• Title/Summary/Keyword: energy input

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Dry Fine Grinding of Rice Husk Ash using a Stirred Ball Mill (교반 볼밀을 이용한 왕겨재의 건식 미세분쇄에 관한 연구)

  • 박승제;최연규;김명호;이종호
    • Journal of Biosystems Engineering
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    • v.25 no.1
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    • pp.39-46
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    • 2000
  • This work was conducted to study the operating characteristics of a grinding system designed to obtain fine rice husk ash powder. To find better utilizing of rice husk, a valuable by-product from rice production, once the rice husk was incinerated and the thermal energy was recovered from the furnace, the ash was fed and pulverized in the grinding system resulting a fine powder to be used as a supplementary adding material to the portland cement manufacturing . The rice husk ash grinding system consisted of a high speed centrifugal fan for the preliminary coarse milling and a dry-type stirred ball mill for the subsequent fine grinding . Total grinding time 9 5, 15, 30, 45 min), impeller speed (250, 500, 750 rpm) , and mixed ratio (4.8, 7.9, 14.9) were three operating factors examined for the performance of a stirred ball mill used for the fine grinding of ash. With the stirred ball mill used in this study, the minimum attianable mean diameter of rice husk ash powder appeared to be 2 ${\mu}{\textrm}{m}$. During the find grinding, the difference in specific surface area of powder showed an increase and the grinding energy efficiency decreased with the increase in total grinding time, impeller speed ,and mixed ratio. For the operating conditions employed , the resulting mean diameter of fine ash powder, specific energy input, and grinding energy efficiency were in the range of 1.79 --16.04${\mu}{\textrm}{m}$, 0.072-5.226kWh/kg, an d1.11-12.15$m^2$/Wh, respectively. Grinding time of 30 min , impeller speed of 750 rpm, and mixed ratio of 4.8 were chosen as the best operating conditions of the stirred ball mill for fine grinding . At these conditions, mean particle diameter of the fine ash, grinding energy efficiency, grinding throughtput, and specific energy input were 2.73${\mu}{\textrm}{m}$, 3.95$m^2$/Wh, 0.25kg/h, and 1.22kWh/kg, respectively.

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A Study on Stirling Cryocooler for Precooling Hydrogen Liquefier (수소액화 예냉용 소형 스털링 극저온 냉동기 특성 연구)

  • PARK, SEONGJE;KO, JUNSEOK;HONG, YONGJU;KIM, HYOBONG;YEOM, HANKIL;IN, SEHWAN
    • Journal of Hydrogen and New Energy
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    • v.27 no.6
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    • pp.651-659
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    • 2016
  • Korea Institute of Machinery & Materials (KIMM) has developed a high efficient Stirling cryocooler with moving magnet linear compressor for precooling hydrogen liquefier and cooling high temperature superconductor (HTS) devices, such as superconductor cable and superconductor fault current limiters. Hydrogen liquefier and HTS electric devices require cryocooler with cooling capacity of hundred watts to kilowatts at 77 K. The compressor in the Stirling cryocooler uses opposed moving magnet linear motors to drive opposed pistons. High efficient Stirling cryocooler is designed by SAGE-software, manufactured and tested systematically. A cooling capacity of 1 kW at 77 K with an electric input power of 9.6 kW has been analyzed. But prototype test results of the Stirling cryocooler have the cooling capacity of 0.65 kW at 76.8 K with an electric input power of 8.1 kW. And then, 21.5% Carnot COP (Coefficient of performance) of the prototype Stirling cryocooler is achieved. The comparison analysis between SAGE-model and experimental results has shown the direction for further design optimization of the Stirling cryocooler.

Comparison of Sapphire and Germanium Fibers for Erbium : Yag Lithotripsy

  • Lee, Ho;Yoon, Ji-Wook;Jung, Young-Dae;Kim, Jee-Hyun;Ryan, Robert T.;Teichman, Joel M.H.;Welch, A.J.
    • Journal of the Optical Society of Korea
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    • v.12 no.4
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    • pp.309-313
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    • 2008
  • We studied the sapphire and germanium fibers to determine which optical fiber best transmits Erbium:YAG laser for intracorporeal lithotripsy. Human calculi were ablated with an Erbium:YAG laser in contact mode using two fibers. Optical outputs at the distal end of fibers were measured before and after laser lithotripsy. Upon the irradiation on the calculus with the 50 mJ and 100 mJ pulse energy, the output energy at the distal end of germanium fiber declined to approximately 50% of the input energy. For the sapphire fiber, the output energy at the distal end remained unchanged with 100 mJ input energy; however the output energy had dropped to 50% for 200 mJ input energy. In order to examine how the types of target tissue affect the fiber damage, the sapphire fiber was tested for the irradiation on soft tissue and water as well. No energy decline was observed during soft tissue and water irradiation. We also characterized ablation craters with both optical fibers. Both fibers produced similar craters on calculi in terms of depth and diameter. Sapphire fibers are better suited than germanium fibers for Erbium:YAG lithotripsy in terms of the fiber damage.

Nonlinear Control of an Input-Constrained Inverted Pendulum (입력제약을 고려한 도립진자의 비선형 제어)

  • Jung, Jae-Hoon
    • Proceedings of the KIEE Conference
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    • 2003.11b
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    • pp.119-122
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    • 2003
  • The aim of this paper is to propose a nonlinear controller for a single cart-type inverted pendulum using energy-based control scheme. Using a nonlinear model relating the angular position and velocity to the control input and a nonlinear controller is designed to regulate the angular position and velocity in the presence of input constraints. It is proved that the angular position and velocity converge to zero.

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Long-term Energy Systems Otimization Study (장기 에너지 수급체계화 연구)

  • 김풍일
    • Journal of the Korean Operations Research and Management Science Society
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    • v.4 no.2
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    • pp.35-39
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    • 1979
  • In order to recommend future national policy directions on energy supply and consumption and to suggest energy technological priorities to be developed, comprehensive energy models have been developed through this study in a sense of strategic and systematic approach. The “energy input-output model” has been formulated to analyze the mutual impacts between energy consumption patterns and industrial structures and to calculate energy intensities of industrial sectors. The long-term energy demands to the year 2000 were forecasted by using multi-regressional method and the optimal energy flow balances for five-year interval have been studied by using the “energy linear programming model” being took full account of interfuel substitutability and technology.

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Generation of the Input Profile for Fatigue Vibration Testing in MAST System (자동차부품(시트,도어) 6축 진동 재현을 위한 가진 프로파일 생성 기법)

  • Kim, Chan-Jung;Beak, Gyoung-Won;Lee, Bong-Hyun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2005.05a
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    • pp.413-418
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    • 2005
  • Vibration test using the MAST(Multi Axial Simulation Table) is more reliable test than conventional testing process focused on one directional vibration test. The former test could be possible with a advanced control algorithm and hardware supports so that most of the operation is automatically conducted by MAST system itself except the input information that is derived from the measured data. That means the reliability of the vibration test is highly depended on the input profile than any other cases before. In this paper, the optimal algorithm based on energy method is introduced so that the best combination of candidated input PSD data could be constructed. The optimal algorithm renders time information so that the vibration fatigue test is completely possible for any measured signals one wants. The real road test is conducted in short intervals containing some rough roads and the candidated input PSD is obtained from the extra road in proving ground. The testing is targeted for the electronically operated door and seat.

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A Single-Stage LED Tube Lamp Driver with Input-Current Shaping for Energy-Efficient Indoor Lighting Applications

  • Cheng, Chun-An;Chang, Chien-Hsuan;Cheng, Hung-Liang;Chung, Tsung-Yuan;Tseng, Ching-Hsien;Tseng, Kuo-Ching
    • Journal of Power Electronics
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    • v.16 no.4
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    • pp.1288-1297
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    • 2016
  • This study proposes a single-stage light-emitting diode (LED) tube lamp driver with input-current shaping for T8/T10-type fluorescent lamp replacements. The proposed AC-DC LED driver integrates a dual-boost converter with coupled inductors and a half-bridge series-resonant converter with a bridge rectifier into a single-stage power conversion topology. This paper presents the operational principles and design considerations for one T8-type 18 W-rated LED tube lamp with line input voltages ranging from 100 V rms to 120 V rms. Experimental results for the prototype driver show that the highest power factor (PF = 0.988), lowest input current total harmonic distortion (THD = 7.22%), and highest circuit efficiency (η = 92.42%) are obtained at an input voltage of 120 V. Hence, the proposed driver is feasible for use in energy-efficient indoor lighting applications.