A machine maintenance action can be detected at a location using acoustic analysis of the machine to detect a probable maintenance action. Acoustic data is received at a computer from a plurality of microphones at a location. The acoustic data is analyzed with respect to a database of specifications for the machine, and the analysis of the acoustic data includes correlating the acoustic data to the specifications of the machine stored in the database. A first measured parameter for the machine is determined as outside a first specification of the machine, and indicates a first measurement variation from the first specification of the machine. The first measurement variation is assessed to determine a reason for the first measurement variation in relation to an identified part. An alert is sent to a device with a recommendation or action regarding the identified part, based on the reason for the first measurement variation.

A state estimation apparatus 1 includes an acquisition unit 2 that acquires deterioration information indicating a deterioration state of each structural object and a learning unit 3 that learns common information that is common between pieces of the deterioration information and estimation index information that is used for estimating a deterioration state of a target structural object, using the deterioration information as input.

A method comprises providing a sample holder having a holding space for a sample comprising particle(s) in a fluid medium, the holder comprising a wall providing a wall surface portion, and providing a signal generator for generating an acoustic wave in the holder; providing using the signal generator a driving signal to the holder generating a standing longitudinal acoustic wave in the holder comprising at least one of a node and an antinode; and determining an acoustic resonance frequency characteristic. The method further comprises: providing a sample comprising particle(s) in a fluid medium in contact with the wall surface portion; determining a variation in the resonance frequency characteristic of the holder; determining a difference in position of one or more of the particles with respect to a node and/or an antinode of the acoustic wave and/or the wall surface portion, in particular contact, attachment and/or adhesion.

According to various aspects, a resonator includes a paper base. The paper base includes a channel bounded by least partially infused wax into the paper base. The resonator further includes an electronically conductive segment physically contacting the paper base. The resonator further includes a hydrogel component coating at least a portion of the electronically conductive segment.

According to various aspects, a resonator includes a paper base. The paper base includes a channel bounded by least partially infused wax into the paper base. The resonator further includes an electronically conductive segment physically contacting the paper base. The resonator further includes a hydrogel component coating at least a portion of the electronically conductive segment.

Provided are a method and device for recognizing a speaker by using a resonator. The method of recognizing the speaker includes receiving a plurality of electrical signals corresponding to a speech of the speaker from a plurality of resonators having different resonance bands; obtaining a difference of magnitudes of the plurality of electrical signals; and recognizing the speaker based on the difference of magnitudes of the plurality of electrical signals.

Provided are a method and device for recognizing a speaker by using a resonator. The method of recognizing the speaker includes receiving a plurality of electrical signals corresponding to a speech of the speaker from a plurality of resonators having different resonance bands; obtaining a difference of magnitudes of the plurality of electrical signals; and recognizing the speaker based on the difference of magnitudes of the plurality of electrical signals.

An ultrasonic horn includes a generally cylindrical input section having an energy input end, a generally cylindrical output section having an energy output end, and a throat section disposed between the input section and the output section, the throat section being defined by a side wall having a continuous curve and having a diameter tapering down from a diameter generally equal to a diameter of the input section on a side connected to the input section, and tapering down from a diameter generally equal to a diameter of the output section on a side connected to the output section, to a minimum throat diameter. The minimum throat diameter is smaller than the diameter of the output section and the diameter of the output section is smaller than the diameter of the input section. The side wall of the throat section has a constant radius of curvature.

An ultrasonic horn includes a generally cylindrical input section having an energy input end, a generally cylindrical output section having an energy output end, and a throat section disposed between the input section and the output section, the throat section being defined by a side wall having a continuous curve and having a diameter tapering down from a diameter generally equal to a diameter of the input section on a side connected to the input section, and tapering down from a diameter generally equal to a diameter of the output section on a side connected to the output section, to a minimum throat diameter. The minimum throat diameter is smaller than the diameter of the output section and the diameter of the output section is smaller than the diameter of the input section. The side wall of the throat section has a constant radius of curvature.

An electro-acoustical transducer such as a Piezoelectric Micromachined Ultrasonic Transducers is coupled with an adjustable load circuit having a set of adjustable load parameters including resistance and inductance parameters. Starting from at least one resonance frequency or at least one ring-down parameter of the electro-acoustical transducer a set of model parameters is calculated for a Butterworth-Van Dyke (BVD) model of the electro-acoustical transducer. The BVD model includes an equivalent circuit network having a constant capacitance coupled to a RLC branch and the adjustable load circuit is coupled with the electro-acoustical transducer at an input port of the equivalent circuit network of the model of the electro-acoustical transducer. The adjustable load parameters are adjusted as a function of the set of model parameters calculated for the BVD model of the electro-acoustic transducer to increase the bandwidth or the sensitivity of the electro-acoustic transducer.