According to an embodiment, a structure evaluation system includes a plurality of AE sensors, a signal processor, a position locator, and an evaluator. The AE sensors detect an elastic wave generated from a structure. The signal processor performs signal processing on the elastic wave detected by the AE sensors and outputs an AE signal including information on the elastic wave. The position locator derives a source distribution indicating the distribution of sources of the elastic wave generated in the structure, using an AE signal caused by an impact on the structure. The evaluator evaluates a state of deterioration of a predetermined region of the structure from a density of the sources of the elastic wave obtained on the basis of the source distribution.

Examples of determining tuberculation in a fluid distribution system are disclosed. In one example implementation according to aspects of the present disclosure, an acoustical wave generator generates an acoustical wave within a fluid path of a fluid distribution system. A first acoustical sensor and a second acoustical sensor sense the acoustical wave. An acoustical signal analysis module determines an amount of tuberculation within the fluid distribution system by analyzing the sensed acoustical wave.

The invention relates to a method for determining the degree of wear of at least one component of a machining device (10), wherein at least one actual condition (19) of the machining device (10) is established and the at least one actual condition (19) is compared to at least one comparative condition (18) of the machining device (10), and a conclusion is drawn as to the degree of wear of the at least one component as a function of a deviation determined between the at least one actual condition (19) and the at least one comparative condition (18), wherein, to establish the at least one actual condition (19) and/or the at least one comparative condition (18), sound emissions (16) of the machining device (10) are captured. The invention also relates to a device (13) for determining a degree of wear of at least one component of a machining device (10), a machining device (10) for machining workpieces (11), and a computer program for determining a degree of wear of at least one component of a machining device (10).

A system for detecting structural damage to a rigid structure, the system comprising: at least one impact generator capable of applying a one-time impact on the structure; an acoustic sensor; a vibration sensor; and a processing circuitry configured to: provide an indication of the structural damage to the rigid structure upon (a) a first deviation above a first threshold between an expected acoustic wave profile, expected to radiate from the structure, absent the structural damage, and an actual acoustic wave profile being measured by the acoustic sensor in response to an application of the one-time impact, or (b) a second deviation above a second threshold between an expected to vibration profile of expected vibrations of the structure, absent the structural damage, and an actual vibration profile in response to the application.

When frequencies used in the two-frequency measurement of a SAW sensor are represented by f.sub.1 and f.sub.2 (f.sub.2>f.sub.1), an electrical signal processing device is provided without use of oversampling at a frequency higher than twice the frequency f.sub.2 or a two-system low-frequency conversion circuit, in which temperature compensation with the same accuracy as the case where these are used can be realized. Narrow band frequency filtering is applied to a waveform after roundtrips in a delay line type SAW sensor capable of transmitting and receiving multiple frequencies, the two frequencies f.sub.1 and f.sub.2 (f.sub.2>f.sub.1) are extracted, and a delay time is determined utilizing an aliasing obtained by applying undersampling at a frequency lower than twice the frequency f.sub.1.

A pottery shard analyzer may determine one or more characteristics of an unidentified pottery shard. A vibration injector may cause the unidentified pottery shard to vibrate with a vibration signature that is dependent on the one or more characteristics of the unidentified pottery shard. A vibration detector may detect and extract a vibration signature from the vibration of the unidentified pottery shard caused by the vibration injector. A vibration signature comparator may: compare the detected vibration signature of the unidentified pottery shard with vibration signatures of multiple identified pottery shards having one or more known characteristics; and flag one or more of the identified pottery shards that have vibration signatures that are similar to the vibration signature of the unidentified pottery shard.

There is described a method for checking a value document of a specified type for the suspected presence of a forgery, in particular of a pieced-together forgery, wherein at least one ultrasonic property of the value document is captured in a spatially resolved manner so as to form location-dependent measuring data, wherein while employing the location-dependent measuring data it is checked whether there are present in a specified checking region of the value document two areal regions whose ultrasonic properties deviate from each other according to a specified difference criterion, and wherein there is formed an authenticity signal which represents the result of the check. Further, a corresponding checking device is described.

A “periodic signal parameter” (PSP) indicates periodic patterns in an autocorrelated vibration waveform and potential faults in a monitored machine. The PSP is calculated based on statistical measures derived from an autocorrelation waveform and characteristics of an associated vibration waveform. The PSP provides an indication of periodicity and a generalization of potential fault, whereas characteristics of the associated waveform indicate severity. A “periodic information plot” (PIP) is derived from a vibration signal processed using two analysis techniques to produce two X-Y graphs of the signal data that share a common X-axis. The PIP is created by correlating the Y-values on the two graphs based on the corresponding X-value. The amplitudes of Y-values in the PIP is derived from the two source graphs by multiplication, taking a ratio, averaging, or keeping the maximum value.

An analyzer determining/classifying aircraft air contaminants using a contaminant collector comprises a microporous medium, a bypass; a sensor generating frequency response when contaminant mass is added to/removed from the sensor, receiving contaminants desorbed from the medium; a first sample flow path, passing through the collector; a second sample flow path, bypassing the collector; a frequency measurement device, measuring response generated by the sensor as contaminant is added to and removed; a computer readable medium bearing a contaminant recognition program and calibration data; and, a processor executing the program, the program including a module classifying the contaminant and measuring response signal magnitudes, and a module using the data for comparison with magnitude of the response generated by the sensor to calculate contaminant concentration and determine a target value for contaminant type, and using measured response magnitudes to adjust first sample flow rates and/or flow durations based upon measured response magnitudes.

A machine learning device which learns fault prediction of one of a main shaft of a machine tool and a motor driving the main shaft, including a state observation unit observing a state variable including at least one of data output from a motor controller controlling the motor, data output from a detector detecting a state of the motor, and data output from a measuring device measuring a state of the one of the main shaft and the motor; a determination data obtaining unit obtaining determination data upon determining one of whether a fault has occurred in the one of the main shaft and the motor and a degree of fault; and a learning unit learning the fault prediction of the one of the main shaft and the motor in accordance with a data set generated based on a combination of the state variable and the determination data.