A heat/acoustic wave conversion component includes a partition wall that defines a plurality of cells extending from a first end face to a second end face, and has a cell hydraulic diameter HD of 0.4 mm or less, an end face open frontal area of 60% or more and 93% or less, and heat capacity per unit length in the extending direction that tends to decrease with distance from the first end face. A first end portion on the first end face side that accounts for a region of 10% of a total length of the heat/acoustic wave conversion component has 1.1 times or more the heat capacity of that of a second end portion on the second end face side that accounts for a region of 10% of the total length.

Examples of a pressure wave generator configured to generate high energy pressure waves in a medium are disclosed. The pressure wave generator can include a movable piston with a guide through which a piston control rod can move or slide. The pressure wave generator can include a transducer coupled to a medium. During an impact of the piston on the transducer, the control rod can slide in the guide, which can reduce stress on the rod. The pressure wave generator can include a damper to decelerate the control rod, independently of the piston. Impact of the piston on the transducer transfers a portion of the piston's kinetic energy into the medium thereby generating pressure waves in the medium. A piston driving system may be used to provide precise and controlled launching or movement of the piston. Examples of methods of operating the pressure wave generator are disclosed.

An energy collecting device is disclosed. For example, the energy collecting device comprises a plate layer having a plurality of perforations for receiving a plurality of molecules, a molecular energy collecting layer, coupled to the plate layer, having an impacting structure for receiving the plurality of molecules, and a substrate layer, coupled to the molecular energy collecting layer, having a conductor wire coil for collecting electrons that are generated when the plurality of molecules impacts the impacting structure.

A heat/acoustic wave conversion component includes a plurality of monolithic honeycomb segments each including a partition wall that defines a plurality of cells extending between both end faces, and the plurality of monolithic honeycomb segments each mutually converts heat exchanged between the partition wall and the working fluid in the cells and energy of acoustic waves resulting from oscillations of the working fluid. In the heat/acoustic wave conversion component including the plurality of honeycomb segments each being monolithic configured, hydraulic diameter HD of the cells is 0.4 mm or less, open frontal area of the honeycomb segments is 60% or more and 93% or less, heat conductivity of the honeycomb segments is 5 W/mK or less, and a ratio HD/L of the hydraulic diameter HD to the length L of the honeycomb segment is 0.005 or more and less than 0.02.

A heat/acoustic wave conversion unit includes a heat/acoustic wave conversion component and two heat exchangers. Hydraulic diameter HD of the cells in the heat/acoustic wave conversion component is 0.4 mm or less, and a ratio HD/L of HD to the length L of the heat/acoustic wave conversion component is from 0.005 to 0.02. One of the heat exchangers includes a heat-exchanging honeycomb structure and an annular tube that surrounds a circumferential face of the heat-exchanging honeycomb structure. The annular tube includes a structure body that is disposed in the channel to increase a contact area with the heated fluid, an inflow port into which the heated fluid flows, and an outflow port through which the heated fluid flows out. At least one of the heat-exchanging honeycomb structure and the structure body is made of a ceramic material that contains SiC as a main component.

A heat/acoustic wave conversion component includes a partition wall that defines a plurality of cells, inside of the cells being filled with fluid that oscillates to transmit acoustic waves, the heat/acoustic wave conversion component mutually converting heat exchanged between the partition wall and the fluid and energy of acoustic waves resulting from oscillations of the fluid. The plurality of cells have an average of hydraulic diameters HDs that is 0.4 mm or less in a plane perpendicular to the cell extending direction, the heat/acoustic wave conversion component has an open frontal area at each end face of 60% or more and 93% or less, and distribution of hydraulic diameters HDs of the plurality of cells has relative standard deviation that is 2% or more and 30% or less.

A thermal management system for an aircraft is provided that includes thermo-acoustic engines that remove and capture waste heat from the aircraft engines, heat pumps powered by the acoustic waves generated from the waste heat that remove and capture electrical component waste heat from electrical components in the aircraft, and hollow tubes disposed in the aircraft configured to propagate mechanical energy to locations throughout the aircraft and to transfer the electrical component waste heat back to the aircraft engines to reduce overall aircraft mass and improve propulsive efficiency.

A device and method for treating a wound of a patient with negative pressure is provided. The device comprises a heat-assisted pump system. The pump system can be powered in part by heat derived from the patient. The pump system may be configured to be highly planar, light weight, and portable. The pump system may comprise a Stirling engine or a thermal acoustic engine.

A device and method for treating a wound of a patient with negative pressure is provided. The device comprises a heat-assisted pump system. The pump system can be powered in part by heat derived from the patient. The pump system may be configured to be highly planar, light weight, and portable. The pump system may comprise a Stirling engine or a thermal acoustic engine.

A thermoacoustic transducer apparatus is disclosed including at least one thermal converter operable to provide power conversion between acoustic power and thermal power in a pressurized working gas contained within a working volume, a portion of which extends through the thermal converter. The thermoacoustic transducer is operable to cause a periodic flow in the working gas during operation. The apparatus also includes a reservoir volume in fluid communication with the working volume through a conduit having a working volume end in fluid communication with the working volume and a reservoir volume end in fluid communication with the reservoir volume. The conduit has a bore size and length operable to cause pressure oscillations at the working volume end to be converted to flow oscillations at the reservoir volume end such that periodic fluid flow at the reservoir volume end is at least twice as large as periodic fluid flow at the working volume end thereby facilitating a steady fluid flow along the conduit for equalization of working gas static pressures between the working volume and the reservoir volume while providing a sufficiently high acoustic impedance at the working volume end to minimize losses due to periodic flows of working gas within the conduit.