Abstract: A noise muffler for an air moving device can include a housing with a housing inlet, a housing outlet, and at least a first foam component and a second foam component. The first foam component and the second foam component are placed within a cavity of the housing and define an air passageway. The first foam component and the second foam component redirect air flow through the cavity in three dimensions in order to muffle noise generated by the air moving device.

Abstract: An exhaust system noise reduction device of a vehicle enables an exhaust system to contribute to an increase in engine output while reducing engine exhaust noise. The exhaust system noise reduction device includes a muffler housing formed to airtightly surround a rear end section of an exhaust pipe; a branch pipe branched from a front end section of the exhaust pipe while having a rear end section of the branch pipe extend through the muffler housing; a barrier wall disposed at a peripheral surface of the rear end section of the exhaust pipe to divide an inner space of the muffler housing into a first chamber and a second chamber; and a punched portion formed at the rear end section of the branch pipe and disposed in the first chamber. A resonance chamber structure for reducing exhaust noise is formed in the first chamber, thereby reducing exhaust noise.

Abstract: An apparatus for speech detection is positionable on or close to a head of a speaking person. The apparatus includes an inner side and an outer side. The apparatus includes a speech detection region including a microphone. At least sections of the microphone face or form the inner side. The apparatus includes a silencer. At least part of the silencer faces or forms the outer side. The silencer has a front facing the person, a rear, and a silencer structure. At least part of the silencer structure extends between the front and the rear. The silencer includes at least one of (a) a vibroacoustic region and (b) at least in sections, a fibrous surface texture at the front with a plurality of protruding fibrous material sections.

Abstract: At least one exemplary embodiment is directed to a method of providing RF mitigation exposure to a user, more specifically an eartip that can provide RF mitigation. The eartip can be an elastic layer forming a cavity with a conductive medium within.

Abstract: Embodiments for one-way sound absorbing systems are described herein. In one example, a sound absorbing system includes a waveguide having open ends for receiving an incoming acoustic wave and wall portions defining a first port and a second port. A first electroacoustic absorber is mounted to the first port and is electrically connected to a shunting circuit, while a second electroacoustic absorber is mounted to the second port and is electrically connected to an open circuit. The sound absorption of the system is directional dependent.

Abstract: Disclosed is a muffler for a water-cooled chiller or air-cooled of a vapor-compression or absorption refrigeration system, the muffler having: an upstream case (110) having a fluid inlet (120); a downstream case (115) connected to the upstream case at a downstream end of the upstream case, the downstream case having a fluid outlet (125); the upstream case having a plurality of axially adjacent outer muffler rings (145) and a plurality of axially adjacent inner muffler rings (155), the outer muffler rings being axially coextensive and a radially exterior to the inner muffler rings and defining a fluid inlet passage (140) therebetween, wherein the outer muffler rings and inner muffler rings are a metal mesh material.

Abstract: The invention relates to a pneumatic vehicle tire (L) having at least one acoustic element (8), wherein the tire (L), fitted on a wheel rim (16), encloses with the rim (16) a space inside the tire (17), wherein the acoustic element (8) comprising a body (12) and a layer (13) is arranged on an inner tire surface (10) involved in delimiting the space inside the tire (17), wherein the body (12) is arranged on the inner tire surface (10) and wherein the layer (13) is arranged on a surface region of the body (12) that is facing the space inside the tire (17). The object is to provide a tire which has improved acoustic properties with less use of porous noise-reducing material and the acoustic element of which is more resistant to pressure changes.

Abstract: An exhaust muffler for an exhaust system of an internal combustion engine includes a muffler housing (12) with an outer shell (14) enclosing a muffler interior (22), through which exhaust gas can flow. An inner shell (54) is arranged in the muffler interior (22) and covers the outer shell (14) in at least some areas on an inner side (52) facing the muffler interior (22).

Abstract: Described hereafter is a device for the conversion of electromagnetic momentum into mechanical momentum to be used in airless environment. The device is built from rotating disk, made of non-magnetic material, on the circumference of which plurality of bar magnets are mounted. The bar magnets are in a plane which is perpendicular to the plane of the disk and in a plane, which is perpendicular to the radius of the disk that meets the centre of the bar magnet. The disk is driven by a motor that causes it to rotate. The magnets are positioned in an angle relative to the rotation axis of the disk. When the disk rotates, mechanical momentum, perpendicular to the plane of the rotating disk is generated. This momentum acts on the disk and causes it to move along the axis of rotation of the disk.

Abstract: The acoustic attenuator also serves as a protective microphone enclosure that reduces exposure to debris as well as environmental humidity 5 and harmful gases.

Abstract: A matching control method for mechanical impedance of a magnetostrictive precision transducer includes developing a three-layer neural network model corresponding to a Young's modulus of a Terfenol-D material; acquiring sample data to form a training sample set and a testing sample set; training the model using a Bayesian regularization training algorithm, and optimizing connection weights and thresholds among layers of the tested model, so as to obtain a final three-layer neural network model; based on the final model, building an inverse model of mechanical impedance of the magnetostrictive precision transducer; using a current level of impedance of a load as an input of the inverse model to obtain a bias magnetic field, and changing a level of the bias magnetic field by changing a bias current in an excitation coil of the transducer, thereby achieving adaptive matching between the mechanical impedance of the transducer and the impedance of the load.

Abstract: A sound barrier includes panels comprising a polymeric material and reinforcing inserts encased within the polymeric material; and a frame comprising posts positioned in spaced, parallel relationship and extending vertically upward, and defining inwardly-facing slots for receiving the panels. The panels are mounted lengthwise with ends within the slots and adjacent panels engage each other by tongues and grooves of lateral surfaces. Methods of making the sound barrier are provided.

Abstract: An electrical sub-assembly comprises a stator having a plurality of coils and cooling means attached to the stator. The electrical sub-assembly further comprises a plurality of pairs of diodes attached to the cooling means, each pair of diodes being in antiparallel configuration and having three electrical terminals. One of the three electrical terminals is a common terminal shared by both diodes in each pair of diodes in each pair of diodes. A plurality of busbars electrically connect each of the diodes to at least one of the plurality of coils via one or more of the electrical terminals. In use, the cooling means is configured to simultaneously cool the stator and the plurality of diodes. The electrical sub-assembly may have particular application as a part of a switched reluctance machine.

Abstract: Systems and methods for operating an engine that includes an exhaust tuning valve in its exhaust system are described. In one example, a position of the exhaust tuning valve may be adjusted to reduce a possibility of the exhaust tuning valve becoming stuck due to freezing water. In particular, the exhaust tuning valve may be cycled as ambient temperature approaches a temperature at which water freezes.

Abstract: A noise reduction apparatus can include a frame and multiple spaced apart panels positioned adjacent to each other. Each of the panels or only one of the spaced apart panel elements may have holes therein to receive acoustic waves for absorbing the waves between the panels. The panels can be attached to a frame or other connection structure so that the arrangement of panels can be hung over a work space or positioned in a work space (e.g. in a wall, formed as a partition or wall, included as part of shelving, etc.). The panels can also be incorporated into a light fixture that may hang from a ceiling or be attached to some other type of support (e.g. a table, a base, etc.). The panels can be composed of glass, wood, or other type of material.

Abstract: A muffler comprises a plurality of tubes disposed within an inner chamber. The holes are at least partially punched through the tubes so that hanging chads extend into the tubes at each hole. The tubes form a serpentine flow-path through the chamber through which exhaust flows. One or more diffusion brackets are also disposed within the chamber and downstream from one or more tube outlets.

Abstract: An MEMS microphone includes a substrate including a back volume provided inside the substrate and an opening provided at an upper surface of the substrate to communicate the back volume; a sensing device provided at an inner side wall of the back volume; a first cantilever provided inside the back volume and including end portions coupling with the sensing device; a first membrane provided at the opening; a second membrane provided inside the back volume; and second cantilevers, each of which includes a first end mechanically supporting the first cantilever, and a second end connected to the second membrane. By suspending the first cantilever on the second cantilevers, the end portions of the first cantilever always couple with a preset position of the sensing device. Thus, the DC offset of the displacement of the membrane can be prevented.

Abstract: An exhaust discharge system and method of assembling is disclosed. The exhaust discharge system may comprises an ejector tube and an exhaust stack. The ejector tube includes an outlet having an outlet cross-section. The ejector tube is configured to convey treated exhaust to the outlet. The outlet cross-section is oriented at an outlet angle to a first horizontal plane. The exhaust stack includes a first conduit and a second conduit. The second conduit includes an exit port. The exit-port cross-section is oblong in shape.

Abstract: Sound absorbing or attenuating laminate flooring materials are provided, which are directed to be used in the production of floor covering, floor panels, furniture panels, cabinets, counter-tops and wall panels. As well, the methods for producing such products are provided. In particular, abrasion resistant panels, with a laminated structure, created by forming an assembly which consists of laminating a heat-activated resin impregnated paper wear layer, a decorative layer with printed graphics or a wood veneer decorative layer, a medium density (MDF) or high-density (HDF) natural fiber-based core and a resin impregnated paper balancing layer. To achieve sound absorbing and/or attenuating properties, any or all paper layers may be pre coated with an additional flexible elastomeric coating, film or material prior to assembly of the panel, or the natural fiber core panel may be coated with a flexible elastomeric coating, film or material prior to assembly with the papers.

Abstract: A muffler includes a housing and a partition member. The housing includes a cavity, a gas inlet, and a gas outlet. The gas inlet and the gas outlet are respectively in communication with the cavity. The partition member is disposed in the housing. The partition member partitions the cavity into a resonant cavity and a muffling cavity that are isolated from each other. The resonant cavity is in communication only with the gas inlet. The muffling cavity is in communication with both the gas inlet and the gas outlet.