Warping water

Fill Warping, water channeling Replace as needed. 

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). 

Poly(methyl methacrylate). PMMA offers distinct advantages over BPA-PC with respect to significandy lower birefringence, higher modulus, and lower costs, but has not been successhil as a material for audio CDs and CD-ROM as well as a substrate material for WORM and EOD disks because of its high water absorption (which makes it prone to warp) and its unsuitabiUty for metallising, and less so because of its low resistance to... 

When selecting a particular paster adhesive, coating material, and coating process for sohd fiber packaging, the fact that sohd fiberboard lacks the open-flute stmcture (to facihtate exit of moisture from internal phes of paperboard) should be considered. It is generally desirable to minimize the amount of process water added with the adhesive or coating with sohd fiber products. Moisture trapped in the filler phes can result in pin holes or bhsters in the coating and/or warp of the sheet (15). 

Wood chipboard is free from grain and is thus essentially isotropic in its behaviour. The mechanical properties are approximately the same as the average of the properties of the original wood measured along and across the grain. The water resistance of chipboard is poor but, being isotropic, it does not warp as long as it is able to swell freely in all directions. 

Stimulated by these observations, Odelius et al. [73] performed molecular dynamic (MD) simulations of water adsorption at the surface of muscovite mica. They found that at monolayer coverage, water forms a fully connected two-dimensional hydrogen-bonded network in epitaxy with the mica lattice, which is stable at room temperature. A model of the calculated structure is shown in Figure 26. The icelike monolayer (actually a warped molecular bilayer) corresponds to what we have called phase-I. The model is in line with the observed hexagonal shape of the boundaries between phase-I and phase-II. Another result of the MD simulations is that no free OH bonds stick out of the surface and that on average the dipole moment of the water molecules points downward toward the surface, giving a ferroelectric character to the water bilayer. 

An extremely useful technique for measuring the amount of size applied is non-contact on-line determination of water absorption [ 194]. The moisture content of sized warps can be derived from microwave absorption by the water present. 

Figure 2 is a detail of the sloped wood cap used in Figure 1. Note that the joints are taped (at the top of the cant) and caulked (between the lead flooring and wood cant) to keep manufacturing components and product out of joints. The tape material is 3 inch wide, 2 ply, 100 percent cotton, grade B fabric with a warp and fill of approximately 78 x 78 x 72 pounds breaking strength. It should be adhesive-applied using a water insoluble nitrile rubber/ resin solution. These are commonly referred to as "Airplane Fabric" and "Pliobond 20" adhesive. The Fiberfrax Paper is used below lead flooring as an insulation barrier with a low thermal conductivity to resist heat required for installation of lead conductive floor. Note also that nonsparking nails are required. These are usually aluminum or brass.

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