Multiple ply

Bellows can vibrate, both from internal fluid flow and externally imposed mechanical vibrations. Internal flow liner sleeves prevent flow-induced resonance, which produces bellows fatigue failure in minutes at high flow velocities. Mechanically induced resonant vibration is avoided by a bellows with a natural frequency far away from the forcing frequency, if known. Multiple-ply bellows are less susceptible to vibration failure because of the damping effect of interply friction. 

Strip packages represent an alternative form of packaging for unit-dose medication. Strips can be produced from single- or multiple-ply laminated materials provided the two inner plies can be sealed by heat or pressure (e.g., cold self-adhesive seals). Materials can range from relatively permeable plies to those that incorporate a foil ply of sufficient thickness and effectiveness of seal so that an individual hermetic seal is produced for each dosage. Strip packages are produced at lower speeds and occupy greater volume than blisters. 

Hand Lay-Up and Spray-Up. In hand lay-up, fiber reinforcements in mat or woven form are placed on the mold surface and then saturated with a liquid polymer, typically a polyester resin, that has been chemically activated to polymerize (cure) without the addition of heat. Multiple plies of reinforcement and multiple cure steps allow very heavy wall thicknesses to be achieved. 

The most efficient approach to measuring intimate contact of a multiple ply composite laminate would probably be to first use the C-scan technique or some other nondestructive method to determine the location of any flaws in the panel. The cross-sections of the panel that contain the flaws can then be examined by preparing optical micrographs of those areas, and the interply interface examined for complete contact. 

Figure 8.3 shows the distribution of multiple materials deposited on a multiple-ply nonwoven substrate. This substrate included a polymer mesh material embedded between two nonwoven layers to enhance strength. The 5.8 cm x 4.6 cm image in Fig. 8.3 shows three separate areas on the substrate where different surface composition is observed. 

Pioneering work in the development of an isocyanate-bound particleboard in the U.S. has been conducted by the Ellingson Lumber Company. This work has resulted in a proprietary process for bonding cellulosic materials with polymeric MDI to produce a multiple-ply structure panel (7.,. 8, 9.) Advantages cited for this process include a tolerance for up to 22% moisture in the wood raw material without predrying and the ability to also include significant quantities of bark and needles. 

Fibreboard kegs can be used for solid bulk drug, bulk tablet, or bulk excipient containment and transport. These are made up of multiple plies of test or Kraft liner board, convolutedly wound on a mandrel and bonded with sodium silicate adhesive between the plies. There may be an LDPE or other inside liner and the exterior may also be varnished. The base could be of either metal or plain thick board, the latter waterproofed by dipping into paraffin wax. 

Since it is sometimes difficult to identify whether a material is a single ply or a multiple ply, most students should examine a range of thinner materials to try to establish any constructional differences. However, many apparent single ply materials, e.g. biscuit, confectionery and chocolate (bar) wraps are actually multi-ply materials these frequently use a type of OPP (oriented polypropylene—especially the pearlised variety) where a special (coextruded) outer and inner heat seal ply has been added. MAP and CAP food materials are likely to have an anti-mist coating. 

Compound feed is used to eliminate inter-ply sUppage in multiple-ply sewing of thick materials, negotiating the corner of acute-angle-shaped components while top... 

Wilson et al. [3] showed that pultrusion is also applicable to other high-performance thermoplastics, in particular, amorphous polyetherimide (PEI). In this case, a wet-impregnation station for impregnating carbon fiber bundles with a PEI solution was put in line with a die system that was designed to consolidate multiple plies of prepreg tape by gradual reduction into rectangular profiles. 

In addition to the common roving strands, raw material is available in many other forms, such as preimpregnated (prepreg) and wet systems, mats (paper and nonwovens), woven specialties with knit and braided reinforcement, multiple-ply broad goods, core materials as they apply to automation, fillers, extenders, and additives (films, coatings, plating, etc). The characteristics of the reinforcement must be familiar to the machine designer. 

Table 4.4 Compatibility of Multiple Ply (Soft/Hard/Soft) Natural Rubber with Seleoted Corrodents ...

Coating two sides in one operation. This is useful when a very clean job must be performed in a multiple ply laminate only the internal ply are coated on both sides and laid onto the adhesive coats, the external plies remain uncoated. 

In conclusion, the first expectation was that using the same manufacturing techniques from previous MFC research, MFCs can be made with reinforcement orientations such that it can withstand stresses in multiple directions and that these would approximate the reinforcement effects in a traditional composite with the same orientations. MFCs can definitely be made using these techniques with essentially any fibril orientation desired, as the manufacturing process lends itself to creating MFCs with multiple plies. And as the reinforcement effects of the fibrils in MFC samples approximates the behavior of a standard fiber reinforced composite, we can therefore assume that the body of experience in the optimization of laminates can be applied to MFCs as well. 

Using multiple plies of relatively thin gauge material means that lower residual stresses are introduced when the bellows element is formed. Also, the thinner multiple plies are subjected to lower operating stresses when compared to a single heavy fabric. Bellows therefore have lower built-in and operating stresses, which ultimately results in longer life. 

FR-2 is comprised of multiple plies of paper impregnated with a flame-resistant phenolic resin. It possesses good punching characteristics and is relatively low in cost. It has typically been used in simple applications such as radios, calculators, and toys, where dimensional stability and high performance are not required. FR-3 is also paper-based, but uses an epoxy resin system. 

Single-Ply versus Multiple-Ply B-Stage Fill Considerations... 

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