Abstract: Disclosed are systems that utilize metamaterials to improve the acoustic performance of a panel, such as a glass panel used in automotive applications. In one example, the system may include a panel having an exterior edge and a metamaterial attached adjacent to the exterior edge of the panel. The metamaterial is configured to minimize the reflection coefficient of flexural waves acting upon the panel.

Abstract: Systems, methods, and other embodiments described herein relate to a cooling system that includes vibrating protrusions to disturb a dissipation-blocking thermal boundary layer. In one embodiment, a cooling system includes a base from which vibrating protrusions extend. The base exhibits 1) vibration at multiple frequencies in a first direction and 2) vibration at multiple frequencies in a second direction. The cooling system includes a first set of vibrating protrusions that vibrate in the first direction. Different vibrating protrusions in the first set have different resonance frequencies that align with the multiple frequencies in the first direction.

Abstract: Systems, apparatuses, and methods provide for measuring elastic modulus usable with a tubular object. A sound signal is propagated within the tubular object via a speaker coupled to a proximal end of an impedance tube. The propagated sound signal is measured within the tubular object via a pair of microphones coupled to the impedance tube. An elastic modulus of the tubular object is determined in response to the measurement of the propagated sound signal.

Abstract: A system for identifying autonomous vehicles includes at least one sensor that may be configured to provide sensor data associated with at least two vehicles. A pre-processing module may be coupled to the at least one sensor and may be configured to determine a set of data including at least car following data based on the sensor data. An autonomous vehicle (AV)/human-driven vehicle (HV) identification neural network may be coupled to the pre-processing module and configured to generate an AV/HV identifier for at least one of the at least two vehicles based on at least the car following data during a predetermined time period.

Abstract: A method and a device for direction of arrival estimation based on one-bit quantization antenna array, the method including: designing a received signal model of robust one-bit radar, designing an optimal objective function of the robust one-bit radar, replacing a first function in the optimal objective function with a second objective function to obtain a new optimal objective function, and according to the new optimal objective function, adopting a proximal alternating minimization method and a gradient descent method to solve the optimization problem and obtain an incident angle of a target echo signal. The embodiments reshape the received signal model of the one-bit radar, enabling the received signals to preserve or reflect the distribution information of noise data. The embodiments utilize a specific norm to describe the distribution of noise, effectively suppressing quantization error bits generated by low signal-to-noise ratio when estimating DoA with one-bit algorithm.

Abstract: System, methods, and other embodiments described herein relate to tuning a mechanical resonator for detecting a significant value using an electrical resonator that enhances sensitivity. In one embodiment, a system includes a mechanical resonator having a beam coupled to a body. The system also includes an electrical resonator coupled through a patch to the mechanical resonator, the electrical resonator operating as a shunt and having an inductor and a resistor (LR) circuit in series. The system also includes the electrical resonator that detects, associated with a perturbation of the body, an exceptional point (EP) of the mechanical resonator by varying the LR circuit according to a model.

Abstract: Systems for determining the direction of a surface acoustic wave are described herein. In one example, a system for determining the direction of the surface acoustic wave includes a resonator having a top surface and a sensor configured to output a signal representative of displacements of the top surface at different locations when a surface acoustic wave travels along a support surface that supports the resonator. This signal can then be utilized to determine the direction of the surface acoustic wave.

Abstract: System, methods, and other embodiments described herein relate to absorbing flexural waves. In one embodiment, a system includes a longitudinally extending body that is subject to a flexural wave and a bandpass filter. The bandpass filter transmits a target flexural wave having a particular wavelength and blocks a non-target flexural wave. The bandpass filter includes at least two mechanical resonators coupled to a surface of the longitudinally extending body and aligned in a first linear array along a length dimension of the longitudinally extending body. The at least two mechanical resonators of the first linear array are separated by a distance based on the particular wavelength.

Abstract: An amplitude-adjustable electric spray gun structure, comprising a gun body, motor, paint container, trigger, nozzle assembly, and paint needle. The gun body contains three channels and is equipped with an amplitude adjustment assembly. The nozzle assembly includes both a main and secondary atomization channel. The first channel connects to the motor's air outlet and the main atomization channel. The amplitude adjustment assembly controls the connection and gap between the first and third channels, enabling the airflow to the secondary atomization channel to be adjusted for optimal spray control.

Abstract: A gun body for an electric spray gun with an amplitude adjustment structure positioned on top, comprising a gun body, a material container, a nozzle assembly, and a material needle. The gun body includes a first channel, a second channel, a third channel, and a coating channel, with an amplitude adjustment assembly installed on the gun body. The nozzle assembly has a primary atomization channel and a secondary atomization channel. The primary atomization channel, and the interior of the material container, while the third channel is connected to the coating channel. The amplitude adjustment assembly controls the communication between the first and second channels and adjusts the gap size between them. The gun body not only allows switching between circular and elliptical spray patterns but also controls the gap size between the first and third channels during the rotation of the amplitude adjustment knob.

Abstract: Provided are a direction of arrival (DOA) estimation method and system for a sparse array based on Vandermonde decomposition reconstruction, relating to the technical field of array signal processing. The method includes: constructing a covariance matrix completion optimization model based on sparse array signals and uniform linear array signals, and performing Vandermonde decomposition by using characteristics of a uniform linear array; introducing a nuclear norm to optimize a rank function in the model, and updating the covariance matrix completion optimization model; and introducing an auxiliary variable to transform the model into a solvable optimization problem, and solving the problem by an alternating direction multiplier method to obtain an optimal estimation value. The DOA is estimated using a root multiple signal classification algorithm.

Abstract: A switching device for a pneumatic spray gun, comprising a gun body, a switch rod movably installed back and forth within a switch channel of the gun body, a material adjustment nut screwed onto the rear end of the switch channel, and a material needle inserted into a central hole of the switch rod. The rear end of the switch rod is provided with a rear sealing ring, and the front end of the switch rod is provided with a front sealing ring and a switch sleeve. The switch sleeve presses the front sealing ring tightly. A valve spring is arranged between the material adjustment nut and the switch rod, with the front end of the valve spring abutting against the switch rod, and the rear end connected to the material adjustment nut via a flat washer and an O-shaped sealing ring.

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: System, methods, and other embodiments described herein relate to a high-Q resonant state embedded system in a continuous body. In one embodiment, a system includes a longitudinally extending body that is subject to a flexural wave. The longitudinally extending body is attached to a fixed structure at a first end. The system also includes a mechanical resonator coupled to a surface of the longitudinally extending body along a length dimension of the longitudinally extending body. The mechanical resonator is located at a distance away from a second end of the longitudinally extending body to exhibit an infinite Q factor based on physical properties of the mechanical resonator.

Abstract: Vibration energy harvesting systems are described herein. In one example, a system includes a first structure having a coil, a second structure having a magnet, and a coupling structure connecting the first structure to the second structure.

Abstract: Systems for determining the direction of acoustic waves are described herein. In one example, a system for determining the direction of an acoustic wave includes first and second resonator chambers fluidly connected via a channel. The first and second resonator chambers have a speaker configured to output sound based on signals produced from external transducers when detecting the acoustic wave that is acoustically separated from the first and second resonator chambers. The direction of the acoustic wave can be determined based on a comparison of the first acoustic amplitude sensed in the first resonator chamber and the second acoustic amplitude sensed in the second resonator chamber when the speakers output sound.

Abstract: Systems, methods, and other embodiments described herein relate to estimating direction of a surface acoustic wave (SAW) using temperature measurements from multiple resonators. In one embodiment, a method includes measuring temperatures of multiple resonators that are excited by a SAW using a sensor. The method also includes searching an angle from a temperature ratio of the multiple resonators using the temperatures. The method also includes estimating a direction of the SAW using the angle.

Abstract: Systems and other embodiments described herein relate to an acoustic resonator sensing or mitigating vibration waves associated with a structure having limited bonding. In one embodiment, the acoustic resonator includes a body having an interior channel from an open end to a closed end. The acoustic resonator can also include the body receiving an excitation by a vibration wave that propagates from a structure through the interior channel, the excitation occurring at a resonant frequency. The acoustic resonator can also include the body being proximate to the structure without physical bonding.

Abstract: Described herein are alterable optical structures. Also described herein are methods of altering same.

Abstract: The present disclosure is directed to embodiments of a tower structure with at least partially additively manufactured, stacked tower sections. Embodiments of the tower structure have a plurality of stacked tower sections, wherein at least one tower section of the plurality of stacked tower sections includes a wall element having one or more printed layers, and a base holding thereon the one or more printed layers. The present disclosure also is directed to a method of manufacturing a tower structure using a stacked tower sections and additive manufacturing. Embodiments of the method include forming a base of poured concrete or cast material, printing and depositing one or more printed layers to form a wall element, and stacking the plurality of tower sections to form the tower structure.