• Journal of the Korean Society of Safety
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• v.15 no.2
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• pp.70-77
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• 2000

For hazardous air pollutants(HAP) such as NO, $NO_2$ and $SO_2$ decomposition efficiency, power consumption, and applied voltage were investigated by SPCP(Surface induced discharge Plasma Chemical Processing) reactor to obtain optimum process variables and maximum decomposition efficiencies. Decomposition efficiency of HAP with various electric frequencies(5~50 kHz), flow rates(100~1,000 mL/min), initial concentrations(100~1,000 ppm) and additive($CH_4$) were measured and the products were analyzed with FT-IR. Experimental results showed that for the frequency of 10 kHz, the highest decomposition efficiency of 94.3 % for NO, 84.7 % for $NO_2$ and 99 % far $SO_2$ were observed at the power consumptions of 19.8, 20 and 19W, respectively, and that decomposition efficiency decreased with increasing frequency above 20 kHz. And decomposition efficiency per unit power were 5.21 %/W for $SO_2$, 4.76 %/W for NO and 4.24 %/W for $NO_2$ and the highest decomposition efficiency was observed with $SO_2$. Decomposition efficiency was increased with increasing residence times and with decreasing initial concentration of pollutants. When the additive of $CH_4$ was used, decomposition efficiency was increased with increasing $CH_4$ content, and NO, $NO_2$ and $SO_2$ were almost completely decomposed with the efficiency of 99 %, 98 % and 99 %, respectively and therefore $CH_4$ was a good additive material. The optimum power for the maximum decomposition efficiency were 7.5 W for $SO_2$, 9.5 W for NO and 15.5 W for $NO_2$, respectively. Optimum power with the maximum decomposition efficiency were 9.5 W at 1,000 ppm of NO, 7~8 W at 100~500 ppm of NO and 15.5 W at all concentration range of $NO_2$ and 11.5 W at 1,000 ppm, 4.9 W at 500 ppm, 3.7 W at 100~300 ppm of $SO_2$ and power efficiency was best in these case.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.640-647
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• 2018

Many harbor structures have been constructed, and some structures are now under construction in Korea, which is a peninsular state and a logistics hub in Northeast Asia. Expansions and extensions of existing harbors are also being planned to meet increasing natural disaster threats. Wave-dissipation concrete blocks are recycled or discarded based on the personal experience of engineers only, and there are no safety checks or criteria. To check the safety of used blocks, material evaluations were done by visual inspection of blocks on the ground and under water and from 20 non-destructive measurements of the rebound hardness test and 3 concrete core samples. Wave-dissipation blocks are sometimes fully or partially damaged in the process of transferring and mounting them or during construction. Therefore, a safety check is essential for recycling blocks with an evaluation of materials while considering the construction phases. To do this, a block was modeled with a 3D finite element method using ADINA, and impact analyses were done according to the transfer, mounting, and construction phases. From the results of the impact analyses and material evaluation, the safety checks and reasonable evaluation of used blocks were examined, and detailed construction methods are proposed. The methods are expected to maximize the reuse of used wave-dissipation blocks from an economical point of view.

• Journal of the Korean Institute of Gas
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• v.7 no.1 s.18
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• pp.24-27
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• 2003

In this paper it was investigated 15 heaters of CDU plant heater, NCC plant heater, CO plant heater, Aromatic plant heater and so on while running in our country. It was also analysed the standard of operation procedure, the action in alarm, the interlock system, the operating situation of the interlock by-pass and major accident about the heater and so on. This paper presents the installation of the on-line monitoring, the additional installation of the local pressure gauge and temperature gauge, the check in starting operation,'the management of the interlock by-pass, the change of manufacturer causing the disorder of instrument sensor, the management method of DCS alarm for methods of the interlock prevention and facilities improvement. It was few information about the heater interlock in the inside and outside of the country We mainly have studied with reflecting the opinion of the operator and manager on site, the sheet of process trouble and operation procedure and so on. we think that the accident relating to the interlock will significantly reduce if the companies apply the conclusion of this study(i.e. methods of the interlock prevention and facilities improvement).

• Clean Technology
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• v.20 no.4
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• pp.398-405
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• 2014

In the treatment of spent high energetic materials, the issues such as environmental pollution, safety as well as working capacity should be carefully considered and well examined. In this regard, incineration has been recommended as one of the most promising processes for the disposal of such explosives. Due to the fact that high energetic materials encompass various types and their different characteristics, the technology development dealing with various materials is not an easy task. In this study, rigorous modeling and dynamic simulation was carried out to predict dynamic physico-chemical phenomena for research department explosive (RDX). Plug flow reactor was employed to describe the incinerator with 263 elementary reactions and 43 chemical species. Simulation results showed that safe operations can be achieved mainly by controlling the reactor temperature. At 1,200 K, only thermal decomposition (combustion) occurred, whereas increasing temperature to 1,300 K, caused the reaction rates to increase drastically, which led to ignition. The temperature further increased to 3,000 K which was the maximum temperature recorded for the entire process. Case studies for different operating temperatures were also executed and it was concluded that the modeling approach and simulation results will serve as a basis for the effective design and operation of RDX incinerator.

• BMB Reports
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• v.36 no.1
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• pp.43-48
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• 2003

Understanding the process of carcinogenesis will involve both the accumulation of many scientific facts derived from molecular, biochemical, cellular, physiological, whole animal experiments and epidemiological studies, as well as from conceptual understanding as to how to order and integrate those facts. From decades of cancer research, a number of the "hallmarks of cancer" have been identified, as well as their attendant concepts, including oncogenes, tumor suppressor genes, cell cycle biochemistry, hypotheses of metastasis, angiogenesis, etc. While all these "hallmarks" are well known, two important concepts, with their associated scientific observations, have been generally ignored by many in the cancer research field. The objective of the short review is to highlight the concept of the role of human adult pluri-potent stem cells as "target cells" for the carcinogenic process and the concept of the role of gap junctional intercellular communication in the multi-stage, multi-mechanism process of carcinogenesis. With these two concepts, an attempt has been made to integrate the other well-known concepts, such as the multi-stage, multi-mechanisn or the "initiation/promotion/progression" hypothesis; the stem cell theory of carcinogenesis; the oncogene/tumor suppression theory and the mutation/epigenetic theories of carcinogenesis. This new "integrative" theory tries to explain the well-known "hallmarks" of cancers, including the observation that cancer cells lack either heterologous or homologous gap junctional intercellular communication whereas normal human adult stem cells do not have expressed or functional gap junctional intercellular communication. On the other hand, their normal differentiated, non-stem cell derivatives do express connexins and express gap junctional intercellular communication during their differentiation. Examination of the roles of chemical tumor promoters, oncogenes, connexin knock-out mice and roles of genetically-engineered tumor and normal cells with connexin and anti-sense connexin genes, respectively, seems to provide evidence which is consistent with the roles of both stem cells and gap junctional communication playing a major role in carcinogenesis. The integrative hypothesis provides new strategies for chemoprevention and chemotherapy which focuses on modulating connexin gene expression or gap junctional intercellular communication in the premalignant and malignant cells, respectively.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.5
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• pp.249-254
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• 2016

In this study, we investigated the main characteristics of off-gas generated from melting process and off-gas treatment system operation example to provide some primary data for commercial vitrification facility design. The purpose of vitrification facility operation is to treat hazardous materials in the radioactive wastes and harmful off-gas containing a variety of chemical species generated in the glass melting process. Constructing and operating vitrification facility essentially need to be licensed through safety analysis; it is very important to treat radionuclide and hazardous materials below the legal environment emissions regulation level. We must accurately understand the characteristics of off-gas and apply an appropriate off-gas treatment process accordingly. Thus, to design the appropriate off-gas treatment there must be a wide range of elements taken into account such as characteristics of waste and melter, regulation guidance of off-gas, characteristics of generated off-gas and off-gas treatment system performance assessment.

• Proceedings of KOSOMES biannual meeting
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• 2006.11a
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• pp.169-174
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• 2006

A distinctive difference of hydrocarbon in crude oil and petroleum products exists. Depending on the origin where it comes from, crude oil shows its own unique pattern which is different from petroleum products containing characteristics according to their operating process and production period. A process of mixing behavior in a tank containing residual amounts of oil draws its own pattern when analysis is conducted. The analytical process described above is named oil fingerprint method. This study investigates an effectiveness of the method for comparing data sets produced by conventional gas chromatography with mass spectrometer (GC/MS) and comprehensive two-dimensional gas chromatography (GC X GC) which is known as powerful new technology for chemical analysis.

• Fire Science and Engineering
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• v.28 no.6
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• pp.108-113
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• 2014

The combined process of Sliding Arc Plasma and corona dielectric barrier discharge process (CDBD) was used to efficiently improve harmful substance, which convert into OH radicals which have strong oxidation potential, and so have deodorization and sterilizing effects, by generating specific radicals and anion and then reacting with the moisture contained in harmful substance. As a result of experiment, even if the size of SAP reactor is reduced from 80 A to 50 A, there is no much change and therefore it is judged the size of reactor may be minimized. And it was confirmed that after the anion and ozone generated from CDBD rector react with harmful substance, a anion was reduced from 510,000 ppb to 470 ppb and ozone from 98 ppb to 22 ppb. It was also judged the stability and durability of plasma producer are excellent. Accordingly, it is considered the harmful substances which exist in indoor air quality will be efficiently improved and removed by using further plasma combined process through this study.

• Membrane Journal
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• v.21 no.2
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• pp.118-126
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• 2011

A method of light pre-irradiation, one of methods modifying hydrophobic surface to hydrophilic surface in a membrane, was proposed to overcome the drawback of previous methods such as blending, chemical treatment and post-irradiation, Process of membrane preparation in the study was comprised of 4 parts as follows: firstly process of precursor preparation to introduce hydrophilic nature under atmosphere and aqueous vapor by irradiating electron beam (EB), secondly process of dope solution preparation to cast on non-woven fabrics, thirdly process of casting to prepare membrane and finally process of coagulation in non-solvent to form porous structure. The merit of this method might show simple process as well as homogenous modification compared to previous methods. To carry it out, precursor was prepared by irradiating EB to powder PVDF at 75~125 K Gray dose. Precursor prepared was analyzed by FTIR, EDS and DSC to confirm the introduction of hydrophilic function and its mechanism. From their results, it was inferred I conformed that hydrophilic function was hydroxy1 and it was introduced by dehydrozenation. Hydrophilicity of membranes prepared was evaluated by contact angle (pristine PVDF : $62^{\circ}$, 125 K Gray-PVDF$13^{\circ}$). Porosity was evaluated by mercury intrusion method, simultaneously morpholoy and surface pore size were observed by SEM phothographs. The result showed the trend that more dose of EB led to smaller pore size and to lower porosity (pristine PVDF : 82%, 125 K Gray-PVDF : 63%). Trend of water permeability was similar to result above (pristine PVDF : 892 LMH, 125 K Gray-PVDF : 355 LMH).

• Korean Chemical Engineering Research
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• v.44 no.2
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• pp.216-226
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• 2006

Total trihalomethanes (THMs), dichloroacetic acid (DCAA) and trichloroacetic acid (TCAA) that are the major disinfection byproducts (DBPs) are monitored continuously in drinking water in Seoul. Study on characteristics of DBPs is crucial to judge the safety of drinking water in Seoul. Analysis of THMs, haloacetonitriles (HANs), chloral hydrate (CH), and haloacetic acids (HAAs) was carried out in several distribution systems from January 2002 to December 2004. The concentration of THMs was 0.015 mg/L in purified water, 0.019 mg/L in tapwater by direct service, and 0.023 mg/L in tapwater through watertank, respectively. It might be due to the increased contact time with chlorine by a process of the distribution system. And the other DBPs show a tendency to increase in its concentration by a process of the distribution system. Also, in summer, the concentration of DBPs was higher than in spring and winter. It might be due to the higher temperature of water in summer. In all cases, the quantities of detected DBPs were 4-6 times lower than those of regulation limits of drinking water in Seoul. In view of these results, the tapwater in Seoul is good to drink it all the times.