• Title/Summary/Keyword: pore analysis

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Study on the Removal Efficiency of a TEDA Impregnated Charcoal Bed for Methyliodide under Dry Condition (건조 조건하에서 TEDA주입 탄소층에 의한 Methyliodide 제거 효율에 관한 연구)

  • Won Jim Cho;Soon Heung Chang
    • Nuclear Engineering and Technology
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    • v.16 no.2
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    • pp.80-88
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    • 1984
  • The removal mechanism of air borne methyl iodide by triethylenediamine (TEDA) impregnated charcoal bed was investigated. The analysis of experimental data indicates that pore diffusion is the rate controlling step when the air velocity is over 20cm/sec, and both fore diffusion resistance and external mass transfer resistance are contributed to the overall resistance when the air velocity is 10cm/sec. The adsorption model to describe the performance of impregnated charcoal bed under dry condition where water vapors do not exist in air, is proposed. The calculated values and experimental results are well matched.

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탄.소성 Work-Hardening 모델에 대한 Program 개발 -Lade 모델을 중심으로-

  • 박병기;정진섭
    • Proceedings of the Korean Geotechical Society Conference
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    • 1991.10a
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    • pp.255-270
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    • 1991
  • In recent years. finite element methods have been used with increasing effectiveness in analysis of displacements and stresses within soil masses. However, one of the weakest links in the analytical representations used in these methods is the models of the material behaviour. Herein is discribed a modification to the finite element methods that allows solution problems with realistic stress-strain relation for soils. A finite element program for the precision prediction of the stress distribution within foundation has been developed using the elasto-plastic Work-Hardening model. The developed program is verified by comparing the results of this study with the tested results for Sacramento river sand. The main results obtained from the numerical examples are as follows: The vertical total stress increments are insensitive to drainage and constitutive equation of materials. The horizontal total stress increments are considerably affected by the drainage and constitutive equation of materials. The maximum shear stresses are affected by the drainage only in elasto-ptastic meterirals. The excess pore water pressures and the volumetric strains not only are considerably affected by the constitutive equation of materials. but also have almost similar distribution.

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Impedance Spectroscopy Analysis of Hydration in Ordinary Portland Cements Involving Chemical Mechanical Planarization Slurry

  • Hwang, Jin-Ha
    • Journal of the Korean Ceramic Society
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    • v.49 no.3
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    • pp.260-265
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    • 2012
  • Impedance spectroscopy was used to monitor the hydration in the electrical/dielectric behaviors of chemical mechanical planarization (CMP)-blended cement mixtures. The electrical responses were analyzed using their equivalent circuit models, leading to the separation of the bulk and electrode based responses. The role of the CMP slurry was monitored as a function of the relative compositions of the CMP-blended cements, i.e. water, CMP slurry, and ordinary Portland cement. The presence of $Al_2O_3$ nanocrystals in the CMP slurries appeared to accelerate the hydration process, along with a more tortuous microstructure in the hydration, with enhanced hydration products. The frequency-dependent impedance spectroscopy was proven to be a highly efficient approach for evaluating the electrical/dielectric monitoring of the change in the pore structure evolution that occurs in CMP-blended cements.

Theoretical approach for ground behaviour during tunnelling in soils (토사터널굴진시 지반거동에 대한 이론적 접근에 대한 연구)

  • Kim, Sang-Hwan
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.5 no.4
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    • pp.301-312
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    • 2003
  • This paper considers the stresses and pore pressures induced in soft ground due to tunnelling and it presents and discusses the approach methods for estimating the stability of the tunnel and its heading during drained and undrained condition. In practical, the undrained analyses of the face stability of shield tunnelling in soft soil, are carried out based on the field data measured during tunnelling and the results are also evaluated.

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A study on material selection for semiconductor die parts and on their modification and manufacture (반도체금형에서 부속부품의 재료선정 및 개선과 제작에 관한 연구)

  • Kim, Sei-hwan;Choi, Kye-kwang
    • Design & Manufacturing
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    • v.8 no.1
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    • pp.27-30
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    • 2014
  • Alloy tool steel such as SKD11 and SKD61 or high speed tool like SKH51 are used as materials for semiconductor dies. Cavities, curl blocks, pot blocks and housings are made from those materials. To make those parts from alloy tool steel or high speed tool, one utilizes discharge machining, and mechanical machining including machining center, milling, drilling, forming grinding and others. In the process of cutting machining and polishing, the die materials become unsuitable for machining owing to bubbles and foreign substances in them, which hinders production process. Therefore, this study focuses on die material selection criteria, and on analysis and comparison of material characteristics to help companies to solve their problems, make die manufacture less burdensome and extend die life.

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Preparation and Characterization of Carbonized Material from Al-Fe-Mg-Si Nanocomposites Impregnated Biomass

  • Kim, Jin Woo;Lee, Chul Jae
    • International Journal of Advanced Culture Technology
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    • v.6 no.2
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    • pp.129-136
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    • 2018
  • Our present study, we impregnated Al-Fe-Mg-Si (NFM) nanocomposites having various concentrations 0, 1000, 3000, and 5000 mg/L in biomass in order to make carbonized biomass. We characterized the properties of the impregnated samples through thermogravimetric/differential thermal analysis (TG-DTA), pore distribution, scanning electron microscopy (SEM). The best results were observed for a NFM nanocomposites concentration of 5000 mg/L. After the first heat treatment, carbonization, and activation processes, the fixed carbon ratio and iodine adsorptivity were increased by 21.89% and 368 mg/g, 23.98% and 475 mg/g, 26.40% and 238 mg/g, respectively. The remove rate of malodorous and VOCs were that the sample shows good removal capabilities. From above results, our sample could be used for the removal of noxious and malodorous gases and for the purification of wastewater.

The Influence of Fabrication Parameters on the Porosity Formation during Squeeze Infiltration Process (가압함침공정 중 기공 형성에 대한 제조 변수의 영향)

  • 서영호;이형국
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2001.05a
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    • pp.184-188
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    • 2001
  • The squeeze infiltration process is potentially of considerable industrial importance. The performance enhancements resulting from incorporation of short alumina fiber into aluminum are well documented. These are particularly significant for certain automobile components. But the solidification process gets complicated with manufacturing parameters and factors for porosity formation do not fully understand yet. In this study porosity defects were observed under several infiltrating conditions ; a kind of matrix, an initial temperature of melt, and a volume fraction of reinforcement. The desimetry and the microscopic image analysis were done to measure the amount of porosity. A correlation between manufacturing parameters and defects was investigated through these.

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Correlation of the Green Microstructure of ZrO2 with the Colloid/Interface Variables (Zirconia성형체의 미세구조와 콜로이드/계면변수와의 상관관계에 대한 분석)

  • 장현명;한규호;이기강;정한남
    • Journal of the Korean Ceramic Society
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    • v.27 no.1
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    • pp.91-101
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    • 1990
  • The green microstructure and sintering behavior of ZrO2 were analyzed in terms of kinetic stability (measured by the stability ratio ; W) and interfacial characteristics of colloidal suspension. Green density and the most frequent pore radius(MFPR) of green body were directly correlated with the stability ratio. These observations were explained using a concept of the critical stability ratio(Wc) and the potential energy of two interacting particles in colloidal suspension. Analysis of the data also indicates that the potential energy barrier between two interacting colloid particles should be higher than its critical value for a fabrication of ZrO2 green body with dense and uniform microstructure. Besides, we have successfully applied a concept of the donoracceptor interaction to increase the kinetic stability of ZrO2 slip and density of green body.

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STRENGTH CHANGES OF SURROUNDING CLAY DUE TO SOIL-CEMENT COLUMN INSTALLATION

  • Miura, Norihiko
    • Proceedings of the Korean Geotechical Society Conference
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    • 1997.10a
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    • pp.19-36
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    • 1997
  • This paper discusses the reduction and subsequent recovery and increase of shear strength of clay in the vicinity of soil-cement column. Laboratory and field tests were conducted to investigate the effects on surrounding clay during and after soil-cement column installation in soft Ariake clay. Discussions were made on the mechanism of strength changes of clay by considering the thixotropic recovery, reconsolidation effect, penetration of cement slurry and diffusion of exchangeable cations. On the basis of field and laboratory observations, 10 days after column installation, the decreased shear strength of surrounding clay during mixing was recovered and 30 days later, shear strength of surrounding clay increased 30% by average. Therefore, it is recommended that the increase of shear strength of clay can be taken into consideration in the bearing capacity and stability analysis of the composite ground.

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Strength Characteristics of Clay Soil by Preconsolidation Pressure (선행하중(先行荷重)에 의한 점토(粘土)의 강도특성(强度特性))

  • Chon, Yong-Baek;Shin, Young-Gi
    • 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.

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