Thermal expansion requirements

Hence the polymer is likely to satisfy the thermal expansivity requirement. 

Studying thermal expansion requires the analysis of several phenomena (Incropera and DeWitt 2008 Incropera et al. 2012) ... 

Source fixturing involves making good electrical contact with the resistively heated vaporization source (wire, sheet, etc.). Thermal expansion requires that the fixture be somewhat flexible. If the fixture is rigid, the vaporization source can be stressed and break. If the source is flexible, as with a wire or coil, the source can distort, producing changes in the... 

C. For high temperature application, Cr content varies between 7 and 28%. However, formation of a protective, single-phase chromia layer and matching thermal expansion requires a Cr-content approximately within 17-20% depending upon the temperature, surface treatment, minor alloying additions, and impurities (e.g. C, S, P). With respect to oxidation resistance, the most important minor alloying additions (in ppm level) are Mn, Ti, Si and Al. 

With disk diameters above 5.25 in., all parameters, eg, water absorption and thermal expansion, become more critical which aggravates the expansion or warp of disks. If in the future disk rotation speeds have to be increased significantly to boost data transfer rates, higher demands will be placed on warp (tilt angle) and modulus to avoid creeping (ie, irreversible elongation in radial direction). A survey of the requirement profile for the substrate material of optical disks is given in Table 5 (182,186,187,189). 

Heat Recovery and Seed Recovery System. Although much technology developed for conventional steam plants is appHcable to heat recovery and seed recovery (HRSR) design, the HRSRhas several differences arising from MHD-specific requirements (135,136). First, the MHD diffuser, which has no counterpart ia a conventional steam plant, is iacluded as part of the steam generation system. The diffuser experiences high 30 50 W/cm heat transfer rates. Thus, it is necessary to allow for thermal expansion of the order of 10 cm (137) ia both the horizontal and vertical directions at the connection between the diffuser and the radiant furnace section of the HRSR. 

Electronic-Grade MMCs. Metal-matrix composites can be tailored to have optimal thermal and physical properties to meet requirements of electronic packaging systems, eg, cotes, substrates, carriers, and housings. A controUed thermal expansion space tmss, ie, one having a high precision dimensional tolerance in space environment, was developed from a carbon fiber (pitch-based)/Al composite. Continuous boron fiber-reinforced aluminum composites made by diffusion bonding have been used as heat sinks in chip carrier multilayer boards. 

Because of the high functional values that polyimides can provide, a small-scale custom synthesis by users or toU producers is often economically viable despite high cost, especially for aerospace and microelectronic appHcations. For the majority of iudustrial appHcations, the yellow color generally associated with polyimides is quite acceptable. However, transparency or low absorbance is an essential requirement iu some appHcations such as multilayer thermal iusulation blankets for satellites and protective coatings for solar cells and other space components (93). For iutedayer dielectric appHcations iu semiconductor devices, polyimides having low and controlled thermal expansion coefficients are required to match those of substrate materials such as metals, ceramics, and semiconductors usediu those devices (94). 

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