Abstract: A power tool including an air inlet and an inlet muffler disposed within the air inlet, the inlet muffler comprising a plurality of inlet ports, each of the plurality of inlet ports comprising a peripheral surface defining a port aperture therethrough, at least one of the plurality of inlet ports further comprising a damper material provided on the peripheral surface of the at least one inlet port and further defining the port aperture therethrough.

Abstract: An acoustic liner includes a first face sheet, a second face sheet spaced from the first face sheet, and a plurality of sidewalls extending between the first face sheet and the second face sheet. The plurality of sidewalls defines a plurality of cells. Each cell of the plurality of cells defines a cavity between the first face sheet and the second face sheet. A bulk absorber is disposed within at least one cell of the plurality of cells. The bulk absorber further defines the cavity of the at least one cell of the plurality of cells. The first face sheet defines a plurality of apertures extending through a thickness of the first face sheet. Each aperture of the plurality of apertures is aligned with a respective cell of the plurality of cells.

Abstract: Described herein is an acoustic ceiling panel comprising: a first air-permeable body comprising a first major surface opposite a second major surface and a side surface extending between the first and second major surfaces, the first body having an NRC value of at least 0.5 as measured between the first and second major surfaces of the first body; and an attenuation coating applied to the second major surface of the body and the side surface of the body, whereby the attenuation coating seals at least a portion of the second major surface and the side surface of the body.

Abstract: A centrifugal compressor includes a tubular shape casing extending in an axial direction, a motor stator fixed to an inside of the casing in a radial direction, a shaft disposed inside of the motor stator in the radial direction and extending in the axial direction, a motor rotor fixed to the shaft and facing the motor stator with a gap in the radial direction, a compression unit fixed to an end portion of the shaft on one side in the axial direction, a first thrust magnetic bearing disposed between the motor rotor and the impeller in the axial direction, and a second thrust magnetic bearing disposed on an other side in the axial direction relative to the motor rotor. A magnetic attraction force of the second thrust magnetic bearing toward the other side is larger than a magnetic attraction force of the first thrust magnetic bearing toward the one side.

Abstract: Provided are a partition member including a soundproof structure capable of efficiently insulating noise with a lightweight configuration, and an electronic device and a vehicle using the partition member. In the partition member including the soundproof structure, the soundproof structure includes a support body having an opening, and a membrane-like member that is fixed to an opening surface of the support body in which the opening is formed and that vibrates as noise is incident, and a rear surface plate fixed to the support body on a side opposite to the membrane-like member, and the soundproof structure absorbs a sound by a resonance structure formed by a rear surface space surrounded by the rear surface plate, the membrane-like member, and the support body and the membrane-like member, and insulates a sound having a frequency higher than a relative maximum resonance frequency at which a sound absorption coefficient becomes a relative maximum among resonance frequencies of the resonance structure.

Abstract: An acoustic attenuation structure includes a periodic structure having a first unit cell, the first unit cell having a first central body and a first axial tube disposed on the first central body and a second axial tube disposed on the first central body, opposite the first axial tube, each of the first axial tube and the second axial tube being in fluid communication with one another through the first central body.

Abstract: A laminated acoustic absorption member that includes at least a first fiber layer and a second fiber layer, as well as at least one substrate layer present between the first fiber layer and the second fiber layer, wherein: the first fiber layer has an average flow pore diameter of 0.5-10 ?m and a basis weight of 0.1-200 g/m2; the second fiber layer has an average flow pore diameter of 0.5-10 ?m, the average flow pore diameter of the second fiber layer being equal to or less than that of the first fiber layer, and also has a basis weight of 0.1-200 g/m2; the substrate layer has an air permeability of 40 cc/cm2·s or greater as measured by the Frazier method, and a basis weight of 1-700 g/m2; and the first fiber layer and the second fiber layer are disposed on a sound-incidence side and a sound-transmission side, respectively.

Abstract: An acoustic damper has a sound pickup unit defining a plurality of pickup unit passageways. Hollow flexible tubes are connected to exit openings of the pickup unit passageways and extend outwardly therefrom. The hollow flexible tubes and pickup unit passageways define acoustic paths.

Abstract: A compressor assembly having a high velocity muffler system which produces a particle-free compressor pump feed while reducing noise output from the compressor assembly during compressing operations. The high velocity muffler system is maintenance-free and comprises an inertia filter. The compressor assembly uses a method for producing a compressor pump feed and reducing noise during compressing operations by processing a gas through the high velocity muffler system which has an inertia filter and a muffler chamber to produce a compressor pump feed which can be compressed by a pump assembly.

Abstract: The present invention provides an automobile sound insulation panel which suitably implements a lightweight sound insulation panel with an expanded sound isolation-target frequency band and improved sound isolation performance. An automobile sound insulation panel includes a first panel member, a second panel member, and an elastic sheet member positioned between the first panel member and the elastic sheet member. The elastic sheet member includes a first projection-recess part. The first panel member abuts on respective upper opening edges of a plurality of recesses that form the first projection-recess part. Individual air layers exist between the second panel member and the elastic sheet member. A continuous air layer exists between the first panel member and the elastic sheet member.

Abstract: A sound-absorbing article (e.g., a tufted sound-absorbing article) can comprise a backing having a thickness and a plurality of face fibers associated with the backing. Optionally, the face fibers can comprise a plurality of tufts extending through the backing. The backing can define a plurality of perforations that fully extend through the thickness of the backing and are provided in a pattern to determine an acoustic property of the sound-absorbing article. Within at least a portion of the backing, sequential perforations within the pattern of the plurality of perforations can be spaced center-to-center by between 5 mm and 100 mm.

Abstract: Provided are a soundproof structure and a soundproof unit that can be reduced in size and thickness in the soundproof structure using Helmholtz resonance. The soundproof structure that includes a housing forming a space therein and having a through hole that allows the space to communicate with an outside, and generates Helmholtz resonance by the space and the through hole, the soundproof structure includes a rear surface plate disposed at a position overlapping the through hole on the space side as viewed from a penetrating direction of the through hole, in which assuming that a diameter of the through hole is ? and a distance from the rear surface plate to an opening surface of the through hole on the space side is d, d?? is satisfied and d?6 mm is satisfied.

Abstract: A stretchable multiple-layer nanocomposite material is provided and includes at least a nanocomposite material layer comprising a network of nanotubes modified with an elastomeric polymer; and at least one additional layer laminated with the nanocomposite material layer. The number of nanocomposite layers and additional layers, the nature and composition thereof, may be varied in a surface direction and/or a thickness direction so as to provide tailored mechanical and physico-chemical properties to a resulting skin that can be used to produce morphing or deployable structures.

Abstract: Provided is a soundproof structure that is small and light and can reduce a noise with a high specific frequency of a sound source at a plurality of frequencies at the same time.

Abstract: An acoustic panel for an aircraft nacelle includes, from a central axis of the nacelle to the exterior thereof, a resistive skin perforated with sound-absorbing micro-perforations, a first attenuation stage, a septum perforated with holes, a second attenuation stage, and a back skin configured to provide the mechanical strength of the acoustic panel. The septum is a planar wall having a thickness greater than that of the resistive skin, preferably greater than 4 mm. Such a panel is configured to attenuate several frequency ranges one of which being a low-frequency range, while optimizing the weight, the cost and the air intake functions. The thickness of the septum, the dimensions of the holes in the septum, the OAR of the septum and the height of the second attenuation stage are adjusted to match the mean attenuated low frequency to the vibration frequency of the aircraft engine.

Abstract: A method for manufacturing an acoustic element of a sound absorption structure including at least one cylindrical, conical or truncated conical chamber obtained from a flat preform shaped and then assembled in order to obtain the cylindrical, conical or truncated conical shape of the chamber. This manufacturing method makes it possible to obtain an acoustic element that has thin walls and is made from a material suited to its environment. An acoustic element obtained using the manufacturing method, a sound absorption structure comprising at least one such acoustic element and an aircraft powerplant comprising at least one such structure are also described.

Abstract: Provided is a soundproof structure that is small and light and can reduce a noise with a high specific frequency of a sound source at a plurality of frequencies at the same time.

Abstract: Described herein is an acoustic building panel comprising: a body comprising a fibrous material and having a first major surface opposite a second major surface and a side surface extending there-between, the fibrous material comprising polyester fiber in an amount of at least 70 wt. % based on the total weight of the fibrous material; wherein the body has a bulk density as measured between the first major surface, the second major surface, and the side surface, the bulk density ranging from about 4.8 lb./ft3 to about 6.0 lb./ft3.

Abstract: An acoustic metamaterial (AMM) passive impedance matching technique to enhance the acoustic performance of porous/poro-elastic sound absorbing materials is disclosed. An AMM passive matching device is implemented by achieving negative refractive index with double negative parameters, i.e., negative effective mass density and effective bulk modulus scheme, using various acoustic elements. The AMM technique consists of meta material architecture of acoustic inductive open tubes positioned strategically around the outside surfaces of the porous media and perforated screens inserted inside porous media to generate complex acoustic impedance load of the porous media; the inductance defined by a predetermined lengths of the open tubes. The device includes open tubes extending from the porous media to the outside ambient medium generating the desired reactive load over the broadband frequency region of the complex acoustic impedance of the porous media.

Abstract: Outflow valve assemblies for an aircraft, aircraft including an outflow valve assembly, and methods for installing an outflow valve assembly on an aircraft, are provided. In one example, an outflow valve assembly includes a louver that is movably disposed to at least partially cover an opening formed through a fuselage on an aircraft. A motor is coupled to the louver and is configured to move the louver between a closed position to obstruct fluid communication through the opening and an open position to allow fluid communication through the opening between inside and outside of the aircraft. A sound absorptive panel is disposed adjacent to the opening to attenuate noise that is generated when the louver is in the open position.