• 제목/요약/키워드: Reaction Front

검색결과 153건 처리시간 0.023초

수소생산을 위한 디젤 개질용 촉매와 반응특성에 관한 연구 (Study on Reaction Characteristics and Catalysts to Reform Diesel for Production of Hydrogen)

  • 강인용;배중면
    • 전기화학회지
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    • 제8권1호
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    • pp.12-16
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    • 2005
  • 디젤은 높은 volumetric density$[VD,\;kg\;H_2/m^3]\;(>100)$와 gravimetric density$(GD,\;\%\;H_2)\;(>17)$를 가지는 우수한 수소저장매체 중의 하나이다. (Liquid Hydrogen의 경우 VD와 GD가 각각 50, 18 정도) 본 연구는 이러한 디젤연료의 개질에 적합한 촉매선정 및 반응특성에 관한 연구를 실시하였다 촉매는 자체 선정한 3가지 촉매(NECS-1, NECS-2, NECS-3)와 2가지 상용촉매(FCR-HCl4, FCR-HC35. Sud-Chemie, Inc)에 대하여 조사하였다. 실험결과 NECS-1이 디젤개질에 가장 적합한 것으로 판단되었다. 이와 함께 촉매 층의 길이에 따른 온도 및 농도를 분석하였으며, 디젤개질을 위한 연료의 delivery 문제로 인한 촉매 층 내의 급격한 온도 변화특성을 확인할 수 있었다. 또한 촉매 층 상단부에서 발생한 발열량을 하단부의 흡열부에 효과적으로 전달하는 것이 ATR(Autothermal Reforming) 반응 특성에 깊게 연관되어 있음을 확인할 수 있었다.

시각 되먹임을 이용한 앉은 자세에서 일어서기 시 몸통의 동작과 지면 반발력에 미치는 영향 (The Effects of Trunk Movement and Ground Reaction Force during Sit to Stand Using Visual Feedback)

  • 고영건;오태영;이재호
    • 대한통합의학회지
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    • 제11권2호
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    • pp.207-219
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    • 2023
  • Purpose : This study was conducted to investigate the changes in trunk movement and ground reaction during sit to stand motion using visual feedback. Methods : Fifteen adults (average age: 23.53±1.77 years) participated in this study. An infrared reflective marker was attached to the body each participant for motion analysis, and the participants performed sit to stand motion while wearing a hat attached with a laser pointer, which provided visual feedback. First, the sit to stand action was repeated thrice without obtaining any visual feedback, followed by a three minute break. Next, the laser pointers attached to hats were irradiated on a whiteboard, located at a distance of 5 m in front of the chairs, on which the participants sat; a baseline was set, and the participants performed stand up movements three times under this condition. A visual feedback was provided to the participants to prevent the laser pointers from crossing the set baseline. During each stand-up movement, the position of the reflective marker attached to the subject's body was recorded in real time using an infrared camera for motion analysis. The trunk movement and ground reaction force were extracted through recorded data and analyzed according to the presence or absence of visual feedback. Results : The results indicated that in the presence of a visual feedback during the sit-to-stand movements, the range of motion of the trunk and hip joints decreased, whereas that of the knee and ankle joints increased in the sagittal plane. The rotation angle of the trunk in the horizontal plane decreased. The left and right movement speed of the center of pressure increased, the pressing force decreased, and the forward and backward movement speed of the trunk decreased. Conclusion : The results suggest that the efficiency and stability of the stand up movement of a body increase when a visual feedback is provided.

연속적 폭굉속도 측정 시스템을 이용한 테르밋 반응 혼합물의 연소전파속도 측정에 관한 연구 (Determination of Combustion Propagation Velocity of Thermite Reaction Mixture Using Continuous VOD Measurement System)

  • 김민성;강형민;정상선;정윤영;박훈;조상호
    • 화약ㆍ발파
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    • 제33권3호
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    • pp.21-28
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    • 2015
  • 본 연구의 목적은 연속적 폭굉속도(VOD) 측정시스템을 이용하여 상용 테르밋 반응 혼합제의 연속적인 연소전파거동을 측정하기 위한 방법을 제안하기 위함이다. 두 종류의 상용 VOD 센서(VOD PROBEROD-OS, VOD PROBEROD-HS)와 자체개발한 VOD 센서(VOD PROBEROD-ES)를 기존 연속적 VOD 측정시스템에 적용하여 테르밋 반응과정에서 발생하는 연소전파속도(VOC)를 측정한 결과, 자체 개발한 VOD PROBEROD-ES 센서만 정상적인 연속적 연소전파거동을 보여주었다. 결과적으로, 철재튜브 내 장전된 테르밋 반응 혼합제는 기폭점으로부터 100mm 이내에서 약 200m/s의 연소전파속도를 보였으며, 100mm와 300mm 구간에서 급작스럽게 증가하여 음속의 2배에 가까운 VOC를 나타내었다. 그 이후 서서히 증가하여 최종적으로 800m/s까지 증가하는 경향을 보였다. 이러한 결과는 테르밋 반응 혼합제를 이용하여 정상적인 VOC나 위력을 기대하기 위해서는 철재튜브 등으로 완전히 구속된 상태에 길이 300mm 이상 장전하여야 함을 의미한다.

상용 한약재의 부작용에 관한 연구 (A Study on the Side Effect of Crude Drugs)

  • 안덕균;김찬수
    • 생약학회지
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    • 제14권3호
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    • pp.102-106
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    • 1983
  • As many crude drugs are used in the oriental medical field problems on the side effects of these drugs come to the front. To conduct delayed-type hypersensitivity we selected 29 kinds of drugs used frequently for therapeutic agents in oriental medical hospitals (Table I). The cell-mediated immune response was evaluated by measuring the foot pad swelling reaction and humoral immune response by measuring the antibody formation to these crude drugs. Mice were given these drugs intraperioneally for sensitization and challenged with same drug as used for sensitization respectively by intral dermal injection on the left and righ hind foot pad 4 days after senstization and then the foot pads were measured with the dial micrometer. The results were as follow; 1) Gentianae Scabrae Radix, Arecae Semen, Corydalis Tuber, and Paeoniae Radix were significant as delayed-type hypersensitivity inducers. 2) None of the crude drugs tested had effect on the induction of humoral immune response.

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Quasi-steady State Simulation of Rotating Detonation Engine

  • Niyasdeen, Mohammed;Oh, Sejong;Kim, Kui Soon;Choi, Jeong-Yeol
    • International Journal of Aeronautical and Space Sciences
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    • 제16권4호
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    • pp.548-559
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    • 2015
  • We performed a numerical simulation based on the two-dimensional (2-D) unsteady Euler's equation with a single-step Arrhenius reaction model in order to investigate the detonation wave front propagation of an Argon (Ar) diluted oxy-hydrogen mixture ($2H_2+O_2+12Ar$). This simulation operates in the detonation frame of reference. We examine the effect of grid size and the performance impact of integrated quantities such as mass flow. For a given set of baseline conditions, the minimal and maximum grid resolutions required to simulate the respective detonation waves and the detonation cell structures are determined. Tertiary shock wave behavior for various grids and pre-exponential factors are analyzed. We found that particle fluctuation can be weakened by controlling the mass flow going through the oblique shock waves.

휠로더의 3 차원 모델링 및 시뮬레이션 (Three Dimensional Modeling and Simulation of a Wheel Loader)

  • 박준용;유완석;김희원;홍제민;고경은
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2004년도 춘계학술대회
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    • pp.870-874
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    • 2004
  • This paper presents a three dimensional modeling and simulations of operation and running of a wheel loader using the ADAMS program. A wheel loader consists of a bucket, a boom, a crank, a front frame, a rear frame, a bucket cylinder, two boom cylinders, two steering cylinders, nine spherical joints, six universal joints, five translation joints, three inline joints, a revolute and a fixed joint. Judging from the actual degrees of freedom of the wheel loader, proper kinematic joints are selected to exclude redundant constraints in the modeling. Through the running simulation over a bump with the three dimensional modeling, the joint reaction forces are calculated.

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A Development of a Transient Hydrogen Generation Model for Metal-Water Interactions

  • Lee, Jin-Yong;Park, Goon-Cherl;Lee, Byung-Chul
    • Nuclear Engineering and Technology
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    • 제32권6호
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    • pp.549-558
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    • 2000
  • A transient model for hydrogen generation in molten metal-water interactions was developed with separate models for two stages of coarse mixing and stratification. The model selves the mechanistic equations (heat and mass transfer correlation, heat conduction equation and the concentration diffusion equation) of each stage with non-zero boundary conditions. Using this model, numerical simulations were performed for single droplet experiments in the Argonne National Laboratory tests and for FITS tests that simulated dynamic fragmentation and stratification. The calculation results of hydrogen generation showed better agreement to the experiment data than those of previous works. It was found from the analyses that the steam concentration to be reached at the reaction front might be the main constraint to the extent of the metal droplet oxidized. Also, the hydrogen generation rate in the coarse mixing stage was the higher than that in the stratification stage. The particle size was the most important factor in the coarse mixing stage to predict the amount of hydrogen generation.

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CFD를 활용한 DOC-DPF 조합의 유동 균질도 분석 (Flow Uniformity Analysis of DOC-DPF System using CFD)

  • 김태훈;박성욱
    • 한국분무공학회지
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    • 제24권3호
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    • pp.122-129
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    • 2019
  • Flow uniformity in aftertreatment system is an important factor in determining uniform catalytic reaction and filtration. In this study, variety types of DOC-DPF system design were analyzed to increase flow uniformity. For this analysis, ANSYS Fluent was used with porous media setup for DOC and DPF. Turbulent flow was modeled by standard $k-{\varepsilon}$ model excepting porous media. Uniformity index was utilized to evaluate the flow uniformity quantitatively. Reference design showed low velocity region because two large vortex were generated before baffle. When radius of DOC-DPF system was increased, exhaust pressure acting on the inlet decreases and velocity distribution was shifted to one side. When inlet pipe was set to axial center of DOC-DPF system velocity distribution was symmetric. However, flow was not dissipated until the front end of DOC and showed higher uniformity index. When the volume of DOC was reduced while fixed volume of entire DOC-DPF system and baffle plate is located downstream of the DOC-DPF system, there was improvement in uniformity index.

심박 변이도 분석을 통한 전중혈(膻中穴) 압진(壓診)과 자율신경실조의 상관성 연구 (Study of the Relation between Palpation of the Jeonjung(膻中, $CV_{17}$) and Autonomic Nerve System by Heart Rate Variability)

  • 하선윤;조성연;장진영;김용석;남상수
    • Journal of Acupuncture Research
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    • 제26권5호
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    • pp.57-63
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    • 2009
  • Objectives : Since the Front Points are treated as response zone, it can be used for the diagnosis and treatment of disease in viscera and bowels. Jeonjung($CV_{17}$) is the Front Point of SIMPO, it is related with cardiovascular, neuro-psychiatrical disease in aspect of Oriental Medicine. This research is for clarifying relations with palpation of the Jeonjung($CV_{17}$) and autonomic nerve system by comparing HRV and SRI(Stress Reaction Index). Methods : This study was proceeded for three months, from June 2009 to September 2009. Among 31 healthy volunteers, 13 subjects who complained the pressure pain around Jeonjung($CV_{17}$) are classified pressure pain group and 18 subjects who had no pain around Jeonjung($CV_{17}$) as normal group. All subjects had their HRV(SA-2000E: Medicore Co..Ltd. Korea) and SRI measured at visit. We studied the difference of HRV between two groups.(Statistics by Student t-test, p<0.05) Results : LF normalization of the pressure pain group were significantly higher than those of the normal group. HF normalization of the pressure pain group were significantly lower than those of the normal group. Compared with those of the normal group, total SRI of the pressure pain group were low but it's not significant. Conclusions : The results of HRV of the pressure pain group show that pressure pain around Jeonjung($CV_{17}$) is related to mental stress and autonomic disturbance.

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전기뱀장어의 전기발생을 모사한 고전압 액체 전해질 미소전지 (High-Voltage Liquid-Electrolyte Microbatteries Inspired from Electric Eels)

  • 김문철;조영호
    • 대한기계학회논문집A
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    • 제33권5호
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    • pp.469-473
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    • 2009
  • We present high-voltage liquid-electrolyte microbatteries, inspired from the high-voltage generation mechanism of electric eels using serially connected multiple-cell arrays. In the microbatteries, we purge air into the electrolyte filled in a channel layer to isolate serially connected multiple cell arrays using three surface-tension valves (cell-front, outlet, and cell-end valves). Compared to the previous multi-cell stack or interconnection, present microbatteries provide a reduced multi-cell charging time. We have designed and characterized four different prototypes C1, C10, C20, and C40 having 1, 10, 20, and 40 cells, respectively. In the experimental study, the threshold pressures of cell-front, outlet, and cell-end valves were measured as $460{\pm}47$, $1,000{\pm}53$, and $2,800{\pm}170$ Pa, respectively. The average charging time for C40 was measured as $26.8{\pm}4.9$ seconds where the electrolyte and air flow-rates are 100 and $10{\mu}l/min$, respectively. Microbatteries showed the maximum voltage of 12 V (C40), the maximum power density of $110{\mu}W/cm^2$ (C40), and the maximum power capacity of $2.1{\mu}Ah/cm^2$ (C40). We also proposed a tapered-channel to remove the reaction gas from the cell chamber using a surface tension effect. The present microbatteries are applicable to high-voltage portable power devices.