Prolonging the life

The next significant strength improvement followed the 1950 Du Pont (19) discovery of monoamine and quaternary ammonium modifiers, which, when added to the viscose, prolonged the life of the ziac cellulose xanthate gel, and enabled even higher stretch levels to be used. Modifiers have proliferated siace they were first patented and the Hst now iacludes many poly(alkylene oxide) derivatives (20), polyhydroxypolyamines (21—23), and dithiocarbamates (24). 

One of the primary factors in the deterioration of a pavement stmcture is the intmsion of surface water into the support stmcture of the pavement. When rehabihtating a pavement, the installation of a moisture barrier between the old, existing pavement surface and the new overlain surface acts to retard moisture intmsion, thus prolonging the life of the overlay. 

Cotton cloths are sometimes treated with metallic salts (copper sulfate) to improve their corrosion-resistant qualities. Such cloths are in the usual cotton filter cloth grades, and while they are not equivalent to metallic cloths, the treatment does materially prolong the life of the cotton fiber. When dealing with metallic cloths, the following terms are important ... 

The preservation processes should be designed to prolong the life of the product by inhibiting the effect of natural elements. While the conditions in the factory can be measured, those outside the factory can only be predicted. Markings on packaging are therefore essential to warn handlers of any dangers or precautions they must observe. 

A cylinder liner such as that shown in Figure 11-6 may be used to help prolong the life of the cylinder and improve operating flexibility. Any dtunage caused by the action of the piston or heat generated by compression will affect the cylinder liner, which may be removed and replaced. As the surface of the liner wears, it is much easier and quicker to repair it than to repair the cylinder itself. In addition, liners enable the diameter of the piston to be varied without changing the cylinder and thus provide flexibility to respond to different conditions of pressure and flow rate. 

Where a high cleaning efficiency is required it is sound practice to install a filter of lower performance upstream to trap the larger particles and prolong the life of the more expensive High Efficiency Particulate (HEPA) Air Filter. Two filters of equal merit placed in series will not be materially more efficient than one. 

The hardness of an enamel surface is an important property for such items as enamelled sink units, domestic appliances, washing machine tubs which have to withstand the abrasive action of buttons, etc. On Moh s scale most enamels have a hardness of up to 6 (orthoclase). There are two types of hardness of importance to users of enamel, viz. surface and subsurface. The former is more important for domestic uses when one considers the scratching action of cutlery, pans, etc. whereas subsurface hardness is the prime factor in prolonging the life of enamelled scoops, buckets, etc. in such applications as elevators or conveyors of coal and other minerals. 

Further reduction of the calorific value of nitroglycerine powder proved to be impossible. But by using nitrodiglycol instead of nitroglycerine, a powder was obtained with a heat of explosion of 690 kcal, which prolonged the life of the barrel considerably, i.e. to 15,000-17,000... 

The payoff to society from greater attention to the surface and interfacial engineering of concrete is potentially immense high-tech concretes that will prolong the life of public works and reduce their maintenance costs as well as dramatic new applications for this old reliable material. 

Prolonging the life of solutions reduces the additional investment of fresh process solutions and time... 

The Catalysis approach to design is about standing back from the detail so that you can discuss the most important parts without the clutter of line detail. You prolong the life of a design by making your overall vision clear to maintained, enhancers, and extenders. Earlier in this book we saw how to use models to abstract away implementation details. Pre/ post specifications abstracted what was required of an object rather than how it achieved it. Joint actions represent, as one thing, an interaction that may be implemented by a series of messages. 

Another requirement is a reduction in the generation of heat. Operation of any membrane under 90°C, even at 8 kA m-2, is very much desired for safety reasons and to prolong the life of the cell, piping or any other facilities subjected to high temperature. The ohmic drop beyond the membrane has been previously lowered by the narrowed gap separating the electrodes. This leaves further reduction of the ohmic resistance of the membrane to be achieved. 

In any case, the use of these catalytic systems will depend on their stability. In fact, the still unresolved problem with the application of these catalysts to industrial processes is whether to prolong the life of the catalyst or to continuously regenerate the catalyst in an efficient way. 

With the exception of leurosine, all three alkaloids significantly prolonged the life of animals infected with the PI534 leukemic cell line. This effect was observed even when treatment was delayed until the animals were nearly moribund. However, and perhaps most interestingly, it was observed that cured animals were resistant to additional challenges with this tumor line (i). Sadly, these results could not be extrapolated to clinical situations. 

Zidovudine has been authorized for treating patients with AIDS. It significantly prolongs the life of the patient, although it has a number of toxic effects. Synonyms of this drug are azidothymidine and retrovir. 

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