Light-Weight

The polycondensation of di-isocyanates with polyhydric alcohols gives a wide range of polyurethanes which are used as artificial rubbers and light-weight foams, and have other important properties. Isocyanates are also used as modifiers in alkyd resins. ... 

Used as a light-weight aggregate in heat and sound insulating plasters, as a loose fill and in... 

Although its electrical conductivity is only about 60% that of copper, it is used in electrical transmission lines because of its light weight. Pure aluminum is soft and lacks strength, but it can be alloyed with small amounts of copper, magnesium, silicon, manganese, and other elements to impart a variety of useful properties. 

In the sheeting market, the low density polyethylenes are less important than the high density resins. The high density resins have excellent chemical resistance, stress-crack resistance, durabiUty, and low temperature properties which make them ideal for pond liners, waste treatment faciUties, and landfills. In thicker section, HMW-HDPE sheet makes good containers, trays, tmck-bed liners, disposable items, and concrete molds. The good durabiUty, abrasion resistance, and light weight are critical elements for its selection. 

The light weight of these products reduces user s shipping costs and conserves energy in transportation. These products are reusable, a key property from economic, ecological, and energy conservation standpoints. Most products are available in bulk densities of 4.0 to 4.8 kg/m (0.25 to 0.30 lb/fT). Average price is about 1.50 per pound from the manufacturer. 

Draperies. Draperies of light weight or open-weave fabrics are ineffective for sound-absorbing purposes. Heavy draperies, such as flannel and velour, can provide useful sound absorption if properly installed. For best results they should be hung with 100% fullness, ie, 2 nC for every nC of wall or window surface covered. The sound-absorbing properties also are affected by the amount of space between the draperies and the surface behind them. 

The most important appHcation of fiber-optic laser-based communication is in long-distance telecommunications (92,93). Fiber-optic systems offer very high capacity, low cost-per-channel, light weight, small size, and immunity to crosstalk and electrical interference. 

This invention relates generally to light weight covers used to increase the aerodynamic properties of wheels. More specifically, the present invention relates to covers for wheels capable of creating an aerodynamic effect by reducing the friction or drag across the surface of a wheel created by air flow. 

The present invention provides a wheel cover which improves the aerodynamic properties of the hub-rim-spoke wheels. The wheel cover of the present invention is preferably made of a light weight synthetic or natural polymer, fabric or paper film which is adhesively applied to a wheel through simple manual application. In turn, the aerodynamic wheel cover of the present invention may also be easily removed and replaced to allow on-road repairs of spoke, hub, or rim. 

The deck may be nailable, eg, wood or light weight concrete, or not, eg, steel or stmctural concrete. The felts or mats may be organic (cellulose), or fiber glass. The roof slope ranges from dead level (0—2.1 cm/m), to flat (2.1—12.5 cm/m), to steep (12.5—25 cm, /m). 

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