Flat-spotting

Other polyamides having higher moduli and T than nylon-6 and nylon-6,6 have been evaluated in an effort to reduce wrinkle resistance and eliminate flat-spotting of bias and bias-belted tires (Table 3). Nylons have also been tested extensively over the years for apparel and carpets (Table 4). 

In the category of industrial appHcations, nylon is the predominant fiber used in the carcass of bias tmck, racing car, and airplane tires because of its exceUent strength, adhesion to mbber, and fatigue resistance. Nylon is used less in the carcass of radial tires for automobiles and in replacement bias and bias-belted tires because of the development of temporary flat spots. For this reason, nylon has lost most of this market to polyester. 

Polyester fibers can be blended with natural fibers such as cotton and wool. The products have better qualities and are used for men s and women s wear, pillow cases, and bedspreads. Fiberfill, made from polyesters, is used in mattresses, pillows, and sleeping bags. High-tenacity polymers for tire cord reinforcement are equivalent in strength to nylon tire cords and are superior because they do not flat spot. V-belts and fire hoses made from industrial filaments are another market for polyesters. 

The technology for making single crystal ball electrodes is inexpensive and well developed [223, 224], Wire of the noble metals Au and Pt can be melted in a hydrogen oxygen flame. By careful manipulation of the flame on the ball, it can be recrystallized repeatedly to form a perfect single crystal. The crystals have a set of flat spots, [111] planes, which develop on the surface. These facets feature some of the... 

IR photothermal beam deflection spectroscopy (PBDS) and measurements of IR spectra of solids over the range 3950-450 cm l made with an interferometer coupled with a detector which senses the photothermal effect by the deflection of a laser beam are described. PBDS is a general technique and requires no sample preparation all that is needed is to hold the sample at the IR focus. The sample must have a flat spot about 2 mm in diameter accessible to the IR and laser beams. As no sample cells per se are... 

The early invesligations of viscoelasticity using silk, glass, and rubber may be extended to fibers, plastics, and elastomers, respectively. One of the early observations was that these materials undergo very slow irreversible flow or creep when subjected to stress over a long period of time. This irreversible effect is responsible for the so-called flat spots in nylon 66-rein-forced pneumatic tires. 

Dating and Sediment Accumulation. Stratigraphic Patterns Lead-210 profiles from profundal cores from each study lake show conformable declines in unsupported activity to an asymptote of supported 210Pb typically below 40-60 cm deep (Figure 3). Supported activity, attained at shallower depths in Thrush (28 cm) and Kjostad (36 cm), indicates slower linear rates of sedimentation at these sites. The activity profiles for several lakes, most notably Thrush and Kjostad, are almost perfectly exponential and thus indicate nearly constant sediment accumulation rates. Others, such as Cedar and Mountain, show flat spots and kinks that probably represent shifts in sediment flux. 

Tn the last decades many attempts have been made to obtain attractive - materials by intimate mixing of two polymers with opposite or complementary properties. For example, the impact resistance of brittle polystyrene is increased by mixing with a rubber the wettability of polyacrylonitrile fiber is increased by mixing with hydrophilic saponified cellulose acetate, and the inconvenient flat-spotting of nylon-reinforced tires is suppressed by mixing stiffer polyester fibrils into the nylon fibers. In practically all cases these products acquire their final shape via the liquid state. Thus, the viscous properties of these liquid mixtures are important. 

The white washer has a flat side on the hole through the center to maintain its nonslip position on the plug. Occasionally, the flat spot on the white washer... 

Our wheels of life, to continue the analogy of Figure 19-2, are not rolling along smoothly through our consensus reality. There are too many flat spots on the wheel that produce unpleasant jolts, and too many pieces of broken glass and potholes in the road of our consensus reality. So the ride is no longer comfortable. 

Petechia red or purple flat spots occurring on the skin as a result of hemorrhage. 

To be of any praetieal use, an object made from a polymeric material must be able to retain its shape when subjected to even small tensions or compressions over long pmods of time. This dimensional stabiUty is an important consideration in choosing a polymer for use in the manufacture of an item. No one wants a plastic telephone reedver that sags after sitting in its cradle for several weeks, or a car tire that develops a flat spot if parked in one position for too long, or clothes made from synthetic fibers that become baggy and deformed after short periods of wear. Creep tests provide a measure of this tendency to deform and are relatively easy to carry out. 

Tube wastage will often be evident and manifested as flat spots on either side of the upstream of flue gas flow, as can be seen in Figure 3.6a. A ring sample (Figure 3.6b) was sectioned from the tube for dimensional and hardness measurements. The tube had thinned significantly at two positions due to coal ash corrosion. The thinnest section of the ring (0.291 in. at the 8 00 position) was at 88% of MWT. The hardness, averaging 73 Rockwell B (RB), showed that the tube had softened after 23 years of service. 

---