• Nuclear Engineering and Technology
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• 제55권8호
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• pp.3071-3079
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• 2023

Helium production in the nuclear fuel matrix during irradiation plays a critical role in the design and performance of Gen-IV reactor fuel, as it represents a life-limiting factor for the operation of fuel pins. In this work, a surrogate model for the helium production rate in fast reactor MOX fuels is developed, targeting its inclusion in engineering tools such as fuel performance codes. This surrogate model is based on synthetic datasets obtained via the SCIANTIX burnup module. Such datasets are generated using Latin hypercube sampling to cover the range of input parameters (e.g., fuel initial composition, fission rate density, and irradiation time) and exploiting the low computation requirement of the burnup module itself. The surrogate model is verified against the SCIANTIX burnup module results for helium production with satisfactory performance.

• Advances in Energy Research
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• 제3권1호
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• pp.11-30
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• 2015

The covenant of Mayors initiative includes the commitment of the municipalities-signatories to reduce voluntarily the greenhouse gas emissions over 20--- by 2020 within their boundaries and obligates them to develop and submit an energy consumption analysis and a sustainable energy action plan within a year from the adhesion. The present paper discusses the energy profile of three medium-sized north-eastern Greek Municipalities (Kavala-MoK, Alexandroupolis-MoA, Drama-MoD) through the analysis of their municipal energy balance. The results of the total final energy consumption per capita include 14.10MWh/capita, 14.24MWh/capita and 12.91MWh/capita for MoK, MoA and MoD respectively. The analysis highlighted the increased energy consumption of the private sectors, namely residential and tertiary building sand private transport. The assessment of the municipalities' energy profiles along with examination of national regulations and action plans and investigation of best available practices within the Covenant of Mayors shaped the development of the sustainable energy action plans of the examined municipalities that is presented in this paper. The proposed pathway towards low-carbon municipalities can be considered a representative case study and a starting point for other municipalities with similar characteristics.

• 한국수소및신에너지학회논문집
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• 제19권2호
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• pp.145-155
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• 2008

This paper deals with an economic evaluation of hydrogen production by fermentation. We evaluate the economic feasibility of domestic hydrogen production by fermentation utilizing glucose and waste water sludge in terms of hydrogen production prices. In addition, we make some sensitivity analysis of hydrogen prices by changing the values of input factors such as the price of glucose, the capital cost of the hydrogen production system, and the hydrogen production yields. The estimated hydrogen prices of the two-step dark-light hydrogen production by fermentation utilizing glucose was $5,347won/kgH_2$, and the single-step hydrogen production by anaerobic fermentation utilizing waste water sludge was $4,255won/kgH_2$, respectively. It is expected that the hydrogen production price by anaerobic fermentation can be reduced if we produce methane or hydrogen utilizing by-products such as alcohols and organic acids, or the government imposes some legal regulations on the treatment of waste water sludge.

• BMB Reports
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• 제46권5호
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• pp.244-251
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• 2013

Lignocellulosic materials are commonly used in bio-$H_2$ production for the sustainable energy resource development as they are abundant, cheap, renewable and highly biodegradable. In the process of the bio-$H_2$ production, the pretreated lignocellulosic materials are firstly converted to monosaccharides by enzymolysis and then to $H_2$ by fermentation. Since the structures of lignocellulosic materials are rather complex, the hydrolysates vary with the used materials. Even using the same lignocellulosic materials, the hydrolysates also change with different pretreatment methods. It has been shown that the appropriate hydrolysate compositions can dramatically improve the biological activities and bio-$H_2$ production performances. Over the past decades, hydrolysis with respect to different lignocellulosic materials and pretreatments has been widely investigated. Besides, effects of the hydrolysates on the biohydrogen yields have also been examined. In this review, recent studies on hydrolysis as well as their effects on the biohydrogen production performance are summarized.

• 플랜트 저널
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• 제12권3호
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• pp.32-38
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• 2016

본 연구에서는 해안 복잡지형에 2열 배치된 풍력단지 운영사례를 분석하여 후류에 의한 풍력발전기의 영향을 분석하여 풍속의 변화 그리고 난류강도의 변화를 분석하였다. 주풍향 대비 인접 풍력발전기와 이격거리가 날개직경(rotor diameter,RD) 90m 기준 4RD인 경우 후류에 의해 풍속감소 및 난류강도의 증가로 인한 발전량의 감소를 확인 할 수 있었다. 특히 후류에의한 급격한 순간풍향의 변화시, 풍력발전기의 불시정지로 발전량이 현저히 감소되었고 이를 보완하기 위하여 요브레이크를 설비를 보강 함으로써 불시정지 빈도를 감소하고 발전량을 제고하는데 효과가 있음을 확인할 수 있었다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.478-481
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• 2006

Energy is vital to global prosperity, yet dependence on fossil fuels as our primary energy source contributes to global climate change environmental degradation, and health problems. Hydrogen $(H_2)$ offers tremendous potential as a clean renewable energy currency. Hydrogen has the highest gravimetric energy density of any known fuel and is compatible with electrochemical and combustion processes for energy conversion without producing carbon-based emission that contribute to environmental pollution and climate change. Numerous methodologies have been developed for effective hydrogen production. Among them, the biological hydrogen production has gained attention, because hydrogen can be produced by cellular metabolismunder the presence of water and sunlight. The green alga Chlamydomonas reinhardtii is capable of sustained $H_2$ photoproduction when grown under sulfur deprived condition. Under sulfur deprived conditions, PSII and photosynthetic $O_2$ evolution are inactivated, resulting in shift from aerobic to anaerobic condition in the culture. After anaerobiosis, sulfur deprived algal cells induce a reversible hydrogenase and start to evolve $H_2$ gas in the light. According to above principle, we investigated the effect of induction parameters such as cell age, cell density. light intensity, and sulfate concentration under sulfur deprived condition We also developed continuous hydrogen production system by sulfate re-addition under sulfur deprived condition.

• 유기물자원화
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• 제19권1호
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• pp.57-63
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• 2011

화석연료가 고갈되어 감에 따라 사람들은 이를 대처할 수 있는 대체에너지를 찾기 시작했다. 이 대체 에너지는 환경 친화적이며 재생 가능해야 된다는 단서가 붙는데 그 중 가장 많은 주목을 받은 것이 수소이다. 현재 수소는 다양한 방법으로 생산되고 있는데 생물학적으로 수소를 생산하는 방법이 가장 환경 친화적인 방법으로 인식되고 있다. 그러나 아직 생물학적으로 수소를 생산하는 방법은 아직 상업화하기엔 경쟁력이 많이 부족하기 때문에 많은 연구자들이 바이오 수소 생산 방법과 그 생산성 및 생산수율을 높이기 위하여 노력하고 있다. 본 고에서는 생물학적 수소생산의 다양한 개발 접근방법들의 진행 추이를 정리하였다.

• 신재생에너지
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• 제19권2호
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• pp.13-22
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• 2023

With the increased interest in renewable energy, various hydrogen production technologies have been developed. Hydrogen production can be classified into green, blue, gray, and pink hydrogen depending on the production method; each method has different technical performance, costs, and CO₂ emission characteristics. Hence, selecting the technology priorities that meet the company strategy is essential to develop technologically and economically feasible projects and achieve the national carbon neutrality targets. In addition, in early development technologies, analyzing the technology investment priorities based on the company's strategy and establishing investment decisions such as budget and human resources allocation is important. This study proposes a method of selecting priorities for various hydrogen production technologies as a specific implementation plan to achieve the national carbon neutrality goal. In particular, we analyze key performance indicators for technology, economic feasibility, and environmental performance by various candidate technologies and suggest ways to score them. As a result of the analysis using the aforementioned method, the priority of steam methane reforming (SMR) technology combined with carbon capture & storage (CCS) was established to be high in terms of achieving the national carbon neutrality goal.

• 한국수소및신에너지학회논문집
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• 제21권1호
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• pp.12-18
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• 2010

Photobiological hydrogen production using Rhodobacter sphaeroides KD131 was studied on the effect of light intensities and nitrogen sources. Media containing malate and glutamate were shown higher hydrogen production rate than that containing succinate and $(NH_4)_2SO_4$ at the $110\;W/m^2$ illumination by halogen lamp at $30^{\circ}C$. Media lacking glutamate as the nitrogen source exhibited higher hydrogen production than that containing glutamate. Initial cell concentration was optimized to 1.0 at the absorbance of 660 nm. Hydrogen production was increased by increasing the light intensity from 0 to $216\;W/m^2$ but the increasing rate declined over $108\;W/m^2$.

• 한국수소및신에너지학회논문집
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• 제18권1호
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• pp.95-108
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• 2007

There are several methods for the hydrogen production such as steam reforming of natural gas, photocatalytic method, biological method, electrolysis and thermochemical method, etc. These days it has been widely studying for the hydrogen production method having low hydrogen production cost and high efficiency. In this paper, patents in the hydrogen production by water electrolysis were gathered and analyzed. The search range was limited in the open patents of USA(US), European Union(EP), Japan(JP), and Korea(KR) from 1996 to 2005. Patents were gathered by using key-words searching and filtered by filtering criteria. The trends of the patents was analyzed by the years, countries, companies, and technologies.