• Journal of the Korean Recycled Construction Resources Institute
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• 제11권4호
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• pp.341-348
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• 2023

In this study, in order to minimize the increase in the amount of various industrial by-products due to the rapid growth of the industry and the intensification of the depletion of natural aggregate resources, the material test using recycled aggregate and steelmaking slag and the proper mixing ratio of recycled concrete were to be derived. In this study, first, the conformity of the quality standards of the materials used in the field was confirmed, and the workability and molding results were shown when used alone or mixed. Therefore, the feasibility of application as aggregate for concrete was evaluated through a total of 4-type mixtures of cement types, admixtures, coarse aggregates, and fine aggregates. As a result of the experiment, it was confirmed that the slump of unhardened concrete, the amount of air, chloride and compressive strength of hardened concrete according to the replacement rate were different from the measured values of general concrete quality characteristics. According to this, it was confirmed that the quality characteristics of the standard design criteria were satisfied.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• 제11권1호
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• pp.11-21
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• 2013

The Geyoungju Ca-bentonite with dry density of 1.6 g/$cm^3$ has been considered as a standard buffer material for the disposal of high level waste in KAERI disposal system design. But it had relatively lower thermal conductivity compared with other surrounding materials, that was one of key parameters to limit the increase of the disposal density in the disposal system. In this study, various additives were selected and mixed with the Ca-bentonite in different mixing methods in order to increase the thermal conductivity from 0.8 W/mK to 1.0 W/mK. As an additive, CNT (Cabon Nano Tube), graphite, alumina, CuO, and $Fe_2O_3$ were selected, which are chemically stable and have good thermal conductivity. As mixing methods, dry hand-mixer mixing, wet milling and dry ball mill mixing were applied for the mixing. Above all, the ball mill mixing was proved to be most effective since the produced mixture was most homogeneous and showed higher increase in the thermal conductivity. From this study, it was confirmed that the thermal conductivity for the Geyoungju Ca-bentonite could be improved by adding small amount of highly thermal conductive material to 1.0 W/mk. In conclusion, it was believed that the experimental results will be valuable in the disposal system design if the additive effects on the swelling and permeability on the compact bentonite are also approved in further studies.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.469-475
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• 2003

The performance of a centrifugal compressor composed of an impeller, tandem diffuser rows and axial guide vanes has been predicted numerically and compared with available experimental results on its design rotational speed. The pitchwise-averaged mixing plane method was employed for the boundaries between rotor and stator to obtain steady state solutions. The overall characteristics showed differently according to the relative positions of tandem diffuser rows while the characteristics of impeller showed almost identical. The numerical results agree with the measured data in respect of their tendency. It turned out that 0% of relative positions is the worst case in terms of static pressure recovery and efficiency. According to the experimental results, some pressure fluctuations and malfunction of the compressor were observed for 75% case. However, this numerical calculation using mixing plane method did not capture any of those phenomena. Thus, unsteady flow calculation should be performed to investigate the stability of the compressor caused by different diffuser configuration.

• Journal of Korean Society for Quality Management
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• 제42권4호
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• pp.579-590
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• 2014

Purpose: Ball milling is a popular process for obtaining fine powders in the part and material industry. One of important issues in the ball milling is to produce particles with a uniform size. Although many factors affect uniformity of particles, this paper focuses on the choice of ball diameter. Consider a ball milling where balls can be taken with three different diameters. The purpose of this paper is to find a ball mix which minimizes the average particle size. Methods: Ball diameters are selected as 10mm, 3mm, and 0.5mm. In order to find an optimum mixing ratio, the method of mixture experiments is employed in this paper. Taguchi's signal-to-noise ratio (SNR) for smaller-the-better type is also used to analyze experimental data. Results: According to the experimental result, SNR is maximized when the ball mix is taken as either 7:3:0 or 6:4:0. Such mixing ratios can be technically validated in terms of porosity reduction. Conclusion: The ball mixing technique presented in this paper provides a useful way to improve the production efficiency with a low cost.

• Proceedings of the KSME Conference
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• 대한기계학회 2002년도 학술대회지
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• pp.155-158
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• 2002

In general, TVC(Thermal Vapor Compressor) is used to boost/compress a low pressure vapor to a higher pressure for further utilization. The one-dimensional method is simple and reasonably accurate, but cannot realize the detail as like the back flow and recirculation in the mixing chamber, viscous shear effect, and etc. In this study, the axisymmetric How simulations have been performed to reveal the detailed flow characteristics for the various ejector shapes. The Navier-Stokes and energy equations are solved together with the continuity equation In the compressible flow fields. The standard $k-{\epsilon}$ model is selected for the turbulence modeling. The commercial computational fluid dynamic code FLUENT software is used for the simulation. The results contain the entrainment ratio under the various motive, suction and discharge pressure conditions. The numerical results are compared with the experimental data, and the comparison shows the good agreement. The three different flow regimes (double chocking, single chocking and back flow) have been clearly distinguished according to each boundary pressure values. Also the effects of the various shape variables (nozzle position, nozzle outlet diameter, mixing tube diameter, mixing tube converging angle, and etc.) are quantitatively discussed.

• Journal of the Korean Society of Clothing and Textiles
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• 제38권3호
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• pp.347-354
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• 2014

The color appearance of a yarn-dyed woven fabric depends on the color of the yarn as well as on the weave structure. Predicting the final color appearance or formulating the recipe is a difficult task, considering the interference of colored yarns and structure variations. In a modern fabric design process, the intended color appearance is attained through a digital color methodology based on numerous color data and color mixing recipes (i.e., color prediction models, accumulated in CAD systems). For successful color reproduction, accurate color prediction models should be devised and equipped for the systems. In this study, the final colors of yarn-dyed woven fabrics were predicted using six geometric-color mixing models (i.e., simple K/S model, log K/S model, D-G model, S-N model, modified S-N model, and W-O model). The color differences between the measured and the predicted colors were calculated to evaluate the accuracy of various color models used for different weave structures. The log K/S model, D-G model, and W-O model were found to be more accurate in color prediction of the woven fabrics used. Among these three models, the W-O model was found to be the best one as it gave the least color difference between the measured and the predicted colors.

• Membrane and Water Treatment
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• 제14권3호
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• pp.129-140
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• 2023

The appropriate injection of H₂O₂ is essential to produce hydroxyl radicals (OH·) by mixing H₂O₂ quickly and exposing the resulting H₂O₂ solution to UV irradiation. This study focused on evaluating mixing device of H₂O₂ as a design factor of UV/H₂O₂ AOP pilot plant using a surface water. The experimental investigation involved both experimental and model-based analyses to evaluate the mixing effect of different devices available for the H₂O₂ injection of a tubular hollow pipe, elliptical type of inline mixer, and nozzle-type injection mixer. Computational fluid dynamics analysis was employed to model and simulate the mixing devices. The results showed that the elliptical type of inline mixer showed the highest uniformity of 95%, followed by the nozzle mixer with 83%, and the hollow pipe with only 18%, after passing through each mixing device. These results indicated that the elliptical type of inline mixer was the most effective in mixing H₂O₂ in a bulk. Regarding the pressure drops between the inlet and outlet of pipe, the elliptical-type inline mixer exhibited the highest pressure drop of 15.8 kPa, which was unfavorable for operation. On the other hand, the nozzle mixer and hollow pipe showed similar pressure drops of 0.4 kPa and 0.3 kPa, respectively. Experimental study showed that the elliptical type of inline and nozzle-type injection mixers worked well for low concentration (less than 5mg/L) of H₂O₂ injection within 10% of the input value, indicating that both mixers were appropriate for required H₂O₂ concentration and mixing intensity of UV/ H₂O₂ AOP process. Additionally, the elliptical-type inline mixer proved to be more stable than the nozzle-type injection mixer when dealing with highly concentrated pollutants entering the UV/H₂O₂ AOP process. It is recommended to use a suitable mixing device to meet the desired range of H₂O₂ concentration in AOP process.

• Proceedings of the KIEE Conference
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.81-83
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• 2006

This Paper suggests efficient design method which is used by Bit_Inerleaver in the IEEE 802.15,3.a. Bit_Interleaver is consist of Symbol_Interleaver and Tone_Interleaver Each Interleaver is designed by using memory. In other to resolve burst error, Block Interleaver is using different leading and writing address for mixing the data. However This method has a different reading and writing memory address to realize Block Interleaver so this schematic is some complex. This Paper suggests efficient and simple Bit_Interleaver Method which classify the memory of Bit_Interleavr to reduce complexity of shcemeatic.

• Journal of Fashion Business
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• 제12권2호
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• pp.100-116
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• 2008

This study aims to analyze the characteristics of deconstruction-ism expressed in the fashion of Alexander McQueen. The method and contents of this study are as follows. The three large categories for analysis are indeterminacy, decentralization, and intertextuality. The indeterminacy of meaning is divided into unstructured and unorganized factors in fashion, while decentralization can be categorized into cross-gender, subculture, and post-humanism. Lastly, inter-textuality is classified into factors of mixing mode and mixed styles. Materials for analysis were chosen from a total of 616 designs from the website, www.firstview.com, which carries McQueen's collection from 2000 S/S through 2007 F/W. My analysis qualitatively evaluates the frequency of each category and the characteristics of design. The result of this study is as followed. First, the avant-garde facets of inter-textuality are most prominent. In particular, McQueen has introduced retro fashion and ethnic factors of the third world, not to copy them but to create hybrid designs by using pastiches and mixing fashion styles. Moreover, he has enjoyed using two fabrics of different texture in order to inflict a shock and contrast, thus enriching his fashion. Second, the indeterminacy of meaning is the second most frequently shown facet of McQueen's fashion design. McQueen has employed unstructured expression techniques, which dismantle harmony and balance, the basic rule of design, and has presented unorganized images free from basic forms of design. He has made a new attempt to acknowledge clothing as an expressive artwork by allowing clothes to take a complete form when a person actually wears them. Third, the aspects of decentralization were also shown in McQueen's design. His trans-gender clothing dissolves the traditional division of men and women and adopts a mixed gender expression. Furthermore, he has even tried to express a fourth gender by connecting the human with machine or animal or by connecting the material with the non-material.

• Korean Institute of Interior Design Journal
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• 제20권2호
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• pp.147-155
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• 2011

The purpose of this study is to grope for plan methods through analyzing preferences on expression methods of materials for visual differentiation in hosing space. The results are as follows : First, we could know that finish material is the important element to make differential design in housing space. It is a effective method to use the color and material of finish materials. Second, we could find they preferred woods in materials and Y color, N9.5, bright and light in colors through grasping preference about types in material elements. The preferred texture is soft and the preferred patterns are solid and geometry. Third, it is a good method to mix materials which give us different season feeling, and to mix colors which are different tones to lead the differential design by materials in housing space. In case texture and patterns, what we mix similar things is the effective method. Fourth, preference of the expression method is manifested differently depending on the selected elements. so when we plan the housing, we have to consider that. lastly, I think this study will be a basic data on a study to differentiate the design of the residential space.