• Korean Chemical Engineering Research
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• v.57 no.1
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• pp.51-57
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• 2019

A plant layout problem has a large impact on the overall construction cost of a plant. When determining a plant layout, various constraints associating with safety, environment, sufficient maintenance area, passages for workers, etc have to be considered together. In general plant layout problems, the main goal is to minimize the length of piping connecting equipments as satisfying various constraints. Since the process may suffer from the heat and friction loss, the piping length between equipments should be shorter. This problem can be represented by the mathematical formulation and the optimal solutions can be investigated by an optimization solver. General researches have overlooked many constraints such as maintenance spaces and safety distances between equipments. And, previous researches have tested benchmark processes. What the lack of general researches is that there is no realistic comparison. In this study, the plant layout of a real industrial C3MR (Propane precooling Mixed Refrigerant) process is studied. A MILP (Mixed Integer Linear Programming) including various constraints is developed. To avoid the violation of constraints, penalty functions are introduced. However, conventional optimization solvers handling the derivatives of an objective functions can not solve this problem due to the complexities of equations. Therefore, the PSO (Particle Swarm Optimization), which investigate an optimal solutions without differential equations, is selected to solve this problem. The results show that a proposed method contributes to saving the capital expenditures.

• Korean Journal of Food Science and Technology
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• v.10 no.4
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• pp.423-430
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• 1978

Since 1950 there has been a dramatic progress in rationalization of the production of sweet potato and potato starch in Japan. This enabled dextrose industry by enzymatic process to develop rapidly due to the success of enzymatic liquefaction and saccharification. Isomerization of glucose to fructose has been studied, and the immobilization of isomerases prompted its products on industrial scale in 1970. Another advance is the development of effective methods of producing high purity maltose. A malto-hexaose forming amylase was discovered in 1971 and attempts are being made for its pharmaceutical utilization. Saccharification of cellulose by cellulase has been studied. Conversion of starch to other polysaccharides is another example for the numerous Japanese activities.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.23-26
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• 2009

General characteristics of hydrogen and the ratio change of the two forms of hydrogen(ortho-hydrogen and para-hydrogen) as a function of the temperature were introduced. The unique characteristics of hydrogen, such as a wide range of flammability limits, low minimum ignition energy, low maximum inverse temperature, and hydrogen embrittlement were introduced. The process of producing the liquid hydrogen using pre-cooling and expansion engine and ortho-para conversion using the catalyst were introduced. Finally, the characteristics and the considerations as a propellant for liquid rocket were reviewed.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2006.09a
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• pp.3-12
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• 2006

The main feature of these total technologies is that we can constitute the optimum treatment scheme fitting to the property of wastes, amount of wastes and energy requirement. For high moisture content wastes or biomass resources, high pressure steam process (MMCS) for crush, dry and deodorize wastes to produce high quality fertilizer of fuel is most appropriate. For dry or semi-dry solid wastes, the STAR-MEET system can be applied to produce low-BTU gases for power generation using duel fueled diesel engines of Stirling engines, and the REPRES and HyPR-MEET systems can be applied to produce hydrogen rich medium-BTU gas. For waste plastics and oils, liquefaction technology is best fit to produce light oil or kerosene equivalent fuel oils. These total technologies are completely different from the existent waste treatment technologies based on land-filling or incineration, and are expected to disseminate all over the world in the near future.

• Journal of the Korean Society of Systems Engineering
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• v.4 no.1
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• pp.19-29
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• 2008

Traditionally gas plant R&D has had a world-wide weak position in terms of high technology. Especially System engineering did not exactly apply to gas plant construction. So, Gas Plant R&D Center is determined to make the establishment of the system engineering for the standard of gas plant. Gas Plant R&D Center has two projects. Firstly, the establishment of the R&D management system. Secondly, the system engineering which is included in the VE concept of EPC parts. But Gas Plant R&D Center exists in the particular conditions for successful development of the new process and core equipments. Now we will describe the establishment of R&D management system and particular conditions(Risk Conditions) for gas plant.

• Geomechanics and Engineering
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• v.17 no.5
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• pp.497-505
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• 2019

Biocementation based on the microbially induced calcite precipitation (MICP) process is a novel soil improvement method. Biocement can improve significantly the properties of soils by binding soil particles to increase the shear strength or filling in the pores to reduce the permeability of soil. In this paper, results of triaxial consolidated undrained (CU) tests and constant shear drained (CSD) tests on biocemented Ottawa sand are presented. In the CU tests, the biocemented sand had more dilative behaviour by showing a higher stress-strain curves and faster pore pressure reducing trends as compared with their untreated counterparts. In the CSD tests, the stress ratio q/p' at which biocemented sand became unstable was higher than that for untreated sands, implying that the biocementation will improve the stability of sand to water infiltration or liquefaction.

• Journal of Hydrogen and New Energy
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• v.34 no.5
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• pp.549-554
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• 2023

In this paper, three kinds of studies have been completed to obtain highly purified carbon dioxide having more than 7N purity as an electronic grade quality. PRO/II with PROVISION release January 2023 from AVEVA company was used, and Peng-Robinson equation of the state model with Twu's alpha function was selected for the modeling of the cryogenic distillation process. When using LN2 cold heat, we can obtain highest recovery of carbon dioxide as a bottom product for a cryogenic distillation column.

• Microbiology and Biotechnology Letters
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• v.20 no.4
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• pp.437-444
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• 1992

An innovative process for high fructose corn syrup (HFCS) production coupled with direct saccharification of raw corn starch in the agitated bead enzyme reactor (bioattitor) was investigated. The required high concentration/purity of glucose solution suitable for isomerization was produced directly in a bioattritor. without condensation of hydrolyzate, 398 g glucose/$\ell$ and 98% glucose content from 400 g/$\ell$ (w/v) of raw corn starch after 24 hours. The unsaccharified residual starch could be separated easily upon centrifugation, and resaccharified. The obtained solution also possessed other desirable requirements as substrate for isomerization, such as. low concentrations of denatured protein and calcium ions, thereby, simplified the purification step. The obtained glucose solution was isomerized in an enzyme reactor paked with immobilized glucose isomerase to evaluate the suitability as a substrate. The proposed new HFCS process seems to have many advantages over the conventional process via liquefaction-saccharification steps. The follow-up investigations of the proposed process need to be conducted to evaluate the feasibility of industrial application.

• Preventive Nutrition and Food Science
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• v.11 no.4
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• pp.318-322
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• 2006

The objective of this experiment was to investigate the effect of extrusion of ginseng roots in twin screw extruder on susceptibility of ginseng starch toward hydrolysis by ${\alpha}-amylase$ BAN 480L (Novozyme, Denmark) and cellulase Celluclast 150L and saccharification by amyloglucosidase AMG-E (Novozyme, Denmark). The extrusion was conducted at 22% and 30% moisture contents of feed at screw speed 300 rpm. Barrel temperature at zone 1 was adjusted at $100^{\circ}C$ and $120^{\circ}C$. The results showed that extrusion process improved the ginseng ${\alpha}-amylase$ susceptibility as compared to traditionally dried ginseng (white and red ginseng). Reducing sugar of hydrolyzed extruded samples was 2,500% of its initial concentration, whereas the reducing sugar of hydrolyzed non-extruded sample was only 200% of its initial concentration. However, addition of cellulase during liquefaction lowered the saccharification yield of both non-extruded and extruded samples as well.

• Journal of Hydrogen and New Energy
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• v.32 no.5
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• pp.356-364
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• 2021

During the hydrogen fueling process, hydrogen temperature inside the compressed tank were limited below 85℃ due to the allowable pressure of tank material. The chiller system to cool compressed hydrogen used R407C, greenhouse gas with a high global warming potential (GWP), as a refrigerant. To reduce greehouse gas emission, it should be replaced by refrigerant with a low GWP. This study proposes a chiller system for fueling hydrogen with R290, consisted in propane, by applying the C3 pre-cooled system use d in the LNG liquefaction process. The proposed system consisted of hydrogen compression and cooling sections and optimized the operating pressure through exergy analysis. It was also compared to the exergy efficiency with the existing system at the optimal operating pressure. The result showed that the optimal operating pressure is 700 kPa in 2-stage, 840 kPa/490 kPa in 3-stage, and the exergy efficiency increased by 17%.