• Title/Summary/Keyword: Isotherm radii

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A Study on Monitoring for Process Parameters Using Isotherm Radii (등온선 반경을 이용한 공정변수 모니터링에 관한 연구)

  • Kim, Ill-Soo;Chon, Kwang-Suk;Son, Joon-Sik;Seo, Joo-Hwan;Kim, Hak-Hyoung;Shim, Ji-Yeon
    • Journal of Welding and Joining
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    • v.24 no.5
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    • pp.37-42
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    • 2006
  • The robotic arc welding is widely employed in the fabrication industry fer increasing productivity and enhancing product quality by its high processing speed, accuracy and repeatability. Basically, the bead geometry plays an important role in determining the mechanical properties of the weld. So that it is very important to select the process variables for obtaining optimal bead geometry. In this paper, the possibilities of the Infrared camera in sensing and control of the bead geometry in the automated welding process are presented. Both bead width and thermal images from infrared thermography are effected by process parameters. Bead width and isotherm radii can be expressed in terms of process parameters(welding current and welding speed) using mathematical equations obtained by empirical analysis using infrared camera. A linear relationship exists between the isothermal radii producted during the welding process and bead width.

A Study on the Pore Structure of Hardened Alumina Cement Pste by Water Vapor Sorption ($H_2O$ 증착법에 의한 알루미나 시멘트 경화체의 기공구조 연구)

  • 임용무;장복기
    • Journal of the Korean Ceramic Society
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    • v.30 no.4
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    • pp.273-278
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    • 1993
  • Using water vapor (de)sorption isotherm, pore structure analyses were performed for hardened cement pastes by a combination of the "MP-method" for the micropores and the "corrected modelless method" for the wide pores. This work was carried out to investigate the pore structure and to understand the microstructural basis of alumina cement developing much higher strength than Portland cement. Alumina cement shows extremely low microporosity and its wide pores are also composed mainlyof pores with very small radii. And the pore structure analysis results are consistent with the high strength property of alumina cement.y of alumina cement.

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Effect of Curvature Dependency of Surface Tension on the Result of Pore-Volume Distribution Analysis (동공부피 분포의 계산결과에 미치는 표면장력의 곡률 의존도 효과)

  • Cho Chang-Hyun;Ahn Woon-Sun;Chang Seihun
    • Journal of the Korean Chemical Society
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    • v.16 no.6
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    • pp.341-348
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    • 1972
  • The significance of the curvature dependency correction of surface tension is studied in calculating the pore volume distribution of porous adsorbent from nitrogen adsorption isotherm. That is, Kelvin radii are calculated with curvature dependent surface tension values calculated by Chang et al, and then with these Kelvin radii, pore volume distributions of three porous adsorbents, silica alumina (steam deactivated), silica gel (Davidson 59), and silica gel (Mallinc-krodt Standard Luminescent), are calculated. The results are compared with those obtained by the previous method in which surface tension is taken as constant and also with the others. obtained by the modelless method proposed by Brunauer et al. The maximum point of the distribution curve shift to the larger pore radius, when the curvature dependency is considered. Furthermore, the relative pressure at which capillary condensation commences is by far the lower than that accepted previously. This effect becomes significant as the pore radius approaches to the micropore range.

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Adsorption Behavior of Monosubstituted-Halophenols by Amberlite XAD Resins (Amberlite XAD 수지에 대한 일치환 할로 페놀들의 흡착거동에 관한 연구)

  • Lee, Taek Hyeok;Lee, Dae Un
    • Journal of the Korean Chemical Society
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    • v.34 no.3
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    • pp.267-279
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    • 1990
  • The adsorption mechanisms of phenols on XAD-2 and XAD-7 resins were studied by using the distribution coefficient(log Kd) measured in the optimum adsorption conditions. It was observed that the Langmuir adsorption isotherm, indicating a molecular size-dependent adsorption, was appropriate for characterizing the adsorption behaviors of phenols on XAD-2 and XAD-7 resins. The adsorption energies of phenols on XAD resins were calculated by Lennard-Jones potential equation. In the calculation of the adsorption energy, the molecular radii and dipole moments of the resins and phenols were calculated by their van der Waals volumes and Debye equation, respectively. The stacking factor (F) were determined from the radio of the equilibrium distance to the stacking distance of molecules. In order to explain the adsorption energy calculated from the stacking factor it was compared with the adsorption enthalpy for each of phenols which was experimentally determined by batch adsorption shake method. It was observed that the adsorption enthalpy of phenolate ions on the XAD resins was likely to be more seriously affected by dispersion interaction than by a dipole or a charge interaction.

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