• KEPCO Journal on Electric Power and Energy
• /
• v.4 no.1
• /
• pp.33-38
• /
• 2018

This study applied upgrades to the processes of a 10 MW wet amine $CO_2$ capture pilot plant and conducted performance evaluation. The 10 MW $CO_2$ Capture Pilot Plant is a facility that applies 1/50 of the combustion flue gas produced from a 500 MW coal-fired power plant, and is capable of capturing up to 200 tons of $CO_2$. This study aimed to quantitatively measure efficiency improvements of post-combustion $CO_2$ capture facilities resulting from process upgrades to propose reliable data for the first time in Korea. The key components of the process upgrades involve absorber intercooling, lean/rich amine exchanger efficiency improvements, reboiler steam TVR (Thermal Vapor Recompression), and lean amine MVR (Mechanical Vapor Recompression). The components were sequentially applied to test the energy reduction effect of each component. In addition, the performance evaluation was conducted with the absorber $CO_2$ removal efficiency maintained at the performance evaluation standard value proposed by the IEA-GHG ($CO_2$ removal rate: 90%). The absorbent used in the study was the highly efficient KoSol-5 that was developed by KEPCO (Korea Electric Power Corporation). From the performance evaluation results, it was found that the steam consumption (regeneration energy) for the regeneration of the absorbent decreased by $0.38GJ/tonCO_2$ after applying the process upgrades: from $2.93GJ/ton\;CO_2$ to $2.55GJ/tonCO_2$. This study confirmed the excellent performance of the post-combustion wet $CO_2$ capture process developed by KEPCO Research Institute (KEPRI) within KEPCO, and the process upgrades validated in this study are expected to substantially reduce $CO_2$ capture costs when applied in demonstration $CO_2$ capture plants.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.20 no.1
• /
• pp.29-35
• /
• 2010

This paper studies causes of the L-1 blade damage of a low pressure turbine, which was found during the scheduled maintenance, in 500 MW fossil power plants. Many failures of turbine blades are caused by the coupling of aerodynamic forcing with bladed-disk vibration characteristics. In this study the coupled vibration characteristics of the L-1 turbine bladed-disk in a fossil power plant is shown for the purpose of identifying the root cause of the damage and confirming equipment integrity. First, analytic and experimental modal analysis for the bladed-disk at zero rpm as well as a single blade were performed and analyzed in order to verify the finite element model, and then steady stresses, natural frequencies and corresponding mode shapes, dynamic stresses were calculated for the bladed-disk under operation. Centrifugal force and steady steam force were considered in calculation of steady and dynamic stress. The proximity of modes to sources of excitation was assessed by means of an interference diagram to examine resonances. In addition, fatigue analysis was done for the dangerous modes of operation by a local strain approach. It is expected that these dynamic characteristics will be used effectively to identify the root causes of blade failures and to perform prompt maintenance.

• Journal of The Korean Association of Information Education
• /
• v.19 no.1
• /
• pp.11-20
• /
• 2015

The researches on the concept of justice and utilization for Computational Thinking with SW education are being actively discussed. However, a program has developed in conjunction with the actual elementary curriculum is not much. In this study, we have developed an educational program in applied mathematics based on CT. First, a separated view for a CT Application of mathematical concepts and objectives are set in three different application models. In order to achieve the CT-based math lessons, we also have developed a teaching and learning materials. We applied the developed materials in class, and to evaluate the satisfaction of learners. In addition to the validation of school application, we conducted a survey of professionals and teachers. The results of the analysis, the data showed that are helpful in the development of the student' CT ability as well as the ability to be helpful teaching and learning in school.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.36 no.10
• /
• pp.989-999
• /
• 2012

An ejector is a fluid transportation device that operates based on the principle that a high-pressure fluid is spouted through a driving pipe and the pressure of a low-pressure fluid is increased through exchange of momentum with a low-pressure gas. Steam-steam ejectors have been widely used for suction, mixture, and dehydration. They can be easily used in places where fluid moves and expenses are reasonable. In addition, such ejectors are a semi-permanent fluid device that requires little maintenance. In this study, we present an optimized design by analyzing what cannot be obtained through experiments in order to improve the device performance, analyze general contents of a flow by acquiring exact test data on specific and interpretative areas using more advanced experimental techniques, and identify the flow characteristics of a branch pipe by examining the validity of experiments using computer hydrodynamics simulations.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.19 no.6
• /
• pp.1353-1358
• /
• 2015

The creative economy is the industrialization era, the information age, knowledge-based economy, linking the new economic paradigm. The core words of the creative economy are stand for creativity, innovation, consumer protection and utilization of intellectual property. Creative ideas are combined with software technology will make innovative ecosystem-based structured market such as Apple, Google, Facebook. Intangible assets attributable to creativity than ever before in human history that is important as the economic value. In addition, innovative ideas, creativity and economic growth beyond the knowledge and information society is required. Because the core has a fusion of science and technology, industry, culture and industry convergence, various genres of creative activity support, and cultural and high-tech fusion industries, such as content creation and job creation through economic traction is needed. In this study, we analyze the case of the US Smithsonian Institution proposes the direction of Science Museum in creative workforce.

• Journal of Advanced Marine Engineering and Technology
• /
• v.40 no.2
• /
• pp.102-106
• /
• 2016

An experimental study on the flow characteristics under various laminar coflow diffusion flames was conducted with a particular focus on the buoyancy force exerted from gaseous hydrocarbon fuels. Methane ($CH_4$), ethylene ($C_2H_4$), and n-butane ($C_4H_{10}$) were used as the fuels. A coflow burner and the Schlieren imaging technique were used to observe the flow field of each fuel near the nozzle exit as well as the flow characteristics in the flames. The results show that a vortex with a density heavier than air appeared in n-butane near the nozzle exit with a strong negative buoyancy on the fuel steam. As the Reynolds number increased through the control of the fuel velocity of the n-butane flame, the vortices were greater and the vortex tips were moved up from the nozzle exit. In addition, the heated nozzle affected the flow fields of the fuel steam near the nozzle exit.

• Korean Institute of Interior Design Journal
• /
• v.22 no.1
• /
• pp.222-230
• /
• 2013

The convergence progress in science technology and ensuing changes in educational environments require another huge change in education programs in the 21st century defined as a knowledge-based information society. But nowadays, prospective college students are increasingly avoiding natural science and engineering. So, educational fields in korea need suitable convergence educational programs (STEAM: science, technology, engineering, arts, mathematics) for creative competent person who is training and experiencing. In addition, environmental design fields are predicting about spread of Kinetic architecture. Therefore the aim of this study is developing convergence hand-on educational program which is incorporate robot science into environmental design for children. The program and teaching materials were developed by mapping between robot science and environmental design process leading the Design Promote Committee in KIID(Korea Institute of Interior Design) supported research teams in Hansung University. And then, For utility of the program, we had a 3 times of demonstration of empirical education. First, graduate students of design and robot major, and small group of children who are selected, at last, 63 children who are applying the program randomly. For more high quality program, we were conducting survey of post-empirical education evaluation for children and their parents. In conclusion, we found out highly satisfaction of the program those two groups. Also they need more organized places, time, task and so on. And the convergence educational program would develop by systematic approach and empirical research. At last, various and series convergence programs and teaching materials would develop creative competency based for regular and irregular courses of whole educational period.

• Biomolecules & Therapeutics
• /
• v.12 no.3
• /
• pp.189-193
• /
• 2004

Over the past several years, research efforts have been directed both at economically producing valuable substances from the wood biomass and at producing lignolytic enzymes at a lower cost. In the present study, we found that Phellinus igniarius, the basidiomycetes, secreted lignin peroxidase as a main lignolytic enzyme, which was detected maximum activity at 16th day of culture and showed 37 kDa of molecular mass in identification by activity assay and purification by anion-exchange chromatography. The Phellinus igniarius-derived lignin peroxidase hydrolyzed steam-exploded wood (Quercus mongolica) powder into small molecules showing cytotoxicity against cancer cel1s (HepG2 hepatoma, SK-N-SH neuroblastoma, B16 melanoma, MBT-2 bladder cancer). In addition, the enzyme hydrlysates of lignins (ELg) that were extracted from the steam-exploded oak showed more potent cytotoxic effects on the cancer cells than the enzyme hydrolysates of wood biomass (EWp), indicating that the cytotoxic effect of EWp may be due to the enzyme-degraded products of lignin among the lignocellulosics. Furthermore, the cytotoxic effect of ELg on Chang, normal liver cells, was much less potent than that of ELg on HepG2 and B16 cancer cells, indicating that the cytotoxic effect of ELg may be specific for cancer cells. The present results suggest that Phellinus igniarius may be a useful resource for the large-scale production of lignin peroxidase and that the lignin peroxidase may be applied for the generation of valuable biodegradation products from wood lignocellulosics for medical use.

• Korean Journal of Food Science and Technology
• /
• v.4 no.1
• /
• pp.1-5
• /
• 1972

This investigation was primarily carried out to establish the optimum conditions for the separation of sorbic acid, as an enzyme inhibitor, from dry mountain ash berries. The berries were crushed to $35{\sim}40\;mesh$, and leached with water to produce a reddish juice, which was concentrated to syrup after evaporation. Parasorbic acid was separated from the syrup by steam distillation in the presence of acid. In this study, the optimum experimental results for separation of parasorbic acid were obtained as follows : (1) the most applicable leaching time of the dry ash berries was about 6 hours at room temperature and less than 4 hours at $40^{\circ}C$ and (2) in steam distillation, after removal of malic acid, addition of 30 ml of sulfuric acid per 50 ml of syrup extracted from 100 g of the ash berries was very adequate. The purity of sorbic acid obtained experimentally through the isomerization technique was qualitatively examined by spectrophotometeric, paper chromatographic, and melting point measurements.

• YAKHAK HOEJI
• /
• v.41 no.1
• /
• pp.132-138
• /
• 1997

The antimicrobial activity of Manuka oil, a steam distillate from Leptospermum scoparium, was investigated, and it's MIC against ten kinds of microorganisms was determin ed. MICs against bacteria and fungi were measured by means of both two-fold dliution method and agar plate two-fold dilution method, respectively. MICs of Manuka oil against Staphylococcus aureus KCTC 1916 and Micrococcus luteus KCTC 1915, gram-positive microrganisms, were identical as 3.05 ${\mu}$g/ml, while it's antibacterial activity against gram-negative microrganisms such as Pseudomonas aeruginosa KCTC 2513, Escherichia coli KCFC 1682, Klebsiella pneunioniae KCTC 2001 or Proteus vulgaris KCTC 2433 was negligible(MIC: ${\geq}$ 1000 ${\mu}$g/ml), suggesting a high susceptibility of gram-positive bacteria to Manuka oil. In addition, MIC against Aspergillus niger KCTC 6077 was 24 ${\mu}$g/ml. and that against the other fungi, Tricophyton mentagrophytes KCTC 1374 and Candida albicans KCTC 1940 was ${\geq}$ 1000 ${\mu}$g/ml. When Manuka oil ointment was used in combination with other drugs. i.e.. gentamycin sulfate, chlotrimazol and hydrocortisone acetate, and diphenhydramine HCl and hydrocortisone acetate. it's antibacterial activity against Staphylococcus aureus KCTC 1916 was higher than Manuka oil ointment or other drugs alone. In conclusion, Manuka oil possesses a selective antibacterial activity against Staphylococcus aureus KCTC 1916, and can be used as a potent antibacterial agent against it.