Resistivity, solution-specific

Udel is a slightly yellow but tianspaient engineering thermoplastic. It has low flammability and smoke emission and good electrical properties. It has excellent resistance to water, steam, and alkaline solutions. Specific uses for Udel iaclude microwave cookware, beverage dispensers, coffee brewers, cookware, hair dryers, com poppers, and steam table trays. Its steam resistance makes it particularly fit for a dishwasher environment. Properties of polysulfone resias ate given ia Table 11. 

Using this local moment model, and using band theory or its variations, a number of workers have been able to formulate expressions which represent the measured magnetic data reasonably well, at least for the case where well-localized moments are developed on the solute atoms (II, 18). However, considerably more data has become available on other properties of dilute alloys, including data on resistivity and specific heat, neutron scattering, various magnetic resonance experiments, Moss-bauer measurements, Kondo effect, and the like. Measurements have been extended also to alloys of many other systems besides those involving the platinum metals. 

The distribution of potential in the solution along the solution/metal interface is shown in Fig. 4.6. If the anode and cathode areas are not connected, they will exhibit their thermodynamic or open circuit potentials, with the potentials in the solution at the anode and cathode being equal to +1000 mV and 0 mV, respectively. When the anode and cathode areas are in contact, current will pass causing polarization of the interface reactions. With a solution-specific resistivity of 1000 ohm-cm, the solution potential at the center of the anode is decreased... 

Dj is proportional to the fixed ion concentration of the membrane and inversely proportional to the specific flow resistance and specific conductivity. Also, Df is independent of membrane thickness. Figure 2.6 shows the change in electro-osmotic water transport with the fixed ion concentration of an anion exchange membrane measured with 0.5 N sodium chloride solution.25 Dj decreases with increasing fixed ion concentration. The specific conductance of the membrane increases and the water content of the membrane decreases (po increases) with increasing fixed ion concentration of the membrane. The electro-osmotic behavior through the membrane is not simply explained from this experimental data. 

Materials of Construction for Pumps. The materials used in pump construction depend upon the service demanded. Although all-purpose, corrosion-resisting materials do not exist, there are materials that have great resistance to specific corrosive reagents, and the knowledge of the chemical reactivity between various chemical solutions and materials of construction is nece.ssary in proper pump selection. 

The use of pure talcs of fine particle and high lamellarity index, in eombination with a new generation bromohalogenated compound, makes it possible to obtain optimum mechanical properties and fire resistance as well as limitation of emissions of eorrosive products, compared to traditional and more costly solutions. Specific talcs in the Luzenac range show high resistanee to flame in polyolefins in synergy with bromine compounds, and are recommended for various applieations, such as cormectors in electrical installations and appliances. 

Photoprint. Photoprint involves a supplier coating a thin, resistive layer on a copper-foil sheet and selling this to either a laminate suppher or directly to the board fabrication shop. The fabricator uses two imaging and etching steps the first to image the copper conductors on the layer, and the second to size individual resistors by using a second, different etchant solution, specifically for the resistor composition. Typically, alkaUne etchants are used in step one, and acidic etchants are used in step two. 

The overall view of chemical attack is impossible to condense because of the wide variety of chanical species and polymeric substrates. Whenever a polymer is suggested as a material of construction in a chemical plant, a thorough consideration of resistance to specific chemicals is desirable. Polymeric pipes and tank liners are used for acids and alkalis, oxidizing and reducing agents, and all kinds of organic reactants. In each case the most economical solution will be specific, because factors of initial cost, versatility, and maintenance may enter in. 

The scale-up of conventional cake filtration uses the basic filtration equation (eq. 4). Solutions of this equation exist for any kind of operation, eg, constant pressure, constant rate, variable pressure—variable rate operations (2). The problems encountered with scale-up in cake filtration are in estabHshing the effective values of the medium resistance and the specific cake resistance. 

---