• Carbon letters
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• 제9권4호
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• pp.298-302
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• 2008

Carbon blacks could be used as the filler for the electromagnetic interference (EMI) shielding. The poly vinyl alcohol (PVA) and polyvinylidene fluoride (PVDF) were used as the matrix for the carbon black fillers. Porous carbon blacks were prepared by $CO_2$ activation. The activation was performed by treating the carbon blacks in $CO_2$ to different degrees of burnoff. During the activation, the enlargement of pore diameters, and development of microporous and mesoporous structures were introduced in the carbon blacks, resulting in an increase of extremely large specific surface areas. The porosity of carbon blacks was an increasing function of the degree of burn-off. The surface area increased from $80\;m^2/g$ to $1142\;m^2/g$ and the total pore volume increased from $0.14073\;cc{\cdot}g^{-1}$ to $0.9343\;cc{\cdot}g^{-1}$. Also, the C=O functional group characterized by aldehydes, ketones, carboxylic acids and esters was enhanced during the activation process. The EMI shielding effectiveness (SE) of raw N330 carbon blacks filled with PVA was about 1 dB and those of the activated carbon blacks increased to the values between 6 and 9 dB. The EMI SE of raw N330 carbon blacks filled with PVDF was about 7 dB and the EMI SE increased to the range from 11 to 15 dB by the activation.

• Journal of Forest and Environmental Science
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• 제39권3호
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• pp.119-127
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• 2023

In this study, quantitative models were applied to case parks to estimate the carbon reduction by trees, which was compared and analyzed at the tree and park levels. At the tree level, quantitative models of carbon storage and uptake differed by up to 7.9 times, even for the same species and size. At the park level, the carbon reduction from quantitative models varied by up to 3.7 times for the same park. In other words, carbon reduction by quantitative models exhibited considerable variation at the tree and park levels. These differences are likely due to the use of different growth environment coefficients and annual diameter at breast height growth rates and the overestimation of carbon reduction due to the substitution of the same genus and group model for each tree species. Extending the annual carbon uptake per unit area of the case park to the total park area of Chuncheon a carbon uptake ranging from a minimum of 370.4 t/yr and a maximum of 929.3 t/yr, and the difference can reach up to 558.9 t/yr. This is equivalent to the carbon emissions from the annual household electricity consumption of approximately 2,430 people. These results suggest that the indiscriminate application of quantitative models to estimate carbon reduction in urban trees can lead to significant errors and deviations in estimating carbon storage and uptake in urban greenspaces. The findings of this study can serve as a basis for estimating carbon reduction in urban greening research, projects, and policies.

• Environmental Engineering Research
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• 제22권3호
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• pp.237-244
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• 2017

At present, in India, handling of solid waste has become a major challenge for the municipal authorities. Composting of solid waste, especially organic waste, can be one of the solutions to tackle the issue of handling solid waste. The present study is focused on agitated piles composting of flower waste (FW). Five combinations of FW with dry leaves (DL) and cow dung (CD) were prepared to conduct the study. Significant changes were observed due to the addition of bulking agent. The bulking material helps to reduce the production of leachate and also to maintain the aerobic condition within the piles. The reduction of total organic carbon was 21% in FW composting which increased by 36.48% during the composting of FW on addition of DL and CD. On the 120th day of composting, the pH of pile five (70 kg FW + 20 kg CD + 15 kg DL) was 7.33, electrical conductivity 2.77 mS/cm, total organic carbon 26.9%, total nitrogen 2.2%, and C:N ratio was 12. Appropriate proportion of waste mixture played an important role in providing favorable conditions for the microbial transformation of flower waste to stabilized compost. Finally, FW with the combination of CD and DL was found to be successful during pile composting.

• 한국대기환경학회지
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• 제30권5호
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• pp.461-476
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• 2014

Continuous Water-Soluble Organic Carbons (WSOC) by the Particle Into Liquid Sampler - Total Organic Carbon (PILS-TOC) analyzer were measured at the Seoul intensive monitoring site from June 17 through July 5 in 2014. In addition, the 24 hour integrated PM2.5 collected by Teflon and Quartz filters were analyzed for water soluble ions by Ion chromatography (IC), WSOC by TOC from water extracts, organic carbon (OC), elemental carbon (EC) by carbon analyzer using the thermal optical transmittance (TOT) method, and mass fragment ions (m/z) related to alkanes and PAHs (Poly Aromatic Hydrocarbons) by Gas Chromatography-Mass Spectrometer-Thermal Desorption (GC/MS-TD). Based on the statistical analysis, four different Carbonaceous Thermal Distributions (CTDs) from OCEC thermal-gram were identified. This study discusses the primary and secondary sources of WSOC based on the Classified CTD, organic mass fragments, and diurnal patterns of WSOC. The results provide knowledge regarding the origins of WSOC and their behaviors.

• 약학회지
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• 제41권5호
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• pp.622-628
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• 1997

Hepatic cirrhosis is a common response to chronic liver injury from many causes and is one of the most common cause of all deaths. This study was carried out to compare experimental hepatic cirrhosis in rats to understand this disease and to apply for the pharmacokinetics in disease state. Following three kinds of experimental models were induced; 1) Bile duct ligation/scission (BDL/S), 2) N, N-dimethylnitrosamine(DMN), 3) Carbon tetrachloride. The hepatic cirrhosis was characterized by examing the liver/body weight ratio, serum biochemical values, hydroxyproline content in liver and histopathological lesions in cirrhotic rat liver. The results are as follows : (1) In BDL/S, the liver was enlarged to 250% of normal liver. In contrast the liver was shrinked to 48% and 78% of the normal liver in DMN and carbon tetrachloride, respectively. (2) In carbon tetrachloride and BDL/S, the serum ALT, AST, ALP and total bilirubin levels were significantly increased to 200~300% of normal level, while ALT and total bilirubin levels were significantly increased in DMN group. (3) Hydroxyproline content in cirrhotic rat liver was significantly 200~500% higher than that of normal liver. (4) Nodular formation with fibrosis was observed in BDL/S, DMN, carbon tetrachloride induced cirrhotic rat liver.

• 자원ㆍ환경경제연구
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• 제31권3호
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• pp.419-449
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• 2022

본 연구에서는, 환경산업연관표 분석모형을 활용해, EU 탄소국경조정이 전면 도입될 경우의 국내 산업별 탄소국경조정 부담액 규모를 산정하고 국내 저탄소 정책 시행에 따른 산업별 부담액 변화를 비교 분석함으로써 기후변화 리스크에 대응한 중장기전략 수립에 시사점을 제시하고자 하였다. 분석 결과 EU 탄소국경조정 전면도입 정책충격에 따른 국내 산업 총부담액은 2030년 기준 약 8조 2,456억 원 규모로 예측되었다. 업종별 영향을 살펴보면 석유화학, 석유정제, 운송장비, 철강, 자동차, 전기/전자/정밀 산업으로 등 6대 주요 산업군에서 총탄소국경조정 총부담액의 84.3%를 차지하는 것으로 전망되었다. 그리고 저탄소 정책 시행에 따른 기술발전 및 에너지 전환을 가정한 복수의 정책 시나리오에서는 탄소국경조정 총부담액이 약 11.7%~15.0% 감소할 것으로 전망되었다. 본 연구의 주요 분석 결과는 탄소국경조정의 전면도입 확대에 따른 대응전략 수립을 특정 분야에 한정해 이행하는 것이 아니라, 종합적 접근 하에서 이뤄내 국가 경제 전반에 끼치는 부정적 영향을 최소화하고 새로운 성장동력을 발굴하는 기회의 창으로 활용할 필요가 있음을 시사하고 있다.

• Journal of Forest and Environmental Science
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• 제34권6호
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• pp.472-480
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• 2018

This study was conducted to estimate carbon storage in Quercus mongolica stands based on stand age class, and to provide basic data on the carbon balance of broad-leaved forests of Korea. The research was conducted at the experimental forest of Kangwon National University, Hongcheon-gun County, Gangwon-do Province, Korea. Three plots were set up in each of three Q. mongolica forest stands (III, V, and VII) to estimate the amount of carbon stored in Q. mongolica aboveground vegetation, coarse woody debris (CWD), organic layer, mineral soil, and litterfall. The carbon storage of the aboveground vegetation increased with an increase in stand age, while the carbon storage ratio of stems decreased. The carbon storage of the organic layer, CWD, and litterfall did not show any significant differences among age classes. In addition, the carbon concentration and storage in the forest soils decreased with depth, and there were no differences among age classes for any soil horizon. Finally, the total carbon storage in the III, V, and VII stands of Q. mongolica were 132.2, 241.1, and $374.4Mg\;C\;ha^{-1}$, respectively. In order to predict and effectively manage forest carbon dynamics in Korea, further study on deciduous forests with other tree species in different regions will be needed.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제17권10호
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• pp.2682-2700
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• 2023

To cope with the risks of climate change and promote the realization of carbon peaking and carbon neutrality, this paper first comprehensively considers the policy background, technical trends and carbon reduction paths of energy conservation and emission reduction in data center server industry. Second, we propose a computing power carbon efficiency of data center server, and constructs the carbon emission per performance of server (CEPS) model. According to the model, this paper selects the mainstream data center servers for testing. The result shows that with the improvement of server performance, the total carbon emissions are rising. However, the speed of performance improvement is faster than that of carbon emission, hence the relative carbon emission per unit computing power shows a continuous decreasing trend. Moreover, there are some differences between different products, and it is calculated that the carbon emission per unit performance is 20-60KG when the service life of the server is five years.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.423-423
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• 2005

A carbon nanotube-based nanoelectromechanical device in resonance is examined theoretically. Mechanical deflections are electrically induced and resonantly excited at the fundamental frequency in cantilevered carbon nanotube. The electrically conducting elastic beam with van der Waals interactions at the tip is used for the modeling of the carbon nanotube device. Due to the elastic, electrical, and van der Waals interactions, the total energy of the system shows the unsymmetric two-well potentials. The predictions can be made that the device exhibits its nonlinear dynamic features in the two-well potentials. Also it is predicted that the fundamental frequency of the carbon nanotube device was changed by the nonlinear interactions induced by electrical and van der Waals potentials between carbon nanotube and ground surface of the device.

• Carbon letters
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• 제1권3_4호
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• pp.154-157
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• 2001

Composite adsorbents were prepared by mixing water plant sludge with phenolic resin having the ratio of 1 : 1, 1 : 2, and 1 : 3 respectively, curing from $100^{\circ}C$ to $170^{\circ}C$ under $N_2$ atmosphere, and then activating with $N_2$ at $700^{\circ}C$. Thermal property, specific surface area and morphology of the composite adsorbents as well as their precursors were measured by TGA, BET and SEM respectively. Removal efficiency of the composite adsorbents to ${NH_4}^+$ and TOC was compared with those of commercial zeolite and activated carbon. The adsorbents presented very promising TOC removal efficiency of 98%, which was identical level to that of commercial activated carbon while they displayed removal efficiency, only 32%, of ${NH_4}^+$. Therefore, this composite adsorbent considered as the alternative material of commercial activated carbon, used as an expensive removal agent of organic substances and THM in water treatment plant and it also suggested a possibility of practical application in other processes.