Acoustical Linings

Lining the inside surfaces of ducts, pipe chases, or electrical channels with sound-absorbing materials can effectively reduce the noise transmitted through such passageways. In typical duct installations, noise reductions of 10 dB/m for an acoustical lining 2.5 cm thick are well within reason for high-frequency noise. A comparable degree of noise reduction for the lower frequency sounds is more difficult to achieve because it usually requires at least a doubling of the thickness and length of the acoustical treatment. Figure 6.7.1 shows various types of duct lining baffles and silencers.

DIY Battery Repair

DIY Battery Repair

You can now recondition your old batteries at home and bring them back to 100 percent of their working condition. This guide will enable you to revive All NiCd batteries regardless of brand and battery volt. It will give you the required information on how to re-energize and revive your NiCd batteries through the RVD process, charging method and charging guidelines.

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