Abstract: In some aspects, an acoustic analysis system includes an acoustic source and a laser vibrometer. In some instances, the acoustic source can generate an acoustic signal in a wellbore defined in a subterranean region, and the laser vibrometer can detect movement of a surface in the wellbore in response to the acoustic signal. The detected movement can be analyzed, for example, to identify properties of materials in the subterranean region.

Abstract: In some embodiments, an apparatus and a system, as well as a method and article, may operate to substantially simultaneously measure acoustic radiation from a source in a geological formation, at each of at least two sensors in an array, over a selected time period to provide acoustic pressure measurements. Further activity may comprise locating the source at a location in the geological formation with respect to the sensors by determining acoustic intensity associated with the source, based on the acoustic pressure measurements, independent of medium sound velocity in one or more media disposed between the sensors and the source. Additional apparatus, systems, and methods are disclosed.

Abstract: In some aspects, an acoustic analysis system includes an acoustic source and a laser vibrometer. In some instances, the acoustic source can generate an acoustic signal in a wellbore defined in a subterranean region, and the laser vibrometer can detect movement of a surface in the wellbore in response to the acoustic signal. The detected movement can be analyzed, for example, to identify properties of materials in the subterranean region.

Abstract: A structural and acoustical vibration dampener for a rotatable blade comprises a layer of structural/acoustic damping material coupled to at least a portion of the blade. A fan blade comprises a structural layer and a layer of damping material coupled to at least a portion of the structural layer. A method of applying a structural and acoustical vibration dampener to a fan blade comprises identifying a region on the fan blade and securing the structural/acoustical vibration dampener to the fan blade over at least a portion of the region.

Abstract: An acoustical vibration dampening system for a rotatable blade comprises at least one section of a rotatable blade and a layer of acoustic damping material coupled to a portion of the at least one section of a rotatable blade. A fan blade comprises a first structural section of a fan blade, a second structural section of the fan blade, and a layer of acoustic damping material provided between the first structural section and the second structural section of the fan blade. A method of making a fan blade with acoustic damping comprises forming at least two sections of a fan blade, and disposing an acoustical vibration dampener between the at least two sections of the fan blade.

Abstract: An acoustical vibration dampening system for a rotatable blade comprises at least one section of a rotatable blade and a layer of acoustic damping material coupled to a portion of the at least one section of a rotatable blade. A fan blade comprises a first structural section of a fan blade, a second structural section of the fan blade, and a layer of acoustic damping material provided between the first structural section and the second structural section of the fan blade. A method of making a fan blade with acoustic damping comprises forming at least two sections of a fan blade, and disposing an acoustical vibration dampener between the at least two sections of the fan blade.

Abstract: A structural and acoustical vibration dampener for a rotatable blade comprises a layer of structural/acoustic damping material coupled to at least a portion of the blade. A fan blade comprises a structural layer and a layer of damping material coupled to at least a portion of the structural layer. A method of applying a structural and acoustical vibration dampener to a fan blade comprises identifying a region on the fan blade and securing the structural/acoustical vibration dampener to the fan blade over at least a portion of the region.