• Title/Summary/Keyword: Concentrated mass

검색결과 361건 처리시간 0.033초

유체-구조 상호작용을 적용한 튜브다발의 유체탄성불안정성 과도적 전산해석 (Multi-Physics Simulations of Fluidelastic Instability for Tube Bundles in Cross-Flow)

  • 이민형;김용찬
    • 대한기계학회논문집B
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    • 제28권2호
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    • pp.174-180
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    • 2004
  • Failure of tube bundles due to excessive flow-induced vibrations continues to affect the performance of nuclear power plant Early experimental studies concentrated on rigid structures and later investigators dealt with elastic structures because of their importance in many engineering fields. On the other hand, much less numerical work has been carried out, because of the numerical complexity associated with the problem. Conventional approaches usually decoupled the flow solution from the structural problem. The present numerical study proposes the methodology in analyzing the fluidelastic instability occurring in tube bundles by coupling the Computational fluid Dynamics (C%) with the tube equation of motions. The motion of the structures is modeled by a spring-damper-mass system that allows transnational motion in two directions (a two-degree-of-freedom system). The fluid motion and the cylinder response are solved in an iterative way, so that the interaction between the fluid and the structure can be accounted for property. The aim of the present work is to predict the fluidelstic instability of tube bundles and the associated phenomena, such as the response of the cylinder, the unsteady lift and drag on the cylinder, the vortex shedding frequency.

Effect of structure configurations and wind characteristics on the design of solar concentrator support structure under dynamic wind action

  • Kaabia, Bassem;Langlois, Sebastien;Maheux, Sebastien
    • Wind and Structures
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    • 제27권1호
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    • pp.41-57
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    • 2018
  • Concentrated Solar Photovoltaic (CPV) is a promising alternative to conventional solar structures. These solar tracking structures need to be optimized to be competitive against other types of energy production. In particular, the selection of the structural parameters needs to be optimized with regards to the dynamic wind response. This study aims to evaluate the effect of the main structural parameters, as selected in the preliminary design phase, on the wind response and then on the weight of the steel support structure. A parametric study has been performed where parameters influencing dynamic wind response are varied. The study is performed using a semi-deterministic time-domain wind analysis method. Unsteady aerodynamic model is applied for the shape of the CPV structure collector at different configurations in conjunction with a consistent mass-spring-damper model with the corresponding degrees of freedom to describe the dynamic response of the system. It is shown that, unlike the static response analysis, the variation of the peak wind response with many structural parameters is highly nonlinear because of the dynamic wind action. A steel structural optimization process reveals that close attention to structural and site wind parameters could lead to optimal design of CPV steel support structure.

유체와 온도 조절을 이용한 생화학 물질 반응용 마이크로칩의 개발 (BEAD BASED CHEMICAL REACTION SYSTEM USING TEMPERATURE AND FLUID CONTROL FOR CANCER DETECTION)

  • 김민수;이보람;윤효진;김병기;이윤식;김용권
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2008년도 제39회 하계학술대회
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    • pp.1466-1467
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    • 2008
  • We describe here a novel micro total analysis system for the purification and identification of the affinity-captured proteins. Also we demonstrated the mass analysis of the Carcinoembrionic antigen (CEA) and Alpha femtoprotein which were chosen as the target cancer marker. For MALDI-TOF analyses, the proteins should to be separated from a protein mixture and be concentrated when needed. This procedure usually takes a long time even before protease-digested samples are to be obtained from them. Here, we describe integrated and efficient micro chip for protein purification and digestion for MALDI-TOF analyses. At first, disease protein is purified by passing the micro chamber from a protein mixture or human whole serum and released from the micro affinity beads by thermal heating. Purified protein is then transfer to the hole for trypsin digestion. The final sample is analyzed by MALDI-TOF. All the processes could be finished successfully within one hour, which renders MALDI-TOF analyses of a target protein quite simple.

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마운트 시스템을 갖는 유연 로터-베어링 시스템의 기초전달 충격 과도응답 해석을 위한 유한요소 모델링 (FE Modeling for the Transient Response Analysis of a Flexible Rotor-bearing System with Mount System to Base Shock Excitation)

  • 이안성;김병옥
    • 한국소음진동공학회논문집
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    • 제17권12호
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    • pp.1208-1216
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    • 2007
  • Turbomachinery such as turbines, pumps and compressors, which are installed in transportation systems, including aircrafts, ships, and space vehicles, etc., often perform crucial missions and are exposed to potential dangerous impact environments such as base-transferred shock forces. To protect turbomachinery from excessive shock forces, it may be needed to accurately analyze transient responses of their rotors, considering the dynamics of mount designs to be applied. In this study a generalized FE transient response analysis model, introducing relative displacements, is proposed to accurately predict transient responses of a flexible rotor-bearing system with mount systems to base-transferred shock forces. In the transient analyses the state-space Newmark method of a direct time integration scheme is utilized, which is based on the average velocity concept. Results show that for the identical mount systems considered, the proposed FE-based detailed flexible rotor model yields more reduced transient vibration responses to the same shocks than a conventional simple model, obtained by treating a rotor as concentrated lumped mass, equivalent spring and a damper or Jeffcott rotor model. Hence, in order to design a rotor-bearing system with a more compact light-weighted mount system, preparing against any potential excessive shock, the proposed FE transient response analysis model herein is recommended.

Isolation of Flavonoids from Processed Aconiti Tuber

  • Lyu, Ha-Na;Kwak, Ho-Young;Lee, Dae-Young;Kim, Kyong-Tai;Kim, Se-Young;Baek, Nam-In
    • Journal of Applied Biological Chemistry
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    • 제51권4호
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    • pp.165-168
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    • 2008
  • A processed Aconiti tuber (Korean name, Kyeong-Po Buja) was extracted with 80% aqueous EtOH, and the concentrated extract was partitioned with EtOAc and water ($H_2O$). From the EtOAc fraction, two flavonoids were isolated through repeated silica gel column chromatographies. From the result of physico-chemical data including NMR, mass spectrometry and IR, the chemical structures of the compounds were determined to be liquiritin (1) and liquiritigenin (2). This is the first study to isolate flavonoids (1) and (2) from the processed Aconiti tuber.

커피박에 의한 구름버섯 균사체의 생장 촉진 (Acceleration of the Mycelial Growth of Trametes veriscolor by Spent Coffee Ground)

  • 이민구;신동일;박희성
    • 한국균학회지
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    • 제40권4호
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    • pp.292-295
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    • 2012
  • 구름버섯은 온대지역에서 흔히 발견되는 목재 부후균으로서 중요한 약용버섯의 일종이다. 본 연구에서는 커피박, 과립커피 및 과립 디카페인 커피의 구름버섯 균사체 생장에 미치는 영향을 조사하였다. 그 결과, 커피박은 10% 농도에서까지 그리고 과립커피의 경우 1% 미만에서 균사체 생육을 촉진시키는 것으로 확인되었다. 1% 커피박의 경우 무처리에 비해 10배 정도의 건조중량 증가가 측정됨으로써 구름균사체의 생육촉진제로서의 커피 효능을 확인할 수 있었다. 또한 커피는 균사체의 페놀화합물 및 항산화 효능 증대를 위한 유용 물질로 판단되었다.

공기보조 분사기와 고압 선회식 분사기의 특성 비교 - Part II: 미시적 분무특성 (Comparison of Overall Characteristics between an Air-Assisted Fuel Injector and a High-Pressure Swirl Injector- Part II: Microscopic Spray Characteristics)

  • 장창수;최상민
    • 한국자동차공학회논문집
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    • 제8권5호
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    • pp.28-35
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    • 2000
  • As a second part of the comparison study, microscopic features of an air-assisted fuel injector(AAFI) and a high-pressure swirl injector (HPSI) were characterized. They consist of the internal spray structure in terms of fuel mass and drop diameter, the overall atomization performance with respect to operating parameters and the drop size distribution. Large droplets are concentrated in around the head part of a spray field of the HPSI, while in the case of the AAFI, they were distributed in the tail part. Although the AAFI showed the better atomization performance, the feasible ranges of operating parameters such as injection and ambient pressure were found to be wider in the HPSI. Drop size distribution of the AAFI sprays was more dispersed than that of the HPSI. Drop size distribution of the AAFI sprays was more dispersed than that of the HPSI. However, at the well-atomized condition, it appeared to be very uniform.

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Electrostatic Charging Measurement and PVC Separation of Triboeletrostatically Charged Plastic Particles using a Fluidized Bed Tribocharger

  • Shin, Jin-Hyouk;Lee, Jae-Keun
    • 한국분무공학회지
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    • 제7권2호
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    • pp.7-15
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    • 2002
  • A particle flow visualization, electrostatic charging measurement and separation of triboelectrically charged particles in the external electric field by a fluidized bed tribocharger are conducted for the removal of PVC particles from mixed waste plastics. The laboratory-scale triboelectrostatic separation system consists of the fluidized bed tribocharger, a separation chamber, a collection chamber and a controller. PVC and PET particles can be imparted negative and positive surface charges respectively due to the difference of triboelectric charging series between particles and particles in the fluidized bed tribocharger, and can be separated by passing them through an external electric field. To visualize these charged particles, He-Ne laser is used with cylindrical lenses to generate a sheet beam. In the charging measurement, the particle motion analysis system (PMAS), capable of determining particle velocity and diameter. is used to non-intrusively measure particle behavior in high strength electric field. The average charge-to-mass ratios of PVC and PET particles are $1.4\;and\;1.2{\mu}C/kg$, respectively. The highly concentrated PVC (91.9%) can be recovered with a yield of about 96.1% from the mixture of PVC and PET materials for a single-stage processing. The triboelectrostatic separation system using the fluidized tribocharger shows the potential to be an effective method for removing PVC from mixed plastics for waste plastic recycling.

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해양오염 방제체제의 선진화 방안 (Strategies for Advancement of response management system on marine pollution)

  • 김대원
    • 한국해양환경ㆍ에너지학회지
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    • 제3권1호
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    • pp.3-24
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    • 2000
  • 한국연안도 해상교통량 증가, 선원자질저하 및 노후선박증가로 수만톤을 초과하는 기름유출사고의 위험이 상존하고 있다. 이러한 대형 오염사고 발생에 효과적으로 대응하기 위한 선진 방제체제의 구축방안은 다음과 같다. 1. 범국가적 차원의 국가긴급계획을 효율적으로 실행하기 위한 과학적인 지역긴급계획의 수립 2. 2만톤의 축가방제능력 조기 확보 3. 해양오염방제 전문교육ㆍ훈련의 강화 4. NOWPAP사업 추진등 인접국가간 방제협력체제의 구축 21세기 방제정책은 선진 방제체제를 조기에 구축하여 방제작업의 과학적ㆍ전문화ㆍ국제화를 동한 실행적 방제능력 향상에 주력하여야 할 것이다.

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고추 Oleoresin 의 가열조리중 Carotenoid 색소의 변화 (Changes in Carotenoid Pigments of Oleoresin Red Pepper during Cooking)

  • 최옥수;하봉석
    • 한국식품영양과학회지
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    • 제23권2호
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    • pp.225-231
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    • 1994
  • As the way of mass process of red pepper, extraction of oleoresin, which is labile during distribtuion and long-term storage, is alternative way to minimize markdown of red pepper quality. Changes of carotenoid pigments in modified oleoresin during cooking at high temperature were investigated. Dried red peperwas milled to 100 mesh of size particle and oily compounds were extracted by reduced pressure steam distillation. The rest part was reetracted and concentrated. The extracts were combined . The same volume of water and 4 % of polyglycerol condensed ricinoleate (PGDR) were added to the combined extract, and emulsified to make oleroesin. Capsanthin among dried red pepper, was the most abundant carotenoid (97.80mg%) followed by $\beta$ -cartoene, cryptoxanghin ,violaxanthin, crypotocapsin, and capsorubin. Oleoresin is acquiesce in the same order of raw red pepper. Transmittal of color components from raw red pepper to oleroresin was over 85% in cryptoxanthin, crytocapsin, and $\beta$ -carotene, over 70% in capsolutein and hydroxycapsolutein, and under 50% in antheraxanthin and mutatoxanthi Crytocapsin cryptoxanthin, an capsorubin in oleoresin red pepper were remained 72.1, 51.8 and 25.25, respectively, after cooking for 5hours at10$0^{\circ}C$. Color compounds were unsteady by cooking , About 90% of color compounds were destroyed by 3 hours cooking at 15$0^{\circ}C$. But, they were more thermostable under nitrogen circumstance than air one.

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