• Title/Summary/Keyword: Generation Rates

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Generation of 5-axis NC Data for Machining Turbine Blades by Controlling the Heel Angle (Heel angle 조정에 의한 터빈 블레이드의 5축 NC가공 데이터 생성)

  • 이철수;박광렬
    • Korean Journal of Computational Design and Engineering
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    • v.4 no.2
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    • pp.110-120
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    • 1999
  • In general, turbine blades are usually machined on 5-axis NC machine. The 5-axis machining of sculptured surface offers many advantages over 3-axis machining including the faster material-removal rates and an improved surface finish. But it is difficult and time-consuming to generated interference-free 5-axis tool path. This paper describes research on the algorithm for generation of an interference-free 5-axis NC data for machining turbine blades. The approach, using the section profile derived from the intersection of cutting planes with a triangulated-surface approximation, includes (1) CL-data generation by detecting an interference-free heel angle (2) the calculation method for finding a adaptive feed-rate value, and (3) the inverse kinematics depending on the structure of 5-axis machine.

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Remote On-line Determination of the Load Rate Limit of Generation in AGC (AGC 운용에 있어서의 원격 On-line 최대 증감발율 취득 기법)

  • Kwon, Soon-Man;Jeon, Dong-Hoon;Moon, Won-Yong;Kim, Suk-Joo
    • Proceedings of the KIEE Conference
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    • 2000.11a
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    • pp.119-121
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    • 2000
  • The possibility of a remote on-line determination of the maximum load rates that are basically set at generation plants is investigated in automatic generation control (AGC) system. Energy management system (EMS) generates a test input to a remote power plant to get the samples of the generator output. Then from the samples it can be attempted to determine an approximate value of the load rate limit set by the operator. It is shown in computer simulation that in actual power plants the limit can be approximately determined from the input-output characteristics of the plants for a unit-step input.

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IO BOARD DESIGN OF NEXT GENERATION SATELLITE USING THE SPACE WIRE INTERFACE

  • Kwon Ki-Ho;Kim Day-Young;Choi Seung-Woon;Lee Jong-In
    • Bulletin of the Korean Space Science Society
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    • 2004.10b
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    • pp.223-226
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    • 2004
  • This paper presents a feasibility study of an advanced IO board design for the next generation of low-earth orbit satellites. Advanced IO board design includes sensor interface, NO, D/A, Digital Module, Serial Module etc, and allows to process increasing data rates between IO board and CPU board. The higher data rate involved in modem IO board additionally introduce issues such as noise, fault tolerance, command and data handling, limited pin count and power consumption problems. The experience in KOMPSAT-l and 2 program with this kind of problems resulted in using SMCS chip set, a high speed serial link technology based on IEEE-1355 (Space Wire Protocol) (ESA-ESTEC 2003, Parkes 1999), as a standard for next generation of satellite IO board design.

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A Study on the Needs of Apartmnent Residents for Community Programs by Different Generations (아파트 거주자들의 세대별 특성에 따른 생활관리 프로그램 요구도)

  • Kang, Soon-Joo;Kwon, Oh-Jung;Kim, Jin-Young;Kim, Jin-Young
    • Proceeding of Spring/Autumn Annual Conference of KHA
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    • 2005.11a
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    • pp.51-56
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    • 2005
  • The purpose of this study was to examine the needs of apartment residents for community programs by generations. For this study, the data from the focus group interview(35 participants) and the questionnaire survey(186 participants) were analyzed. The major results were as follows; 1) The residents in different generations had different characteristics and life values. Y generation showed higher value in Technology/Consumption/Individual than other generations. BB generation had higher value both in Health/Property/Family and Prudence/Reality. G generation scored a higher level in Tradition/Conservatism. 2) The residents in all generations showed a high level in needs of community programs and especially higher rates in needs of communication programs items. However, there were gaps in program needs among different generations. Therefore, the community programs should be specialized provided by considering unique needs of different generations.

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Estimating generation capacity of geothermal power generation pilot plant project (우리나라 지열발전 pilot plant 프로젝트의 발전량 추정)

  • Song, Yoonho;Lee, Tae Jong;Yoon, Woon Sang
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.05a
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    • pp.197.1-197.1
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    • 2011
  • Target generation capacity of geothermal power generation pilot plant project through the Enhanced Geothermal Systems (EGS) with a doublet system down to 5 km depth was estimated. Production and re-injection temperatures of geothermal fluid were assumed $160^{\circ}C$ and $60^{\circ}C$, respectively, based on reservoir temperature of $180^{\circ}C$ calculated from the geothermal gradient of $33^{\circ}C$ in Pohang area. In this temperature range, 0.11 of thermal efficiency of the binary generation cycle is a practical choice. Assuming flow rates of 40 kg/sec, which is possible in current EGS technology, gross power generation capacity is estimated to reach 1.848 MW. Net generation considering auxiliary power including pumping power for geothermal fluid and condensing (cooling) energy of working fluid can be 1.5 MW.

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Heat Transfer Characteristics of High Temperature molten salt storage for Solar Thermal Power Generation (태양열 발전을 위한 고온 축열 물질의 열전달 특성)

  • Aiming, Mao;KIm, Ki-Man;Han, Gui-Young;Seo, Tae-Beom;Kang, Yong-Heack
    • Journal of the Korean Solar Energy Society
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    • v.27 no.3
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    • pp.63-69
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    • 2007
  • The heat transfer characteristics of inorganic salt for high temperature heat storage material of solar power system were examined. The inorganic salts employed in this study was a mixture of $NaNO_3$ and $KNO_3$ and the operating temperature range was determined by measuring the melting temperature with DSC and by measuring the thermal decomposition temperature with TGA. The heat transfer characteristics was qualitatively obtained in terms of temperature profiles of salt in the tanks during the heat storage and heat release process as a function of steam flow rates, steam inlet temperature and the inlet position of steam. The effects of steam flow rates and inlet temperature of steam were experimentally determined and the effect of natural convection was observed due to significant density difference with temperature.

A Study on Thermal and Mechanical Behaviors of Micro Reformer (마이크로 리포머의 열 및 역학적 거동 분석)

  • Hwang W.H.;Jang J.H.;Kil J.H.;Kim S.J.;Lee R.W.;Kim S.H.;Chung K.H.;Oh Y.S.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.235-239
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    • 2005
  • We analyzed the thermal and mechanical behaviors of micro reformer for the purpose of design verifications and modification of micro channels. The reformer designed for hydrogen generation from methanol is essential to PEM(Proton Exchange Membrane) type fuel cell. For the mobile applications, the size and the simplicity would be the most critical issues. We utilized silicon process for micro reformer to obtain the thickness thinner than 2 mm thick. We have used commercial simulation software, IDEAS, to analyze the thermal and mechanical characteristics of micro reformer structure. The heat generation rates of heaters, heat transfer rates, and fluid temperatures are derived from thermal equilibrium relation and these values were used for thermal boundary conditions. We also analyzed the thermal stresses, thermal deformations to examine the possibility of failure.

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Crystal Growth and Second Harmonic Generation of YCa$_4$O$({BO_3})_3$ (YCa$_4$O$({BO_3})_3$ 단결정 성장 및 2차고조파 발생)

  • Yu, Young-Moon;A. Ageyev;Jeong, Suk-Jong
    • Proceedings of the Optical Society of Korea Conference
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    • 2000.08a
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    • pp.88-89
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    • 2000
  • The properties for self-frequency doubling (SFD) is unique phenomena for a small number of special single crystals. It is known that there are serious limitations to vary the concentration of active ions, for example high doping of active ions from 1 to 50 atomic %, in nonlinear materials. Until now, the Nd:YAl$_3$(BO$_3$)$_4$ (YAB) and Nd:(Ce,Gd)Sc$_3$(BO$_3$)$_4$ (CSB) crystals with high doping rates are well studied for the application of SFD purpose. They have much useful SFD properties, but also have big problems in crystal growth. In case of YAB crystal, it can be grown by solution melt method with very low growth rates and easy occurrence of inclusions. In case of CSB crystal, it has optically heterogeneity problems because of disarrangement of ions in huntite structure [1]. These problems make above crystals not so attractive for optical applications. Some popular nonlinear materials, such as LiNbO$_3$(LN), KTiOPO$_4$(KTP), LiB$_3$O$_{5}$ (LBO) crystals, are impossible to substitute by Rare Earth activators because of their crystallo-chemical problems of structure. When we dope active ions with the requisite concentrations for laser generation, it results in decreasing of optical quality of crystals or destroying of acentrosymmetric structure. (omitted)d)

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Anaerobic digestion of food waste to methane at various organic loading rates (OLRs) and hydraulic retention times (HRTs): Thermophilic vs. mesophilic regimes

  • Kumar, Gopalakrishnan;Sivagurunathan, Periyasamy;Park, Jong-Hun;Kim, Sang-Hyoun
    • Environmental Engineering Research
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    • v.21 no.1
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    • pp.69-73
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    • 2016
  • Generation of food waste is a serious issue that needs to be addressed worldwide. Developing suitable treatment methods while generating energy (methane) is a common practice for sustainable treatment of waste. In this study, methane generation by food waste was investigated in mesophilic and thermophilic regimes at various hydraulic retention times (HRTs) and organic loading rates (OLR). In temperature regimes, influent concentrations and HRTs ranged from 30 to 110 g COD/L and 18 to 30 days, respectively, which corresponding to an OLR of 1.0 to $6.1kg\;COD/m^3-d$. Better methane production and organic removal was observed under thermophilic conditions because of the enhanced hydrolysis of complex polymers and microbial activity at higher temperature. The peak methane productivities attained in thermophilic and mesophilic regimes were 1.30 and $0.99m^3/m^3-d$, respectively. The maximum methane yields were achieved at 50 g COD/L and HRT of 24 d in both cases, and the values were 264 and $221m^3/ton$ COD, respectively. The results of this study will facilitate the development of sustainable methane production technologies using food waste as a feedstock.

Quadrature Correlated Superposition Modulation: Practical Perspective of Correlated Superposition Coding

  • Chung, Kyuhyuk
    • International Journal of Internet, Broadcasting and Communication
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    • v.13 no.3
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    • pp.17-24
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    • 2021
  • Recently, a lossless non-orthogonal multiple access (NOMA) implementation without successive interference cancellation (SIC) has been proposed in the literature of NOMA. This lossless non-SIC NOMA was achieved via correlated superposition coding (CSC), in contrast to conventional independent superposition coding (ISC). However, only the achievable data rates for CSC NOMA were investigated. Thus, this paper proposes a practical CSC NOMA scheme under Rayleigh fading channel environments. First, we design the practical CSC NOMA scheme, namely quadrature correlated superposition modulation (CSM) NOMA, without channel coding, i.e., uncoded systems. In addition, we calculate the symbol error rates (SERs) for this quadrature CSM NOMA scheme. Then, simulations demonstrate that for the weak channel gain's user, the SER performance of the proposed quadrature CSM NOMA is shown to be improved greatly, compared to that of the conventional quadrature amplitude modulation (QAM) NOMA, whereas for the strong channel gain's user, the SER performance of the proposed quadrature CSM NOMA degrades a little, compared to that of the conventional QAM NOMA. As a result, the proposed quadrature CSM NOMA scheme could be considered as a practical NOMA scheme for CSC NOMA schemes toward the fifth-generation (5G) and next generation communications.