Search results
Results from the WOW.Com Content Network
The roof cleaning of fiberglass shingles Streaking on a roof Roof cleaning being performed using a soft-wash system. Roof cleaning is the process of removing algae, [1] mold, mildew, lichen and moss from roofs. [2] Also cleaning oxidation on metal roofs. Cleaning can extend the duration of a roof's ability to function. [2]
Mary Walton also invented a system for reducing the noise produced by the elevated railway systems that were rapidly expanding in New York City, where she lived near the Sixth Avenue Line. Walton had chosen to pursue a solution after hearing that young Thomas Edison had tried and failed. After experimentation and research, she was able to ...
Noise pollution, or sound pollution, is the propagation of noise or sound with potential harmful effects on humans and animals.The source of outdoor noise worldwide is mainly caused by machines, transport and propagation systems.
Highway noise is today less affected by motor type, since the effects in higher speed are aerodynamic and tire noise related. Other contributions to the reduction of noise at the source are: improved tire tread designs for trucks in the 1970s, better shielding of diesel stacks in the 1980s, and local vehicle regulation of unmuffled vehicles. [13]
Sound masking is an effective solution in masking intruding noise. The masking sound spectrum (National Research Council of Canada's COPE curve) is generated to be comfortable and elevated in level to be conducive to acoustical privacy in the built and occupied environment and can be specified up to 48dBA. [ 1 ]
A pair of headphones being tested inside an anechoic chamber for soundproofing. Soundproofing is any means of impeding sound propagation.There are several methods employed including increasing the distance between the source and receiver, decoupling, using noise barriers to reflect or absorb the energy of the sound waves, using damping structures such as sound baffles for absorption, or using ...
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Human activities might include voice, amplified sound systems or animal noise. Mechanical systems are elevator systems, boilers, refrigeration or air conditioning systems, generators and trash compactors. Since many of these sounds are inherently loud, the principle of regulation is to require the wall or ceiling assembly to meet certain ...