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A Study on the Thermal Characteristics of Waste Organic Sludges Generated from the Industrial Complex -Paper and Beverage Manufacturing Industries- (산업단지에서 배출되는 폐 유기성 슬러지의 열적 특성 -제지업 및 음식료업을 중심으로-)

  • Shon, Byung-Hyun;Lee, Joo-Ho;Jung, Moon-Hun;Kim, Min-Choul;Ko, Ju-Hyun;Park, Hung-Suck;Lee, Gang-Woo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.9 no.5
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    • pp.1359-1367
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    • 2008
  • We analyzed the physical and chemical properties such as proximate analysis, ultimate analysis, heating values, thermogravimetric analysis, and combustion test for the organic sludges generated from paper and beverage manufacturing industries in the industrial complex. The average water and combustible content of the organic sludges from paper and beverage manufacturing industries were 66.07% and 14.67%, 54.98% and 26.77%, respectively. From the ultimate analysis of the organic sludges, C, H, O, N, and S compositions were 21.75%, 3.42%, 32.70%, 0.63%, and 0.30%, respectively. For beverage manufacturing industries, C, H, O, N, and S compositions were 39.88%, 4.28%, 23.20%. 2.65%, and 0.35%, respectively. According to the results of investigating the lower heating values by Dulong's equation, 1 sludge(T company) was on the range of over 2,000 kcal/kg. This sludge could be directly applied to industries which try to use the energy by direct incineration. From the TGA test, the minimum combustion temperature of A company's sludge was about $700^{\circ}C$ for direct use for energy and that of 3 sludges(C, I, and T company) were at least over $800^{\circ}C$.

CNN Based Spectrum Sensing Technique for Cognitive Radio Communications (인지 무선 통신을 위한 합성곱 신경망 기반 스펙트럼 센싱 기법)

  • Jung, Tae-Yun;Lee, Eui-Soo;Kim, Do-Kyoung;Oh, Ji-Myung;Noh, Woo-Young;Jeong, Eui-Rim
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.24 no.2
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    • pp.276-284
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    • 2020
  • This paper proposes a new convolutional neural network (CNN) based spectrum sensing technique for cognitive radio communications. The proposed technique determines the existence of the primary user (PU) by using energy detection without any prior knowledge of the PU's signal. In the proposed method, the received signal is high-rate sampled to sense the entire spectrum bands of interest. After that, fast Fourier transform (FFT) of the signal converts the time domain signal to frequency domain spectrum and by stacking those consecutive spectrums, a 2 dimensional signal is made. The 2 dimensional signal is cut by the sensing channel bandwidth and inputted to the CNN. The CNN determines the existence of the primary user. Since there are only two states (existence or non-existence), binary classification CNN is used. The performance of the proposed method is examined through computer simulation and indoor experiment. According to the results, the proposed method outperforms the conventional threshold-based method by over 2 dB.

Energy Efficiency Evaluation of IT based Ship Energy Saving System-(1) : Ship Handling Simulator Test Results (IT 기반의 선박에너지절감시스템 성능평가 방법-(1) : 육상시험 수행 결과)

  • Yoo, Yun-Ja
    • Journal of Navigation and Port Research
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    • v.39 no.6
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    • pp.465-472
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    • 2015
  • SEEMP (Ship Energy Efficiency Management Plan) guidelines for a ship's GHG reduction include a machinery modification of hull, an installation of energy efficiency enhanced attachment in hardware methods. It is also possible to bring a ship energy efficiency improvement by fuel-efficient operations or in other software methods. Hardware modification or installation on ship can bring financial burdens to a ship company compared to its improvement expectation. On the other hand, Software based energy-saving technology can be applicable on various ship types, and it is also expected high efficiency of ship energy use compared to hardware based technology in perspective of the investment costs and efficiency. In this paper, it is described that the ship handling simulator based evaluation was carried out using representative ship model of bulk, container and VLCC. Simulation environments were separated into 6 conditions according to the sea-state and weather condition, and the operation results were compared with those before and after energy saving system applied The container ship showed the largest FOC save rate after energy saving system applied although the others also showed energy save rate after using the system.

Design and Performance Test of Locking Curved-Nut (풀림방지 Curved-Nut 설계 및 성능 시험)

  • Cha, Min Cheol;Kang, Ho Sung;Kim, Do Yeop;Lee, Suk Yong;Jeong, Hui Jong;Lee, Eung Suk
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.41 no.3
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    • pp.199-204
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    • 2017
  • Many types of locking nut are commercializing in the various industries where has heavy vibration. Because nut's loosing causes a serious accident. But the most locking nuts are too expensive as the complicate manufacturing process. In this study, we design the new type of locking nut, "Curved-Nut" that is relatively simple making process. We study a relation between the elastic energy and the nut loosing mechanism. So it is analysed, the elastic energy of Curved-Nut comparing with the locking test. The Curved-Nut was manufactured on the commercial nut using a milling tool with horizontal cutting, one or two time under the nut. As the result, the more elastic energy the more prevent the loosing of the nut. We verified the performance of the loosing nut using the vibration testing equipment (NAS3350).

Analysis of the criticality of the shipping cask(KSC-7) (KSC-7 사용후핵연료 수송용기 핵임계해석)

  • Yoon, Jung-Hyun;Choi, Jong-Rak;Kwak, Eun-Ho;Lee, Heung-Young;Chung, Sung-Whan
    • Journal of Radiation Protection and Research
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    • v.18 no.2
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    • pp.47-59
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    • 1993
  • The criticality of the shipping cask(KSC-7) for transportion of 7PWR spent fuel assemblies has been calculated and analysised on the basis of neutron transport theory. For criticality analysis, effects of the rod pitches, the fixed neutron absorbers(borated sus+boral) were considered. The effective multiplication factor has been calculated by KENO-Va, Mote Carlo method computer code, with the HANSEN-ROACH 16 group cross section set, which was made for personal computer system. The criticality for the KSC-7 cask was calculated in terms of the fresh fuel which was conservative for the aspects of nuclear critility. From the results of criticality analysis, the calculated Keff is proved to be lower than subcritical limit during normal transportation and under hypothetical accident condition. The maximum calculated criticalities of the KSC-7 were lower the safety criticality limit 1.0 recommended by US 10CFR71 both under normal and hypothetical accident condition. Also, to verify the KSC-7 criticality calculation results by using KENO-Va, it was carried out benchmark calculation with experimental data of B & W(Bobcock and Wilcox) company. From the 3s series of calculation of the KSC-7 cask and benchmark calculation, the cask was safely designed in nuclear criticality, respectively.

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Research on the Action Strategies of Plant Facility Industries for Global Shale Gas Development. -A Case of Casting Valve Industry- (글로벌 셰일가스 개발에 따른 플랜트 설비 산업계의 대응 전략 연구 -주조 밸브 산업 중심으로-)

  • Kim, Cheol;Leem, Choon Seong
    • Journal of Convergence for Information Technology
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    • v.8 no.6
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    • pp.389-397
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    • 2018
  • Recently, Global Shale gas development has expanded, increasing shale gas production has transformed the energy market.As a result of the reduction of energy facilities, in order to overcome the management deterioration of domestic casting valve industry and enter the enlarged shale gas plant, tried to confirm the SWOT factor through the second questionnaire based on the questionnaire survey of related industry experts and previous studies. As a strength-strategy, presented three factors besides collaboration with domestic companies, suggested four factors including product development specialized in shale gas plant as a weakness complement. Thesis offer to scholarly-Practical implications, Internal-external environmental factors, strategization for entering New energy market. thesis offer to scholarly, Practical implications, environmental factors, strategization for entering New energy market. After, analyze a important of research strategy, would like to study the impact on the company according to the ranking of importance.

Analysis between Computer Simulation and Real-car Crash Test of Energy Absorption Facilities for Various Road Environments (다양한 환경에 적용 가능한 충격흡수시설의 시뮬레이션 분석 및 실물충돌시험 결과 분석)

  • No, Min Hyung;Park, Jea Hong;Seo, Chang Won;Sung, Jung Gon;Yun, Duk Geun
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.42 no.3
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    • pp.399-407
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    • 2022
  • Energy absorption facilities installed on roads should follow the performance standards of the real-car crash test of 'Installation and Maintenance Guidelines for Roadside Safety Facilities'. However, due to different installation conditions, such as differing structure widths on roads, some energy absorption facilities do not provide adequate performance. In order to apply varied environments on roads, an energy absorption structure was designed in this study with 150 mm height and four layers of W-shape guardrail at 200 mm intervals, and the performance was verified using LS-DYNA computer simulation. Through a real-car crash test, the performance of the facility designed by LS-DYNA was tested and was found to meet the performance of the CC2 category for crash cushions. The conclusion of the comparison demonstrates that the simulation and the real-car crash tests are both significant.

Independence test and distribution inference for log returns of KOSPI energy companies (코스피 에너지 기업들의 로그수익률에 대한 독립성 검정과 분포 추론 연구)

  • Yujin Lee;Soyeon Park;Eunju Hwang
    • The Korean Journal of Applied Statistics
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    • v.37 no.6
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    • pp.817-834
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    • 2024
  • Energy industry is an essential factor not only in the lives of individuals but also in the national development of all fields. This paper aims to study the independence test and distribution of log returns for top 6 energy companies in KOSPI. A cross-analysis on combinations of the six energy companies is conducted for the independence test. The return distributions are explored by adopting compressed exponential distribution function, which is a role of bridge between the normal and exponential distributions. Optimal compressed parameters of the return distributions are determined by minimizing the mean square difference between the empirical density function and compressed exponential function. To access a refinement of the distribution, asymmetry or skewness are tested via the Wilcoxon signed rank test, and the asymmetric compressed exponential distributions are inferred on two sides of negative and nonnegative returns, respectively. The results of this work can help to provide an explicit analysis along with probabilistic information about the returns.

Prediction and analysis of structural noise of a box girder using hybrid FE-SEA method

  • Luo, Wen-jun;Zhang, Zi-zheng;Wu, Bao-you;Xu, Chang-jie;Yang, Peng-qi
    • Structural Engineering and Mechanics
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    • v.75 no.4
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    • pp.507-518
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    • 2020
  • With the rapid development of rail transit, rail transit noise needs to be paid more and more attention. In order to accurately and effectively analyze the characteristics of low-frequency noise, a prediction model of vibration of box girder was established based on the hybrid FE-SEA method. When the train speed is 140 km/h, 200 km/h and 250 km/h, the vibration and noise of the box girder induced by the vertical wheel-rail interaction in the frequency range of 20-500 Hz are analyzed. Detailed analysis of the energy level, sound pressure contribution, modal analysis and vibration loss power of each slab at the operating speed of 140 km /h. The results show that: (1) When the train runs at a speed of 140km/h, the roof contributes more to the sound pressure at the far sound field point. Analyzing the frequency range from 20 to 500 Hz: The top plate plays a very important role in controlling sound pressure, contributing up to 70% of the sound pressure at peak frequencies. (2) When the train is traveling at various speeds, the maximum amplitude of structural vibration and noise generated by the viaduct occurs at 50 Hz. The vibration acceleration of the box beam at the far field point and near field point is mainly concentrated in the frequency range of 31.5-100 Hz, which is consistent with the dominant frequency band of wheel-rail force. Therefore, the main frequency of reducing the vibration and noise of the box beam is 31.5-100 Hz. (3) The vibration energy level and sound pressure level of the box bridge at different speeds are basically the same. The laws of vibration energy and sound pressure follow the rules below: web

Determination of Optimum Batch Size and Fuel Enrichment for OPR1000 NPP Based on Nuclear Fuel Cycle Cost Analysis (OPR1000 발전소의 핵연료 주기비분석을 통한 최적 배취 크기와 핵연료 농축도 결정)

  • Cho, Sung Ju;Hah, Chang Joo
    • Journal of Energy Engineering
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    • v.23 no.4
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    • pp.256-262
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    • 2014
  • Cycle length of domestic nuclear power plants is determined by the demand-supply plan of utility company. The target cycle length is achieved by adjusting the number of feed fuel assembly and fuel enrichment. Traditionally, utility company first select the number of feed fuel assembly and then find out the fuel enrichment to achieve the special cycle length. But it is difficult to find out if this method is most economical than any other combinations of the enrichment and batch size satisfying the same cycle length. In this paper, core depletion calculation is performed to find out the optimum combination of the enrichment and batch size for given target cycle length in terms of fuel cycle cost using commercial core design code; CASMO/MASTER code. To minimize the uncertainty resulting from transition core analysis, levelized fuel cycle cost analysis was applied to the equilibrium cycle core in order to determine the optimum combination. The sensitivity study of discount rate was also carried out to analyze the levelized fuel cycle cost applicable to countries with different discount rates. From the levelized fuel cycle cost analysis results, the combination with smaller batch size and higher fuel enrichment becomes more economical as the discount rate becomes lower. On the other hand, the combination with higher batch size and lower fuel enrichment becomes more economical as the discount rate becomes higher.