• Journal of the Korean institute of surface engineering
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• v.28 no.5
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• pp.259-266
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• 1995

In order to manufacture an attractive waste glass for the permanent and secure disposal of high-level radioactive waste, the complex composition of the simulated nuclear waste glass PNL-7668 was simplified to a composition of sodium borosilicate glass. The substitutions of $Fe_2O_3$ and $Al_2O_3$ were added to examine on the leaching characteristics of simulated nuclear waste glass with variable composition. The leach tests for these glasses were performed according to 'MCC-1, Static Leach Test Procedure' in acid and basic solution. In this study, for the $Al_2O_3$-containing glasses, Na ion release from these glasses was higher in acid solution than in basic solution. As the content of $Fe_2O_3$ was increased in glasses, Na ion release was increased in acid solution, in spite of decrease of amount of total mass diminution.

• Journal of the Korean Ceramic Society
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• v.47 no.5
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• pp.412-418
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• 2010

This paper presents the results of experimental work on both mechanical properties and durability of concrete or mortar incorporating silica fume. The aim of this study was to investigate the effect of replacement of silica fume on the performance of hardened concrete or mortar. The replacement levels of silica fume that replaced cement in this work were 0%, 5%, 10% and 15%, respectively. The results of this study indicate that both mechanical properties and durability of concrete are greatly dependent on the replacement levels of silica fume. As the replacement level of silica fume increased, the mechanical properties including compressive and flexural strengths, and static modulus of elasticity were proportionally enhanced. Furthermore, it was found that silica fume had some beneficial effects on the resistances to both chloride ions penetration and sodium sulfate attack. However, it exhibited poor resistances to both freezing-thawing action and magnesium sulfate attack.

• Korea-Australia Rheology Journal
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• v.17 no.4
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• pp.191-198
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• 2005

The static and dynamic rheological behavior of concentrated sodium dodecylsulfate (SDS) stabilized, deformability controllable polydimethylsiloxane (PDMS) emulsions is reported and comparisons made with silica (hard sphere) suspensions. Steady-mode measurements indicate 'hard' (viscoelastic) droplets behave as hard spheres, while 'soft' (viscous) droplets induce structural flexibility of the emulsion against shear. Dynamic-mode measurements reveal that viscoelasticity of droplets provides the great magnitude of elasticity for the 'hard' emulsion, while formation of planar films between droplets is the origin of the elasticity of 'soft' emulsions. Combination of steady and dynamic rheological behavior has enabled depiction of droplet structure evolution in relation to the shear stress applied, especially by taking advantage of the normal force that reflects the transient deformation of droplets.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.7
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• pp.665-671
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• 2017

The alkali-Metal Thermal-to-electric Converter (AMTEC) is one of the promising static energy conversion technologies for the direct conversion of thermal energy to electrical energy. The advantages over a conventional energy converter are its high theoretical conversion efficiency of 40% and power density of 500 W/kg. The working principle of an AMTEC battery is the electrochemical reaction of the sodium through an ion conducting electrolyte. Sodium ion pass through the hot side of the beta"-alumina solid electrolyte (BASE) primarily as a result of the pressure difference. This pressure difference across the BASE has a significant effect on the overall performance of the AMTEC system. In order to build the high pressure difference across the BASE, hermeticity is required for each joined components for high temperature range of $900^{\circ}C$. The AMTEC battery was manufactured by utilizing robust joining technology of BASE/insulator/metal flange interfaces of the system for both structural and electrical stability. The electrical potential difference between the anode and cathode sides, where the electrons emitted from sodium ionization and recombined into sodium, was characterized as the open-circuit voltage. The efforts of technological improvement were concentrated on a high-power output and conversion efficiency. This paper discusses about the joining and performance of the AMTEC systems.

• Proceedings of the KOSOMBE Conference
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• v.1995 no.11
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• pp.26-33
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• 1995

Silicone Rubber (SR)-based potassium- and sodium-selective solid-state electrodes have been developed for the portable blood electrolyte analyzer system. The electrochemical performance of these electrodes have been evaluated with a static experimental setup and with the newly developed blood electrolyte analyzer system (model; HS603). It has been shown that their potentiometric properties are essentially comparable to those of PVC-based ion-selective electrodes, but with greatly improved lifetime (200 and 40 days for potassium and sodium sensors, respectively) and potential stability (within $\pm0.1$ mV). Clinical tests have been performed with real serum samples and the results have been compared with those obtained from Ciba-Corning BGA 288 system; correlations were excellent, proving its practical utility as a new commercial system.

• Applied Chemistry for Engineering
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• v.29 no.5
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• pp.524-532
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• 2018

In this study, two types of amino acids-based anionic biosurfactants such as potassium cocoyl glutamate (CTK) and sodium cocoyl glutamate (CTN) were synthesized from coconut oils and the structure elucidation of CTK and CTN was carried out by using FT-IR, $^1H-NMR$ and $^{13}C-NMR$ spectrophotometries. Measurements of interfacial properties such as static and dynamic surface tensions and emulsification activity showed that both CTK and CTN were surface-active and effective in lowering the interfacial free energy. In particular, the CTK surfactant was found to be more efficient in reducing the interfacial free energy since the larger number of CTK molecules was preferentially adsorbed at the air-water interface due to the higher hydrophobicity and larger mobility of CTK than those of using CTN, indicating possible uses in cosmetics and household products formulation.

• Journal of Microbiology and Biotechnology
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• v.31 no.7
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• pp.967-977
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• 2021

A total of 37 bacterial isolates were obtained from dye-contaminated soil samples at a textile processing factory in Nakhon Ratchasima Province, Thailand, and the potential of the isolates to decolorize and biotransform azo dye Reactive Red 141 (RR141) was investigated. The most potent bacterium was identified as Paenibacillus terrigena KKW2-005, which showed the ability to decolorize 96.45% of RR141 (50 mg/l) within 20 h under static conditions at pH 8.0 and a broad temperature range of 30-40℃. The biotransformation products were analyzed by using UV-Vis spectrophotometry and Fourier-transform infrared spectroscopy. Gas chromatography-mass spectroscopy analysis revealed four metabolites generated from the reductive biodegradation, namely sodium 3-diazenylnaphthalene-1,5-disulfonate (I), sodium naphthalene-2-sufonate (II), 4-chloro-1,3,5-triazin-2-amine (III) and N¹-(1,3,5-triazin-2-yl) benzene-1,4-diamine (IV). Decolorization intermediates reduced phytotoxicity as compared with the untreated dye. However, they had phytotoxicity when compared with control, probably due to naphthalene and triazine derivatives. Moreover, genotoxicity testing by high annealing temperature-random amplified polymorphic DNA technique exhibited different DNA polymorphism bands in seedlings exposed to the metabolites. They compared to the bands found in seedlings subjected to the untreated dye or distilled water. The data from this study provide evidence that the biodegradation of Reactive Red 141 by P. terrigena KKW2-005 was genotoxic to the DNA seedlings.

• The Korean Journal of Pesticide Science
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• v.9 no.3
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• pp.262-267
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• 2005

In order to commercialize Paenibacillus sp. AC-1 and to minimize its harmful side effects, four granular formulations were prepared using AC-1 powder, adjuvant, and carrier and then their physicochemical properties of the formulations were investigated. Out of the carriers tested, the best one was talc for the formulation. Viable cells was stabilized during the formulating process. Viable cells in the granules formulated with Paenibacillus sp. AC-1 powder were stabilized at storage temperature range ($4{\sim}50^{\circ}C$) after 12 weeks. The release rate of viable cells from granules into water under a static condition were eluted over 90% in 7 hours and breakdown rates of particle were 100% in 1 day. Among the tested formulations, granular formulation comprising of 20% of Paenibacillus sp. AC-1 powder, 7% of polycarboxylate as surface active agent, 1% of sodium polyacrylate as adjuvant, the rest as carrier showed to be best.

• Korean Journal of Environmental Biology
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• v.34 no.3
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• pp.208-211
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• 2016

Essential oils (EOs) extracted from plants possess various biological activities and have been considered as natural insecticides due to their potent insecticidal activities. In regard to develop natural insecticides, EOs are formulated as an emulsifiable concentrate and their acute toxicity against to fishes were determined in a static condition using Cyprinus carpio. Coriander EO was used as an active ingredient mixed with ethanol for solvent and various surface active agents. The tested EOs were obtained from a commercial market, and three different extractions were also undertaken to produce EO using steam distillation, solvent extraction, and supercritical fluid extraction. Among the emulsifiable concentrate including a commercial coriander EO, surface active agents such as Tween 80, sodium dodecyl benzene sulfonate (SDBS), and mixture of SDBS and Nonidet showed acute toxicity to the fish. With the three different EO extraction, coriander EO obtained from supercritical fluids with Triton X-100 exhibited acute toxicity to C. carpio. Taken together, Tetgitol and Nondet are considered as surface active agents for the emulsifiable formulation of coriander EO.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.264-271
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• 2023

In this study, ASCO^Ⓡ SLES-430 surfactant was synthesized by adducting 3 moles of ethylene oxide and 1 mole of propylene oxide to lauryl alcohol followed by a sulfation process, and the structure of the synthesized ASCO^Ⓡ SLES-430 was elucidated by performing FT-IR, ¹H-NMR and ¹³C-NMR analyses. Interfacial properties such as critical micelle concentration, static surface tension, emulsification index, and contact angle were measured, and environmental compatibility indices such as oral toxicity and skin irritation were also estimated for ASCO^Ⓡ SLES-430. Both results were compared with ASCO^Ⓡ SLES-226 and ASCO^Ⓡ SLES-328 SLES surfactants possessing 2 moles and 3 moles of ethylene oxide, respectively. In particular, both foaming ability and foam stability were evaluated for ASCO^Ⓡ SLES-430 and compared with ASCO^Ⓡ SLES-226 and ASCO^Ⓡ SLES-328, which have been widely used in detergent products, in order to test the potential applicability of ASCO^Ⓡ SLES-430 in detergent product formulation for a small capacity built-in washing machine.