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: Wavefront sensors are provided herein. An aperture mask is configured to receive incident light the wavefront of which is to be measured and comprising irregularly spaced apertures that respectively transmit sub-beams of the incident light. A diffuser is configured to receive the sub-beams transmitted by irregularly spaced apertures of the aperture mask. A camera, having a focal plane in which the diffuser substantially is located, is configured to obtain a digital image of the diffuser and thus to obtain a digital image of the incident light the sub-beams of which the aperture mask transmits onto the diffuser. A controller is configured to electronically receive the digital image of the diffuser and to measure the wavefront of the incident light based on the digital image. Methods also are provided.

Abstract: A system for training a model using federated learning is provided. The system includes a server, and a plurality of vehicles. Each of the vehicles includes a controller programmed to: transmit first knowledge data including information about a plurality of feature vectors and information about a plurality of predictions, receive first aggregated knowledge from the server, and train a local model based on the first aggregated knowledge. The server averages the first knowledge data received from the plurality of vehicles to generate the aggregated knowledge.

Abstract: A method and system of casting. The system of casting including a mold, a water inlet, and an outlet valve. The mold including a mold fluid inlet and a mold fluid outlet. The water inlet being selectively fluidly coupled to the mold fluid inlet via a first valve. The mold fluid outlet being fluidly coupled to the outlet valve.

Abstract: System, methods, and other embodiments described herein relate to estimating reachable states for a vehicle using a neural model. In one embodiment, a method includes generating an unverified command by a first controller and a safety command by a second controller for a projected path by an automated driving system (ADS) associated with a vehicle. The method also includes estimating reachable states by a neural network (NN) model that uses the unverified command and an initial condition for the vehicle, the reachable states representing positions and orientations for the vehicle within a bounded time and a state space associated with the initial condition and the projected path. The method also includes, upon determining that the reachable states satisfy collision criteria, executing by the vehicle a maneuver with the safety command for the projected path and generating subsequent commands using vehicle data from the first controller and the second controller.

Abstract: An electrolyte includes a composite salt mixture with a halogenated boron cluster salt. The halogenated boron cluster salt includes a cation selected from Li+, Na+, Mg2+, Ca2+, Zn2+ and Al3+, and a halogenated boron cluster anion. The halogenated boron cluster anion has a structure of [CB(y?1)H(y?z?i)RzXi]?, [C2B(y?2)H(y?t?j?1)RtXj]?, [C2B(y?3)H(y?t?j)RtXj]?, [C2B(y?3)H(y?t?j?1)RtXj]2?, or [C2B(y?4)H(y?t?j?1)RtXj]2?, [CB(y?1)H(y?z)Rz]?, [C2B(y?2)H(y?t?1)Rt]?, [C2B(y?3)H(y?t)Rt]?, [C2B(y?3)H(y?t?1)Rt]2?, and/or ByH(y?z?i)RzXi]2?, where y is an integer within a range of 6 to 12, (z+i) is an integer within a range of 0 to y, (t+j) is an integer within a range of 0 to (y?1), and X is F, Cl, Br, or I. Also, the composite salt mixture can be at least 90 mol % halogenated, for example, at least 90 mol % mono-halogenated or less than 10 mol % mono-halogenated.

Abstract: An appendage pressurization device includes an appendage strap and one or more artificial muscles disposed in the appendage strap and communicatively coupled to a controller. Each artificial muscle includes a housing comprising an electrode region and an expandable fluid region, a dielectric fluid housed within the housing, and an electrode pair positioned in the electrode region of the housing, the electrode pair comprising a first electrode fixed to a first surface of the housing and a second electrode fixed to a second surface of the housing, wherein the electrode pair is actuatable between a non-actuated state and an actuated state such that actuation from the non-actuated state to the actuated state directs the dielectric fluid into the expandable fluid region, expanding the expandable fluid region.

Abstract: A non-invasive time domain reflection probe calibration method includes: using different volume ratio of ethanol and deionized water mixed solution to calculate a test target's medium weight coefficient and waveguide length of the non-invasive time domain reflection probes; using different concentrations of NaCl solutions to calibrate a waveguide geometric dimensioning of the non-invasive time domain reflection probes; preparing compacted soil samples with known different moisture contents and densities, and calibrating a correlation parameter of compacted soil samples' dielectric constant and conductivity with moisture content and density. The method not only determines the sensitivity of the test target medium of the non-invasive time domain reflection probes, but also obtains the waveguide length and geometric dimensioning of the probe, and realizes an accurate test of moisture content and density of the soil.

Abstract: A system, method and storage medium for synchronization between nodes includes transmitting, by a first node, a first synchronization message; determining, by the first node, a first time at which the first synchronization message is transmitted; transmitting, by the first node, a second synchronization message containing a tx timestamp corresponding to the first time; receiving, by a second node, the first synchronization message from the first node; determining, by the second node, a second time at which the first synchronization message is received; storing, by the second node, a rx timestamp corresponding the second time; receiving, by the second node, the second synchronization message from the first node; determining, by the second node, a current local time at which the second synchronization message is received; reading, by the second node, the tx timestamp in the first synchronization message; adjusting, by the second node, the current local time of the second node by adding a difference between the

Abstract: Seal assemblies, gaskets, bearing assemblies, and their components can be used as pre-packaged seal systems and pre-packaged seal and bearing systems. The seal assemblies can be orientated in different configurations for different applications. Gaskets to restrict flow and gaskets with memory lips to operate as sealing lips can be included to increase the number of sealing points. In a pre-packaged configuration, the cylinder can be a straight cylinder, a stepped cylinder, or a split cylinder. Bearing assemblies can be pre-packaged with the sealing assemblies and service grease may optionally be used to provide lubrication and limit fluid incursion into the spring cavities.

Abstract: A navigation-communication-integrated metamaterial sonar for underwater vehicles is provided, and belongs to the field of ocean detection and communication. The metamaterial sonar is a metamaterial composite structure including a group of disc array with the same diameters, a disc backboard and water gaps. By adjusting the period p of the disc array, a board thickness t1 of each disc, the thickness g of each water gap, the radius w1 of the disc array, the radius w2 and the thickness t2 of the backboard, the working states of underwater navigation and underwater acoustic communication may be flexibly switched by changing working frequencies, and the navigation-communication-integrated sonar may be realized.

Abstract: A flexural wave absorption system detects, with a sensor attached to a beam, an incident wave propagating in the beam. The system determines, based on a signal from the sensor generated in response to the incident wave, an amplitude and phase of the incident wave propagating in the beam and controls an actuator connected to the beam to generate a suppression wave, based on the amplitude and the phase of the incident wave, that reduces a coefficient of reflection of the incident wave across a broadband frequency range.

Abstract: An optoelectronic package structure and a method of manufacturing an optoelectronic package structure are provided. The optoelectronic package structure includes a photonic component. The photonic component has an electrical connection region, a blocking region and a region for accommodating a device. The blocking region is located between the electrical connection region and the region for accommodating a device.

Abstract: Disclosed are a method and system for evaluating sonar self-noise at a ship design stage. The method includes: building a ship structure full-scale geometric simulation model; acquiring loss factors and sonar transducer space outfitting acoustic absorption coefficient material parameters; acquiring mechanical excitation, hydrodynamic excitation, and propeller excitation; inputting the loss factors and the sonar transducer space outfitting acoustic absorption coefficient material parameters into an established statistical energy evaluation model, and applying a mechanical excitation to a face plate of foundation of the built ship structure full-scale geometric simulation model, applying a hydrodynamic excitation to the surface of a ship hull, and applying a propeller excitation to a stern shaft to perform calculation of sonar self-noise of a ship to obtain total spectral density level of the sonar self-noise; and evaluating spectral density level calculation results by index requirements.

Abstract: An aircraft can include a wing. The wing can include a tip. A winglet can be pivotably connected to the wing proximate the tip. A connecting member can be operatively connected to the wing and the winglet. The connecting member can include a flexible material with a super elastic material member operatively connected to the flexible material. Thus, the connecting member can allow passive movement of the winglet responsive to real-time operational forces acting upon the aircraft. In some arrangements, the flexible material can be a fabric, and the super elastic material member can be a wire. In some arrangements, the super elastic material member can be configured to exhibit a non-linear stiffness profile. The non-linear stiffness profile can include a region of quasi-zero stiffness. The stiffness profile of the super elastic material member can be selectively varied, such as by controlling a temperature of the super elastic material member.

Abstract: A semiconductor package includes a substrate having a first side and a second side opposite to the first side, a first type semiconductor die disposed on the first side of the substrate, a first compound attached to the first side and encapsulating the first type semiconductor die, and a second compound attached to the second side, causing a stress with respect to the first type semiconductor die in the first compound. A method for manufacturing the semiconductor package described herein is also disclosed.

Abstract: An underarm gang operated vacuum break switch (underarm switch) has an electrically live portion under a mounting arm, which provides advantages over the standard vacuum break switch, which have the electrically live portion above the mounting arm. Because the non-electrified mounting arm is above the electrified portion, the underarm switch is safer for perching birds and other wildlife. The nature of the underarm switch also provides other benefits including a disconnect blade that when opened creates a visual gap to ensure electrical discontinuity along with a safety locking arm tied to deactivating the underarm switch. Adding to the safety measures is a visual indicator that shows an electrician when the switch is live and safe to open the disconnect blade. Other safety measures include a shock absorber assembly and inertia slowing mass protecting electrical contacts within the vacuum break switch from failing.