• Fire Science and Engineering
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• v.30 no.3
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• pp.55-61
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• 2016

In this study, to determine whether it is possible to apply Polyethylene (PE) compound pipe, which was developed to solve the problem caused by the corrosion of the fire protection piping currently in usein water based fire extinguishing systems, we performed an actual mockup fire test. Since no test standard was available related to the developed compound pipe, we compared and analyzed domestic and international technical materials and test standards and selected suitable fire test standards to evaluate the performance of the PE compound pipe. we applied two fire test standards to the PE compound pipe, viz. those for CPVC and metallic pipes, and conducted a total of 6 experiments to evaluate its performance. According to the results of the first and second fire tests based on the test standard for the CPVC pipe, neither the fitting nor the piping was damaged or deformed and no leakage was observed in the pressure test, which was performed for 5 minutes. For the fire test based on the metallic pipe test standard, a total of 4 experiments were conducted. The first two experiments were conducted to simulate the wet piping system. In the results of this fire test, neither leakage nor rupture was observed from the PE compound pipe and no damage was caused, such as the secession of the PE material. However, in the next two experiments, which simulated the dry system, the PE compound pipe suffered damage and rupture, including deformation before the fire fighting water was discharged. Therefore, we found that the piping performance of the PE compound pipe did not undergo any deterioration, including fusion, deformation, or damage, in the wet piping system simulated fire test.

• Journal of Surface Science and Engineering
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• v.49 no.6
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• pp.513-520
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• 2016

Many surface protection methods have been developed to apply to constructional steels which have been used under severe corrosive environments. One of these methods, hot dip galvanizing is being widely used to the numerous constructional steels such as a guard rail of high way, various types of structural steel for manufacturing ship and for some other industrial fields etc.. Recently, the cost of zinc is getting higher and higher, thus, it is considered that improvement of hot dip galvanizing process to reduce the cost of production should be developed possibly. In this study, additives such as acid cleaning solution, $NH_4OH$, $Al(OH)_3$ and $H_2O_2$ were added to flux solution, and omission of water washing treatment after acid cleaning was investigated with some types of flux solutions added with some additives mentioned above. The decrement of pH by adding the acid cleaning solution could be controlled due to neutralization reaction with addition of $NH_4OH$. The flux solution added with both $NH_4OH$ and $Al(OH)_3$ exhibited nearly the same color and pH value as those of orignal flux solution with no added, and the sample dipped to the flux solution which was added with additives mentioned above indicated a relatively good corrosion resistance compared to other samples. However, the flux solution added with $NH_4OH$, $Al(OH)_3$ and $H_2O_2$ exhibited a different color, sediment and a bad corrosion resistance. Consequently, it is considered that omission of water washing treatment may be able to perform by adding optimum additives to the original flux solution.

• Journal of the Korean Institute of Gas
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• v.20 no.4
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• pp.50-57
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• 2016

According to the urban gas business legislation, cathodic protection systems should be applied for buried steel gas pipelines to prevent corrosion. In advanced countries including United States, the criteria for Cathodic Protection Potential is at least -850mV with respect to a saturated copper/copper sulfate electrode(CSE) when the CP applied, and the IR drops must be considered for valid interpretation. However, the IR drop through the pipe to soil boundary has been neglected in Korea. According to KGS code, a reference electrode must be placed in proximity to gas pipelines possible when measuring the CP potential. In this study, we have installed several solid reference electrodes around the buried pipeline(1.2m depth), lower surface(0.5m depth), and the surface individually in order to measure the CP potentials through the each reference electrode and find out the IR drops according to the location of each reference electrode. We have found the IR drop is the greatest when measuring the CP potential through the electrode placed on the ground and the IR drop is the smallest through the electrode installed near pipeline. Therefore, we have suggested the solid reference electrode should be installed as close as possible to buried pipeline in order to measure the correct CP potential without IR drop. We have also suggested the amendment of CP criteria considering IR drop.

• Fire Science and Engineering
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• v.29 no.4
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• pp.61-66
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• 2015

PVC pipe has excellent corrosion resistance and chemical resistance and is broadly used. However there are no regulations regarding exposed piping material in buildings. There is growing concern about the vulnerability of piping to fires and generating toxic gas. Exposed piping should be made of incombustible materials to prevent spreading of toxic gas and to minimize damage to life and property in case of fire. Many big structures are being built, and concerns regarding damage by fire are continuously growing. In these circumstances, we should reinforce fire safety standards for buildings and heighten safety consciousness to become a well-developed country. For these reasons, we investigated the materials used for exposed piping and the standards of well-developed countries to enhance safety. We tried to figure out the alternatives by examining the actual conditions of each region's buildings. Based on the use of incombustible materials for exposed piping in each region, we tried to enhance the effectiveness for safety by suggesting revisions for related laws and regulations.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.sup3
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• pp.205-211
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• 2016

Excessive exposure to chemicals in the workplace can cause poisoning and various diseases. Thus, for the protection of labor, it is necessary to examine the exposure of people to chemicals and risks from these materials. The purpose of this study is to evaluate semi-quantitative health risks of exposure to harmful chemical agents in the context of carcinogenesis in a latex glove manufacturing industry. In this cross-sectional study, semi-quantitative risk assessment methods provided by the Department of Occupational Health of Singapore were used and index of LD50, carcinogenesis (ACGIH and IARC) and corrosion capacity were applied to calculate the hazard rate and the biggest index was placed as the basis of risk. To calculate the exposure rate, two exposure index methods and the actual level of exposure were employed. After identifying risks, group H (high) and E (very high) classified as high-risk were considered. Of the total of 271 only 39 (15%) were at a high risk level and 3% were very high (E). These risks only was relevant to 7 materials with only sulfuric acid placed in group E and 6 other materials in group H, including nitric acid (48.3%), chromic acid (6.9%), hydrochloric acid (10.3%), ammonia (3.4%), potassium hydroxide (20.7%) and chlorine (10.3%). Overall, the average hazard rate level was estimated to be 4 and average exposure rate to be 3.5. Health risks identified in this study showed that the manufacturing industry for latex gloves has a high level of risk because of carcinogens, acids and strong alkalisand dangerous drugs. Also according to the average level of risk impact, it is better that the safety design strategy for latex gloves production industry be placed on the agenda.

• Journal of Radiation Protection and Research
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• v.35 no.1
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• pp.12-20
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• 2010

In a primary system at nuclear power plants (NPPs), various radionuclides including fission products and corrosion products are generated due to the complex water conditions. Particularly, $^3H,\;^{14}C,\;^{58}Co,\;^{60}Co,\;^{137}Cs,\;and^{131}I$ are important radionuclides in respect of dose assessment for radiation workers and management of radioactive effluents. In this paper, the dominant contributors of radiation exposure for radiation workers and the member of public adjacent to NPPs were reviewed and the process of dose assessment attributable to those contributors were introduced. Furthermore, the analysis for some examples of radiation exposure to radiation workers and the public during the NPP operation was carried out. This analysis included the notable precedents of internal radiation exposure and contamination of demineralized water occurred in Korean NPPs. Particularly, the potential issue about the dose assessment of tritium and carbon-14 was also reviewed in this paper.

• Journal of the Korean Society for Railway
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• v.10 no.1 s.38
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• pp.57-66
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• 2007

1974. 8. 15 SeoulMetro, beginning with the first electric railway established at six cities, so it is managing mass transportation of traffic. Especially, in case of seoul, It is managing that from one to eight lines, 286.9km, 265 stations have installed and now it is carrying about 5.5million of passengers everyday, and 2,000million passengers a year. So accident is increasing from the station every year. For this measure, SeoulMetro prepares safety fence for passengers crash but, as suicides or people who watch the accident took place, for at the bottom of passengers crash protection, PSD installing is needed. Even though, PSD is managing ATO section but, in controlling SeoulMetro, one to four lines sections are (ATS, ATC)section. Between as ATS, ATC section, ATO section, subway gate and PSD must have opened and crossed always at the time. And the interlock control corrosion protection gate, managing skills with installation, method, using in history, apply to 10rail cars one train sets, and maximum applying 2224% sections of passengers congested that consideration is to be needed. So 2004, SeoulMetro improved technology and basie design of PSD at ATS section. Based on this, from 2005.4 to 2006.6, using subway 2lines per 12stations set the model installation(full type 11stations, half type 1station) After installing in case of success, it is going about to suggest that effective analysis and hereafter subject.

• Journal of the Korea Institute of Building Construction
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• v.5 no.3 s.17
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• pp.83-90
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• 2005

Was used at step space-time mainly after VE technique sponsors in domestic in the 1960s but have been expanded to design step recently. Possibility of value elevation or cost reduction must choose member that is effectively for active and effective application of VE technique. In this study, when enforce design VE examining for weight decision corrosion protection been using in weight grant composition estimation technique, target choice process wishes to suggest formality and method that can be achieved effectively Main conclusion of this study sorts valuation items step by step for weight appropriation of valuation basis and give point on article of high position point after expert which employer is included estimates article by low rank step and this presented high position method that do union item by item and establishes by item weight. Did these techniques for giving weights so that importance for weight appropriation developed estimation program, and data save of target estimation standard and target estimation standard is possible using straight sit.

• Journal of the Korean Ceramic Society
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• v.51 no.5
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• pp.481-486
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• 2014

Environmental barrier coatings (EBCs) are used to protect SiC-based ceramics or composites from oxidation and corrosion due to reaction with oxygen and water vapour at high temperatures above $1000^{\circ}C$. Mullite ceramics have been studied for environmental barrier coatings for Si-based ceramics. More recently, rare earth silicate ceramics have been identified as more water vapour-resistant materials than mullite for environmental barrier coatings. In this study, we fabricate mullite and yttrium silicate ceramics by an atmospheric plasma spray coating method using spherical granules fabricated by spray drying. As a result, EBCs with thicknesses in the range of $200-300{\mu}m$ are successfully fabricated without any macroscopic cracks or interfacial delamination. Phase and microstructure analysis are conducted, and the basic mechanical properties, such as hardness and indentation load-displacement curves are evaluated.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.149-155
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• 2005

Was used at step space-time mainly after VE technique sponsors in domestic in the 1960s but have been expanded to design step recently. Possibility of value elevation or cost reduction must choose member that is effectively for active and effective application of VE technique. In this study, when enforce design VE examining for weight decision corrosion protection been using in weight grant composition estimation technique, target choice process wishes to suggest formality and method that can be achieved effectively. Main conclusion of this study sorts valuation items step by step for weight appropriation of valuation basis and give point on article of high position point after expert which employer is included estimates article by low rank step and this presented high position method that do union itembyitemandestablishesbyitemweight. Did these techniques for giving weights so that importance for weight appropriation developed estimation program, and data save of target estimation standard and target estimation standard is possible using straight sit.