• 한국유기농업학회지
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• 제19권3호
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• pp.291-308
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• 2011

This study was carried out to estimate carbon footprint and to establish of LCA of cherry-tomato production system. I have case study in cultivate cherry tomato (1 kg) calculate in carbon foot print. LCA carried out to estimate carbon foot print and to establish of LCI (life cycle inventory) database of cherry tomato production system. The data is from Research of Farmer's income in 2007 (RDA, 2008), and used Pass (4.1.3) program. The value of fertilizer, amount of pesticide input were show the environmental effect and direct emission. Carbon foot printing in agriculture guarantee the choice right th consumer th choose the row carbon goods. Its can make to strengthen of agriculture and food industry's reduction effort of $CO_2$. Nowadays consumer request food's safety and environment friendly process. Carbon foot printing needs consumer's relief and incentives.

• Nuclear Engineering and Technology
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• 제56권4호
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• pp.1254-1266
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• 2024

This study investigates the application of supercritical carbon dioxide (S-CO₂) direct-cycle micro modular reactors (MMRs) in primary frequency control (PFC), which is a scenario characterized by significant load fluctuations that has received less attention compared to secondary load-following. Using a modified GAMMA + code and a deep neural network-based turbomachinery off-design model, the authors conducted an analysis to assess the behavior of the reactor core and fluid system under different PFC scenarios. The results indicate that the acceptable range for sudden relative electricity output (REO) fluctuations is approximately 20%p which aligns with the performance of combined-cycle gas turbines (CCGTs) and open-cycle gas turbines (OCGTs). In S-CO₂ direct-cycle MMRs, the control of the core operates passively within the operational range by managing coolant density through inventory control. However, when PFC exceeds 35%p, system control failure is observed, suggesting the need for improved control strategies. These findings affirm the potential of S-CO₂ direct-cycle MMRs in PFC operations, representing an advancement in the management of grid fluctuations while ensuring reliable and carbon-free power generation.

• 한국유기농업학회지
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• 제20권2호
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• pp.161-172
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• 2012

This study was carried out to estimate carbon footprint and to establish of LCA of garlic production system. We have case study in cultivate garlic 1 kg calculate in carbon footprint. LCA carried out to estimate carbon footprint and to establish of LCI (life cycle inventory) database of garlic production system. The data is from Research of Farmer's income in 2010 (RDA, 2011), and used Pass (5.0.0) program. The value of fertilizer, amount of pesticide input were shown the environmental effect and direct emission. Carbon footprint in agriculture guarantees the choice right the consumer to choose the lower carbon goods. Its can make to strengthen of agriculture and food industry's reduction effort of $CO_2$. Nowadays consumer requests food's safety and environment friendly process. Carbon footprint also needs consumer's relief and incentives.

• 한국건축시공학회지
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• 제22권2호
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• pp.137-148
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• 2022

본 연구는 레디믹스트 콘크리트의 환경성적표지 현황 조사와 이를 통한 레디믹스트 콘크리트 규격, 생애주기, 권역별 탄소배출량 특성 분석을 목적으로 한다. 이를 위해 콘크리트 산업의 탄소배출량 산정이 요구되고 있는 관련 인증제도를 분석하고, 레디믹스트 콘크리트 제품의 탄소배출량 현황분석을 위해 전과정평가 기법에 기반한 EPD 인증을 받은 제품군을 대상으로 하여 레디믹스트 콘크리트의 활성화 정도를 분석하였다. 또한 레디믹스트 콘크리트 제품의 생애주기별 탄소배출량 분석, 규격별 탄소배출량 분석, 권역별 탄소배출량 분석을 수행하여 각 특성에 따른 탄소배출량 추이를 검토하였다. 분석결과 생애주기별 탄소배출량은 제조전단계가 99% 수준을 나타냈으며, 18MPa에서 40MPa로 증가할수록 탄소배출량도 증가하는 추세를 보였다. 단, 동일 규격이라고 하더라도 수도권의 탄소배출량이 남부지역 대비 높은 탄소배출량을 나타냈다.

• 한국지구과학회지
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• 제25권8호
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• pp.684-696
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• 2004

이 연구의 목적은 6명의 예비교사들을 대상으로, 탄소 순환을 이해하는데 적용되는 개념들을 조사하여 지구시스템에 관련된 개념은 무엇인가를 알아보고, 탄소 순환에 대해서 시스템 사고를 적절히 수행하고 잇는지를 조사하는 것이었다. 연구방법은 고등학교 지구과학에서 다루고 있는 “지구의 구성” 단원 중 ‘탄소 순환’과 관련된 질문을 통해, 예비교사들이 진술한 내용을 분석하여 개념의 특성을 조사하였다. 이를 근거로 지구시스템에 관련된 개념을 구성요소로 하여 인과지도를 작성한 수, 시스템 사고의 관점에서 분석하였다. 연구결과는 다음과 같다, 첫째ㅡ 탄소 순환을 이해하는데 적용된 개념들 중 지구시스템에 대한 관련개념은 모두 42개가 나타났다, 그 중 기권 관련개념은 15개, 생물권 관련개념은 11개, 수권 관련개념은 9개였으며, 암석권 관련개념은 7개였다. 둘째, 인과지도에서 피드백 순환고리는 A와 F 예비교사들에게 2개와 1개가 완성되었으나, A예비교사에게서 완성된 2개의 피드백 순환고리 중 1개는 비과학적 개념연결에 근거하였다. 결론적으로, 연구에 참가한 6명의 예비교사들은 탄소 순환과 관련하여 지구시스템에서 암석권에 대한 이해가 낮으며, 4명은 시스템 사고가 수행되지 않았고, 2명은 시스템 사고를 수행하였으나, 그 수준은 높지 않았다.

• Korean Chemical Engineering Research
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• 제56권4호
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• pp.561-567
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• 2018

본 연구에서는 리튬이온전지 실리콘 음극소재의 사이클 안정성 향상을 위해 실리콘/탄소 음극소재의 전기화학적 특성을 조사하였다. Tetraethyl orthosilicate (TEOS) 로부터 스토버법 및 마그네슘 열 환원법을 통하여 다공성 실리콘을 제조하고, 제조된 다공성 실리콘과 피치의 질량비에 따라 실리콘/탄소 음극소재를 제조하였다. 실리콘/탄소 음극소재의 물리적 특성은 XRD와 TGA를 통해 분석하였다. 1.0 M $LiPF_6$ (EC : DEC = 1 : 1 vol%) 전해액에서 실리콘/탄소 음극소재의 충 방전 사이클, 율속, 순환전압전류, 임피던스 테스트를 통해 전기화학적 특성을 조사하였다. 제조된 실리콘/탄소 음극소재 실리콘 : 탄소 = 5 : 95 일때 453 mAh/g의 향상된 용량을 나타내었으며, 사이클 성능 또한 두 번째 사이클 이후 30 사이클까지 매우 우수한 사이클 안정성을 나타냄을 확인하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제31권6호
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• pp.723-728
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• 2007

In order to evaluate the performance of carbon dioxide cycle with a sub-cooling loop. a simulation system was developed to predict the steady state of $CO_2$ trans-critical cycle. Mathematical models are derived to describe the relationships between the system's coefficient of performance and other operating parameters The mathematical models are based entirely on the basic mass and energy conservation law and thermodynamic and transport properties of carbon dioxide A parametric study has been conducted in order to investigate the effect of sub-cooling loop and various operating conditions on the cycle performance. An optimal mass fraction of a refrigerant flowing through sub-cooling cycle existed for the given evaporating temperature, high pressure and air inlet temperature through gas cooler.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.183-186
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• 2010

Advanced Railway countries are developing technologies of production and management for low-carbon and green growth of their railway industry to hold a dominant position under post-Tokyo protocol regime through integrated approach which uses environmental quantitative analysis of train life cycle by using LCA(Life Cycle Assessment). On the contrary, Korea railroad industry attempts to make an environmental improvement only for using regenerative energy and improvement in operating energy consumption through adapting reduction weight of material technology and etc. without systematic environmental analysis approaches such as comparing and analyzing energy consumption as well as GHG emission in each life cycle stages of train. Therefore, In this paper, low-carbon management and comprehensive environmental improvement for sustainable development of Korea railway industry through analyzing the result of life cycle analysis in abroad are suggested.

• Journal of Plant Biology
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• 제16권1_2호
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• pp.6-11
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• 1973

The utilization of acetate by Dunaliella tertiolecta was examined, and the detections and assays of the enzymes of the tricarboxylic acid cycle and the glyoxylate pathway were described. Acetate could not be utilized as a sole carbon source for the growth. The carboxyl carbon of acetate was incorporated more rapidly into CO2 than the methyl carbon. It was identified that malate, succinate, citrate and etc., were accumulated whne [U-14C] acetate was supplied to the cell free homogenate. The following enzyme activities were measured; acetothiokinase, isocitrate dehydrogenase, fumarase, malate dehydrogenase and aconitase. Though isocitratase, malate synthetase, succinate dehydrogenase and oxoglutarate dehydrogenase could not be detected, 14C from succinate was easily contributed to CO2 and cell component. The evidence suggested that the glyoxylate pathway was not operative and showed that the TCA cycle was the all important pathway in the oxidation of acetate to CO2 in Dunaliella.

• Steel and Composite Structures
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• 제17권2호
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• pp.185-198
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• 2014

Carbon-manganese steel A42 (French standards) is used in steam generator pipes of nuclear center and subject to low cycle fatigue (LCF) loads. In order to obtain the material LCF behavior, the tests are implemented in a hydraulic fatigue machine. The LCF plastic deformation and cyclic stress in macroscope have been influenced by the accumulated low cycle fatigue damage. The constitutive kinematic and isotropic hardening modeling is modified with coupling fatigue damage to describe the fatigue behavior. The improved model seems to be good agreement with the test results.