A resonator (1, 1′, 1″) for reducing airborne noise has at least one first ring-shaped chamber (2, 2′, 2″) arranged between an inlet piece (6, 6′) and an outlet piece (7, 7′). An inner tube (3) or inner tube pieces (4, 4″, 5) are arranged between the inlet piece (6, 6′) and outlet piece (7, 7′) and have wall apertures (18, 19, 28, 28″, 29, 29″, 30, 30″) as a connection to the adjacent ring-shaped chamber (2, 2′, 2″). The first ring-shaped chamber (2, 2′, 2″) is divided by at least one radially encircling dividing rib (13, 13′, 13″) into at least two sub-chambers (14, 14′, 14″, 15, 15′, 15″). The dividing rib (13, 13′, 13″) has a free end that, relative to the wall that is adjacent in a radial direction, forms an encircling annular space (16) for receiving an air layer that co-resonates in steady-state.

A meta atom for controlling acoustic parameters and metamaterials comprising the same, which includes a first resonator assembly having a pair of resonators configured of two resonators disposed apart from each other with respect to an axis direction; a second resonator assembly positioned inside the pair of resonators included in the first resonator assembly, and having at least one resonator; and partitions connected between the first resonator assembly and the second resonator assembly, and supporting the first and second resonator assembly.

A building element includes a sheet of a rigid material and at least one nonlinear energy sink including a blade with two end parts and a nonlinear spring function intermediate part, a mass fixed to the nonlinear spring function intermediate part of the blade, and a fixing element allowing the two end parts of the blade to be fixed to a solid support in such a way that the nonlinear spring function intermediate part can oscillate about its position of equilibrium or its positions of equilibrium. The nonlinear energy sink is fixed rigidly to the sheet by the fixing element. The building element can be contained in a partition wall. Additionally, such an energy sink or building element can be used for reducing the acoustic transparency of a wall.

Apparatus, systems, and methods for investigating a subsurface volume of interest from a borehole. Apparatus comprise an enclosure configured for conveyance along the borehole; an acoustic source in the enclosure configured to generate acoustic signals; a lens assembly disposed in the enclosure and next to the acoustic source, the lens assembly being formed of a plurality of lens elements; wherein each lens element comprises a plurality of cells arranged in a curvilinear cell array, each cell formed as a column oriented transverse to a direction of travel of the acoustical signals. The plurality of cells may be arranged according to a conformal mapping geometry, including a canonical Bipolar conformal mapping transformation of constant [u,v] contour lines to [x,y] Cartesian coordinates. A portion of the cells are scaled down in size by a scale factor. The scale factor corresponding to each cell of the portion varies non-monotonically along periodicity lines.

Low frequency alarm tones emitted by life safety devices are more like to notify sleeping children and the elderly. Disclosed herein is a life safety device equipped with a novel, compact, quarter-wave, folded resonant cavity which significantly increases the low frequency (400-700 Hz square wave) acoustic efficiency of an audio output transducer when the folded resonant cavity is acoustically coupled to the transducer forming an audio output apparatus. The folded resonant cavity is comprised of undulating, annular, acoustic passages to significantly reduce the length of the resonant cavity, thereby permitting the audio output apparatus to fit within the housing of conventional size life safety devices such as, but not limited to, residential and commercial smoke alarms and carbon monoxide alarms. Battery powered embodiments of the audio output apparatus comprising a folded resonant cavity passed audibility tests for low frequency alarm tones in smoke alarms specified by UL217.

Low frequency alarm tones emitted by life safety devices are more like to notify sleeping children and the elderly. Disclosed herein is a life safety device equipped with a novel, compact, quarter-wave, folded resonant cavity which significantly increases the low frequency (400-700 Hz square wave) acoustic efficiency of an audio output transducer when the folded resonant cavity is acoustically coupled to the transducer forming an audio output apparatus. The folded resonant cavity is comprised of undulating, annular, acoustic passages to significantly reduce the length of the resonant cavity, thereby permitting the audio output apparatus to fit within the housing of conventional size life safety devices such as, but not limited to, residential and commercial smoke alarms and carbon monoxide alarms. Battery powered embodiments of the audio output apparatus comprising a folded resonant cavity passed audibility tests for low frequency alarm tones in smoke alarms specified by UL217.

A fluidic sensing device includes a first sidewall, a second sidewall, a bulk acoustic resonator structure, a biomolecule, and a cover. A fluidic channel is defined between the first and second sidewalls. The bulk acoustic resonator structure has a surface defining at least a portion of the bottom of the channel. The biomolecule is attached to the surface of the bulk acoustic resonator that forms the bottom of the channel. The cover is disposed over the channel and the first and second sidewalls. A portion of the cover disposed over the channel defines at least a portion of the top of the channel and blocks UV radiation from being transmitted through the cover. A first portion of the cover disposed over the first sidewall is transparent to UV radiation, and a second portion of the cover disposed over the second sidewall is transparent to UV radiation.

An acoustic matching material supply device includes a frame portion that may be attachable to an ultrasonic probe that includes an ultrasonic sensor surface. The frame portion ejects an acoustic matching material. The frame portion includes an inner peripheral surface, an ejection port, an introduction port, and a flow passage. The ejection port is provided on the inner peripheral surface or in a region including the inner peripheral surface, and ejects the acoustic matching material. The introduction port receives the acoustic matching material from a device external of the frame portion. The flow passage extends between the ejection port and the introduction port, and the ejection port and the introduction port communicate with each other via the flow passage.

An acoustic matching material supply device includes a frame portion that may be attachable to an ultrasonic probe that includes an ultrasonic sensor surface. The frame portion ejects an acoustic matching material. The frame portion includes an inner peripheral surface, an ejection port, an introduction port, and a flow passage. The ejection port is provided on the inner peripheral surface or in a region including the inner peripheral surface, and ejects the acoustic matching material. The introduction port receives the acoustic matching material from a device external of the frame portion. The flow passage extends between the ejection port and the introduction port, and the ejection port and the introduction port communicate with each other via the flow passage.

In a structure for mounting resonators to a duct, the duct including openings is provided with a plurality of duct-side mounting pieces, and the resonators formed separately from the duct and including communication ports coupled to the openings are provided with a plurality of resonator-side mounting pieces that are mounted to the duct-side mounting pieces. Coupling portions of the duct and the resonators are configured to ensure turning the resonators when the resonators are mounted to the duct. On the plurality of duct-side mounting pieces disposed with intervals in a peripheral direction of the coupling portions, mounting surfaces are formed to be opposed to turning directions of the resonators when mounting the resonators to the duct, the resonator-side mounting pieces being abutted against and mounted to the mounting surfaces. Accordingly, it is possible to turn the resonators when mounting them to the duct and improve attachment work.