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Contact measurements

Fig. 22. Nomialized pull-off energy measured for polyethylene-polyethylene contact measured using the SFA. (a) P versus rate of crack propagation for PE-PE contact. Change in the rate of separation does not seem to affect the measured pull-off force, (b) Normalized pull-off energy, Pn as a function of contact time for PE-PE contact. At shorter contact times, P does not significantly depend on contact time. However, as the surfaces remain in contact for long times, the pull-off energy increases with time. In seinicrystalline PE, the crystalline domains act as physical crosslinks for the relatively mobile amorphous domains. These amorphous domains can interdiffuse across the interface and thereby increase the adhesion of the interface. This time dependence of the adhesion strength is different from viscoelastic behavior in the sense that it is independent of rate of crack propagation. Fig. 22. Nomialized pull-off energy measured for polyethylene-polyethylene contact measured using the SFA. (a) P versus rate of crack propagation for PE-PE contact. Change in the rate of separation does not seem to affect the measured pull-off force, (b) Normalized pull-off energy, Pn as a function of contact time for PE-PE contact. At shorter contact times, P does not significantly depend on contact time. However, as the surfaces remain in contact for long times, the pull-off energy increases with time. In seinicrystalline PE, the crystalline domains act as physical crosslinks for the relatively mobile amorphous domains. These amorphous domains can interdiffuse across the interface and thereby increase the adhesion of the interface. This time dependence of the adhesion strength is different from viscoelastic behavior in the sense that it is independent of rate of crack propagation.
Contact temperature measurement is based on a sensor or a probe, which is in direct contact with the fluid or material. A basic factor to understand is that in using the contact measurement principle, the result of measurement is the temperature of the measurement sensor itself. In unfavorable situations, the sensor temperature is not necessarily close to the fluid or material temperature, which is the point of interest. The reason for this is that the sensor usually has a heat transfer connection with other surrounding temperatures by radiation, conduction, or convection, or a combination of these. As a consequence, heat flow to or from the sensor will influence the sensor temperature. The sensor temperature will stabilize to a level different from the measured medium temperature. The expressions radiation error and conduction error relate to the mode of heat transfer involved. Careful planning of the measurements will assist in avoiding these errors. [Pg.1136]

In Fig. 6.1, an attempt is made to show to what extent sensors have been penetrating the appliance market over the past years, a trend which is set to continue in the next decade. In the beginning, there were relatively simple sensors for temperature, pressure, flow, etc. Over the last years, non-contact measuring devices have attracted much attention, such as non-contact temperature monitoring for toasters or for hair blowers. The introduction of more complex sensor systems, such as water quality sensors or multi gas sensing artificial noses is imminent. [Pg.211]

Alternatively non-contacting measurement systems may be considered for distinguishing between the different textile families, e.g. based on analyses of the optical or infrared optical spectra of the textiles. However, difficulties will arise, considering the variety of textiles in use. [Pg.226]

Figure 11.17 Temperature probes for contact measurement, (a) The reflection-type probe, (b) the transmission-type probe. Figure 11.17 Temperature probes for contact measurement, (a) The reflection-type probe, (b) the transmission-type probe.
Figure 27. Schematic for solid-state electrical measurements with ultrathin polymer separators electrodeposited onto planar indium—tin oxide (ITO) or Au substrates. The top electrode makes a soft contact with the polymer by slow evaporation of Au or direct contact with a liquid metal (either Hg or Gain eutectic) using a micrometer-controlled syringe to control the approach to contact. Measurements are made in an argon-filled glovebox to minimize effects of O2 and H2O. Figure 27. Schematic for solid-state electrical measurements with ultrathin polymer separators electrodeposited onto planar indium—tin oxide (ITO) or Au substrates. The top electrode makes a soft contact with the polymer by slow evaporation of Au or direct contact with a liquid metal (either Hg or Gain eutectic) using a micrometer-controlled syringe to control the approach to contact. Measurements are made in an argon-filled glovebox to minimize effects of O2 and H2O.
No attempt will be made in this section to consider all the separate measurement clauses to be found in current test method standards. Until the ISO standard for the measurement of dimensions has become established long enough for all test methods to have been revised and reference it (if that happens), each test method will have its own procedure and there will not be universal agreement on detail. The essentials are to distinguish between a non-contact measurement and one applying a specified pressure, in the latter case to use the correct standard pressure, and to measure within the accuracy limits specified. [Pg.101]

Figure 8.7 Four-contact measurement of electrolytic conductance. Figure 8.7 Four-contact measurement of electrolytic conductance.
Non-contact measurements with the probe head sited remotely from the process are well established. Tumuluri et al. [10] have described a probe-based process measurement for monitoring the drug content in an extruded film. A commercially available probe head with a working distance of around 5 cm gave excellent results for quantitative monitoring of the process in real time. Appropriate working distance can be up to tens of centimetres depending on the application. However, for many pharmaceutical processes that involve... [Pg.247]

Complementary to the SFA experiments, SFM techniques enabled direct, non-destructive and non-contact measurement of forces which can be as small as 1 pN. Compared to other probes such as optical tweezers, surface force balance and osmotic stress [378-380], the scanning force microscope has an advantage due to its ability in local force measurements on heterogeneous and rough surfaces with excellent spatial resolution [381]. Thus, a force-distance dependence measured from a small surface area provides a microscopic basis for understanding the macroscopic interfacial properties. Furthermore, lateral mapping... [Pg.124]

Marmur A. (2006) Soft contact measurement and interpretation of contact angles. Soft Matter 2 12-17. [Pg.53]

Fig. 9.5. The depletion potential profile of a-Si H with platinum and chromium contacts measured by transient photoconductivity. The inset plots the dependence of the charge collection, Q., on applied bias which shows the shrinking of the depletion width in forward bias (Street 1983). Fig. 9.5. The depletion potential profile of a-Si H with platinum and chromium contacts measured by transient photoconductivity. The inset plots the dependence of the charge collection, Q., on applied bias which shows the shrinking of the depletion width in forward bias (Street 1983).
As a result of re-orientation, the film becomes less abrasive, and the coefficient of friction decreases. Because re-orientation begins rapidly with sliding contact, measurements of kinetic friction will often not show the decrease in friction unless friction monitoring is continuous from the commencement of sliding, when a trace such as that shown in Figure 11.2 may be obtained . This is very similar to the trace shown in Figure 6.3 for a rubbed film of molybdenum disulphide powder. [Pg.197]

In some situations, the stressor can he measured at the actual point of contact while exposure occurs. An example is the use of food collected from the mouths of nestling birds to evaluate exposure to pesticides through contaminated food (Kendall, 1991). Although such point-of-contact measurements can be difficult to obtain, they reduce the need for assumptions about the frequency and magnitude of contact. [Pg.449]

A non-contact measuring system to provide a three-dimensional image of the log. [Pg.243]

A Volta potential difference usually arises between two condensed phases when they come into contact. Because these phases have different chemical properties, charge may be redistributed at their interface with air, even though this interface carried no net charge before contact. Measurement of the Volta potential difference is possible in a high-impedance electrochemical cell which contains an air gap. The potential drop across this cell is determined under conditions for which the potential drop across the air gap is zero, and is known as the compensation potential difference. [Pg.408]

Lenhof, H. P. (1997). New contact measures for the protein docking problem. In RECOMB97 - Proceedings of the first annual international conference on computational molecular biology. ACM. [Pg.416]

Thomson, R.E. and Moreland, J., Development of highly conductive cantilevers for atomic-force microscopy point-contact measurements,/. Vac. Sci. TechnoL, B 13 (3), 1123-1125, 1995. [Pg.337]

Gajewski, J. B., Mathematical Model of Non-Contact Measurements of Charges While Moving, J. Electrostatics, 15, 1984, p. 81. [Pg.104]

The contact measurements can be carried out using both in situ and on line methods. The difference is that whereas in the case of the in situ measurement the sensors are immersed directly in the investigated water, in the case of the on line measurement the sample of water is transported by a pump into a building sited on the bank or to a sensor situated in another place. [Pg.322]

It was observed that the crystallization rate during the first hour of contact, measured by... [Pg.35]


See other pages where Contact measurements is mentioned: [Pg.1067]    [Pg.1135]    [Pg.131]    [Pg.419]    [Pg.357]    [Pg.68]    [Pg.208]    [Pg.222]    [Pg.102]    [Pg.244]    [Pg.251]    [Pg.41]    [Pg.279]    [Pg.211]    [Pg.1837]    [Pg.21]    [Pg.21]    [Pg.398]    [Pg.131]    [Pg.254]    [Pg.93]    [Pg.319]    [Pg.127]    [Pg.612]    [Pg.171]    [Pg.234]   
See also in sourсe #XX -- [ Pg.32 ]

See also in sourсe #XX -- [ Pg.378 , Pg.379 ]




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