• Proceedings of the Korean Fiber Society Conference
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• 2003.10b
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• pp.241-242
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• 2003

Silver has antibacterial property on bacteria of about 650 kinds and has been well known as non-toxic and non-tolerance in natural state. Recently, silver has been applied disinfection and antibacterial property to everyday life as health foods, filter, and exclusion of pollution. Nano-sized silver particle have very small size (〈10nm) and wide surface area per unit volume. PE/PP nonwovens used as back sheet or coverstock of baby diaper, adult diaper, sanitary napkin, and wiper. (omitted)

• Journal of the Korea Safety Management & Science
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• v.21 no.4
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• pp.45-49
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• 2019

The basalt fiber is expected to become a trend for industrial fibers as they have better properties of heat-resistant, non-combustion, absorbent, soundproof, moistureproof, lightweight, corrosion resistant, and high strength properties. Also, the fiber is found to be non-toxic and harmless to the human body. Therefore, in this study, we analyzed the chemical and mineral compositions of powdered sludge of basalt produced at seven sites on Jeju Island for the development of fire resistance insulating material for a building. The results showed that the basalt stone sludge is made from only sodium calcium aluminum silicate and ferridioside components unlike the basalt rock.

• International Journal of Precision Engineering and Manufacturing
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• v.9 no.4
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• pp.63-65
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• 2008

The increased interest in reducing the environmental effects caused by releasing organic compounds and aqueous waste has motivated the development of polymeric materials in supercritical fluids. Recently, supercritical fluids have been used in material synthesis and processing because of their special properties, such as high diffusivity, low viscosity, and low surface tension. Supercritical carbon dioxide is the most attractive because it is non-toxic, non-flammable, and has moderate critical temperature and critical pressure values. Supercritical carbon dioxide can also swell most polymers. In this study, we prepared polymer/clay nanocomposites using supercritical fluids. Cloisites 10A, 15A, 25A, and 30B used in this study are montmorillonites modified with a quaternary ammonium salt. The nanocomposites of polymer/clay were characterized by X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry.

• Toxicological Research
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• v.25 no.1
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• pp.9-15
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• 2009

Historically, research in toxicology has utilized non-human mammalian species, particularly rats and mice, to study in vivo the effects of toxic exposure on physiology and behavior. However, ethical considerations and the overwhelming increase in the number of chemicals to be screened has led to a shift away from in vivo work. The decline in in vivo experimentation has been accompanied by an increase in alternative methods for detecting and predicting detrimental effects: in vitro experimentation and in silico modeling. Yet, these new methodologies can not replace the need for in vivo work on animal physiology and behavior. The development of new, non-mammalian model systems shows great promise in restoring our ability to use behavioral endpoints in toxicological testing. Of these systems, the zebrafish, Danio rerio, is the model organism for which we are accumulating enough knowledge in vivo, in vitro, and in silico to enable us to develop a comprehensive, high-throughput toxicology screening system.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.15 no.3
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• pp.1-6
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• 2019

The basalt fiber, which is found to be non-toxic and harmless to the human body, is expected to become a trend for industrial fibers as they have better properties of non-combustion, heat-resistant, soundproof, absorbent, moistureproof, wear-resistant, corrosion resistant, lightweight, and high strength properties. Thus, in this study, we analyzed the chemical compositions of basalt produced at seven sites on Jeju Island for making a high value inorganic insulation material. The results showed that the MgO content of basalt collected from the eastern part of Jeju Island was higher than 7.5 percent, while that of the western region was less than 6 percent.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.277.1-277.1
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• 2002

The purpose of this study was to develop PEl-based gene carriers with optimal serum stability and reduced cytotoxicity. PEl is an efficient gene transfer agent with the ability of DNA condensation and endosome escape: however; use of the polymer in vivo is hampered by signigicant reduction in transfection activity by the presence of serum. Chitosan is a non-toxic. biodegradable and biocompatible polymer with hydrophilic functional groups so it may provide a physical stability against challenge by serum proteins. (omitted)

• Advances in Energy Research
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• v.8 no.4
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• pp.233-241
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• 2022

Biodiesel is a non-polluting and non-toxic energy source that can replace conventional diesel. However, the higher production cost and raw material scarcity became challenges that obstruct the commercialization of biodiesel production. In the current investigation, fried cooking oil is used for biodiesel production in a hydrodynamic cavitation reactor, thus enhancing raw material availability and helping better waste oil disposal. However, due to the cavitation effect inside the reactor, the hydrodynamic cavitation reactor can give biodiesel yield above 98%. Thus, the use of orifice plates (having a different number of holes for cavitation) in the reactor shows more than 90% biodiesel yield within 10 mins of a time interval. The effects of rising temperature at different molar ratios are also investigated. The five-hole plate achieves the highest yield for a 4.5:1 molar ratio at 65℃. And the similar result is predicted by the response surface methodology model; however, the optimized yield is obtained at 60℃. The investigation will help understand the effect of hydrodynamic cavitation on biodiesel yield at different molar ratios and elevated temperatures.

• Fire Science and Engineering
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• v.33 no.4
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• pp.28-34
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• 2019

Regardless of the ignition source, the main factors affecting the spread of flames to the human body are combustibles. The sound absorption material, which is the finishing material used in music institutes and karaoke rooms, consists of polyurethane that generates a large amount of toxic gas with a high amount of combustion gases during a fire. Still, the current law does not require the use of impregnated finishing materials for tutoring services with less than 100 users. In this study, the rate of flame diffusion was measured using the MultiRaelite composite gas measuring instrument (target substance VOC, HCHO, SO₂, CO₂, CO, HCN, and NO₂) for the collection of sound-absorbing materials installed in the actual music academy. The results showed that the toxic gas found in this experiment exceeded the allowable concentration of TWA (Time Weighted Average) and STEL (Short Term Exposure Limit). In addition, a comparative combustion test of the general sound absorber and non-combustion sound absorbing materials on the market showed wide differences in ignition and diffusion. Therefore, based on the results of the experiment, private institutes with less than 100 users should be mandated to use non-combustion sound absorbing materials.

• Biomolecules & Therapeutics
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• v.6 no.1
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• pp.14-19
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• 1998

In the present study, we intended to investigate whether cationic polyamines including poly-L-Iysine (PLL) and poly-L-arginine (PLA) induce cytotoxicities to cultured hamster tracheal surface epithelial (HTSE) cells. Confluent HTSE cells were chased for 30 min in the presence of PLL or PLA of different molecular weights. Possible cytotoxicities of PLL or PLA were assessed by measuring both Lactate Dehy- drogenase (LDH) release during treatment and the number of floating cells after treatment and by checking the possible changes on the morphology of HTSE cells during treatment. The results were as follows: in the case of treatment of PLL or rLA of which molecular weight is about 78,000 and 92,000, respectively, (1) there was significant release of LDH during treatment, (2) the number of floating cells were significantly increased after treatment and (3) there were significant changes on the morphology of cultured HTSE cells. However, in the case of PLL or PLA of which molecular weight is under 10,000 (about 9,600 and 8,900, respectively), no significant signs of cytotoxicities mentioned above were detected. We found that cationic polyamines might be non-toxic under specific range of molecular weights and suggest that the cytotoxicity of cationic polyamine might depend on the molecular sizes of each cationic polyamine.

• Polymer(Korea)
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• v.27 no.3
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• pp.169-175
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• 2003

Pyrophosphoric lactone modified polyester (PATT) containing two phosphorous functional groups in one unit structure was synthesized to prepare a non-toxic reactive flame-retardant coatings. Then the PATT was cured at room temperature with isocyanate, toluene diisocyanate-isocyanurate , to get a two-component polyurethane flame-retardant coatings (PIPUC). Comparing physical properties of the films of PIPUC with those of film of non-flame-retardant coatings, there was no deterioration observed in physical properties by the introduction of a flame-retarding component into the resin. We found that the char lengths measured by 45$^{\circ}$ Meckel burner method were 3.1∼4.4 cm and LOI values recorded 27∼30%. These results indicate that the coating prepared in this study is a good flame-retardant. The surface structure of coatings investigated with SEM does not show any defects and phase separation.