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Noise, vibration, and harshness (NVH), also known as noise and vibration (N&V), is the study and modification of the noise and vibration characteristics of vehicles, particularly cars and trucks. While noise and vibration can be readily measured, harshness is a subjective quality, and is measured either via jury evaluations, or with analytical ...
Subway systems, light rail transit and freight trains can send loud train noise into neighborhoods. Organizations such as the World Health Organization [1] and the U.S. Environmental Protection Agency have set guidelines for noise level decibel limits for rapid transit. Noise levels can be reduced by installing noise barriers next to the track. [2]
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]
An additional study examined the impact noise exposure had on the Indo-Pacific humpbacked dolphin (Sousa chinensis). The dolphins were exposed to elevated noise levels due to construction in the Pearl River Estuary in China, specifically caused by the world's largest vibration hammer—the OCTA-KONG. [61]
Noise measurement can also be part of a test procedure using white noise, or some other specialized form of test signal.In audio systems and broadcasting, specific methods are used to obtain subjectively valid results in order that different devices and signal paths may be compared regardless of the inconsistent spectral distribution and temporal properties of the noise that they generate.
Environmental noise is an accumulation of noise pollution that occurs outside. This noise can be caused by transport, industrial, and recreational activities. [1] Noise is frequently described as 'unwanted sound'. Within this context, environmental noise is generally present in some form in all areas of human, animal, or environmental activity.
Noise-induced hearing loss is a permanent shift in pure-tone thresholds, resulting in sensorineural hearing loss. The severity of a threshold shift is dependent on duration and severity of noise exposure. Noise-induced threshold shifts are seen as a notch on an audiogram from 3000 to 6000 Hz, but most often at 4000 Hz. [16]
Some negative consequences are increases in noise level, loss of wetlands, adverse impacts to historic sites, gentrification, and risk of displacement. [6] A 2011 study done by Human Impact Partners in Minnesota showed that light rail and RTD expansion in their communities had at least one if not all of these negative outcomes: higher rate of residential and business displacement, increase in ...