• Food Science and Biotechnology
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• v.18 no.4
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• pp.855-860
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• 2009

Physicochemical properties of starches isolated from 3 new potato cultivars developed by Potato Valley Ltd. were investigated and compared to those of starch isolated from 'Superior' being distributed prominently in Korea. Significant differences were observed in physicochemical properties such as granule size, amylose content, phosphorus content, water binding capacity, swelling power, solubility, and in vitro digestibility of starches from different potato cultivars. Thermal properties were evaluated using differential scanning calorimetry (DSC), and onset gelatinization temperatire ($T_o$), peak temperature ($T_p$), and enthalpies of gelatinization (${\triangle}H$) of different potato cultivars ranged as $58.0{\pm}0.3-61.7{\pm}0.4^{\circ}C,\;63.7{\pm}0.2-$ $66.5{\pm}0.0^{\circ}C$, and $15.6{\pm}0.5-17.0{\pm}0.3$ J/g, respectively. Pasting properties were evaluated using a rapid visco analyzer (RVA), and pasting temperature, peak viscosity, and final viscosity of different potato cultivars ranged as $65.0{\pm}0.1-68.9{\pm}0.1^{\circ}C$, $8,163.7{\pm}196.3-9,035.7{\pm}6.4$ cp, and $4,397.7{\pm}166.7-7,025.0{\pm}271.3$ cp, respectively. Especially, 'Gogu valley' starch showed the highest values in the amylose and phosphorus content among tested potato cultivars and higher water binding capacity, swelling power, and solubility than those of other tested starches. And it also showed high pasting temperature, peak viscosity, trough viscosity, and final viscosity as compared to other tested starches.

• Korean Chemical Engineering Research
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• v.55 no.2
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• pp.180-189
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• 2017

Pharmaceutical co-crystals primarily to improve the solubility as well as stability of insoluble drug are to be investigated more intensively for IMDs as US FDA has reclassified co-crystal as a special case of solvates in August this year. In this study, we proposed a mechanism of indomethacin-saccharin co-crystal formation and the creation of transient indomethacin meta-stable form using in-line monitoring tools with the addition rate of anti-solvent as a critical process parameter. Among various instruments, we combined PVM (particle vision measurement) and FBRM (focused beam reflectance measurement) for the in-line monitoring of anti-solvent co-crystallization process. The off-line characterization of resulting powders was carried out employing the PXRD (powder x-ray diffraction) and DSC (differential scanning calorimeter). It was observed that the pathway to the final IMC-SAC co-crystal was significantly dependent upon the anti-solvent addition rate. The process conditions to obtain high quality co-crystal powder effectively were established. Consequently, we concluded that in-line monitoring combing the PVM and FBRM should be useful for the in-line monitoring of pharmaceutical co-crystallization processes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.12
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• pp.6973-6979
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• 2014

To mitigate global warming and climate change, many countries are investing massively on the development of CCS technology, which is assumed to be the key technology to reduce $CO_2$ emissions. CCS technology is comprised of the capture, transport, and storage processes. During the capture process, impurities other than $CO_2$ are inevitably flowed into the $CO_2$ stream. In the present study, corrosion characteristics of a phosphate coated tube for $CO_2$ transportation was investigated with a $CO_2$ stream composed of $CO_2$, $H_2O$, $SO_2$, and $NO_2$. The test specimen was a phosphate coated steel tube, which was filled with $CO_2$ stream with the impurities mentioned above. SEM-EDS analysis is conducted to investigate the corrosion behavior. The results showed that although the H2O concentration did not exceed the solubility limit, corrosion occurred in the specimen, which has an inflow of $SO_2$ or $NO_2$. This suggests that the $SO_2$, $NO_2$ and $H_2O$ concentration should be strictly controlled. These results suggest that the $SO_2$ and $NO_2$ concentration should be controlled below 175ppm and 65ppm, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.6 no.2
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• pp.144-148
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• 2005

At the previous papers, we showed that ${K_2}O$-CaO-${P_2}{O_5}$ glasses had a solubility in air so that they could be used for glass fertilizer. In this work, we fabricated the Eco-glass fertilizer containing trace elements of B, Mg, Zn, Fe, Cu, Co, Mo, the needed micronutrients for plants to grow, by a melt-quenching process. The dissolution properties in these glasses were investigated with a pH meter and an ICP analyzer. The trace elements doped glasses showed similar behavior in dissolutions and stability properties with the mother glass without containing trace elements. In addition, the dissolution amount of each trace elements depends on the mother glass composition and the quantity of each trace elements, which determine the dissolving velocity of chemical elements.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.947-954
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• 1997

Selected physical properties of cornmeal extrudates fortified with dairy products and extrusion process by $CO_2$ gas injection were analysed. Dairy products including whole milk powder, whey protein concentrate non-fat dry milk, and sodium caseinate were tested at the addition of 10% and 20%, based on cornmeal weight. $CO_2$ gas was injected to the barrel at the pressure of 0.7 and 1.4 MPa. Specific mechanical energy (SME) input was decreased by the addition of dairy products. Sodium caseinate had a little effect on decreasing the SME input, however whole milk powder tremendously reduced SME input when the concentration increased. An increase in milk product content resulted in increasing the piece density at the injection pressure of 0.7 MPa. At both 10% and 20% milk product content, the piece density was lowest at the injection pressure of 0.7 MPa. The sectional expansion index was highest at the injection pressure of 0.7 MPa. However, the specific length was constantly increased with the increase in $CO_2$ injection pressure. Water absorption index was decreased and water solubility index was increased by the addition of milk products. The injection pressure of $CO_2$ was optimum at 0.7 MPa. The addition of whole milk powder limited to puff the melt, but the other milk products tested resulted in puffing with $CO_2$ injection to 1.4 MPa.

• Korean Chemical Engineering Research
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• v.61 no.4
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• pp.555-560
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• 2023

Conventional aqueous amine-based CO₂ capture has a problem in that a large amount of renewable energy is required for CO₂ stripping and solvent regeneration in its industrial applications. This work proposes a water-lean absorbent that can reduce regeneration energy by lowering the water content in the absorbent with high absorption capacity for CO₂. To this purpose, this water-lean solvent introduced NMP (N-methyl-2-pyrrolidone), which has a higher physical solubility in CO₂ and a low specific heat capacity comparing to water, along with 3-methylaminopropylamine (MAPA), a diamine, into the absorbent. The circulating absorption capacity and absorption rate for CO₂ of this water-lean solvent were measured using a packed tower. When NMP was added to the absorbent, the absorption rate was improved. In the case of the absorbent containing 2.5M MAPA was used, the maximum circulating absorption capacity was obtained when 10 wt% of NMP was included in absorbent. The overall mass transfer coefficient increased as the concentration of NMP increased. However, at loading values higher than 0.5, the increment in mass transfer coefficient decreased as the concentration of NMP increased. When the lean loading value is low, the mass transfer resistance due to viscosity of the absorbent is low, so the overall mass transfer coefficient increases with the addition of NMP. However, as the lean loading value increases, the viscosity of the absorbent increases, and the diffusivity of CO₂ and MAPA decreases, resulting in sharply decreasing of the overall mass transfer coefficient.

• Journal of Periodontal and Implant Science
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• v.39 no.sup2
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• pp.231-237
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• 2009

Purpose: Cytolethal distending toxin (CDT) is a family of heat-labile cytotoxins produced by several gram-negative mucosa-associated pathogens, including Aggregatibacter actinomycetemcomitans. CDT is well known to be capable of inducing growth arrest, morphological alterations, and eventually death in various cells. CDT belongs to a tripartite $AB_2$ toxin (CdtB: the enzymatic A subunit; CdtA and CdtC: the heterodimeric B subunit). Previous studies proposed that CdtA and CdtC together bind to a cell surface receptor and glycolipids act as a receptor for A. actinomycetemcomitans CDT (AaCDT). In this study, recombinant CdtA and CdtC proteins of AaCDT were co-expressed in a bacterial expression system and tested for their affinity for $GM_1$ ganglioside. Methods: The genes for CdtA and CdtC from A. actinomycetemcomitans Y4 were utilized to construct the expression vectors, pRSET-cdtA and pET28a-cdtC. Both CdtA and CdtC proteins were expressed in Escherichia coli BL21(DE3) and then purified using hexahistidine (His6) tag. The identity of purified protein was confirmed by anti-His6 antibody and monoclonal anti-CdtA antibody. Furthermore, the affinity of recombinant protein to $GM_1$ ganglioside was checked through ELISA. Results: Recombinant CdtA and CdtC proteins were expressed as soluble proteins and reacted to anti-His6 and monoclonal anti-CdtA antibodies. ELISA revealed that purified soluble CdtA-CdtC protein bound to $GM_1$ ganglioside, while CdtA alone did not. Conclusions: Co-expression of CdtA and CdtC proteins enhanced the solubility of the proteins in E. coli, leading to convenient preparation of active CdtA-CdtC, a critical material for the study of AaCDT pathogenesis.

• Korean Chemical Engineering Research
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• v.45 no.1
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• pp.67-72
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• 2007

An efficient method for identification of MIMO state space model has been developed by combining partial least squares (PLS) regression, balanced realization, and balanced truncation. In the developed method, a MIMO system is decomposed into multiple MISO systems each of which is represented by a high-order ARX model and the parameters of the ARX models are estimated by PLS. Then, MISO state space models for respective MISO ARX transfer function are found through realization and combined to a MIMO state space model. Finally, a minimal balanced MIMO state space model is obtained through balanced realization and truncation. The proposed method was applied to the design of model predictive control for temperature control of a high pressure $CO_2$ solubility measurement system.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.44 no.1
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• pp.37-44
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• 2011

We investigated the optimum formulation to improve the gelling ability of squid, Dosidicus gigas, surimi. The solubility of minced squid muscle was highest at pH 10.7, and lowest at pH 5.0. The yields of conventional surimi and protein recovery after alkaline pH-shift processing were $68.1{\pm}2.4%$ and $65.3{\pm}2.6%$, respectively, whereas the protein recovery with acidic pH-shift processing was only $21.2{\pm}1.6%$. The addition of 5% starch decreased the breaking force regardless of the kind of starch, while the mixture of corn, potato, and wheat starch (total 15%) increased the breaking force by up to 1.9 fold. The addition of 5% egg white, 5% porcine plasma protein, 0.3% $CaCl_2$, and 0.3% Polymix GA significantly increased the breakingforce (P<0.05). None of the ingredients examined in this study significantly affected the deformation value (P<0.05). The optimum concentrations of egg white and $CaCl_2$ to obtain a breaking force of 55 g and a whiteness of 70 were 2.69% and 0.22%, respectively.

• Clean Technology
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• v.26 no.2
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• pp.116-121
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• 2020

In this paper, the recycling of waste Ni-MH battery by-products for electric vehicle is studied. Although rare earths elements still exist in waste Ni-MH battery by-products, they are not valuable as materials in the form of by-products (such as an insoluble substance). This study investigates the recovering of rare earth oxide for solvent extraction A/O ratio, substitution reaction, and reaction temperature, and scrubbing of the rare earth elements for high purity separation. The by-product (in the form of rare earth elements insoluble powder) is converted into hydroxide form using 30% sodium hydroxide solution. The remaining impurities are purified using the difference in solubility of oxalic acid. Subsequently, Yttrium is isolated by means of D2EHPA (Di-[2-ethylhexyl] phosphoric acid). After cerium is separated using potassium permanganate, lanthanum and neodymium are separated using PC88A (2-ethylhexylphosphonic acid mono-2-ethylhexyl ester) and it is calcinated at a temperature of 800 ℃. As a result of the physical and chemical measurement of the calcined lanthanum and neodymium powder, it is confirmed that the powder is a microsized porous powder in an oxide form of 99.9% or more. Rare earth oxides are recovered from Ni-MH battery by-products through two solvent extraction processes and one oxidation process. This study has regenerated lanthanum and neodymium oxide as a useful material.