• Title/Summary/Keyword: 수행공학

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A Study on the Environmental Characteristics of Water Quality and Sediments in Suncheon Bay (순천만 수저질 환경특성에 관한 연구)

  • Park, Sangsook;Heo, Sung-sil;Choi, Jeong-min;Woo, Sung-won
    • Proceedings of the Plant Resources Society of Korea Conference
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    • 2019.10a
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    • pp.9-10
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    • 2019
  • 순천만은 순천시의 남쪽에 위치하여 여수반도와 고흥반도의 사이에 있는 만 지형 형태로 만 전체를 순천만이라고도 하나, 보통 고흥군반도와 여수반도 사이의 만을 여자만이라 하고 만내부에 위치한 여자도라는 섬의 위쪽으로 순천시의 해안하구에 형성된 지역을 순천만이라 일컫는다. 순천만은 순천시에서 유입되는 동천과 이사천 및 해룡천의 하류에 형성되어 있어서 육지부에서 유입되는 퇴적물과 유기물로 인하여 갯벌과 갈대등이 잘 형성된 습지로서 2003년 12월 31일 해양수산부 갯벌 습지보존지역으로 지정되어 관리되고 있으며, 2004년에는 동북아 두루미 보호 국제네트워크에 가입하였고, 2006년 1월 국내 연안습지로는 최초로 람사르협약에 "Suncheon Bay"로 등록되었으며, 2016년 6월에는 람사르습지로 지정된 국내외적으로 중요한 습지이다. 순천만습지에 형성되어 있는 갯벌($28.0km^2$)은 세계 5대 연안습지 중 하나로서, 넓은 사니질 갯벌과 갈대군락이 잘 발달되어 있는 생태계의 보고(寶庫)이자 소중한 생태자원으로서, 순천시에서는 순천만을 자연생태공원으로 지정하여 보호 관리하고 있으며, 각종 자연학습자료들과 영상물들을 갖춘 생태전시관과 갈대숲 탐방로, 용산전망대, 야생화 정원, 담수습지, 갈대정자, 갯벌관찰대 등 사계절 생태체험을 위한 각종 시설들을 잘 갖춰놓고 많은 관광객의 이용할 수 있도록 하고 있다. 갯벌은 바닷가의 넓은 벌판이란 뜻으로서 삼면이 바다인 우리나라는 갯벌의 전체 면적이 약 $2,500km^2$에 달하는데 여기에는 많은 종류의 다양한 생물들이 살아가고 있으며 어민들의 생계에 지대한 영향을 주고있다. 이러한 갯벌은 퇴적된 입자의 구성에 따라 펄갯벌, 모래갯벌, 혼합갯벌 등으로 구별되는데 이에 따라 갯벌 생태계를 구성하고 있는 생물들의 종류도 바뀌게 된다. 순천만갯벌과 여기에 조성되어 있는 습지환경에 따라 확인되고 있는 수산자원으로는 새꼬막, 꼬막, 눈알고둥, 갯고둥, 비툴이고둥, 돌조개, 접시조개, 새알조개, 가무락조개, 바지락, 우럭, 가재붙이, 방게, 칠게, 농게 등의 저서 생물들과 짱뚱어, 문절망둑 등의 어류가 있으며, 해조류로 우뭇가사리 등이 있고, 인근의 어민들의 어업형태는 꼬막 등 패류의 채취나 종패를 뿌려 일정기간 양성하여 수확하는 양식업, 육상부에서 폐염전 등을 활용한 전어나 새우 등을 양식하는 양식업, 수산물을 직접 손이나 간단한 도구를 이용하여 잡는 맨손 어업 형태가 주를 이루고 있는 것으로 나타나고 있다. 이와 같이 국내외적으로 중요할 뿐만 아니라 인근의 어민들의 생계에도 지대한 영향을 미치고 있는 순천만의 습지는 뻘층이 깊고, 분해성 미생물이 다양하게 서식하여 유기물 분해능력이 뛰어나며, 유기영양분이 풍부하여 우리나라에서 가장 질이 좋은 습지로 평가되고 있으나, 순천시 등 순천만 인근에 거주하고 있는 인간의 활동에 따른 간섭에 많은 영향을 받고 있으며, 이에 따라 끊임없는 생태환경이 변화하고 있어서 순천만의 효율적인 보전 및 지속가능한 이용을 위해서는 생태계에서 가장 기본적인 요소인 수 저질 환경의 지속적이고 체계적인 조사 및 관리가 필요하다. 한편, 오염물질의 70% 이상은 하천이나 강을 통해서 해역으로 유입된다고 알려져 있기 때문에 생태계의 보고(寶庫)라고 알려진 순천만의 지속적인 보존 및 관리를 위해서는 유입수계 하천의 수질현황 및 오염물질의 주요 배출원을 파악하고, 이에 대한 저감대책을 수립할 필요가 있다. 따라서 본 연구는 순천만의 수저질 특성과 여기에 유입되는 하천의 수질환경 현황 및 오염원을 파악함으로써 순천만의 보전을 위한 효율적 관리방안을 제시하는 것을 목적으로 수행되었다. 연구의 결과에 따르면, 순천만의 수질평가지수에 의한 등급(WQI)은 III등급으로 나타나고 있으며, 득량만, 광양만 등에 비해 비교적 높은 유기물 및 T-N, T-P의 농도 분포를 보이고 있는 것으로 조사되었다. 이는 순천만에 유입되는 하수종말처리장의 방류수와 도시하수가 유입되어 그대로 방류되고 있는 해룡천 및 연안에 위치한 어촌으로부터 직접 방류되고 있는 일부 정화조 유출수 등, 다양한 원인에 의한 것으로 판단되며 이들의 관리가 부실할 경우 순천만의 갯벌과 습지의 지속가능한 생태환경유지는 쉽지 않다. 따라서 이를 효율적으로 관리하기 위해서는 순천만 연안의 오염물질 방류를 총량관리로 전환하여 철저히 관리하는 것이 필요할 것으로 판단된다.

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Germination Characteristics of Medicinal Crop Adenophora triphylla var. japonica Hara as Affected by Seed Disinfection and Light Quality (종자 소독처리와 광질에 따른 약용작물 잔대 종자의 발아특성)

  • Lee, Hye Ri;Kim, Hyeon Min;Jeong, Hyeon Woo;Oh, Myung Min;Hwang, Seung Jae
    • Journal of Bio-Environment Control
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    • v.28 no.4
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    • pp.404-410
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    • 2019
  • This study was performed to investigate the seed morphological characteristics and dormancy type of Adenophora triphylla var. japonica Hara that high valued medicinal crop and to select the disinfectants and light quality for germination rate improvement. The seed disinfection was carried out using distilled water (control), NaClO 4%, $H_2O_2$ 4%, and benomyl $500mg{\cdot}L^{-1}$. The light quality treatments were set to dark condition (control I), fluorescent lamp (control II), LEDs [red, blue, green, and combined RB LEDs (red:blue = 8:2, 6:4, 4:6, 2:8)] with a photoperiod of 12/12 (light/dark) and light intensity $150{\pm}10{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ photosynthetic photon flux density. Although the Adenophora triphylla var. japonica Hara seed was an underdeveloped embryo (E) and seed (S) with an embryo (E):seed (S) ratio of 0.4, it is germinated within 30 days, and seed moisture saturation was reached within 6 hours after immersion. After seed disinfection, the mold incidence rate was significantly inhibited, and the final germination rate was the highest at 87% in the benomyl seed disinfection. The final germination rate was the highest at 92% in the red light, and the mean daily germination was the lowest in the R2B8. Therefore, there is almost no dormancy in the Adenophora triphylla var. japonica Hara seed, and benomyl seed disinfectant and red light were effective in the improvement of germination rate. So it is considered to the high value of use for medicinal crop Adenophora triphylla var. japonica Hara cultivation.

Comparative Analysis of Detection Methods for Food-borne Pathogens in Fresh-cut Agricultural Materials (신선 농산물내 식중독균 검출 방법의 비교 분석)

  • Jang, Hye-Jeong;Kim, Hye-Jeong;Park, Ji-in;Yu, Sun-Nyoung;Park, Bo-Bae;Ha, Gang-Ja;Ahn, Soon-Cheol;Kim, Dong-Seob
    • Journal of Life Science
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    • v.31 no.1
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    • pp.10-16
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    • 2021
  • The consumption of fresh-cut agricultural materials is increasing due to increased public interest in health and the increase of single-person households. Most fresh-cut agricultural materials can be eaten without heating, thus easily exposing the consumer to food-borne pathogens. As a result, food-borne diseases are increasing worldwide. In the analysis of food-borne pathogens, it is important to detect the strains, but this is time consuming and laborious. Alternative detection methods that have been introduced, include polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE), which is performed without prior culturing. Samples of fresh-cut agricultural materials, such as vegetables, were analyzed by the culture-based method. In 129 samples, non-pathogenic Escherichia coli (3.9%), Bacillus cereus (31.8%), Clostridium perfringens (5.4%), Yersinia enterocolitica (0.8%), and enterohemorrhagic E. coli (0.8%) were detected. Eight samples contaminated with bacteria were randomly selected, further analyzed by PCR-DGGE, and compared with the culture-based method. Two cases detected non-pathogenic E. coli by PCR-DGGE only, despite a lack of detection by the culture method. It was supposed there was possibility of sample loss during its 10-fold dilution for appropriate cultivation. In the detection of high-risk food-borne pathogens, it was found that the detection limit was lower in PCR-DGGE than in the culture-based method (10 CFU/g). This suggests that PCR-DGGE can be alternatively used to detect strains. On the other hand, low-risk food-borne pathogens seem to have higher detection limits in PCR-DGGE. Consequentially, this study contributes to the improvement of food-borne pathogen detection and the prevention of its related-diseases in fresh-cut agricultural materials.

Analysis of Major Factors related to the Generation of Fine Particulate Matter in Hanwoo Manure Composting Facilities (한우분뇨 퇴비화시설에서의 미세 입자상물질 발생 주요인자 분석)

  • Jeong, Kwang-Hwa;Park, Hoe-Man;Lee, Dong-Jun;Kim, Jung-Kon;Lee, Dong-Hyun;Kim, Da-Hye
    • Journal of the Korea Organic Resources Recycling Association
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    • v.28 no.4
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    • pp.53-68
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    • 2020
  • The concentrations of ammonia, hydrogen sulfide and fine dust were measured in the compost facility of a full-time Hanwoo breeding farms. The experiments were conducted in stack type composting facility(T1) and mechanical-stirred composting facilities(T2, T3). In the stack type composting facility, the highest temperature of compost pile was 46℃, and in the two mechanical-stirred composting facilities, it rose to 63℃ and 68℃, respectively. The concentrations of PM2.5 at T1, T2 were 15 ㎍/㎥ and 5~10 ㎍/㎥, respectively. And the concentration of PM2.5 at T3 was below 10 ㎍/㎥. The highest concentration of ammonia generated at T1 was 4 ppm, but no hydrogen sulfide was detected. The ammonia concentrations at T2 and T3 were 3 ppm and 4 ppm, respectively. However, hydrogen sulfide was not detected in both facilities. At T3, the ammonia concentration increased to 65 ppm at the point where the compost was stirred with a mechanical agitator. During composting period, the pH of the compost pile decreased from 9.06 to 8.94 and then increased to 9.14 as the composting period elapsed. The NaCl content of compost was 0.09% after composting process was complete. Moisture content of compost decreased from 65.9% to 62% as composting progressed. As composting proceeded, the content of volatile solids decreased from 65.6% to 64.7% and the content of TKN decreased from 1.327% to 1.095%.

Antioxidant Properties of 7 Domestic Essential Oils and Identification of Physiologically Active Components of Essential Oils against Candida albicans (식물정유 7종의 항산화능 분석 및 Candida albicans 생장 억제 정유의 생리활성 성분 구명)

  • LEE, Sang-Youn;LEE, Da-Song;CHO, Seong-Min;KIM, Jong-Chan;PARK, Mi-Jin;CHOI, In-Gyu
    • Journal of the Korean Wood Science and Technology
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    • v.49 no.1
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    • pp.23-43
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    • 2021
  • In this study, we selected two essential oils, Citrus unshiu and Cinnamomum cassia with superior antioxidant effects from the essential oils of 7 wild plants in South Korea and examined their antimicrobial activity against Candida albicans, which causes dermatitis to identify the antimicrobial components in the essential oils. As a result of measuring DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity, SC50 value of the Citrus unshiu essential oil was 0.010 mg/mL, while for the Cinnamomum cassia essential oil, SC50 value was 0.09 mg/mL. In addition, when ABTS (2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonic acid) radical scavenging activity was measured, SC50 value of the Citrus unshiu essential oil was 0.09 mg/mL, while for the Cinnamomum cassia essential oil, it was 0.06 mg/mL, exhibiting high antioxidant activity. For the minimum inhibitory concentration (MIC), the essential oil of Cinnamomum cassia was 1.25 mg/mL and that of Citrus unshiu was 5 mg/mL, demonstrating a high antimicrobial activity of the Cinnamomum cassia essential oil. Through the thin layer chromatography (TLC) bioassay, we assessed the antimicrobial activity against C. albicans according to the fraction components of the two essential oils. Also, by using preparative TLC (prep. TLC), we obtained the active fractions, and by performing GC/MS analysis of the components with the same Rf value, we identified the antimicrobial-active components. As a result, the main components having antioxidant and antimicrobial activities were cinnamyl acetate, eucalyptol, linalool, and citral of the Cinnamomum cassia essential oil and linalool from the Citrus unshiu essential oil. Also, based on the analysis of the fractional components that showed antioxidant and antimicrobial activities in both of the two essential oils, it was found that linalool has antioxidant activity, while cinnamyl acetate, eucalyptol, citral, and geranyl acetate have antioxidant and antimicrobial activities.

A Study on the Digital Decipherment of the Goguryeo Stele in Chungju (충주고구려비(忠州高句麗碑) 디지털 판독의 성과와 고찰)

  • JO, Younghoon;KWON, Dakyung;AHN, Jaehong;KO, Kwangeui
    • Korean Journal of Heritage: History & Science
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    • v.54 no.2
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    • pp.240-253
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    • 2021
  • Various decipherment technologies, including manual rubbing, have been continuously applied to the Goguryeo Stele in Chungju. However, an official document for advanced decipherment is required as there remain characters to be deciphered. This study focuses on interdisciplinary digital decipherment using digital visualization results based on reflectance transformation imaging and three-dimensional scanning. On that basis, the joint decipherment document in 2019 is classified into eight types according to character changes from 1979 to 2000, and decipherment achievements are discussed. Important outcomes of the joint decipherment document include a new interpretation of four existing characters and the identification of 28 new characters. Additionally, 68 characters on the front face and 20 on the left face, which are listed differently in previous decipherment documents, are determined to be a single character through a consensus process. Compared to the previous decipherment document, the "decision" character is increased by a total of 89 characters (22.6%), and the "different opinion" character is decreased by 126 characters (32.0%). Thus, this digital decipherment greatly contributes to the reexamination of the Goguryeo Stele in Chungju and complements the previous decipherment document through reflectance transformation imaging and three-dimensional scanning. However, continuous research is necessary to enhance decipherment rates, since 123 characters (31.3%) are yet to receive decipherment. In the future, decipherment advancement regarding the Goguryeo Stele in Chungju should be based on convergence research between the humanities and science. Furthermore, it seems that researchers must make constant efforts to apply new imaging analysis technology and to develop customized technology for decipherment.

Effects of Supplementation of Spent Mushroom(Flammulina velutipes) Substrates on the in vitro Ruminal Fermentation Characteristics and Dry Matter Digestibility of Rye Silage (호밀 사일리지 제조 시 팽이버섯 수확 후 배지 첨가수준이 in vitro 반추위 발효특성 및 건물소화율에 미치는 영향)

  • Kang, Han-Byeol;Cho, Woong-Ki;Cho, Soo-Jeong;Lee, Shin-Ja;Lee, Sung-Sill;Moon, Yea-Hwang
    • Journal of agriculture & life science
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    • v.51 no.5
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    • pp.91-101
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    • 2017
  • The in vitro experiment was conducted to ensure the supplemental level of spent Flammulina velutipes mushroom substrates(SMS) as an energy source in manufacturing of rye silage. Rye harvested at heading stage was ensiled with spent mushroom substrates of 0%(Control), 20%(R-20), 40%(R-40) and 60%(R-60) as fresh matter basis for 6week. The rumen fluid for preparation of in vitro solution was collected from two cannulated Holstein bulls fed a 40:60 concentrate:timothy diet. The experiment was conducted by 3, 6, 9, 12, 24, and 48 hrs of ncubation time with 3 replications. The silages were evaluated fermentation characteristics and dry matter digestibility(DMD) in vitro. The pH of in vitro solution was inclined to decrease with elapsing the incubation time, and that of the R-60 was significantly(p<0.05) lower than the other treatment at 48 hr of incubation. The microbial growth in vitro was inclined to increase with elapsing the incubation time, and that of the R-20 was significantly(p<0.05) greater than the Control at 48 hr of incubation. Gas production was greater(p<0.05) in the Control than the other treatments at 48 hr of incubation. In vitro dry matter digestibility(IVDMD) was higher with increasing the supplemental level of SMS, and was significantly(p<0.05) lower in the Control compared with other treatments throughout whole incubation time. The IVDMD for R-60 was the highest(p<0.05) among treatments at 24 hr and 48 hr of incubation. Considering of above results and the availability of SMS, SMS could be supplemented by 60% in fresh matter basis for rye silage fermentation.

A Study Covering the Comparative Analysis of Educational Systems in Major Countries for Regular Cybersecurity Education (사이버보안 정규교육화를 위한 주요국 교육체계 비교분석 연구)

  • YOO, Jiyeon
    • The Journal of the Convergence on Culture Technology
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    • v.7 no.1
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    • pp.397-405
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    • 2021
  • With the recent phenomenon of the Intelligence Information Society, the cyber security paradigm has begun to change. In particular, the increase of the interconnectedness of the hyperlinked society has extended the scope of damage that can be caused by cyber threats to the real world. In addition to that, it can also be a risk to any given individual who could accompany a crisis that has to do with public safety or national security. Adolescents who are digital natives are more likely to be exposed to cyber threats, which is mainly due to the fact that they are significantly more involved in cyber activities and they also possess insufficient security comprehension and safety awareness. Therefore, it is necessary to strengthen cyber security capabilities of every young individual, so that they can effectively protect themselves against cyber threats and better manage their cyber activities. It examines the changes of the security paradigm and the necessity for cyber security education, which is in direct accordance to the characteristics of a connected society that further suggests directions and a basic system of cyber security education, through a detailed analysis of the current state of Domestic and Overseas Cyber Security Education. The purpose of this study was to define cybersecurity competencies that are necessary within an intelligent information society, and to propose a regular curriculum for strengthening cybersecurity competencies, through the comparison and meticulous analysis of both domestic and overseas educational systems that are pertinent to cybersecurity competencies. Accordingly, a cybersecurity competency system was constructed, by reflecting C3-Matrix, which is a cyber competency system model of digital citizens. The cybersecurity competency system consists of cyber ethics awareness, cyber ethics behavior, cyber security and cyber safety. In addition to this, based on the basic framework of the cybersecurity competency system, the relevant education that is currently being implemented in the United States, Australia, Japan and Korea were all compared and analyzed. From the insight gained through the analysis, the domestic curriculum was finally presented. The main objective of this new unified understanding, was to create a comprehensive and effective cyber security competency curriculum.

Natural Baseline Groundwater Quality in Shingwang-myeon and Heunghae-eup, Pohang, Korea (포항시 신광면 및 흥해읍 일대 지하수의 배경수질 연구)

  • Lee, Hyun A;Lee, Hyunjoo;Kwon, Eunhye;Park, Jonghoon;Woo, Nam C.
    • The Journal of Engineering Geology
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    • v.30 no.4
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    • pp.469-483
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    • 2020
  • The results of long-term groundwater level and quality monitoring can be used not only as the basic data for evaluating the impact of various disasters including climate change and establishing responses, but also as key data for predicting and managing geological disasters such as earthquakes. Some countries use groundwater level and quality monitoring for researches to predict earthquakes and to assess the impacts of the earthquake disaster. However, a few cases in Korea report on individual groundwater quality factors (i.e., dissolved ions) observed before and after the earthquakes, being different from other countries. To establish the abnormality criteria for groundwater quality in Pohang, groundwater samples were collected and analyzed five times from 14 agricultural or private wells existing in Shingwang-myeon and Heunghae-eup. As a result of the analysis, it was found that Ca2+ was the dominant cation in Shingwang-myeon, while Na+ was the dominant cation in Heunghae-eup. The elevated NO3- concentration in Shingwang-myeon is contributed to the agricultural activity in the area. A high concentration of Fe was detected in a well on Heunghae-eup; the concentration exceeded the drinking water standard by nearly 100 times. Relatively higher dissolved ions were observed in the groundwater of Heunghae-eup, and it is considered as the result of the flow velocity difference and water-rock reaction accompanying the difference in bedrock and sediment characteristics. The groundwater of Shingwang-myeon appeared to be most affected by the weathering of granite and silicates, while that of Heunghae-eup was mainly affected by the weathering of silicates and carbonate. The background concentrations (baselines) of groundwater Shingwang-myeon and Heunghae-eup was identified through the survey; however, the continuous monitoring is required to monitor the possible changes and the repeatability of seasonal variation.

Performance of a Molten Carbonate Fuel Cell With Direct Internal Reforming of Methanol (메탄올 내부개질형 용융탄산염 연료전지의 성능)

  • Ha, Myeong Ju;Yoon, Sung Pil;Han, Jonghee;Lim, Tae-Hoon;Kim, Woo Sik;Nam, Suk Woo
    • Clean Technology
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    • v.26 no.4
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    • pp.329-335
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    • 2020
  • Methanol synthesized from renewable hydrogen and captured CO2 has recently attracted great interest as a sustainable energy carrier for large-scale renewable energy storage. In this study, molten carbonate fuel cell's performance was investigated with the direct conversion of methanol into syngas inside the anode chamber of the cell. The internal reforming of methanol may significantly improve system efficiency since the heat generated from the electrochemical reaction can be used directly for the endothermic reforming reaction. The porous Ni-10 wt%Cr anode was sufficient for the methanol steam reforming reaction under the fuel cell operating condition. The direct supply of methanol into the anode chamber resulted in somewhat lower cell performance, especially at high current density. Recycling of the product gas into the anode gas inlet significantly improved the cell performance. The analysis based on material balance revealed that, with increasing current density and gas recycling ratio, the methanol steam reforming reaction rate likewise increased. A methanol conversion more significant than 90% was achieved with gas recycling. The results showed the feasibility of electricity and syngas co-production using the molten carbonate fuel cell. Further research is needed to optimize the fuel cell operating conditions for simultaneous production of electricity and syngas, considering both material and energy balances in the fuel cell.