Abstract: Apparatuses and methods for tuning a muffler. An apparatus comprises a housing for a muffler, a first inlet pipe, and a second inlet pipe. The housing includes a coupling chamber. The first inlet pipe has a first set of physical features and carries exhaust to the coupling chamber. The second inlet pipe has a second set of physical features and carries the exhaust to the coupling chamber. The first set of physical features varies from the second set of physical features with respect to at least one physical feature such that a first sound waveform passing through the first inlet pipe and a second sound waveform passing through the second inlet pipe are uniquely tuned to thereby tune an overall sound waveform emitted by the muffler.

Abstract: A sound absorber for an engine of an aircraft, the sound absorber comprising: a base body having a bottom plate, a wall enclosing the bottom plate and an opening enabling entry of air into the base body; and a porous tongue having a fixed end connected to the wall and a free end; wherein the tongue is porous.

Abstract: An exhaust muffler for an internal combustion engine includes a housing. A plurality of partitions are disposed within the housing, defining a plurality of chambers. An inlet pipe and an outlet pipe are also disposed within the housing and both the inlet and outlet pipes include a perforated region. The perforated region permits fluid communication between the inlet pipe, outlet pipe and the plurality of chambers. To attenuate engine noise, the perforated regions of the inlet and outlet pipes are positioned at opposite ends of the housing, forcing the exhaust gas to pass through each of the plurality of partitions and chambers, thereby damping the sound waves with minimum effect on engine back pressure levels. Alternatively, the perforated regions of the inlet and outlet pipes may be aligned in a cross-flow chamber.

Abstract: The present invention discloses a sound-absorbing piece and a preparation method thereof. The preparation method of the sound-absorbing piece comprises: preparing perforated sound-absorbing cotton matched with a preset cavity in shape; mixing sound-absorbing material powder with a solvent and a template agent to prepare a sound-absorbing slurry; impregnating the perforated sound-absorbing cotton with the sound-absorbing slurry for a preset period; and drying the perforated sound-absorbing cotton impregnated with the sound-absorbing slurry to remove a liquid in the perforated sound-absorbing cotton.

Abstract: Acoustic honeycomb structures that include cells in which a friction-locking insertion process is used to locate acoustic barriers within honeycomb cells to provide multiple degree of freedom (MDOF) acoustic liners having a variety of acoustic resonator depths. Solid polymer films are formed into acoustic barrier caps. The acoustic barrier caps are friction-locked and bonded to cell walls at one or more cell depths to form acoustically reflective hard walls that form effective bottom ends for acoustic resonators.

Abstract: An acoustic liner may include an acoustic core having an array of resonant cells, and an acoustic screen disposed across the array of resonant cells. The resonant cells include a plurality of cell walls and a resonant space defined by the plurality of cell walls. The acoustic core may include a folded acoustic core. Additionally, or in the alternative, at least some of the resonant cells may include an oblique polyhedral cellular structure and/or a multitude of sound-attenuating protuberances. The acoustic screen may include a reticulate membrane and a support lattice.

Abstract: The disclosure relates to acoustic panels and methods for preparing them. The disclosure relates more particularly to panels having a porous facing and to methods for making such panels. One aspect of the disclosure is an acoustic panel comprising a base structure. The base structure has one or more edges, an outward major surface having a total area, and an inward major surface opposing the outward major surface. The base structure has a noise reduction coefficient (NRC) of at least about 0.3. The panel includes a coating layer directly disposed on the outward major surface of the base structure, the coating layer being formed of an open-cell foam. The coating layer has an exterior major surface opposing the outward major surface of the base structure. The coating layer is substantially scattering for light in the wavelength range of 380 nm to 780 nm, and has an absorption coefficient of less than 0.5 for acoustic frequencies in the range of 100 Hz to 10,000 Hz.

Abstract: A sound absorbing body includes a cup-shaped main body and a porous sheet. The cup-shaped main body includes an opening portion and a bottom portion. The porous sheet covers the opening portion. The main body includes, between the opening portion and the bottom portion, at least one hole that is larger than pores of the porous sheet and extends through the main body.

Abstract: A sound absorbing filter for a dust collector system is attached downstream of the system air blower and ahead of the cylindrical HEPA filter cartridge. The sound filter is formed of a cylindrical barrel or shell, favorably steel, another metal, plastics, or composite with end-caps bonded on. The cylindrical shell interior is lined with plural annular layers of sound absorbing materials. The sound absorbing elements are retained with two or more thin retainer plates The lining can comprise a radial outer layer of compressed fiber batting, and a radial inner layer of convoluted acoustic polyurethane foam 1 to 2 inches thick. The foam lining protects the fiberglass from the air flow reducing fiber shedding, and also absorbs higher frequencies, with the fiberglass being more absorptive of lower frequencies.

Abstract: A two-stage water-lift and water separation muffler for use with marine electrical generators installed onboard marine vessels. A first stage water-lift muffler has internal tunable sound suppression structure to provide a first stage of exhaust silencing, and a second stage water separator having internal tunable sound suppression structure to provide a second stage of exhaust silencing while separating entrained cooling water from exhaust gases. The combined first stage water-lift muffler and second stage water separator include internal baffling and silencing structure which is easily adaptable to different generator configurations thereby allowing for structural adjustments to the muffler to optimize sound suppression and minimize backpressure for particular generator and/or exhaust conditions.

Abstract: Water impermeable, air permeable membrane assemblies are described herein. In some embodiments, the assemblies include a polymer membrane and at least one support structure. Certain assemblies are configured to provide an acoustic impedance having phase angle of +45 degrees to ?45 over a frequency range of 50 to 20,000 Hz.

Abstract: An acoustic panel is provided that includes a first skin, a second skin and a core structure. The core structure is connected to and forms a plurality of cavities between the first skin and the second skin. The cavities include a first cavity and a second cavity. The first cavity is fluidly coupled with one or more first perforations in the first skin. The second cavity is fluidly coupled with one or more second perforations in the second skin.

Abstract: A soundproof body is formed by a two-layer lamination structure of a felt layer and a film layer. Some of plural fibers constructing the felt layer are formed to be thicker than the remaining fibers.

Abstract: A method is provided for forming a structured panel. During this method, a cellular core is formed that comprises a corrugated ribbon configured with a plurality of baffles and a plurality of septums. Each of the septums extends longitudinally between and connected to a respective adjacent pair of the baffles. At least one element of the corrugated ribbon includes a structural reinforcement. The forming includes: feeding a ribbon of material between a first roller and a second roller, corrugating the ribbon of material with the first roller and the second roller to provide the baffles and the septums, and stamping the structural reinforcement into the element with the first roller and the second roller. The cellular core is bonded to a first skin. The cellular core is bonded to a second skin. The cellular core is vertically between the first skin and the second skin, and the first skin is configured with a plurality of perforations.

Abstract: A wireless power module includes a coil layer including a coil including a curved area, a wiring board disposed on the coil layer, and a plurality of conductive lines disposed on the wiring board. At least a portion of the conductive lines crosses the curved area within a predetermined angle range when viewed in a plane.

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: A panel for machinery enclosure, particularly for turbomachine enclosures. More specifically, a multilayered panel including several different layers each performing a specific function. In particular, the multilayered panel is capable to provide high levels of jet fire and fire/blast protection together with high performances in term of noise abatement with a lighter structure with respect to the panels of the prior art.

Abstract: A broadband ultrathin sound absorption or sound insulation structure controlling an acoustic wave propagation path has at least one sound absorption unit or one sound insulation unit; and each sound absorption unit or sound insulation unit has at least one acoustic wave focused section and at least one acoustic wave absorption section. The acoustic wave focused section is formed by an acoustic wave focused cavity filled with acoustic material. The acoustic wave focused section controls the acoustic wave propagation path through the change of a section of the cavity and the change of material equivalent parameters in the cavity, so that the acoustic waves are focused and propagate along the curve. The acoustic wave absorption section realizes efficient broadband sound absorption through the filled sound absorption materials and the arranged periodic local oscillators along an ultralong path of acoustic wave absorption labyrinth passage.

Abstract: A muffler for an exhaust system of an internal combustion engine includes a muffler housing (14) and at least one exhaust gas pipe group (19). The at least one exhaust gas pipe group (19) includes an outlet pipe (20) open towards an expansion chamber (26) formed in the muffler housing (14). Exhaust gas introduced via the at least one exhaust gas pipe group (19) leaves the muffler housing (16) via the outlet pipe (20). A first inlet pipe (38), of the at least one exhaust gas pipe group (19), has an inlet pipe end area (40), which is inserted into the outlet pipe (20) and extends in the outlet pipe (20). A second inlet pipe (48), of the at least one exhaust gas pipe group (19), is open towards the expansion chamber (26).

Abstract: An air duct includes a first chamber and a second chamber, the first chamber being defined between an air handling device and the second chamber, and the second chamber being defined between the first chamber and an environment exterior to the air duct, a plurality of first openings between the first chamber and the second chamber, a plurality of second openings between the second chamber and the environment exterior to the air duct, and a sound absorbing material defining at least a portion of an interior surface of at least one of the first chamber and the second chamber.