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Motor Vibration and Acoustic Noise
Published in Wei Tong, Mechanical Design and Manufacturing of Electric Motors, 2022
Increasingly strict noise regulations in the United States, European Union, Japan, and China have made the development of new electric machines with low noise emission. Specifically, the European Union has set the tightest harmonized noise limits for various industrial machines, motor vehicles, household appliances, and other noise-generating products. Because of the increased awareness of the harmful effects of high industrial noise levels and government regulations that establish acceptable noise levels in the workplace, noise reduction has become an integral part of machinery safety. Noise abatement is a concern with, for example, generator-steam and gas turbine power plants. As demands for electricity increase, the power industry faces increasing challenges to build and operate efficient and quiet power generators, for example, steam turbines, gas turbines, and electrical generators.
Double-Skin Façade Concepts and Strategies
Published in Mary Ben Bonham, Bioclimatic Double-Skin Façades, 2019
Noise is unwanted sound. Noise reduction is an important strategy for occupant comfort, health, concentration, and productivity. Background noise comes from building systems, from adjacent interior spaces, and from the outside. As with other physiological factors, acoustic design begins with an understanding of a building’s intended use and its surrounding site characteristics. The acoustical performance of the interior can then be controlled through largely passive measures: siting to avoid sources of noise, use of landscape and landforms as sound barriers, interior space planning to separate quiet and noisy spaces, and strategic use of sound absorbing and reflecting interior finish materials.
Gear Unit Operation: Testing, Startup, Condition Monitoring
Published in Peter Lynwander, Gear Drive Systems, 2019
In many cases when it is determined that the noise generation of a system is excessive yet not an indication of some malfunction, the most practical method of noise reduction is the use of an acoustical enclosure. The effectiveness of such an enclosure is very dependent on eliminating all openings. Such an enclosure will also affect the ambient temperature and housing heat dissipation ability of the gearbox and means must be provided to cool the unit properly.
Construction of intelligent multi-construction management platform for bridges based on BIM technology
Published in Intelligent Buildings International, 2023
The vibration signal processing process discussed in this section includes noise reduction, transformation and envelope extraction of the vibration signal. Noise reduction methods are techniques used to reduce or eliminate unwanted noise or interference in a signal or system. Noise can come from a variety of sources, such as electrical interference, electromagnetic radiation, or physical vibrations, and can distort or mask the desired signal, making it difficult or impossible to interpret. The purpose of noise reduction methods is to improve the quality of life for individuals in a particular environment, protect equipment, and increase productivity and efficiency. It can be seen that the analog-to-digital conversion of the vibration signal has been completed by the MEMS (Microelectromechanical systems) accelerometer, and the signal processing here mainly completes the functions of noise reduction and envelope extraction of the vibration signal. MEMS are small-scale devices that integrate mechanical and electrical components, such as sensors, actuators, and microprocessors, on a single chip. They are used in a wide range of applications, from consumer electronics and automotive systems to medical devices and aerospace technology.
Pervious concrete as an alternative pavement strategy: a state-of-the-art review
Published in International Journal of Pavement Engineering, 2020
Barnali Debnath, Partha Pratim Sarkar
Noise pollution affects more than any other kind of pollution in the modern industrialised world and the prominent source of noise pollution is the sound created by road traffic. Currently, the most commonly adopted remedy for abatement of the noise generated by the traffic is the installation of sound barriers. Sound barriers obstruct the sound transmission path between vehicles and the neighbouring sides of the highways, resulting in noise reduction. But construction of such barriers leads to a costly design of pavement. Pervious concrete can achieve a great platform in modern urbanisation as the surface texture and porous nature can absorb the noise originated from the road traffic and tire pavement friction, thereby reducing the sound wave reflection (Kim and Lee 2010). According to Hendrickx (1998), pervious concrete might be used a noise absorber because the void structure in porous concrete allows the air between the tire and the pavement to escape, thereby producing a lower frequency road noise. Takao et al. (2001) have also confirmed that due to the refraction and the occurrence of interference inside the void texture, the noise energy broadcasts through the interconnected macro voids of permeable concrete, and thus get dispelled via conversion to heat. A study was carried out by Tian et al. (2014) for assessing the acoustical absorption and tire-pavement noise reduction and the study clearly verified that the pervious cement concrete could sustainably reduce the tire-pavement originated noise by 4–8 dB. Liu and Cao (2009) have also reported that single layer porous asphalt pavement significantly helped in reducing the loudness by 3.3–3.6 dB.