• Coupled systems mechanics
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• v.10 no.2
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• pp.103-121
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• 2021

The present research deals with the investigation of the effect of hall current in an orthotropic magneto-thermoelastic medium with two temperature in the context of multi-phase-lag heat transfer due to thermomechanical sources. The bounding surface is subjected to linearly distributed and concentrated loads(mechanical and thermal source).Laplace and Fourier transform techniques are used to solve the problem. The expressions for displacement components,stress components and conductive temperature are derived in transformed domain and furtherin physical domain with the help of numerical inversion techniques. The effect ofrotation and hall parameter hasshown with the help of graphs.

• Structural Engineering and Mechanics
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• v.77 no.3
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• pp.315-327
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• 2021

Here, in this research we have studied a two dimensional problem in a homogeneous orthotropic magneto-thermoelastic medium with higher order dual-phase-lag heat transfer with combined effects of rotation and hall current in generalized thermoelasticity due to time harmonic sources. As an application the bounding surface is subjected to uniformly distributed and concentrated loads (mechanical and thermal source). Fourier transform technique is used to solve the problem. The expressions for displacement components, stress components and temperature change are derived in frequency domain. Numerical inversion technique has been used to obtain the results in physical domain. The effect of frequency has been depicted with the help of graphs.

• Food Science and Biotechnology
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• v.16 no.2
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• pp.183-186
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• 2007

The type of mixed gel network of $\kappa$-carrageenan/agar was determined by applying rheological principles. Apparent Young's modulus of the mixed gels was mathematically analyzed with (a) simply adding the moduli of two component gels, (b) phase-separated type's upper and lower bound models, (c) interpenetrating type's logarithmic model. The experimental data fitted the estimates from the operation (a). Whereas, as for the models (b), the experimental values in the agar-rich region fitted the estimates of the upper bound model, but in the $\kappa$-carrageenan-rich region slightly deviated from those of the lower bound model. It reflected an evidence of a phase-separated type, although it was not typical, that there must be data good-fit in the agar-rich and $\kappa$-carrageenan-rich regions with the upper and lower bound models, respectively. Experimental values disagreed with estimates of the model (c). Gel time was analyzed to evince the phase-separated type. As agar concentrations increased at a fixed amount of $\kappa$-carrageenan, gel time gradually decreased and then sharply increased and decreased again. The pattern of such change in gel time also represented a typical behavior of phase-separated type's mixed gels.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.37 no.1
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• pp.1-21
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• 2011

This review describes several kinds of emulsification methods for nanoemulsions and the application of nanoemulsions. Nanoemulsion droplet sizes fall typically in the range of 20 ~200 nm and show narrow size distributions. Although most of the publications on either oil-in-water (O/W) or water-in-oil (W/O) nanoemulsions have reported their formation by dispersion or high-energy emulsification methods, an increased interest is observed in the study of nano-emulsion formation by condensation or low-energy emulsification methods based on the phase transitions that take place during the emulsification process. Phase behaviour studies have shown that the size of the droplets is governed by the surfactant phase structure (bicontinuous microemulsion or lamellar) at the inversion point induced by either temperature or composition. Studies on nanoemulsion formation by the phase inversion temperature (PIT) method have shown a relation between minimum droplet size and complete solubilization of the oil in a microemulsion bicontinuous phase independently of whether the initial phase equilibrium is single or multiphase. Due to their small droplet size nanoemulsions possess stability against sedimentation or creaming with Ostwald ripening forming the main mechanism of nanoemulsion breakdown. An application of nanoemulsions is the preparation of nanoparticles using a polymerizable monomer as the disperse phase where nanoemulsion droplets act as nanoreactors, cosmetics and controlled drug delivery. In this review, we mainly focus on the cosmetics.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.9
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• pp.1037-1044
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• 2010

In this paper, a new size-reduced, wideband ring-hybrid coupler is presented, and a design of a planar single-balanced doubler using the ring-hybrid is shown. This ring-hybrid coupler employs a pair of ultra-wideband transitions for phase inversion, which consists of in-phase and out of-phase transitions providing a good amplitude and phase balances for wide frequency ranges. The implemented ring-hybrid is 65 % smaller than conventional ring-hybrids, and provides 92.5 % and 81.3 % bandwidth at $\sum$ and $\Delta$ ports, respectively. Thanks to good amplitude and phase balances over wide bandwidth, the ring-hybrid can be applied to implement various balanced components. The implemented single-balanced doubler utilizing the ring-hybrid exhibits typical conversion loss of 10.5 dB for the output frequency range of 4~12 GHz with fundamental suppression level of 30 dB. The performance was also well-predicted with the nonlinear circuit simulation.

• Journal of the Korean Applied Science and Technology
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• v.34 no.2
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• pp.225-235
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• 2017

In this study, we investigated the effect on the increase of In vitro skin permeation experiments and In-vivo skin whitening efficacy using a O/W nanoemulsion produced via PIC(Phase Inversion Composition) with 1,3-di(pentyloxyl)benzene. skin permeation experiments of RS-nanoemulsion formulated with selected condition was evaluated compared to mineral oil containing 1,3-di(pentyloxyl)benzene and normal O/W type RS-emulsion. Compared to mineral oil with 1,3-di(pentyloxyl)benzene and RS-emulsion. RS-Nanoemulsion has a statistically significant high percutaneous absorption in terms of index substance, which is 1,3-di(pentyloxyl)benzene. In vivo test were prepared in the system of O/W cream containing RS-nanoemulsion. There was no adverse reactions in both samples. After 8 weeks, the subjects was evaluated by a dermatologist's scoring and Chromameter. In conclusion, the testing product showed statistically improvement (p<0.05) compared to the controlled product and proved its whitening efficacy.

• Membrane Journal
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• v.26 no.4
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• pp.281-290
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• 2016

Thin film composite (TFC) polyamide membranes were prepared on polysulfone (PSF) supports for forward osmosis (FO) applications. To understand the influence of polarity and porosity of support layer on the formation of polyamide structure and the final FO performance, clathochelate metal complex (MC) contained PSF supports were prepared via the phase inversion process from various PSF casting solutions containing 0.1-0.5 wt% of MC in dimethyl formamide (DMF) solvent (18 wt%). A crosslinked aromatic polyamide layer was then fabricated on top of each support to form a TFC membrane. For the porous PSF supports prepared with relatively low concentration casting solutions (12 wt%), the PET film was removed after phase inversion and crosslinked aromatic polyamide layer was then fabricated. The tested sample from PSF (18 wt%)/MC (0.5 wt%) casting solution presented outstanding FO performance, almost similar water flux (9.99 LMH) with lower reverse salt flux (RSF, 0.77 GMH) compared to commercial HTI FO membrane(10.97 LMH of flux and 2.2 GMH of RSF). By addition of MC in casting solution, the thickness of the active layer in FO membranes was reduced, however, the increased RSF value was obtained.

• Membrane and Water Treatment
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• v.6 no.5
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• pp.365-378
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• 2015

Herein, the preparation of anion exchange membrane (AEM) from brominated poly(2,6-dimethyl 1,6-phenylene oxide) BPPO and dimethylaniline (DMA) by phase-inversion process is reported. Anion exchange membranes (AEMs) are prepared by varying the DMA contents. Prepared AEMs show high thermal stability, water uptake (WR) around 202% to 226%, dimensional change ratios of 1.5% to 2.6% and ion exchange capacities (IECs) of 0.34 mmol/g to 0.82 mmol/g with contact angle of $59.18^{\circ}$ to $65.15^{\circ}$. These membranes are porous in nature as confirmed by SEM observation. The porous property of membranes are important as it could reduce the resistance of transportation of ions across the membranes. They have been used in diffusion dialysis (DD) process for recovery of hydrochloric acid (HCl) from the mixture of HCl and ferrous chloride ($FeCl_2$). Presence of $-N+(CH_3)_2C_6H_5Br^-$ as a functional group in membrane matrix facilitates its applications in DD process. The dialysis coefficients of hydrochloric acid ($U_H$) of the membranes are in range of 0.0016 m/h to 0.14 m/h and the separation factors (S) are in range of 2.09 to 7.32 in the $HCl/FeCl_2$ system at room temperature. The porous membrane structure and presence of amine functional group are responsible for the mechanism of diffusion dialysis (DD).

• Applied Chemistry for Engineering
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• v.19 no.2
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• pp.185-190
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• 2008

In order to increase the surface area of electrodes for electrosorption, porous carbon electrodes were fabricated by a wet phase inversion method. A carbon slurry consisting of a mixture of activated carbon powder (ACP), polyvinylidene fluoride (PVdF), and N-methyl-2-pyrrolidone (NMP) as a solvent was cast directly on a graphite sheet. The cast film was then immersed in pure water for phase inversion. The physical and electrochemical properties of the electrodes were investigated using scanning electron microscopy (SEM), porosimetry, and cyclic voltammetry. The SEM images verified that the pores of various sizes were formed uniformly on the electrode surface. The average pore sizes determined for the electrodes fabricated with various NMP contents ranged from 64.2 to 82.4 nm and the size increased as the NMP content increased. All of the voltammograms showed a typical behavior of charging and discharging characteristic at the electric double layer. The electrical capacitance ranged from 3.88 to $5.87F/cm^2$ depending on the NMP contents, and the electrical capacitance increased as the solvent content decreased. The experimental results showed that the solvent content is an important variable controlling pore size and ultimately the capacitance of the electrode.

• Membrane Journal
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• v.16 no.4
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• pp.303-312
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• 2006

The asymmetric hybrid membranes of polyethersulfone (PES) and $ZrO_2$ nanoparticles were prepared via new one-step procedure combining simultaneously the phase-inversion method and the sol-gel technique. The optimum contents of $Zr(PrO)_4\;and\;HNO_3$ catalyst were determined by the adsorption experiments of phosphate anion onto the resulting hybrid membranes. The maximum adsorption of phosphate anion is obtained at the conditions of 0.15 mL $Zr(PrO)_4$ addition per 1 mL PES and 30 mL $HNO_3$ addition per 1 mL $Zr(PrO)_4$. Variation of morphology, performance and incorporated $ZrO_2$ amount of the resulting hybrid membranes were discussed and determined using SEM, pure water flux, TGA, ICP, XRD and contact angle measurements. Increasing $Zr(PrO)_4$ addition into casting solution, pure water flux is increased and $ZrO_2$ amount in the hybrid membrane is maximized at the conditions 0.15 mL $Zr(PrO)_4$ addition per 1 mL PES. The prephosphatation of PES-$ZrO_2$ hybrid membrane was studied to modify the surface characteristics of membrane. Ultrafiltration of bovine serum albumin (BSA) solution was performed in a dead-end cell using both a bare (non-phosphated) and a phosphated hybrid membrane. It is revealed that both the permeate flux and BSA rejection were increased as about 40% by prephosphatation of hybrid membrane. These results may be explained on the basis of the increase of membrane hydrophilicity, which was determined from contact angle measurements.