Tires, flat

Recycled polymeric and rubber materials can have various potential applications some of which appear technically sound and economically attractive. Among the potential products of recycled rubber from vehicle tires, flat and ribbed panels made of aggregate of these materials have been considered by several manufacturers. It has been proposed that such panels equipped with waffle plates might be used in the vertical walls which would be installed along the highways to reduce the traffic noise. 

As an example, we look at tire etching of silicon in a CF plasma in more detail. Flat Si wafers are typically etched using quasi-one-dimensional homogeneous capacitively or inductively coupled RF-plasmas. The important process in tire bulk plasma is tire fonnation of fluorine atoms in collisions of CF molecules witli tire plasma electrons... 

Figure 4 shows a fault tree for a flat tire on an automobile. The top event, the flat tire, is broken down into two immediate contributing events, road debris and tire failure. The contributing event, road debris, is a basic event. This event, which caimot be broken down into other events unless additional information is provided, is enclosed in a circle to denote it as a basic event. The other event, tire failure, is enclosed in a rectangle to denote it as an intermediate event. 

Consider again, for example, the case of the flat tire on an automobile. The initiating event in this case is the flat tire. There are two safety functions which can be defined a spare tire and an emergency road patrol. Other safety functions might be included depending on the particular situation. 

The branching is continued until all of the safety functions are considered. At this point a conclusion is reached about the result. For the flat tire example, only two results are possible the driver is either stranded or back on the road. The circle used to terminate the stranded result is given an X to denote it as an unfavorable outcome. 

The next step is to develop a method to determine the overall reUabiUty and failure probabiUty for systems constmcted of a variety of individual components. This requires an understanding of how components are linked. Components are linked either in series or in parallel. For series linkages, overall failure results from the failure of any of the components. For parallel linkages, all of the components must fad. An example of a series linkage is an automobde. The car is disabled if a flat occurs in any one of the four tires. This situation is linked in parallel to the spare tire. The car is completely disabled oidy if a flat occurs and the spare tire is flat. 

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. 

Styrene—butadiene elastomers, emulsion and solution types combined, are reported to be the largest-volume synthetic mbber, with 28.7% of the world consumption of all synthetic mbber in 1994 (38). This percentage has decreased steadily since 1973 when SBR s market share was 57% (39). The decline has been attributed to the switch to radial tires (longer milage) and the growth of other synthetic polymers, such as polyethylene, polypropylene, polyester, and polystyrene. Since 1985, production of SBR has been flat (Table 3). 

Wc rc more concerned with pressures above atmospheric pressure. For example, a flat tire on a car still has 14.7 pounds of pre.ssure inside it. We would consider this to be a flat tire because the pressure outside the tire is equal to the pressure inside the tire. We would say the tire has no pre.ssure because it would not be inflated and could not support the weight of the ear. 

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. 

Tire traction describes the force transmission between tire and road under aU eventualities. It is the prerequisite for controlled steering, acceleration, and braking of self-propelled vehicles on flat tracks. It finds its upper limit in the frictional force when total sliding occurs. Two aspects have therefore to be considered The mechanics of force transmission of elastic wheels and its relation to rubber friction. 

Tire Pressure Monitoring System for Run-Flat Tires.927... 

In order to support and meet this demand an all-around development has taken place on the material front. Increasing automobile manufacmrers requirements and ever-growing customer expectations have resulted in the evolution of new product technology. As a consequence, mn-flat tire, closed cellular polyurethane (PU) tire, tweel tire, and active wheel system have become a reality on the road today and indicate a big change in the years to come. The manufacturing technology... 

The market is still reluctant to adopt these mn-flat tires until there is an integral system that warns the driver of pressure loss. Many new smart developments are hitting the markets that monitor tire temperamre and pressure. This type of monitoring is also beneficial to fleet operators who need to measure and maintain tire-operating pressure to minimize tire wear and fuel consumption. 

FIGURE 32.9 Cross-section of a typical mn-flat tire— Michelin PAX system. 

C05-0045. Describe how the difference between an inflated and a flat automobile tire shows that a gas exerts pressure. 

A flat tire on a car is immediately obvious to the driver. However, the spare tire in the trunk might also be flat without the driver being aware.of the problem until the spare is needed. 

For instance, a flat tire on an automobile is caused by two possible events. In one case the flat is due to driving over debris on the road, such as a nail. The other possible cause is tire failure. The flat tire is identified as the top event. The two contributing causes are either basic or intermediate events. The basic events are events that cannot be defined further, and intermediate events are events that can. For this example, driving over the road debris is a basic event because no further definition is possible. The tire failure is an intermediate event because it results from either a defective tire or a worn tire. 

The flat tire example is pictured using a fault tree logic diagram, shown in Figure 11-12. The circles denote basic events and the rectangles denote intermediate events. The fishlike symbol represents the OR logic function. It means that either of the input events will cause the output state to occur. As shown in Figure 11 -12, the flat tire is caused by either debris on the road or tire failure. Similarly, the tire failure is caused by either a defective tire or a worn tire. 

Figure 11-12 A fault tree describing the various events contributing to a flat tire.

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