• Composites Research
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• v.26 no.6
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• pp.392-397
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• 2013

Functionally graded materials graded continuously and discretely, and are modeled using modified Mori- Tanaka and self-consistent methods. The proposed micromechanics model accounts for multi-phase heterogeneity and arbitrary number of layers. The influence of geometries and distinct elastic material properties of each constituent and voids on the effective elastic properties of FGM is investigated. Numerical examples of different functionally graded materials are presented. The predicted elastic properties obtained from the current model agree well with experimental results from the literature.

• Journal of the Korean Society of Costume
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• v.55 no.6 s.96
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• pp.109-124
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• 2005

The object of this study was to identify the production technique and immediate constituent of lingerie by examining the materials and the sewing techniques. Various papers are referenced for theoretical study and the elements and techniques of lingerie are analyzed based on photographical materials. From the late 20C century to the present time was the research time period. This paper concludes as follows: 1 Decorative method: Lace, Ribbons, piping, elastic bands were some of the decorative materials attached to the garments by zigzag stitch. 2. Flat pattern making: Lingerie patterns were drafted in smaller size than the patterns of outer garments. Bias cut would be applied for the noll-stretchable fabrics. 3. Draping: Bias grain would be applied for the non-stretch fabric. When draping stretch fabrics, follow the grain line of the fabrics and pull the fabric so that it could fit onto the body. 4. Production technique: Straight stitch would be applied for non-stretch fabrics. Zigzag stitch would be applied for stretch fabrics.

• Journal of Powder Materials
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• v.28 no.6
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• pp.502-508
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• 2021

SiAlON-based ceramics are a type of oxynitride ceramics, which can be used as cutting tools for heat-resistant super alloys (HRSAs). These ceramics are derived from Si3N4 ceramics. SiAlON can be densified using gas-pressure reactive sintering from mixtures of oxides and nitrides. In this study, we prepare an α-/β-SiAlON ceramic composite with a composition of Yb_0.03Y_0.10Si_10.6Al_1.4O_1.0N_15.0. The structure and mechanical/thermal properties of the densified SiAlON specimen are characterized and compared with those of a commercial SiAlON cutting tool. By observing the crystallographic structures and microstructures, the constituent phases of each SiAlON ceramic, such as α-SiAlON, β-SiAlON, and intergranular phases, are identified. By evaluating the mechanical and thermal properties, the contribution of the constituent phases to these properties is discussed as well.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 1997.04a
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• pp.34-34
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• 1997

The effect of alloying mode and porosity on the axial tension-tension fatigue behavior of a P/M steel of nominal composition Fe-4w/o Ni-1.5w/o Cu-O.5w/o Mo-O.5w/o C has been evaluated. Alloying modes utilized were elemental powder mixing, partial alloying(distaloy) and prealloying by water atomization; in each case the carbon was introduced as graphite prior to sintering. Powder compacts were sintered($1120{\circ}C$/30 min.) in 7Sv/o $H_2$/25v/o $N_2$ to densities in the range 6.77-7.2 g/$cm^3$. The dependence of fatigue limit response on alloying mode and porosity was interpreted in terms of the constituent phases and the pore and fracture morphologies associated with the three alloying modes. For the same nominal composition, the three alloying modes resulted in different sintered microstructures. In the elemental mix alloy and the distaloy, the major constituent was coarse and fine pearlite, with regions of Ni-rich ferrite, Ni-rich martensite and Ni-rich areas. In contrast, the prealloy consisted primarily of martensite by with some Ni-rich areas. From an examination of the fracture surfaces following fatigue testing it was concluded that essentially all of the fracture surfaces exhibited dimpled rupture, characteristic of tensile overload. Thus, the extent of growth of any fatigue cracks prior to overload was small. The stress amplitude for the three alloying modes at 2x$l0^6$ was used for the comparison of fatigue strengths. For load cycles <3x$l0^5$, the prealloy exhibited optimum fatigue response followed by the distaloy and elemental mix alloy, respectively. At load cycles >2x$l0^6$, similar fatigue limits were exhibited by the three alloys. It was concluded that fatigue cracks propagate primarily through pores, rather than through the constituent phases of the microstructure. A decrease in pore SIze improved the S-N behavior of the sintered steel.

• Journal of the Korean Society of Safety
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• v.32 no.5
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• pp.54-61
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• 2017

The purpose of this study is to develop standard reference materials for safety control of construction materials considering the required performance of standard materials including flow performance incorporating particles. The flow characteristics of concrete are very complicated depending on mixing proportions of constituent materials, admixtures, amount of mixing, type of mixer, time of mixing, temperature and so forth. Uncertainties and multidimensional properties of concrete have been evaluated through various studies but there are few researches for the development of standard reference material. In this study, based on the rheological concept, the flow performance of construction materials was evaluated to understand the properties of standard reference materials and was finally obtained representing materials which simulate the standard reference materials.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.5-9
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• 2003

Stress and deflection of Active Fiber Composite(AFC) embedded and/or attached composite structures are numerically investigated at the constituent level by the Direct Numerical Simulation(DNS). The DNS approach which models and simulates the fiber and matrix directly using 3D finite elements need to be solved by efficient way. To handle this large scale problem, parallel program for solving piezoelectric behavior was developed and run on the parallel computing environment. Also, the stress result from DNS approach is compared with that from uniform field model.

• Korean Journal of Metals and Materials
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• v.47 no.1
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• pp.7-12
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• 2009

The detailed quantitative microstructural data on the cracking of coarse constituent particles in 7075 (T651) series wrought Al-alloys have been studied using the utility of a novel digital image processing technique, where the particle cracks are generated due to monotonic loading. The microstructural parameters such as number density, volume fraction, size distribution, first nearest neighbor distribution, and two-point correlation function have been quantitatively characterized using the developed technique and such data are very useful to verify and study the theoretical models for the damage evolution and fracture of Al-alloys. The data suggests useful relationships for damage modeling such as a linear relationship between particle cracking and strain exists for the uniaxial tensile loading condition, where the larger particles crack preferentially.

• Journal of Environmental Science International
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• v.12 no.9
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• pp.897-903
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• 2003

This study focuses on importance level analysis of environmentally-friendly planning factors using Analytic Hierarchy Process(AMP). This study verify different planning principle makes comparison matrix by a relative comparison value, verified consistency after yield weight to analyze more objective importance for apartment complex estate environmentally-friendly planning factor. In order to decide importance of apartment complex estate environmentally-friendly planning factors multiplying weight of verified planning principle with weight of planning factors. The results are as follows; First, importance of preservation of green tract of lands, Preparation of Biotop, Tree planting of sites, Propriety of development density high except Circulation and practical use of water. Next, valued planning factors constituent appeared to Energy efficient building plan, Rubbish recycling, thermal utilization of solar energy, Artificial tree planting of buildings etc. importantly. Finally, plan constituent that importance is underrated most appeared by Practical use of building materials and equipment, Centralization of energy and resources, Preservation of corridor etc.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.597-598
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• 2006

Gas filtration at high temperature from industrial processes offers various advantages such as increasing process efficiency, improving heat recovery and materials resource recovery, etc. At the same time, it is an advanced environment protection technology. This paper describes a newly developed metallic filter element. The manufacturing process of sintered $Fe_3Al$ metallic powder and the mechanical and filtration characteristics of this filter element were investigated. In this work, the phase constituent changes of the $Fe_3Al$ powder during sintering were studied. The newly developed filter elements were found to have excellent corrosion resistance, good thermal resistance, high strength and high filtration efficiency.

• Journal of Gifted/Talented Education
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• v.18 no.3
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• pp.591-612
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• 2008

In order to investigate the composition and characteristics of instructional objectives in a teaching-learning material for gifted elementary students in science, 217 instructional objectives across 13 themes in 4 areas of 'energy','materials', 'life' and 'earth' were analyzed by Bloom's revised taxonomy of educational objectives. Four types of factual, conceptual, procedural and meta-cognitive knowledge in knowledge dimension were all comprised in the objectives. Conceptual knowledge was primary constituent of the objectives and the proportion of factual knowledge was the least. On the other hand, all 6 categories of 'remember', 'understand', 'apply', 'analyze', 'evaluate' and 'create' in cognitive process dimension were also comprised in the objectives. The category of 'understand' was primary constituent and that of 'remember' was the least one. While conceptual knowledge in knowledge dimension was primary constituent of the objectives in 'energy', 'materials' and 'earth' areas, procedural knowledge was the most objectives in 'life' area. The least type of knowledge was factual knowledge in all 4 areas. In cognitive process dimension, the category of 'understand' was primary constituent and that of 'remember' was the least one in all 4 areas. In conclusion, it was showed that the instructional objectives in the teaching-learning material reflected the characteristics of educational objectives for gifted students in science.