• IE interfaces
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• v.19 no.2
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• pp.117-123
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• 2006

Many products, such as gasoline, polymer plastics, alloys, and ceramics are manufactured by mixing two or more ingredients or components. When we are to develop new mixture products, we must deal with a long list of potentially important component variables. This paper introduces some mixture screening designs, analysis tools for screening important variables, and a guideline for applying these analysis tools. The results of this paper will be helpful to engineers who work in the research and development sector of mixture product industries.

• Land and Housing Review
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• v.10 no.4
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• pp.51-59
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• 2019

The government is encouraging the notice of obligatory reclaimed asphalt as a result of the economic and social positioning of green growth to reduce the amount of waste resources and to solve natural resource problems by recycling continuously generated waste resources. However, it is necessary to develop application guideline for each application to apply reclaimed asphalt to the site because quality control of the reclaimed asphalt is difficult and the specifications are ambiguous as well. Therefore, in this study, the mix design, quality test, performance test, and finite element analysis about reclaimed Asphalt Pavement were conducted to develop application guideline for reclaimed hot asphalt. The mix design was carried out for the comparative general hot mix asphalt mixture, the reclaimed hot mix asphalt mixture using the additive, and the reclaimed hot mix asphalt mixture without the additive. Indirect tensile strength and tensile strength ratio tests were used to characterize the reclaimed hot mix asphalt mixture. Using the results of dynamic modulus test and FWD test for KPRP analysis and finite element analysis, the performance life was evaluated for general pavement and pavement using recycled aggregate. Finally, the life cycle cost analysis was used to compare and analyze the economics of reclaimed asphalt concrete pavement.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.12
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• pp.3326-3334
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• 1994

To theoretically predict knock occurrence in S. I. engine as a function of engine design and operating parameters, transient local temperature and pressure, mixture density of flame front in combustion period are calculated. We next determined normal combustion period and auto ignition period of end gas using the prediction method on occurrence of spark knock which we suggested. We predict knock occurrence in S. I. engine by comparing consecutively normal combustion period with the auto ignition period of end gas in combustion period. Engine design and operating parameters such as compression ratio, engine speed, spark timing, inlet temperature and pressure are taken into account in this calculations. The predicted result are well matched with the experimental results in turbocharged engine. Therefore, this method will provide the systematic guideline for designing engines in view of knocking limits.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.5
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• pp.482-488
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• 2009

Dancer system is typically used equipment for attenuation of tension disturbances. In industrial converting machines, a composite type of dancer system is applied which is mixture of active and passive dancer. It includes feedback position control loop of roll with pendulum dancer and its characteristics is different from passive and active one. In this paper, a mathematical model of the pendulum dancer was derived including PI position feedback controller and it was analyzed by using a pole-zero map and bode plot under various conditions. It was found out that velocity, length of span and inertia were associated with the performance of regulation. It was suggested that the length of upstream span should be greater than that of the downstream and the inertia should be smaller for improvement of the performance. The results can be used for design guidelines of the industrial dancer system.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.517-520
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• 2004

Concrete Filled steel Tube pipe structure is a rational type of structure that maximizes performance by combining the strong points of steel frame and concrete. In the structure, the confining effect of steel pipes increases the bearing power of infilled concrete and the strengthening of local bucking of steel pipes by infilled concrete increases the bearing power of members. and these result in the reduction of cross-sectional area and high transformation capacity. Moreover. the structure is economically efficient and widely applicable that it is used from super-high buildings to residential, business and apartment buildings. It enables the construction of multi-story buildings with long spans using columns of small cross-sectional area. In case of diaphragm, however, it is difficult to confirm the compactness of the closed inside of steel pipes. The present study examined the properties of super-high strength concrete over 80MPa by comparing it with 40MPa concrete through heat conductivity and length change tests based on a mixture ratio satisfying the mixture goal presented in the guideline for the design and construction of concrete-filled steel pipe structure. and evaluated the performance of super-high strength concrete according to the shape and size of the aperture ratio of diaphragm.

• Korean Institute of Interior Design Journal
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• no.11
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• pp.31-37
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• 1997

This study intens to provide available guideline of useful plants in interior and be used by designer. It focuses on evaluating the character of plants, the method of installation and the form of composition for suitable design of using plants. The study finds out that using plants in interior are necessary positively by 94% respondents. And results of factor analysis are that plants are needed for emothional stability(factor 1), visual charming(factor 2), and educational effection(factor 3). According to job, the group of students is visual charming (P=0.0037), the public servants and housewives is educational effection(p=0.0029). The most available space of plants as follows : Department(30.5%), Hotell(26.3%), House and Restuarant(12.7%). It has been identified that the public institution and commercial space are much indused plants. The most indused plants in house is ordered that the veranda, the living room, the entrance. This result is concerned about relation of natural light plants. The repondants reply that the favorite arrangement style is the corner form(63%), the center garden form(52.1%), the large planter(19.7%), the planter box(11.3%). They respond that they are more favorite light green color than dark, and mono color than mixture color. Finally, interior Designers should be understood the functional and aesthetic elements and the special interest about plants for developing desigv.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.5
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• pp.19-24
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• 2004

Entrainment of ambient gas into a transient diesel spray is a crucial factor affecting the following preparation of combustible mixture. In this study, the entrainment characteristics of ambient gas for a non-evaporating transient diesel were investigated using a common-rail injection system. The effects of ambient gas density and nozzle hole geometry were assessed with entrainment coefficient. Laser Doppler Velocimetry (LDV) technique was introduced to measure the entrainment speed of ambient gas into a spray. There appeared a region where the entrainment coefficients remained almost constant while injection rates were still changing. The effect of common-rail pressure, which altered the slope of injection rate curve, was hardly noticed at this region. Entrainment coefficient increased with ambient gas density, that is, the effect of ambient gas density was greater than that of turbulent jet whose entrainment coefficient remained constant. The non-dimensional distance was defined to reflect the effect of nozzle hole diameter and ambient gas density together. The mean value of entrainment coefficient was found to increase with non-dimensional distance from the nozzle tip, which would be suggested as the guideline for the nozzle design.

• Journal of the Korean Institute of Landscape Architecture
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• v.52 no.5
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• pp.53-64
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• 2024

This paper is a basic study on replacing ordinary aggregates with zeolite aggregates with high absorption rates in paving concrete for sidewalks. In order to determine the optimal replacement ratio of coarse and fine zeolite aggregates in paving concrete, absorption performance through absorption and drying tests and mechanical properties through compression, bending, and splitting tensile strength tests were investigated. As a result of the absorption tests, the absorption performance, which can be defined as the difference between absorption rate and drying rate, was 6% for coarse aggregates, which was about 4% higher than that of normal aggregates, and 31% for fine aggregates, which was about 11% higher than that of normal aggregates. In addition, in paving concrete mixed with zeolite aggregates, the absorption rate was up to 4.5%, and the drying rate was at least 0.72%, which showed a relatively high absorption performance considering the unit volume weight. The compressive strength of paving concrete mixed with zeolite aggregate decreased at some replacement ratios compared to that of normal aggregate, but all satisfied the design compressive strengths specified in the Korean design standard. The flexural strength also decreased by up to 16% depending on the replacement ratio and was lower than the design flexural strength specified in the mixture design guidelines. However, it was judged that there would be no problem in applying it to concrete pavement for sidewalks with small design loads. The splitting tensile strength, which is important for crack resistance, was the same or decreased at a rate of 6% or less depending on the replacement ratio, so it is considered to be suitable for paving concrete for sidewalks. From the research results on absorption performance and mechanical properties, it was confirmed that zeolite aggregates can be applied to absorbent paving concrete for sidewalks, and the optimal replacement ratio for this was determined to be 20% coarse aggregate and 10% fine aggregate based on a total of 30% replacement.

• Journal of the Korean Recycled Construction Resources Institute
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• v.6 no.2
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• pp.112-118
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• 2011

The recycled asphalt concrete has gotten increasing attention due to the environmental issues. The volume of reclaimed asphalt has increased significantly for last few years because of city remodeling, pavement maintenance, utility excavation, and road widening. Considering the value of reclaimed asphalt, it is rather used for the recycled asphalt concrete than it is used for fill and cover up material instead of soil. This research will be a supplements incomplete issues from existing research results and suggests the quality control guideline for recycled asphalt concrete and upcoming laws. As the first step of research, the trial construction of RAP(Recycled Asphalt Pavement) performed in expressway construction sites. These trial construction sites have been checked every years. And another construction sites studied and selected for more deeper performance check of RAP. For this checks, we used automatic pavement survey equipment and computerized analysis tools. Also, DSR(Dynamic Shear Rheometer) was used for the fatigue life calculation of binder blends(RAP and virgin binder). As a consequence of this research, the application of recycled asphalt provides good enough quality for highway construction. The preceeding literatures reviewed shows that the asphalt rejuvenator are used in many countries but that type of chemical agent are not used in Korea. By using the data of trial construction and mix design in Chongwon-Sangju construction lane, the surface and base courses consisted with the 10% and 30% rap mix asphalt section maintains good performance for up to 7 years. Through the performance check and laboratory tests(DSR), the quality control and mixture's low temperature prevention are the important factor and chemical agent necessary for increasing the fatigue life of RAP binder.