Abstract: A multi-mode heat transfer system includes an emitter device with an inner core surrounded by an outer core having an outer surface and an emission surface disposed on the outer surface. The emission surface includes a thermal metamaterial configured to direct heat from the inner core in at least two desired directions to an object other than the emitter device. The object can include a thermal receiver devices, for example two receiver devices and the emission surface can direct heat to two different receiver devices spaced apart from the emitter device.

Abstract: A duct includes a duct body defining an inlet, an outlet, and a channel connecting the inlet and the outlet. The duct body also defines an upstream resonator. The upstream resonator includes an upstream annular cavity external to the channel and an annular perforated plate coplanar with the upstream annular cavity. The duct body further defines a downstream resonator. The downstream resonator includes a downstream annular cavity external to the channel and an annular neck coplanar with the downstream annular cavity.

Abstract: A sound absorbing device includes a panel with an opening, a duct extending from the panel and in fluid communication with the opening, and a plurality of acoustic resonators embedded in the panel and in fluid communication with the duct. The duct can have a rectangular cuboid shape and the plurality of acoustic resonators can include a first subset of quarter-wavelength tubes extending from a first planar side of the duct, a second subset of quarter-wavelength tubes extending from a second planar side of the duct, a third subset of quarter-wavelength tubes extending from a third planar side of the duct, and a fourth subset of quarter-wavelength tubes extending from a fourth planar side of the duct. Also, the second subset of quarter-wavelength tubes and the fourth subset of quarter-wavelength tubes can have mirror symmetry with the first subset of quarter-wavelength tubes and the third subset of quarter-wavelength tubes, respectively.

Abstract: Systems and methods for determining the incident angle of an acoustic wave are presented herein. One embodiment receives an acoustic wave at N transducers, where N is a natural number greater than or equal to 2; solves a set of N coupled differential equations modeling a set of N virtual coupled acoustic resonators using N coupled analog circuits, wherein each of the N coupled analog circuits receives an output signal from a unique one of the N transducers and outputs a voltage signal; and analyzes the N voltage signals output by the N coupled analog circuits to produce an estimate of the incident angle of the acoustic wave.

Abstract: A flexural wave absorber includes an L-shaped cantilever beam lossy acoustic black hole disposed on a surface of a mechanical structure and an L-shaped cantilever beam lossless acoustic black hole disposed on the surface and spaced apart from the L-shaped cantilever beam lossy acoustic black hole a predefined distance. The L-shaped cantilever beam lossy acoustic black hole and the L-shaped cantilever beam lossless acoustic black hole, in combination, are configured to asymmetrically absorb a plurality of different frequencies of flexural waves within at least a 2000 Hz frequency band acting on the mechanical structure. The L-shaped cantilever beam lossy acoustic black hole and the L-shaped cantilever beam lossless acoustic black hole can both include a projecting beam with an outer surface or an inner surface having power law profile.

Abstract: A sound absorbing device includes a chamber with an opening and at least one fabric layer extending across the opening. The at least one fabric layer extending across the opening is at least two fabric layers stacked relative to and in direct contact with each other, at least two fabric layers stacked relative to and spaced apart from each other by a predefined distance, at least one elastic fabric layer configured to vibrate independently from the chamber, or a three dimensional fabric layer. The at least two fabric layers stacked relative to and in direct contact with each other and the at least two fabric layers stacked relative to and spaced apart from each other by a predefined distance are configured to move relative to each other, and the at least one elastic fabric layer is configured to vibrate independently from the chamber.

Abstract: A flexural wave absorber includes a metasurface with an inner portion, an outer portion, and a plurality of beam strips extending between the inner portion and the outer portion. The metasurface also includes a plurality of coupled resonators disposed on the plurality of beam strips. The plurality of coupled resonators can include a lossy resonator and a lossless resonator, two lossy resonators and a lossless resonator, or a lossy resonator and two lossless resonators. In addition, each of the plurality of beam strips can have multiple pairs of coupled resonators disposed thereon that work at or absorb different frequency ranges.

Abstract: A duct includes a duct body defining an inlet, an outlet, and a channel connecting the inlet and the outlet. The duct body also defines an upstream resonator. The upstream resonator includes an upstream annular cavity external to the channel and an annular perforated plate coplanar with the upstream annular cavity. The duct body further defines a downstream resonator. The downstream resonator includes a downstream annular cavity external to the channel and an annular neck coplanar with the downstream annular cavity.

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: A sound absorber can include a housing including a back wall, a perimeter wall, and an interior wall that form cells having cavities. The sound absorber can also include a panel disposed on the housing that substantially faces the back wall and encloses the cavities of the cells. The panel can define groups of holes for each cell such that one group of holes extend though the panel to the cavity of one cell and another group of holes extend through the panel to the cavity of another cell.

Abstract: Described is a system for transmitting a flexural wave acting on one structure to another structure. In one example, a system includes a first structure having a first property and a first end and a second structure having a second property and a second end connected to the first end of the first structure. The first property is different from the second property and may be related to the material and/or geometric properties of the first and second structures. A mechanical resonator is connected to the first structure at a distance from the first end of about a quarter-wavelength of the frequency of a flexural wave acting on the first structure. The mechanical resonator matches a first mechanical impedance of the first structure to a second mechanical impedance of the second structure to allow high transmission of the flexural wave acting on the first structure to the second structure.

Abstract: A wave control system includes a substrate with a plurality of beams spaced apart from each other, a plurality of sensors disposed on the plurality of beams, a plurality of actuators disposed on the plurality of beams, a processor, and a memory communicably coupled to the processor. The memory stores machine-readable instructions that, when executed by the processor, cause the processor to determine a frequency of a fundamental incident wave propagating within and/or incident on the plurality of beams based on a plurality of signals from the plurality of sensors, and control the plurality of actuators to generate at least one of a cancellation wave, a subharmonic wave, and a superharmonic wave, based on the frequency of the fundamental incident wave. In addition, a reflected fundamental wave, the sub harmonic wave, and/or the superharmonic wave can be steered to a desired direction or path along the substrate.

Abstract: Embodiments described herein relate to a bi-functional thermal cooling system. The bi-functional thermal cooling system includes a first body, a second body, and a third body. The second body has a first plurality of Weyl semimetal nanostructures. The second body is spaced apart from the first body. The third body has a second plurality of Weyl semimetal nanostructures. The third body is spaced apart from the second body. The second body and the third body are each configured to independently rotate with respect to the first body to change an optical property of the first plurality of Weyl semimetal nanostructures of the second body and an optical property of the second plurality of Weyl semimetal nanostructures of the third body.

Abstract: Embodiments described herein relate a tunable heat transfer system. The tunable heat transfer system includes a controller, a first body, and a second body. The first body is communicatively coupled to the controller. The second body is communicatively coupled to the controller and spaced apart from the first body. The second body has a plurality of semimetal layers and a dielectric portion positioned between each of the plurality of semimetal layers. Each of the dielectric portions has a thickness to define a gap between each the plurality of semimetal layers in an expanded state and permitting each of the plurality of semimetal layers to abut each other in a contracted state. The controller is configured to change a near-field radiative heat transfer between the first body and the second body by changing the thickness of each of the dielectric portions between the expanded state and the contracted state.

Abstract: A device for superscattering a target acoustic wave may include a body having an outer surface, at least one resonator being defined within the body and extending to an opening defined within the outer surface and configured to cause the superscattering of the target acoustic wave impinging upon the body, and a motor connected to the body and configured to selectively rotate the body.

Abstract: Systems and methods for determining the incident angle of an acoustic wave are presented herein. One embodiment receives an acoustic wave at N transducers, where N is a natural number greater than or equal to 2; solves a set of N coupled differential equations modeling a set of N virtual coupled acoustic resonators using N coupled analog circuits, wherein each of the N coupled analog circuits receives an output signal from a unique one of the N transducers and outputs a voltage signal; and analyzes the N voltage signals output by the N coupled analog circuits to produce an estimate of the incident angle of the acoustic wave.

Abstract: Systems and methods for virtually coupled resonators to determine an incidence angle of an acoustic wave are described herein. In one example, a system includes a processor and first and second transducers in communication with the processor. The first transducer produces a first signal in response to detecting an acoustic wave, while the second transducer produces a second signal in response to detecting the acoustic wave. The system may also include a memory in communication with the processor and having machine-readable instructions that cause the processor to modify the first signal and the second signal using a virtual resonator mapping function to generate a modified first signal and a modified second signal. The virtual resonator mapping function changes the first signal and the second signal to be representative of signals produced by transducers located within a hypothetical chamber of a hypothetical resonator.

Abstract: Embodiments described herein generally relate to a multi-mode heat transfer system. The heat transfer system includes an emitter device. The emitter device includes an inner core surrounded by an outer core having a thickness and an outer surface. A composite material pattern extends through at least a portion of the outer surface and at least a portion of the thickness of the outer core and is thermally coupled to the inner core. The composite material pattern in combination with an optimized emissivity surface coating/paint profile directs a heat from the inner core to an object other than the emitter device.

Abstract: Described are systems for absorbing flexural waves acting on a structure. In one example, the system includes a first resonator connected to a structure at a first location and a second resonator connected to the structure at a second location. The distance between the first location and the second location is based on a frequency of a flexural wave acting upon the structure and an orientation of the first resonator and the second resonator with respect to each other.

Abstract: The present invention features a novel design for a bolometric infrared detector focused on LWIR range for human body high-resolution temperature sensing. The present invention incorporates an efficient plasmonic absorber and VO2 nanobeam to facilitate improvement in both aspects—thermal resolution and spatial resolution. The present invention significantly improves the detectivity, NETD, and responsivity for a smaller form-factor detector active area.