• KSBB Journal
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• v.15 no.2
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• pp.201-207
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• 2000

The traditional ripening method of clay was analyzed. An advanced refining method of clay using enrichment cultures of iron r reducing bacteria was developed. After the traditional ripening, the whiteness of the clay was increased due to removal of | iron impurities by inhabitant dissilmaltien with iron reducing bacteria. Other characteristics of the refined clay such as v viscosity, plasticity, and strength were also improved by iron reducing bacteria. An advanced method of clay refinement with a anaerobic enrichment cultivation of iron reducing bacteria supplemented with an extra carbon source such as glucose was s suggested. When the clay was treated by the advanced method. the refinement time could be reduced to 1/6 of that r required by the traditional method. The physical properties of the refined clay by the advanced method were better than t those of the traditionally refined clay.

• Journal of the Society of Naval Architects of Korea
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• v.57 no.4
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• pp.241-253
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• 2020

The Small-Unit Riverine Craft (SURC) is a small high-speed vessel used by navies and marine corps in relatively shallow waterway environments, such as riverine areas or littoral coasts. In the past, SURCs have primarily been rigid-hulled inflatable boats constructed using composite materials such as glass fiber reinforced plastics. More recently, single-hull SURCs have been manufactured using aluminum for weight reduction. In this study, a Carbon Fiber Reinforced Polymer (CFRP) material was applied instead to examine its feasibility in the basic design of an SURC with a hull length of 10 m. The CFRP structural design was obtained using the properties of a marine CFRP laminate, determined in a previous study. Next, the designed CFRP SURC was modeled to confirm its functionality, then compared with existing aluminum SURCs, indicating that the CFRP SURC was 41.49 % lighter, reduced fuel consumption by 30 %, and could sail 50 NM further for every hour of engine operation. A method for reducing the high cost of carbon fiber was also proposed based on the adjustment of the carbon fiber content to provide the optimum strength where required. The data developed in this study can be used as a basis for further design of CFRP craft.

• Hwankyungkyoyuk
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• v.23 no.2
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• pp.65-81
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• 2010

Universities which have taken an important role to develop the human resources, became one of emitters of greenhouse gases, they need to find a way to reduce global warming gases through reduction of energy consumption. This study is intented to propose a solution that can reduce the greenhouse gases at universities located in Korea. To conduct this study, we have chosen a university at Wonju in Kangwon province for a case study and investigated the emissions of carbon dioxide from campus facilities and residential area. The data has become a footstone to estimate the assumed amount of carbon emission for top 23 energy consumption universities in Korea. We calculate the amount for carbon emission, not only for facilities in campus, but also for residential buildings, amount for emission is increased severely by showing $9780.94tCO_2$, which is 2.1 times more than average amount for emission of greenhouse gases researched in existing statistics. Universities have difficulty in introducing new energy generation system, as having been done business companies or other commercial facilities but they are required to introduce some educational methods since it is a academic space. Incentive to universities reducing carbon emission in campus is a system to provide incentives with students, professors, administrative personnels and others in campus as a compensation for their efforts to save energy. It is needed to establish the infrastructures for measuring energy consumption in campus.

• Journal of the Korea Institute of Building Construction
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• v.10 no.2
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• pp.59-66
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• 2010

The purpose of this study is to determine the possibilities of blending carbon black, which is known for its permeability as well as its strong heat and fire resistance, into concrete, in a manner that reinforces its strengths mentioned above. Experiments show that in non-solidified, fresh-mixed concrete, the addition of carbon black effectively reduced slump level and air content due to its absorptiveness and minute particle size. It also showed good results in terms of coagulation time, penetration resistance and bleeding level. In solid concrete, it showed better strength than plain concrete. Due to the pozzolanic reaction, its strength became more pronounced over time. At approximately 850 degrees Celsius, the heat and fire resistance level increased in parallel to the level of chemical substitution (by carbon black). Drying shrinkage level appeared to be optimal, and environmental assessment test results related to CO, CO2 and formaldehyde also scored better than plain concrete. In summary, with the appropriate use of AE water-reducing agents, carbon black can prove to be a strong candidate as an ingredient for industry-grade concrete.

• Resources Recycling
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• v.28 no.2
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• pp.40-45
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• 2019

During steelmaking in EAF, recycled scraps is used as a main material, melted by arc, and electricity use as a main energy. Slag foaming is an important technology for reducing electrical energy. CO gas generated by the reaction between injection carbon and (FeO), [C] and injection {$O_2$}. CO gas generated by this reaction is collected in slag, resulted in slag foaming. In general, the carbon materials used in the EAF process is anthracite and coke. This study investigated the effects of the carbon materials used on slag foaming in the steelmaking process. As a result of this study, the slag foaming height is increased by cokes rather than anthracite, and with an increase in the amount of particles samller than $500{\mu}m$. Based on these results, the application to the operation resulted in increase of slag forming height, reduction of injection carbon, and reduction of electrical energy.

• Journal of the Economic Geographical Society of Korea
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• v.24 no.4
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• pp.400-410
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• 2021

This study analyzed the determinants of carbon dioxide emissions through the expanded STIRPAT model using panel data from 16 metropolitan cities and provinces in Korea from 2000 to 2019. After testing cross-sectional dependence and coefficient heterogeneity of panel data, we performed analysis using MG, CCEMG, and AMG estimation methods reflected these characteristics. The results of analysis using the AMG estimation method are as follows. The coefficients of income, population, and energy intensity were statistically significant with a positive sign, but urbanization was statistically insignificant. Reduction of carbon dioxide emissions in Korea can be achieved through an increase in energy efficiency and sustainable economic growth. It is necessary to establish a policy that can contribute to sustainable economic growth by inducing productivity improvement through technology innovation reducing carbon dioxide emissions in the long-term as well as building a low-carbon society through active development of carbon dioxide reduction technology.

• Journal of the Korean Institute of Gas
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• v.27 no.3
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• pp.134-140
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• 2023

Activated carbon is a carbonaceous material mainly used as a gaseous or liquid adsorbent. As fire-related accidents occur consistently due to the accumulation of heat of adsorption and oxidation of volatile organic compounds, the explosive characteristics and thermal stability of powdered and granular activated carbon made from coal and coconut shells were evaluated. As a result of the particle size analysis, the powdered activated carbon was in the particle size range (0.4~3) ㎛, and thermal properties such as exothermic onset temperature and decomposition behavior were analyzed using a differential scanning calorimetry and a thermogravimetric analysis. As a result of the evaluation of the explosion hazards for dust, both coal-based and coconut-based powdered activated carbon are classified as St1 class with weak explosion, but this is a relative and does not mean that the explosion hazards is absolutely low. Therefore, it is necessary to establish countermeasures for reducing the damage.

• Composites Research
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• v.36 no.6
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• pp.422-428
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• 2023

The electrical contact resistance between the bipolar plate (BP) and the carbon felt electrode (CFE), which are in contact by the stack clamping pressure, has a great impact on the stack efficiency because of the relatively low clamping pressure of the vanadium redox flow battery (VRFB) stack. In this study, a polyethylene (PE) composite-CFE hybrid bipolar plate structure is developed through a local heat welding process to reduce such contact resistance and improve cell performance. The PE matrix of the carbon fiber composite BP is locally melted to create a direct contact structure between the carbon fibers of CFE and the carbon fibers of BP, thereby reducing the electrical contact resistance. Area specific resistance (ASR) and gas permeability are measured to evaluate the performance of the PE composite-CFE hybrid bipolar plate. In addition, an acid aging test is performed to measure stack reliability. Finally, a VFRB unit cell charge/discharge test is performed to compare and analyze the performance of the developed PE composite-CFE hybrid BP and the conventional BP.

• Korean Journal of Soil Science and Fertilizer
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• v.24 no.4
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• pp.278-285
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• 1991

This study was conducted to manufacture a good qualified organic fertilizer with cow dung through rapid composting process, and the proposal guideline of the degree of maturity could be estimated with the measurement of final product. It included total nitrogen content of above 2% on an oven-dry material basis, C/N ratio of below 20, CEC of more than about 60 me/100g, ratio of carbon in reducing sugar to the total carbon of below 35%, and temperature in pile of above $60^{\circ}C$. The total nitrogen content, the C/N ratio, and the Paper Chromatographic method couldn't be the guideline to evalute the maturity of cow dung compost. CEC was increased in increased fermentation and it was high in the high fermented temperature plots which were cow dung+ shredded bark in 1988, cow+dung+wood chips in 1989, and cow dung+rice straws in 1990. The ratio of carbon in reducing sugar to total carbon in 1990 was lower in cow dung+saw dust than cow dung+rice straws that was the highest temperature in pile. Generally cow dung was mixed well with saw dust and thus the total carbon of the product was high. The measurement of the temperature in pile seems to be a indirect guideline of maturity.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.6
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• pp.405-415
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• 2021

MMBR system has been suggested as a promising system to resolve harvesting problems induced from low settling efficiency of microalgae. And recently, a lot of research on reducing fouling at the MMBR system has investigated focused on EPS in many cases. EPS of microalgae mainly consists of polysaccharides and protein components, and is produced through photosynthesis and nitrogen-carbon metabolic pathways. Especially, P-EPS is one of major compounds which occur membrane fouling phenomenon, as its hydrophobic protein components cause floc formation and cake layer accumulation. And it is already known that almost every microalgae can metabolize P-EPS or Chl-a when nitrogen sources as a substrate is insufficient or exhausted situation. With the above backgrounds, uptake rates of P-EPS or Chl-a by Scenedesmus quadricauda according to the type of carbon source and nitrogen concentration were evaluated in order to verify correlation between carbon source vs P-EPS production, and indeed Scenedesmus quadricauda uses P-EPS or Chl-a when the amounts of nitrogen sourc es in the feed is not satisfied. As a result, it was shown that P-EPS and Chl-a production were increased proportional to nitrogen concentration under organic carbon condition. And especially, the amo unts of P-EPS and Chl-a in the cell were diminished with the nitrogen source becomes insufficient or exhausted. Because P-EPS accelerates fouling at the MMBR system, P-EPS degradation by Scenedesmus quadricauda in order to get nitrogen source may contribute to reducing fouling. About a affects of N-consumed Chl-a to the MMBR fouling, more survey is needed. On the contrary, considering the purpose of MMBR system of this study, i.e. harvesting useful high value microalgae efficiently feeding adequate industrial process wastewater, it seems like difficult to maintain satisfied metabolic activity and to harvest with high yield rate using nitrogen-poor MMBR feed.