• Environmental Engineering Research
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• v.25 no.4
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• pp.561-570
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• 2020

In the present study, dye decolorizing bacteria were isolated from water and soil samples, collected from textile industries in Jodhpur province, India. Two bacterial species namely, Bacillus pumilis and Paenibacillus thiaminolyticus were screened and identified based on biochemical characterization. The degradation efficiency of these two microorganisms was compared through optimization of pH, incubation time, initial dye concentration and inoculum size. B. pumilis and P. thiominolyticus were able to degrade 61% and 67% Red HE3B, 81% and 75% Orange F2R, 49.7% and 44.2% Yellow ME4GL and 61.6% and 59.5% Blue RC CT dyes of 800mg/l concentration respectively. The optimum pH and time were found to be 8 within 24 hours. The FT-IR analysis confirmed that microorganisms were able to degrade toxic azo dyes into a non-toxic product as proved through structural modifications to analyze chemical functions in materials by detecting the vibrations that characterize chemical bonds. It is based on the absorption of infrared radiation by the microbial product. Therefore, Bacillus pumilis and Paenibacillus thiaminolyticus are a promising tool for decolorization of dyes due to its potential to effectively decolorize higher azo dye concentrations (10-800 mg/L) and can be exploited for bioremediation.

• The Korean Journal of Food And Nutrition
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• v.33 no.3
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• pp.257-265
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• 2020

This study investigated the volatile flavor composition of essential oils from Solidago virga-aurea var. asiatica Nakai with different harvesting area. The essential oils obtained by the hydrodistillation extraction method from the aerial parts of the plants were analyzed by gas chromatography (GC) and GC-mass spectrometry (GC-MS). Ninety-five (91.61%) volatile flavor compounds were identified in the essential oils from the S. virga-aurea var. asiatica Nakai harvested in Koheung, Jeolanamdo. The major compounds were hexadecanoic acid (29.22%), 7-hexyl eicosane (9.12%), spathulenol (7.701%), 3,8-dimethyl decane (6.48%), caryophyllene oxide (4.52%) and α-copaene (4.23%). Fifty-seven (97.43%) volatile flavor compounds were identified in the essential oils from the S. virga-aurea var. asiatica Nakai harvested in Seoguipo, Jejudo. The major compounds were 2-carene (40.95%), α-copaene (10.77%), α-muurolene (5.81%), and spathulenol (3.11%). The chemical composition of the essential oils was significantly different in quality and quantity with the different harvesting area. The quantitative variations of hexadecanoic acid, 7-hexyl eicosane, spathulenol, 3,8-dimethyl decane, caryophyllene oxide, 2-carene, and α-copaene according to different harvesting area can serve as a quality index of the S. virga-aurea var. asiatica Nakai essential oils in food industries.

• Journal of the Korean Society of Safety
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• v.20 no.1 s.69
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• pp.94-100
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• 2005

The plasma, ionized gas state, is generally composed as the 4th state in the universe. Generating the plasma artificially has been studied by spending energy and it has been applied so much in human's life. There are several merits to modify the surface of polymer using plasma. Above all, plasma maintains the properties of polymer itself, but changes the properly of polymer surface only. Also, it is the environmentally fraternized because there are no waste processing from organic solvent. Furthermore, it is possible that continuous automated-processing in case of high-pressure plasma. Therefore, we have tried the reforming of surface to rise the adhesive strength between the material of polymer, and have experimented rising the adhesive strength through peel strength by virtue of processing time and using gas, of course, confirmed the change of polymer surface through measuring the contact angle analysis and scanning electron microscopy(SEM).

• Bulletin of the Korean Chemical Society
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• v.28 no.8
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• pp.1383-1388
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• 2007

Recently, the semiconductor and display industries have tried to reduce the emissions of perfluorocompounds (PFCs) from the globally environmental regulation. Total amount of PFC emission can be calculated from the flow rate and the partial pressures of PFCs. For the precise measurement of PFC emission amount, the mass flow controlled helium gas was continuously injected into the equipment of which scrubber efficiency is being measured. The partial pressures of PFCs and helium were accurately measured using a mass spectrometer in each sample extracted from inlet and outlet of the scrubber system. The flow rates are calculated from the partial pressures of helium and also, PFC destruction and removal efficiency (DRE) of the scrubber is calculated from the partial pressure of PFC and the flow rate. Under this method, the relative expanded uncertainties of the flow rate and the partial pressures of PFCs are ± 2% (k = 2) in case the concentrations of NF3 and SF6 are as low as 100 μmol/mol.

• Corrosion Science and Technology
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• v.7 no.3
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• pp.145-151
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• 2008

Material degradation such as high temperature oxidation of metallic material is a severe problem in energy generation systems or manufacturing industries. The metallic materials are oxidized to form oxide films in high temperature environments. The oxide films act as diffusion barriers of oxygen and metal ions and thereafter decrease oxidation rates of metals. The metal oxidation is, however, accelerated by mechanical fracture and spalling of the oxide films caused by thermal stresses by repetition of temperature change, vibration and by the impact of solid particles. It is therefore very important to investigate mechanical properties and adhesion of oxide films in high temperature environments, as well as the properties in a room temperature environment. The oxidation tests were conducted for Ni and Ni-Co alloy under high temperature corrosive environments. The hardness distributions against the indentation depth from the top surface were examined at room temperature. Dynamic indentation tests were performed on Ni oxide films formed on Ni surfaces at room and high temperature to observe fractures or cracks generated around impact craters. As a result, it was found that the mechanical property as hardness of the oxide films were different between Ni and Ni-Co alloy, and between room and high temperatures, and that the adhesion of Ni oxide films was relatively stronger than that of Co oxide films.

• Clean Technology
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• v.5 no.2
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• pp.1-12
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• 1999

Cleaning Processes are widely employed in the manufacturing processes of many industries and various environmental contaminants are generated during their operation. Thus, as the environmental and safety regulations are getting severer at home and abroad, it is indispensable that the existing cleaning agents which are causing environmental and safety problems should be replaced by the more environmentally-friendly alternative ones. In order to select alternative cleaning agents, it is necessary that their cleaning power is equivalent to or better than that of existing cleaning agents. However, the evaluation methods of cleaning power of industrial cleaning agents have not been established for comparison of cleanliness. In this study, various kinds of evaluation methods of cleanliness which can be utilized in the laboratory or in the industrial field are examined and their field application cases are reviewed and analyzed.

• Macromolecular Research
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• v.17 no.2
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• pp.121-127
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• 2009

The cure kinetics of the epoxy-layered, silicate nanocomposites were studied by differential scanning calorimetry under isothermal and dynamic conditions. The materials used in this study were o-cresol novolac epoxy resin and phenol novolac hardener, with organically modified layered silicates. Various kinetic parameters, including the reaction order, activation energy, and kinetic rate constants, were investigated, and the storage stability of the epoxy-layered silicate nanocomposites was measured. To synthesize the epoxy-layered silicate nanocomposites, the phenolic hardener underwent pre-intercalation by layered silicate. From the cure kinetics analyses, the organically modified layered silicate decreased the activation energy during cure reaction in the epoxy/phenolic hardener system. In addition, the storage stability of the nanocomposite with the pre-intercalated phenolic hardener was significantly increased compared to that of the nanocomposite with direct mixing of epoxy, phenolic hardener, and layered silicate. This was due to the protective effect of the reaction between onium ions and epoxide groups.

• Membrane Journal
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• v.26 no.2
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• pp.152-158
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• 2016

The Chlor-alkali (CA) membrane cell is a major electrolysis system to produce valued chemicals such as chlorine gas and sodium hydroxide. The CA membrane process has been attracted in the industries, since it has relatively low energy consumption when compared with other CA processes. The key component in CA process is perfluorinated sulfonic acid ionomer membranes, which provide ion-selectivity and barrier properties to produced gases. Unfortunately, there is limited information to determine which factors should be satisfied for CA applications. In this study, the influences of PFSA membranes on CA performances are disclosed. They include ion transport behaviors, gas evolution capability, and chemical/electrochemical resistances under CA operation conditions.

• Journal of the Korean Chemical Society
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• v.37 no.1
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• pp.43-48
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• 1993

The $^1H-NMR$ spectra of the NH-group were obtained for N-ethylacetamide (NEAA) in the series of n-alcohols over a temperature range of 310∼350K by using NMR spectroscopy. The $^1H-NMR$ lineshape coupled to $^{14}N$ nucleus were analyzed to obtain the reorientational correlation times ${\tau}_c$ of NEAA. The data indicate that the coupling of solute and solvent decreases as the chain length of n-alcohols increases. But in the n-alcohols the reorientational motion depends almost linearly on η/T of solvents over our temperature range. The results are discussed in the context of the subslip phenomenon.

• The KSFM Journal of Fluid Machinery
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• v.19 no.4
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• pp.39-42
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• 2016

A PFA lined ball valve, which is machined with fluorinated resin PFA to its inner part for improving corrosion resistance, non-stickness, heat-resistance, has been widely used to the chemical/pharmaceutical industries, the semiconductor/LCD manufacturing processes, etc. with the high purity chemicals as working fluid. EPA stated that 60% of all fugitive emissions come from the valve stem packing in a typical petroleum or chemical processing plant. They monitor regulated components for leaks and maintain seal performance at acceptable levels. Korean industrial standards only deals with the bubble test for in-line leakage of valves, which has the detectable leak rate of $10^{-4}$ [$mbar{\cdot}L{\cdot}s^{-1}$], therefore, it is not sufficient to check fugitive emissions. In this study, we conducted Helium leak detection from a PFA lined ball valve and evaluated fugitive emissions according to ISO 15848-1, which has the detectable leak rate of $10^{-9}$ [$mbar{\cdot}L{\cdot}s^{-1}$], for manufacturing the high-reliable PFA lined ball valves against fugitive emissions.