• Title/Summary/Keyword: oxidation speed

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Effect of Applied Load and Sliding Speed on Wear Behavior of Thermally Sprayed STS316 Coating (STS316 용사코팅의 마모거동에 미치는 작용하중 및 미끄럼속도의 영향)

  • Lee, Jae-Hong;Kim, Yeong-Sik
    • Journal of Power System Engineering
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    • v.18 no.5
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    • pp.74-79
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    • 2014
  • This article aims at investigating the effect of applied load and sliding speed on wear behavior of thermally spraryed STS316 coating. STS316 coatings were fabricated by flame spray process according to optimal parameters on steel substrates. Dry sliding wear tests were performed on STS316 coating using four different applied load as 10, 15, 20 and 25 N and four different sliding speed as 15, 30, 45 and 60 rpm. Wear behavior on worn surface was investigated using scanning electron microscope(SEM) and energy disperive X-ray spectroscopy(EDS). The dominant wear mechanism of STS316 coating under low applied load and sliding speed was oxidation on worn surface. However, under high applied load and sliding speed the principal wear mechanism was abrasion on oxidation film and damage of oxidation film.

Removal of Bisphenol-A using Rotating Photocatalytic Oxidation Drum Reactor (RPODR)

  • Son, Hee-Jong;Jung, Chul-Woo;Kim, Seung-Hyun
    • Environmental Engineering Research
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    • v.13 no.4
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    • pp.197-202
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    • 2008
  • This study evaluated the photocatalytic oxidation of BPA using the RPOD reactor under various conditions. This study found that the RPOD was effective for BPA degradation. It could reduce 1 mg/L of BPA by half within 5 min under the optimum conditions. According to the study results, $TiO_2$ coating was important for the BPA oxidation. As the coating thickness increased, the removal efficiency improved. The light source, the light intensity and the drum rotating speed were important for the oxidation. The UV light was more effective for the BPA degradation than the visible light. The removal efficiency improved with increasing intensity. As the drum speed increased, the removal efficiency improved. The maximum speed was 240 rpm in this study. Addition of air and nitrogen was not beneficial for the BPA degradation in this study probably due to enough oxygen in the water.

OXIDATION CHARACTERISTICS OF PARTICULATE MATTER ON DIESEL WARM-UP CATALYTIC CONVERTER

  • Choi, B.C.;Yoon, Y.B.;Kang, H.Y.;Lim, M.T.
    • International Journal of Automotive Technology
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    • v.7 no.5
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    • pp.527-534
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    • 2006
  • Modern passenger cars with diesel engines are equipped with DOC(diesel oxidation catalyst) for the purpose of reducing HC and CO in the exhaust stream. Cold start exhaust emissions pose troubles here as on gasoline engine vehicles. As a result, some of the diesel passenger cars roll off todays the assembly lines with WCC(warm-up catalytic converter). Oxidation characteristics of the particulates in WCC is analyzed in this study by EEPS(engine exhaust particulate size spectrometer). The maximum number of PM is found to come out of WCC in sizes near 10nm when an HSDI diesel engine is operated under the conditions of high speed and medium to heavy load. When the temperature of the WCC exceeds $300^{\circ}C$, the number of PM smaller than 30 nm in diameter sharply increases upon passing through the WCC. Total mass of emitted PM gets reduced downstream of the WCC under low speed and light load conditions due to adsorption of PM onto the catalyst. Under conditions of high speed and medium to heavy load, the relatively large PM shrink or break into fine particles during oxidation process within the WCC, which results in more mass fraction of fine particles downstream of the WCC.

Formic Acid Oxidation Depending on Rotating Speed of Smooth Pt Disk Electrode

  • Shin, Dongwan;Kim, Young-Rae;Choi, Mihwa;Rhee, Choong Kyun
    • Journal of Electrochemical Science and Technology
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    • v.5 no.3
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    • pp.82-86
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    • 2014
  • This work presents the variation of formic acid oxidation on Pt depending on hydrodynamic condition using a rotating disk electrode. As the rotating speed increases, the oxidation rate of formic acid decreases under voltammetric and chronoamperometric measurements. The coverages of poison formed from formic acid during the chronoamperomertric investigations decrease when the rotating speed increases. As the roughness factor of Pt electrode surface increases, on the other hand, the current density of formic acid oxidation increases. These observations are discussed in terms of the tangential flow along Pt electrode surfaces generated by the rotating disk electrode, which reduces a contact time between formic acid and a Pt site, thus the formic acid adsorption.

Laser hardening and Wear Characteristics of Surfaces hardening steel by YAG LASER (′YAG 레이저에 의한 표면경화강의 레이저 경화와 마멸특성)

  • 옥철호;서영백;조연상;배효준;박흥식;전태옥
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1999.11a
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    • pp.63-70
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    • 1999
  • Surface hardening of plain carbon steel (SM45C) by Laser are usually much finer and stronger than those of the base metals. The present study was under taken to investigate the wear resistance and a processing parameters such as, power density, pulse width, defocusing distance, and molten depth for surface modification of plain carbon steel. The wear test was carried out under experimental condition using the wear test device, and in which the annular surfaces of wear test specimens as well as mating specimen of alumina ceramics($Al_2O_3$) was rubbed in dry sliding condition. It is shown that molten depth and width depend on defocusing distance. The wear loss on variation of sliding speed was much in lower speed range below 0.2m/sec and in higher speed range above 0.7m/sec, but wear loss was little in intermediate speed range. It depends on oxidation speed and wear speed.

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Humidity dependent size control of local anodic oxidation on graphene using Atomic Force Microscope (원자힘 현미경의 습도 조절에 의한 그래핀 국소 산화)

  • Ko, Seoknam;Lee, Seong jun;Son, Maengho;Ahn, Doyeol;Lee, Seung-Woong
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2014.11a
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    • pp.226-227
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    • 2014
  • We demonstrate nanoscale local anodic oxidation (LAO) patterning on few layer graphene using atomic force microscope (AFM) at room temperature and normal atmosphere. We focus on the humidity dependency in nanoscale oxidation of graphene. The relationship between the oxidation size and the AFM setting values, such as set point, tip speed, and humidity are observed. By changing these values, proper parameters were found to produce features on demand size. This technique provides an easy way to form graphene oxide lithography without any chemical resists. We have obtained oxidation size down to 50-nm with 6-nm-height oxide barrier line with $0.1{\mu}m/s$ tip scanning speed and micrometer size symbols on a graphene flake. We attribute the bumps to local anodic oxidation on graphene surface and combination of oxygen ions into the graphene lattice.

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Effect of Different Conveyer Speed of Electron Beam Irradiation on the Oxidative and Microbiological Stability of Ground Pork during Refrigeration (Conveyer 이동 속도를 달리한 전자선 조사가 돈육의 냉장 중 산화와 미생물적 안정성에 미치는 영향)

  • Whang, Key
    • Food Science of Animal Resources
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    • v.23 no.1
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    • pp.50-55
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    • 2003
  • Fresh ground pork was irradiated with the electron beam(3.0 and 5.0 kGy) using 2 different conveyer speeds (10 and 20 ㎐), respectively, in order to determine the effect of conveyer speeds on the development of lipid oxidation and microbial stability. During refrigerated storage, the development of lipid oxidation decreased significantly (p<0.05) with the increase in the electron beam conveyer speed from 10 to 20 ㎐. The ground pork with electron beam inhibited the growth of total aerobic bacteria and mesophiles. The inhibitory effect increased when the electron beam dose increased from 0 to 5.0 kGy. The finding that higher speed(20 ㎐) of electron beam had some antioxidative effect is very promising, however, other means to control the lipid oxidation must also be employed to fully utilize the sterilization effect of electron beam in ground pork.

Comparision of Wear Characteristics of Automobile Transmission Gear on Surface Modification (표면개질을 달리한 자동차 변속기어의 마멸특성 비교)

  • Ryu Ul-Hyun;Cho Yon-Sang;Kim Young-Hee;Park Heung-Sik
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2003.11a
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    • pp.299-306
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    • 2003
  • The SCM420 used mainly to automobile transmission gear has problems that it costs transmission gear maker much money in carburizing treatment. For this, it needs to alternate the existing material and heat treatment to new gear material and surface modification. For this, friction and wear experiment according to sliding speed and applied load was carried out to evaluate the wear resistance of two transmission gear materials with oxidation nitrocarburising and non-oxidation nitrocarburising NT100, The presumed wear volume was calculated with the image processing for evaluation of wear resistance of two transmission gear materials. The results show that the oxidation nitrocarburising has a distinguished wear resistance than non-oxidation nitrocarburising.

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Selective Laser Sintering of WC-Co Mixture (텅스텐 카바이드와 코발트 혼합물의 선택적 레이저 소결)

  • 김광희;조셉비만
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2001.10a
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    • pp.269-274
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    • 2001
  • This paper describes the experimental results on direct selective laser sintering of WC-Co mixture. The experiments were carried out within an air, argon and nitrogen atmosphere. The main problem occurred during sintering within an air atmosphere was oxidation of WC-Co mixture. As the power of laser is increased and scanning speed is decreased, more severe oxidation takes place. Within an argon and nitrogen atmosphere the oxidation is reduced significantly. As the energy density is increased the thickness of the sintered layer is increased.

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