• Title, Summary, Keyword: Carbon

Search Result 23,614, Processing Time 0.09 seconds

Characteristics of Carbon Dioxide Destruction with a Plasma Torch and Effect of Additives (플라즈마 토치를 이용한 이산화탄소 분해특성과 첨가제의 영향)

  • Kim, Seong Cheon;Jeon, Jeong Hyeon;Chun, Young Nam
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.29 no.3
    • /
    • pp.287-296
    • /
    • 2013
  • To decompose carbon dioxide, which is a representative greenhouse gas, a plasma torch was designed and manufactured. To examine the characteristics of carbon dioxide decomposition via plasma discharge, a case wherein pure carbon dioxide was supplied and a case wherein methane and/or $TiCl_4$ were injected as additives were investigated and compared. The carbon dioxide and methane conversion rate, energy decomposition efficiency, produced gas concentration, carbon monoxide and hydrogen selectivity, carbon-black and $TiO_2$ were also investigated. The maximum carbon dioxide conversion rate was 28.9% when pure carbon dioxide was supplied; 44.6% when $TiCl_4$ was injected as am additive; and 100% percent when methane was injected as an additive. Therefore, this could be explained that the methane injection showed the highest carbon dioxide decomposition. Furthermore, the carbon-black and $TiO_2$ were compared with each commercial materials through XRD and SEM. It was found that the carbon-black that was produced in this study is similar for commercial materials. It was found that the $TiO_2$ that was produced in this study is suitable for photocatalyst and pigment because it has mixed anataze and rutile.

Challenges in Application of Remote Sensing Techniques for Estimating Forest Carbon Stock (원격탐사 기술의 산림탄소 축적량 추정적용에 있어서의 도전)

  • Park, Joowon
    • Current Research on Agriculture and Life Sciences
    • /
    • v.31 no.2
    • /
    • pp.113-123
    • /
    • 2013
  • The carbon-offset mechanism based on forest management has been recognized as a meaningful tool to sequestrate carbons already existing in the atmosphere. Thus, with an emphasis on the forest-originated carbon-offset mechanism, the accurate measurement of the carbon stock in forests has become important, as carbon credits should be issued proportionally with forest carbon stocks. Various remote sensing techniques have already been developed for measuring forest carbon stocks. Yet, despite the efficiency of remote sensing techniques, the final accuracy of their carbon stock estimations is disputable. Therefore, minimizing the uncertainty embedded in the application of remote sensing techniques is important to prevent questions over the carbon stock evaluation for issuing carbon credits. Accordingly, this study reviews the overall procedures of carbon stock evaluation-related remote sensing techniques and identifies the problematic technical issues when measuring the carbon stock. The procedures are sub-divided into four stages: the characteristics of the remote sensing sensor, data preparation, data analysis, and evaluation. Depending on the choice of technique, there are many disputable issues in each stage, resulting in quite different results for the final carbon stock evaluation. Thus, the establishment of detailed standards for each stageis urgently needed. From a policy-making perspective, the top priority should be given to establishinga standard sampling technique and enhancing the statistical analysis tools.

  • PDF

The Development of High Performance Nano-composites with Carbon Nanotube (카본나노튜브를 이용한 고성능 나노복합재료의 개발 동향)

  • Lee, Min-Kyung;Bae, Soo Bin;Park, Jong Kyoo;Lee, Seung Geol
    • Textile Coloration and Finishing
    • /
    • v.26 no.2
    • /
    • pp.71-78
    • /
    • 2014
  • This review paper is a state of the art report of the development of high performance nano-composites with carbon nanotube. We investigate the research and development (R&D) trends of high performance nano-composites with carbon nanotube by analyzing technical trends in research institutes and industry. We report the R&D and technology trends for the properties and applications of fabrication of hybrid composites with aligned carbon nanotubes, multifunctional fiber/carbon nanotube composites. We discuss the specific topics including unidirectional carbon nanotube, carbon nanotube forests, transfer-printing carbon nanotube technology, deposition of carbon nanotube by electrophoresis, vapor grown carbon fiber (VGCF), cup-stacked carbon nanotube, bucky paper and carbon nanotube yarns in this review paper.

Development of Carbon Composite Bipolar Plates for Vanadium Redox Flow Batteries

  • Lee, Nam Jin;Lee, Seung-Wook;Kim, Ki Jae;Kim, Jae-Hun;Park, Min-Sik;Jeong, Goojin;Kim, Young-Jun;Byun, Dongjin
    • Bulletin of the Korean Chemical Society
    • /
    • v.33 no.11
    • /
    • pp.3589-3592
    • /
    • 2012
  • Carbon composite bipolar plates with various carbon black contents were prepared by a compression molding method. The electrical conductivity and electrochemical stability of the bipolar plates have been evaluated. It is found that the electrical conductivity increases with increasing carbon black contents up to 15 wt %. When the carbon black contents are greater than 15 wt %, the electrical conductivity decreases because of a poor compatibility between epoxy resin and carbon black, and a weakening of compaction in the carbon composite bipolar plate. Based on the results, it could be concluded that there are optimum carbon black contents when preparing the carbon composite bipolar plate. Corrosion tests show that the carbon composite bipolar plate with 15 wt % carbon black exhibits better electrochemical stability than a graphite bipolar plate under a highly acidic condition. When the optimized carbon composite bipolar plate is applied to vanadium redox flow cells, the performance of flow cells with the carbon composite bipolar plate is comparable to that of flow cells with the graphite bipolar plate.

Theoretical study on electrical behavior of carbon chain inserted single-walled carbon nanotubes compared with Pt doped one

  • Cui, Hao;Zhang, Xiaoxing;Xiao, Hanyan;Tang, Ju
    • Carbon letters
    • /
    • v.25
    • /
    • pp.55-59
    • /
    • 2018
  • Carbon chain inserted carbon nanotubes (CNTs) have been experimentally proven having undergone pronounced property change in terms of electrical conductivity compared with pure CNTs. This paper simulates the geometry of carbon chain inserted CNTs and analyzes the mechanism for conductivity change after insertion of carbon chain. The geometric simulation of Pt doped CNT was also implemented for comparison with the inserted one. The results indicate that both modification by Pt atom on the surface of CNT and addition of carbon chain in the channel of the tube are effective methods for transforming the electrical properties of the CNT, leading to the redistribution of electron and thereby causing the conductivity change in obtained configurations. All the calculations were obtained based on density functional theory method.

Effect of Temperature on the Adsorption and Desorption Characteristics of Methyl Iodide over TEDA-Impregnated Activated Carbon

  • Park, Geun-Il;Kim, In-Tae;Lee, Jae-Kwang;Ryu, Seung-Kon;Kim, Joo-Hyung
    • Carbon letters
    • /
    • v.2 no.1
    • /
    • pp.9-14
    • /
    • 2001
  • Adsorption and desorption characteristics of methyl iodide at high temperature conditions up to $250^{\circ}C$ by TEDA-impregnated activated carbon, which is used for radioiodine retention in nuclear facility, was experimentally evaluated. In the range of temperature from $30^{\circ}C$ to $250^{\circ}C$, the adsorption capacity of base activated carbon decreased sharply with increasing temperature but that of TEDA-impregnated activated carbon showed higher value even at high temperature ranges. Especially, the desorption amount of methyl iodide on TEDA-impregnated carbon represented lower value than that on unimpregnated carbon. The breakthrough curves of methyl iodide in the fixed bed packed with base carbon and TEDA-impregnated activated carbon at high temperature were compared. TEDA-impregnated activated carbon would be applicable to adsorption process up to $150^{\circ}C$ for the removal of radioiodine in a nuclear facility.

  • PDF

Erosion Behavior of SiC Coated C/C Composites with Condition of Combustion Test

  • Joo, Hyeok-Jong;Min, Kyung-Dae;Lee, Jae-Won
    • Carbon letters
    • /
    • v.4 no.3
    • /
    • pp.133-139
    • /
    • 2003
  • Carbon/carbon composites are ideal candidates for a number of aerospace applications including structural materials for advanced vehicles, leading edges, structures of re-entry and hypersonic vehicles and propulsion systems. One serious defect for such application of the carbon/carbon composites is their poor oxidation resistance in high temperature oxidizing environments. SiC coating was employed to protect the composites from oxidation. It is mechanically and chemically stable under extreme thermal and oxidative environments, provides good adhesion to the substrate, and offers good thermal shock resistance. The SiC layer on the nozzle machined from the carbon/carbon composites was formed by pack-cementation method. Then, erosion characteristic of SiC coated carbon/carbon nozzle was examined by combustion test using a liquid rocket motor. The erosion rates were measured as function of combustion pressure, ratio of oxygen to fuel, combustion time, density of the composites and geometry of reinforced carbon fibre in the composites. The morphology change of the composites after combustion test was investigated using SEM and erosion mechanism also was discussed.

  • PDF

Reaction Rates for the Oxidation of Pitch based Carbon Fibers in Air and Carbon Dioxide Gas

  • Roh, Jae-Seung
    • Carbon letters
    • /
    • v.4 no.4
    • /
    • pp.185-191
    • /
    • 2003
  • Two types of carbon fiber based high modulus- and isotropic-pitch were exposed to isothermal oxidation in air and $CO_2$ gas and the weight change was measured by TGA apparatus. The kinetic equation was introduced $f=1-{\exp}(-at^b)$ and the constant b was obtained in the range of 1.02~1.68 for the isotropic fiber and obtained 0.91~1.93 for the high modulus fiber respectively. In considering the effect of the atmosphere for isothermal oxidation, the value of the constant b obtained in the carbon dioxide was higher than that obtained in the air. Therefore, it was found that the pitch based carbon fiber shows sigmoidal characteristic when it is oxidized in the carbon dioxide. In addition, it was also found that $k_f = 0.5$, which was reaction constant at f = 0.5, was a very useful parameter for evaluation of the oxidation reactivity of pitch based carbon fibers. According to the consideration, it is suggested that the conversion-time curves of the pitch based carbon fibers are correlated by normalized equation $f=1-{\exp}(-A{\tau}^B)$, where ${\tau}=t/t_f= 0.5$.

  • PDF

Carbon Stock Variation in Different Forest Types of Western Himalaya, Uttarakhand

  • Shahid, Mohommad;Joshi, Shambhu Prasad
    • Journal of Forest and Environmental Science
    • /
    • v.34 no.2
    • /
    • pp.145-152
    • /
    • 2018
  • Quantification of Carbon stock has become in the contest of changing climate and mitigation potential of forests. Two different forest types, Dry Shiwalik Sal Forest and Moist Shiwalik Sal Forest in Barkot and Lachchiwala of Doon Valley, Western Himalaya are selected for the study. Volume equations, destructive sampling and laboratory analysis are done to estimate the carbon stock in different carbon pools like trees, shrubs, herbs and soils. Considerable variations are observed in terms of carbon stocks in different forest types. In Dry Shiwalik Sal Forest, carbon stock density varied between 129.81 and $136.00MgCha^{-1}$ while in Moist Shiwalik Sal Forest, carbon stock density ranged from 222.29 to $271.67MgCha^{-1}$. Tree species like Shorea robusta, Syzigium cumini, Miliusa velutina, Acacia catechu, and Mallotus philippensis had significant role in carbon sequestration. Shorea robusta had contributed highest in carbon stock due to highest density. Total of 2,338,280.165 Mg carbon stock was estimated in all the forest types.

Electrical Properties of Carbon Black-PVC and Carbon Black-HDPE Composites (Carbon Black-PVC와 Carbon Black-HDPE 복합재료의 전기적 성질)

  • Jeong, Sang-Gi;No, Si-Tae;Im, Seung-Sun
    • Textile Science and Engineering
    • /
    • v.28 no.12
    • /
    • pp.82-92
    • /
    • 1991
  • Electrical conductive PVC and HDPE composites were prepared by melt compounding method with electrical conductive carbon black. The electrical and mechanical properties of carbon black composites were affected by the particle size, surface area, density, aggregation morphology and dispersion state of carbon black, According to the carbon black contents, the composites have shown the behaviors of insulator, semiconductor and conductor. The percolation threshold of the carbon black composite was examined. From the temperature dependence of conductivity for the composites, we found that Carbon Black-PVC composites were very stable and reproducible to the temperature changes. Carbon Slack-HDPE composites have shown a PTC(positive temperature coefficient of resistively) effect which has a sudden resistively increase by thermal expansion of polymer at melting region. To prevent a NTC(negative temperature coefficient of resistively) effect and improve reproducibility of conductivity, the chemical crosslinking was accomplished.

  • PDF