• Applied Chemistry for Engineering
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• v.23 no.5
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• pp.480-484
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• 2012

Concrete, the mixture of cement, sand, gravel and water, is a suspension substance extensively used to construct building materials. When a concrete mortar is applied to the underwater construction, the rheology of concrete is of great importance to its flow performance, placement, anti-washout and consolidation. In this research, the anti-washout and rheological properties of concrete have been investigated with concrete admixtures prepared by adding anionic surfactants, cationic surfactants, and polymeric thickeners. The concrete mortar formulated by pseudo-polymeric systems with the electrostatic association of anionic and cationic surfactants, showed high viscosities and suitable anti-washout properties, but poor pumpabilities. The addition of poly methyl vinyl ether to the mixed surfactant system exhibits synergistic effects by improving the concrete mortar properties of the concrete mortar such as fluidity, visco-elastic property, self-leveling, and anti-washout.

• Applied Chemistry for Engineering
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• v.27 no.5
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• pp.521-526
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• 2016

Some thiadiazole and dithiocarbamate derivatives were desinged and synthesized in order to study the potential use as anti- wear additives. Their anti-wear properties in three different base oils (DB-51, soybean, and 100 N) were evaluated using a four-ball wear tester (ASTM D4172). The solubilities of dithiocarbamate derivatives in the base oils were better than those of thiadiazole derivatives. The compounds containing oleoyl group rather than nonanoyl group gave good anti-wear properties. The solubilities and anti-wear properties were explained by the polarity of the compounds.

• Korean Chemical Engineering Research
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• v.47 no.1
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• pp.38-45
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• 2009

In this study, interfacial properties were measured for imidazoline type cationic surfactant system which has been widely used as a fabric softener, a dispersant, an anti-static agent, a bleach activator, and an emulsifier. The CMC of imidazoline surfactant was near $6{\times}10^{-5}mol/L$ and the surface tension at CMC was about 32 mN/m. It was found that surface tension was not affected by surfactant concentration but decreased with an increase in pH. The interfacial tension between 1 wt% aqueous solution and n-dodecane was shown to be about 0.01 mN/m and equilibration time was not affected by pH. Phase behavior experiment in a binary aqueous surfactant system showed that only micellar solution of $L_1$ phase was found under conditions of temperature and pH investigated during this study. Only a two-phase region consisting of lower-phase microemulsion in equilibrium with excess oil phase existed under the same conditions, when oil was added to the binary surfactant system. The foam stability measured with 1 wt% surfactant solution increased with pH, which is consistent with surface tension measurement result. QCM(quartz crystal microbalance) measurement showed that surfactant adsorption increased with surfactant concentration but decreased with pH. According to the friction measurement, best fabric softening effect by imidazoline surfactant system was found under alkali conditions.

• Journal of Bio-Environment Control
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• v.12 no.4
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• pp.195-199
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• 2003

In polyethylene film house treated with surfactants(SF316+FB0800), waterdrops attached on film surface were absorbed to filter paper of 9 cm in diameter and measured 1.21 mL in control, 0.15 mL in 1% and 0.07 mL in 2% on December 10 at 10:00, 2002. However, there was no clear difference between surfactant concentrations 1% and 2%, And the most waterdrop was measured at 10:00 in daytime. As the air temperature was higher in greenhouse, waterdrop was sweled. So, the least waterdrop was measured at 14:00. In greenhouse covered with surfactants concentrated 1% and 2%, transmittances of solar radiation were 9.3% and 12.9% higher than control, respectively. In air temperature and relative humidity, there were no significant difference in all greenhouse. in forenoon, the air temperature and relative surfactant treated film greenhouse tended 1~2$^{\circ}C$ warmer than that of control. However, sil temperatures of surfactant treated film greenhouse tended 3~4$^{\circ}C$ warmer than that of control. During winter, the lettuce growth in surfactant treated film greenhouse was faster than that of control. However, there was no difference between surfactant concentrations of 1% and 2%.

• Environmental Analysis Health and Toxicology
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• v.30
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• pp.6.1-6.7
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• 2015

Objectives This study aimed to estimate the effects of 4-nonylphenol (NP), a ubiquitously present surfactant in aquatic environments, on the anti-oxidant systems of the liver in the Far Eastern catfish Silurus asotus. Methods Changes in biochemical parameters involved in glutathione (GSH)-related and other anti-oxidant systems were analyzed following 4 weeks of 4-NP administration (0.1 and 1.0 mg/kg diet) via a formulated diet to catfish. Results 4-NP exposure induced an elevation in hepatic lipid peroxide levels and an accompanying decrease in reduced state GSH after 2 weeks, suggesting pro-oxidant effects of the chemical in catfish. This oxidative stress was associated with an inhibition of the GSH-utilizing enzyme glutathione peroxidase at the same time point. This inhibition was restored after 4 weeks. The activities of other anti-oxidant enzymes, i.e., glutathione reductase, superoxide dismutase and catalase were increased after 4 weeks. These enzyme increases occurred more strongly at the higher 4-NP concentration (1.0 mg/kg diet). Conclusions 4-NP given to catfish at 0.1 to 1.0 mg/kg diet, concentrations relevant to environmental levels, depletes the endogenous anti-oxidant molecule GSH and temporarily inhibits GSH-related anti-oxidant enzymes. Such declines in anti-oxidant capacity and elevated oxidative stress seem to be compensated eventually by subsequent activation of various anti-oxidant enzyme systems.

• Korean Journal of Materials Research
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• v.28 no.2
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• pp.101-107
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• 2018

Li-incorporated ZnO thin films were deposited by using ultrasonic-assisted spray pyrolysis deposition (SPD) system. To investigate the effect of Li-incorporation on the performance of ZnO thin films, the structural, electrical, and optical properites of the ZnO thin films were analyzed by means of X-ray diffraction (XRD), field-emssion scanning electron microscopy (FE-SEM), Hall effect measurement, and UV-Vis spectrophotometry with variation of the Li concentraion in the ZnO sources. Without incorporation of Li element, the ZnO surface showed large spiral domains. As the Li content increases, the size of spiral domains decreased gradually, and finally formed mixed small grain and one-dimensional nanorod-like structures on the surface. This morphological evolution was explained based on an anti-surfactant effect of Li atoms on the ZnO growth surface. In addition, the Li-incorporation changed the optical and electrical properties of the ZnO thin films by modifying the crystalline defect structures by doping effects.

• Journal of the Korean Ceramic Society
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• v.40 no.8
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• pp.811-817
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• 2003

Recently, application fields of non-metallic minerals by utilizing their structure properties are broadening. Especially, layered minerals have not only excellent shielding or covering ability but also absorbing and storing characteristics of chemical elements between a layers. We considered about the above mentioned characteristics and added functional substances onto their surfaces for the preparation of new environmentally friendly functional materials. In this study, natural graphite and sericite were mainly used to produce for the new environmentally friendly functional building materials. Graphite surfaces were modified with a surfactant (Alkyl Benzyle Demethyle Ammonium Chloride) for anti-bacillus and penicillium. Surface modification mechanism are that primary adsorption by differential zeta potential between graphite and ABDM and secondary adsorption by interaction between surfactant chains take place. Surfactant layers were fully formed and it was expected up to 99.7% up the efficiency of anti-bacillus and penicillium. Also the prepared functional samples have a effect to improve a various efficiency such as electromagnetic wave shield(up to 95%), deodorization(up to 80%), heat storage(5%) etc.

• Applied Chemistry for Engineering
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• v.29 no.5
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• pp.620-625
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• 2018

Liquid detergent based on sodium lauryl ethoxy sulfate (SLES) as main ingredient sometimes met gelling film on the surface when it is opened in the air. It was assumed because of the change of phase diagram of micelle by concentration change of surfactant, major ingredient of detergent when the water of detergent is evaporated. SLES showed strong hexagonal liquid crystal (LC) in 30~60 wt%, and lamellar LC over 60 wt%. In this research surface gelling formation of liquid detergent which is based on SLES as main ingredient was because of water evaporation. As water of detergent was evaporated, concentration of surfactant became higher. It was checked that surface gelling was LC of mixed surfactant system. Conclusionally we applied alpha olefin sulfonate (AOS) having good solubility, Sodium secondary alkane sulfonate (SAS) preventing hexagonal LC and hydrotrope sodium xylene sulfonate (SXS) and PEG1500 in order to prevent gelling film in SLES based liquid detergent. Like this, improved formula 4 and 5 can prevent the formation of gelling film on the surface of liquid detergent when it is opened in the air.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2003.11a
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• pp.139-148
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• 2003

In this study, biodegradable base Li-greases were prepared by using Li-soap thickener and vegetable oils such as soybean oil, rapeseed oil, castor oil and synthetic ester. Also, EP-greases were formulated by blending base Li-greases, anti-wear additives, EP additives, anti-oxidants and corrosion inhibitor etc. And EP-greases were characterized by analysing physical properties such as worked penetration, dropping point, 4-ball wear, extreme pressure, thermal properties etc. Biodegradability of base Li-greases and EP-greases were evaluated by CEC-L-33-A-93 method using several inoculums of domestic sewage treatment plant. As the results, biodegradability of vegetable oils were shown at the range of 97.1 to $98.4\%$. And biodegradability of base Li-greases and EP-greases were $86.2\%\;\~\;89.3\%\;and\;83.4\%\;\~\;90.0\%$ which were lower value than those o( vegetable oils due to effect of Li-soap thickener, respectively. Therefore, the EP-greases prepared in this study were easily biodegraded by microorgnism.

• Journal of Industrial and Engineering Chemistry
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• v.67
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• pp.140-147
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• 2018

The performance of a hydrate anti-agglomerant (AA) on cyclopentane (CyC5) hydrate anti-agglomeration at various concentrations (0-1 wt%, based on the oil phase) using MMF apparatus has been investigated. At low AA concentrations up to 0.01 wt%, the AA reduces the cohesion force (capillary force) by reducing the CyC5-water interfacial tension. At concentrations higher than 0.1 wt%, hydrate hydrophobicity alternation and AA's thermodynamic inhibition effects are the main part of AA's mechanism. Additionally, a "temporary agglomeration" phenomenon caused by surface melting of the hydrate particles is also observed, which may indicate the AA's weak ability to produce stable water-CyC5 interface.