Adhesion rosette

If on each direction of the detaching force, as an axis, we plot the adhesion number yp we obtain a pattern that is termed an adhesion rosette (Fig. 1.6). 

Fig. 1.6. Adhesion rosette (a) and its development (b) as obtained for adhesion of spherical glass particles with 20-30 ptm diameter to a steel surface with a Class 13 finish, for a detaching force of 4.1 10 dyn.

If we set out the adhesion number (y ) along each direction of the detaching forces as axis, we obtain a figure (Fig. 1.5) called the adhesion rosette. The angle ce varies from 0 to 360°. 

The popular adhesively bonded resistance strain gauges provide an accurate, sensitive means of measuring strain at a point. They can be as small as 0.2 by 0. 1 7 cm with a gauge length of 0.02 cm, and in rosette configuration can measure strain in two perpendicular directions. With proper attention to technique, one can obtain resolutions of 1 or 2 cm/cm, and record strain from static to 20 kHz transient conditions. Accuracy is typically 4% of the measured strain but can be better than 1% with special procedures. Standard gauges may be used at temperatures... 

Sialidase-treated erythrocytes from rats, unlike the normal erythrocytes, preferentially adhered to mononuclear spleen cells and Kupffer cells of the liver. This recognition manifests itself, both in autologous and homologous systems, by the adhesion of complementary cells in the form of rosettes. This process may be the normal physiological mechanism for removing circulating erythrocytes that have a decreasing proportion of sialic acid residues. 

Filtration. Except for the in situ pumps, large-volume filtration has to be performed on board, for which a variety of pressure or suction techniques is available (compare with Chapter 2 and Chapter 12, Section 12.6). In order to prevent the loss of any particulate or dissolved activity, the risk of settling of particles and adsorption/adhesion to walls of the sampling bottles has to be considered. If a water pump is used before the filter, it should be carefully checked, e.g., by microscopy, whether the pump leaves the particles intact. Centrifugal pumps are notoriously harmful to plankton. An elegant filtration method has been described by Dehairs et al. (1997). A 30L calibrated Perspex cylinder with a conical bottom is filled with the sample obtained from a Rosette cast. The outlet is connected to a 142 mm Teflon filtration unit. Controlled (50-100 kPa) air pressure is applied to a series of these units from a simple small compressor. 

Zhang, L., Hemraz, U.D., Fenniri, H., Webster, T.J., 2010. Tuning cell adhesion on titanium with osteogenic rosette nanotubes. Journal of Biomedical Materials Research, Part A 95, 550-563. 

The mechanical properties of adhesive and substrate were determined by applying strain gauge rosettes to flat plates of both adhesive and substrate and determining the strain response to small applied stresses In the elastic range. Poisson s ratios for the materials were calculated from the slopes of the graphs of axial to lateral strain. The results of the determination of the mechanical constants are shown In Table 111. 

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