• Structural Engineering and Mechanics
• /
• v.60 no.6
• /
• pp.1063-1077
• /
• 2016

Components manufactured from composite materials are frequently subjected to superimposed mechanical and thermal loadings during their operating service. Both types of loadings may cause fracture and failure of composite structures. When composite cross-ply laminates of type [$0_m/90_n]_s$ are subjected to uni-axial tensile loading, different types of damage are set-up and developed such as matrix cracking: transverse and longitudinal cracks, delamination between disoriented layers and broken fibers. The development of these modes of damage can be detrimental for the stiffness of the laminates. From the experimental point of view, transverse cracking is known as the first mode of damage. In this regard, the objective of the present paper is to investigate the effect of transverse cracking in cross-ply laminate under thermo-mechanical degradation. A Finite Element (FE) simulation of damage evolution in composite crossply laminates of type [$0_m/90_n]_s$ subjected to uni-axial tensile loading is carried out. The effect of transverse cracking on the cross-ply laminate strength under thermo-mechanical degradation is investigated numerically. The results obtained by prediction of the numerical model developed in this investigation demonstrate the influence of the transverse cracking on the bearing capacity and resistance to damage as well as its effects on the variation of the mechanical properties such as Young's modulus, Poisson's ratio and coefficient of thermal expansion. The results obtained are in good agreement with those predicted by the Shear-lag analytical model as well as with the obtained experimental results available in the literature.

• Philosophy of Education
• /
• no.39
• /
• pp.191-221
• /
• 2009

The aim of this study is to analyse of elements and structure of consciousness theory in the 1887 Psychology written by John Dewey, and to research its educational implications. Conclusions are as follows: Firstly, consciousness theory articulated in first edition of Dewey's Psychology was influenced by neo-Hegelian G. S. Hall, and then characteristics of its theory was metaphysical and idealistic. But after of researching the work of William James, his approach to consciousness changed surprisingly from idealistic to experimental. His experimental approach and scientific attitude to it influenced the formation and development of advanced theories in his epistemology, axiology and pedagogy. Secondly, the structure of consciousness expressed by Dewey has three forms such as knowledge, feeling and will(or volition). This forms are too dynamic and unitary. Dewey considered cognition, feeling, will to be integral functions of each self. The tripartite functions of self, moreover, are unified in will. In other word, will combines subjective feeling and objective knowledge as one self. Will regulates impulse because it powers some stimulus into activity of self. In this view point, his theory of consciousness differs from traditional theories about consciousness for emphasizing dynamic relations and functions. Thirdly, Dewey's theory of consciousness will give some important implications to educational field. It is necessary to fundamental arguments about conscious conditions of learners as a human. For it is impossible to establish some aim of learning, to organize meaningful contents of learning, and also to create some effective methods of learning without consideration of this conditions. And it is important to construct and organize the contents and methods of learning for widening and deepening of educational experiences. Then consciousness and experiences of learners interact each other, so then they will produce some meaningful results of learning in this process.

• The Research Journal of the Costume Culture
• /
• v.15 no.1 s.66
• /
• pp.152-168
• /
• 2007

The aim of this study is to shed light on essentials of Suprematist artists focusing on Malevich and their works in relation to modem design, and to examine their roles in the modem design industry compared to those of modem designers. The study obtains the following result on Suprematist artists and their works in Russian avant-garde in terms of modem design. Firstly, Suprematist artists had a great deal of interest in practical design although it seemed Suprematist were replaced by utilitarianism in avant-garde during the Russian revolution. Secondly, Suprematist artists were the first artists to bring the birth of modem design trends by applying their art in geometric forms to clothing and fabric design as well as ornaments and handicraft. Thirdly, the artists' attempt to work with needle workers made it possible to set achievements in design and modem decorative art exhibitions in various fields of art-life. As for the role of modem designers, Suprematist artists including Malevich have significant meanings as follows: Firstly, Malevich was a creative, future-oriented artistic designer who realized zaum of painting on the stage and created suprematistic mode in a cosmic point of view in order to agree with the environment. Secondly, Suprematist artists knew the importance of works that were produced by craftsmen and worked together with them. Therefore, the designers could maintain fabric decoration in difficult conditions knowing the importance of the high value-added industry. Thirdly, they were artists in real life who embodied the ideas and theories of Suprematist in sample works by recognizing the need of changes in life environment: they planned to set a new visual world in art but did not confine the idea only to painting.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.18 no.2
• /
• pp.432-445
• /
• 1994

From a theoretical analysis point of view, the 2-stage precipitator is decomposed into two units: charging cell and collecting cell. Collection efficiency predictions of the two-stage parallel-plate electrostatic precipitator have been performed theoretically incorporating with the charging and the collecting cells. Particle trajectorise passing the charging cell have been modeled as a simple one. Particle charge distribution at the outlet of the charging cell is calculated through integration of the present unipolar combined charging rate along the entire particle trajectory, and average charge of particles at the outlet of the charging cell is obtained from the particle charge distribution. As for the collecting cell, the diminution of particle concentration along the longitudinal direction of the collecting cell is investigated considering the conventional Deutsch's theory and the laminar theory. One should note that the collection efficiency formula derived is based on monodisperse aerosols. It has been confirmed through the analysis that predictions of particle charge by applying White's unipolar diffusion charging theory overpredict actual cases in the continuum regime, while predictions by Fuch's unipolar diffusion charging theory indicate the reasonable result in the same regime. Theoretical predictions of collection efficiency are also compared with the available experimental results. Comparisons show that the experimental results are consistently located in the collection efficiency region bounded by the two limits, the Deutsch and the laminar collection efficiencies. Finally design parameters of the 2-stage electrostatic precipitator have been investigated systematically through the one-variable-at-a-time method in terms of collection efficiency. Applied voltages on the corona wire of the charging cell and the plate of the collecting cell, and the average air velocity have been selected as the design parameters.

• Journal of Korean Association for Spatial Structures
• /
• v.6 no.1 s.19
• /
• pp.55-63
• /
• 2006

Concrete-filled steel columns consist of circular, square or rectangular hollow sections filled concrete. Much research has studied for the behavior of concrete-filled steel structures. The advantages from structural point of view are the triaxial confinement of the concrete within the section, and the fire resistance of the column which largely depends on the residual capacity of the concrete core. The axial capacity of a concrete-filled rectangular or circular section is enhanced by the confining effect of the steel section on the concrete which depends in the magnitude on the shape of the section and the length of the column. Buckling tends to reduce the benefit of confinement on the squash load as the column slenderness increases. In circular sections it is possible to develop the cylinder strength of the concrete. When compare with reinforced concrete columns, the concrete-filled composite column possesses much better strength and ductility in shear and generally in flexure also. Many researches are being conducted about concrete filled steel column to get these advantages in building design. In this paper it is provided to the basic experimental study of compression behavior of the circular and rectangular tubular steel pipe filled with concrete.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
• /
• v.3B no.3
• /
• pp.147-154
• /
• 2003

This paper presents a high-frequency boost type ZVS-PWM chopper-fed DC-DC power converter with a single active auxiliary edge-resonant snubber at the load stage which can be designed for power conditioners such as solar photovoltaic generation, fuel cell generation, battery and super capacitor energy storages. Its principle operation in steady-state is described in addition to a prototype setup. The experimental results of boost type ZVS-PWM chopper proposed here, are evaluated and verified with a practical design model in terms of its switching voltage and current waveforms, the switching v-i trajectory and the temperature performance of IGBT module, the actual power conversion efficiency, and the EMI of radiated and conducted emissions, and then discussed and compared with the hard switching scheme from an experimental point of view. Finally, this paper proposes a practical method to suppress parasitic oscillation due to the active auxiliary resonant switch at ZCS turn-off mode transition with the aid of an additional lossless clamping diode loop, and can be reduced the EMI conducted emission.

• Earthquakes and Structures
• /
• v.13 no.2
• /
• pp.165-176
• /
• 2017

Multi-Axial Testing System (MATS) is a 6-DOF loading system located at National Center for Research on Earthquake Engineering (NCREE) in Taiwan for advanced seismic testing of structural components or sub-assemblages. MATS was designed and constructed for a large variety of structural testing, especially for the specimens that require to be subjected to vertical and longitudinal loading simultaneously, such as reinforced concrete columns and lead rubber bearings. Functionally, MATS consists of a high strength self-reacting frame, a rigid platen, and a large number of servo-hydraulic actuators. The high strength self-reacting frame is composed of two post-tensioned A-shape reinforced concrete frames interconnected by a steel-and-concrete composite cross beam and a reinforced concrete reacting base. The specimen can be anchored between the top cross beam and the bottom rigid platen within a 5-meter high and 3.25-meter wide clear space. In addition to the longitudinal horizontal actuators that can be installed for various configurations, a total number of 13 servo-hydraulic actuators are connected to the rigid platen. Degree-of-freedom control of the rigid platen can be achieved by driving these actuators commanded by a digital controller. The specification and information of MATS in detail are described in this paper, providing the users with a technical point of view on the design, application, and limitation of MATS. Finally, future potential application employing advanced experimental technology is also presented in this paper.

• Journal of The Korean Association For Science Education
• /
• v.19 no.1
• /
• pp.78-90
• /
• 1999

This study investigated the high school students' and science teachers' understanding of idealization involved in the physics experiment. Major research questions are as follows: (1) what kind of ideal conditions do subjects identify from the presented experimental context? (2) do subjects think how well ideal conditions are satisfied with the experiment? (3) how well do subjects expect the effect of idealization on the experimental result? (3) what kind of view point do science teachers have about the ideal condition involved in the experiment? A total of 85 subjects were given 6 questions related with the research questions I. 2. and 3. with simple experiment about the brightness of the bulbs connected with parallel to the battery. And another 4 questions for the forth research question were given to 42 science teachers. Subjects' responses were summarized and used to draw the implications for the teaching of physics experiment.

• Journal of Digital Convergence
• /
• v.18 no.4
• /
• pp.419-424
• /
• 2020

The purpose of this study is to find out whether changed interactions due to reformatting has a significant effect on the play attribute of children's play from an instrumental point of view. Based on the study of Roser Caillois theory of play (Agon, Mimicry, Area, Ilinx) and previous studies, a questionnaire was written and experimental design was carried out through brick stack which are most preferred in the whole development of children. Brick stack were selected from physical and electronic spaces and the survey was conducted with children's experiences by dividing into experimental group and comparative group. Correlation and T-test results, the brick stack by reformating showed significant difference in the play attributes (Agon, Mimicry, Area, Ilinx) of Rose Caillois and we found that the effectiveness of play is doubled in the electronic space. Play properties evenly distributed in electronic space brick stacking suggest that pleasure and fun can double.

• Journal of the Korean Chemical Society
• /
• v.47 no.6
• /
• pp.541-546
• /
• 2003

Experimental vapor pressure measurements available in the literature for the inert gases have been rigorously analyzed and used to evaluate the constants A, B, C, D, and exponent of the following equation in the form of reduced vapor pressure and reduced temperature : $InP_r=A+{\frac{B}{T_r}+CInT_r+DT_n^r}$ According to varying exponent n all four constants have been obtained for the inert gases by the error analysis. This has provided us the best n and four constants for each of the inert gases ; Argon, krypton, xenon, helium, and neon. In order to obtain the calculated vapor pressure by the above equation, only the normal boiling point and the critical pressure and critical temperature are necessary to get the vapor pressure for an overall average deviation of 0.31 % for 406 experimental vapor pressure points consisting of five gases available in the literature. The average deviation for argon, krypton, and xenon is 0.24%, 0.09%, and 0.22%, respectively, for neon 1.31% and for helium 0.61%. These results are not unexpected in view of the significant quantum effects associated with helium and to a lesser degree with neon.