Backing materials

Backer laminates Backing materials Backmixing Backset... 

Figure 5 shows a typical metallic foil strain gauge. It consists of an etched grid of very thin foil attached to a thin insulating backing material. The... 

The resins should dry quickly and cure weU at low temperatures. They usually are made at a high pH with high ratios of formaldehyde to phenol and held to fairly low molecular weight. Typical viscosities are 15, 000 mPa-s(=cP) at 75% soHds content for a first coat and 1000 mPa-s(=cP) at 50% soHds for the top resin. For dense backing materials, such as fiber disks, a typical resin has a viscosity of 50, 000 mPa-s(=cP) at 80% soHds and is cured at 148°C. 

A grass-like recreational surface system includes the top material directly available for use and observation, backing materials that serve to hold together or reinforce the system, fabric-backing finish, a shock-absorbing underpad system if any, and adhesives (qv) or other joining materials. The system is installed... 

The knitted fabric is subjected to a finishing operation in which a suitable backing material is appHed to penetrate the yam contact points and stabilize the stmcture. This process is usually accompanied by a heat treatment which stabilizes the fabric and conditions the pile. 

For high, fatigue strength in automotive bearings, a very thin layer of babbitt is desirable so that much of the load is taken on a stronger backing material. Relative improvement in fatigue resistance was found to be as follows with tin babbitt (14) ... 

Fig. 4. Cross-section of a reservoir type of transdermal dmg deUvery system. The backing material and heat seals at the periphery of the system prevent loss...

Thermal conductive backing material to dissipate heat developed in oil film. 

The thrust-carrying capacity can be greatly improved by maintaining pad flatness and removing heat from the loaded zone. By the use of nigh thermal conductivity backing materials with proper thickness... 

Clad Tube Sheets Usually tube sheets and other exchanger parts are of a solid metal. Clad or bimetallic tube sheets are usecito reduce costs or because no single metal is satisfactory for the corrosive conditions. The alloy material (e.g., stainless steel, Monel) is generally bonded or clad to a carbon steel backing material. In fixed-tube-sheet construction a copper-alloy-clad tube sheet can be welded to a steel shell, while most copper-alloy tube sheets cannot be welded to steel in a manner acceptable to ASME Code authorities. 

Ferrous-aUoy-clad tube sheets are generally prepared by a weld overlay process in which the alloy material is deposited by welding upon the face of the tube sheet. Precautions are required to produce a weld deposit free of defects, since these may permit the process fluid to attack the base metal below the alloy. Copper-aUoy-clad tube sheets are prepared by brazing the alloy to the carbon steel backing material. 

Silicone rubber as a shaft seal and backing material has a number of special applications. It can be used over a temperature range of —60°C to 260°C (—76°F to 500°F) in air or suitable fluids. Its abrasion resistance is good with hard shafts having a 0.000254 mm RMS surface finish. Commercial grades of silicone rubber are compatible with most industrial chemicals up to 260°C (500°F). In lubricating oils, the limiting temperature is 120°C (250°F), but special types have been developed for use up to 200°C (392°F). 

The Nigorikawa (Mori) geothermal system is located in southwest Hokkaido (Fig. 2.15). The area is composed of basement rocks (sedimentary rocks such as limestone), and Tertiary andesitic rocks (Yoshida, 1991). The area is characterized by a Krakatoan-type caldera which was formed by volcanic activity about 12,000 to 20,000 years ago (Sato, 1988). The caldera is filled with sediments consisting of clays, conglomerate, and fall back materials (tuff and tuff breccia). The rock formations surrounding the caldera consist of pre-Tertiary rock which are unconformably overlain by the Neogene Tertiary formation in thicknesses of 300-700 m. 

A rubber-based adhesive usually applied to a backing material which may therefore be applied to a surface by quite light pressure. 

Polyester cloth-backed flat PP sheets (fleece-backed sheets) are normally used to manufacture large reservoirs for liquid containment purposes. Typically, such reservoirs are reinforced on the outside with fiberglass. The polyester mat backing serves as an adhesion key between the PP and the fiberglass resin. Fluorine surface activation can be used as a substitute for the fleece-backed material at a considerable cost-saving. Table 16.12 shows a comparison between the adhesive performance of the materials with two polyester resins. 

Divisek et al. presented a similar two-phase, two-dimensional model of DMFC. Two-phase flow and capillary effects in backing layers were considered using a quantitatively different but qualitatively similar function of capillary pressure vs liquid saturation. In practice, this capillary pressure function must be experimentally obtained for realistic DMFC backing materials in a methanol solution. Note that methanol in the anode solution significantly alters the interfacial tension characteristics. In addition, Divisek et al. developed detailed, multistep reaction models for both ORR and methanol oxidation as well as used the Stefan—Maxwell formulation for gas diffusion. Murgia et al. described a one-dimensional, two-phase, multicomponent steady-state model based on phenomenological transport equations for the catalyst layer, diffusion layer, and polymer membrane for a liquid-feed DMFC. 

Toray s data are plotted as the reciprocal of membrane constants against time elasped like Fig. U. The first generation of Toray module tested at the laboratory might have some defect In the membrane backing material. After 6000 hours in operation, they exchanged half of the modules for the second generation chlorine resistant. The second had been improved about twice in its resistance against flux decline. 

Styrene-1,3-butadiene copolymers with higher styrene contents (50-70%) are used in latex paints. Styrene and 1,3-butadiene terpolymerized with small amounts of an unsaturated carboxylic acid are used to produce latexes that can be crosslinked through the carboxyl groups. These carboxylated SBR products are used as backing material for carpets. Styrene copolymerized with divinyl benzene yields crosslinked products, which find use in size-exclusion chromatography and as ion-exchange resins (Sec. 9-6). 

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