• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.35 no.2
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• pp.172-177
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• 2022

The quench voltage of the second-generation superconducting wire is affected by the resistivity characteristics of the stabilization layer. The specific resistance of the stabilization layer can be changed by the deposition process using RF magnetron sputtering. In this paper, a thin film made of a homogeneous material (Ag) and a dissimilar material (Cu) was deposited on the stabilization layer of the second-generation superconducting wire through RF magnetron sputtering. We found that the specific resistance was reduced by increasing the thickness of the stabilization layer. The reduction in the resistivity of the stabilization layer led to a decrease in the quench voltage of the second-generation superconducting wire. We suggest that various characteristic changes of the second-generation superconducting wire can be expected through the successful change in the resistivity of the stabilization layer of the proposed deposition process.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.03a
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• pp.731-738
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• 2002

Recently, as large constructions on the coast are performed frequently, surface layer stabilization method which Is one of the improvement methods for dredged soft clay has been applied. However, there have been few studies about the surface layer stabilization method. The purpose of this study is to clarify characteristics of ultra-soft marine clay and hardening agent. Also, optimal mixture ratio of hardening agent was verified through the laboratory tests such as statistical analysis and pilot tests. Laboratory tests were performed with proper hardening agent and test soil and standard mixing tables of hardening agent were determined according to ground conditions through statistical analysis. Also, applicability of surface layer stabilization method to field was verified by pilot tests. From the results of the tests, it was found that hardening agent materials such as cement, slag, fly-ash, inorganic salts, arwin, gypsum etc. affect on the appearing compressive strength. It was defined optimal mixture ratio which satisfies the required compressive strength from the statistical analysis. Also, It was compared the effect of ground improvement by cements and hardening agents through the pilot tests. This study will serve as data for design or construction criteria of stabilization of surface layer on ultra-soft marine clay.

• Geomechanics and Engineering
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• v.12 no.2
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• pp.257-267
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• 2017

This paper presents laboratory investigation of stabilization of subgrade soil. One type of soil and three types of stabilizers i.e., hydrated lime, class F fly ash and polypropylene fibres are selected in the study. Atterberg limit, compaction, california bearing ratio (CBR), unconfined compressive strength and triaxial shear strength tests are conducted on unstabilized and stabilized soil for varying percentage of stabilizers to analyze the effect of stabilizers on the properties of soil. Vertical compressive strains at the top of unstabilized and stabilized subgrade soil were found out by elasto-plastic finite element analysis using commercial software ANSYS. Strategy for design of optimum pavement section was based on extension in service life (TBR) and reduction in layer thickness (LTR). Extension in service life of stabilized subgrade soil is 6.49, 4.37 and 3.26 times more due to lime, fly ash and fibre stabilization respectively. For a given service life of the pavement, there is considerable reduction in layer thicknesses due to stabilization. It helps in reduction in construction cost of pavement and saving in natural resources as well.

• Advances in Computational Design
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• v.3 no.2
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• pp.201-212
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• 2018

Decrease in availability of suitable subbase and base course materials for highway construction leads to a search for economic method of converting locally available troublesome soil to suitable one for highway construction. Present study insights on evaluation of benefits of stabilization of subgrade soils in term of extension in service life (TBR) and layer thickness reduction (LTR). Laboratory investigation consisting of Atterberg limit, Compaction, California Bearing Ratio, unconfined compressive strength and triaxial shear strength tests were carried out on two types of soil for varying percentages of stabilizers. Vertical compressive strains at the top of unstabilized and stabilized subgrade soils were found out by elastoplastic finite element analysis using commercial software ANSYS. The values of vertical compressive strains at the top of unstabilized and stabilized subgrade, were further used to estimate layer thickness reduction or extension in service life of the pavement due to stabilization. Finite element modeling of the flexible pavement layered structure provides modern technology and sophisticated characterization of materials that can be accommodated in the analysis and enhances the reliability for the prediction of pavement response for improved design methodology. If the pavement section is kept same for unstabilized and stabilized subgrade soils, pavement resting on lime, fly ash and fiber stabilized subgrade soil B will have service life 2.84, 1.84 and 1.67 times than that of unstabilized pavement respectively. The flexible pavement resting on stabilized subgrade is beneficial in reducing the construction material. Actual savings would depend on the option exercised by the designer for reducing the thickness of an individual layer.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.7
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• pp.527-534
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• 2009

Flame stabilization characteristics were experimentally investigated in a fuel-air cross flowing mixing layer. A combustor consists of a narrow channel of air steam and a cross flowing fuel. Depending on the flow rates of methane and air, flame can be stabilized in two modes. First is an attached flame which is formulated at the backward step where the methane and air streams meet. Second is a lifted-flame which is formulated within the mixing layer far down steam from backward step. The heights and flame widths of the lifted flames were measured. Flame shapes of the lifted flames were similar to an ordinary edge flame or a tribrachial flame, and their behavior could be explained with the theories of an edge flame. With the increase of the mixing time between fuel and air, the fuel concentration gradient decreases and the flame propagation velocity increases. Thus the flame is stabilized where the flow velocity is matched to the flame propagation velocity in spite of a significant disturbance in the fuel mixing and heat loss within the channel. This study provides many experimental results for a higher fuel concentration gradient, and it can also be helpful for the development and application of a smaller combustor.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.211-211
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• 2009

YBCO coated conductor can change the stabilization layer for purpose and it leads advantages in Improvement of tape's critical properties and Application. Such properties rise possibility of using YBCO coated conductor for Superconductor Fault Current Limiter, therefore, we investigate changing properties under over current condition and limiting characteristics. In this study, YBCO coated conductor's current limiting characteristic stainless steel stabilization layer under condition of changing conductor's insulating layer. Consequently, the resistance followed insulating layer so we know that limiting characteristics.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.3B
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• pp.325-335
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• 2010

The aim of this study is to survey the effects of laying drainage layer in sandy beach on beach stabilization. At first, the numerical model developed by Hur and Lee (2007), which is able to consider the flow through a porous medium with inertia, laminar and turbulent resistance terms, i.e. simulate directly WAve Structure Seabed/Sandy beach interaction and can determine the eddy viscosity with LES turbulent model in 3-D wave field (LES-WASS-3D), is validated by comparing with existing experimental data. And then, numerical simulation is carried out to examine the characteristics of wave-sandy beach interaction for a beach with/without drainage layer. From the numerical results, it is shown that mean ground-water level around a foreshore decreases and offshore-ward flow over a seabed reduces in case of a beach with drainage layer. Moreover, the effects of cross profile of drainage layer and incident wave condition on mean ground-water level around a foreshore are also discussed as well the distribution of wave setup around the foreshore.

• Journal of the Korean Society of Combustion
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• v.15 no.3
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• pp.1-7
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• 2010

Edge flames have been interested as a basic structure that is concerned to flame stabilization and re-ignition of non-premixed flames. The edge flame consists of a lean premixed flame, a rich premixed flame, and a diffusion flame. In order to investigate fundamental structures of the edge flames at the conditions near the flammability limits, edge flames were stabilized within a heated narrow channel. Highly diluted partially premixed methane was used, and the flow rates of air and the partially premixed mixture were controlled. Various flame behaviors, including a transition between ordinary edge flames and premixed flames, were observed. Flame stabilization characteristics were examined as well. All flame stabilization conditions in this study showed a similar trend: characteristic time scales were inversely proportional to the equivalence ratio defined at the burner inlet. Finally, an interesting flame structure having a weak diffusion branch enveloped by a closed premixed branch was found near the flammability limits even in a fuel-air mixing layer. This structure was named as a "flame-drop" and the importance of this structure was first suggested.

• Journal of the Korean Geotechnical Society
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• v.18 no.4
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• pp.33-43
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• 2002

Recently, as large constructions on the coast increase, an application of a surface layer stabilization method which is one of the improvement methods for dredged soft clay has increased. However, there are few studies about this. The purpose of this study is clarifying characteristics of ultra-soft marine clay and hardening agent. Also, it is verifying an optimal mixture ratio of hardening agent through the laboratory tests according to designed experiments and proving by statistical analysis and pilot tests. Laboratory tests were performed with proper hardening agent and test soil in accordance with the design of experiments. Regression equations between hardening agents materials and unconfined compressive strength were derived from the tests. The applicability of regression equations were also verified by pilot tests. From the test results, it was found that hardening agent materials(cement, slag, fly-ash, inorganic salts, arwin, gypsum etc.) have some effect upon compressive strength. The optimal mixture ratio which satisfies the required compressive strength was derived from the statistical analysis. The effect of ground improvement by cements and hardening agents was confirmed through the pilot tests. This study will suggest data for design or construction criteria of stabilization of surface layer on ultra-soft marine clay.

• Magazine of the Korean Society of Agricultural Engineers
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• v.9 no.2
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• pp.1306-1310
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• 1967