sound absorbing Articles
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Acoustical characterisation of porous sound absorbing materials: a review
Over the past 50 years, the characterisation of porous sound absorbing materials has been of increasing interest to both the acoustic engineers and customers. It is particularly important that acoustic engineers are able to predict the acoustical behaviour of these materials to get a quantitative measure of the acoustic energy absorption. This paper reviews the relevant literatures over this ...
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Dissipative expansion chambers with two concentric layers of fibrous material
The acoustic performance of a dissipative expansion chamber lined with two concentric, annular layers of fibrous material with different resistances is investigated. A two-dimensional analytical approach is used to determine the transmission loss of this dissipative silencer. From the boundary conditions at the rigid wall, and the interfaces between the fibre layers and the central airway, the ...
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Asphalt in rubber
Rubber Asphalt In Italy it is still little known, although it has already been used in 27 provinces. But in other European countries it has already covered several kilometers of roads and in the United States it has been used for at least 15 years. We're talking about rubber asphalt. A modified bituminous mixture compared to traditional asphalt, in which the rubber powder is the protagonist. ...
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A Brief Description of the Fully Refined Paraffin Wax
Performance characteristics The fully refined paraffin wax manufacturers in China Also called pure white wax, fully refined paraffin wax appearance is white solid, there are massive and granular products. Its products high melting point, oil content, less not cohere at room temperature, no sweat, no greasy feeling, waterproof, moistureproof and good electrical insulation. Due to the delicate and ...
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How to choose the best generator
Buying a generator for your business is an important investment. Unfortunately many customers think that buying the famous combo Perkins, Stamford, Deep Sea you can make the best deal of your life by buying the product with the lower price, because “anyway they are the same”. However, we must not forget that there are also cables, wirings, connections, terminals, the type of ...
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Elastic sound absorption theory of fibrous material
Because of the complexity of classical sound absorption theory's expressions, it is difficult to obtain physical insight into the acoustic behaviour of porous materials and to determine the dominant mechanism for sound absorption for a given material at a given frequency. Alternatively, there are very simple expressions. A new theory has been put forward that fibrous material absorbs sound by the ...
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Measuring level by weight
Measuring level or inventory by weight provides high accuracy. The weight is not affected by ingredients that foam or settle unevenly or by changes in density or the shape of the tank. Weight is weight, regardless of percent solids, bridging, rat-holing, or whether your ingredient is conductive or sound-absorbing. Because weighing is a noncontact method of measuring level, there is no chance of ...
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Reducing noise levels through engineering controls
It"s fairly easy to control personal exposure to noise by limiting exposure time or using hearing protectors like ear plugs or ear muffs. Engineering controls are usually applied to the machinery that produces noise. Imagine a 200 foot x 175 foot manufacturing facility with a 30 foot high ceiling. In this building are a variety of cut-off saws, grinders, millers and other metal-working ...
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What Is the Difference Between Fully Refined Paraffin Wax and Semi-refined Paraffin Wax? What Is It
What is fully refined paraffin wax? The fully refined paraffin wax manufacturer in China Jinyu international will introduce it for you. Fully refined paraffin is also called refined white wax. Its products have high melting point, low oil content, no adhesion, no sweat, no greasy feeling, good waterproof, moisture-proof and electrical insulation at room temperature. It has deep refinement, low ...
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Reducing Noise Levels through Engineering Controls
It’s fairly simple to control personal exposure to noise by limiting exposure time or using hearing protectors like ear plugs or ear muffs. Engineering controls are usually applied to the machinery that produces noise. OSHA regulations state that if noise exposure levels reach the 90dba PEL, then engineering controls must be pursued. Thus effort must be instituted to identify means to ...
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The difference between concrete pump and mortar sprayer
What is a concrete pump? The small concrete pump, also known as a concrete conveying pump, is a device often used in construction projects for conveying concrete materials. It is a device that conveys concrete maps through pipes and can carry out water bottles or pour concrete vertically. Its working principle is that the motor drives the oil pump to generate pressure to drive the oil cylinder. ...
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Noise Cancelling Headphones: The Beginning
Noise cancelling headphones make it possible for people to listen to audio content without having to raise the volume excessively. The special headphones can totally offset the effects of a distracting noise, enabling the wearer to relax in a noisy environment, such as when they’re travelling on an aircraft, for example. Who invented the headphones? Dr Lawrence Jerome Fogel, an American ...
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What is reverberation time and how it is calculated?
What is the reverberation time of a room? Reverberation time is the time required for the sound to “fade away” or decay in a closed space. Sound in a room will repeatedly bounce off surfaces such as the floor, walls, ceiling, windows or tables. When these reflections mix, a phenomeon known as reverberation is created. Reverberation reduces when the reflections hit surfaces that can ...
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Recreation Management – Problem Solver: Control Noise in your Natatorium or Gym
Natatoriums and gymnasiums often play host to multiple types of programs. But with inherently poor acoustics, the noise level becomes a nuisance. The right attention to engineering and design can ameliorate the problem. Q: We're building a natatorium and would like to host multiple types of events, but we're concerned about the acoustics. What should we know? A: The typical materials used to ...
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Personal Ear Protection – PPE for noise at work
Personal Ear Protection – the last resort PPE should always be regarded as a ‘last resort’ to protect against risks to safety and health in the workplace. The provision of personal hearing protection is no different. You may find resistance from your workforce using them and they can be costly to maintain and replace. They can also interfere with communications, more ...
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Noise Control By Engineering Methods
Noise Exposure Levels The OSHA Noise Standard (29CFR1910.95) states when the 8-hour noise exposure exceeds 90 dB-A, an effort to control noise through engineering methods must be attempted if the 90 dB-A levels are exceeded. Hearing Protection Hearing protection alone is not an acceptable means of permanent OSHA compliance with the noise standard. The reason is simple, the poorest means of ...
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Noise Reduction Techniques for Laboratory Fume Hoods
Laboratory fume hoods are crucial for maintaining a safe and controlled environment in scientific research facilities. However, the noise generated by fume hoods can often disrupt concentration, hinder communication, and affect the overall well-being of laboratory personnel. By utilizing these comprehensive strategies for effectively reducing noise in laboratory fume hoods, laboratories can ...
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Rockwool Sandwich Panel
Overview Rock Wool sandwich panel is usually used for wall and ceilings, which has certain requirements for fire resistance. In addition, it has very good thermal insulation properties. Thus, most of customers like the rock wool sandwich panels. Rockwool sandwich panels are commonly used in clean room engineering in electronics and pharmaceutical plants. Rock wool is a kind of inorganic fiber ...
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Noise control in building design planning is a sound investment
Jochen Schaal, managing director of SoundPLAN GmbH and Michel Rosmolen, director of SoundPLAN Asia, outline developments in room acoustics to improve our environment Demand for architectural services in India is increasing, with government initiatives like the Smart Cities Mission[i], encouraging development in the sector. This project aims to harness technology to improve urban development, ...
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Environmental Considerations for Rubber-Tired Gantry Cranes
In an era where sustainability and environmental consciousness are at the forefront of industrial decision-making, the adoption of eco-friendly technologies becomes paramount. Rubber-tired gantry cranes (RTGs), commonly used in container terminals for efficient cargo handling, are no exception. This article explores the environmental considerations associated with rubber-tired gantry cranes and ...
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