• Title/Summary/Keyword: Envelope

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Optimization of CANFLEX-RU Fuel Bundle for CANDU-6

  • Lee, Y. O.;C. J. Jeong;K. S. Sim;J. S. Jun;Park, G. S.;Kim, B. G.;Park, J. H.;H. C. Suk
    • Proceedings of the Korean Nuclear Society Conference
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    • 1995.10a
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    • pp.35-40
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    • 1995
  • Considering the higher discharge burnup, lower channel refuelling rate, lower linear element rating(LER), lower coolant void reactivity and axial power shape, CANFLEX-RU fuel bundle is optimized for CANDU-6 by grading the fissile composition in the ring-wise of the bundle and by applying fuel management scheme appropriately. The fissile composition of the fuel bundle is graded as the recovered uranium (0.9 w/o U-235) in the outer and intermediate elements, depleted Uranium (0.2 w/o U-235) in the center element, natural uranium (0.71 w/o U-235) in the inner elements. Enrichment is not required for these fuel. The fissile composition is optimized by lattice calculation and by time-averaged reactor simulation. CANFLEX-RU optimized for CANDU-6 resulted to be the 15% lower channel refuelling rate, acceptable axial power profile and power envelope, 70% higher discharge burnup, 15% lower LER and not increase coolant void reactivity compared with the 37-element natural uranium bundle for CANDU-6.

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Aircraft Digital Fly-By-Wire System Technology Development Trend (항공기 디지털 전자식 비행제어 시스템 기술 개발 동향)

  • Seong-Byeong Chae
    • The Journal of the Korea institute of electronic communication sciences
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    • v.18 no.3
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    • pp.509-520
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    • 2023
  • In this paper, the structure and the characteristics of the Fly-By-Wire system applied to the civil aircraft was described. The development trend of the redundant method of the flight control system, data communication system, control surface actuation system and the control laws implemented by the Fly-By-Wire system of the civil aircraft are discussed. The Fly-By-Wire system was first applied to the fighter and its inherent advantages lead to the advent of the Fly-By-Wire civil aircraft. Recently even the small jet aircraft shows the trend of adopting the Fly-By-Wire system. In the future, most of the aircraft are expected to be the Fly-By-Wire type.

Numerical investigation of the hysteretic response analysis and damage assessment of RC column

  • Abdelmounaim Mechaala;Benazouz Chikh;Hakim Bechtoula;Mohand Ould Ouali;Aghiles Nekmouche
    • Advances in Computational Design
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    • v.8 no.2
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    • pp.97-112
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    • 2023
  • The Finite Element (FE) modeling of Reinforced Concrete (RC) under seismic loading has a sensitive impact in terms of getting good contribution compared to experimental results. Several idealized model types for simulating the nonlinear response have been developed based on the plasticity distribution alone the model. The Continuum Models are the most used category of modeling, to understand the seismic behavior of structural elements in terms of their components, cracking patterns, hysteretic response, and failure mechanisms. However, the material modeling, contact and nonlinear analysis strategy are highly complex due to the joint operation of concrete and steel. This paper presents a numerical simulation of a chosen RC column under monotonic and cyclic loading using the FE Abaqus, to assessthe hysteretic response and failure mechanisms in the RC columns, where the perfect bonding option is used for the contact between concrete and steel. While results of the numerical study under cyclic loading compared to experimental tests might be unsuccessful due to the lack of bond-slip modeling. The monotonic loading shows a good estimation of the envelope response and deformation components. In addition, this work further demonstrates the advantage and efficiency of the damage distributions since the obtained damage distributions fit the expected results.

Multiepoch Optical Images of IRC+10216 Tell about the Central Star and the Adjacent Environment

  • Kim, Hyosun;Lee, Ho-Gyu;Ohyama, Youichi;Kim, Ji Hoon;Scicluna, Peter;Chu, You-Hua;Mauron, Nicolas;Ueta, Toshiya
    • The Bulletin of The Korean Astronomical Society
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    • v.46 no.2
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    • pp.36.1-37
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    • 2021
  • Six images of IRC+10216 taken by the Hubble Space Telescope at three epochs in 2001, 2011, and 2016 are compared in the rest frame of the central carbon star. An accurate astrometry has been achieved with the help of Gaia Data Release 2. The positions of the carbon star in the individual epochs are determined using its known proper motion, defining the rest frame of the star. In 2016, a local brightness peak with compact and red nature is detected at the stellar position. A comparison of the color maps between 2016 and 2011 epochs reveals that the reddest spot moved along with the star, suggesting a possibility of its being the dusty material surrounding the carbon star. Relatively red, ambient region is distributed in an Ω shape and well corresponds to the dusty disk previously suggested based on near-infrared polarization observations. In a larger scale, differential proper motion of multiple ring-like pattern in the rest frame of the star is used to derive the average expansion velocity of transverse wind components, resulting in ~12.5 km s-1 (d/123 pc), where d is the distance to IRC+10216. Three dimensional geometry is implied from its comparison with the line-of-sight wind velocity determined from half-widths of submillimeter emission line profiles of abundant molecules. Uneven temporal variations in brightness for different searchlight beams and anisotropic distribution of extended halo are revisited in the context of the stellar light illumination through a porous envelope with postulated longer-term variations for a period of 10 years.

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Characterization of Novel Amylase-Sensitive, Anti-Listerial Class IId Bacteriocin, Agilicin C7 Produced by Ligilactobacillus agilis C7

  • Jeong Min Yoo;Ji Hoon Song;Robie Vasquez;In-Chan Hwang;Jae Seung Lee;Dae-Kyung Kang
    • Food Science of Animal Resources
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    • v.43 no.4
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    • pp.625-638
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    • 2023
  • Among various biological agents, bacteriocins are important candidates to control Listeria monocytogenes which is a foodborne pathogen. In this study, a novel bacteriocin, named agilicin C7, was isolated from Ligilactobacillus agilis C7 showing inhibitory activity against L. monocytogenes. Agilicin C7 biosynthesis gene was characterized by bioinformatics analyses and heterologously expressed in Escherichia coli for further study. The anti-listeria activity of recombinant agilicin C7 (r-agilicin C7) was lost by proteases and α-amylase, suggesting that agilicin C7 is a glycoprotein. r-Agilicin C7 has wide pH and thermal stability and is also stable in various organic solvents. It destroyed L. monocytogenes by damaging the integrity of the cell envelope. These properties of r-agilicin C7 indicate that agilicin C7 is a novel amylase-sensitive anti-listerial Class IId bacteriocin. Physicochemical stability and inhibitory activity against L. monocytogenes of r-agilicin C7 suggest that it can be applied to control L. monocytogenes in the food industry, including dairy and meat products.

Energy Performance Evaluation Study on the Thermal Bridge Blocking External Insulation System for Green Remodeling (그린 리모델링용 열교 차단 외단열 시스템의 에너지 성능 평가 연구)

  • Kim, Woong-Hoi;Kang, Eun-Ho;Yoon, Jong-Ho
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2021.11a
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    • pp.234-235
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    • 2021
  • We set the representative balcony types of the existed building to two types: unexpanded balcony and extended balcony, and analyze the effect of reducing the cooling and heating energy load when applying remodeling. The scope of the study was limited to balcony walls, including window-wall junctions, and was conducted by comparing cases with and without thermal break insulation structures for a clear conclusion. The study was conducted using the equivalent U-value in each case. The equivalent U-value was calculated by deriving through 2 dimensional steady-state heat transfer analysis of each case balcony envelope. And building energy was calculated using the derived equivalent U-value. According to the calculation results, for unexpanded balconies, the equivalent U-value was reduced by about 80%, and the heating and cooling load was reduced by about 20%. In the case of extended balconies, the equivalent U-value was reduced by about 57% and the resulting heating and cooling load was reduced by about 12%.

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volution of massive stars in Case A binary systems and implications for supernova progenitors

  • Lee, Hunchul;Yoon, Sung-Chul
    • The Bulletin of The Korean Astronomical Society
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    • v.45 no.1
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    • pp.70.4-71
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    • 2020
  • One of the distinctive characteristics of the evolution of binary systems would be mass transfer. Close binary systems experience so-called Case A mass transfer during the main-sequence. We have performed calculations of the evolution of massive Case A (with the initial period 1.5 ~ 4.5 days) binary systems with the initial mass of 10 ~ 20 solar masses and mass ratio 0.5 ~ 0.95 using the MESA code. We find that in some systems, after the first mass transfer, the secondary stars evolve faster than the primary stars and undergo so-called 'reverse' mass transfer. Such phenomena tend to occur in relatively low-mass (initial mass < 16 solar masses) and close (initial period < 3 day) systems. Unless a system enters the common-envelope phase, the primary star would become a single helium star after the secondary star ends its life if the system were unbound by the neutron star kick. We find the various evolutionary implications of the remaining primary stars. In addition to the evolution into the compact single helium star progenitor, there is a possibility that the remaining primary star could evolve into a helium giant star, which could be a promising candidate for Type Ibn supernova progenitor, depending on the core mass. Further, we find that some primary stars satisfy the conditions for the formation of electron-capture supernova progenitor.

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A Study on Dynamic Safety Navigation Envelopes Considering a Ship's Position Uncertainty

  • Pyo-Woong Son;Youngki Kim;Tae Hyun Fang;Kiyeol Seo
    • Journal of Positioning, Navigation, and Timing
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    • v.12 no.3
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    • pp.289-294
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    • 2023
  • As technologies such as cameras, Laser Imaging, Detection, and Ranging (LiDAR), and Global Navigation Satellite Systems (GNSS) become more sophisticated and common, their use in autonomous driving technologies is being explored in various fields. In the maritime area, technologies related to collision avoidance between ships are being developed to evaluate and avoid the risk of collision between ships by setting various scenarios. However, the position of each vessel used in the process of developing collision avoidance technology between vessels uses data obtained through GNSS, and may include a position error of 10 m or more depending on the situation. In this paper, a study on the dynamic safety navigation range including the positional inaccuracy of the ship is conducted. By combining the concept of the protection level obtained using GNSS raw data with a conventional safe navigation range, a safer navigation range can be calculated for dynamic navigation. The calculated range is verified using data obtained while sailing in an actual sea environment.

New Temporal Features for Cardiac Disorder Classification by Heart Sound (심음 기반의 심장질환 분류를 위한 새로운 시간영역 특징)

  • Kwak, Chul;Kwon, Oh-Wook
    • The Journal of the Acoustical Society of Korea
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    • v.29 no.2
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    • pp.133-140
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    • 2010
  • We improve the performance of cardiac disorder classification by adding new temporal features extracted from continuous heart sound signals. We add three kinds of novel temporal features to a conventional feature based on mel-frequency cepstral coefficients (MFCC): Heart sound envelope, murmur probabilities, and murmur amplitude variation. In cardiac disorder classification and detection experiments, we evaluate the contribution of the proposed features to classification accuracy and select proper temporal features using the sequential feature selection method. The selected features are shown to improve classification accuracy significantly and consistently for neural network-based pattern classifiers such as multi-layer perceptron (MLP), support vector machine (SVM), and extreme learning machine (ELM).