• Mycobiology
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• 제30권4호
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• pp.228-232
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• 2002

This study focused on the production of high quality compost for the growth of aero-thermophilic fungi, which has a promoting effect on the growth rate and production of oyster mushrooms. The automated solid-state bioreactor system was designed on the basis of a Three-Phase-One system, which controls the serial steps of prewetting, pasteurization and fermentation processes. High numbers of thermophilic fungi and bacteria were recovered from the mushroom composts prepared by this solid-state bioreactor. The rates of composting process were depended on physical as well as chemical factors. Among these factors, the parameters of moisture content and temperature were found to be particularly important. In our automated system, constant levels of moisture content, temperature and ventilation via mixing were provided by a centralized control apparatus including PLC, water tank and water jacket systems. These features induced higher microbiological activity of aero-thermophiles.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 추계 학술대회논문집
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• pp.27-31
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• 2007

Glass particle distribution in a stirred solid/liquid systems was investigated using computational fluid dynamics(CFD). The numerical results were compared to experimental data from the available literature which investigated the local dispersed phase volume fraction by means of an endoscope technique. Eulerian multi-phase model and applications considered high loading of solid particle was used to investigate the influence of the particle concentration and mixing tank size on the solid distribution. A good agreement was obtained between the experimental data and simulation results. The results showed different solid particle distribution in an agitator by particle concentration and mixer size.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2003년도 추계학술대회 논문집
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• pp.35-38
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• 2003

Simultaneous measurement of velocity and concentration fields in a stirred mixer flow using a combined Stereo-PIV/Planar-LIF technique is carried out. Instantaneous velocity fields and concentration fields represent the local flow characteristics. A baffle is perpendicularly attached to the Wall to remove inactive region which shows very slow dispersion. It is found that the baffle produces tip vortex and breaking the divided streamline, so that mixing efficiency could be increases significantly.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2006년도 전기학술대회논문집
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• pp.321-322
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• 2006

Industrial agitators are used in various industrial fields where they are necessary to intimately mix two reactants in a short period of time. However, despite their widespread use, complex unsteady flow characteristics of industrial agitators are not systematically investigated. The present study alms for clarify unsteady flow characteristics induced by various impellers in a tank. Impellers are pitched blade turbine(PBT) types, Screw type and Rushton turbine type. In this study flow characteristics of the impeller using CFD. The rotating speed of impellers fixed about 100RPM. These three types of Impeller show that typical flow characteristics of axial turbine and suitable for mixing powder

• JSTS:Journal of Semiconductor Technology and Science
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• 제9권3호
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• pp.153-159
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• 2009

A CMOS frequency synthesizer for $5{\sim}6$ GHz UNII-band sub-harmonic direct-conversion receiver has been developed. For quadrature down-conversion with sub-harmonic mixing, octa-phase local oscillator (LO) signals are generated by an integer-N type phase-locked loop (PLL) frequency synthesizer. The complex timing issue of feedback divider of the PLL with large division ratio is solved by using multimodulus prescaler. Phase noise of the local oscillator signal is improved by employing the ring-type LC-tank oscillator and switching its tail current source. Implemented in a $0.18{\mu}m$ CMOS technology, the phase noise of the LO signal is lower than -80 dBc/Hz and -113 dBc/Hz at 100 kHz and 1MHz offset, respect-tively. The measured reference spur is lower than -70 dBc and the power consumption is 40 m W from a 1.8 V supply voltage.

• Nuclear Engineering and Technology
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• 제44권8호
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• pp.831-846
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• 2012

KAERI has developed a two-phase CFD code, CUPID, for a refined calculation of transient two-phase flows related to nuclear reactor thermal hydraulics, and its numerical models have been verified in previous studies. In this paper, the CUPID code is validated against experiments on the downcomer boiling and moderator flow in a Calandria vessel. Physical models relevant to the validation are discussed. Thereafter, multi-scale thermal hydraulic analyses using the CUPID code are introduced. At first, a component-scale calculation for the passive condensate cooling tank (PCCT) of the PASCAL experiment is linked to the CFD-scale calculation for local boiling heat transfer outside the heat exchanger tube. Next, the Rossendorf coolant mixing (ROCOM) test is analyzed by using the CUPID code, which is implicitly coupled with a system-scale code, MARS.

• 한국시뮬레이션학회논문지
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• 제2권1호
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• pp.78-90
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• 1993

기존의 모의 실험언어를 이용해서 연속 체계를 모의 실험하는 것을 사용자가 언어에서 요구하는 형태로 모델을 형성해야 하는 어려움이 따른다. 따라서 본 연구에서는 사용자에게 최대한 편의성을 제공하는 연속체계 모의 실험언어인 PCSL (Postech Continuous -system Simulation Language)를 개발하였다. PCSL은 주어진 대상을 모델링한 미분방정식과 그것을 푸는데 필요한 여러 가지 제약 사항으로 이루어진 간단한 프로그램을 입력으로 받아 자동으로 모의 실험을 수행함으로서 사용자의 노력이 최소화하게 된다. PCSL 처리 시스템의 구성은 주어진 모델을 C 프로그램으로 변형하는 변환기, 모의 실험 알고리즘을 구현한 C 프로그램을 생성하는 생성기, 모의 실험을 수행하는 실행기, 사용자 인터페이스 등으로 되어있다. 구현 예로는 먼저 선형 상미분방정식의 예로 mass-damper-spring system, 비선형 상미분방정식의 예로 van der Pol 방정식, 연립 상미분방정식의 예로는 mixing tank problem 등을 보였다.

• 한국CDE학회논문집
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• 제11권5호
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• pp.359-364
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• 2006

Industrial Agitators are used in various industrial fields where they are necessary to intimately mix two reactants in a short period of time. However, despite their widespread use, complex unsteady flow characteristics of industrial mixers are not systematically investigated. The present study aims for clarify unsteady flow characteristics induced by various impellers in agitator's tank. Impellers are Pitched blade turbine(PBT) types, Screw type and Rushton turbine type(RUT). In this study is numerical analysis of the Industrial agitator's Impeller types. The rotating speed of impellers fixed about 100RPM. Numerical analysis results show that differential flow characteristics of each type Impeller and Rushton turbine type(RUT) is suitable for mixing powder.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.678-683
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• 2003

Mixers are used in various industrial fields where it is necessary to intimately mix two reactants in a short period of time. However, despite their widespread use, complex unsteady flow characteristics of industrial mixers are not systematic investigated. The present study aimed to clarify unsteady flow characteristics induced by various impellers in a tank. Impellers are pitched blade turbine and neo-hydrofoil turbine types. A high speed CCD camera and an Ar-Ion laser for illumination were adopted to clarify the time-dependent flow characteristics of the mixers. The rotating speed of impellers increased from 6Hz to 60Hz by 6Hz. The maximum velocity around PBT impeller is higher than the hydrofoil type impeller. These two types of turbine shows that typical flow characteristics of axial turbine and suitable for mixing high -viscosity materials.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.811-813
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• 2008

To see the effect of magnesium on adhesion to natural zeolites, a series of batch tests were performed in this research. Mixed bacteria were sampled from the digestion tank at a local sewage treatment plant in Seoul. Magnesium-zeolites were synthesized by mixing natural zeolites with 0.096 M, 0.24 M, and 0.48 M of MgCl2 solution. For comparison, manganese and trivalent ferric zeolites were also prepared. Two grams of 0.2 mm $\sim$ 0.3 mm sized zeolites(non-treated, Mg, Mn and Fe(III) treated zeolites) and 20 mL of water were mixed in a Corex 25 mL tube. Five milliliters of culture solution including bacteria was added to the tube. The tubes were equilibrated in a shaking incubator at mesophilic temperature $(30{\pm}2^{\circ}C)$. The bacterial concentrations were measured with a Microluminometer (New Horizons 3550i) and total organic carbon (TOC) spectrophotometer (Multi NC-3100).