Poor Contact

These are made by crosslinking unsaturated oils with sulphur (and an amine catalyst, usually triethanolamine) at 140-160 °C. These products will give dark coloured vulcanisates which have poor contact stain properties when in contact with painted surfaces. 

Whole body Variety and number of animals Chronic studies possible Minimum restraint Large historical database Controllable environment Minimum stress Minimum labor Messy Multiple routes of exposure skin, eyes, oral Variability of dose Cannot pulse exposure easily Poor contact between animals and investigators Capital intensive Inefficient compound usage Difficult to monitor animals during exposure Cleaning effluent air Inert materials Losses of test material Even distribution in space Sampling Animal care Observation Noise, vibration, humidity Air temperature Safe exhaust Loading Reliability... 

However, high electrolyte conductivity on its own does not necessarily guarantee low polarization in a solid state cell. Electrode/electrolyte inter-facial resistance must also be taken into account, and in contrast to the more familiar situation with conventional aqueous systems where the solid electrodes are uniformly wetted by the liquid electrolyte, the all-solid configuration of the cell may create non-uniform contact at the interfaces. Differential expansion and contraction of electrodes and electrolyte may lead to poor contact (and consequent high internal resistance due to low effective electrode/electrolyte interfacial area) or even to a complete open circuit during cell operation. The situation is even more serious with secondary cells, as illustrated schematically in Fig. 9.4, where the effects... 

Do this quickly and do not reposition a double image will be formed if the membrane is moved while in contact with the film. A blurred image is usually caused by poor contact between membrane and film use a film cassette that ensures a tight fit. 

Electrical intermittents caused by poor contacts of printed circuit boards (PCBs) is a major source of problems for navigational computers used on nuclear submarines. The cause of the intermittencies has been traced to the presence of dirt, tarnish, corrosion products and organic contaminants accumulating at the pin connector junctions (50). 

But the film thickness doesn t change, so how can the coercive voltage increase And the same capacitor can show its true coercive voltage of e.g. 2 Volts after a few measurements. So it appears to be a contact problem, though a pure platinum electrode is contacted to a pure Ptlr alloy coated cantilever, so an excellent contact should be expected. To investigate the reason of this poor contact behavior, afm conductivity scans were performed on a pure Pt coated... 

Figure 17.7 Artificially increased coercive voltage created by poor contact quality...

The initial scan shows indeed a very poor contact (Figure 17.8). At a voltage of 1V the current is below 1 nA and the conductivity is dependent on voltage and also on the location of the contact within the scanned area. After a thermal treatment of 5 min at 200°C the conductivity scan showed excellent conductivity on the whole scan area and at 0.01 V the current amplitude rises to more than 300 nA, so the conductivity increases by more than five orders of magnitude, see Figure 17.9. The reason for this behavior can be described by surface contamination. But the analytical description of the electrical behavior of this surface layer, which is mostly related to water and carbon, is hardly possible. An analytical description of the electri-... 

For currents exceeding approx. 500 mA it shall be taken into account that inadmissible high temperatures may occur for inadequate small conductor cross-sections (cable near to breakoff ) or for poor contact making (terminal tightened insufficiently). This effect is well known as ignition by incandescence. 

When a graphite tube is used, different interference effects appear. These can be caused by the sample as well as by the specific instrument [24], Interferences caused by the sample occur when the element is vaporised as a molecule, the chemical compound hinders atomisation, or when after vaporisation of the matrix the sample has poor contact with the graphite tube. Also, unspecific absorption can occur by simultaneous vaporisation of the matrix. Here, molecular absorption or light loss by scattering from solid particles are the most common effect. 

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