Acoustic barrier

The hydrogenated materials have a higher maximum service temperature than the conventional SBS materials and, because of the absence of double bonds in the chain, better weathering properties. Known as SEBs these materials now find use in adhesives, sealants and roofing membrane compounds. These also find use in highly filled automotive acoustic barriers and in medical, sports and leisure applications. 

An effective and environmentally friendly acoustic barrier consists of a framework of woven, freshly cut willow, filled with soil, into which the willow stems root. Variations include a soil-filled framework of dried willow, in which ground-cover plants are established. Dense, compressed reed walls designed to reduce noise are also available. 

The acoustic barrier particulate separator technology treats off-gases by means of an acoustic waveform directed against the gas flow, which causes particulates to move opposite the flow. 

The particulates drift to the wall of the separator, where they aggregate with other particulates and precipitate into a collection hopper. The acoustic barrier particulate separator differs from other separators by combining both high-efficiency and high-temperature capabilities. 

The acoustic barrier particulate separator has been tested at the pilot-scale level. Pilot-scale tests were impaired because of a design problem in the acoustic separator. Funding cnts have prevented constmction and testing of a corrected design. This technology is not cnrrently commercially available. 

Eypel A Acoustic Barrier Sheet. [Ethyl] Poly(aryloxyphosphazene) elastomer fire-resistant acoustic mass sheeting. 

HiFax. [Himont] Pdypropylene resin resins for inj. molding, extrusion, blow molding, acoustical barrier applies. 

The new FAA thermal/acoustic barrier burn-through apparatus, FAA 25.856(b) Appendix F, PartVIl. ... 

Inorganic lead compounds were used in paints and organic compoimds in fuel to increase octane number, until concerns about lead s toxic properties arose. Lead is relatively opaque to ionizing radiation and is a valuable shielding material in X-ray applications and nuclear facilities. Another market for lead is in alloys that are used as solders in applications ranging from circuit boards to heat exchangers. Lead is also used in acoustic barrier panel, glassware and ceramic, and fiber optic cables. 

AB 6023, 6053, 6103, 7023, 7103 - acoustical barrier, sound deadening, excellent processability, flexible (automotive applications isolators, fender seals, door seals). Extrusion/blow molding grades ... 

In the rapid transit industry, wherever there is an elevated structure or subway tunnel, noise and vibration caused by the vehicles can generate unrest among those living along the route. There are three areas that can be adjusted to reduce annoying frequencies the vehicles suspension system the trackbed, including the tie-to-rail interface and the floating slab and various acoustic barriers. 

FIGURE 4.102 Average noise reduction of acoustical barrier of infinite length. 

Weight savings assume increased importance in a high fuel cost environment A weight increase of 100 kg increases fuel consumption by 0.6 liters/100 km. This has stimulated the development of below-the-surface acoustic barriers... 

The classical approach to acoustic management in the floor (and other) modules has relied on a sandwich of low density and highly filled, high-density materials that imposed a substantial weight burden. The rapid rise in fuel prices in North America (2000-2001) drove the development of alternative lightweight combinations for both floor (and headliner) acoustic applications. In floor systems, these lightweight acoustic barriers are likely to find application in combination with both carpet and noncarpet surfacings. 

Polyurethane foams have made an early penetration into several acoustic barrier sectors on the basis of moldabiUty and acoustic tunabUity (Huntsman, Collins Aikman at Rover) in floor systems. 

Acoustic barriers consist of a low-density layer and a heavy (usually highly filled) layer. Glass fibers, foams, EVA, SEES compounds (injection molded), asphalt-ics, and thermoset polyurethanes are used. 

Highly filled SEES compounds at GM and DaimlerChrysler in North America (6) are currently used for injection-molded acoustic barriers in North America. This application has not grown in the European market. The broader rheology control from the newer generation of TPOs based on metallocene catalysis may have the capabiUty of enhancing the competitive position of the TPOs in this growth sector for injection molded acoustic barriers. 

R Eller. Growth opportunities for TPOs in auto interior skins, foams, and acoustic barriers. SPE Automotive TPO Global Conference, Detroit, MI October 2000. 

R EUer. Acoustic barriers—material substitution and industry structure drivers. Automotive and Transportation Interiors, 46, November 1999. 

Objects such as acoustic barrier and lamp columns located within the working width of the safety barrier can cause pocketing of vehicles, increasing the risk of injury to the occupants of errant vehicles. 

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