• 제목/요약/키워드: composite power

검색결과 1,092건 처리시간 0.026초

근대 공공청사 실내공간의 표현성에 관한 연구 (A Study on Characteristic of the Modern Government Office)

  • 이근혜;오인욱
    • 한국실내디자인학회:학술대회논문집
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    • 한국실내디자인학회 2007년도 춘계학술대회 논문집
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    • pp.264-269
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    • 2007
  • Modern architecture does a role in terms of connecting traditional and current architecture. In the same time, Which is important part of korean architecture history because of introduction of western architecture. Accordingly, At this meaninglessly going out and leaving of modern architecture, the purpose of this study is systematic researching of the modern Government Office interior. I progressed this study to research into the period context at construction of the modern Government Office and tendency of architecture and interior at that time. And then understand interior space organization of it. The early modern Government Office adopted Neo-Baroque style from tendency of that time. Also, showed composite order which is mixed in the Greek temple, the Renaissance and the classic style representing the power. But, after late 1920 It adopted Modern Style. This characteristic is different from current composit order, which is comprehended by our. In order to understand aesthetic value of current straight interior space, It have to be interacted the present and past. But It's averted because it was made in the period of Japanese imperialism. Therefore, We should explore history of interior design that is endowed with sociality and historicity between modern and future interior space as well as current.

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Thermal buckling of functionally graded sandwich plates using a new hyperbolic shear displacement model

  • Kettaf, Fatima Zohra;Houari, Mohammed Sid Ahmed;Benguediab, Mohamed;Tounsi, Abdelouahed
    • Steel and Composite Structures
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    • 제15권4호
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    • pp.399-423
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    • 2013
  • In the present study, the thermal buckling behavior of functionally graded sandwich plates is studied using a new hyperbolic displacement model. Unlike any other theory, the theory is variationally consistent and gives four governing equations. Number of unknown functions involved in displacement field is only four, as against five in case of other shear deformation theories. This present model takes into account the parabolic distribution of transverse shear stresses and satisfies the condition of zero shear stresses on the top and bottom surfaces without using shear correction factor. Material properties and thermal expansion coefficient of the sandwich plate faces are assumed to be graded in the thickness direction according to a simple power-law distribution in terms of the volume fractions of the constituents. The core layer is still homogeneous and made of an isotropic material. The thermal loads are assumed as uniform, linear and non-linear temperature rises across the thickness direction. The results reveal that the volume fraction index, loading type and functionally graded layers thickness have significant influence on the thermal buckling of functionally graded sandwich plates.

Thermal post-buckling analysis of functionally graded beams with temperature-dependent physical properties

  • Kocaturk, Turgut;Akbas, Seref Doguscan
    • Steel and Composite Structures
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    • 제15권5호
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    • pp.481-505
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    • 2013
  • This paper focuses on thermal post-buckling analysis of functionally graded beams with temperature dependent physical properties by using the total Lagrangian Timoshenko beam element approximation. Material properties of the beam change in the thickness direction according to a power-law function. The beam is clamped at both ends. In the case of beams with immovable ends, temperature rise causes compressible forces and therefore buckling and post-buckling phenomena occurs. It is known that post-buckling problems are geometrically nonlinear problems. Also, the material properties (Young's modulus, coefficient of thermal expansion, yield stress) are temperature dependent: That is the coefficients of the governing equations are not constant in this study. This situation suggests the physical nonlinearity of the problem. Hence, the considered problem is both geometrically and physically nonlinear. The considered highly non-linear problem is solved considering full geometric non-linearity by using incremental displacement-based finite element method in conjunction with Newton-Raphson iteration method. In this study, the differences between temperature dependent and independent physical properties are investigated for functionally graded beams in detail in post-buckling case. With the effects of material gradient property and thermal load, the relationships between deflections, critical buckling temperature and maximum stresses of the beams are illustrated in detail in post-buckling case.

Vibration and stability of initially stressed sandwich plates with FGM face sheets in thermal environments

  • Chen, Chun-Sheng;Liu, Fwu-Hsing;Chen, Wei-Ren
    • Steel and Composite Structures
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    • 제23권3호
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    • pp.251-261
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    • 2017
  • In this paper, thermal effect on the vibration and stability of initially stressed sandwich plates with functionally graded material (FGM) face sheets is analyzed. Material properties of FGM face sheet are graded continuously in the thickness direction. The variation of FGM properties assumes a simple power law distribution in terms of the volume fractions of the constituents. The governing equations of arbitrarily initially-stressed sandwich plates including the effects of transverse shear deformation and rotary inertia are derived. The initial stress is taken to be a combination of a uniaxial extensional stress and a pure bending stress in the examples. The eigenvalue problems are formed to study the vibration and buckling characteristics of simple supported initially stressed FGM/metal/FGM plates. The effects of volume fraction index, temperature rise, initial stress and layer thickness of metal on the natural frequencies and buckling loads are investigated. The results reveal that the volume fraction index, initial stresses and layer thickness of metal have significant influence on the vibration and stability of sandwich plates with FGM face sheets.

Three dimensional free vibration analysis of functionally graded nano cylindrical shell considering thickness stretching effect

  • Dehsaraji, Maryam Lori;Arefi, Mohammad;Loghman, Abbas
    • Steel and Composite Structures
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    • 제34권5호
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    • pp.657-670
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    • 2020
  • In this paper, vibration analysis of functionally graded nanoshell is studied based on the sinusoidal higher-order shear and normal deformation theory to account thickness stretching effect. To account size-dependency, Eringen nonlocal elasticity theory is used. For more accurate modeling the problem and corresponding numerical results, sinusoidal higher-order shear and normal deformation theory including out of plane normal strain is employed in this paper. The radial displacement is decomposed into three terms to show variation along the thickness direction. Governing differential equations of motion are derived using Hamilton's principle. It is assumed that the cylindrical shell is made of an arbitrary composition of metal and ceramic in which the local material properties are measured based on power law distribution. To justify trueness and necessity of this work, a comprehensive comparison with some lower order and lower dimension works and also some 3D works is presented. After presentation of comparative study, full numerical results are presented in terms of significant parameters of the problem such as small scale parameter, length to radius ratio, thickness to radius ratio, and number of modes.

태양광 어레이 설치 위치 및 각도변경 전후의 태양광 발전 시스템의 출력 변화에 관한 연구 (A Study on PV System Output Changes by PV Array Installation Position and Mount Angle Change)

  • 윤정필;차인수;최정식;김동묵;박종복;하민호;김원배
    • Current Photovoltaic Research
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    • 제2권4호
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    • pp.189-194
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    • 2014
  • In this paper, We have simulated the output variation of the PV arrays installation with position & angle change. The existing 3 solar array system are $43^{\circ}$ southeast and each of the mounting angle is $17^{\circ}$. The PV output power is 240 kW. The composite studied systems in this paper arrays altered 2 PV array among 3 PV array system- the output 144kW. We simulated this system using Solar Pro ver.4.1. The simulation conditions are southwest $43^{\circ}/array$, mount angle $27^{\circ}/array$. Because the southeast have shadow effect-higher mountain The purpose of southwest $43^{\circ}$ is reduce the shadow effect. The simulation results of the suggestion design algorithm compared to 1,590 kWh/year output is increased with the southeast.

DATABASE 기반의 조선업 일정계획 시스템 구축 (A Scheduling System based on DBMS for Shipbuilding)

  • 이동욱;김순겸;이호윤;박성규;이대형;왕지남
    • 한국CDE학회논문집
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    • 제17권1호
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    • pp.26-34
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    • 2012
  • Assembly scheduling in shipbuilding is responsible for determine assembly process orders and departmental production schedule for the block, the basic composite unit of ships. It is necessary much more information to decide production scheduling as the characteristic of shipbuilding which has been more complex and more various and also, a lot of waste of time and of human power is generated in the course of data processing. The target shipbuilding manufacturer of this study use empirical techniques, based on the user's discretion, to compile and to apply data which are scattered in DB storages separately. Because of that reason, the user should not only be performed identification and screening operations but also modification and verification for vast amounts of data, so it is hard to keep the consistency of the data and also the operation time is not constant. Accordingly, the object in this study is by presenting an efficient DB framework to reduce wasting time and man-hour at experienced-oriented process, abate user's manual operations and support an efficient scheduling in assembly processes.

Effect of Heat-Treated Temperature on Surface Crystal Structure and Catalytic Activity of ACF/ZnO Composite under Ultraviolet Irradiation and Ultrasonication

  • Zhang, Kan;Oh, Won-Chun
    • 한국세라믹학회지
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    • 제47권2호
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    • pp.136-141
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    • 2010
  • ACF/ZnO photocatalyst was synthesized by a sol-gel method using activated carbon fiber (ACF) and Zn $(NO_3)_2$ as precursors. Samples were characterized by Brunauer-Emmett-Teller measurements (BET), scanning electron microscope (SEM), X-ray diffraction (XRD), and energy dispersive X-ray (EDX). The XRD results showed that ACF/ZnO composites only included a hexagonal phase by heat-treated temperature at $400^{\circ}C$, $500^{\circ}C$, $600^{\circ}C$, and $700^{\circ}C$. The SEM analysis revealed that the ACF/ZnO composites did not exhibit any morphological changes of the catalyst surface according to the different heat-treated temperatures. The photocatalytic activity of the samples was tested for degradation of methylene blue (MB) solutions under ultraviolet (UV) light and ultrasonication respectively. The results showed that the photocatalytic activity of ACF/ZnO composites heat-treated at $500^{\circ}C$ was higher than other samples, which is ascribed to the fine distribution of ZnO particles on the surface of the ACF. In addition, an ultrasound of low power (50 W) was used as an irradiation source to successfully induce ACF/ZnO composites to perform sonocatalytic degradation of MB. Results indicated that the sonocatalytic method in the presence of ACF/ZnO composites is an advisable choice for the treatments of organic dyes.

Powder Packing Behavior and Constrained Sintering in Powder Processing of Solid Oxide Fuel Cells (SOFCs)

  • Lee, Hae-Weon;Ji, Ho-Il;Lee, Jong-Ho;Kim, Byung-Kook;Yoon, Kyung Joong;Son, Ji-Won
    • 한국세라믹학회지
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    • 제56권2호
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    • pp.130-145
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    • 2019
  • Widespread commercialization of solid oxide fuel cells (SOFCs) is expected to be realized in various application fields with the advent of cost-effective fabrication of cells and stacks in high volumes. Cost-reduction efforts have focused on production yield, power density, operation temperature, and continuous manufacturing. In this article, we examine several issues associated with processing for SOFCs from the standpoint of the bimodal packing model, considering the external constraints imposed by rigid substrates. Optimum compositions of composite cathode materials with high volume fractions of the second phase (particles dispersed in matrix) have been analyzed using the bimodal packing model. Constrained sintering of thin electrolyte layers is also discussed in terms of bimodal packing, with emphasis on the clustering of dispersed particles during anisotropic shrinkage. Finally, the structural transition of dispersed particle clusters during constrained sintering has been correlated with the structural stability of thin-film electrolyte layers deposited on porous solid substrates.

Neural Network Modeling of PECVD SiN Films and Its Optimization Using Genetic Algorithms

  • Han, Seung-Soo
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • 제1권1호
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    • pp.87-94
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    • 2001
  • Silicon nitride films grown by plasma-enhanced chemical vapor deposition (PECVD) are useful for a variety of applications, including anti-reflecting coatings in solar cells, passivation layers, dielectric layers in metal/insulator structures, and diffusion masks. PECVD systems are controlled by many operating variables, including RF power, pressure, gas flow rate, reactant composition, and substrate temperature. The wide variety of processing conditions, as well as the complex nature of particle dynamics within a plasma, makes tailoring SiN film properties very challenging, since it is difficult to determine the exact relationship between desired film properties and controllable deposition conditions. In this study, SiN PECVD modeling using optimized neural networks has been investigated. The deposition of SiN was characterized via a central composite experimental design, and data from this experiment was used to train and optimize feed-forward neural networks using the back-propagation algorithm. From these neural process models, the effect of deposition conditions on film properties has been studied. A recipe synthesis (optimization) procedure was then performed using the optimized neural network models to generate the necessary deposition conditions to obtain several novel film qualities including high charge density and long lifetime. This optimization procedure utilized genetic algorithms, hybrid combinations of genetic algorithm and Powells algorithm, and hybrid combinations of genetic algorithm and simplex algorithm. Recipes predicted by these techniques were verified by experiment, and the performance of each optimization method are compared. It was found that the hybrid combinations of genetic algorithm and simplex algorithm generated recipes produced films of superior quality.

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