Abstract: A disclosed digital sensor includes a pair of piezoelectric sensors that respond to acceleration and pressure in opposite ways, a pair of digital transducer circuits each employing a quantized feedback path to obtain digital sensor signals for the piezoelectric sensors, and a combiner circuit that combines the digital sensor signals to produce a compensated digital output signal. The compensated digital output signal may be a pressure compensated acceleration signal, an acceleration compensated pressure signal, or both. Also disclosed is a signal detection method that includes configuring a pair of piezoelectric membranes in a piezoelectric sensor to respond to acceleration and pressure in opposite ways, and based on their responses, producing at least one of a digital pressure compensated acceleration signal and a digital acceleration compensated pressure signal. The digital signals may be produced in part by applying a quantized feedback signal to at least one of the piezoelectric membranes.

Abstract: A disclosed pressure-responsive sensor includes a flexible element contained within an enclosure and a membrane configured to exert an electrostatic force on the flexible element to cause the flexible element to respond to pressure variations on the membrane. A disclosed pressure-sensing method includes electrostatically coupling a membrane to a flexible element contained within an enclosure to transfer a pressure response of the membrane to the flexible element. Motion of the flexible element is converted into a pressure signal.

Abstract: A disclosed data acquisition system includes one or more streamers having multiple spaced apart sensor units. At least one sensor unit includes at least one digital sensor employing a quantized feedback loop to produce a digital output signal. A data recording system collects and stores data from the sensor units. The quantized feedback loop may be adapted to exert a quantized force on the sensing element. A described method for acquiring data includes deploying at least one streamer having multiple spaced apart sensor units, where at least a portion of the sensor units include a digital sensor employing a quantized feedback loop to produce a digital output signal. A stimulus event is triggered. Data is received from the sensor units and stored.

Abstract: A passive sound pressure level (SPL) limiter is provided that can be used with audio sources of varying drive levels and headsets, earbuds, etc. of varying sensitivity. The SPL limiter includes a control circuit that includes a rectifier and, in most configurations, a step-up transformer. The SPL limiter also includes a limiting circuit that utilizes a transistor to shunt current from the audio source in proportion to a control signal output by the control circuit. The control circuit may further include a low pass filter, for example an RC filter, and one or more fast limit diode paths. The limiting circuit may further include a feedback network to increase the linear behavior of the limiting circuit.

Abstract: A merged particle velocity signal is generated by combining a recorded vertical particle velocity signal, scaled in an upper frequency range using a time-dependent arrival angle as determined by cross-ghosting analysis, with a simulated particle velocity signal, calculated in a lower frequency range from a recorded pressure signal using a time-varying filter based on the time-dependent arrival angle. Combined pressure and vertical particle velocity signals are generated from the recorded pressure and merged particle velocity signals.

Abstract: A passive sound pressure level (SPL) limiter is provided that can be used with audio sources of varying drive levels and headphones or earphones of varying sensitivity. The SPL limiter includes a control circuit and left and right channel limiting circuits, each of which includes a pair of FETS. The SPL limiter may include a balancing circuit that separates the control signal output by the control circuit into left and right channel control signals. The SPL limiter may also include a microphone, for example integrated into an earpiece cable.

Abstract: A time-dependent arrival angle is determined at a single receiver station in a towed streamer. Up-going and down-going pressure wavefields are calculated from pressure and vertical particle velocity wavefields measured at the receiver station. Extrapolated up-going and down-going pressure wavefields are generated from the up-going and down-going pressure wavefields displaced by a time delay based upon the time-dependent arrival angle.

Abstract: A passive sound pressure level (SPL) limiter is provided that can be used with audio sources of varying drive levels and headsets, earbuds, etc. of varying sensitivity. The SPL limiter includes a control circuit that includes a rectifier and, in most configurations, a step-up transformer. The SPL limiter also includes a limiting circuit that utilizes a transistor to shunt current from the audio source in proportion to a control signal output by the control circuit. The control circuit may further include a low pass filter, for example an RC filter, and one or more fast limit diode paths. The limiting circuit may further include a feedback network to increase the linear behavior of the limiting circuit.

Abstract: A high temperature polyamide coating and a fastener coated with a composition that includes from about 60 wt. % to about 80 wt. % of an aliphatic polyamide having a repeating unit. The composition also includes from about 3 wt. % to about 9 wt. % of an epoxy based resin having a molecular weight in the range from about 525 to about 585, from about 4 wt. % to about 10 wt. % of a ceramic microsphere material and from about 2 wt. % to about 5 wt. % of a thermoplastic methacrylate binder, from about 4 wt. % to about 12 wt. % of crushed glass, from about 0.1 wt. % to about 1 wt. % of a polyamide with a secondary amino group as a curing agent, and the balance of an epoxy based curing agent.

Abstract: A time-dependent arrival angle is determined at a single receiver station in a towed streamer. Up-going and down-going pressure wavefields are calculated from pressure and vertical particle velocity wavefields measured at the receiver station. Extrapolated up-going and down-going pressure wavefields are generated from the up-going and down-going pressure wavefields displaced by a time delay based upon the time-dependent arrival angle.

Abstract: A merged particle velocity signal is generated by combining a recorded vertical particle velocity signal, scaled in an upper frequency range using a time-dependent arrival angle as determined by cross-ghosting analysis, with a simulated particle velocity signal, calculated in a lower frequency range from a recorded pressure signal using a time-varying filter based on the time-dependent arrival angle. Combined pressure and vertical particle velocity signals are generated from the recorded pressure and merged particle velocity signals.

Abstract: A merged particle velocity signal is generated by merging a recorded vertical particle velocity signal, scaled in an upper frequency range using a time-dependent arrival angle as determined by velocity analysis, with a simulated particle velocity signal, calculated in a lower frequency range from a recorded pressure signal using a time-varying filter based on the time-dependent arrival time. Combined pressure and vertical particle velocity signals are generated by combining the recorded pressure and merged velocity signals.

Abstract: An enhanced anaerobic adhesive composition containing microencapsulated metal ions is disclosed. Microencapsulated metal ions, such as iron oxide, copper naphthenate, cobalt naphthenate, ferrocene, and ferrocene derivatives, act as bonding sites in the composition, such that the composition achieves more complete polymerization in a shorter curing time. The curing properties and the cure quality are significantly improved by the inclusion of microencapsulated metal ions. The composition can be used to bond metal and plastic substrates.

Abstract: A high temperature polyamide coating and a fastener coated with a composition that includes from about 60 wt. % to about 80 wt. % of an aliphatic polyamide having a repeating unit. The composition also includes from about 3 wt. % to about 9 wt. % of an epoxy based resin having a molecular weight in the range from about 525 to about 585, from about 4 wt. % to about 10 wt. % of a ceramic microsphere material and from about 2 wt. % to about 5 wt. % of a thermoplastic methacrylate binder, from about 4 wt. % to about 12 wt. % of crushed glass, from about 0.1 wt. % to about 1 wt. % of a polyamide with a secondary amino group as a curing agent, and the balance of an epoxy based curing agent.

Abstract: A method of transferring media files over a communications network, typically the Internet. The files are divided by the provider computer into a series of encoded files which are maintained in the provider computer and are transferred over the communications network in a specific sequence to receiving computer. A user loadable program is also maintained in the provided computer and that together with all file types contributing to the content of the communication are also transferred over the communications network to the receiving computer. The received files can then be reproduced by the receiving computer in the correct sequence.

Abstract: A steering wheel assembly has a mounting plate which secures a molded steering wheel to a steering shaft in a vehicle. The mounting plate has a pair of slots having respective longitudinal axes which intersect the plane of the steering wheel at a six o'clock position with an included angle of approximately ninety (90) degrees. The longitudinal axis of one of the slots intersects a transverse axis of the steering wheel at a forty-five (45) degree angle at a three o'clock position and the longitudinal axes of the other slot similarly intersects the transverse axis at the nine o'clock position. The slots are effective to control energy absorption and deflection of the steering wheel when it is impacted at a position other then the twelve o'clock position.

Abstract: A marine seismic surveying method recording with a first sensor a first signal indicative of pressure and with a second sensor a second signal indicative of motion, calculating a coupling mechanism filter for the second signal substantially correcting for the imperfect coupling of the second sensor, and applying a filter based on the coupling mechanism filter to at least one of the signals.