• Title/Summary/Keyword: Storage Structure

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Simplified Analysis of Rectangular Liquid Storage Tanks Considering Fluid-Structure Interaction (유체-구조물 상호작용을 고려한 직사각형 액체저장탱크의 단순해석법)

  • Lee, Jin Ho;Cho, Jeong-Rae
    • Journal of the Earthquake Engineering Society of Korea
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    • v.26 no.5
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    • pp.203-209
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    • 2022
  • A simplified method for earthquake response analysis of a rectangular liquid storage tank is proposed with fluid-structure interaction considered. In order to simplify the complex three-dimensional structural behavior of a rectangular liquid storage tank, it is assumed that structural deformation does not occur in the plane parallel to the direction in which the earthquake ground motion is applied but in the plane perpendicular to the direction. The structural deformation is approximated by combining the natural modes of the simple beam and the cantilever beam. The hydrodynamic pressure, the structure's mass and stiffness, and the hydrodynamic pressure's added mass are derived by applying the Rayleigh-Ritz method. The natural frequency, structural deformation, pressure, effective mode mass, and effective mode height of the rectangular liquid storage tank are obtained. The structural displacement, hydrodynamic pressure, base shear, and overturning moment are calculated. The seismic response analysis of an example rectangular liquid storage tank is performed using the proposed simplified approach, and its accuracy is verified by comparing the results with the reference solution by the finite element method. Existing seismic design codes based on the hydrodynamic pressure in rigid liquid storage tanks are observed to produce results with significant errors that cannot be ignored.

Topology optimization of tie-down structure for transportation of metal cask containing spent nuclear fuel

  • Jeong, Gil-Eon;Choi, Woo-Seok;Cho, Sang Soon
    • Nuclear Engineering and Technology
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    • v.53 no.7
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    • pp.2268-2276
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    • 2021
  • Spent nuclear fuel, which can degrade during long-term storage, must be transported intact in normal transport conditions. In this regard, many studies, including those involving Multi-Modal Transportation Test (MMTT) campaigns, have been conducted. In order to transport the spent fuel safely, a tie-down structure for supporting and transporting a cask containing the spent fuel is essential. To ensure its structural integrity, a method for finding an optimum conceptual design for the tie-down structure is presented. An optimized transportation test model of a tie-down structure for the KORAD-21 metal cask is derived based on the proposed optimization approach, and the transportation test model is manufactured by redesigning the optimized model to enable its producibility. The topology optimization approach presented in this paper can be used to obtain optimum conceptual designs of tie-down structures developed in the future.

RDB Schema Model of XML Document for Storage Capacity and Searching Efficiency (저장 공간과 검색 효율을 위한 XML 문서의 RDB 스키마 모델)

  • Kim Jeong-Hee;Kwak Ho-Young;Kwon Hoon
    • The Journal of the Korea Contents Association
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    • v.6 no.4
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    • pp.19-28
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    • 2006
  • XML instances for purpose of information exchange are normally stored in the legacy relational database. Therefore, integrations with relational database are required for effective XML applications. To support these requirements, virtual decomposition storage or decomposition storage methods which save separates structures of instances to relational database have researched. However, these storage methods contain different information of schema structure and layers which has caused difficulties to process query during search operation as well as increased overheads due to duplicate savings for separate storages. Therefore, in this research, additional field of 'Eltype' has introduced to previous database schema structure to instance and schema structure, provide consistent level information and propose storage structure to map each field to schema field of relational database. As results, XML instance and structures can be stored together to minimize overheads and required storage-space. Also, synchronized storage layer structure provides easier processing of search query.

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Effect of surface treatments on Single-walled Carbon nanotubes(SWNTs) for Hydrogen storage (수소저장용 단일벽 탄소나노튜브의 표면처리 효과)

  • Lee, Young-Seak;Cho, Se-Ho;Park, Il-Nam
    • Transactions of the Korean hydrogen and new energy society
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    • v.16 no.4
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    • pp.343-349
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    • 2005
  • In this study, We had surface-treated single-walled carbon nanotubes (SWNTs) for improving hydrogen storage capacity. The SWNTs were treated by heat treatment, acid treatment and fluorinated at various temperatures. The SWNTs were characterized by Raman spectroscopy and TEM and estimated hydrogen storage capacities at 303K. As shown Raman spectra and TEM images, the structure of fluorinated SWNTs were stable at 423K but changed to the MWNTs-like structure or onion structure over 523K. Hydrogen storage capacity of SWNTs fluorinated at 423K was remarkably increased 2.6 times than that of pristine SWNTs. For SWNTs fluorinated at 573K, the amount of hydrogen adsorbed wasn't increased compared with SWNTs fluorinated at 423K. Therefore, high hydrogen storage capacity of SWNTs could be archived by fluorinated condition at 423K, which was not changed SWNT structure.

Review of seismic studies of liquid storage tanks

  • Zhao, Ming;Zhou, Junwen
    • Structural Engineering and Mechanics
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    • v.65 no.5
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    • pp.557-572
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    • 2018
  • The academic research works about liquid storage tanks are reviewed for the purpose of providing valuable reference to the engineering practice on their aseismic design. A summary of the performance of tanks during past earthquakes is described in this paper. Next, the seismic response of tanks under unidirectional earthquake is reported, supplemented with the dynamic response under multidirectional motions. Then, researches on the influence of soil-structure interaction are brought out to help modify the seismic design approach of tanks in different areas with variable properties of soils. Afterwards, base isolation systems are reported to demonstrate their effectiveness for the earthquake-resistant design of liquid storage tanks. Further, researches about the liquid-structure interaction are reviewed with description of simplified models and numerical analytical methods, some of which consider the elastic effect of tank walls. Moreover, the liquid sloshing phenomenon on the hydrodynamic behaviors of tanks is presented by various algorithms including grid-based and meshfree method. And then the impact of baffles in changing the dynamic characteristics of the liquid-structure system is raised, which shows the energy dissipation by the vortex motion of liquid. In addition, uplifting effect is given to enhance the understanding on the capacity of unanchored tanks and some assessment of their development. At last, the concluding remarks and the aspects of extended research in the field of liquid storage tanks under seismic loads are provided, emphasizing the thermal stress analysis, the replaceable system for base isolation, the liquid-solid interaction and dynamic responses with stochastic excitations.

Temporal Data Migration Strategies by Time Granularity and LST-GET (시간단위와 LST-GET에 의한 시간지원 데이터의 이동 기법)

  • 윤홍원;김경석
    • Journal of Korea Multimedia Society
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    • v.2 no.1
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    • pp.9-21
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    • 1999
  • This paper presents the time-segmented storage structure in order to increment search performance and the two data migration strategies: migration by Time Granularity and migration by LST-GET. In the migration strategy by Time Granularity, we describe how to assign entity version to the past, current segment, and future segments. We also describe searching and moving processes for data validity at a granularity level. In the migration strategy by LST-GET, we describe how to computer the value of dividing criterion. We simulate the search performance of the proposed segmented storage structure in comparison with the conventional storage structure in comparison with the conventional storage structure in relational database system. Finally, extensive simulation studies are performed in order to compare the search performance of the migration strategies with the time-segmented storage structure.

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Seismic vulnerability of sliding isolation concrete rectangular liquid storage tanks

  • Cheng, Xuansheng;Yin, Siyuan;Chen, Wenjun;Jing, Wei
    • Structural Engineering and Mechanics
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    • v.84 no.4
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    • pp.503-515
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    • 2022
  • Based on the sliding isolation concrete LSS (liquid-storage structure), the specific seismic vulnerability is analyzed according to the general failure mode. In this study, 12 seismic inputs with different characteristics are used, and their acceleration peak values are modulated. By inputting these waves to the sliding isolation concrete storage structure, the finite-element models of different concrete rectangular LSSs are obtained and analyzed, and the failure probabilities are obtained according to the IDA (incremental dynamic analysis) curves of the structure. The results show that when the seismic acceleration peak value gradually increases from 0.1 g to 1.0 g, the failure probability of LSS gradually increases with the increase in friction coefficient. However, the failure probability of a sliding isolation LSS is less than 100% and far less than the failure probability of a non-isolated rectangular LSS, which shows that an isolated liquid storage structure continues working under a big earthquake. Thus, the sliding isolation for the concrete LSS has a significant damping effect.

Data structures and the performance improvement of the minimum degree ordering method (최소차수순서화의 자료구조개선과 효율화에 관한 연구)

  • 모정훈;박순달
    • Korean Management Science Review
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    • v.12 no.2
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    • pp.31-42
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    • 1995
  • The ordering method is used to reduce the fill-ins in interior point methods. In ordering, the data structure plays an important role. In this paper, first, we compare the efficiency and the memory storage requirement of the quotient graph structure and the clique storage. Next, we propose a method of reducing the number of cliques and a data structure for clique storage. Finally, we apply a method of merging rows and absorbing cliques and show the experimental results.

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An Index Structure for Main-memory Storage Systems using The Level Pre-fetching

  • Lee, Seok-Jae;Yoon, Jong-Hyun;Song, Seok-Il;Yoo, Jae-Soo
    • International Journal of Contents
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    • v.3 no.1
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    • pp.19-23
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    • 2007
  • Recently, several main-memory index structures have been proposed to reduce the impact of secondary cache misses. In mainmemory storage systems, secondary cache misses have a substantial effect on the performance of index structures. However, recent studies still stiffer from secondary cache misses when visiting each level of index tree. In this paper, we propose a new index structure that minimizes the total amount of cache miss latency. The proposed index structure prefetched grandchildren of a current node. The basic structure of the proposed index structure is based on that of the CSB+-Tree, which uses the concept of a node group to increase fan-out. However, the insert algorithm of the proposed index structure significantly reduces the cost of a split. The superiority of our algorithm is shown through performance evaluation.

Seismic Response of Base-Isolated Liquid Storage Tanks Considering Liquid-Structure-Soil Interaction (유체-구조물-지반 상호작용을 고려한 면진된 유체저장탱크의 3차원 지진응답)

  • 조성용;김문겸;임윤묵
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2002.09a
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    • pp.98-105
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    • 2002
  • The effects of the base-isolation system and elastic soil foundation on the behavior of a liquid storage tank are studied. To evaluate the seismic response of liquid storage tank accurately, the coupled dynamic system considering base isolation and soil interaction problem is formulated in time domain. Results show that the base isolation system reduces effectively the radial displacements, base shears, overturning moments, axial resultant stresses and the hydrodynamic pressure by providing flexibility and energy dissipation capability. Base Isolation may, however, increase the relative liquid sloshing amplitude due to the effect of liquid-structure interaction and cause excessive large relative displacements between structure and foundation. In addition to base-isolator, the dynamic behavior of liquid storage tank is related to the flexibility of base foundation, so the analysis of soil-structure interaction s achieved.

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