• Proceedings of the KSR Conference
• /
• 2005.05a
• /
• pp.491-497
• /
• 2005

Brake system is indispensible functional part to the transportation machines such as railroad cars, and all of industrial machines. It is mechanical element to stop the movement or slow the speed, transforming kinetic energy of motion object into thermal energy through solid friction. According that recently the railroad cars have become high-speed, the technique in braking domain to secure the overall braking effort is making rapid progress. In particular, material development and manufacturing process are so important to secure friction performance, which is the core in braking performance of mechanical brake units. Wear of brake disk could mainly result in the diminishment of its life span due to thermal cracking, so the endurance against high temperature is required. On the other hand, in this case, the problem is that the side wear of pad, relative material is slightly increased because of enlargement of plastic deformation. It is necessary, therefore, to develop a disk material that will be used in the Tilting System mechanical brake units. The purpose of this paper is to make a study prior to developing brake disk of Tilting Train travelling at 200km/h and to propose the component of brake disk. Accordingly, I will conduct sufficient researches on technical documents of brake disk, that are basic documentations, analyze an impact on components, and further, considering braking degree of train, study for the basic proposal on brake disk's component of the train travelling at 200km/h, which has relatively minor influence of heat stress and maintains the friction. In this respect, I would like to investigate friction characteristics between disk and relative friction material via Test on some possible test segments, analyze and propose friction performance, temperature impact and so forth coming from the contact with pad, relative material to demonstrate the friction characteristics.

• Journal of the Korea Furniture Society
• /
• v.25 no.2
• /
• pp.79-86
• /
• 2014

Furniture can be a product of design and is considered a form of a decorative art. Architectural works are often perceived as cultural symbols and as works of art. Korean traditional architectural form and wooden furniture were improved by adding up an organic coordination in the interior space. Furniture adds beauty of life by being coordinated with the interior space with its particular characteristic in the form of architectural structure. Architecture and furniture are also being improved in a more natural and diverse way. Therefore, in this research, from the choice of the location, Korean traditional architecture is considered to be coordinated with the nature, and the technical skill is lessened to express its beauty. There is a presence of elegance yet robust combination of simplicity and beauty. In addition, the traditional architecture and wooden furniture are completely expressed structurally with coordination of the outstanding design and solid structure according to the thrifty living in the Confucian ideas which influenced the Korean traditional society. The representative of Korean traditional architecture, Baeheulrim pillar, has worked as motive because of its visual comfort caused by optical illusion and formative elements. The small portable dining table (Soban) which reflects the characteristic of Korean unique tradition and the sensitivity of Koreans has been reinterpreted through the motive in this research. As a result, it has shown the possibility as the design element to change the aesthetic structure. In the modern society, cultural identity plays a vital role. Therefore, this research can be used as reference for the new concept of furniture - making. It could be a combination of modern people, lifestyle and living space by creating the Korean image suitable for the modern society.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.37 no.7
• /
• pp.7-16
• /
• 2000

This paper reports a methodology and its application for extracting cell capacitances and parasitic capacitances in a stacked DRAM cell structure by a numerical technique. To calculate the cell and parasitic capacitances, we employed finite element method (FEM), The three-dimensional DRAM cell structure is generated by solid modeling based on two-dimensional mask layout and transfer data. To obtain transfer data for generating three-dimensional simulation structure, topography simulation is performed. In this calculation, an exemplary structure comprising 4 cell capacitors with a dimension of $2.25{\times}1.75{\times}3.45{\mu}m^3$, 70,078 nodes with 395,064 tetrahedra were used in ULTRA SPARC 10 workstation. The total CPU time for the simulation was about 25 minutes, while the memory size of 201MB was required. The calculated cell capacitance is 24.34fF per cell, and the influential parasitic capacitances in a stacked DRAM cell are investigated.

• Journal of the Korean Geotechnical Society
• /
• v.27 no.3
• /
• pp.75-83
• /
• 2011

Emerging issues related with fully coupled Thermo-Hydro-Mechanical (THM) behavior of unsaturated soil demand the development of a numerical tool in diverse geo-mechanical and geo-environmental areas. This paper presents general governing equations for coupled THM processes in unsaturated porous media. Coupled partial differential equations are derived from three mass balances equations (solid, water, and air), energy balance equation, and force equilibrium equation. With Galerkin formulation and time integration of these governing equations, finite element code is developed to find nonlinear solution of four main variables (displacement-u, gas pressure-$P_g$), liquid pressure-$P_1$), and temperature-T) using Newton's iterative scheme. Three cases of numerical simulations are conducted and discussed: one-dimensional drainage experiments (u-$P_g-P_1$), thermal consolidation (u-$P_1$-T), and effect of pile on surrounding soil due to surface temperature variation (u-$P_1$-T).

• Smart Structures and Systems
• /
• v.13 no.4
• /
• pp.615-636
• /
• 2014

Aluminium Foam Sandwich (AFS) panels are becoming always more attractive in transportation applications thanks to the excellent combination of mechanical properties, high strength and stiffness, with functional ones, thermo-acoustic isolation and vibration damping. These properties strongly depend on the density of the foam, the morphology of the pores, the type (open or closed cells) and the size of the gas bubbles enclosed in the solid material. In this paper, the vibrational performances of two classes of sandwich panels with an Alulight(R) foam core are studied. Experimental tests, in terms of frequency response function and modal analysis, are performed in order to investigate the effect of different percentage of porosity in the foam, as well as the effect of the random distribution of the gas bubbles. Experimental results are used as a reference for developing numerical models using finite element approach. Firstly, a sensitivity analysis is performed in order to obtain a limit-but-bounded dynamic response, modelling the foam core as a homogeneous one. The experimental-numerical correlation is evaluated in terms of natural frequencies and mode shapes. Afterwards, an update of the previous numerical model is presented, in which the core is not longer modelled as homogeneous. Mass and stiffness are randomly distributed in the core volume, exploring the space of the eigenvectors.

• Journal of the Korean Society of Costume
• /
• v.32
• /
• pp.117-130
• /
• 1997

The purpose of this study were to identify the design elements and the changing flow of advertisement from 1970's to 1990's by using content analysis of men's magazines. Finding were as followed; First through the analysis of men's wear advertisement in magazine it was found that the closer to 1990's the more various men's wear styles and backgrounds were advertized. These were more image oriented than product oriented. Since 1980 the advertisement about the licenced and the imported brands have been increased and the serial advertisement has shown more fre-quently than the 1-page advertisement since 1990's ; Second two piece suit was dominated in men's wear during 1970's and 1980's From 1990's this style was decresed in stead combi suit was increased. In 1970's the X silhouette was infashion and the y and the X silhouette was in fashion and the y and X sillhouette were increased during 1980's . The H silhouette was dominated in 1990's The brighter and the more various colors appeared in 1990's than in 1970's. The brighter and the more various colors appeared in 1990's than in 1970's The solid pattern was the main flow in men's wear however the stripes and the the check patterns were added in 1990's Third single breasted jacket style with two buttons and tailored collar was in fashion during 1970's . The length of the v-zone was shorter than half at this time however it was lengthened in 1980's . Also the the length of the jacket was lengthened. In 1990's the double breasted jacket style and two buttons were increased. The length of the v-zone and jacket were also lengthened.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.17 no.1
• /
• pp.141-152
• /
• 1993

A generalized method is presented for shape design sensitivity analysis of axisymmetric thermal conducting solids. The shape sensitivity formula of a general performance functional arising in shape optimal design problem is derived using the material derivative concept and the adjoint variable method. The method for deriving the formula is based on standard axisymmetric boundary integral equation formulation. It is then applied to obtain the sensitivity formulas for temperature and heat flux constraints imposed over a small segment of the boundary. To show the accuracy of the sensitivity analysis, numerical implementations are done for three examples. Sensitivities calculated by the presented method are compared with analytic sensitivities for two examples with analytic solutions, and compared with sensitivies by finite difference for a cooling fin example.

• Resources Recycling
• /
• v.23 no.5
• /
• pp.28-35
• /
• 2014

The basic properties of cow and chicken manure such as proximate analysis and element analysis were estimated and the comparison to energy characteristics of carbonization residue between cow and chicken manure was evaluated. The optimum carbonization condition of cow and chicken manure was decided by total heating value of carbonization residue which was expressed by multiplying low heating value by yield. The optimum carbonization conditions for carbonization time and temperature can be decided by 15 min, and $350^{\circ}C$ for chicken manure, and 20 min, and $300^{\circ}C$ for cow manure. At the optimum carbonization conditions, low heating values for the carbonization residue of cow and chicken manure are evaluated by 4,378kcal/kg, and 3,462kcal/kg, respectively. The residues of cow manure were satisfied with the standard of solid fuel product. However, the residue of chicken should be improved by materials changes to be used as a renewable energy source.

• Journal of Korea Foundry Society
• /
• v.23 no.3
• /
• pp.137-146
• /
• 2003

The main purpose of this study is to investigate the effects of process parameter on alpha-case formation of Ti and TiAl castings. The previous studies showed that the molten titanium is excessively reactive to the refractory oxide mold, resulting in alpha-caes of the titanium castings regardless of composition of titanium alloys. However, the behavior of the alpha-case formation of TiAl alloy is not consistent with conventional titanium alloy. In order to investigate the alpha-case formation of Ti and TiAl castings with process parameter, especially the associated factors of investment mold such as mold material, binder and mold preheating temperature. An attempt has been made to characterize the alpha-case of titanium casting by using optical microscope, EDS, XRD, EMPA and hardness profiles. The formation of the alpha-case on the surface of pure titanium during investment casting was rather by that of solid solution with metallic element from mold material. The required mold strength was obtained with $CaZrO_3$ because of the possibility of using water soluble binder. However, the separation phenomenon between facing and back-up mold materials should be considered. The interfacial reaction of TiAl alloy showed different behavior from that of pure titanium and $Al_2O_3$ was best mold materials. The effect of binder as well as mold material on the formation of alpha-case was significant.

• Journal of the Korean association of regional geographers
• /
• v.7 no.4
• /
• pp.81-92
• /
• 2001

Main debates in the modern geographical thoughts had been developed around the regional geography. Because regional geography had been regarded as a raison d'etre of geography, it remains solid status in geography curriculum. But unscientific nature of regional geography was the main problem of modern geography. Modern geography has developed the logical legitimation of regional geography, instead of research procedures. We examine the logic of modern geographical thoughts from 3 worldview. Here we represented the part - the whole relationship as the primary category, and classify these into three type according to the implicit proposition about the relationship. One is the organic view, which assume that the whole is greater than the sum of the parts. This view was the primary proposition held by the modem geographers. This view regarded the region as organic complex, and presume the unit region which is irreducible to the elements. The other is mechanic view, which presuppose that the whole is the sum of the parts. This view comprehend region by means of spatial order, in order to simplify the complex reality. Then we compare real condition with assumption. These two view held static assumption. Now, the third view regarded the part- the whole relationship as being dynamic. Most geographers held the organic view, although someone suggests the idea of harmony, the others suggests the idea of complex. But these view presumes the pre-industrial society in which the genre de vie was main principle of social order. Therefore It could not comprehend the regional concept in the context of the urbanization and industrialization.