• Title, Summary, Keyword: Emission

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INFLUENCE OF OPERATION PATTERNS OF LIGHT-DUTY FREIGHT VEHICLES ON NOx POLLUTION AT LOCAL ROADSIDES

  • Saito, A.;Ueki, S.;Takada, Y.
    • International Journal of Automotive Technology
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    • v.7 no.3
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    • pp.269-276
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    • 2006
  • Running tests on roads were conducted to clarify the influences of road infrastructure, traffic condition and vehicle's emission level to the amount of emission at local roadsides, and to reveal the operation patterns which can reduce the emission peaks. NOx emission peaks of two light duty freight diesel vehicles which have different emission levels were evaluated by using an on-board measurement system. Tests were carried out with various payload conditions and road conditions. As a result many NOx emission peaks were observed when the vehicles were starting or accelerating at intersections. The test vehicle which has higher emission level caused higher frequency and level of NOx emission peaks. Shifting up at lower engine speed in combination with lower acceleration brought out not only reduction of NOx emission peaks level but also of $CO_2$ mass emission.

Semiconductor Nanowires;Their Emission Stability and Energy Distribution

  • Yu, Se-Gi;Yi, Whi-Kun;Lee, Sang-Hyun;Heo, Jung-Na;Jeong, Tae-Won;Lee, Jeong-Hee;Lee, Soo-Chang;Kim, J.M.;Lee, Cheol-Jin;Lyu, Seung-Chul;Han, Jae-Hee;Yoo, Ji-Beom
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.1028-1031
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    • 2002
  • Ga-based semiconductor nanowires (GaN, GaP) were synthesized by the reaction of Ga metal and GaN/GaP powder with a $NH_3/Ar$ gas using thermal chemical vapor deposition. The field emission and emission stability under oxygen and argon environments were investigated. Field emission energy distributions of electrons from these nanowires revealed that field emission mechanism of the semiconductor nanowires were different from carbon nanotubes.

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Numerical Calculation Study on the Generalized Electron Emission Phenomenon

  • Kim, Hee-Tae;Yu, Soon-Jae
    • Journal of Information Display
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    • v.10 no.4
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    • pp.158-163
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    • 2009
  • There are two kinds of well-known electron emissions from metal: field and thermionic emission. For thermionic emission, electrons come out of a metal due to the thermal energy, whereas for field emission, electrons tunnel out of a metal through the strong electric field. In this study, the most general electron emission caused by the temperature and electric field with a free electron gas model was considered. The total current density of electron emission comes from the field emission effect, where the electron energy is lower than vacuum, and from the thermionic-emission effect, where the electron energy is higher than vacuum. The total current density of electron emission is shown as a function of the temperature for a constant electric field, and as a function of the electric field for a constant temperature.

Pulse electric field-excited electron emission from Pb$(Zr_xTi_{1-x})O_3$ ceramics prepared by conventional solid state reaction (고상 반응법에 의해 제조된 Pb$(Zr_xTi_{1-x})O_3$ 세라믹스에서 펄스 전계에 의한 전자 방출)

  • Kwak, Sang-Hee;Kim, Tae-Heui;Park, Kyung-Bong;Kim, Chang-Soo
    • Proceedings of the KIEE Conference
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    • pp.1867-1869
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    • 1999
  • Pulse electric field induced electron emission from ferroelectrics has been studied with Pb$(Zr_xTi_{1-x})O_3$ ceramics with varying Zr/Ti ratio from 35/65 to 65/35, Electron emission was proved to be concentrated on the electrode edge by emission profile test and emission capture photographs. The 65/35 composition showed largest emission charge in lowest field and lowest emission threshold field. The emission characteristics are closely dependent on their ferroelectric properties in hysteresis curve. Electron emission charge increases with the polarization charge and emission threshold voltage is dependent on coercive field regardless of their composition. But dielectric constant has little relation with emission property. Electron emission charge increases exponentially with pulse electric field irrespective of composition. On the assumption that the surface potential is linear with the pulse electric field, electron emission can be regarded as a field emission at the electrode edge using Fowler-Nordheim plot of ln$(Q_e/E_{fe})$ to $1/E_{fe}$.

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A Study on the Calculation Model for Tier 3 Greenhouse Gas(GHG) Emission Factors of Diesel Locomotives (디젤기관차 Tier 3 온실가스 배출계수 산정 모델 연구)

  • Rhee, Young-Ho;Kim, Yong-Ki;Lee, Jae-Young;Jung, Woo-Sung
    • Proceedings of the KSR Conference
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    • pp.1315-1319
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    • 2011
  • As government's policy is enacted to reduce greenhouse gas emission in transportation sector, railroad sector has to estimate amount of emission and propose feasible methods to reduce emission. To calculate accurate emission of railroad sector, we performed a study on the calculation model development for Tier 3 GHG emission factors. According to IPCC guide line, Tier 3 emission factor reflects individual characteristic of diesel locomotive. For this reason, we estimated GHG emission factor by stratified diesel locomotive and the result show difference of emission factor by notch changing. Therefore, the analysis of notch frequency during operation is required to develop Tier 3 emission factor, and we analysed a running pattern of diesel locomotive. As a result, idle and 8 notch consist about 70% of total running distance. In conclusion, the calculation model suppose that Tier 3 GHG emission factor is the sum of multiplied emission factor by weights in each notch. This result can contribute to Tier 3 emission factor calculation and reduction method development of emission in railroad sector by managing driving efficiency and technology development.

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Electron Emission from $Pb(Zr_xTi_{1-x})O_3$ Ferroelectrics by Pulsed Electric Field (펄스 전기장에 의한 $Pb(Zr_xTi_{1-x})O_3$ 강유전체의 전자 방출)

  • 김용태;윤기현;김태희;박경봉;곽상희
    • Journal of the Korean Ceramic Society
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    • v.37 no.1
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    • pp.6-11
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    • 2000
  • Electron emission from the Pb(ZrxTi1-x)O3 ferroelectrics by pulsed electric field has been investigated as a function of Zr/Ti ratios such as 35/65, 50/50 and 65/35 below 250kV/cm. Electrons were emitted regardless of the applied field polarity to the rear electrode. When the negative field was applied to the rear electrode, the electron emission charge was more stable. It was proved that the electrons were emitted at the edge of the upper electrode. The emission charge increased in order of 65/35>50/50>35/65. The electron emission characteristics were dependent on the ferroelectric properties such as polarization and coercive field. The emission charge and emission threshold field were affected by the polarization change and the coercive field, respectively. This result explains that the electron emission is a field emission with polarization induced surface potential by a modified Fowler-Nordheim plot of emission charge.

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Estimation of Exhaust NOx Emission for Marine Engines (선박엔진의 NOx 배출량 산정)

  • 김대식;엄명도
    • Journal of the Korean Society of Marine Engineering
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    • v.24 no.4
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    • pp.441-445
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    • 2000
  • Considering international status of our country as world class ship builder and geographical characteristics encircled by sea in three facets, controlling of air pollutants emission from marine engines becomes more and more important issue in recent days. Implementation of immediate pollutants emission control regulation and standardization of test and certification procedure are required to reduce air pollution from marine engines. But cost increments due to additional equipment of emission control device and development and certification test expenses as well as depreciation of fuel economy should be considered. To satisfy those air pollution reduction and economic requirements, we should make our own interpretation of IMO standard and implementation schedule depending on our country's status. For this purpose we measured NOx emission from small and middle class marine engines to calculate emission factor and total pollutant emission in our country. With the comparison and analysis of other countries emission control regulation we proposed basic data of total emission from marine engine and future emission control standard in our country. According to our estimation, 62% of total NOx emission of marine engines comes from fishing boat and 38% from commercial vessels. The portion of NOx emission from marine engine is 18.6% of whole country NOx emission. Due to the voyage characteristics of middle and large vessel and necessity of international harmonization of marine engine pollutants emission control standard, it is inevitable to adopt IMO standard for middle and large marine engines. But considering technological and cost effect of fishing boat operating in near sea, it is resonable to set a standard within 80% of measured value at the moment and gradually implement the same IMO standard in near future.

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A Study on Carbon Emission Credit Acquisition in Domestic Railroad Sector (국내 철도분야 탄소배출권 확보방안 연구)

  • Choi, Yo-Han;Lee, Cheul-Kyu;Kim, Yong-Ki
    • Proceedings of the KSR Conference
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    • pp.2949-2951
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    • 2011
  • It is expected that domestic railway vehicle operation companies may be subjected to GHG emission reduction when GHG emission system is enforced. This study aimed that reviewing on GHG emission system such as CDM, VCS and KCER, and analysing availability of GHG emission credit acquisition for railroad transportation sector. In order to estimate GHG emission credit, a GHG emission estimation methodology should be developed, which includes GHG emission baseline estimation and GHG emission monitoring method, MRV method and etc. Modal shift project, high speed train technology, straight lining project, mass transportation technology, operation optimization tehcnology and etc. may produce GHG emission credit.

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A Basic Study on the Development of GHG Emission Factor from Diesel-Powered Railcars in Korea (국내 디젤철도차량의 온실가스 배출계수 개발방향 연구)

  • Lee, Jae-Young;Kim, Yong-Ki;Lee, Cheul-Gyu;Rhee, Young-Ho;Lee, Cheol
    • Proceedings of the KSR Conference
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    • pp.2258-2261
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    • 2010
  • Since national mid-term target for GHG reduction was determined in 2009, various efforts in transportations have been prepared. Generally, the GHG emission of transportation is calculated using the emission factor published from IPCC guideline(2006). However, it is necessary to develop new emission factors considering the properties of transportation as well as fuel. In Korean railroad, main emission sources are the consumption of diesel and electricity from railcar operation. The GHG emission of electric-powered railcars can be estimated using national electric emission factor, but diesel-powered railcars show different trends. The purpose of this study was to establish the development plans of emission factors for diesel-powered railcars. As a result, the emission factors of diesel-powered railcars were classified into railcar type, engine type and life cycle, notch, load, and traffic volume. In future, several emission factors with this category will be presented quantitatively through field tests with the order of priority.

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Regional Supply Strategies for Renewable Energy Sources based on Contribution Level of GHG Emission Reduction (신재생에너지의 온실가스감축 기여도에 따른 지역별 보급전략)

  • Kim, Hyun Seok
    • Current Research on Agriculture and Life Sciences
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    • v.32 no.4
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    • pp.215-223
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    • 2014
  • This study examines the contribution level of greenhouse gas(GHG) emission reduction and installation costs of renewable energy facilities. The GHG emission forecasts and industrial structures in the 16 regions of Korea are then analyzed to identify the proper supply of renewable energy sources for each region. The results show that water power is the most effective and efficient renewable energy source to reduce GHG emissions, followed by sunlight, wind power, geothermal heat, and solar heat, respectively. The 16 regions are then categorized into 4 groups based on their GHG emission forecast and industrial structure: high emission and manufacturing group, low emission and manufacturing group, low emission and service group, and high emission and service group. The proper supply of renewable energy sources for each group is then determined based on the contribution level and cost efficiency of GHG emission reduction.