• Journal of Welding and Joining
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• v.15 no.6
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• pp.32-40
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• 1997

Solid state diffusion bonding is the joining process performed by creep and diffusion, which is accelerated by heating below melting temperature and proper pressing, in vacuum or shielding gas atmosphere. By this process we can obtain sufficient joint which can't be expected from the fusion welding. For Ti-6Al-4V alloy, the optimum solid state diffusion bonding condition and mechanical properties of the joint were found, and micro void morphology at bond interface was observed by SEM. The results of tensile test showed sufficient joint, whose mechanical properties are similar to that of base metal. 850$^{\circ}$C, 3MPa is considered as the optimum bonding condition. Void morphology at interface is long and flat at the initial stage. As the percentage of bonded area increases, however, small and round voids are found. Variation of void shape can be explained as follows. As for the void shrinkage mechanism, at the initial stage, power law creep is the dominant, but diffusion mechanism is dominant when the percentage of bonded area is increased.

• Geomechanics and Engineering
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• v.25 no.2
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• pp.159-170
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• 2021

Particle size of tailings in different areas of dams varies due to sedimentation and separation. Saturated hydraulic conductivity of high-stacked talings materials are seriously affected by void ratio and particle breakage. Conjoined consolidation permeability tests were carried out using a self-developed high-stress permeability and consolidation apparatus. The hydraulic conductivity decreases nonlinearly with the increase of consolidation pressure. The seepage pattern of coarse-particle tailings is channel flow, and the seepage pattern of fine-particle tailings is scattered flow. The change rate of hydraulic conductivity of tailings with different particle sizes under high consolidation pressure tends to be identical. A hydraulic conductivity hysteresis is found in coarse-particle tailings. The hydraulic conductivity hysteresis is more obvious when the water head is lower. A new hydraulic conductivity-void ratio equation was derived by introducing the concept of effective void ratio and breakage index. The equation integrated the hydraulic conductivity equation with different particle sizes over a wide range of consolidation pressures.

• Journal of the Korean Society of Industry Convergence
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• v.6 no.3
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• pp.185-192
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• 2003

This study consolidation undrain Triaxial Compression Tests using constant confining pressure in clay that receive preconsolidation stress that is different and, void ratio, pore water pressure coefficient, shear strength compare with another thing theory and studied analyzing change relation of elastic modules. The summary of analysis is follows: If preconsolidation stress increases in same confining stress in relation of preconsolidation stress and deviator stress, deviator stress is proportional and increased. Can know that excess void pressure is proportional and decreases in size of preconsolidation stress in same confining stress state if preconsolidation stress increases preconsolidation stress and relation of excess void pressure. Also, over consolidated state can assume that this is thing by Dilatancy's effect though excess void pressure decreased remarkably. Preconsolidation stress and relation of stress path can know that shear strength degree increases preconsolidation stress increases, and specially, preconsolidation stress was appear in stress path form of overconsolidated state case of clay that receive at 300, 400, 500kPa in 100, 150kPa's deviator stress.

• Nuclear Engineering and Technology
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• v.41 no.3
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• pp.295-306
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• 2009

The subchannel grade void distributions in the NUPEC (Nuclear Power Engineering Corporation) BFBT (BWR Full-Size Fine-Mesh Bundle Tests) facility were evaluated with the subchannel analysis code MATRA and the system code MARS. Fifteen test series from five different test bundles were selected for an analysis of the steady-state subchannel void distributions. Two transient cases, a turbine trip without a bypass as a typical power transient and a re-circulation pump trip as a flow transient, were also chosen for this analysis. It was found that the steady-state void distributions calculated by both the MATRA and MARS codes coincided well with the measured data in the range of thermodynamic qualities from 5% to 25%. The results of the transient calculations were also similar and were highly feasible. However, the computational aspects of the two codes were clearly different.

• Journal of The Korean Society of Agricultural Engineers
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• v.57 no.1
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• pp.11-23
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• 2015

In this study the laboratory test for hydraulic conductivity and the seepage analysis with finite element method on measurement section of sea dike embankment were performed for the purpose of estimating the relative density of embankment from the measured pore water pressures, and both results of the test and the analysis were coupled with the method of estimating seepage blocking state with the hydraulic head loss rate in sea dike embankment. The relationship of void ratio vs hydraulic head loss rate was obtained by setting hydraulic conductivity as common ordinate on the relationships between the void ratio and the hydraulic conductivity and between the hydraulic conductivity and the hydraulic head loss rate. The void ratio on the segment between measuring points was calculated from the coupled relationship of the void ratio vs the hydraulic conductivity. The allowable upper and lower limits of hydraulic head loss rate and those of void ratio on the safety were generated from the coupled relationship between the laboratory compaction test and the sedimentation test. Current hydraulic head loss rate and void ratio were evaluated in the allowable range between upper and lower limits.

• 전기의세계
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• v.16 no.3
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• pp.21-27
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• 1967

We meet with the fact that a majority of electric machinery have been insulated to the state of solids & liquids or solids & gases, that is, with compound dielectrics. And also we can find voids caused by undesirbble structure, long-used material and so on. When it is discharged in a void or in the parts of gases of insulating material, the insulation of the machinery is gradually and finally destroyed through the effect of ozone, nitrogen-oxide, electronic pulses and so on. So we maybe conculded that it is necessary and important to detected void pulse and void corona in order to prevent sudden break down of electric machinery.

• Magazine of the Korean Society of Agricultural Engineers
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• v.44 no.3
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• pp.85-91
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• 2002

This study is performed to evaluate characteristics of plantable concrete using waste stone and stone dust. The test result shows that the void ratio is decreased as the size of waste stone smaller and the content of stone dust increased. The strength of neutralized plantable concrete is decreased by approximately 4∼5% than that of the normal plantable concrete. The reduction effect of pH value is achieved by chemical treatment. Also, the plant is grown well with increase of the void ratio and size of waste stone.

• Journal of The Korean Society of Agricultural Engineers
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• v.47 no.4
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• pp.35-41
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• 2005

In order to analyse the flow problems for an unsaturated soil, it is required to examine closely the characteristics of the coefficient of permeability which is changing with the matric suction. To this ends, a permeability test was conducted on the three samples;granular soil, cohesive soil and silty soil. The specimen was made by pressing the static pressure on the mold filled with soil and the void ratio was controled with the different compaction ratio. And the test was performed by using the modified apparatus of the steady state method which was proposed by flute (1972). The range of matric suction was 0-90 kPa. The measured results for the coefficients of permeability were analysed with the void ratio and the compaction ratio, and it was examined closely the characteristics of the permeability for an unsaturated soil.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.5-8
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• 2005

Sound absorbing performance is affected by porosity and continuity of void, therefore it is important to maintain stabilization of foam and to analyze properties of void pore in hardened state. The purpose of this study is to analyze the sound absorption properties and void characteristic of foamed concrete according to dilution ratio of foaming agent. The results of this experiment were as follows. It is determined that an increase in total and continuous void ratio is achieved by increasing of dilution ratio, and a shorter absorbing time was exhibited at a higher continuous void ratio. When the average void size of foamed concrete was below 1.5mm, the tendency of sound absorption coefficient compared with general sound absorber was appeared similarly.

• Nuclear Engineering and Technology
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• v.16 no.4
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• pp.195-201
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• 1984

A state-of-the-art mechanistic model has been developed to accurately predict the void fraction in the subcooled boiling region having axial nonuniform heat flux. In this study, the void-dependent drift-flux parameters of the Lahey/Ohkawa model were introduced and the mass flux-dependent condensation coefficient were determined by fitting with the experimental data. This model was tested against several experimental data sets to verify its accuracy. Finally the comparison between the predicted void fraction profiles with this model and the profile-fit model for the hot assembly of Kori-Unit 1, Cycle 1 has been performed. It is conclusive that the results show the good agreement between the measured and predicted void fractions, and the profile-fit model has been found to underestimate the void fraction in the subcooled boiling region.