Korean Journal of Chemical Engineering (v.25, #2)

A numerical study on drying of porous media by Nima Amanifard; Akbar Khodaparast Haghi (191-198).
In this study, two-dimensional conjugate heat and mass transfer in porous body and drying air during the drying process were numerically investigated by finite volume (FV) method, which guarantees the conservation of mass, momentum and the energy during the numerical solution. The full NS-equations (including buoyancy terms), energy equation and concentration equation are considered for external flow and for porous field coupled energy and moisture transfer equations are used. The numerically captured curve shows the same behavior of the drying process. Drying flow velocity shows proportional effect on moisture removal rate with a factor between $$ { aise0.5exhbox{$scriptstyle 1$} kern-0.1em/kern-0.15em lower0.25exhbox{$scriptstyle 4$}} $$ and $$ { aise0.5exhbox{$scriptstyle 1$} kern-0.1em/kern-0.15em lower0.25exhbox{$scriptstyle 5$}} $$ in Reynolds range of 50 to 1,000. Also, buoyancy forces have an effect on flow streamlines, the distribution of vapor concentration, moisture profile, and considerably increase drying rate. This increment was investigated in Reynolds number range of 50 to 1,000, and its minimum value was found in a Reynolds number of 1,000, which was about 15 percent.
Keywords: Drying Process; Forced Convection; Mixed Convection; Numerical Study; Porous Media

Onset of convection in a porous mush during binary solidification by In Gook Hwang; Chang Kyun Choi (199-202).
The onset of convection in a mushy layer during solidification of a binary melt is investigated by using the propagation theory we have developed. The critical conditions for the mushy-layer-mode of instability are obtained numerically for aqueous ammonium chloride solution. The mush thickness at the onset of convection is predicted as a function of the solution viscosity and compared with the experimental data. The onset time of the mushy-layer-mode convection has a minimum point with varying the superheat. When the superheat is large, the mushy layer grows slowly and a long time is required for the onset of convection.
Keywords: Onset of Convection; Solidification; Mush; Propagation Theory

A new multivariate statistical model updating by using a recursive state space model updating based on CVA is proposed. The CVA-based monitoring techniques have been researched to detect and isolate process abnormalities in dynamic processes. Two monitoring indices are defined for fault detection, and a state space model updating procedure is developed by using mean, covariance, and correlation updating based on forgetting factor as well as the recursive Cholesky factor updating. To adjust forgetting factors according to variation of process state, the forgetting factor updating criteria are introduced. The proposed method is applied to benchmark models of a continuous stirred tank reactor with a first order reaction and the Tennessee Eastman process (TEP) under transient and time-varying operating conditions. Through the simulation results, we expect that the proposed approach can be applied to time-varying and dynamic processes under transient state.
Keywords: Adaptive Monitoring; State Space Model; Canonical Variate Analysis

A two-phase flow configuration in which the gas phase flows upwards while the liquid phase flows downwards is referred to as a counter-current flow pattern. This flow configuration cannot be preserved if any flow rate exceeds a criterion known as the counter-current flow limitation (CCFL) or flooding. Since the CCFL is important to chemical engineers, it has long been studied via experimental and analytical approaches. Most of the previous CCFL experiments in annular channels have been carried out with a small diameter annulus and large gap-to-diameter ratio annulus. The present experiment examines the CCFL in narrow annular channels having gap sizes of 1, 2, 3, and 5 mm. The outer diameter of the annular passage is 500 mm. At a gap size of 1 mm, it was visually observed that a CCFL locally occurred in some region of the periphery while the other region remained in a counter-current flow configuration. The region under partial CCFL condition expanded with an increase in the air flow rate, finally reaching a global CCFL. The air flow rate for the global CCFL was roughly 15% larger than that for initiation of a partial CCFL. This difference in air flow rate between the initiation of a partial CCFL and the global CCFL was reduced as the gap size increased. When the gap size was 5 mm, the partial CCFL was not observed, but onset of flooding led to a global CCFL. Because of the existence of a transient period, the CCFL was experimentally defined as the situation where net water accumulation is sustained. The measured CCFL data are presented in the form of a Wallis’ type correlation. Two length scales, hydraulic diameter and average circumference, were examined as the characteristic length scale. The average circumference appeared to better fit the experimental data, including results reported elsewhere. A new correlation using the average circumference as the characteristic length scale is suggested based on the experimental measurements of the present work and previous reports.
Keywords: Flooding; CCFL; Annular Narrow Gap; Counter-current Flow; Characteristic Length

3D CFD analysis of the hydrogen releases and dispersion around storage facilities by Jin-Woo Hwang; Do-Young Yoon; Kil-Ho Choi; Younghun Kim; Lae Hyun Kim (217-222).
Unexpected hazards often arise from hydrogen storage and distribution facilities, and latent dangers induced by handling of hydrogen. This paper represents the results of CFD (computational fluid dynamics) modeling of hydrogen releases and dispersion at model storage facilities with simple geometries. Numerical results for model storage facility were compared with the reported data on the hydrogen dispersion. In addition, the hydrogen concentration in a real industrial environment, such as in the hydrogen energy station (HES), was estimated with 3D CFD modeling. The risk assessment was achieved under hypothetical hydrogen leakage scenarios.
Keywords: Hydrogen Release; 3D CFD; Risk Assessment; Hydrogen Energy Station

High temperature desulfurization over nano-scale high surface area ceria for application in SOFC by Rajesh Shivanahalli Kempegowda; Navadol Laosiripojana; Suttichai Assabumrungrat (223-230).
In the present work, suitable absorbent material for high temperature desulfurization was investigated in order to apply internally in solid oxide fuel cells (SOFC). It was found that nano-scale high surface area CeO2 has useful desulfurization activity and enables efficient removal of H2S from feed gas between 500 to 850°C. In this range of temperature, compared to the conventional low surface area CeO2, 80–85% of H2S was removed by nano-scale high surface area CeO2, whereas only 30–32% of H2S was removed by conventional low surface area CeO2. According to the XRD studies, the product formed after desulfurization over nano-scale high surface area CeO2 was Ce2O2S. EDS mapping also suggested the uniform distribution of sulfur on the surface of CeO2. Regeneration experiments were then conducted by temperature programmed oxidation (TPO) experiment. Ce2O2S can be recovered to CeO2 after exposure in the oxidation condition at temperature above 600°C. It should be noted that SO2 is the product from this regeneration process. According to the SEM/EDS and XRD measurements, all Ce2O2S forming is converted to CeO2 after oxidative regeneration. As the final step, a deactivation model considering the concentration and temperature dependencies on the desulfurization activity of CeO2 was applied and the experimental results were fitted in this model for later application in the SOFC model.
Keywords: Desulfurization; SOFC; CeO2 ; Deactivation Model

Immobilization of H3PMo12O40 catalyst on the nitrogen-containing mesoporous carbon and its application to the vapor-phase 2-propanol conversion reaction by Heesoo Kim; Ji Chul Jung; Dong Ryul Park; Joohyung Lee; Kyung Min Cho; Sunyoung Park; Sang Hee Lee; In Kyu Song (231-235).
Nitrogen-containing mesoporous carbon (N-MC) with high surface area (=1,115 m2/g) and large pore volume (=1.18 cm3/g) was synthesized by a templating method. The surface of N-MC was then modified to form a positive charge, and thus, to provide sites for the immobilization of [PMo12O40]3−. By taking advantage of the overall negative charge of [PMo12O40]3−, H3PMo12O40 (PMo12) was chemically immobilized on the N-MC support as a charge matching component. It was found that the PMo12/N-MC still retained relatively high surface area (=687 m2/g) and large pore volume (=0.67 cm3/g) even after the immobilization of PMo12. It was also revealed that PMo12 species were finely and molecularly dispersed on the N-MC support via chemical immobilization. In the vapor-phase 2-propanol conversion reaction, the PMo12/N-MC showed a higher conversion than the unsupported PMo12. Furthermore, the PMo12/N-MC showed an enhanced oxidation catalytic activity and a suppressed acid catalytic activity compared to the unsupported PMo12. This catalytic behavior of PMo12/N-MC was due to the molecular dispersion of PMo12 on the N-MC support formed via chemical immobilization by sacrificing the proton.
Keywords: Heteropolyacid Catalyst; Immobilization; Nitrogen-containing Mesoporous Carbon; 2-Propanol Conversion Reaction; Oxidation Catalysis

Effect of support on hydrogen production by auto-thermal reforming of ethanol over supported nickel catalysts by Min Hye Youn; Jeong Gil Seo; Kyung Min Cho; Ji Chul Jung; Heesoo Kim; Kyung Won La; Dong Ryul Park; Sunyoung Park; Sang Hee Lee; In Kyu Song (236-238).
Nickel catalysts supported on various supports such as ZnO, MgO, ZrO2, TiO2, and Al2O3 were prepared by an impregnation method to investigate the effect of support on catalytic performance in hydrogen production by auto-thermal reforming of ethanol. Among the supported catalysts, the Ni/ZrO2 and Ni/TiO2 catalysts showed better catalytic performance than the other catalysts. The electronic structure of nickel species supported on ZrO2 and TiO2 was favorably modified for the reaction, and thus, the reducibility of nickel species supported on ZrO2 and TiO2 was increased due to the weak interaction between nickel and support. On the other hand, the Ni/MgO and Ni/ZnO catalysts exhibited poor catalytic performance in the auto-thermal reforming of ethanol due to the formation of a solid solution phase.
Keywords: Auto-thermal Reforming of Ethanol; Hydrogen Production; Effect of Support; Supported Nickel Catalyst

Deactivation of barium oxide-based NO x storage and reduction catalyst by hydrothermal treatment by Ji Won Park; Se Min Park; Young San Yoo; Hyun-Sik Han; Gon Seo (239-244).
The deactivation of a barium oxide-based NO x storage and reduction (NSR) catalyst with hydrothermal treatment was studied by treating it with 10 vol% water vapor diluted in nitrogen at 850°C. XRD, XPS, SEM, IR of CO adsorption, and the N2 adsorption was used to investigate the physical and chemical changes of the NSR catalyst caused by the hydrothermal treatment. The 12 h hydrothermal treatment decreased its NO2 storage capacity by 20%. However, the hydrothermal treatment significantly decreased its ability to reduce the stored NO2. The formation of an inactive phase consisting of platinum and aluminum is believed to be the cause of the severe deactivation of the NSR catalyst.
Keywords: NO x Storage and Reduction (NSR); Barium Oxide; Deactivation; Hydrothermal Treatment

Electrochemical impedance spectroscopy (EIS) was used to investigate the influence of several parameters on the performance of PEMFC. The applied frequency was in the range of 50 mHz–10 kHz. The experiment was designed by using a 2 k factorial design to identify the effects of various parameters including cell voltage, flow rates of gaseous fuels and cell temperature at the saturated humidification in anode and 60% relative humidity cathode. The results indicated that the cell temperature, cell voltage and interactions of cell voltage, flow rate of H2 and O2 had a significant effect on the cell performance. In addition, the flow rate of O2 had a strong effect on the ohmic resistance and the charge transfer resistance in the system. Models describing the relationship between previous parameters and ohmic resistance, charge transfer resistance and capacitance were also developed.
Keywords: Electrochemical Impedance Spectroscopy; Membrane Electrode Assembly; PEM Fuel Cell; Relative Humidification; Factorial Design

Removal characteristics of metal cations and their mixtures using micellar-enhanced ultrafiltration by Hojeong Kim; Kitae Baek; Bo-Kyong Kim; Hyun-Jae Shin; Ji-Won Yang (253-258).
Divalent ions were removed by ultrafiltration of anionic surfactant solution and the removal characteristics in single and mixed systems were investigated. The removal efficiency was >95% when the ratio of sodium dodecyl sulfate (SDS) to metal ions (S/M ratio) was >10. In single metal systems, the removal efficiency of each metal ion was almost the same. In the mixture, however, there was slight difference (ca. 1–2%) of removal efficiency and the order was Cd2+>Cu2+>Co2+≈Zn2+. As S/M ratio increased, the difference in removal efficiency diminished. To explain the difference of removal efficiency in a mixture, complexation of divalent metal ion with counterion was considered. The distribution of complexed form of each metal ion was calculated, but it did not coincide with the experimental results. Further research will be necessary for a clear explanation.
Keywords: Heavy Metal; Micelle; Sodium Dodecyl Sulfate (SDS); Ultrafiltration

Performance evaluation and mathematical modelling of granular activated carbon biofiltration in wastewater treatment by Thi To Loan Hoang; Saravanamuthu Vigneswaran; Huu Hao Ngo; Jaya Kandasamy; Wang Geun Shim; Dungananda Singh Chaudhary; Pavan Gotety; Paul Peiris (259-267).
Biological filtration is an effective technique for removing organic matter from wastewater. The performance of a biofilter can be influenced by a range of operational conditions. In this study the performance of biofilters was investigated for the influence of filter media depth, influent concentrations, filtrations rates and backwashing. The results show that performance of GAC filters decreased with shallower filter bed depths. In addition, the GAC performed better at lower influent concentration and lower filtration rates. The daily backwash adopted to avoid the physical clogging of the biofilter did not have any significant effect on the organic removal efficiency of the filter. The concentration, activity and characteristics of the biomass are quantified and described. A mathematical model was developed to simulate the organic removal of the GAC biofiltration system. The performance of the GAC filter under different influent organic concentration levels, filtration rates and filter bed depths was adequately simulated by the mathematical model developed for this study.
Keywords: Biofilter; GAC; Organics; Biomass; Mathematical Modelling

Solvent-free magnesium alanates were prepared by a mechanochemical metathesis reaction method (ball milling method) with a variation of milling time. For the purpose of comparison, magnesium alanate was also prepared by metathesis reaction method in the presence of diethyl ether. The formation of magnesium alanate (Mg(AlH4)2) and magnesium alanate-diethyl ether (Mg(AlH4)2·Et2O) adduct was confirmed by XRD measurements. In both magnesium alanates, hydrogen evolution occurred in the first step decomposition. The starting temperature for hydrogen evolution of the solvent-free magnesium alanates decreased with increasing milling time, whereas the amount of hydrogen evolution of the solvent-free magnesium alanates increased with increasing milling time. The maximum amount of hydrogen evolution of the Mg(AlH4)2·Et2O adduct was slightly larger than that of the solvent-free Mg(AlH4)2, but the starting temperature for hydrogen evolution of the Mg(AlH4)2·Et2O adduct was much higher than that of the solvent-free Mg(AlH4)2. The addition of a small amount of titanium to the solvent-free Mg(AlH4)2 greatly reduced the hydrogen evolution temperature of titanium-doped Mg(AlH4)2. However, the maximum amount of hydrogen evolution of the titanium-doped Mg(AlH4)2 was smaller than that of the solvent-free Mg(AlH4)2.
Keywords: Magnesium Alanate; Mechanochemical Metathesis Reaction; Thermal Decomposition; Hydrogen Storage

Excess Gibbs free energy of butyl acetate with cyclohexane and aromatic hydrocarbons at 308.15K by Sanjeev Maken; Naveen Verma; Ankur Gaur; Ho-Jun Song; Krishan Chander Singh; Jin-Won Park (273-278).
Molar excess Gibbs free energies of mixing (C E ) for butyl acetate+cyclohexane or benzene or toluene or o- or m- or p-xylene were calculated by using Barker’s method from the measured vapor pressure data by static method at 308.15±0.01 K over the entire composition range. The G E values for the binary mixtures containing cyclohexane or benzene are positive; while these are negative for toluene, o-, m- and p-xylene system over the whole composition range. The G E values of an equimolar mixture for these systems vary in the order: cyclohexane>benzene>o-xylene>m-xylene>p-xylene>toluene. The G E values for these systems were also calculated by Sanchez and Lacome theory using the previously published excess enthalpy and excess volume data. It is found that while values of G E from Sanchez and Lacombe theory are in reasonably good agreement with those calculated by Barker method for m-xylene and p-xylene mixtures, agreement is very poor for other systems although they predict the sign of G E data except in the case of mixtures containing benzene.
Keywords: Gibbs Free Energy; Vapor Liquid Equilibrium; Static Method; Butyl Acetate; Aromatic Hydrocarbon; Barker’s Method; Sanchez and Lacombe Theory

Characteristics of absorption and regeneration of carbon dioxide in aqueous 2-amino-2-methyl-1-propanol/ammonia solutions by Dong-Hyeon Lee; Won-Joon Choi; Seung-Jae Moon; Soo-Ho Ha; Im-Gyung Kim; Kwang-Joong Oh (279-284).
In this study, the removal efficiency, absorption amount, and loading value of CO2 into aqueous blended 2-amino-2-methyl-1-propanol (AMP)/ammonia (NH3) solutions were measured by using the absorption and regeneration continual process. The effect of adding NH3 to enhance absorption characteristics of AMP was investigated. The performance was evaluated under various operating conditions. As a result, the method of blending AMP and NH3 was not adequate because of a problem with scale formation. Consequently, NH3 of 1, 3, 5, and 7 wt% was added to 30 wt% AMP. Of these additions, 5 wt% NH3 was the optimum concentration because the CO2 removal efficiency and absorption amount were almost 100% and 2.17 kg CO2/kg absorbent, respectively. Also, the scale problem was almost absent. As the regenerator temperature varied from 80–110 °C, the loading of rich amine was almost constant, but the loading of lean amine was decreased as the regenerator temperature increased. Thus, the optimum regenerator temperature was 110 °C in this experiment.
Keywords: Carbon Dioxide; 2-Amino-2-methyl-1-propanol; Ammonia; Absorption; Regeneration

The enrichment of loxoprofen enantiomer by 6-columns simulated moving bed chromatography by Tae Ho Yoon; Eun Lee; Jong Min Kim; Woo-Sik Kim; In-Ho Kim (285-290).
Simulated moving bed (SMB) chromatography is very useful for the separation of binary systems such as chiral compounds. Because loxoprofen racemate has four enantiomers owing to its two chiral centers, to gain pure enantiomer it is impossible with only one step. To apply enrichment of loxoprofen using SMB, extract and raffinate should be separated as a binary mixture. In order to enrich loxoprofen racemate as binary mixture among four mixtures and to characterize its enantiomer, we performed experiments with two types of columns. When TBB® column was used as CSP, the mixture of (1′R,2S) and (1′S,2S) forms was eluted as a raffinate and that of (1′R,2R) and (1′S,2R) forms was discharged as a extract under linear adsorption isotherm range. When the feed flow rates were 0.1 and 0.3 mL/min, purities of raffinate and extract were 98 and 95%, respectively. In this case, productivity of raffinate was 7.81 g/h·g-CSP and that of extract was 6.95 g/h·g-CSP
Keywords: Loxoprofen; SMB; Chiral Enrichment; TBB® Column; (1R,2S) & (1S,2S)

Enhanced stability of Candida antarctica lipase B in ionic liquids by Sung Ho Ha; Sang Hyun Lee; Dung Thanh Dang; Min Sik Kwon; Woo-Jin Chang; Yong Jae Yu; Il Suk Byun; Yoon-Mo Koo (291-294).
The activity and stability of lipase from Candida antarctica were investigated in the kinetic resolution of (R,S)-1-phenylethanol with vinyl acetate using ionic liquids (ILs) as reaction media. Among ILs tested, the highest activity of lipase was observed in [Edmim][Tf2N]. In hydrophobic ILs such as [Edmim][Tf2N], [Emim][Tf2N] and [Pmim] [PF6], lipase could retain its activity after 5 times reuse, while the activity of lipase in hydrophilic ILs and organic solvents was drastically decreased. The activities of lipase in [Edmim][Tf2N], [Emim][Tf2N] and [Pmim][PF6] were also well maintained after 1 day incubation at 80 °C. The lipase suspended in [Edmim][Tf2N] could be successfully reused 6 times without loss of activity.
Keywords: Ionic Liquid; Lipase; (R,S)-1-Phenylethanol; Reuse; Stability

Effect of mesenchymal cells on human hair growth and death by Bo-Young Yoo; Young-Kwon Seo; Hee-Hoon Yoon; Youn-Ho Shin; Kye-Yong Song; Jung-Keug Park (295-301).
Animals have typically been used in efficacy tests, but there are a number of dissimilarities between humans and animals. To overcome the problems associated with animal testing, a model which is reproduced in vitro with longterm culture with cell growth with in vivo activity must be developed. We made a gel-type dermal equivalent (DE) that contained dermal papilla cells (DPCs) or dermal sheath cells (DSCs) isolated from human hair bulbs in order to mimic human scalp tissue. Hair follicles were organ-cultured on DE containing DPCs or DSCs. The DE used for organ culture was a reconstructed 3-dimensional contraction of collagen gel, and the cell density of the DE did not affect the increase in hair length. We tested the effects of cell types in DE on increases in hair length, and the results showed a large increase in hair length and long-term viability in the air-liquid interface culture on DE containing DSCs. We compared the submerged culture with the hair air-liquid interface culture on DE using immunohistochemical staining, and found that the hair follicles that were air-liquid interface cultured on DE maintained the growth phase (anagen) for a longer period of time than the hair follicles that were submerged. Since the hair follicles were cultured under an air-liquid interface condition, the increase in hair length was a reflection of the epithelial cell growth that resulted from the improved oxygen supply and paracrine factors secreted from hair origin cells.
Keywords: Hair Growth; Mesenchymal Cell; Organ Culture

Kinetic studies of hemicellulose hydrolysis of corn stover at atmospheric pressure by Xuebin Lu; Yimin Zhang; Ying Liang; Jing Yang; Shuting Zhang; Eiji Suzuki (302-307).
The object of this work was to study the xylose production by hydrolysis of corn stover with diluted sulfuric acid at 100 °C. Several concentrations of H2SO4 (2%, 4% and 6% w/w) and reaction time (0–300 min) were evaluated. Kinetic parameters of mathematical models for predicting the concentrations of xylose, glucose and furfural in the hydrolysates were found. Optimal conditions for hydrolysis were 5.5% H2SO4 at 100 °C for 60 min; under these conditions, 86.7% of xylose yield and 2.82 g/g selectivity were attained, leading to liquors containing up to 18.73 g/l xylose, 6.64 g/l glucose and 0.63 g/l furfural. The models could be successfully used to predict the concentrations of xylose, glucose and furfural within 0–300 min under experimental acid concentrations. Furthermore, the hydrolysis process of corn stover using dilute acid could be conceived as the first stage of an integrated strategy for corn stover utilization.
Keywords: Hydrolysis; Corn Stover; Xylose; Glucose; Kinetics

Differential expression of liver proteins in streptozotocin-induced diabetic rats in response to hypoglycemic mushroom polysaccharides by Hye Jin Hwang; Sang Woo Kim; Yu Mi Baek; Sung Hak Lee; Hee Sun Hwang; Suresh G. Kumar; Md. Atiar Rahman; Jong Won Yun (308-322).
We investigated the influence of hypoglycemic fungal extracellular polysaccharides (EPS) on the differential expression of liver proteins in streptozotocin (STZ)-induced diabetic rats. The results of diabetic study revealed that orally administrated EPS exhibited an excellent hypoglycemic effect, lowering the average plasma glucose level in EPS-fed rats to 55.1% with enhanced glucose tolerance. In the next step, we analyzed the differential expression patterns of rat liver proteins from each group to discover potent candidates for diabetes-associated proteins. 34 proteins were upregulated and 35 proteins were downregulated upon diabetes induction. Surprisingly, the altered levels of most proteins in the diabetic group were fully or partially restored to those of the non-diabetic control group by EPS treatment. Although the molecular basis of protein modulation after EPS administration in diabetic rats was not verified, the results of the proteomic analysis provide impetus for further studies to identify reliable biomarkers for diabetic therapy.
Keywords: Diabetic Rat; Liver Proteome; Phellinus baumii ; Polysaccharides; Streptozotocin

Melting treatment of waste asbestos using mixture of hydrogen and oxygen produced from water electrolysis by Soon Young Min; Sanjeev Maken; Jin-Won Park; Ankur Gaur; Jang Soo Hyun (323-328).
In this study, we melted four types of waste asbestos containing material such as spread asbestos, plasterboard asbestos, slate asbestos and asbestos 99 wt%, in a melting furnace at 1,450–1,550 that uses a mixture of hydrogen and oxygen (Brown’s gas) as a fuel. More volatile components (CaO, K2O) are enriched in spread asbestos, plasterboard asbestos, and slate asbestos, while less volatile compounds (SiO2, Fe2O3, MgO) remain in asbestos 99%. Through basicity of raw materials, spread asbestos, plasterboard asbestos, and slate asbestos were found to have more alkalinity, and asbestos 99% was found more acidic. SEM and EDX results revealed that all raw materials had various kinds of asbestos fiber. Spread asbestos, plasterboard asbestos, and slate asbestos were considered as tremolite asbestos, whereas asbestos 99% was considered as chrysotile asbestos. It was further confirmed by SEM and XRD studies that all waste materials contained some crystalline structures which transformed into amorphous glassy structure on melting. Also, in case of added glass cullet during the melting of spread asbestos, it transformed the raw material into a perfect vitrified product having more glassy surface and amorphous in nature
Keywords: Waste Asbestos; Brown’s Gas; Basicity; Vitrification; Stabilization

Hierarchical Clustering (HC) technique is demonstratively applied to analyze the distribution and classification of essential-oil components in oil and dense (subcritical/supercritical) CO2 phases. For this purpose, relative-equilibrium-distribution data obtained for the 24 characteristic components of origanum-oil (Origanum Munituflorum) at 35, 45, 55 °C and 20–110 atm pressure range are used. With 24 components and 25 different pressure levels at three different temperatures, the total number of data points amounts to 600, which is large compared to other similar works, making the task of drawing of conclusions by visual inspection quite tedious. As demonstrated in this work, the use of HC technique facilitates the classification of the distribution of essential-oil components. HC-based classification analysis helps to reveal that the distributions of monoterpenes are the most sensitive to changes in temperature and pressure, and they are more soluble in CO2 especially in the supercritical region. At 35 °C, at higher pressures, due to high solvent density/power, almost all components show similar distributions in the CO2 and oil phases, indicating the loss of fractionation potential. Deterpenation by CO2 is more favorable at higher temperatures. Cophnetic correlation shows the significance level of data clustering. HC analysis proved to be a useful tool in classification of the components and in determination of component clusters in the dense-gas and liquid phases.
Keywords: Supercritical Carbon Dioxide; Essential Oil; Origanum Oil; Hierarchical Clustering; Dendrogram; Classification; Equilibrium Distribution

Typical methods for calculation of binary liquid-liquid equilibrium compositions such as surfactant systems need proper initial guesses and/or checking the sign of the second derivative of molar Gibbs energy change of mixing, ΔG. Eubank and Hall [1] have shown the equal area rule (EAR) applies to the composition derivative of the Gibbs energy of a binary system at fixed pressure and temperature. Methods based on EAR do not need to check the sign of the second derivative of ΔG because EAR is a necessary and sufficient condition for phase equilibrium. However, the algorithm proposed by Eubank and Hall needs a reasonable initial guess. Furthermore, it is not easy to apply the algorithm to activity coefficient models such as Non-Random Two Liquid (NRTL) because the first and second derivatives of ΔG as a function of composition have various shapes for some sets of NRTL parameters. In this work, we have developed an improved algorithm for calculation of binary liquid-liquid equilibrium compositions based on EAR considering the various shapes of NRTL model. This algorithm needs neither any initial guess nor checking the sign of the second derivative of ΔG.
Keywords: Binary Mixture; Liquid-liquid Equilibria (LLE); Equal Area Rule (EAR); NRTL; Algorithm

Fabrication of nontoxic natural dye from sappan wood by Dong-Kyu Lee; Dong-Hoe Cho; Jin-Hui Lee; Hun Yong Shin (354-358).
The use of natural dyes has attracted increasing worldwide attention as the carcinogenicity and environmental pollution problem of synthetic pigments are becomes a great concern. A nontoxic natural dye was fabricated from an extract from Caesalpinia Sappan (sappan wood). Oily natural dye for industrial application was made from extracted sappan wood by using a micro-emulsion method. The absorbance of the dye extracted from sappan wood by distillation was measured with an Ultraviolet/Visible spectrometer. The highest absorbance was obtained from the mordant containing 2 wt% Al. The emulsification conditions were controlled by changing the mixing ratios of TEOS (tetraethyl ortho-silicate), DC3225C (cyclomethicone and dimethicon copolyol) and extracted dye. A W/O (water in oil) type dye was obtained with a TEOS concentration ranging from 19.9 to 50.0 wt% when the DC3225C concentration was fixed to 10 wt%. The W/O type emulsion was verified by optical microscopy. The fabricated dye was applied to colored paper. The applicability of the nontoxic natural dye was verified by analyzing the heavy metals and color fastness of the colored paper.
Keywords: Natural Dye; Extraction; Mordant; W/O Type; Sappan Wood

Composite particles prepared by spray pyrolysis of aqueous solution of AgNO3 and Ni(NO3)2·6H2O with 10 vol%H2-N2 were characterized and compared with the particles similarly prepared from their pure nitrates. The composite particles were composed of metallic silver, nickel oxide or metallic nickel, depending on the condition, with no trace of alloy. The existence of nickel ions dispersed throughout the particles did not affect the rate of reduction to the highly reducible silver but retarded its subsequent crystal growth. On the other hand, both the reduction to nickel and its crystal growth were all retarded due to the existence of the more reducible silver ions. In addition to these, the incompatibility also increased the size of the composite particles from the corresponding single component particles and kept it almost constant with respect to the preparation temperature.
Keywords: Silver/nickel; Composite particles; Spray pyrolysis; Intraparticle properties; Reduction; Crystallization; Incompatibility

The photocatalytic activity of CVD grown films shows significant, non-linear (sigmoid-like) dependency on the film thickness. However, the photocatalytic activity of sol-gel grown film is almost independent of the film thickness. The specific surface area of sol-gel grown films is very small, regardless of the film thickness. Conversely, the specific surface area of CVD grown films indicates significant thickness dependency. The specific area and photocatalytic activity were found to show very similar dependencies on the film thickness.
Keywords: TiO2 Film; Chemical Vapor Deposition Method; Sol-Gel Method; Specific Surface Area; Photocatalytic Activity

Characteristics of Nylon 6 nanofilter for removing ultra fine particles by Gil Tae Kim; Young Chull Ahn; Jae Keun Lee (368-372).
Electrospinning is a fabrication process that uses an electric field to make polymer nanofibers. Nanofibers have a large specific surface area and a small pore size; these are good properties for filtration applications. In this paper, the filtration characteristics of a Nylon 6 nanofilter made by electrospun nanofibers are tested as a function of the fiber diameter. Nanofilter media with diameters in the range of 100–730 nm can be produced in optimized conditions. The pressure drop of a Nylon 6 nanofilter linearly increases with the increasing face velocity. An electrospun Nylon 6 filter (mean fiber diameter: 100 nm) shows a much lower pressure drop performance relative to the commercial HEPA filter media when the filtration efficiency of the Nylon 6 nanofilter and the HEPA filter are over 99.98% with test particles of 0.02–1.0 μm in diameter. The pressure drop at 5 cm/s of the face velocity is measured as 27 mmAq for the Nylon 6 nanofilter media, and 37.1 mmAq for the HEPA filter media. The particle size with minimum efficiency decreases with the decreasing fiber diameter. And the minimum efficiency becomes greater as the fiber diameter is decreased.
Keywords: Electrospinning; Nanofibers; Nanofilter; MPPS; Nano-particle

We present a simple strategy to reduce the writing time of electron beam lithography (EBL) by using a highly sensitive Shipley’s UV-5 resist while reducing proximity effects by depositing a thin film of silicon dioxide (SiO2) on silicon substrate. It was found that a simple insertion of a thin SiO2 film greatly reduced proximity effects, thereby providing enhanced resolution and better pattern fidelity. To support this conclusion, the bottom line width and sidewall slope of the developed pattern were analyzed for each substrate with different film thickness.
Keywords: Electron Beam Lithography (EBL); Proximity Effect; Thin Film; Silicon Dioxide

Nanoparticles are widely used in various applications such as catalysts, mechanical polishing, composite materials, size standards, and structural templates. For those applications, sometimes it is necessary to sample nanoparticles onto clean substrates and onto a designated area. In this article, electrophoresis is demonstrated as a very feasible method to sample the desired number of particles onto a specific area of a substrate without contamination problems. In addition, an analytical equation was derived for estimation of deposition area, and compared with the experimental results. Pure copper particles generated by spray pyrolysis were used for size-classifications and depositions. Particle depositions were performed at 2,000 V and 7,000 V, and light scattering parameters from those deposited samples were measured; results showed good agreement of deposition area between estimations and measurements. Therefore, the use of the electrophoresis is promising in sampling particulates onto clean substrates without contamination and onto the designated sampling area with controlled number density.
Keywords: Nanoparticles; Electric Field; Aerosol; Deposition

Gold nanoparticles (AuNPs) are used as fundamental materials in chemical/biological sensor applications, such as the DNA-AuNPs complex system for colorimetric sensor. As a result, the immobilization of AuNPs on target substrates is an important issue. In this study, we investigated the deposition of AuNPs on an amine-derivatized silicon wafer by in-situ AFM. Liquid-AFM allows structural changes and reaction kinetics of biomaterials and organic/inorganic nanomaterials in liquid media to be analyzed in-situ. The results showed that AuNPs were immobilized on an aminefunctionalized silicon wafer within a period of 1.5 hr.
Keywords: AFM; Gold Nanoparticles; Self-assembly; Liquid-AFM

Anodic oxidation via atomic force microscopy is a promising method for creating submicron-sized silicon dioxide patterns on a local surface. The area patterned by AFM anodic oxidation (AAO) has different chemical properties from the non-patterned area, and thus site-selective modification of patterned surfaces is quite possible. In this study, we combined the AAO with self-assembly method and/or wet chemical etching method for the fabrication of positive and/or negative structures. These locally modified surfaces could be used to the site-selective arrangement and integration of various materials based on a pre-described pattern.
Keywords: AFM; Anodic Oxidation; Etching; Pattern; Self-assembly

pH-dependent release property of dioleoylphosphatidyl ethanolamine liposomes by Seong Min Cho; Hyeon Yong Lee; Jin-Chul Kim (390-393).
pH-sensitive liposomes were prepared by a detergent removal method. Dioleoylphosphatidylethanolamine (DOPE) and cholesteryl hemisuccinate (CHEMS) were combined for the preparation of the liposomes so that the molar ratios of DOPE to CHEMS are 9/1, 8/2, 6/4 and 5/5. On transmission electron micrographs, hundreds of nm sized-multilamella vesicles were observed. The degrees of fluorescence quenching were approximately 70–80%, indicating that closed vesicles were formed. According to the results of the pH-dependent release experiment with the liposome composed of DOPE/CHEMS (5/5), no significant release was observed in the pH region ranging from 6 to 8. At pH of 5, an appreciable amount of calcein was released. The patterns of pH-dependent releases from liposomes composed of DOPE/CHEMS (6/4) and DOPE/CHEMS (8/2) were almost the same as those from liposomes composed of DOPE/ CHEMS (5/5). With the liposomes composed of DOPE/CHEMS (9/1), unlike the other liposomes described above, almost 90% release was observed at pH 6. In this case, since the amount of a complementary molecule, CHEMS, is relatively small, the liposomes would be subjective to destabilization even at a small change in the degree of deionization of the carboxylic group. This may explain why the liposome of DOPE/CHEMS (9/1) exhibits a significant release at a relatively high pH, pH 6.0.
Keywords: Liposome; Dioleoylphosphatidylethanolamine; Cholesteryl Hemisuccinate; pH-sensitive Release