• Title/Summary/Keyword: carbon-reduction

Search Result 2,318, Processing Time 0.042 seconds

Effect of Attitudinal Factors on Stated Preference of Low-carbon Transportation Services (개인성향 요인이 탄소저감형 교통서비스 잠재선호에 미치는 영향에 관한 연구)

  • Yoonhee Lee;Gyeongjae Lee;Sangho Choo
    • The Journal of The Korea Institute of Intelligent Transport Systems
    • /
    • v.22 no.6
    • /
    • pp.49-65
    • /
    • 2023
  • In response to the growing global concern for the environment, the international community has recently committed to achieving 'carbon neutrality.' As a result, numerous studies have been conducted on mode choice models that include carbon emissions as a variable. However, few studies have established a correlation between individual preferences and carbon emissions. In this study, a new mode of transportation named sustainable public transit (SPT), incorporating carbon-reducing transport options like electric scooters, is proposed. Analyzing the individual preferences of commuters on carbon emissions through factor analysis, a stated preference (SP) survey was conducted. A mode choice model for SPT was constructed using multinomial logit models. The results of the analysis showed that gender, income, and specific preferences, such as a passion for exploring new routes, a preference for intermodal transfers, knowledge of carbon reduction, and carbon reduction practices, significantly influence latent preferences for SPT. Therefore, this study is significant as it considers carbon emissions as an attribute variable during the construction of mode choice models and reflects the individual preference variables associated with carbon reduction.

The Electrocatalytic Reduction of Oxygen by Bis-Cobalt Phenylporphyrins in Various pH Solutions (여러 가지 pH 수용액에서 Bis-Cobalt Phenylporphyrin 유도체들에 의한 산소의 전극 촉매적 환원)

  • Yong-Kook Choi;Ki-Hyung Chjo;Jong-Ki Park
    • Journal of the Korean Chemical Society
    • /
    • v.37 no.8
    • /
    • pp.735-743
    • /
    • 1993
  • The electrocatalytic reduction of oxygen is investigated by cyclic voltammetry and chronoamperometry at glassy carbon electrode and carbon microelectrode coated with a variety of cobalt phenylprophyrins in various pH solutions. Oxygen reduction catalyzed by the monomeric porphyrin Co(Ⅱ)-TPP mainly occurs through the 2e$^-$ reduction pathway resulting in the formation of hydrogen peroxide whereas electrocatalytic process carried out 4e$^-$ reduction pathway of oxygen to H$_2$O at the electrodes coated with cofacial bis-cobalt phenylporphyrins in acidic solution. The electrocatalytic reduction of oxygen is irreversible and diffusion controlled. The reduction potentials of oxygen in various pH solutions have a straight line from pH 4 to pH 13, but level off in strong acidic solution. The reduction potentials of oxygen shift to positive potential more 400 mV at the electrode coated with monomer Co-TPP compound than bare glassy carbon electrode while 750 mV at the electrode coated with dimer Co-TPP compound.

  • PDF

Drag Reduction Induced by Increased Kinematic Viscosity of Nanofluids Containing Carbon Nanotubes in A Horizontal Tube (카본나노튜브 나노유체의 동점성계수 증가로 인한 관내 유동에서의 항력 감소)

  • Yu, Jiwon;Jung, Se Kwon;Choi, Mansoo
    • Particle and aerosol research
    • /
    • v.9 no.4
    • /
    • pp.271-277
    • /
    • 2013
  • This article reports the drag reduction phenomenon of aqueous suspensions containing carbon nanotubes (CNTs) flowing through horizontal tubes. Stable nanofluids were prepared by using a surfactant. It is found that the drag forces of CNT nanofluids were reduced at specific flow conditions compared to the base fluid. It is found that the friction factor of CNT nanofluids was reduced up to approximately 30 % by using CNT nanofluids. Increased kinematic viscosities of CNT nanofluids are suggested to the key factors that cause the drag reduction phenomenon. In addition, transition from laminar to turbulent flow is observed to be delayed when CNT nanofluids flow in a horizontal tube, meaning that drag reduction occurs at higher flow rates, that is, at higher Reynolds numbers.

Electrochemical Reduction of High Pressure Carbon Dioxide on Metal Electrodes and Gas Diffusion Electrodes

  • Hara, Kohjiro;Sakata, Tadayoshi
    • Analytical Science and Technology
    • /
    • v.8 no.4
    • /
    • pp.683-689
    • /
    • 1995
  • Electrochemical reduction of carbon dioxide under high pressure on Fe electrodes and a gas diffusion electrode containing Pt catalyst (Pt-GDE) had been investigated. Formic acid was formed on Fe electrode with a faradaic efficiency of 60% at a current density of $120mA\;cm^{-2}$ under 30 atm of $CO_2$. Hydrocarbons such as $CH_4$, $C_2H_6$, $C_3H_6$, $1-C_4H_8$, and $n-C_5H_{12}$ are also formed. The distribution of hydrocarbons followed well the Schultz-Flory distribution. $CH_4$ was formed efficiently as the main reduction product on Pt-GDE.

  • PDF

Technique Status of Carbon Fibers-reinforced Composites for Aircrafts (항공기용 탄소섬유강화 복합재료의 기술동향)

  • Kim, Ki-Seok;Park, Soo-Jin
    • Elastomers and Composites
    • /
    • v.46 no.2
    • /
    • pp.118-124
    • /
    • 2011
  • Recently, the need of new materials which have excellent physical properties and functional characteristics has been increased in all industries. In particular, body weight reduction via new materials in aerospace industry was significantly emphasized by the requirement of environmental protection through the fuel savings and reduction of greenhouse gas, i.e., carbon dioxide($CO_2$). Also, for various applications, the development of high performance custom materials with excellent physical properties was the current primary goal of materials science and technology. In this respect, carbon fiber-reinforced composites were the most candidates among the various materials. Indeed, carbon fiber-reinforced composites have been lately used as essential materials for the weight reduction of aircraft and the demand has increased remarkably. Therefore, in this paper, we focused on the need of carbon fiber composites in the fields of aircraft and technique status.

Recovery of Lithium and Leaching Behavior of NCM Powder by Carbon Reductive Treatment from Li(NCM)O2 System Secondary Battery Scraps (Li(NCM)O2계(係) 이차전지(二次電池) 공정(工程)스크랩의 탄소환원처리(炭素還元處理)에 의한 리튬회수(回收) 및 NCM 분말(粉末)의 침출거동(浸出擧動))

  • Kim, Dae Weon;Jang, Seong Tae
    • Resources Recycling
    • /
    • v.22 no.4
    • /
    • pp.62-69
    • /
    • 2013
  • A study on the recovery of lithium and leaching behavior of NCM powder by carbon reduction for NCM-system Li-ion battery scraps was conducted. First of all, the oxide powders of NCM-system with layer structure were decomposed by carbon, lithium was converted to lithium carbonate by carbon reaction at above $600^{\circ}C$. The lithium carbonate powders with 99% purity were manufactured by washing method with water and concentration process for NCM powder after carbon reduction. The reaction yield was approximately 88% at $800^{\circ}C$ by carbon reduction. At this time, leaching efficiency at 2M sulfuric acid concentration was over 99% for cobalt, nickel and manganese.

Mesoporous Carbon as a Metal-Free Catalyst for the Reduction of Nitroaromatics with Hydrazine Hydrate

  • Wang, Hui-Chun;Li, Bao-Lin;Zheng, Yan-Jun;Wang, Wen-Ying
    • Bulletin of the Korean Chemical Society
    • /
    • v.33 no.9
    • /
    • pp.2961-2965
    • /
    • 2012
  • Mesoporous carbons with tailored pore size were prepared by using sucrose as the carbon source and silicas as the templates. The silica templates were obtained from a hydroxypropyl-${\beta}$-cyclodextrin-silica hybrids using ammonium perchlorate oxidation at different temperatures to remove the organic matter. The structures and surface chemistry properties of these carbon materials were characterized by $N_2$ adsorption, TEM, SEM and FTIR measurements. The catalytic performances of these carbon materials were investigated through the reduction of nitroaromatic using hydrazine hydrate as the reducing agent. Compared with other carbon materials, such as active carbon, and carbon materials from the silica templates obtained by using calcination to remove the organic matter, these carbon materials exhibited much higher catalytic activity, no obvious deactivation was observed after recycling the catalyst four times. Higher surface area and pore volume, and the presence of abundant surface oxygen-containing functional groups, which originate from the special preparation process of carbon material, are likely responsible for the high catalytic property of these mesoporous carbon materials.

Electrochemical Reduction of Carbon Dioxide Using a Proton Exchange Membrane (양이온 교환막을 이용한 이산화탄소의 전기화학적 환원)

  • Kim, Hak-Yoon;Ahn, Sang Hyun;Hwang, Seung Jun;Yoo, Sung Jong;Han, Jonghee;Kim, Jihyun;Kim, Soo-Kil;Jang, Jong Hyun
    • Journal of the Korean Electrochemical Society
    • /
    • v.15 no.4
    • /
    • pp.216-221
    • /
    • 2012
  • Electrochemical reduction of carbon dioxide has been widely studied by many scientists and researchers. Recently, the production of formic acid, which is expensive but highly useful liquid material, is receiving a great attention. However, difficulties in the electrochemical reduction process and analyzing methods impede the researches. Therefore, it is important to design an adequate system, develop the reduction process and establish the analyzing methods for carbon dioxide reduction to formic acid. In this study, the production of formic acid through electrochemical reduction of carbon dioxide was performed and concentration of the product has been analyzed. Large scale batch cell with proton exchange membrane was used in the experiment. The electrochemical experiment has been performed using a series of metal catalysts. Linear sweep voltammetry (LSV) and chronoamperometry were performed for carbon dioxide reduction and electrochemical analysis using silver chloride and platinum electrode as a reference electrode and counter electrode, respectively. The concentration of formic acid generated from the reduction was monitored using high performance liquid chromatography (HPLC). The results validate the appropriateness and effectiveness of the designed system and analyzing tool.

Selective Reduction of $\alpha,\beta$-Unsaturated Ketones with Borohydride Exchange Resin-$CuSO_4$ in Methanol

  • Yoon, Nung-Min;Sim, Tae-Bo
    • Bulletin of the Korean Chemical Society
    • /
    • v.14 no.6
    • /
    • pp.749-752
    • /
    • 1993
  • Borohydride exchange resin $(BER)-CuSO_4$ system readily reduces {\alpha},{\beta}$-unsaturated ketones to the corresponding saturated alcohols quantitatively. This reduction tolerates many functional groups such as carbon-carbon multiple bonds, chlorides, epoxides, esters, amides and nitriles.

Carbon Reduction Investments under Direct Shipment Strategy

  • Min, Daiki
    • Management Science and Financial Engineering
    • /
    • v.21 no.1
    • /
    • pp.25-29
    • /
    • 2015
  • Recently much research efforts have focused on how to manage carbon emissions in logistics operations. This paper formulates a model to determine an optimal shipment size with aims to minimize the total cost consisting not only of inventory and transportation costs but also cost for carbon emissions. Unlike the literature assuming carbon emission factors as a given condition, we consider the emission factors as decision variables. It is allowed to make an investment in improving carbon emission factors. The optimal investment decision is shown to be of a threshold type with respect to unit investment costs. Moreover, the findings in this work provide insights on the various elements of the investment decision and their impacts.