93%, and in case of substitution of available domestic goods 6.96%. 2. If foreign currency exchange rate changes from 800wen per $1 to 1,300won, the affecting rate of Medical Insurance fee schedules is 5.00%. If the imported goods will be substituted with available domestic goods, the rate 4.35%. Our results can be used a data for updating Medical Insurance fee schedule. But this result is limited to be generalized, because this study used the cost analysis for a university hospital.

• Tribology and Lubricants
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• v.21 no.4
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• pp.159-164
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• 2005

An experimental study was conducted to evaluate characteristic variation of diluted engine oils in which contains diesel fuels and its tribological effects on engine components. In this study, diluted engine oils with $10\%,\;15\%,\;and\;20\%$ of initial fuel content rate have been used for measuring the viscosity reduction rate, blow-by gas increment rate, main gallery pressure reduction rate, and fuel content rate in engine oils. These parameters are strongly related to the tribological characteristics of key engine components. The kinematic viscosity of engine oils in which is contained by diesel fuels from $10\%\;to\;20\%$ in oils is decreasing to approximately $54\%$ of initial diluted fuel-oil volume ratios. The experimental results show that the distillated engine oil decrease the viscosity of engine oil and its oil film stiffness, and increase the wear rate of rubbing parts of engine components. Thus we recommend that the containing volume rate of fuels in engine oils should be restricted to $3\~4\%$ for a sophisticated Diesel engine and $5\~7\%$ for a standard one.

• Journal of the Korean Society of Safety
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• v.33 no.4
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• pp.21-29
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• 2018

In many companies handling flammable liquids, explosion-proof electrical equipment have been installed according to the Korean Industrial Standards (KS C IEC 60079-10-1). In these standards, hazardous area for explosive gas atmospheres has to be classified by the evaluation of the evaporation rate of flammable liquid leakage. The evaporation rate is an important factor to determine the zones classification and hazardous area distance. However, there is no systematic method or rule for the estimation of evaporation rate in these standards and the first principle equations of a evaporation rate are very difficult. Thus, it is really hard for industrial workplaces to employ these equations. Thus, this problem can trigger inaccurate results for evaluating evaporation range. In this study, empirical models for estimating an evaporation rate of flammable liquid have been developed to tackle this problem. Throughout the sensitivity analysis of the first principle equations, it can be found that main factors for the evaporation rate are wind speed and temperature and empirical models have to be nonlinear. Polynomial regression is employed to build empirical models. Methanol, benzene, para-xylene and toluene are selected as case studies to verify the accuracy of empirical models.

• International Journal of Highway Engineering
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• v.14 no.5
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• pp.179-188
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• 2012

PURPOSES: The aim of this study is to analyze overloading control effectiveness of enforcing overweighted vehicles using HS-WIM (High-Speed Weigh-in-Motion) at main lane of expressway. METHODS: To analyze the weight distribution statistically, HS-WIM system should has an appropriate weighing accuracy. Thus, the weighing accuracy of the two HS-WIM systems was estimated by applying European specifications and ASTM (American Standards for Testing and Materials) for WIM in this study. Based on the results of accuracy test, overweight enforcement system has been operated at main lanes of two expressway routes in order to provide weight informations of overweighted vehicle in real time for enforcement squad. To evaluate the overloading control effectiveness with enforcement, traffic volume and axle loads of trucks for two months at the right after beginning of the enforcement were compared with data set for same periods before the enforcement. RESULTS: As the results of weighing accuracy test, both WIM systems were accepted to the most precise type that can be useful to applicate not only statistical purpose but enforcing on overweight vehicles directly. After the enforcement, the rate of overweighted trucks that weighed over enforcement limits had been decreased by 27% compared with the rate before the enforcement. Especially, the rate of overweighted trucks that weighed over 48 tons had been decreased by 91%. On the other hand, in counterpoint to decrease of the overweighted vehicle, the rate of trucks that weighed under enforcement limits had been increased by 7%. CONCLUSIONS: From the results, it is quite clear that overloading has been controlled since the beginning of the enforcement.

• Journal of The Korean Society of Grassland and Forage Science
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• v.7 no.3
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• pp.122-127
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• 1987

This experiment was carried out to investigate the effect of shading degrees (0:full sunlight, 25, 50 and 75%) on the crop growth rate (CGR), net assimilation rate (NAR) and photosynthetic activity of grasses for obtaining the basic data on the development, management and utilization of pasture in the forest. For the test, different artificial shading houses were established and pasture species used in this study were orchardgrass, timothy, perennial ryegrass and ladino clover. The experiment was performed at Livestock Experiment Station, Suwon, in 1984-'85. The results obtained are summarized as follows. 1. The highest CGR was obtained at 0% (full sunlight) and 25% of shading, followed by 50 and 75% of shading degrees, in that order. CGR of orchardgrass and perennial ryegrass were higher than those of timothy and ladino clover. 2. NAR was significantly decreased as the shading degrees increased. The highest NAR was observed at perennial ryegrass plot. 3. The photosynthetic activity during summer season was the highest at 25% of shading, followed by 50, 0 and 75% of shading degrees. While, the photosynthetic activity during fall season was the highest at 25% of shading, followed by 50, 0 and 75% of shading degrees, in that order. Those of orchardgrass and perennial ryegrass were remarkably higher than that of timothy. 4. A significant positive correlation was obtained in the relationship between CGR and NAR of main grasses, regardless of pasture species and investigated date.