• Journal of the Korea Institute of Building Construction
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• v.17 no.1
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• pp.23-30
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• 2017

The aim of the research is to suggest an economical and sustainable method of reducing pH of recycled aggregate as an embanking and a covering materials. Because of the unhydrated cement based materials on the surface of the recycled aggregate, it causes a severe problem on environment with leaked high alkali water from embankment and covering by using recycled aggregate. In this research, to reduce the pH of recycled aggregate, regarding the recycled fine aggregate, eight different methods were tested and analyzed with three different categorized: natural treatment, artificial treatment, and chemical treatment. From the results of experiment, it was considered that the most efficient method of reducing pH of recycled aggregate was the chemical treatment using acid such as $CO_2$ acceleration or monoammonium phosphate (MAP), and diammonium phosphate (DAP). Especially, using MAP and DAP, fertilizers, is the most efficient method of reducing pH with its time duration and performance.

• Animal cells and systems
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• v.1 no.2
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• pp.337-340
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• 1997

The purpose of this study is to evaluate whether water soluble chitosan, a natural nontoxic chelator, can reduce fetal contamination of radiostrontium in pregnant mice. Various forms of water soluble chitosans (10% or 1% powder, or 1% solution) were given to pregnant mice before or after contamination of 0.005 uCi/B.W(g) Sr-85. Transplacental transfer of Sr-85 to fetus was $6.8{\pm}2.7%$ of injected dose, when Sr-85 was administered at the 20th day of pregnancy. Fetal radioactivity was significantly reduced when mother mice were treated with water soluble chitosan before contamination of Sr-85. Water soluble chitosans of 10% or 1% powder, or 1% solution significantly reduced fetal retention of Sr-85 to $2.3{\pm}0.7%$, $2.7{\pm}0.8%$, and $2.0{\pm}0.9%$, respectively. However, fetal contamination was not reduced, when water soluble chitosans of 10% or 1% powder, or 1% solution were administered after maternal contamination of Sr-85. From these data we can conclude that water soluble chitosan could reduce fetal contamination of radiostrontium in pregnant mice, when given before the pregnant mice were exposed to radiostrontium.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.3
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• pp.1-10
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• 1998

In this paper, we investigated the improvement of characteristics of knock, emission and fuel consumption rate by optimizing the location and size of water transfer holes in cylinder head gasket without change of engine water jacket design itself. The cooling system was modified in the direction of reducing the metal temperature in the head and increasing the metal temperature in the block. The optimization of water transfer holes in cylinder head gasket was obtained by "flow visualization test". The water transfer holes were concentrated in front side of the engine in order to reduce thermal boundary layer in the water jacket of No. 2 and No. 3 combustion changer in the cylinder head, which would have a large knock intensity, and increase thermal boundary layer in the water jacket of the cylinder block. When the modified coolant flow pattern was applied as proposed in this paper, the knock characteristic was improved. The spark timing was advanced up to 2$^{\circ}$ in low and middle speed range at a full load. In addition, HC emission at MBT was reduced by 5.2%, and the fuel consumption rate was decreased up to 1% in the driving condition of 2400 rpm and 250 KPa. However, since this coolant flow pattern mentioned in this paper might deteriorate the performance of vehicle cooling system due to the coolant flow rate reduction, a properly optimized point should be obtained. obtained.

• Journal of Korean Society on Water Environment
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• v.26 no.6
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• pp.1040-1048
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• 2010

An infiltration storage can be installed as a method of reducing runoff from catchment and increasing stream flow during the dry period by recharging groundwater. However, there is no proper model and method that can be used to design storage capacity of an infiltration storage in Korea. The purpose of the study is to evaluate capacities of infiltration storages planned on Jeju-do in Korea by modifying Storm Water Management Model (SWMM). The basic equations for the infiltration storage are same as those of the infiltration trench used in MIDUSS. Infiltration rates of the infiltration storages were first measured by double ring infiltrometers, and then the modified model was applied to evaluate adequacy for the capacities of three infiltration storages planned on Jeju-do in Korea. The application results show that the two infiltration storages with higher infiltration rates have adequate capacities to infiltrate the total water inflow to the storages. However, the other infiltration storage with lower infiltration rates has not sufficient capacity to infiltrate the total water inflow to the storage and release occurs to the downstream region. The simulation model and method applied can be used for capacity evaluation of future infiltration storages on highly pervious areas in Jeju-do.

• Environmental and Resource Economics Review
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• v.10 no.2
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• pp.235-257
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• 2001

As in other Asian countries, the Korean government provides direct subsidies to endeavors that are potentially harmful to the environment. The water sector is one of the main recipients of these subsidies. The total amount of estimated direct fiscal subsidies equals 2.200 trillion won; however, the comprehensive cost of the subsidies is estimated to be much greater because environmental and social costs were not considered in the initial calculation. Most of the fiscal direct subsidies in the water sector are subsidized to urban water areas. The percentage of fiscal direct subsidies in the urban water sector to the total fiscal direct subsidies is 79.68%, while the percentage of fiscal direct subsidies in the industrial water sector is only 4.92%. Since the ratio of fiscal direct subsidies in the industrial water sector is quite small, the negative impact of removing fiscal direct subsidies for the industrial sector may be trivial. If the Korean government cuts dowm the VAT or income tax rate while reducing several types of subsidies, it will be able to achieve a double dividend effect both on the economy and the environment.

• The Korean Journal of Community Living Science
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• v.26 no.2
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• pp.351-360
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• 2015

The study examines the effects of the Cnidium officinale Makino water extract on hyperlipidemia. For this, three levels (low, moderate, and high) of the Cnidium officinale Makino water extract were supplemented to six-week-old male sprague Dawley rats for five weeks. According to the results, serum total lipid, triglyceride, total cholesterol, and LDL cholesterol levels showed significant decreases (p<0.05) in the group with the Cnidium officinale Makino water extract. The serum total lipid level decreased by 8~22%; the triglyceride level, by 13~25%; the total cholesterol level, by 6~23%; and the LDL cholesterol level, by 14~25%. Total cholesterol and triglyceride levels in the liver were significantly lower in the group with the Cnidium officinale Makino water extract than in the control group (p<0.05), and fecal total cholesterol and triglyceride levels were significantly higher in the group with the Cnidium officinalle Makino water extract. These results suggest that the Cnidium officinale Makino water extract in the hypercholesterol diet may reduce hyperlipidemia, a major cause of cardiovascular disease, by reducing serum cholesterol and triglyceride level in the liver through the facilitation of their excretion by feces.

• Journal of Mechanical Science and Technology
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• v.20 no.10
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• pp.1576-1589
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• 2006

Most of surface water ways in Egypt suffer from the infestation of aquatic weeds especially submerged ones which cause lots of problems for the open channels and the water structures such as increasing water losses, obstructing the water flow, and reducing the efficiency of the water structures. Accurate simulation of the water flow behavior in such channels is very essential for water distribution decision makers. Artificial Neural Network (ANN) has been widely utilized in the past ten years in civil engineering applications for the simulation and prediction of the different physical phenomena and has proven its capabilities in the different fields. The present study aims towards introducing the use of ANN technique to model and predict the impact of the existence of submerged aquatic weeds on the hydraulic performance of open channels. Specifically the current paper investigates utilizing the ANN technique in developing a simulation and prediction model for the flow behavior in an open channel experiment that simulates the existence of submerged weeds as branched flexible elements. This experiment was considered as an example for implementing the same methodology and technique in a real open channel system. The results of current manuscript showed that ANN technique was very successful in simulating the flow behavior of the pre-mentioned open channel experiment with the existence of the submerged weeds. In addition, the developed ANN models were capable of predicting the open channel flow behavior in all the submerged weeds' cases that were considered in the ANN development process.

• Journal of Korean Society of Rural Planning
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• v.25 no.4
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• pp.35-45
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• 2019

Korean agriculture experienced rapid changes in its production structure to respond fluctuations on external conditions, and these changes have increased the dependence between agricultural resources and negative environmental externalities from agricultural production. As a tool for managing agricultural resources and reducing negative environmental effects from agricultural production, this study employs water-energy-food nexus for integrated resource management. To show the necessity of an integrated approach, this study evaluated three policy scenarios including changes in capital interest, water capacity, and energy cost. The results show that three scenarios have unintended consequences for farmers' incomes and their use of resources. Also the unintended consequences of government policies also affected farms' vulnerability to environmental changes. In particular, the expansion of financing for the establishment of non-circulating water curtain facilities did not have a significant effect on the crop switching of farms. In addition, increasing the amount of available water through the aquifer recharge project leads to the installation of non-circulating water curtain facilities in zucchini farm. It raises dependence on groundwater in agricultural production, thereby increasing farmers' vulnerability to groundwater shortages. These results imply that the agricultural sector needs to consider the interrelationship between agricultural resources when designing or evaluating policies.

• Journal of Microbiology
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• v.37 no.4
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• pp.206-212
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• 1999

In order to isolate a Fe(III)-reducer from the natural environment, soil samples were collected from various patty fields and enriched with ferric citrate as a source of Fe(III) under anaerobic condition. Since the enrichment culture was serially performed, the Fe(III)-reduction activity was serially diluted and cultivated on an agar plate containing lactate and ferric citrate in an anaerobic glove box. A Gram negative, motile, rod-shaped and facultative anaerobic Fe(III)-reducer was isolated based on its highest Fe(III)-reduction activity, Bacterial growth was coupled with oxidation of lactate to Fe(III)-reduction, but the isolate fermented pyruvate without Fe(III), The isolate reduced an insoluble ferric iron (FeOOH) as well as a soluble ferric iron (ferric citrate). Using the BBL crystal enteric/non-fermentor identification kit and 16S rDNA sequence analysis, the isolate was identified as Shewanella putrefaciens IR-1.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.2
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• pp.123-129
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• 2018

The aim of the research is providing a fundamental idea of reducing viscosity of cement based materials by replacing powder based material. With developing concrete technology, high performance concrete with high solid volume fraction has been used widely. Under the conditions of the high solid volume fraction due to the low w/c and replacement of SCMs, decreased fluidity is one of the critical problem, and thus plasticizer has been used to improve fluidity of the mixture. However, in rheological aspect, the fluidity of cement based materials can be defined with yield stress and viscosity, and using plasticizer only decreases yield stress without least controlling on viscosity. Therefore, based on the idea of Krieger-Dougherty model, a feasibility of wasted limestone powder from cement manufacturing process was used to decrease the viscosity of the mixture by replacing cement powder. According to a series of experiment, by replacing wasted limestone powder solely, there was a possibility of reducing viscosity was observed. Thus, in this research scope, it is considered to contribute on providing a fundamental idea of reducing viscosity with powder replacement and it is expected to contribute on further research using various conditions of replacing powders for reducing viscosity of cementitious materials.