Traction characteristics

Typical static friction coefficients are given in Table 1. These data demonstrate that the absolute traction values for synthetic surfaces are satisfactory in comparison with natural turf, provided that shoes with the appropriate surfaces are employed. Synthetic surfaces by virtue of their constmction are to a degree directional, a characteristic which, when substantial, can significantly affect both player performance and ball roU. This effect is evident in a measurement of shoe traction in various directions with respect to the turf—pile angle. Some traction characteristics are directiy affected by the materials. 

Foi example, nylon pile fabrics, exhibiting higher moisture regain, have different traction characteristics under wet and dry conditions than do polypropylene-based materials. Effects of artificial turf fabric constmction on shoe traction ate given in Table 2. Especially effective in aiding fabric surface uniformity is texturing of the pile ribbon, a process available for the two principal pile materials nylon and polypropylene. 

Table 2. Effect of Fabric Construction on Traction Characteristics ...

Other qualities sought in a tire include ride quality, cornering ability, traction characteristics on both dry and slippery roads, tire noise, life, and cost. Addressing these qualities often opposes the objective of lower rolling resistance. 

Sipes Small individual tread voids, generally added to a tread design to improve traction characteristics. 

User-Related Properties. The most important element in the player s contact with the surface is traction. Shoe traction for light-duty consumer purposes need address only provision of reasonable footing. The frictional characteristics are obviously of much greater importance in surfaces designed for athletic use. For specialized surfaces such as a track, shoe traction is especially critical. With grass-like surfaces, traction is significantly affected by pile density and height, and other aspects of fabric constmction. 

How fast do chemical reactions occur The speed of a reaction is described by its rate. Rate is the number of events per unit time, such as the number of molecules reacting per second. Every elementary reaction has a characteristic rate. Some reactions are so fast that they are complete in the smallest measurable traction of a second, whereas others are so slow that they require almost an eternity to reach completion. The observed rate of an overall chemical reaction is determined by the rates of the elementary reactions that make up the mechanism. 

Rubber separators have good voltage characteristics, the ability to retard antimony transfer, properties to retard dendrite growth, and good electrochemical compatibility. Due to the hydrophilic properties of the rubber composition, the separators are highly wettable and renewable for the dry-charging process. Paik et al. showed that AGE-SIL (sulfur cured, hard rubber) separators performed well in industrial stationary or traction batteries. FLEX-SIL (electron-beam-cured. flexible rubber separator) separators are suited for deep-cycling batteries, and MICROPOR-... 

Reflection of acoustic waves incident on a planar interface between two isotropic media is most easily considered in terms of impedances. Acoustic characteristic impedance is defined as minus the ratio of traction to particle displacement velocity,... 

The manufacture of secondary batteries based on aqueous electrolytes forms a major part of the world electrochemical industry. Of this sector, the lead-acid system (and in particular SLI power sources), as described in the last chapter, is by far the most important component, but secondary alkaline cells form a significant and distinct commercial market. They are more expensive, but are particularly suited for consumer products which have relatively low capacity requirements. They are also used where good low temperature characteristics, robustness and low maintenance are important, such as in aircraft applications. Until recently the secondary alkaline industry has been dominated by the cadmium-nickel oxide ( nickel-cadmium ) cell, but two new systems are making major inroads, and may eventually displace the cadmium-nickel oxide cell - at least in the sealed cell market. These are the so-called nickel-metal hydride cell and the rechargeable zinc-manganese dioxide cell. There are also a group of important but more specialized alkaline cell systems which are in use or are under further development for traction, submarine and other applications. 

The characteristic feature of all Amplatzer devices is the nitinol wire mesh. There are two possible methods of implantation. Either the device is placed entirely into the appendage or the distal disc is expanded in the neck and the proximal disc in the left atrium. The risk of residual shunting around the device is increased when it is totally inserted into the LAA with no part protruding into the atrium. The Amplatzer occluder series holds the widest spectrum of device sizes (4 to 40 mm), The device is attached to a delivery cable and can simply be opened or recollapsed into the delivery catheter. Release is by unscrewing the device after first testing stability with simple traction. 

FIGURE 61.4 Histological cross sections of lymphatics (LYM) in rat skeletal muscle before (a) and after (b) con traction of the paired arcade arterioles (ART). The lymphatic channel is of the initial type with a single attenuated endothelial layer (curved arrows). Note, that in the dilated arteriole, the lymphatic is essentially compressed (a) while the lymphatic is expanded after arteriolar contraction (b) which is noticeable by the folded endothelial cells in the arteriolar lumen. In both cases, the lumen cross-sectional shape of the initial lymphatic channels is highly irregular. All lymphatics in skeletal muscle have these characteristic features. (From Skalak T.C., Schmid-Schonbein G.W., and Zweifach B.W. 1984. Microvasc. Res. 28 95.)... 

This effect of antimony sustains the use of Ph—(5—10) wt% Sb alloys for casting grids and spines for the positive plates of traction batteries intended for deep discharge cycling duties. The performance characteristics of such batteries are more stable despite the higher water loss and hence the need for maintenance. 

Tread The wear resistance component of the tire in contact with the road. It must also provide traction, wet skid, and good cornering characteristics with minimum noise generation and low heat buildup. Tread components can consist of blends of natural rubber, polybutadiene (BR), and styrene-butadiene rubber (SBR), compounded with carbon black, silica, oils, and vulcanizing chemicals. 

Rib designs with design elements principally in the circumferential direction are the most common type of tread pattern and show overall good service for all-wheel-position summer service. On heavy tmcks, they are used nearly exclusively on steer and trailer axles because of their lateral traction and uniform wear characteristics. Rib/lug combinations tend to find use on all-season tires, which require a balance of good tread wear, traction, and wet skid. On heavy-duty truck drive axles, where forward traction is a prime requirement and where fast tread wear occurs as a result of torque-induced slip, the highway lug design is required. For off-highway service conditions the tread pattern assumes a... 

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