Metal/stainless steel devices

The interdigital feed can be fed in a counter-flow or co-flow orientation the first principle is realized in metal/stainless-steel devices [23, 25] and the latter in glass devices [24]. Glass mixers allow observation of hydrodynamics, e.g. for process control during reaction. To prolong residence time and/or to increase temperature, tubes are usually attached to interdigital micro mixers. These comprise millimeter dimensions or below, if necessary. 

D microfabricated reactor devices are typically made by fabrication techniques other than stemming from microelectronics, e.g. by modern precision engineering techniques, laser ablation, wet-chemical steel etching or pEDM techniques. Besides having this origin only, these devices may also be of hybrid nature, containing parts made by the above-mentioned techniques and by microelectronic methods. Typical materials are metals, stainless steel, ceramics and polymers or, in the hybrid case, combinations of these materials. 

Chromium makes up just 0.012% of the Earth s crust, yet it is an important industrial metal. The main use of chromium is in metal alloys. Stainless steel, for example, contains as much as 20% chromium. Nichrome, a 60 40 alloy of nickel and chromium, is used to make heat-radiating wires in electrical devices such as toasters and hair dryers. Another important application of chromium metal is as a protective and decorative coating for the surface of metal objects, as described in Chapter 19. 

Wet air pollution control (WAPC) devices are used to treat exhaust gases from stainless steel pickling operations, thereby generating wastewater, which are treated using the selective catalytic reduction (SCR) technology in which anhydrous ammonia is injected into the gas stream prior to a catalyst to reduce NO, to nitrogen and water. The most common types of catalysts are a metal oxide, a noble metal, or zeolite. 

Tellurium s major use is as an alloy with copper and stainless steel. It makes these metals easier to machine and mill (cut on a lathe). It is also used as a vulcanizing agent in the production of rubber, as a coloring agent for glass and ceramics, and for thetffloelectrical devices. 

One of the most commonly used medical devices is the stent, (Fig. 21.1), small metallic structures that are expanded in blood vessels, functioning to maintain the patency (freedom from obstruction) of the vessel in which it is placed. Although the first use of stents was in vasculature (blood vessel systems), more recent applications include, for example, implantation between two vertebrae to increase the rigidity of the spine. A typical vascular stent is placed in its anatomical location and then either plastically deformed/expanded (stainless steel) or allowed to expand to a predetermined size, as a consequence of shape memory (nitinol). 

The metal sampling/sprayer tube that extends the length of the device is a 10 cm long, 31 gauge stainless steel tube. 

The writers are providing what they consider to be additional, but not obligatory, information about the tube. That the tube extends the length of the device is not considered essential in the eyes of the authors. If the which clause (and commas) were deleted, readers would still have access to the information that matters to the authors the metal sampling/sprayer tube is a 10 cm long, 31 gauge stainless steel tube. 

The metal has very little commercial use. In elemental form it is a laser source, a portable x-ray source, and as a dopant in garnets. When added to stainless steel, it improves grain refinement, strength, and other properties. Some other applications, particularly in oxides mixed with other rare earths, are as carbon rods for industrial hghting, in titanate insulated capacitors, and as additives to glass. The radioactive isotope ytterbium-169 is used in portable devices to examine defects in thin steel and aluminum. The metal and its compounds are used in fundamental research. 

Soil samples for VOC analysis are collected into airtight coring devices or into preserved VOA vials. Soil samples for SVOC, metal, and inorganic parameter analyses are collected into brass or stainless steel core barrel liners, acrylic liners, or into glass jars with PTFE-lined lids. The liners are capped with PTFE sheets and plastic caps. 

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