Abstract: A stable towable submersible device includes a rigid body that is towed at a positive pitch angle relative to the device's direction of motion. An acoustic projector housing extends vertically from the rigid body. When the rigid body rolls about its roll axis, which is tilted at the positive pitch angle, the acoustic projector rolls about the roll axis changing the acoustic projector's angle of attack relative to the direction of motion and generates a restoring force causing the acoustic projector to rotate back to a generally vertical orientation.

Abstract: An underwater acoustic source can include a first piston coupled to a second piston and a plurality of linear magnetic actuators directly connected to each of the first piston and the second piston. Each of the plurality of linear magnetic actuators include a linear shaft positioned within the cylindrical magnetic assembly and mounted to the first end of the rigid ferromagnetic housing and the second end of the rigid ferromagnetic housing, such that the linear shaft is stationary, and linear bearings positioned between the cylindrical magnet assembly and the linear shaft to allow the cylindrical magnet assembly to translate along the linear shaft relative to the cylindrical electrical coil, and wherein each of the plurality of linear magnetic actuators is activated, the first piston and the second piston oscillate towards and away from each other, causing acoustic waves to be generated in water.

Abstract: A stable towable submersible device includes a rigid body that is towed at a positive pitch angle relative to the device's direction of motion. An acoustic projector housing extends vertically from the rigid body. When the rigid body rolls about its roll axis, which is tilted at the positive pitch angle, the acoustic projector rolls about the roll axis changing the acoustic projector's angle of attack relative to the direction of motion and generates a restoring force causing the acoustic projector to rotate back to a generally vertical orientation.

Abstract: A tow body arrangement for a towable device in a sonar system includes a bridle having a front for connecting to a first tow cable and back for connecting to a second tow cable. The tow body arrangement also includes a tow body rotatably connected to the bridle between the front and back of the bridle. The tow body is shaped to generate hydrodynamic forces tending to rotate the tow body perpendicular to a longitudinal axis of the bridle.

Abstract: An underwater acoustic source can include a first piston coupled to a second piston and a plurality of linear magnetic actuators directly connected to each of the first piston and the second piston. Each of the plurality of linear magnetic actuators include a linear shaft positioned within the cylindrical magnetic assembly and mounted to the first end of the rigid ferromagnetic housing and the second end of the rigid ferromagnetic housing, such that the linear shaft is stationary, and linear bearings positioned between the cylindrical magnet assembly and the linear shaft to allow the cylindrical magnet assembly to translate along the linear shaft relative to the cylindrical electrical coil, and wherein each of the plurality of linear magnetic actuators is activated, the first piston and the second piston oscillate towards and away from each other, causing acoustic waves to be generated in water.

Abstract: An apparatus includes a marine seismic source having a volume of gas and a gas reservoir, and the marine seismic source and the gas reservoir are coupled to permit a resonating gas flow to pass therebetween. The apparatus may be a component of a marine seismic survey system. The apparatus may be utilized in a method of marine seismic surveying.

Abstract: An apparatus is disclosed which may include a plurality of marine seismic sources. According to some embodiments, these marine seismic sources may include a plurality of piezoelectric components. Such an apparatus may provide a useful sound pressure level for conducting marine seismic surveying. According to some embodiments, a conduit may be coupled between the plurality of marine seismic sources and a gas reservoir external to the plurality of marine seismic sources. The conduit may in some embodiments have at least one adjustable dimension for changing a frequency of the apparatus. The apparatus may be used in a method of marine seismic surveying.

Abstract: A system may include a conduit coupled between a marine seismic source and a gas reservoir external to the seismic source. The conduit may have at least one adjustable dimension for changing a resonance frequency of the system. The system may be utilized in a method of marine seismic surveying.

Abstract: A tow body arrangement for a towable device in a sonar system includes a bridle having a front for connecting to a first tow cable and back for connecting to a second tow cable. The tow body arrangement also includes a tow body rotatably connected to the bridle between the front and back of the bridle. The tow body is shaped to generate hydrodynamic forces tending to rotate the tow body perpendicular to a longitudinal axis of the bridle.

Abstract: This document discusses, among other things, a self-test (ST) ground fault circuit interrupter (GFCI) monitor configured to generate a simulated ground fault starting in a first half-cycle of a first cycle of AC power and extending into a second half-cycle of the first cycle of AC power, wherein the first half-cycle of the first cycle of AC power precedes the second half-cycle of the first cycle of AC power. Further, the ST GFCI monitor can detect a response to the simulated ground fault.

Abstract: An apparatus includes a marine seismic source having a volume of gas and a gas reservoir, and the marine seismic source and the gas reservoir are coupled to permit a resonating gas flow to pass therebetween. The apparatus may be a component of a marine seismic survey system. The apparatus may be utilized in a method of marine seismic surveying.

Abstract: An apparatus is disclosed which may include a plurality of marine seismic sources. According to some embodiments, these marine seismic sources may include a plurality of piezoelectric components. Such an apparatus may provide a useful sound pressure level for conducting marine seismic surveying. According to some embodiments, a conduit may be coupled between the plurality of marine seismic sources and a gas reservoir external to the plurality of marine seismic sources. The conduit may in some embodiments have at least one adjustable dimension for changing a frequency of the apparatus. The apparatus may be used in a method of marine seismic surveying.

Abstract: A system may include a conduit coupled between a marine seismic source and a gas reservoir external to the seismic source. The conduit may have at least one adjustable dimension for changing a resonance frequency of the system. The system may be utilized in a method of marine seismic surveying.

Abstract: This document discusses, among other things, a self-test (ST) ground fault circuit interrupter (GFCI) monitor configured to generate a simulated ground fault starting in a first half-cycle of a first cycle of AC power and extending into a second half-cycle of the first cycle of AC power, wherein the first half-cycle of the first cycle of AC power precedes the second half-cycle of the first cycle of AC power. Further, the ST GFCI monitor can detect a response to the simulated ground fault.

Abstract: This document discusses, among other things, a self-test (ST) ground fault circuit interrupter (GFCI) monitor configured to generate a simulated ground fault starting in a first half-cycle of a first cycle of AC power and extending into a second half-cycle of the first cycle of AC power, wherein the first half-cycle of the first cycle of AC power precedes the second half-cycle of the first cycle of AC power. Further, the ST GFCI monitor can detect a response to the simulated ground fault.

Abstract: This document discloses, among other things, apparatus and methods for dimmer control. In an apparatus example, a circuit can include an input configured to receive a control signal, a controller configured to modulate a pulse width of a pulse train using the control signal when the controller is enabled, an output configured to provide the pulse train to a driver, and first and second current limit detectors configured to receive load current information of the driver and to terminate an active pulse of the controller when a value of the load current information exceeds a threshold.

Abstract: This document discusses, among other things, a self-test (ST) ground fault circuit interrupter (GFCI) monitor configured to generate a simulated ground fault starting in a first half-cycle of a first cycle of AC power and extending into a second half-cycle of the first cycle of AC power, wherein the first half-cycle of the first cycle of AC power precedes the second half-cycle of the first cycle of AC power. Further, the ST GFCI monitor can detect a response to the simulated ground fault.

Abstract: This document discusses, among other things, a self-test (ST) ground fault circuit interrupter (GFCI) monitor configured to generate a simulated ground fault starting in a first half-cycle of a first cycle of AC power and extending into a second half-cycle of the first cycle of AC power, wherein the first half-cycle of the first cycle of AC power precedes the second half-cycle of the first cycle of AC power. Further, the ST GFCI monitor can detect a response to the simulated ground fault.

Abstract: This document discusses, among other things, a self-test (ST) ground fault circuit interrupter (GFCI) monitor configured to generate a simulated ground fault starting in a first half-cycle of a first cycle of AC power and extending into a second half-cycle of the first cycle of AC power, wherein the first half-cycle of the first cycle of AC power precedes the second half-cycle of the first cycle of AC power. Further, the ST GFCI monitor can detect a response to the simulated ground fault.