• Title/Summary/Keyword: 아산화질소

Search Result 167, Processing Time 0.025 seconds

Estimation of Greenhouse Gas Emission from Solid Waste Incinerators (폐기물 소각시설에서 발생하는 온실가스 배출량 조사)

  • Jang, Young-Gi;Choi, Sang-Jin;Kim, Gwan;Jeon, Eui-Chan;Kim, Deuk-Su
    • Proceedings of the Korea Air Pollution Research Association Conference
    • /
    • 1999.10a
    • /
    • pp.274-276
    • /
    • 1999
  • 지구 기온상승에 영향을 주는 가스는 여러 부문에서 배출되지만, 환경기초시설에서는 소각시설에서 이산화탄소($CO_2$)와 아산화질소($N_2$O), 쓰레기매립지에서 메탄(CH$_4$), 하폐수처리장에서 메탄(CH$_4$)과 아산화질소($N_2$O)가 주로 배출된다. 그러나 우리나라에서는 이 부문의 배출량에 대하여 아직 체계적인 조사가 이루어지지 못하였다. 본 연구의 목적은 우리나라의 폐기물 소각시설에서 발생하는 온실가스 배출량을 산출하는 것이다.(중략)

  • PDF

MANAGEMENT OF ADULT DENTAL PHOBIC PATIENTS (성인 치과공포증 환자의 치료)

  • Kim, Dae-Eop
    • Journal of the korean academy of Pediatric Dentistry
    • /
    • v.34 no.2
    • /
    • pp.341-348
    • /
    • 2007
  • We dentists perform many of routine dental procedures and must deal with much of the population's dental anxiety and fear. Dentists have used many non-pharmacological modalities initially to overcome anxiety and fear, including distraction, empathy, desensitization, and so on. However, certain patients need pharmacological backup of anxiety and fear to conquer dental treatment. This article presents four cases to introduce the methods from nitrous oxide and oxygen inhalation to general anesthesia for difficult adult dental phobic patients to deal with.

  • PDF

Emissions of Nitrous oxide from Wastewater Treatment Process by Floating Flux Chamber (Floating Flux Chmber에 의한 하.폐수처리시설에서의 아산화질소 발생특성)

  • 전의찬;장영기;최경식;김전희;서경애;박종호;이성호
    • Proceedings of the Korea Air Pollution Research Association Conference
    • /
    • 2002.11a
    • /
    • pp.440-441
    • /
    • 2002
  • 지구온난화를 유발하는 온실가스의 대표적인 성분으로는 이산화탄소, 메탄, 아산화질소, CFC 등을 들 수 있으며, 주요 온실기체들에 대한 대기 중 농도가 과거보다 현저하게 증가되었음이 확인되고 있다. $N_2$O은 대기 중의 농도는 낮으나 상대적으로 지구온난화에 기여하는 정도가 $CO_2$에 비해 질량기준으로 310배가 높고, 생체 발생량이 크기 때문에 지구규모수지에 있어서 신중하게 고려되어야 한다. 온실기체의 국가배출자료는 기후변화협약과 관련된 국제협상 및 국내 저감대책 수립에 없어서는 안될 중요한 기초자료이다. (중략)

  • PDF

Investigation on emission characteristics of nitrous oxide from marine diesel engine (선박용 디젤엔진에서 아산화질소의 배출특성에 대한 연구)

  • Yoo, Dong-Hoon
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.38 no.9
    • /
    • pp.1051-1056
    • /
    • 2014
  • Nitrous oxide ($N_2O$) is naturally generated from biological activity, such as bacteria's material exchange. However, recent $N_2O$ concentration in the atmosphere has being increased by the human activities such as industrial growth. One of factors to increase $N_2O$ concentration in the atmosphere is a $N_2O$ emission caused by the combustion of marine fuel oils. The marine transportation presently handles over 99 percent of the international freight cargoes and the number of ship is continuously increasing with increment of cargoes. In this study, author conducted a series of the experimental investigations on which combustion of fuels containing different element concentrations used in a 4-stroke marine diesel engine affect $N_2O$ emissions in the exhaust gas. Moreover, it is assessed on the extent to which fuel combustion patterns in the combustion chamber affect $N_2O$ emissions.

The Partial Oxidation of Methane by Nitrous Oxide over Silica-Supported 12-Molybdophosphoric Acid (실리카 담지 12-몰리브도인산 촉매상에서의 아산화질소에 의한 메탄의 부분산화반응)

  • Hong, Seong-Soo;Woo, Hee-Chul;Ju, Chang-Sik;Lee, Gun-Dae;Moffat, J.B.
    • Applied Chemistry for Engineering
    • /
    • v.5 no.1
    • /
    • pp.139-148
    • /
    • 1994
  • The partial oxidation of methane with nitrous oxide on silica-supported metal-oxygen cluster compounds, known as heteropoly acids, has been studied. The effects of several variables such as reaction temperature, partial pressure of reactants, residence time, loading of the catalysts, and pretreatment temperature, on the conversion and product distribution were observed. The kinetics also has been studied. The conversion and yield of formaledehyde show maximum values at a loading of 20 wt%. The apparent reaction order of methane conversion is ca. 1.0 with respect to $CH_4$ and ca. 0.4 with respect to $N_2O$. In addition, the apparent activation energy is 30.78 kcal/mole. The addition of small quantities methane whereas water introduced to the reactant decreased the activity of catalyst under present study.

  • PDF

Visualization of Transient Ignition Flow-field in a 50 N Scale N2O/C2H5OH Thruster (50 N급 아산화질소/에탄올 추력기의 점화 과도 유동장 가시화)

  • Kim, Dohun;Park, Jaehyeon;Yu, Myunggon;Lee, Kyungeun;Koo, Jaye
    • Journal of the Korean Society of Propulsion Engineers
    • /
    • v.18 no.6
    • /
    • pp.11-18
    • /
    • 2014
  • The combustion flowfield at the near-injector region of a 50 N scale $N_2O/C_2H_5OH$ thruster was visualized using shadowgraph technique. The explosive ignition was occurred at the design spray condition, and the expanding combustion gas quenched the flame immediately. Approximately after 83 ms from the initial ignition, the propellant spray was re-ignited, and the flame was stabilized after 23 ms elapsed. In the increased oxidizer flow rate condition, the transient pressure at the moment of ignition was smoother than explosive ignition, and the blow down phenomenon was not appeared in the same operating sequence. In addition, the flame was stabilized within 17 ms, and it is caused by improved propellants mixing before ignition.

Combustion Performance of a Coaxial Porous Injector using Ethanol/N2O Propellant (동축형 다공성재 분사기의 에탄올/아산화질소 연소성능)

  • Kim, Dohun;Lee, Keonwoong;Koo, Jaye
    • Journal of the Korean Society of Propulsion Engineers
    • /
    • v.17 no.5
    • /
    • pp.37-46
    • /
    • 2013
  • The gas jet from a coaxial porous injector for two-phase flows is discharged radially from the porous surface, which encloses the center liquid jet. Several hot-firing test using ethanol/nitrous oxide propellants was conducted to analyze the effect of oxidizer/fuel ratio on the combustion performance, and the uncertainty analysis was performed for the results. The characteristic velocity was affected by oxidizer/fuel ratio similarly with the results of CEA calculation except that the maximum characteristic velocity was appeared in the stoichiometric ratio. The characteristic velocity efficiency was increased as the oxidizer/fuel ratio increases.

Characteristics of Intravenous Midazolam Sedation with Nitrous Oxide in Pediatric Dental Treatment (소아환자에서 midazolam 정주 및 아산화질소 흡입진정법 하 치과치료의 특성)

  • Kim, Hyuntae;Song, Ji-Soo;Hyun, Hong-Keun;Kim, Young-Jae;Kim, Jung-Wook;Jang, Ki-Taeg;Lee, Sang-Hoon;Shin, Teo Jeon
    • Journal of the korean academy of Pediatric Dentistry
    • /
    • v.47 no.1
    • /
    • pp.53-61
    • /
    • 2020
  • Midazolam is a short-acting benzodiazepine that is widely used in pediatric dental sedation. However, its clinical effectiveness as an intravenous sedative agent in children has not been widely documented. A retrospective study was conducted to evaluate the efficacy and safety of intravenous midazolam and nitrous oxide inhalation sedation in pediatric dental treatment. The subjects were 115 patients (118 cases) who received dental treatment under intravenous midazolam and nitrous oxide inhalation sedation. Demographic factors, general health status, sedation time, midazolam and nitrous oxide dosage, and success rate of sedation were evaluated from electronic medical records. Behavioral management was the main reason of choosing sedation. Mean duration of sedation was 56.7 minutes for surgical treatment, and 74.4 minutes for restorative treatment. The initial dosage of intravenous midazolam was 0.051 ± 0.019 mg/kg. In 34 cases (28.8%), additional midazolam of 0.036 ± 0.057 mg/kg was delivered during the treatment. The concentration of nitrous oxide was maintained between 40% and 50%. The success rate of sedation was 99% (n = 117). In 1 case, laryngospasm occurred and the patient was reversed with benzodiazepine antagonist, flumazenil. Intravenous midazolam sedation with nitrous oxide was shown to be clinically effective for the dental treatment in children, if administered by trained personnel and patients are carefully selected in accordance with guidelines.