• Biotechnology and Bioprocess Engineering:BBE
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• v.6 no.6
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• pp.363-375
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• 2001

Chromatography has been method of choice for the separation complex biologi-cal mixtures fro analytical purpose, particularly for the last fifty years. Its use has recently been extended to preparative separation where the productivity relative to the amount of resin and sol-vent used is a matter of concern. To overcome the inherent thermodynamic inefficiency of batch chromatography, as exemplified by the partial temporal usage of the resin and dilution of the product with the solvent, chromatography has been continually modified by separation engineers. Column switching and recycling represnet some of the process modifications that have brought high productivity to chromatography. Recently, the simulated moving bed (SMB) method, which claims a high separation efficiency based on counter-current moving bed chromatography. has be-come the mainstay of preparative separation, especially in chiral separation. Accordingly, this pa-per reviews the current status of SMB along with several chromatographic modification, which may be helpful in routine laboratory and industrial chromatographic practices.

• Journal of the Korean GEO-environmental Society
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• v.10 no.7
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• pp.125-133
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• 2009

Wastewater sludge had normally filled up in land before revising the law of waste material management in 2003, which does not permit landfill of organic sludge in Korea. After the law, most sludge has been littered in the ocean up to now. However, due to the London Convention 96 Protocol, littering sludge in the ocean will also be prohibited after 2011. This Protocol makes countries find out new methods to treat wastewater sludge. There is no exception in Korea too. Many researchers have urgently try to find out better ways to treat sludge. One of ways is to make sludge recycle energy and the success of it depends on drying method. Specifically, it really depends how to make sludge dry ecologic friendly and economic efficiently. Therefore, wastewater sludge produced in Youngdong was analyzed to make it energy resources in this study. The sludge was tested to analyze the drying and chemical characteristics of it by irradiating microwave. In the result, it is sure that the sludge has little heavy metals as like as others in country side. High calories, 3370 Kcal, shows that it has good potential to be recycle energy. Moreover, weight deduction of the sludge vs. time shows long S-curve and has same deduction ratio. Specifically, S-curve can be divided by three sections based on the curvature points. There are steady state reduction ratio of weight and approximately 80% of weight duction in the second section. This results can be used to estimate the amount of sludge reduction in the full-scale microwave dryer. Drying capacity of microwave shows approximately 1.0 kg/kw/hr. It makes sure that sludge recycle energy has the potential of economic efficiency too.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2003.10a
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• pp.116-121
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• 2003

In this study, the thermal degradation process has been investigated at various reaction temperature$(350{\sim}400^{\circ}C)$ and times$(30{\sim}120\;min)$ in order to recycle waste plastic films as solid state wax. Waste plastic films were easily melted by adding a small amount of waxes. The effects of wax addition and nitrogen flow rate on their thermal degradation properties were investigated. FT-IR, GPC and viscometer were used to analyze properties of the solid wax including the structure, molicular weight distribution and melt viscosity. The average molecular weight of solid wax was decreased with increasing the reaction time, temperature and amount of wax added, Also, the viscosity of solid wax decreased with increasing the stirring speed at a constant reaction temperature and time, and its viscosity got close to zero above $390^{\circ}C$.

• Korean Chemical Engineering Research
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• v.56 no.1
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• pp.103-111
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• 2018

Transesterification of BHET (Bis (2-Hydroxyethyl) Terephthalate), monomer of PET (Poly Ethylene Terephthalate) to BHBT (Bis (4-Hydroxybutyl Terephthate), monomer of PBT (Poly Butylene Terephthalate), using 1,4-BD (1,4-butanediol) were investigated. Zinc acetate was used as a catalyst for the reaction. Amounts of BHET, EG, and THF (Tetrahydrofuran) in a batch reactor were measured for determining the reaction kinetics. Mathematical models of the batch reactor for the transesterification reaction were developed and used to characterize the reaction kinetics and the composition distribution of the reaction products. Model predictions for the transesterification were in good agreement with experimental results.

• Journal of Adhesion and Interface
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• v.22 no.2
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• pp.69-77
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• 2021

A variety of efforts are attempted to make the world sustainable in fabrication industries worldwide. To achieve the goals, a new design concept for products is one of crucial factors to be able to dismantle them after use in easy and simple ways. New debonding technologies have been developed in recent years for the recycle and/or repair of bonded structures, where the bonds are broken without the damage of the components and make recycling easier. Some representative technologies of controlled delamination materials (CDM) are reviewed with an emphasis on light induced debonding of adhesives. We also describe current applications of light induced CDMs as temporary bondable films in semiconductor and display industries.

• Bulletin of the Korean Chemical Society
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• v.33 no.4
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• pp.1279-1284
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• 2012

Silica supported $Cs_{2.5}H_{0.5}PMo_{12}O_{40}$ catalyst was prepared through sol-gel method with ethyl silicate-40 as silicon resource and characterized by X-ray diffraction, infrared spectroscopy, scanning electron microscopy, nitrogen adsorption-desorption and potentiometric titration methods. The $Cs_{2.5}H_{0.5}PMo_{12}O_{40}$ particles with Keggin-type structure well dispersed on the surface of silica, and the catalyst exhibited high surface area and acidity. The catalytic performance of the catalysts for benzene liquid-phase nitration was examined with 65% nitric acid as nitrating agent, and the effects of various parameters were tested, which including temperature, time and amount of catalyst, reactants ratio, especially the recycle of catalyst was emphasized. Benzene was effectively nitrated to mononitro-benzene with high conversion (95%) in optimized conditions. Most importantly, the supported catalyst was proved has excellent stability in the nitration progress, and there were no any other organic solvent and sulfuric acid were used in the reaction system, so the liquid-phase nitration of benzene that we developed was an eco-friendly and attractive alternative for the commercial technology.

• Korean Chemical Engineering Research
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• v.50 no.5
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• pp.866-873
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• 2012

IgY (Immunoglobulin Yolk) is a specific antibody in egg yolk, and it protects human body from virus and antigen. There are a lot of egg yolk components such as lipoprotein and protein. To separate IgY, HPLC (High Performance Liquid Chromatography) and precipitation were used in a batch mode and SMB (Simulated Moving Bed) was adopted for continuous purification of yolk proteins. IgY and other proteins in yolk were separated by using three-zone and four-zone SMB chromatography. Before performing SMB experiments, batch chromatography simulation parameters and adsorption isotherms were obtained. The parameters of batch chromatography were used to simulate SMB using Aspen chromatography. To compare three-zone and four-zone SMB chromatography, simulations in $m_2-m_3$ plane on the triangle theory were carried out. In terms of concentration and purity of both IgY and other lipoproteins, 3-zone SMB process is considered as ideal at the vertex of triangle ($m_2$, $m_3$=0.1, 1.1). 4-zone SMB yields the highest IgY purity at the coordinate ($m_2$, $m_3$=0.06, 0.5), which is the pure raffinate region. In 3-zone SMB without recycle, other lipoproteins in extract are largely affected in purity by small shift from the vertex of triangle ($m_2$, $m_3$=0.1, 1.1).

• Korean Chemical Engineering Research
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• v.52 no.1
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• pp.45-51
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• 2014

This is to study the effects of various pretreatment methods of agricultural residue, corn stover, and to compare the feature and pros and cons of each method including dilute sulfuric acid (DSA), soaking in aqueous ammonia (SAA), and ammonia recycle percolation (ARP). In order to convert corn stover to ethanol, various pretreatments followed by simultaneous saccharification and co-fermentation (SSCF) were tested and evaluated in terms of ethanol yield. With 3%, w/w of glucan loading using ARP-, DSA-, and SAA-treated solids, SSCFs using recombinant E. coli strain (ATCC$^{(R)}$ 55124) with commercial enzymes (15 FPU of Spezyme CP/g-glucan and 30 CBU/g-glucan enzyme loading) were tested. In the SSCF tests, 87, 90, and 78% of theoretical maximum ethanol yield were observed using ARP-, DSA-, and SAA-treated solids, respectively, which were 69, 58, and 74% on the basis of total carbohydrates (glucan + xylan) in the untreated corn stover. Ethanol yield of SAA-treated solid was higher than those of ARP- and DSA-treated solids. In addition, SSCF test using treated solids plus pretreated hydrolysate indicated that the DSA-treated hydrolysate showed the strongest inhibition effect on the KO11 strain, whereas the ARP-treated hydrolysate was found to have the second strongest inhibition effect. Bioconversion scheme using SAA pretreatment and SSCF can make the downstream process simple, which is suggested to produce ethanol economically because utilization of hemicellulose in the hydrolysate is not necessary.

• Korean Journal of Materials Research
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• v.22 no.4
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• pp.174-179
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• 2012

In this study, we demonstrated a simple and eco-friendly method, including mechanical polishing and attrition milling processes, to recycle sputtered indium tin oxide targets to indium tin oxide nanopowders and targets for sputtered transparent conductive films. The utilized indium tin oxide target was first pulverized to a powder of sub- to a few- micrometer size by polishing using a diamond particle coated polishing wheel. The calcination of the crushed indium tin oxide powder was carried out at $1000^{\circ}C$ for 1 h, based on the thermal behavior of the indium tin oxide powder; then, the powders were downsized to nanometer size by attrition milling. The average particle size of the indium tin oxide nanopowder was decreased by increasing attrition milling time and was approximately 30 nm after attrition milling for 15 h. The morphology, chemical composition, and microstructure of the recycled indium tin oxide nanopowder were investigated by FE-SEM, EDX, and TEM. A fully dense indium tin oxide sintered specimen with 97.4% of relative density was fabricated using the recycled indium tin oxide nanopowders under atmospheric pressure at $1500^{\circ}C$ for 4 h. The microstructure, phase, and purity of the indium tin oxide target were examined by FE-SEM, XRD, and ICP-MS.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.5
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• pp.450-457
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• 2004

In this research, the automatic synthesis of knowledge models is proposed. which are the basis of the methods using qualitative models adapted widely in fault diagnosis and hazard evaluation of chemical processes. To provide an easy and fast way to construct accurate causal model of the target process, the Role-Behavior modeling method is developed to represent the knowledge of modularized process units. In this modeling method, Fault-Behavior model and Structure-Role model present the relationship of the internal behaviors and faults in the process units and the relationship between process units respectively. Through the multiple modeling techniques, the knowledge is separated into what is independent of process and dependent on process to provide the extensibility and portability in model building, and possibility in the automatic synthesis. By taking advantage of the Role-Behavior Model, an algorithm is proposed to synthesize the plant-wide causal model, Fault-Causality Graph (FCG) from specific Fault-Behavior models of the each unit process, which are derived from generic Fault-Behavior models and Structure-Role model. To validate the proposed modeling method and algorithm, a system for building FCG model is developed on G2, an expert system development tool. Case study such as CSTR with recycle using the developed system showed that the proposed method and algorithm were remarkably effective in synthesizing the causal knowledge models for diagnosis of chemical processes.