• Title/Summary/Keyword: Free-form Surface

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John Ruskin and Herman Muthesius - A Comparative Study on the Architectural Theories of the Early Modern Movements in Britain and Germany - (근대건축 형성기 영국과 독일의 건축이론 비교 연구 -러스킨과 무테지우스의 이론을 중심으로-)

  • Kim, Bong-Ryol
    • Journal of architectural history
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    • v.1 no.2 s.2
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    • pp.116-136
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    • 1992
  • Architectural essence of John Ruskin's discourse can resolve itself into natural beauty, craftmanship, and truth in structure, surface, and process. His theories became disciplines of modern English school, Art and Craft and Free architecture, in aspects of organic architecture, morality, and rationality. These concepts disseminated continental Art Nouveau and also became it's basic principles. But his empirical theories hated use of machine, and should find a ideal model in medieval romanticism of Gothic. Anti-machine, as a instictive guideline of English modern architecture, couldn't cope with the industrialization of 20th century, and Gothic revival interfered with creating a new style. Muthesius' discourses were taught by the power of group movements and modern concept of form in English school, originally by Ruskin. But he accepted the potentiality of machine and mass production, and stressed creating the new German style suitable with machine. With the progress of Deutscher Werkbund, his theories were advanced to 'quality' connected with craftmanship, to discourse on mechanical 'form', and lastly to 'standardization and type' for mass production. Mechanical functionalism of Muthesius and DWB were sophiscated and handed down to Bauhaus, and then finally helped establishment of the Modern Architecture and Internationalism. Both English and German modern architecture owed their contribution as well as limitation to Ruskin and Muthesius as theorists. Through this comparative study, we can see the priority of theory to practice, the theoretical justification based on insight for its society and future, and the practical character of theory itself.

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A Study on the Crack Growth Behavior of a Inclined Crack in a Non-Uniform Thickness Material (두께가 일정하지 않은 재료에서 경사진 균열의 성장거동에 관한 연구)

  • 조명래;표창률;박종주;고명훈
    • Journal of the Korean Society of Safety
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    • v.12 no.4
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    • pp.27-38
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    • 1997
  • The effect of geometry factors on the combined mode stress intensity factor behaviors of a slant crack in a non-uniform thickness material was analysed by 2-dimensional theoretical analysis. The analysis is based on the Laurent's series expansions of complex potentials where the complex coefficients of the series are determined from the compatibility and the equilibrium conditions of the thickness interface and the stress free conditions of the crack surface. In numerical calculations the perturbation technique is employed. The expressions for the crack tip stress intensity factor are given in the form of power series of dimensionless crack length $\lamda$, and the function of crack slant angle $\alpha$ and thickness ratio $\beta$. The results of numerical calculations for each problems are represented as the correction factors F($\lamda$, $\alpha$, $\beta$). The results clearly show the following characteristics : The correction factors of the combined mode stress intensity factors for a non-uniform thickness material can be defined in the form of F($\lamda$, $\alpha$, $\beta$). The stress intensity factor values for a given crack length are decreased with increase of thickness ratio $\beta$.

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Numerical Simulation of Turbulent Flow around KLNG Hull Form with Different Scale Ratio (다른 축척비를 가진 KLNG 선형주위 유동장 시뮬레이션)

  • Ha, Yoon-Jin;Lee, Young-Gill;Kang, Bong-Han
    • Journal of the Society of Naval Architects of Korea
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    • v.51 no.1
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    • pp.8-15
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    • 2014
  • In this study, flow characteristics around the hull form of KLNG are investigated by numerical simulations. The numerical simulations of the turbulent flows with the free surface around KLNG have been carried out at Froude number 0.1964 using the FLUENT 6.3 solver with Reynolds stress turbulence model. Several GEOSIM models are adopted to consider the scale effect attendant on Reynolds number. Furthermore, a full scale ship is calculated and the result is compared with the numerical results of GEOSIM models. The calculated results of GEOSIM models and the full scale ship are compared with the experiment data of MOERI towing tank test and Inha university towing tank test. Moreover, wake distribution on the propeller plane of the full scale ship is estimated using the numerical results of GEOSIM models. The prediction result is directly compared with the simulation result in full scale.

Hierarchically porous carbon aerogels with high specific surface area prepared from ionic liquids via salt templating method

  • Zhang, Zhen;Feng, Junzong;Jiang, Yonggang;Feng, Jian
    • Carbon letters
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    • v.28
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    • pp.47-54
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    • 2018
  • High surface carbon aerogels with hierarchical and tunable pore structure were prepared using ionic liquid as carbon precursor via a simple salt templating method. The as-prepared carbon aerogels were characterized by nitrogen sorption measurement and scanning electron microscopy. Through instant visual observation experiments, it was found that salt eutectics not only serve as solvents, porogens, and templates, but also play an important role of foaming agents in the preparation of carbon aerogels. When the pyrolyzing temperature rises from 800 to $1000^{\circ}C$, the higher temperature deepens the carbonization reaction further to form a nanoporous interconnected fractal structure and increase the contribution of super-micropores and small mesopores and improve the specific surface area and pore volume, while having few effects on the macropores. As the mass ratio of ionic liquid to salt eutectics drops from 55% to 15%, that is, the content of salt eutectics increases, the salt eutectics gradually aggregate from ion pairs, to clusters with minimal free energy, and finally to a continuous salt phase, leading to the formation of micropores, uniform mesopores, and macropores, respectively; these processes cause BET specific surface area initially to increase but subsequently to decrease. With the mass ratio of ionic liquids to salts at 35% and carbonization temperature at $900^{\circ}C$, the specific surface area of the resultant carbon aerogels reached $2309m^2g^{-1}$. By controlling the carbonization temperature and mass ratio of the raw materials, the hierarchically porous architecture of carbon aerogels can be tuned; this advantage will promote their use in the fields of electrodes and adsorption.

Identification of Functional Site of S-Modulin

  • Tachibanaki, Shuji;Nanda, Kumiko;Sasaki, Kenji;Ozaki, Koichi;Kawamura, Satoru
    • Journal of Photoscience
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    • v.9 no.2
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    • pp.281-283
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    • 2002
  • S-modulin in frog or its bovine homologue, recoverin, is a 26 kDa EF-hand $Ca^{2+}$-binding protein found in rod photoreceptors. The $Ca^{2+}$ -bound form of S-modulin binds to rhodopsin kinase (Rk) and inhibits its activity. Through this regulation, S-modulin is believed to modulate the light-sensitivity of a rod. In the present study, we tried to identify the interaction site of the $Ca^{2+}$ -bound form of S-modulin to Rk. First, we mapped roughly the interaction regions by using partial peptides of S-modulin. The result suggested that a specific region near the amino terminus is the interaction site of S- modulin. We then identified the essential amino acid residues in this region by using S-modulin mutant proteins: four amino acid residues were suggested to interact with Rk. These residues are located in a small closed pocket in the $Ca^{2+}$-free, inactive form of S-modulin, but exposed to the surface of the molecules in the $Ca^{2+}$ -bound, active form of S-modulin. Two additional amino acid residues were found to be crucial for the $Ca^{2+}$ -dependent conformational changes of S-modulin. The present study firstly identified the functional site of S-modulin, a member of a neuronal calcium sensor protein family.in family..

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Improvement of resistance performance of the 4.99 ton class fishing boat (4.99톤 어선의 저항성능 개선)

  • JEONG, Seong-Jae;AN, Heui-Chun;KIM, In-Ok;PARK, Chang-Doo
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.53 no.4
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    • pp.446-455
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    • 2017
  • The improvement of resistance performance for the 4.99 ton class fishing boats was shown. The 4.99 ton fishing boats are the most commonly used one in the Korean coastal region. The evaluation of resistance performance was estimated by the Computational Fluid Dynamics (CFD) analysis. The CFD simulation was performed by the validation for various types of bow shapes on the hull. The optimized hull form from the simulation was selected and showed the best resistance performance. This hull type was tested on the towing tank in the National Institute of Fisheries Science (NIFS). The effective horsepower (EHP) was estimated by the resistance test on the towing tank with the bare hull condition. The drag force on the three service speed conditions was obtained for the resistance analysis to power prediction. The measured drag forces are compared with the results from the CFD simulation with one another. As results of the model tests, it was confirmed that the shape of the bow is an important factor in the resistance performance. The effective horsepower decreased about 30% in comparison with the conventional hull form. Also, the resistance performance improved the reduction of required horsepower, which especially contributed to the energy-saving for the fisheries industry. In the CFD analysis, the resistance performance improved slightly. In this case, the ratio of the residual resistance ($C_R$) in the total resistance ($C_T$) was high. Therefore, the CFD analysis was not enough to satisfy with reflection for the free surface and wave form in the CFD procedure. Both model test and CFD calculation in this study can be applied to the initial design process for the coastal fishing vessel.

A Study of Theoretical Method and Application to Laboratory Tests for Three-dimensional Transient Seepage Analysis (삼차원(三次元) 침투류해석(浸透流解析)을 위한 이론적(理論的) 방법(方法)과 실험적용예(實驗適用例)에 관(關)한 고찰(考察))

  • Jin, Byung Ik;Kim, Jae Hong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.4 no.2
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    • pp.13-24
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    • 1984
  • The main part of this thesis deals with a three-dimensional transient seepage flow, discussing its fundamental conception into Which the mathematical analysis was introduced based upon the finite element method, propriety of geometrical analysis and flow movement of seepage water. As is commented in the body of the report, the saturated-unsaturated method with respect to the free water surface method is revealed to have the relative merits and demerits. Generally, the unknown sections in the form of free water surface matters in case that tunnels or pores appear. On the other hand, the applicable range is quite large and variable to the methods accordingly. Also, an example as to the seepage analysis in the rock bed section is described. An unfavorable time-consuming problem is inevitale because the complicated and widely multifarious joints and faults are responsible for the intensity of seepage flow.

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Ultrahigh Vacuum Technologies Developed for a Large Aluminum Accelerator Vacuum System

  • Hsiung, G.Y.;Chang, C.C.;Yang, Y.C.;Chang, C.H.;Hsueh, H.P.;Hsu, S.N.;Chen, J.R.
    • Applied Science and Convergence Technology
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    • v.23 no.6
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    • pp.309-316
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    • 2014
  • A large particle accelerator requires an ultrahigh vacuum (UHV) system of average pressure under $1{\times}10^{-7}$ Pa for mitigating the impact of beam scattering from the residual gas molecules. The surface inside the beam ducts should be controlled with an extremely low thermal outgassing rate under $1{\times}10^{-9}Pa{\cdot}m^3/(s{\cdot}m^2)$ for the sake of the insufficient pumping speed. To fulfil the requirements, the aluminum alloys were adopted as the materials of the beam ducts for large accelerator that thanks to the good features of higher thermal conductivity, non-radioactivity, non-magnetism, precise machining capability, et al. To put the aluminum into the large accelerator vacuum systems, several key technologies have been developed will be introduced. The concepts contain the precise computer numerical control (CNC) machining process for the large aluminum ducts and parts in pure alcohol and in an oil-free environment, surface cleaning with ozonized water, stringent welding process control manually or automatically to form a large sector of aluminum ducts, ex-situ baking process to reach UHV and sealed for transportation and installation, UHV pumping with the sputtering ion pumps and the non-evaporable getters (NEG), et al. The developed UHV technologies have been applied to the 3 GeV Taiwan Photon Source (TPS) and revealed good results as the expectation. The problems of leakage encountered during the assembling were most associated with the vacuum baking which result in the consequent trouble shootings and more times of baking. Then the installation of the well-sealed UHV systems is recommended.

Numerical Analysis on the Wave Resistance by the Theory of Slender Ships (세장선 이론에 의한 조파저항의 수치 해석)

  • Kim, In Chull
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.23 no.3
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    • pp.1-1
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    • 1987
  • The accurate prediction of the ship wave resistance is very important to design ships which operate satisfactorily in a wave environment. Thus, work should continue on development and validation of methods to compute ship wave patterns and wave resistance. Research efforts to improve the prediction of ship waves and wavemaking resistance are categorized in two major areas. First is the development of higher-order theories to take account of the nonlinear effect of the free surface condition and improved analytical treatment of the body boundary condition. Second is the development of direct numerical methods aimed at solving body and free-surface boundary conditions as accurately as possible. A new formulation of the slender body theory for a ship with constant speed is developed by Maruo. It is quite different from the existing slender ship theory by Vossers, Maruo and Tuck. It may be regarded as a substitute for the Neumann-Kelvin approximation. In present work, the method of asymptotic expansion of the Kelvin source is applied to obtain a new wave resistance formulation in fluid of finite depth. It takes a simple form than existing theory.

Elastic Wave Propagation in Monoclinic System Due to Transient Line Load

  • Kim, Yong-Yun
    • The Journal of the Acoustical Society of Korea
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    • v.17 no.2E
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    • pp.53-58
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    • 1998
  • In this paper, we study the response of several anisotropic systems to buried transient line loads. The problem is mathematically formulated based on the equations of motion in the constitutive relations. The load is in form of a normal stress acting with arbitrary axis on the plane of monoclinic symmetry. Plane wave equation is coupled with vertical shear wave, longitudinal wave and horizontal shear wave. We first considered the equation of motion in reference coordinate system, where the line load is coincident with symmetry axis of the orthotrioic material. Then the equation of motion is transformed with respect to general coordiante system with azimuthal angle by using transformation tensor. The load is first described as a body force in the equations of the motion for the infinite media and then it is mathematically characterized. Subsequently the results for semi-infinite spaces is also obtained by using superposition of the infinite medium solution together with a scattered solution from the free surface. Consequently explicit solutions for the displacements are obtained by using Cargniard-DeHoop contour. Numerical results which are drawn from concrete examples of orthotropic material belonging to monoclinic symmetry are demonstrated.

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