• Advances in concrete construction
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• v.16 no.6
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• pp.303-316
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• 2023

Using industrial wastes and construction and demolition (C&D) wastes is potentially advantageous for concrete production in terms of sustainability improvement. In this paper, a sustainable Self-Compacting Concrete (SCC) made with industrial wastes and C&D wastes was proposed by considerably replacing natural counterparts with recycled coarse aggregates (RCAs) and supplementary cementitious materials (SCMs) (i.e., Fly ash (FA), ground granulated blast furnace slag (GGBS) and silica fume (SF)). A total of 12 SCC mixes with various RCAs and different combination SCMs were prepared, which comprise binary, ternary and quaternary mixes. The mechanical properties in terms of compressive strength and static elasticity modulus of recycled aggregates (RA-SCC) mixes were determined and analyzed. Microstructural study was implemented to analyze the reason of improvement on mechanical properties. By means of life cycle assessment (LCA) method, the environmental impacts of RA-SCC with various RCAs and SCMs were quantified, analyzed and compared in the system boundary of "cradle-to-gate". In addition, the comparison of LCA results with respect to mechanical properties was conducted. The results demonstrate that the addition of proposed combination SCMs leads to significant improvement in mechanical properties of quaternary RA-SCC mixes with FA, GGBS and SF. Furthermore, quaternary RA-SCC mixes emit lowest environmental burdens without compromising mechanical properties. Thus, using the combination of FA, GGBS and SF as cement substitution to manufacture RA-SCC significantly improves the sustainability of SCC by minimizing the depletion of cement and non-renewable natural resources.

• Applied Chemistry for Engineering
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• v.8 no.3
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• pp.357-364
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• 1997

The objective of this study was to find optimum nonionic surfactants for clean up of soils contaminated by hydrocarbon oils. PIT(phase inversion temperature) measurements in ternary systems containing pure hydrocarbons, pure nonionic surfactants, and water were carried out and interfacial tensions were measured as a function of time for n-hexadecane oil drops brought into contact with various mixtures of nonionic surfactant and water. Batch surfactant washing experiments were performed based on the measurement, results of PIT and interfacial tension and the results showed that maximum removal of n-hexadecane occurred at the PIT of the system. For the $C_{12}E_5(C_{12}H_{25}O(CH_2CH_2O)_5H)$ system, maximum n-hexadecane removal of 73.4% occurred at the PIT of $52^{\circ}C$. In contrast, n-hexadecane removal at $25^{\circ}C$ and at $60^{\circ}C$, each corresponding to the conditions of below PIT and above PIT of the system, was found to be 57.1% and 57.0% respectively. The maximum removal of a hydrocarbon at the PIT of a system, where the hydrophilic and hydrophobic properties are balanced, was found to be due to the existence of high oil solubilization into a middle-phase microemulsion and ultralow interfacial of the order of $10^{-2}$ to $10^{-3}$ dyne/cm between middle-phase microemulsion and excess oil phase.

• Journal of Life Science
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• v.29 no.9
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• pp.949-954
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• 2019

Membrane topology is a key characteristic of membrane proteins. We previously reported the cloning of the chromosome 4 open-reading frame 32 (C4orf32) gene as a potential membrane protein; however, the cellular localization and membrane topology of C4orf32 was as yet unknown. In this study, we found that green fluorescent protein (GFP) fused to the C-terminus of C4orf32 (C4orf32-GFP) was localized to the endoplasmic reticulum (ER). We applied three tools to identify determinants of C4orf32 topology: protease protection, fluorescence protease protection (FPP), and an inducible system using the ternary complex between FK506 binding protein 12 (FKBP), rapamycin, and the rapamycin-binding domain of mTOR (FRB) (the FRB-rapamycin-FKBP system). Using protease protection and FPP assays, we found that the GFP tag in C4orf32-GFP was localized to the cytoplasmic surface of the ER membrane of HeLa cells. Protease protection and FPP assays are useful and complimentary tools for identifying the topology of GFP fusion membrane proteins. The FRB-rapamycin-FKBP system was also used to study the topology of C4orf32. In the absence of rapamycin, a monomeric red fluorescent protein-FKBP fusion (mRFP-FKBP) and C4orf32-GFP-FRB were localized to the cytoplasm and the ER membrane, respectively. However, in the presence of rapamycin, the mRFP-FKBP was shifted from the cytoplasm to the ER and colocalized with the C4orf32-GFP-FRB. These results indicate that the FRB moiety is facing the cytoplasmic surface of ER membrane. Overall, our results clearly suggest that C4orf32 belongs to the family of type I ER resident membrane proteins.

• Journal of Life Science
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• v.31 no.5
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• pp.502-510
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• 2021

The objective of this study was to develop a novel ticagrelor-loaded self-nanoemulsifying drug delivery system with an enhanced solubility and dissolution rate. Numerous oils and surfactants were screened, then medium chain triglyceride (MCT) oil and the surfactants polyoxyethylene sorbitan monooleate (Tween 80) and Labrafil M1944CS were selected for the preparation of the ticagrelor-loaded self-nanoemulsifying drug delivery system. A pseudo-ternary phase diagram was constructed to detect the nanoemulsion region. Of the various formulations tested, the liquid SNEDDS, composed of MCT (oil), Tween 80 (surfactant), and Labrafil M1944CS (cosurfactant) at a weight ratio of 20/70/10 produced the smallest emulsion droplet size (around 20.56±0.70 nm). Then, particle size, polydispersity, and zeta potential were measured using drugs containing liquid SNEDDS. The selected ticagrelor-loaded liquid SNEDDS was spray-dried to convert it into a ticagrelor-loaded solid SNEDDS with a suitable inert carrier, such as silicon dioxide, calcium silicate, or magnesium aluminometasilicate. The solid SNEDDS was characterized by scanning electron microscopy, transmission electron microscopy, and in vitro dissolution studies. SEM, PXRD, and DSC results suggested that amorphous ticagrelor was present in the solid SNEDDS. Also, the solid SNEDDS significantly increased the dissolution rate of ticagrelor. In particular, the emulsion particle size and the polydispersity index of the solid SNEDDS using silicon dioxide (SS1) as a carrier was the smallest among the evaluated solid SNEDDS, and the flowability and compressibility result of the SS1 was the most suitable for the manufacturing of solid dosage forms. Therefore, solid SNEDDS using silicon dioxide (SS1) could be a potential nano-sized drug delivery system for the poorly water-soluble drug ticagrelor.

• Journal of Pharmaceutical Investigation
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• v.41 no.2
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• pp.103-109
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• 2011

The objective of the study was to prepare self-microeulsifying drug delivery system (SMEDDS) incorporating atorvastatin calcium and evaluate its properties and oral bioavailability. Solubility of atorvastatin in various vehicles was determined. Pseudo-ternary phase diagrams were constructed to identify the good self-emulsification region. The droplet size distributions of the resultant emulsions were determined by dynamic light scattering measurement. The mean droplet size of chosen formulation (20% ethyl oleate, 40% tween-80, 40% Carbitol$^{(R)}$) was $23.4{\pm}1.3$ nm. The SMEDDS incorporating atorvastatin calcium appeared to be associated with better performance in dissolution and pharmacokinetic studies, compared with raw atorvastatin calcium. In dissolution test, the release percentage of atorvastatin from SMEDDS mixture could rapidly reach more than 95% within 3 min. Oral $AUC_{0{\rightarrow}8hr}$ values in SD rats was $1994{\pm}335\;ng{\cdot}hr/mL$, which significantly increased (P<0.05) compared with raw atorvastatin calcium. The SMEDDS formulation was relatively stable when stored at $4^{\circ}C$ during 3 months. Our studies illustrated the potential use of SMEDDS for the delivery of hydrophobic compounds, such as atorvastatin, by the oral route.

• Applied Chemistry for Engineering
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• v.29 no.1
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• pp.28-36
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• 2018

Adsorption experiments of three target gases such as acetone, benzene, and methyl mercaptan (MM) were carried in a continuous reactor using the activated carbon prepared from waste citrus peel. In a single gas system, the breakthrough time obtained from using the activated carbon (WCAC) prepared from waste citrus peel. In a single gas system, the breakthrough time obtained from the breakthrough curve decreased with increasing the inlet concentration and flow rate, but increased with respect to the aspect ratio (L/D). Adsorbed amounts of the target gases by WCAC increased as a function of the inlet concentration and aspect ratio. However, adsorbed amounts with the increase of the flow rate were different depending upon target gases. Results from the breakthrough time and adsorbed amount showed that the affinity for WCAC was the highest in benzene, followed by acetone and then MM. On the other hand, in the binary and ternary systems, the breakthrough curve showed a roll-up phenomenon where the adsorbate having a small affinity for WCAC was replaced with the adsorbate with a high affinity. The adsorption of acetone on WCAC was more strongly affected when mixing with the nonpolar benzene than that of using sulfur compound MM.

• Applied Chemistry for Engineering
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• v.16 no.6
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• pp.778-784
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• 2005

It has been found that the addition of cosurfactant is necessary in order to expand three phase region containing middle phase microemulsion in ternary systems containing alkyl ethoxylate (AEO) nonionic surfactant, commercial lubricant and water. Phase behavior in the surfactant systems with addition of cosurfactant over a temperature range of 30 to $60^{\circ}C$ showed different trends depending on surfactant, temperature and chain length of alcohol added. For the $C_{12}E_4$ system, addition of n-pentanol and n-hexanol both produced a three phase region over a wide range of temperatures but the middle-phase formed was found to be a $L_3$ or D' phase which would not facilitate solubilization of high molecular weight lubricants. On the other hand, for the $C_{12}E_5$ system, the middle-phase microemulsion was found to be formed with addition of a rather long-chain alcohol such as n-hexanol, n-heptanol, n-octanol, or n-nonanol. The results shown with the addition of cosurfactant was understood in connection with interfacial tension measurements and composition analysis. The inability of the hydrocarbon region of the surfactant films to incorporate the large lubricant molecules and high solubility of a hydrophobic surfactant are thought to be the chief reasons for poor solubilization with D' phase.

• Applied Chemistry for Engineering
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• v.23 no.6
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• pp.534-538
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• 2012

$Na^+$-beta-alumina solid electrolyte was synthesized by solid state reaction using $Li_2O$ and MgO as a phase stabilizer, and the effect of stabilizers on the phase formation and sintering density was investigated. In order to determine the phase fraction according to the synthesizing temperature, the molar ratio of [$Na_2O$] : [$Al_2O_3$] was fixed at 1 : 5, and calcination was conducted at temperatures between $1200{\sim}1500^{\circ}C$ for 2 h. In the $Li_2O$-$Na_2O$-$Al_2O_3$ ternary system, ${\beta}^{{\prime}{\prime}}$-alumina phase fraction considerably increased by the secondary phase transition at $1500^{\circ}C$, whereas it maintained similarly in the MgO-$Na_2O$-$Al_2O_3$ system. Additionally, the disc-type specimens of $Na^+$-beta-alumina were sintered at the temperature between $1550{\sim}1650^{\circ}C$ for 30 min, and relative sintering densities, phase changes, and microstructures were analyzed. In case of $Li_2O$-stabilized $Na^+$-beta-alumina, ${\beta}^{{\prime}{\prime}}$-phase fraction and relative density of specimen sintered at $1600^{\circ}C$ were 94.7% and 98%, respectively. Relative density of MgO-stabilized $Na^+$-beta-alumina increased with a rise in sintering temperature.

• Applied Chemistry for Engineering
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• v.33 no.2
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• pp.151-158
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• 2022

In this paper, parameter characteristics such as pH effect, isotherm, kinetic and thermodynamic parameters and competitive adsorption of dyes including malachite green (MG), direct red 81 (DR 81) and thioflavin S (TS), which have different functional groups, being adsorbed onto activated carbon were investigated. Langmuir, Freundlich and Temkin isotherm models were employed to find the adsorption mechanism. Effectiveness of adsorption treatment of three dyes by activated carbon were confirmed by the Langmuir dimensionless separation factor. The mechanism was found to be a physical adsorption which can be verified through the adsorption heat calculated by Temkin equation. The adsorption kinetics followed the pseudo second order and the rate limiting step was intra-particle diffusion. The positive enthalpy and entropy changes showed an endothermic reaction and increased disorder via adsorption at the S-L interface, respectively. For each dye molecule, negative Gibbs free energy increased with the temperature, which means that the process is spontaneous. In the binary component system, it was found that the same functional groups of the dye could interfere with the mutual adsorption, and different functional groups did not significantly affect the adsorption. In the ternary component system, the adsorption for MG lowered a bit, likely to be disturbed by the other dyes meanwhile DR 81 and TS were to be positively affected by the presence of MG, thus resulting in much higher adsorption.

• Applied Chemistry for Engineering
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• v.16 no.5
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• pp.664-671
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• 2005

In this study, the effect of sosurfactant on microemulsion phase behavior was investigated in ternary systems containing alkyl ethoxylates nonionic surfactant, water and d-limonene. The addition of a cosurfactant produced a microemulsion phase over a wide range of temperature and promoted formation of a microemulsion phase at lower temperatures. In particular, small amounts of n-propanol, as a cosurfactant, were found to be the most effective in extending a microemulsion phase region over a wide range of temperature. Temperature sensitivity of a nonionic surfactant system was effectively relieved by addition of the anionic surfactant sodium dodecyl sulfate. And the formation of one phase microemulsion was not affected by pH, hardness concentration and addition of an antioxidation agent. The cleaner candidates were determined from microemulsion phase behavior study, and their cleaning efficiency was tested using a dipping method. All the cleaner candidates selected during this study showed excellent removal efficiency for abietic acid over a temperature range from 30 to $40^{\circ}C$ presumably due to a decrease in interfacial tension.