• Title, Summary, Keyword: Adhesion

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Adhesion of clay to metal surface; Normal and tangential measurement

  • Basmenj, Amir Khabbazi;Ghafoori, Mohammad;Cheshomi, Akbar;Azandariani, Younes Karami
    • Geomechanics and Engineering
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    • v.10 no.2
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    • pp.125-135
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    • 2016
  • Adhesion in geotechnical engineering is the interaction between cohesive soil and a solid surface which can cause clogging in mechanized tunnelling through clayey formations. Normal piston pull out and modified direct shear tests were performed on clayey soil samples to determine which type of adhesion stress, normal or tangential, could be most effectively measured. Measured values for normal adhesion ranged from 0.9 to 18 kPa. The range of tangential adhesion was 2.4 to 10 kPa. The results indicate normal adhesion results were more accurate than those for the modified direct shear test that measure tangential adhesion. Direct shear test on identical samples did not show any correlation between measured cohesion and normal adhesion values. Normal adhesion values have shown significantly meaningful variation with consistency index and so are compatible with the base of field clogging assessment criteria. But tangential adhesion and cohesion were not compatible with these assessment criteria.

Characterization of Adhesion of Bifidobacterium sp. BGN4 to Human Enterocyte-Like Caco-2 Cells

  • Kim, In-Hee;Park, Myung-Soo;Ji, Geun-Eog
    • Journal of Microbiology and Biotechnology
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    • v.13 no.2
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    • pp.276-281
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    • 2003
  • The adhesion of probiotic bacteria to the intestinal mucosa is one of the desirable properties for their colonization in the intestinal tract, where these bacteria constantly compete with other bacteria. The adhesion of different strains of bifidobacteria to Caco-2 cells was compared. Among the strains examined, BGN-4 showed the highest adhesion level and the greatest cell surface hydrophobicity (CSH). No close relationship was found between the adhesion and CSH of the strains. Upon protease and heat treatment, the adhesion of the BGN-4 to the Caco-2 cells decreased significantly. The cells grown at $42^{\circ}C$ showed a lower CSH and self-aggregation levels than cells grown at $37^{\circ}C$. The treatment of EGTA did not have any effect on the adhesion. The degree of adhesion did not differ among the experimental groups in which galactose, mannose, or fucose were added in the adhesion assay mixture. The results suggest that the adhesion of the Bifidobacterium to the epithelial cells may be affected by the composition and structure of the cell membrane and interacting surfaces.

A Study on the Adhesion Control using the Estimated Adhesion for Improving Traction Performance (견인능력 향상을 위한 추정점착력을 이용한 점착제어기법에 관한 연구)

  • Seo, Gwang-Deok
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.48 no.12
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    • pp.709-714
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    • 1999
  • This paper is focused on the adhesion control method to improve traction efficiency using the estimated adhesion for railway propulsion system. Recently, the wheel slippery is frequently occurred due to light weight of train and power increasement of traction parts. This phenomenon occurs a traction loss and a poor ride comport. Therefore, the adhesion control which is able to prevent the slippery and to control the traction on a maximum adhesion is absolutely needed. This paper introduces typical methods for adhesion control and proposes two novel adhesion methods using the estimated adhesion.

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Mechanical/Biochemical Analysis of Cell Adhesion Strengthening (세포흡착 거동의 기계적/생화학적 분석)

  • Shin, Heung-Soo
    • Proceedings of the KSME Conference
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    • pp.1455-1457
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    • 2008
  • Cell adhesion is a coordinated process involving initial binding of integrin receptors to extracellular matrix (ECM), recruitment of adhesion proteins, and focal adhesion assembly. The formation of mechanically stable focal adhesion assembly of cells within surrounding ECM is a key parameter to direct numerous cellular functions including cell migration, differentiation, and apotosis. With current cell adhesion assays, it is difficult to understand contributions of each coordinated event on evolution of cell adhesion strengthening since cells spontaneously spread upon their adhesion to the substrate, thus remodeling their cytoskeletal structure. In this presentation, novel approaches for analysis of cell adhesion strengthening process based on the combination of mechanical device, micro-patterned substrates, and molecular biological techniques will be discussed.

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A Study on Adhesion Friction Characteristics of Rubber for Tire Tread

  • Oh, Yumrak;Jeon, Seong-hee;Lee, Dong Youm;Kim, Hak-Joo;Kim, Jeong-Heon
    • Elastomers and Composites
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    • v.54 no.4
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    • pp.299-307
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    • 2019
  • Rubber friction properties include adhesion friction characteristics of the interface, hysteresis friction characteristics originating from repeated rubber deformations, and cohesion friction characteristics due to wear and tear. Cohesion friction is generally sufficiently small (< 3%) that it can be ignored, whereas adhesion friction has a relatively large contribution of 15%, but has not been investigated thoroughly. Therefore, through an adhesion friction study, the adhesion mechanism was examined and the relationship between friction characteristics and adhesion friction on dry surfaces was derived. The wet grip characteristics of tread rubber are fully described by the hysteresis characteristics of tires, but friction characteristics on dry roads are difficult to determine without adhesion factors. The results presented herein demonstrate that the combination of hysteresis and adhesion properties in the tread rubber sufficiently explained the characteristics of the dry grip. Based on the results of this study, technologies will be developed to determine the key factors governing adhesion friction characteristics and improve dry tire braking performance.

Characteristics of adhesion areas between the tissue expander and capsule in implant-based breast reconstruction

  • Lim, Yoon Min;Park, Kwang Hyun;Lee, Dong Won;Lew, Dae Hyun;Roh, Tai Suk;Song, Seung Yong
    • Archives of Plastic Surgery
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    • v.46 no.4
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    • pp.330-335
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    • 2019
  • Background The use of anatomic implants has improved the aesthetic results of breast surgery; however, implant malrotation is an uncommon, but serious complication of these procedures. Nevertheless, little research has explored implant adhesion. In this study, we investigated adhesion between the expander and the capsule. Methods Seventy-nine cases of immediate breast reconstruction via two-stage implant-based reconstruction performed between September 2016 and November 2017 were evaluated. Mentor CPX4 expanders were used in 14 breasts, and Natrelle expanders in 65. We analyzed areas of adhesion on the surfaces of the tissue expanders when they were exchanged with permanent implants. We investigated whether adhesions occurred on the cephalic, caudal, anterior, and/or posterior surfaces of the expanders. Results Total adhesion occurred in 18 cases, non-adhesion in 15 cases, and partial adhesion in 46 cases. Of the non-adhesion cases, 80% (n=12) were with Mentor CPX4 expanders, while 94.4% (n=17) of the total adhesion cases were with Natrelle expanders. Of the partial adhesion cases, 90.7% involved the anterior-cephalic surface. The type of tissue expander showed a statistically significant relationship with the number of attachments in both univariate and multivariate logistic regression analyses (P<0.001) and with total drainage only in the univariate analysis (P=0.015). Conclusions We sought to identify the location(s) of adhesion after tissue expander insertion. The texture of the implant was a significant predictor of the success of adhesion, and partial adhesion was common. The anterior-cephalic surface showed the highest adhesion rate. Nevertheless, partial adhesion suffices to prevent unwanted rotation of the expander.

Modulatory Effect of BAY11-7082 on CD29-mediated Cell-cell Adhesion in Monocytic U937 Cells (BAY11-7082에 의한 U937 세포의 CD29-매개성 세포간 유착과정 조절 효과)

  • Kim, Byung-Hun;Cho, Jae-Youl
    • YAKHAK HOEJI
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    • v.52 no.5
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    • pp.412-417
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    • 2008
  • BAY11-7082 was initially found to be an anti-inflammatory drug with NF-${\kappa}B$ inhibitory property. In this study, we evaluated modulatory function of BAY11-7082 on U937 cell-cell adhesion induced by CD29 (${\beta}1$-integrins). BAY11-7082 strongly blocked functional activation of CD29 (${\beta}1$-integrins), as assessed by cell-cell adhesion assay. However, this compound did not block a simple activation of CD29, as assessed by cell-fibronectin adhesion assay. In particular, to understand molecular mechanism of BAY11-7082-mediated inhibition, the regulatory roles of CD29-induced actin cytoskeleton rearrangement under cell-cell adhesion and surface level of CD29 were examined using confocal and flow cytometic analysis. Interestingly, this compound strongly suppressed the molecular association of actin cytoskeleton with CD29 at cell-cell adhesion site. Moreover, BAY11-7082 also diminished surface levels of CD29 as well as its-associated adhesion molecule CD147, but not other adhesion molecules such as CD18 and CD43. Therefore, our data suggest that BAY11-7082 may be involved in regulating immune responses managed by CD29-mediated cell-cell adhesion.

A Study on the adhesion characteristic technique for improvement performance of urban rolling stock (도시철도차량의 성능 향상을 위한 점착특성 기법에 관한 연구)

  • Kim, Young-Choon;Chun, Ji-Yong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.7 no.2
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    • pp.150-156
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    • 2006
  • It is one of the most effective methods for improving the performance of electric railway vehicles to make better the wheel-rail adhesion characteristics. To study adhesion characteristic is to develop the equivalent reduction machine to experiment on the adhesion system. The experiment system makes it possible to change the wheel-rail adhesion force with various adhesion parameters, and therewith to test the adhesion control system with the reduction machine in a laboratory. In this paper, for improving adhesion performance shows actually control methods.

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A Study on the Unfairness of Adhesion Contracts for Internet Contents Service (인터넷 콘텐츠서비스 이용약관의 불공정성 검토에 관한 연구)

  • Park Mi Hye;Kang Lee Ju
    • Journal of the Korean Home Economics Association
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    • v.42 no.12
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    • pp.123-140
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    • 2004
  • The purpose of this study was to explore the unfairness of adhesion contracts for internet contents service. The internet contents were classified into six types of avatar, learning, download, e-book and movie internet sites. The adhesion contracts of internet contents service were collected in 60 internet sites. The unfairness of the adhesion contract was reviewed under the adhesion contract regulation act. The major results were as follows. First, the obligation of clear statement, explanation, and delivery was not observed completely. Second, many articles of adhesion contract were unfair and they especially violated articles 7 and 9. Therefore, the standard adhesion contract system for internet content service should be enforced and self-regulation of information service providers is needed.

An Experimental Study on the Effect of Surface Roughness on Nanoscale Adhesion (표면 거칠기가 나노 응착력에 미치는 영향에 관한 실험적 연구)

  • Yang Seung Ho
    • Tribology and Lubricants
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    • v.21 no.1
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    • pp.1-7
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    • 2005
  • Effect of Surface roughness on nanoscale adhesion was studied experimentally by using colloidal probe technique. Glass micro balls having the radius of $3.3\~17.4{\mu}m$ were glued at the end of AFM cantilevers to prepare colloidal probes. Adhesion force between the colloidal probe and Si-wafer was measured using pull-off force measuring method. Results showed that the measured adhesion forces are not the function of the radius of the glued balls because the ball surfaces are rough. It is also found that roughness parameters such as $R_a,\;R_q\;and\;R_{max}$ do not have important role on nanoscale adhesion. In order to find the effect of surface roughness on nanoscale adhesion, the bearing areas were extracted from the measured topography of glued balls. After normalizing the measured adhesion force with the bearing area, it was found that the normalized adhesion force kept constant as function of the radius of glued ball.