Clamping devices

Anode-cathode / Voltage clamping device / monitoring Cathode shell... 

There are also strap-on type Brinell testers in which the anvil is supplanted by a chain or other clamping device and the indenter is spring-loaded. These have the advantage of being able to test direcdy very large objects without the need for cutting samples. 

Since the ends of compression specimens usually tend to flower and not remain rigid, test results are usually very scattered requiring close examination as to what the results mean in reference to the behavior of the test specimens. Different clamping devices are used to eliminate the flowering action that could provide inaccurate readings that in turn influence results by usually making them stronger. 

The clamping devices can be made from a 1/8-in. metal strip, chair gliders, and wing nuts. 

A variety of automatic voltage clamp devices with special modifications have been extensively utilized in electrophysiological studies of /sc in several ocular tissues including the amphibian corneal epithelium [42] and human fetal retinal pigment epithelium [43, 44], as well as non-ocular tissues like the rat tracheal epithelium [45], A strong temperature dependency and inhibitory effect of serosally instilled ouabain on the rabbit conjunctival /sc are characteristic of active ion transport driven by Na+/K+-ATPases in the conjunctiva [6, 7],... 

Unless a proprietary clamping device is specified (see 6.2.11), flexible couplings shall be keyed to the shaft. Keys, keyways, and fits shall conform to AGMA 9002, Commercial Class. 

If specified, couplings shall be fitted with a proprietary clamping device. Acceptable clamping devices may... 

In practice, most molds are flexible and will deform when the fiber volume fraction becomes too high (which corresponds to a high compaction pressure). The forces associated with the compaction can be so high that the mold surface becomes dented or even that the entire mold breaks (if the clamping device is powerful enough). 

The tolerances of the molded part are to a large extent determined by the properties of the mold. The most fundamental property for the tolerances is probably the stiffness of the mold. This is particularly important in LCM due to the large forces that can be generated by the injection pressure. As an example, an injection pressure of 4 bar will exert a force of 800 kN or 80 tons on a mold with a surface area of 2 m2. This force has to be reacted by the clamping device and the mold. 

The low stiffness necessitates rigid supporting and clamping devices moreover the forces exerted should not be too high. 

Film welding requires special precautions in view of the small thickness. When the two overlapping ends are heated by an external heat source, the heat is supplied at the wrong side of the film so that the films are heavily distorted. With very short electric pulses good welds can be made, though only with thin films (up to 0.2 mm), and with special precautions to avoid sticking of the film to the clamping device. 

It is much more attractive to heat the films from the inside, namely by the application of a high-frequency electric field. In this case the clamping device remains cold, and the highest temperature is generated at the surfaces to be welded together. Only polymers with a not too low dielectric loss factor (see 8.2.2) are suitable for this process, such as PVC and PMMA. PE, PP and PS, on the contrary, cannot be welded in this way. 

Zahoransky et al. described an improved Fl-FFF channel which assures a uniform cross-flow in the whole channel [476]. This is achieved by a division of the hollow compartment under the membrane supporting frit into three separate chambers with an independent pressure control. By means of special spring-loaded clamping devices, the spacer and membrane change is reported to be simple, thus making the whole experimental handling with this new channel convenient. 

Figure 1.12 Rotating clamp device used by Meissner to impose a uniaxial extensional strain on a cylindrical filament of polymer of length Lq. Leaf springs in one of the sets of rotating clamps allow the extensional stress to be measured. (From Meissner 1971, reprinted with permission from Steinkopff Publishers.)...

Electric resistivity. The electric resistance measurement is the same as discussed below under volume resistivity, to which this measurement is temporary adapted. For flexible materials, special electrode systems are developed to clamp sample and electric wires. The measuring equipment is based on a Wheatstone bridge circuit. The conductivity of metal powder-containing epoxy was measured in special dies equipped with built-in brass electrodes inserted to the die. The material was cured in the die to assure good contact with electrodes. Special sample holders and clamping devices are used for precise determination of rubber compounds containing carbon black. ... 

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