• Applied Chemistry for Engineering
• /
• v.16 no.4
• /
• pp.556-562
• /
• 2005

This study was performed to evaluate effects of pH and heavy metals on soil pollution in 167 sites of Gangwon-do. The overall pH range of soils was 4.3~8.4 The average soil pollution of Cd was 0.089 mg/kg (0.000~3.493 mg/kg), Cu 3.093 mg/kg (0.078~60.263 mg/kg), Pb 4.74 mg/kg (0.01~38.08 mg/kg), Hg 0.054 mg/kg (0.002~1.050 mg/kg), and As 0.971 mg/kg (0.031~77.051 mg/kg), but $Cr^{6+}$ was not detected in these soils. The average concentration of heavy metals in these soils was acceptable under the preliminary standard of soil preservation acts in Korea.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.15 no.5
• /
• pp.209-217
• /
• 2011

In recent days, while taller and more massive structures such as huge bridges and super skyscrapers have been welcomed, the structural stabilization in design and construction have been gradually limited due to the major weakness of current concrete which is relatively heavier when compared with its strength. To improve the weakness of the current concrete, The lightweight concrete with light weight and high strength should be used; however, not many researchers in Korea have studied on the lightweight concrete. Generally, artificial lightweight aggregate produced through high-temperature-plasticization has a possibility of its body-expansion with many bubbles. Therefore, depending on the size of aggregate, the effects of bubbles on the specific weight and strength of the lightweight concrete should be studied. In this study, considering grain-size, the mix design of the artificial lightweight aggregate produced through the high-temperature-plasticization and the body-expansion of waste and clay from the fire power plant in Korea was conducted. The experiment to analyze the variation in specific weight and strength of the lightweight concrete was followed. From these experiments, the optimized grain-size ratio of the artificial lightweight aggregate for the enhancement of high-strength from the lightweight concrete was revealed.

• Journal of Hydrogen and New Energy
• /
• v.18 no.1
• /
• pp.12-25
• /
• 2007

Numerical simulation of the natural gas steam reforming process for on-site hydrogen production in a $H_2$ fueling station was conducted on the basis of process material and heat balances. The effects of reforming parameters on the process efficiency of hydrogen production were investigated, and set-point values of each of the parameters to minimize the sizes of unit process equipments and to secure a stable operability of the reforming process were suggested. S/C ratio of the reforming reactants was found to be a crucial parameter in the reforming process mostly governing both the hydrogen production efficiency and the stable operability of the process. The operation of the process was regarded to be stable if the feed water(WR) as a reforming reactant could evaporate completely to dry steam through HRSG. The optimum S/C ratio was 3.0 where the process efficiency of hydrogen production was maximized and the stable operability of the process was secured. The optimum feed rates of natural gas(NGR) and WR as reforming reactants and natural gas(NGB) as a burner fuel were also determined for the hydrogen production rate of $27\;Nm^3/h$.

• Herbal Formula Science
• /
• v.23 no.2
• /
• pp.235-243
• /
• 2015

Objectives : The object of this paper is to seek and provide evidences for the possibilities of substitutional use of Aquilariae Resinatum Lignum and Aucklandiae Radix for Moschus as an ingredient of Gongjin-dan by clarifying the similarities and differences among these herbs in the classic literatures. Methods : We have found out the features of Moschus, Aquilariae Resinatum Lignum and Aucklandiae Radix by searching Qi, Flavor and Effect of each herb in 『Shennongbencaojing』, 『Zhengleibencao』, 『Bencaogangmu』, 『Dongeuibogam』, 『Bencaobeiyao』, 『Euijongsonik』 and 『Bangyakhappyeon』. And we have compared and analyzed the fomula of Gongjin-dan and other prescriptions in 『Beijiqianjinyaofang』, 『Shengjizonglu』, 『Shiyidexiaofang』, 『Dongeuibogam』, 『Euijongsonik』, 『Euibanghwaltu』 and 『Bangyakhappyeon』. Results : We could find out the similarities and differences in Qi, Flavor and Effect among Moschus, Aquilariae Resinatum Lignum and Aucklandiae Radix. And we could also find the examples of substitutional use of Aquilariae Resinatum Lignum as an ingredient of Gongjin-dan by comparing the formula of Gongjin-dan in the classic literatures as above. And in the other prescription, Aucklandiae Radix was also used instead of Moschus. Conclusions : All of three herbs have pungent in Flavor and warm in Qi. And these herbs also have similar effects in dispersing invading pathogenic factors and smoothening the flow of Qi. And according to 『Bencaobeiyao』, 『Euijongsonik』 and 『Bangyakhappyeon』, Aquilariae Resinatum Lignum and Aucklandiae Radix direct and regulate the Qi in common. The substitutional use of Aquilariae Resinatum Lignum and Aucklandiae Radix instead of Moschus in Gonjin-dan seems to be related to 'the ascent of Water and descent of Fire' effect of Gongjin-dan.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.12 no.6
• /
• pp.60-65
• /
• 2004

Numerical simulations and experiments have been carried out to investigate the effect of fuel injection nozzles on the combustion and NOx formation processes in a medium-speed marine diesel engine. Spray visualization experiment was performed in the constant-volume high-pressure chamber to verify the numerical results on the spray characteristics such as spray angle and spray tip penetration. Time-resolved spray behaviors were captured by high-speed digital camera and analyzed to extract the information on the spray parameters. Spray and combustion phenomena were examined numerically using FIRE code. Wave breakup and Zeldovich models were adopted to describe the atomization characteristics and NOx formation processes. Numerical results were verified with experimental data such as cylinder pressure, heat release rate and NOx emission. Finally, the effects of fuel injection nozzles on the engine performance were investigated numerically to find the optimum nozzle parameters such as fuel injection angle, nozzle hole diameter and number of nozzle holes. From this study, the optimum fuel injection nozzle (nozzle hole diameter, 0.32 mm, number of nozzle holes, 8 and fuel injection angle, $148^{\circ}$) was selected to reduce both the fuel consumption and NOx emission. The reason for this selection could be explained from the highest fuel-air mixing in the early phase of injection due to the longest spray tip penetration and the highest heat release rate after $19^{\circ}$ ATDC due to the increased injection duration.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.18 no.1
• /
• pp.33-37
• /
• 2008

The effects of Cu and Sb on the microstructure and mechanical properties of Sn-Sb-Cu-Ni-Cd whitemetal were investigated. Any compound phase was not observed in the whitemetal with 0.05 wt% Cu, while as the Cu content was increased, star- or needle-like $Cu_6Sn_5$ phases were found. The tensile strength gradually increased with Cu up to 5 % and then remained almost constant with Cu content above 5 %, while the hardness continuously increased with Cu content because of the increased hard $Cu_6Sn_5$ phases. As the Sb content increased, SbSn cuboids were present as well as $Cu_6Sn_5$. The tensile steength and hardness continuously increased and the elongation decreased with Sb content.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.5
• /
• pp.106-113
• /
• 2010

If leakage current is neglected, it can become a cause for disasters such as electric shock and fire, therefore a continuous monitoring is necessary. However in most cases, because management of substations is performed by unmanned systems, or walk-around inspections, continuous monitor is difficult. So when an accident occurs and the cause is not immediately resolved causing the emergency generator's OCGR getting activated by the leakage current that in turn cut off the ACB, the emergency generator may stop working. To prevent such a problem, a real-time integrated monitoring system for monitoring the leakage current returning to the grounding wire of neutral point of the low voltage side of transformer is proposed. Therefore in this paper, the effects of flow of leakage current, which is caused by insulation degradation phenomena or insulation destroy phenomena, were identified by simulation. And through cases studies; the excellence of integrated monitoring system was verified.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2017.05a
• /
• pp.69-70
• /
• 2017

As the industry develops, the size of buildings and ships are getting bigger and more complicated. In such a complex space, emergency evacuation systems are required because of the possibility of casualties when an accident situation occurs. However, because present systems are composed of basic devices, such as alarms, emergency exit signs, and announcement regarding the situation and inform only the least information to evacuees, evacuees are not able to judge objectively. To solve these problems, various evacuation algorithms have been proposed. However, these studies aim to search evacuation routes based on specific risk factors or to model the effects of bottlenecks in evacuation situations. Therefore, there is a limit to apply to real systems. Therefore, we propose algorithms to search the optimal evacuation route considering various risk factors such as fire and bottleneck in evacuation situations and to be applicable in actual situation in this paper. Performance evaluation using computer simulations showed that the proposed scheme is effective.

• Elastomers and Composites
• /
• v.44 no.3
• /
• pp.299-307
• /
• 2009

The effects of reinforcing materials on durability and mechanical properties of V-rib belt were investigated. Cotton fiber and ZnO were used as a filler for CR, and cotton and aramid fiber were used for EPDM rubber compounds. These materials were prepared as a specimen and V-rib belt for heat resistant and mechanical test. High contents of ZnO give improved wear resistance, and higher contents of cotton fiber showed higher durability in high rotation speed but lower wear resistance for CR rubber compounds. Using the aramid and cotton fiber together in EPDM rubber compounds, thermal and wear resistance were improved simultaneously. The material containing EPDM matrix showed better durability and wear resistance than those of containing CR matrix comparing in the same cotton fiber contents.

• Journal of Digital Contents Society
• /
• v.19 no.2
• /
• pp.269-276
• /
• 2018

The purpose of the study is to verify whether literature therapy program for prevention of smartphone addiction is effective for adolescents. The subjects of this study were 150 students of J City, K middle school. After completing the program, they were conducted post-test for both the experimental and control groups. The study found that the program was effective in mitigating smartphone addiction but not in reducing the directed life problem. It was also found to be effective in reducing tolerance and loss of control and problems of withdrawal and emotional experience. The study suggests that institutional arrangements are needed for linking with related organizations in the region because it is difficult to effectively prevent the increasing problem of smartphone addiction unless an adolescents program for youth is linked to the school. Therefore, it is necessary to conduct parent education for prevention of smartphone addiction in computer curriculum of school subjects.