• 제목/요약/키워드: Various Temperature Condition

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니켈 촉매를 이용한 프로판 예개질 반응의 탄소침적에 대한 연구 (Carbon Deposition on Nickel Catalyst for Pre-reforming of Propane)

  • 김선영;배중면
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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    • pp.487-490
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    • 2008
  • Temperature programmed oxidation (TPO) is used to characterize coke species deposited on commercial nickel catalyst, C11-PR during propane pre-reforming. Propane pre-reforming performed under various condition, S/C from 1.5 to 2.5 and temperature from $350^{\circ}C$ to $450^{\circ}C$. There are three kinds of coke species detected by TPO: (i) reactive coke, (ii) coke deposited on metal site and (iii) coke deposited on acid support. Coke deposited on metal and support are minimized although reactive coke is generated at temperature of $400^{\circ}C$ and S/C of 2.0. Reactive coke is expected to remove easily below temperature of $200^{\circ}C$. Therefore, optimized pre-reforming condition for propane is $400^{\circ}C$ and S/C of 2.0.

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반도체 표면처리공정용 대면적 히터 플레이트의 열전달 특성에 관한 연구 (A Study on the Heat Transfer Characteristics of the Large Dimension Heater Plate for a Semiconductor Process)

  • 이윤용;강환국;문석환
    • 한국표면공학회지
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    • 제43권6호
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    • pp.309-314
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    • 2010
  • The numerical study for the effect of various factors that affect the temperature distribution of the process glass installed above the large rectangular heater plate was carried out. For the calculation, heat flux, distance between heat source and process glass plate, effect of vacuum condition and convection in a chamber were considered as important factors. The results showed that the temperature gradient on the glass was increased at the natural convection because of the buoyancy force increases due to the heated air. Also, the more heat flux and distance between the heater plate and glass increases, the more increasing the temperature gradient was. In the case of isothermal heating wall, the temperature variation was smaller than the uniform heat flux condition.

pH, 온도 및 시간이 수산화인회석의 합성에 미치는 영향 (THE EFFECTS OF pH, TEMPERATURE AND TIME ON THE SYNTHESIS OF HYDROXYAPATITE)

  • 이희주;허복
    • Restorative Dentistry and Endodontics
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    • 제19권1호
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    • pp.27-44
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    • 1994
  • The purpose of this study was to determine the effects of pH, temperature and time on the synthesis of hydroxyapatite(HAP) by spontaneous precipitation under relatively physiologic condition. Specimens were obtained from aqueous system with various pH, temperature and experimental time. Chemical composition, crystallographic structure and crystallinity of the synthetic HAP were evaluated by Infrared spectroscopy and powdered X-ray diffraction method. The following results were obtained. 1. No precipitate was obtained under pH 5.5. 2. All the specimens were concluded as HAP except one that was obtained under the condition of pH 6.5, $25^{\circ}C$ and 1 day. It was concluded as dicalcium phosphate dihydrate(DCPD). 3. The crystallinity of HAP was enhanced by increases in pH, temperature and time of the preparation. But, the crystallinity of the synthetic HAP was lower than that of the mineral HAP. 4. Intermediates such as DCPD and octacalcium phosphate were formed on the process of the synthesis of HAP.

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L-LINK를 이용한 S.I.엔진 피스톤 각 부위의 온도측정에 대한 실험적 연구 (An experimental study on piston temperature measurement at various locations in a S.I. engine utilizing L-LINK mechanism)

  • 김승수;김지연
    • 오토저널
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    • 제9권3호
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    • pp.55-65
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    • 1987
  • This paper presents the method of piston temperature measurement and its data under various engine operating conditions. In case of high speed engine, the thermocouple wires must be guided from moving piston to stationary place with carful attention. for this purpose L_LINK SYSTEM was made and assembled to a passenger car engine on the test bench and then the piston temperature was successfully measured. The tested engine speed ranged from 1,000 to 4,000 rpm with 500 rpm increments. Not only the effects of engine speed and load on the piston temperature but those of spark timing, detonation, coolant temperature and Reynolds number based on inlet air condition were studied form the measurement obtained by this L_LINK SYSTEM.

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Effect of Light, Temperature, and Shaking Speed on Production of Capsaicin in Suspension-Cultured Jalapeno Pepper (Capsicum annuum L.)

  • Lee, Kwon-Bok;Engler, Cady;Yang, Jae E.;Lee, Shin-Woo;Park, Yong-Ha
    • Journal of Applied Biological Chemistry
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    • 제44권2호
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    • pp.84-86
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    • 2001
  • Capsaicin synthesis by suspension cultured cells of Jalapeno pepper (Capcicum annuum L.) was assessed in vitro under various conditions including temperature (23 and $30^{\circ}C$), light intensity (with light and without light), and shaking speed (110 and 200 rpm). Capsaicin production increased, while the cell biomass growth decreased possibly due to the production of a secondary metabolite. Capsaicin synthesis was primarily affected by light condition. Cells cultivated at 110 rpm and $23^{\circ}C$ under light condition yielded the highest fresh weight, while those cultivated under the same condition, but without light resulted in the lowest cell mass. Capsaicin content in cells of 18-day-old pepper grown at 110 rpm and $23^{\circ}C$ under light was 0.125% of the cell mass. However, without light treatment, the capsaicin content in cells at the same shaking speed and temperature increased up to 169%, indicating no light is favored in the capsaicin synthesis by Jalapeno pepper. Increasing the shaking speed from 110 to 200 rpm without light enhanced the capsaicin synthesis. Results of this study demonstrate that light condition is the limiting factor in the synthesis of capsaicin in tissue-cultured Jalapeno pepper cells.

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Ag-CdO계 전기접점재료의 미세조직에 미치는 열처리 조건과 산화 공정의 영향 (The Effect of The Heat Treatment Condition and the Oxidation Process on the Microstructure of Ag-CdO Contact Materials)

  • 권기봉;남태운
    • 한국주조공학회지
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    • 제25권6호
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    • pp.226-232
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    • 2005
  • Contact material is widely used in the field of electrical parts. Ag-CdO material has a good wear resistance and stable contact resistance. In order to establish optimizing heat treatment condition, rolling temperature and oxidation process, we studied the microstructure of Ag-CdO material with various conditions. The experimental procedure were melting using high frequency induction, heat treatment, rolling and internal oxidation. And we experimented on difference process, Post-oxidaion. In this study, we obtained the optimizing heat treatment condition was $700^{\circ}C$ for 15 min. and the optimizing rolling temperature was $730^{\circ}C$. In investigation of the microstructure of oxidized material, coarse oxide and depleted oxidation layer existed. The hardness was average Hv 70. When we used Post-oxidation, oxides were finer than prior process and depleted oxidation layer did not exist. The hardness of Post-oxidation material was average Hv 80. And the optimizing rolling temperature was $800^{\circ}C$.

금형주조한 Mo-Ni-Cu계 구상흑연주철의 오스템퍼링 온도 및 시간에 따른 파괴특성 (Fracture Properties of Mo-Ni-Cu Austempered Ductile Iron Cast in Permanent Mold with Austempering Temperature and Time)

  • 이영상;강인찬
    • 한국주조공학회지
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    • 제11권4호
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    • pp.331-337
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    • 1991
  • Various test specimens were prepared by austempering low alloyed Mo-Ni-Cu ductile iron blocks of high graphite nodule count at 270, 320 or $370^{\circ}C$ for 0.5, 1, 3 or 9hrs. Tensile test, CVN impact test and plane-strain fracture toughness test(compact tension specimen of 50mm W) were done for each heat treatment condition at room temperature. X-ray diffractometer and optical microscope were used to investigate the change of microstructure and relationships between microstructure and test results. The highest retained austenite volume percent at each austempering temperature was corresponded to the highest mechanical property. The highest elongation value of 17%, U.T.S. value of 1,600 MPa or $K_{IC}$ value of 90MPa${\surd}$m were reached at each optimum condition. The best heat treatment condition for fracture toughness were 3hrs' holding time combined with the austempering temperature of 270 and $320^{\circ}C$, and 1hr's of $370^{\circ}C$.

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시차주사열량측정법에 의한 니켈기 초내열 합금의 열분석 (Thermal Analysis of Nickel-Base Superalloys by Differential Scanning Calorimetry)

  • 윤지현;오준협;김홍규;윤존도
    • 한국재료학회지
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    • 제26권5호
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    • pp.235-240
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    • 2016
  • Appropriate thermo-mechanical properties of nickel-based superalloys are achieved by heat treatment, which induces precipitation and solid solution hardening; thus, information on the temperature ranges of precipitation and dissolution of the precipitates is essential for the determination of the heat treatment condition. In this study, thermal analyses of nickel-based superalloys were performed by differential scanning calorimetry method under conditions of various heating rates of 5, 10, 20, or 40K/min in a temperature range of 298~1573K. Precipitation and dissolution temperatures were determined by measuring peak temperatures, constructing trend lines, and extrapolating those lines to the zero heating rate to find the exact temperature under isothermal condition. Determined temperatures for the precipitation reactions were 813, 952, and 1062K. Determined onset, peak, and offset temperatures of the first dissolution reaction were 1302, 1388, and 1406K, respectively, and those values of the second dissolution reaction were 1405, 1414, and 1462K. Determined solvus temperature was 1462K. The study showed that it was possible to use a simple method to obtain accurate phase transition temperatures under isothermal condition.

전남지방 전통주택 하절기와 동절기의 온습도 평가에 관한 실험적 연구 (An Experimental Study on the Temperature and Humidity Evaluation in the Summer and Winter Season of the Korean Traditional Houses in Chonnam Province)

  • 이태강;최은석;김항;김형렬;기노갑;김선우
    • KIEAE Journal
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    • 제6권1호
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    • pp.57-62
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    • 2006
  • Korean Traditional houses has been evolved and developed in many years, adopting the natural environment to control exterior conditions. These control method are various passive system of using natural materials, considering micro climate, building lay out, and these system are more natural and ecological to make the comfortable indoor climate than active systems of the present houses. This study aims to analyzed control performance of outdoor environment of five Korean traditional houses during the summer and winter. These houses are varied with lay out and floor plan to reflect the way of control for environmental condition, surveyed the reverberation time and sound level difference between rooms of the main living room and other main floored room, master room and kitchen. Especially air temperature and humidity have been measured simultaneously in each rooms to compare with outdoor condition. As a result, the variation of air temperature and humidity of most rooms are considerably static while condition of outdoors are much varied, it is showed that indoor climate has been controled with traditional soiled walls.

순간 해석 기법을 이용한 PVT 잔량 측정법의 극저온 균일 온도 조건에서의 실험적 연구 (Experimental research of Pressure-Volume-Temperature mass gauging method using instantaneous analysis under cryogenic homogeneous condition)

  • 서만수;정상권;정영석;구동훈;지동진
    • 한국초전도ㆍ저온공학회논문지
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    • 제14권1호
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    • pp.38-43
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    • 2012
  • In the extreme conditions of launch vehicle in a space, such as cryogenic temperature and low-gravity environment, the mass gauging of remaining propellants becomes a difficult problem. Pressure-volume-temperature (PVT) method is one of the attractive mass gauging methods under low-gravity due to its simplicity and reliability. PVT gauging experiment with various mass flow rates of helium injection is carried out with the experimental apparatus creating cryogenic homogeneous condition as the condition of low-gravity. Experimental results are analyzed by a novel PVT gauging analysis method which considers all instantaneous changes of pressure and temperature in the ullage volume with small time intervals. It is observed that the gauging error from the novel PVT gauging analysis is -0.11% with 2 slpm mass flow rate of helium injection.