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The Basic Nexense Technology
The Nexense Technology provides a technique for measuring virtually any condition influencing the transit of an energy wave (acoustical or electromagnetic) through a medium (solid, gas or liquid). It measures the transit time of such wave with extremely high precisions (fractions of a nanosecond), and thereby permits a very precise measurement of any condition (e.g. temperature, pressure, force, displacement, etc.) which influences the energy wave transit velocity, transit distance, or both.
The basic technique involves transmitting a cyclically repeating energy wave through a transmission channel defined by a transmitter and a receiver at spaced locations in the medium itself while the medium is subject to the condition being detected or measured, and automatically changing the frequency of transmission of the energy wave such as to produce a whole integer number of waves within the transmission channel irrespective of variations in the condition being measured. By utilizing the changes in frequency to provide a measurement of the condition, the technique enables the measurements to be made with an extremely high signal–to–noise ratio, without analog–to–digital conversion, and in a noncontact, nonintrusive and non-emissive manner, thereby making the technique particularly suitable for a wide variety of medical and non‑medical applications.
Following are examples of a number of applications of the basic Nexense Technology which are at different stages of development .
Medical Applications
Biosensor Mattress Pad: A biosensor to be placed under or over a mattress for measuring various cardiac, respiratory and/or other body movements in a non–intrusive manner. Special applications of such a biosensor mattress pad include: a sleep–care devices to detect snoring and to produce a biofeedback stimulus to interrupt the snoring; a partner‑care device for couples; a hospital‑care device for hospital patients; and a geriatric‑care device for geriatric patients.
Vital Signs Monitor: In these devices, the acoustical channel is an elastomeric material in contact with a portion of the person’s body in order to measure respiration and/or cardiac activity of the person. The elastomeric material of the transmission channel is compressed during respiratory and cardiac movements such that precise measurements of the changes in length of the transmission channel produce precise measurements of the respiration and/or cardiac activity sensed. The device may be applied to the person in the form of a waistband, wristband, etc.
Heart–Motion Trigger for MRI: In this application, the biosensor directly senses heart–motion and synchronizes the operation of an MRI or other imaging system to thereby produce sharper images. The sensor is preferably an acceleration–type sensor placed in direct contact with the person’s body to measures the rate‑of‑change or acceleration in the contacted portion of the body and to produce the signals for triggering MRI or other imaging system.
Finger–Tip Probe: This is an application of the vital‑signs monitor, wherein the sensor is incorporated in a key of a cellular phone for measuring a person’s pulse, or in a keyboard for permitting finger–pressure operation of a water–proofed keyboard.
Non‑Invasive Glucose Monitor: This application of the Nexense Technology utilizes photoacoustical waves for non‑invasively detecting and measuring glucose levels in a person. The monitor may be carried on a band applied to the person’s wrist, or in a clip applied to a person’s earlobe.
Ear–Probe: This product is in the form of an ear plug to be received in the person’s ear for measuring the temperature and/or pressure of the blood in the carotid artery.
Non–Medical Applications
Reaction–Chamber Monitor: This application of the Nexense Technology permits measurements of temperature, pressure, and/or composition to be made in a reaction chamber (such as one for processing semi–conductor chips) in a real–time manner, with high accuracy, without the need for frequent recalibration, and without interfering with the processing operations, disturbing the temperature distribution, and/or hindering the handling of the workpieces. The monitoring device introduced into the reaction chamber includes three acoustical channels all based on the Nexense Technology: one channel serves as a reference for measuring temperature; the second includes a deformable membrane to provide a measurement of the chamber pressure; and the third channel is exposed to the gas within the chamber to provide a measurement of the actual composition within the chamber.
Panel Condition Sensor: This application enables various types of panels to be monitored for various conditions in a non‑destructive manner. For example, it enables stresses or cracks to be detected in an aircraft panel, the presence of water, pressure or cracks to be detected in a windshield panel; or movement to be detected in a floor panel.
Torque Sensor: This application provides a highly sensitive technique for detecting and measuring the torque applied to a shaft, e.g. for measuring the output torque of a vehicle engine for controlling the fuel feed to increase fuel mileage and decrease air pollution, to indicate the wear condition of the engine, etc. Such a torque sensor includes two acoustical channels, in which the applied torque is effective to decrease the length of one channel while increasing the length of the other channel, such as to produce a torque measurement of high precision and of low sensitivity to temperature or angular velocity.
Bolt Sensor: In this case, the Nexense Technology is implemented in a bolt, for sensing forces applied to structures fastened together by the bolt. A particular promising application of such a sensor is for measuring the weight of a load on a vehicle seat in order to control the actuation of an airbag, or for detecting respiration and/or cardiac activity of the load in order to distinguish living loads (persons) from non–living loads (packages).
Touch–Screen Sensor: This application utilizes a plurality of transmission channels formed in a touch screen to indicate a touch point on the screen, and the location of such touch point by triangulation.
Vibration Sensor: This application provides a vibration sensor of extremely high sensitivity particularly useful for sensing earth vibrations (e.g. in detecting movements of persons or objects in an area protected against intrusion), for oil or gas exploration, for earthquake detection, etc.
Bending–Wave Sensor: This application utilizes bending waves in a wire or like medium for measuring changes in tension on the wire, which produce changes in the transit velocity of the wave through the wire to a much greater extent, in the order of ten times greater, than the elongation (transit distance) changes produced by the tension. The sensed tensile force may be translated into other conditions, for example displacements of a diaphragm for measuring pressure.
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