• Resources Recycling
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• v.31 no.3
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• pp.81-87
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• 2022

Energy consumption per unit weight of metal (kwh/kg of metal) is one of the most important economic indicators in the process of molten salt electrolysis. It is related to the heat loss of salt bath and the current efficiency of the process. The current efficiency is highly dependent on electrolysis temperature. On the other hand, the temperature of salt bath may increase significantly due to the difference (larger energy input than consumption) in heat balance at the beginning of electrolysis, which may cause different electrolysis temperature from an initially targeted value. This results in a bad effect on current efficiency. Therefore, it will be helpful to the reduction of energy consumption to compare the calculated and measured values of the temperature change of salt bath through the heat balance review at the early stage of electrolysis and to evaluate the energy loss to outside. In this study, based on the authors' experimental data, the heat balance was reviewed at the beginning of the electrolysis, and it was possible to evaluate the energy loss to the outside and the increase of the temperature of the salt bath quantitatively. Through such a method, heat loss reduction plan can be derived and current efficiency can be improved so that energy consumption can be reduced.

• Journal of the Korean Institute of Gas
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• v.27 no.3
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• pp.19-26
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• 2023

Hydrogen, a clean energy source free of COx emissions, is poised to replace fossil fuels, with its usage on the rise. Despite its high energy content per unit mass, hydrogen faces limitations in storage and transportation due to its low storage density and challenges in long-term storage. In contrast, ammonia offers a high storage capacity per unit volume and is relatively easy to liquefy, making it an attractive option for storing and transporting large volumes of hydrogen. While NH₃ decomposition is an endothermic reaction, achieving excellent low-temperature catalytic activity is essential for process efficiency and cost-effectiveness. The study examined the effects of different zeolite types (5A, NaY, ZSM5) on NH₃ decomposition activity, considering differences in pore structure, cations, and Si/Al-ratio. Notably, the 5A zeolite facilitated the high dispersion of Ni across the surface, inside pores, and within the structure. Its low Si/Al ratio contributed to abundant acidity, enhancing ammonia adsorption. Additionally, the presence of Na and Ca cations in the support created medium basic sites that improved N₂ desorption rates. As a result, among the prepared catalysts, the 15 wt%Ni/5A catalyst exhibited the highest NH₃ conversion and a high H₂ formation rate of 23.5 mmol/g_cat·min (30,000 mL/g_cat·h, 600 ℃). This performance was attributed to the strong metal-support interaction and the enhancement of N₂ desorption rates through the presence of medium basic sites.

• Applied Chemistry for Engineering
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• v.34 no.3
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• pp.291-298
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• 2023

This research evaluates the sustainability of gasifying livestock manure to produce fuel gas from an economic and carbon emission perspective. The entire process, including gasification, fuel gas purification, and pipeline installation to transport the produced fuel gas to the demanding industrial complex, is analyzed for realistic feasibility. The study is conducted using an ASPEN PLUS simulation with experimental data. The results of the economic and CO₂ life cycle assessments confirm that the fuel gas produced from livestock manure is competitive with natural gas despite having a lower calorific value. When used as a fuel with a high hydrogen content, the fuel gas emits less CO₂ per calorific value, making it more environmentally friendly. A scenario analysis is also performed to determine the expected economics, with price competitiveness being influenced by several factors. Although a significant decrease in natural gas prices could reduce the price competitiveness of the proposed process, it can still be supported by government policies. The cash flow analysis also confirms the economic viability of the process.

• Journal of Climate Change Research
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• v.7 no.1
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• pp.59-68
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• 2016

The world's major countries have focused on the renewable energy industry as the solution to climate change and the energy crisis. Nevertheless, there are no studies on the economic effects of the renewable energy industry. This study analyzed the economic effects of Korea's renewable energy industry by using the 2010 Input-Output Table. It is estimated that Korea's renewable energy industry made a production-induced effect of 2.0262 won, and a value-added-induced effect of 0.6138 won through an increase in output growth of 1 won, and an employment-induced effect of 2.3046 labors through an increase in output growth of 1 billion won. Both the effect ratio and the response ratio were greater than 1, which means the renewable energy industry is an intermediate manufacturing industry whose forward linkage effect and backward linkage effects are large. These results show differences with previous studies that classified electricity sector and renewable energy industry into final primary production industries. It is expected that the economic effects of the renewable energy industry will become greater in the future. Therefore, research on statistics related to the renewable energy industry is needed for more precise analysis.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.1 s.53
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• pp.179-185
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• 2009

In recent, the investigations related to the FRP(Fiber Reinforced Polymers) have been increased due to their superior material and mechanical properties such as environmental resistance, high specific strength and stiffness. Considering these advantages, the FRP tube may be proper for strut on the PSC box girder bridge that can maximize the efficiency of cross section and are effective on economics and aesthetics of bridges. In this research, the specimen tests of the FRP tube and compression tests of the concrete member enclosed with the FRP were performed in order to evaluate the suitability of the FRP tubes, which are applied to the PSC box girder bridge with strut. The specific strength of concrete and the energy absorbing capacity as well as ductility were increased according to the experimental results, and it was found that FRP tubes have sufficient safety as strut member.

• Electronics and Telecommunications Trends
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• v.32 no.1
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• pp.61-71
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• 2017

최근 ICT 기술 및 생태 환경은 매우 빠르게 변화하고 있으며, 이러한 변화 속에서 가장 주목받고 있는 변화는 초연결 사회를 지향하면서 IoT를 활용한 서비스가 다양한 산업 분야에서 매우 빠르게 변화하고 있는 것이다. 그러나, IoT 환경에서 주고받는 데이터 및 정보가 신뢰받지 못한다면 IoT 서비스는 IoT 서비스 확산에 주요 걸림돌이 되어, ICT 융합 산업의 생태계 조성과 성장 및 신 산업 발굴에 커다란 장애물로 나타나게 될 가능성이 많을 것으로 예상된다. 이러한 위험성으로 인하여, ICT 서비스 산업의 신뢰 기반 인프라 조성은 IoT 기반의 다양한 공유 경제 서비스 실현 및 에너지, 교통, 의료 등 타 산업과의 ICT 융합 실현을 위한 필수 선행 조건으로 대두되고 있고, 이를 뒷받침하는 인프라 기술인 TII(Trusted Information Infrastructure) 기술 개발의 중요성이 증대되고 있다. 본고에서는 ICT 트러스트 정보 인프라(TII) 기술에 대한 국내외 기술 동향과 더불어, ETRI에서 개발하고 있는 TII 기술 및 이를 이용한 응용 서비스 사례, 그리고 표준화 동향 등에 대해 살펴본다.

• Electronics and Telecommunications Trends
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• v.28 no.3
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• pp.170-182
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• 2013

카자흐스탄은 한국의 기술과 문화에 대해 높게 평가하고 있으며 한국을 자국 경제발전의 롤모델로 인식하고 양국 간 관계를 전략적 동반자 관계로 격상시키는 한편 협력 분야를 에너지, 자원 분야에서 기초과학과 IT 분야로 확대하고 있다. ICT는 카자흐스탄이 산업 다각화를 위해 전략적으로 육성하고자 하는 분야로 막대한 ICT 프로젝트를 제시하며 세계적인 경쟁력을 가진 우리 ICT 기업의 투자와 참여를 적극 요청하고 있다. 카자흐스탄과는 과거 (주)대우의 카작텔레콤 인수를 시작으로 ETRI의 우정, 이러닝 등 기술 지원 사업과 정책자문 등 다양한 협력 사업 경험을 가지고 있다. 그러나 양국 정부의 지원을 바탕으로 협력 사업을 진행하는 공공기관이나 충분한 자체 사업 역량을 보유한 대기업에 비해 모든 면에서 열세인 중소기업은 정확한 정보를 바탕으로 구체적인 전략을 수립하고 현지에 진출해야만 성공할 가능성이 높다. 따라서 본고에서는 우리 ICT 기업의 카자흐스탄 시장 진출을 지원하기 위한 사전 연구로서 ICT 시장 현황을 파악하고 현지 시장 진출 시 고려해야 할 요인들을 소개하고, 전략적 접근 방법을 제시하고자 한다.

• Electronics and Telecommunications Trends
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• v.24 no.4
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• pp.135-146
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• 2009

박막 태양전지(Thin Film Solar Cells)는 기존의 결정질 실리콘 태양전지와는 달리 유리 등 저가의 기반을 활용하고 표면에 박막으로 실리콘 등 재료를 증축시킨 2세대 태양전지이다. 그동안 변환효율이 실리큰형보다 낮아 건물 외벽이나 기둥 등 일부 용도에만 사용이 국한되었다. 그러나 최근 들어 제조과정에 에너지가 적게 소모되어 짧은 기간 내에 투자비용을 회수할 수 있고, 소재비용도 대폭 줄일 수 있는 등 뛰어난 경제성으로 인해 태양전지 업체들이 투자를 늘리고 신규업체가 진입하는 등 박막 태양전지가 유망 태양전지 아이템으로 부상하고 있다.

• Environmental and Resource Economics Review
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• v.21 no.1
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• pp.93-127
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• 2012

We estimate how much KEPCO can save their loss and how much social welfare can be increased by applying the real-time pricing instead of current regulated retail price in the electricity market in order to analyze the problem of the regulated retail price which is fixed below the marginal cost. We estimate the demand functions of peak time and off-peak time in summer (June to August) and winter (December to February). We construct the supply function based on hourly step-wise linear marginal cost functions, too. We find that the increase of social welfare will be 67 billion won in summer if the fixed retail price is changed into the real-time pricing scheme. The total 705 billion won will be transferred from consumer surplus to producer surplus and the rest (67 billion won) will be saved from the reduction of deadweight loss among KEPCO's loss. In winter, the increase of social surplus will be 225 billion won and 1,174 billion won of KEPCO's loss will be transferred from consumer surplus. As a result, we conclude that the regulation of the retail price in the electricity market induces the social welfare loss and KEPCO suffers a huge loss.

• Clean Technology
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• v.26 no.4
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• pp.239-250
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• 2020

Biomass is an abundant renewable energy resource that can replace fossil fuels for the reduction of greenhouse gas (GHG). Indonesia has a large number of cheap biomass feedstocks, such as reforestation (waste wood) and palm residues (empty fruit bunch or EFB). In general, raw biomass contains more than 20% moisture and lacks calorific value, energy density, grindability, and combustion efficiency. Those properties are not acceptable fuel attributes as the conditions currently stand. Recently, torrefaction facilities, especially in European countries, have been built to upgrade raw biomass to solid fuel with high quality. In Korea, there is no significant market for torrefied solid fuel (co-firing) made of biomass residues, and only the wood pellet market presently thrives (~ 2 million ton yr-1). However, increasing demand for an upgraded solid fuel exists. In Indonesia, torrefied woody residues as co-firing fuel are economically feasible under the governmental promotion of renewable energy such as in feed-in-tariff (FIT). EFB, one of the chief palm residues, could replace coal in cement kiln when the emission trading system (ETS) and clean development mechanism (CDM) system are implemented. However, technical issues such as slagging (alkali metal) and corrosion (chlorine) should be addressed to utilize torrefied EFB at a pulverized coal boiler.