UNDER INFLATION

Tip To avoid tensions in the repair bonding, repair under inflated conditions is recommended. 

Deliberate or accidental misuse is generally a fault on the part of the user - he or she is rather less likely to understand the material and its capabilities - but the supplier does need to make the limitations of the product known. The public has blind faith in tyres miming under-inflated and probably a high percentage of tyre problems are self inflicted. 

Premature failure of tyres was thought to be mainly a result of running at under-inflation pressure. Load tests of 9.00-20 16PR and 9.00R20 16PR tyres at different inflation pressures were carried out. The results obtained showed that the effect of under-inflation was equivalent to that of overload. The combination of overload and under-inflation would result in fatal damage to the tyre. 

Pneumatic tyre structure mechanics were analysed using non-linear finite element analysis. The deformation and stress-strain of all the components under inflation pressure of the tyre were predicted and the effects of three different bead structures on tyre performance were studied. It was found that stress concentration was the main cause of bead burst, separation and wear and that the tendency of the tyre to undergo early damage increased with decrease in bead rigidity. The study showed that the finite element method was an effective means of optimising tyre structure. 7 refs. 

NOTE Measure tire air pressure only if there is evidence the tire is under-inflated. 

Inflated Diaphragm Method (ASTM D3886). This method is appHcable both to woven and knitted fabrics. The specimen is abraded by mbbing either unidirectionally or multidirectionally against an abradant having specified surface characteristics. The specimen is supported by an inflated mbber diaphragm under a constant pressure. Evaluation of abrasion resistance can be either by determination of the number of cycles required to wear through the center of the fabric completely or by visual examination of the specimens after a specified number of cycles. 

The true rates of return L can be calculated from Eq. (9-116) to be 20, 9.09, 0, and —7.69 percent respec tively for generaf inflation rates of 0, 10, 20, and 30 percent. Thus, although the time required for a projec t with a payback period of 4 years to reach a nominal (DCFRR) of 20 percent is reduced from almost 9 years under conditions of no inflation to less than 3V2years for 30 percent inflation, the true rate of return that prevails for the latter condition is —7.69 percent, implying that the project loses money in real terms. 

The usual estimating technique is to collect equipment pricing information from other projects and correlate this data by size, weight, pressure rating, and/or materials of construction. Each piece must be adjusted for inflation to bring all costs to one base time. Adjusting costs for inflation is discussed later under the heading, " Construction Cost Indexes. ... 

There is now an immense range of scientific Journals, broad, narrow and in-between, to serve the great range of materials. The journals published by the many professional societies have encountered increasing competition from the many published by commercial publishers, but those, in turn, are now under severe pressure because of a growing librarians revolt against subscription prices that rise much faster than general inflation. 

Another useful reagent for the preparation of alkynyl lodonium Inflates is [cyano(trifluoromethylsulfonyloxy)(phenyl)]iodine [/i7, 138, 139, 140] prepared from iodosobenzene, trimethylsilyl tnflate, and trimethylsilyl cyanide (equation 71). This reagent reacts with various stannylacetylenes under very mild conditions to form the corresponding alkynyl iodonium salts in high yields [139] (equation 72)... 

About two-thirds of the N2 produced industrially is supplied as a gas, mainly in pipes but also in cylinders under pressure. The remaining one-third is supplied as liquid N2 since this is also a very convenient source of the dry gas. The main use is as an inert atmosphere in the iron and steel industry and in many other metallurgical and chemical processes where the presence of air would involve fire or explosion hazards or unacceptable oxidation of products. Thus, it is extensively used as a purge in petrochemical reactors and other chemical equipment, as an inert diluent for chemicals, and in the float glass process to prevent oxidation of the molten tin (p. 370). It is also used as a blanketing gas in the electronics industry, in the packaging of processed foods and pharmaceuticals, and to pressurize electric cables, telephone wires, and inflatable rubber tyres, etc. 

If an elastomer is bonded to a substrate such as steel, it is usual for the bond to have small areas of imperfection where the adhesive or the chemical preparation of the surface is defective. Such areas are known as holidays. In high-pressure gas environments, these holidays form nucleation sites for the growth of half-bubbles or domes, under conditions where gas has been dissolved in the elastomer and the pressure has subsequently been reduced. Gas collecting at the imperfection at the interface will inflate the mbber layer, and domes will show as bumps on the surface of the mbber-coating layer—just as a paint layer bubbles up in domes when the wood underneath gives off moisrnre or solvents in particular areas. 

The extrusion blow molding cycle is illustrated in Fig. 14.2. The extrusion component of the cycle is normally continuous. As soon as one length of parison has been captured by the mold, another length starts to form. To allow room for a new length of parison to emerge from the die, the mold moves aside as soon it has captured a parison and the knife has severed it. The mold is rapidly translated to a remote blowing station where inflation takes place. After the product is ejected, the open mold moves back under the die where it surrounds and captures another length of parison. 

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