• Title/Summary/Keyword: Carbon cycle

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System Configuration Studies on Gas Turbine Combined Cycle Power Plants - Application to Processes for Carbon Capture System (가스 터빈 복합화력 발전 플랜트의 시스템 구성 제안 - CO2 포집 대안 별 비교 평가)

  • Kim, Seungjin;Choi, Sangmin
    • 한국연소학회:학술대회논문집
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    • 2013.06a
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    • pp.15-17
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    • 2013
  • In the design of combined cycle power plants, the design parameters considered mainly could be changed and added for performance evaluation with change on the design objective and method. Therefore, the design criteria considering the different objectives and type of power plant were needed. Thermodynamic and economic analyses of various types of gas turbine combined cycle power plants with demand on generation of power and heat and carbon capture system from high pressure flue gas have been performed to establish criteria for optimization of power plants.

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Development and Application of Instrument for Level Scale of the Systems Thinking Ability about Carbon Cycle (탄소 순환에 대한 시스템 사고 능력 수준 측정을 위한 검사도구 개발 및 적용)

  • Jeon, Jaedon;Lee, Hyundong;Lee, Hyonyong
    • Journal of The Korean Association For Science Education
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    • v.42 no.4
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    • pp.397-415
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    • 2022
  • As the global warming problem becomes serious, the need for carbon cycle education in school is increasing. Adopting systems thinking ability is needed to understand the carbon cycle systematically. Furthermore, under the rapid change of environment, society, and economy, systems thinking ability is being emphasized as it can strengthen the competencies of students who will be leading the future society. The purposes of this study are as follows: first, is developing the systems thinking instrument for the carbon cycle and the rubric for analysis of systems thinking instrument. The second is analyzing the systems thinking ability of students using the developed instrument and rubric. In order to perform this study, previous studies related to the carbon cycle and systems thinking education were analyzed. Based on the analysis results, the systems thinking instrument for the carbon cycle and rubric were developed. The systems thinking ability was analyzed by implementing the developed instrument and rubric to 172 high school and university students. The results of this study are as follows: first, the systems thinking instrument for the carbon cycle was developed, and a rubric utilization guide was constructed. The instrument and rubric were modified through pilot study for middle school students producing expert opinion in relation to systems thinking and carbon cycle. Second, the systems thinking ability of students was analyzed. Consequently, students had systems thinking ability fully at a low level, such as identifying the variables related to the carbon cycle. However, it was shown that they lacked the systems thinking ability at a high level, such as time delay and feedback processes. The importance of the carbon cycle has been increasing since the global warming is the most pressing issue and significant environmental problem facing us today. Application of the systems thinking ability can contribute to understanding these complex problems and finding fundamental solutions.

A Study on Low-Cycle Fatigue Behavior at Elevated Temperature of High Carbon Steel Used For Structural Purpose (構造용高炭素鋼材 의 高溫 低 사이클 피勞擧動 에 關한 硏究)

  • 옹장우;김재훈
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.6 no.2
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    • pp.101-106
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    • 1982
  • This study was undertaken to determine tensile properties and low-cycle fatigue behavior of 0.6%C high carbon steel used of structural purposes at temperatures up to 500.deg.C. In the low-cycle fatigue test the upper limit was decided by elongation(i.e. the total strain range), while the lower limit was defined by the load (i.e. zero load). The following results were obtained. Both, the ultimate tensile strength and low-cycle fatigue resistance attain the maximum values near 250.deg.C. Above this temperature the values decrease rapidly as the temperature increases. The low-cycle fatigue resistance decreases whenever there is an increase of the total strain range. Because the hardness of cycle fatigued specimen correlates cyclic hardening and cyclic softening, therefore the hardness of cycle fatigued specimen is smaller than that of the nonfatigued specimen at room temperature and 500.deg.C but much larger than the hardness of the nonfatigued specimen near 250.deg.C.

Simulation Study on the Performance Improvement of a Transcritical Carbon Dioxide Cycle (초월임계 이산화탄소 사이클의 성능향상에 관한 시뮬레이션 연구)

  • 조홍현;김용찬;서국정
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.16 no.2
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    • pp.158-166
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    • 2004
  • The performance of a heat pump using $CO_2$ is predicted and analyzed by using a cycle simulation model developed in this study. Cycle simulations are conducted by varying design parameters and operating conditions with the applications of advanced techniques to improve system performance. The applied systems in the simulations are internal heat exchanger, expander, and 2-stage compression with intercooling. As a result, the applications of advanced techniques improve the heating and cooling performances of the transcritical $CO_2$ cycle by 8∼26% and 20∼30%, respectively, over the basic cycle.

A Study on the Analysis of Carbon Emissions by Transportation Distance of Building Materials (건축자재 운송거리에 따른 탄소배출량 분석에 관한 연구)

  • Kim, Hyeon-Suk;Tae, Sung-Ho;Lim, Hyo-Jin;Jang, Hyeong-Jae;Lee, Chung-Won
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2022.11a
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    • pp.125-126
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    • 2022
  • As environmental problems around the world become serious, Korea has also raised the greenhouse gas reduction in the building sector to 32.8% compared to 2018, and efforts to reduce carbon in buildings are expanding. Recently, research is being actively conducted to reduce carbon in the long term by expanding the scope of greenhouse gas indirect emissions (Scope3), and even within the domestic Green Standard for Energy and Environmental Design(G-SEED) by quantitatively evaluating the environmental impact of buildings during the entire life cycle. However, it is difficult to accurately evaluate the carbon emission of the transportation process by assuming the material transport distance in the evaluation of the Life Cycle Assessment(LCA). Therefore, in this study, the main building materials of the building were selected through case evaluation and the carbon emission of the material transport process was derived based on the actual transport distance, and this was compared and analyzed with the theoretical LCA results.

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Global Carbon Budget Changes under RCP Scenarios in HadGEM2-CC (HadGEM-CC 모델의 RCP 시나리오에 따른 전지구 탄소수지 변화 전망)

  • Heo, Tae-Kyung;Boo, Kyung-On;Shim, Sungbo;Hong, Jinkyu;Hong, Je-Woo
    • Atmosphere
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    • v.25 no.1
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    • pp.85-97
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    • 2015
  • This study is to investigate future changes in carbon cycle using the HadGEM2-Carbon Cycle simulations driven by $CO_2$ emissions. For experiment, global carbon budget is integrated from the two (8.5/2.6) representative concentration pathways (RCPs) for the period of 1860~2100 by Hadley Centre Global Environmental Model, version 2, Carbon Cycle (Had-GEM2-CC). From 1985 to 2005, total cumulative $CO_2$ amount of anthropogenic emission prescribed as 156 GtC. The amount matches to the observed estimates (CDIAC) over the same period (136 GtC). As $CO_2$ emissions into the atmosphere increase, the similar increasing tendency is found in the simulated atmospheric $CO_2$ concentration and temperature. Atmospheric $CO_2$ concentration in the simulation is projected to be 430 ppm for RCP 2.6 at the end of the twenty-first century and as high as 931 ppm for RCP 8.5. Simulated global mean temperature is expected to rise by $1.6^{\circ}C$ and $3.5^{\circ}C$ for RCP 2.6 and 8.5, respectively. Land and ocean carbon uptakes also increase in proportion to the $CO_2$ emissions of RCPs. The fractions of the amount of $CO_2$ stored in atmosphere, land, and ocean are different in RCP 8.5 and 2.6. Further study is needed for reducing the simulation uncertainty based on multiple model simulations.

A Study on Analysis and Assessment of the LCCO2 Emissions for Building Construction by Using the Life Cycle Assessment Methodology (전과정평가 방법론을 이용한 건물의 전과정 탄소 배출량 평가 및 분석에 관한 연구)

  • Cho, Su-Hyun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2016.05a
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    • pp.259-260
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    • 2016
  • Recently, world-wide focusing on the interest for the reduction of greenhouse gas emissions associated with climate change and global warming, South Korea also has set up a national greenhouse gas reduction target and action plans seeking to achieve them. In particular, in the construction area, to encourage green building certification of the building and carbon labeling acquisition of building products, in order to reduce the environmental impact caused by the industrial activities have been in steady efforts. Therefore, this study estimates the life cycle carbon footprint of building construction materials applied to carbon emissions reduction technology and analyzes the results. Through the CO2 emissions analysis in construction phase and maintenance phase of the building, it provides basic resource for future research expansion and establishes a step-by-step whole life cycle carbon emissions reduction plan in new construction and existing buildings.

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Effect of simulated double cycle welding on HAZ microstructure for HSLA steels

  • El-Kashif, Emad F.;Morsy, Morsy A.
    • Advances in materials Research
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    • v.7 no.3
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    • pp.195-201
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    • 2018
  • High Strength low alloy steels containing various levels of C, Nb and Mn were used and for each of which, a simulated double thermal cycle was applied with the same first peak temperature and different second peak temperatures to produce HAZ microstructure corresponding to multi-pass weld. Effect of double cycle second temperature on the microstructure was observed and compared with single cycle results obtained from previous works, it was found that the percentage of martensite austenite constituent (MA) increases by Nb addition for all steels with the same Mn content and the increase in Mn content at the same Nb content shows an increase in MA area fraction as well. MA area fraction obtained for the double cycle is larger than that obtained for the single cycle for all steels used which imply that MA will have great role in the brittle fracture initiation for double cycle and the inter-pass temperature should be controlled for medium and high-carbon Mn steel to avoid large area fraction of MA. The beneficial effects of Niobium obtained in single pass weld were not observed for the double cycle or multi pass welds.

Estimation of Carbon Emissions and Energy Self-Sufficiency in Sewage Treatment plant's Improvement by using Life Cycle Management Tool (LCM 기법을 이용한 하수처리장 개선에 따른 탄소배출량 및 에너지 자립율 평가)

  • Moon, Jin-Young;Park, Ji-Hyoung;Hwang, Yong-Woo;Park, Kwang-Ho
    • Journal of Korean Society of Water and Wastewater
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    • v.27 no.2
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    • pp.223-232
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    • 2013
  • In this study, carbon emissions and energy consumption were evaluated to establish a design strategy which has low energy consumption and carbon emission production, by using life cycle energy (LCE) and life cycle $CO_2(LCCO_2)$ calculation methods in life cycle management(LCM) tools. After improvement design projects, the energy consumption and $CO_2$ emission were calculated and compared in three sewage treatment plants (STPs), which are A STP, B STP, and C STP. The reduction of carbon emissions was 28,020.1 ton $CO_{2-}e/yr$, 37,399.6 ton $CO_{2-}e/yr$ and 8,788.3 ton $CO_{2-}e/yr$, respectively. Production of energy was 792 TOE/yr, 1,235 TOE/yr and 1,023 TOE/yr, respectively. As a result, the estimation of energy and energy self-sufficiency was 5.1 %, 14.5 % and 23.5 %, respectively. The result of this study shows the LCM can be contributed to establish strategy for energy and carbon emission reduction in sewage treatment plants.

Analysis of Secondary School Students' System Thinking on the Cycle of Matter in Earth System: Considering the Impact of Human Activity on the Cycle (지구 시스템 내 물질 순환에 대한 중·고등학교 학생들의 시스템 사고 분석: 인간의 활동이 순환에 미치는 영향을 고려하여)

  • Oh, Hyunseok;Lee, Kiyoung;Kim, Kwonjung
    • Journal of Science Education
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    • v.45 no.3
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    • pp.275-291
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    • 2021
  • The purpose of this study is to analyze the level and characteristics of system thinking of middle and high school students on cycle of matter in the Earth system considering the impact of human activities on the cycle. For this purpose, we developed items for assessment and assessment rubric through the analysis of 2015 revised curriculum and applying systems thinking, respectively. Middle and high school students who participated in the Korea Earth Science Olympiad were the subjects of this study. The level of system thinking was determined using the assessment rubric for student responses collected using items for assessment. The characteristics of system thinking were identified using word analysis. Based on these, the improvement of the curriculum considering the impact of human activities was discussed. The results of the study are as follows: first, the system thinking level of most secondary school students was low in identifying or classifying system elements for matter cycle, and high levels, such as system relationship or generalization of patterns, were found to be relatively small. It was found that students had a higher level of system thinking in the carbon cycle than in the water cycle. Second, in terms of the characteristics of system thinking about water cycle, water was recognized as a major system element and mainly related with evaporation between atmosphere and other system elements. Whereas, in the carbon cycle, carbon dioxide was regarded as a major system element, and photosynthesis and respiration were represented in relation with the biosphere. Third, for education considering the impact of human activities on the matter cycle in the Earth system, it is proposed improving the curriculum considering the socio-ecological system by extending the existing earth system.