• Clean Technology
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• v.26 no.2
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• pp.96-101
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• 2020

In this paper, the commercial feasibility of trigeneration, producing heat, power, and hydrogen (CHHP) and using biogas derived from macroalgae (i.e., seaweed biomass feedstock), are investigated. For this purpose, a commercial scale trigeneration process, consisting of three MW solid oxide fuel cells (SOFCs), gas turbine, and organic Rankine cycle, is designed conceptually and simulated using Aspen plus, a commercial process simulator. To produce hydrogen, a solid oxide fuel cell system is re-designed by the removal of after-burner and the addition of a water-gas shift reactor. The cost of each unit operation equipment in the process is estimated through the calculated heat and mass balances from simulation, with the techno-economic analysis following through. The designed CHHP process produces 2.3 MW of net power and 50 kg hr^-1 of hydrogen with an efficiency of 37% using 2 ton hr^-1 of biogas from 3.47 ton hr^-1 (dry basis) of brown algae as feedstock. Based on these results, a realistic scenario is evaluated economically and the breakeven electricity selling price (BESP) is calculated. The calculated BESP is ¢10.45 kWh^-1, which is comparable to or better than the conventional power generation. This means that the CHHP process based on SOFC can be a viable alternative when the technical targets on SOFC are reached.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.1
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• pp.26-33
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• 2017

The objective of this study was to evaluate the characteristic of adsorption by using a meso-porous adsorbent (MPA), and investigate the removal efficiency of geosmin which taste and odor causing compounds in drinking water supplies through batch test. The results for the adsorption isotherm was analyzed by using the Langmuir equation and Freundlich equation, generally being applied. And the study showed that the both Langmuir and Freundlich equation explains the results better. Both of pseudo-first-order model and pseudo-second-order model were respectively applied for evaluation of kinetic sorption property of geosmin onto MPA. The adsorption experiment results using MPA showed that maximum adsorption capacity of MPA was lower 7 times than that of GAC, and adsorption rate of MPA was faster 11 times than that of GAC, on the basis of pseudo-first-order model. Therefore, it was determined that MPA was effectively able to remove geosmin in drinking water supplies in short EBCT condition, but regeneration cycle in MAP process was shorter than that in conventional process.

• Journal of Korean Society of Forest Science
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• v.79 no.3
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• pp.285-289
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• 1990

Soil N mineralization and nitrification can be measured conveniently using mixed bed (cation and anion) exchange resin bags. However, appropriate use of these resin bags requires pretreatment to avoid colorimetric interference and standardize N ion adsorption. Three pretreatments were evaluated : control (untreated), 2 M NaCl with a distilled water rinse, and 4 M NaCl. The 4 M NaCl treatment was effective at removing background levels of $NH_4{^+}$ and $NO_3{^-}$, but adsorbed low amounts (about 40%) of inorganic N from standard solutions. Untreated resin bags adsorbed a constant, higher amount of $NO_3{^-}$ (60%), but did not remove background levels of $NH_4{^+}$. The 2 M NaCl treatment followed by a distilled water rinse performed best : it removed background $NH_4{^+}$ and adsorbed a constant amount of both $NH_4{^+}$ (70%) and $NO_3{^-}$ (60%). Because the ion exchange resin is fairly expensive, we also tested if the resin bags could be reused. Resin bags were either loaded with $NH_4{^+}$ and $NO_3{^-}$ in the laboratory or incubated in soil in the field, desorbed with the 2 M NaCl treatment, and then loaded with standard $NH_4{^+}$ and $NO_3{^-}$ solutions. Lab loaded resin bags adsorbed about 60% of inorganic N then loaded with 2.5 or $5.0mgN\;1^{-1}$ and 70% when loaded at 10 or $20mgN\;1^{-1}$, whereas reused field incubated bags showed the opposite adsorption efficiency. These results demonstrate that resin bags can give reproducible results, but care must be taken to evaluate the effect of pretreatment and potential for reuse.

• Resources Recycling
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• v.27 no.2
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• pp.38-47
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• 2018

Integrated gasification combined cycle (IGCC) is a next generation energy production technology that converts coal into syngas with enhanced power generation efficiency and environmental performance. IGCC produces almost coal gasification slag as the solid by-product. IGCC slag is generated about 140,000 tons for a year although recycling of it is still in the early stages. We evaluated the potential of IGCC slag which is generated from a pilot plant in South Korea as an alkali-activated cement. Samples which were activated with the combined activator of sodium silicate solution and caustic soda had an average compressive strength of 4.5 MPa, showing expansion. Expansion of the alkali-activated slag was presumed to be caused by free CaO in the slag, although it was not detected by the ethylene glycol method. Samples that were activated with the combined activator of sodium aluminate and caustic soda had an average compressive strength of 10 MPa. Hydroxy sodalite and $C_3AH_6$ were found to be the new crystalline phases. IGCC slag can be used as an alkali-activated material, but the strength performance should be improved with proper mix design approach to calculate optimum proportions which can alleviate the expansion issue at the same time.

• Korean Journal of Construction Engineering and Management
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• v.17 no.4
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• pp.3-11
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• 2016

Recently, overseas plant orders of domestic enterprises are steadily increased, and the amount of orders in the first half of 2014 were 93% increased compared to the previous year. In addition, now which is the third quarter of 2015, overseas plant orders are already over 249.8 billion dollars so the interests of plant industry research has been increased. In the life cycle of the plant project, CM before the construction stage is to complement the uncertainties that are inherent in the early stages of the project, and from the viewpoint of supporting the rational decision-making, the importance of its role is on the rise. Among them, excavating and investing participation plan in the planning stage is an important work that has a large impact force to influence the success and failure of future project. However, the work has become a problem with frequent consultations due to decision-making, continuous modification, and inefficient repetitive tasks. Therefore, it is needed that work process should be changed to effectively accommodate. The purpose of this paper is to derive the major work items for excavating and investing participation plan in the planning stage of the plant project, and establish a standardized work process through the Delphi analysis. The result of this study is expected to be utilized for EPC companies in ensuring the technical competitiveness in planning on overseas markets, and improve the efficiency of work.

• Korean Journal of Agricultural Science
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• v.28 no.2
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• pp.85-91
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• 2001

This study was carried out to investigate the effects of liquid boar semen on reproductive performance in swine artificial insemination. Many factors, which were breeds, time of insemination, breeding season, sperm per dose etc, have been tried to improve reproductive efficiency. Boars were raised at Swine Artificial Insemination Center in National Livestock Research Institute, Sunghwan, Chungnam, Korea. This experiment was carried out from 1995 to 2000. There were no differences in the fertility results compared with 3 breeds (Landrace, Yorkshire and Duroc), frequencies of artificial insemination (double and triple) per estrus cycle and different seasons by using liquid boar semen. There were no significant differences in conception rate, farrowing rate and litter size using 4 trials of 3.0, 2.5, 2.0 and $1.5{\times}10^9/80ml$ in liquid boar semen with 70% of motile sperm cells. We confirmed that the sperm number per dose of $1.5{\times}10^9/80ml$ could be used for commercial artificial insemination.

• Journal of Mushroom
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• v.3 no.1
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• pp.31-34
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• 2005

This experiment was carried out to examine on the physiological and cultural characteristics of commercial strain Kunneutari #3 of Pleurotus eryngii. The optimal medium suitable for mycelial growth was YM, and followed by MCM and PDA. Also this strain more faster mycelial growth as 6.1 cm/7days compared with commercial strain P. eryngii #1. The optimal mycelial growth temperature was $25{\sim}30^{\circ}C$. The fruitbody yield was increased 54% with $117{\pm}16g/850m{\ell}$ and the fruitbody shape and qualities of this strain was good. And individual weight was $41{\pm}27g$. Spawn run of P. eryngii #3 in bottle cultivation took 30 days and also it took 21 days from scratching of inoculum to harvest that was shorter 3 days than P. eryngii #1, respectively. Therefore, it is expected that cultivation for P. eryngii #3 strain will improve farmer's income by enhancing efficiency of facilities and shorten 6 days on cultivation period, in addition, getting more growing cycle of P. eryngii.

• Polymer(Korea)
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• v.38 no.6
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• pp.827-831
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• 2014

An organic radical polymer (ORP) was prepared by radical polymerization and following oxidation into nitroxyl radical. Two different oxidation methods were employed and their radical concentrations were measured using electroparamagnetic resonance spectroscopy (EPR) and UV-visible absorption (UV-vis) spectroscopy. From these measurements, $H_2O_2-Na_2WO_4$ oxidation method exhibited a complete oxidation, which resulted in 97.6% spin concentration. Also, it was revealed that convenient and cheap UV-vis measurement was useful for preliminary radical concentration comparison. After applied as a cathode material in lithium ion batteries, ORP electrode showed a high initial capacity ($110mAh\;g^{-1}$), a good initial efficiency (96%), a very high rate performance (70% charging during 1.2 min) and stable cycle performance.

• Journal of Service Research and Studies
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• v.10 no.3
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• pp.67-80
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• 2020

The information system audit service has been recognized for its effectiveness in improving the management efficiency of informatization projects in the public sector and improving the quality of information systems. However, according to several recent studies, it is not very helpful in securing quality by indicating formal audit performance and incorrect functions or errors in a short audit period. So, if the effectiveness of audit is proved to ensure the quality of the information system from the perspective of the software life cycle and to successfully operate and maintain it, the use of audit for the successful construction of the information system will be an essential factor. Therefore, this study investigated whether the current audit service users are satisfied with the current information system audit and what they expect. If it is different from what was expected, the difference between expectations and performance was analyzed to improve user satisfaction, and a survey was conducted through interviews with experts in the information system field. Based on the empirical results through the questionnaire, in order to reduce the difference in expectations from the user's point of view in the information system audit service, a plan to improve the audit system suitable for the new audit environment was proposed.

• Journal of Life Science
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• v.13 no.3
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• pp.241-247
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• 2003

While the DNA-protein kinase (DNA-PK) complex, comprised of DNA-PKcs and Ku80, is primary involved in the repair of DNA double-strand breaks, it is also believed to participate in additional cellular processes. Here, treatment of embryo fibroblasts (MEFs) derived from either wild-type (Wt) or DNA-PKcs-null (DNA-$PKcs^{-/-}$) mice with various stress inducing agents revealed that adriamycin was markedly more cytotoxic for $Ku80^{-/-}MEFs$ and led to their long-term accumulation in the $G_2$/M phase. This differential response was not due to differences in DNA repair, since adrimycin-triggered DNA damage was repaired with comparable efficiency in both Wt and $Ku80^{-/-}MEFs$, but was associated with differences in the expression of important cell cycle regulatory genes. Our results support the notion that Ku80-mediated cytoprotection and $G_2$/M-progression are not only dependent on the cell's DNA repair but also may reflect Ku80's influence on additional cellular processes such as gene expression.