Abstract: A method for determining crook potential of wood is described. One embodiment comprises nondestructively obtaining lengthwise shrinkage rates (from a third party or by direct measurement) of wood and then determining crook potential of the wood based on the lengthwise shrinkage rates. Where the wood comprises lumber, lengthwise shrinkage rate measurements typically are made on at least one major planar surface of the lumber. The method typically comprises determining lengthwise shrinkage rates two or more measuring points separated by a predetermined distance, such as at substantially one-foot intervals along the lumber. Particular embodiments of the present invention determine lengthwise shrinkage rates using infrared radiation, microwave radiation, electricity, ultrasound energy, and combinations thereof Working embodiments of the method use ultrasound energy to determine lengthwise shrinkage rates.

Abstract: A method for determining twist potential of wood is described. One embodiment of the method comprises nondestructively obtaining a grain angle of wood, such as trees or lumber, and then determining twist potential of the wood based on the grain angle. Where the wood comprises lumber, grain angle determinations typically are made on at least one major surface of the lumber. The method typically comprises determining grain angle at at least two measuring locations separated by a predetermined distance, such as at substantially one-foot intervals along the board. The method also can further comprise obtaining at least one fiber dive angle. Particular embodiments of the present invention determine grain angle using infrared radiation, microwave radiation, light energy (such as by using a laser), electricity, ultrasound energy, and combinations thereof. Working embodiments of the method used light energy and ultrasound energy to determine grain angle.

Abstract: The method and structure of a moisture measuring device that creates an electric field and then determines a moisture content of a specimen based on the effect the moisture of the specimen has on the electric field.

Abstract: Device for emission-reception of a stream of electromagnetic waves, in which an emission unit (1) and a reception unit (2) are each supplied with light energy passing through an optical guide (13). This light may be stopped by an optical gate (19). Otherwise, it reaches a micro-laser (4) that illuminates a photo-conducting sheet (5) on which an antenna (3) is located. The portions (6, 7) of the emitter antenna (3) at different potentials are then short circuited and a stream of electromagnetic waves is emitted. The wave stream passes through a medium to be studied and is returned to the receiving unit (2) in which it is sampled, recorded and analyzed to determine the composition of the medium through which it had passed. The wave stream has a wide frequency band and the opto-electronic device can be used to make a very compact system.

Abstract: Microwaves are respectively propagated through a reference fluid and fluid to be measured, both contained in a detection pipe body, and as a result, a first phase lag &thgr;1 and a second phase lag &thgr;2 can be determined on the basis of the microwaves by a phase lag measuring circuit. Then, a density computing circuit subtracts the first phase lag &thgr;1 from the second phase lag &thgr;2 to determine a phase difference &Dgr;&thgr;. When computing the density of matter in the fluid on the basis of the phase difference &Dgr;&thgr;, the density computing circuit performs density computing processing such that a real second phase lag &thgr;2 satisfies the following equation &thgr;2=&thgr;2′+N×360° where N is the number of rotations, and &thgr;2′ is an apparent phase lag obtained by the phase lag measuring circuit.

Abstract: An electromagnetic field generator is provided which consists of a regulated self contained voltage supply connected to a high frequency clock which drives one or more printed circuit board antennas. The clock may be a TTL or ECL based clock for example. The electromagnetic field generator is used in a method of testing the shielding effectiveness of an enclosure. Two measurements are made with a measurement antenna of emissions from the electromagnetic field generator, one with the enclosure in place and another without the enclosure in place, the shielding effectiveness being the difference between these two measurements.

Abstract: An article identification device 4 is mounted on a trap of which operation is diagnosed. The identification device 4 includes a memory 47 in which trap identification data is stored. When the identification device 4 receives an electromagnetic wave from a trap operation diagnosing device, a rectifier 46 derives DC power from the electromagnetic wave, which DC power drives the memory 47 and a modulator 48 so that an electromagnetic wave containing the trap identification data can be sent to the operation diagnosing device. The operation diagnosing device derives the trap identification data from the received electromagnetic wave to identify the trap whose operation the operation diagnosing device diagnoses.

Abstract: A system for transmission measurement with the aid of microwaves for the continuous determination of the concentration of a substance, the system being composed of: a transmission waveguide antenna for radiating microwave energy; a receiving waveguide a for receiving radiated microwave energy, each of the waveguides being provided with a window that is transparent to microwave radiation; and a signal processing circuit connected to the waveguides for supplying a microwave signal to the transmission waveguide antenna to cause the transmission waveguide antenna to radiate microwave energy via the window of the transmission waveguide antenna and for receiving from the receiving waveguide antenna a microwave signal created in the receiving waveguide antenna by microwave radiation received by the receiving waveguide antenna through the window in the receiving waveguide antenna.

Abstract: A measuring technique and method are provided to simultaneously determine the molecular density of several molecular species and the temperature within a closed process room in a melting or combustion process. In such processes in the industry, e.g. in metallurgic process industry, it is important to determine the temperature and the contents within the gas or flame without physically connect to or disturb the process. This has shown to raise large problems especially at high temperatures. The radio signal over a frequency band is measured on the outside of the process room through a window in the mantel covering as a function of frequency and registered on a computer as a radio spectrum. The system is calibrated by using a known signal transmitted through the process room. The spectral lines are identified by their frequency from a database. The temperature is determined from several lines of the same molecular specie and the molecular densities are determined from the intensities of the lines.

Abstract: The present invention finds the overall concentration of a mixture in the following way. It measures the measurement sensitivity of substance C, of which the constituent composition varies, out of multiple substances A, B and C using sensitivity measuring microwave type concentration meter 17. It then inputs this measurement result to calibration curve gradient setter 20. It then finds the calibration curve gradient using a computing device which possesses the relationship of the measurement sensitivity of the single substance of which the constituent composition varies to the calibration curve gradient that finds the overall concentration of substances A, B and C. It then sets this calibration curve gradient in mixture concentration measuring microwave type concentration meter 18.

Abstract: A system for point-level detection of material within a vessel includes a transmission line probe adapted to be mounted to a wall of the vessel so as to extend within the vessel for contact with material when the material reaches a preselected level within the vessel. Electronics are operatively coupled to one end of the probe for launching microwave energy along the probe. The electronics are responsive to a change in microwave energy reflected from the free end of the probe within the vessel when the material is in contact with the probe, employing time-domain reflectometry techniques, for indicating that the material is in contact with the probe. This change in reflected microwave energy may comprise a change in phase or, more preferably, a change in apparent length of the probe resulting from contact with material having a higher dielectric constant than that of air when air surrounds the probe.

Abstract: A method of determining the moisture content of a module of tobacco material, the method comprising the steps of: (a) transmitting a plurality of microwaves substantially through a portion of the module, such that the microwaves are transmitted microwaves; (b) receiving the transmitted microwaves such that the microwaves are received microwaves; (c) determining a phase shift and an attenuation from the received microwaves; (d) repeating steps (a) to (c) for at least a portion of the material on the module, such that a plurality of phase shifts and a plurality of attenuations is obtained; (e) using at least one empirical factor selected from the group consisting of weight of the module, temperature of the module, shape of the module and type of the material to correct the plurality of attenuations, producing a plurality of corrected attenuations; (f) calculating a raw moisture content of the material from the corrected attenuations; (g) determining a density of the material from the phase shifts; and (h) calcu

Abstract: A measuring technique and method are provided to simultaneously determine the molecular density of several molecular species and the temperature within a closed process room in a melting or combustion process. In such processes in the industry, e.g. in metallurgic process industry, it is important to determine the temperature and the contents within the gas or flame without physically connect to or disturb the process. This has shown to raise large problems especially at high temperatures. The radio signal over a frequency band is measured on the outside of the process room through a window in the mantel covering as a function of frequency and registered on a computer as a radio spectrum. The system is calibrated by using a known signal transmitted through the process room. The spectral lines are identified by their frequency from a database. The temperature is determined from several lines of the same molecular specie and the molecular densities are determined from the intensities of the lines.

Abstract: In a process for determining the solids content of a gas flow, in particular for regulating the firing of a boiler with coal dust in a coal-fired power plant, electromagnetic waves are sent from a transmitter (20) to a receiver (21) through the solids-laden gas flow. The attenuation of these electromagnetic waves due to the absorption of part of them by the solids is then determined.

Abstract: Material resistivity measuring apparatus includes a transmitter for transmitting a measurement frequency current through the material to a receiver spaced from the transmitter. The transmitter includes a power amplifier wherein the measurement frequency current is amplified in discrete steps depending upon resistivity of the material. The current level of the transmitter is transmitted to the receiver by modulating the measurement frequency current by a modulation signal whose phase is indicative of power level. The measurement frequency current can be modulated by a second modulating signal which provides a reference phase for the first modulating signal.

Abstract: Electromagnetic waves are driven in the pipe to be inspected in the piping system by a transmitting antenna of a transmitter, to be propagated in the pipe; while a receiving antenna of a receiver is moved outside the pipe along the pipe, to receive leaking electromagnetic waves for inspecting elements of the piping system, and the location concerned of each element of the piping system to be inspected is detected in reference to the location of the receiving antenna where the level of electromagnetic waves received by the receiver becomes a peak. The locations to be inspected are the damaged portions such as holes formed by corrosion, cracks, etc. in the pipes, and the locations of joints, etc. It is also possible to move the transmitting antenna outside along the pipe, while arranging the receiving antenna at proper place in the pipe. Furthermore, it is also possible to move both the transmitting antenna and the receiving antenna in synchronization to effect the above inspection.

Abstract: Electromagnetic waves are driven in the pipe to be inspected in the piping system by a transmitting antenna of a transmitter, to be propagated in the pipe; while a receiving antenna of a receiver is moved outside the pipe along the pipe, to receive leaking electromagnetic waves for inspecting elements of the piping system, and the location concerned of each element of the piping system to be inspected is detected in reference to the location of the receiving antenna where the level of electromagnetic waves received by the receiver becomes a peak. The locations to be inspected are the damaged portions such as holes formed by corrosion, cracks, etc. in the pipes, and the locations of joints, etc. It is also possible to move the transmitting antenna outside along the pipe, while arranging the receiving antenna at proper place in the pipe. Furthermore, it is also possible to move both the transmitting antenna and the receiving antenna in synchronization to effect the above inspection.

Abstract: Electromagnetic waves are driven in the pipe to be inspected in the piping system by a transmitting antenna of a transmitter, to be propagated in the pipe; while a receiving antenna of a receiver is moved outside the pipe along the pipe, to receive leaking electromagnetic waves for inspecting elements of the piping system, and the location concerned of each element of the piping system to be inspected is detected in reference to the location of the receiving antenna where the level of electromagnetic waves received by the receiver becomes a peak. The locations to be inspected are the damaged portions such as holes formed by corrosion, cracks, etc. in the pipes, and the locations of joints, etc. It is also possible to move the transmitting antenna outside along the pipe, while arranging the receiving antenna at proper place in the pipe. Furthermore, it is also possible to move both the transmitting antenna and the receiving antenna in synchronization to effect the above inspection.

Abstract: Method and device for indicating movements of gas bubbles in a liquid, droplets of liquid in a gas or a level of liquid, the liquid or the gas forming a medium in a conduit (15) or a container. Microwave signals of a predetermined frequency are transmitted through a section (G) of the conduit (15) or the container (16) that is pervious to microwaves toward said medium, and microwave signals reflected from the medium are received. Received microwave signals are then utilized to indicate presence of gas bubbles, droplets, or a level of a liquid moving in said conduit (15) or said container (16).Said conduit (15) is designed with a section (G) that is pervious to microwaves, and a microwave transmitter (S) is provided to transmit microwave signals towards said section (G). A microwave receiver (M) is provided to receive microwave signals that are reflected from the medium, and said microwave receiver (M) is operatively connected to a detector (6).

Abstract: A phase difference measuring apparatus obtains a first receive signal by transmitting and receiving a to-be-measured material in a reference state and a second receive signal by transmitting and receiving a signal wave to and from that material in a measured state. The apparatus finds a reference phase difference .theta..sub.1 from the transmit wave and first receive signal and an apparent phase difference .theta..sub.2 ' from the transmit wave and second receive signal. The apparatus adds the apparent phase difference .theta..sub.2 ' to a product of the number of rotations, n, the apparent phase difference .theta..sub.2 ' passes through a given reference point and an angle of 360.degree. to find a true phase difference .theta..sub.2. The apparatus varies the number of rotations, n, to n+1 when the apparent phase difference .theta..sub.2 ', while being increased, passes through the reference point and that number of rotations, n, to n=n-1 when the apparent phase difference .theta..sub.

Abstract: Electromagnetic waves are driven in the pipe to be inspected in the piping system by a transmitting antenna of a transmitter, to be propagated in the pipe; while a receiving antenna of a receiver is moved outside the pipe along the pipe, to receive leaking electromagnetic waves for inspecting elements of the piping system, and the location concerned of each element of the piping system to be inspected is detected in reference to the location of the receiving antenna where the level of electromagnetic waves received by the receiver becomes a peak. The locations to be inspected are the damaged portions such as holes formed by corrosion, cracks, etc. in the pipes, and the locations of joints, etc. It is also possible to move the transmitting antenna outside along the pipe, while arranging the receiving antenna at proper place in the pipe. Furthermore, it is also possible to move both the transmitting antenna and the receiving antenna in synchronization to effect the above inspection.

Abstract: Systems, methods, and probe devices for electronic monitoring and characterization using single-ended coupling of a load-pulled oscillator to a system under test.

Abstract: A monitor for monitoring the moisture content of grain comprises at least one programmable PIN diode attenuator connected between a microwave measurement signal source and a transmit antenna. A controller stores an addressable attenuation table, each location in the table storing an attenuation value and an associated attenuator address. A counter accesses the table locations sequentially and the attenuator addresses are applied to the attenuator to cause a step-wise decreasing attenuation of the measurement signal which is then transmitted through the grain. After the signal passes through the grain, it is detected and applied to a threshold comparator. When the magnitude of the detected signal reaches the threshold, the counter is stopped and the attenuation value at the location pointed to by the counter is taken as the attenuation of the measurement due to moisture in the grain. Once the attenuation has been determined, the moisture content and mass grain flow may be calculated.

Abstract: A water adding control apparatus includes a microwave detecting unit which enables the detection of microwave value proportional to the water content amount of the water added grain and which makes it unnecessary to make calculations for an estimated water content value of the water added grains. The water adding process is started by inputting initial water adding amount, the microwave value of the raw grain after the addition of water is measured, the measured microwave value is set as the target microwave value which serves as control reference, and the water adding amount is feed-back controlled for the actually measured microwave value to constantly match the target microwave value.

Abstract: An apparatus comprising a measuring unit for measuring a property of microwaves by transmitting microwaves through a fluid containing matter to be measured, a storing unit for storing a correction parameter set of a sensitivity coefficient and a mixture ratio concerning the matter to be measured, and a calculating unit for calculating a concentration of the matter to be measured from the property of the microwaves obtained by the measuring unit and the correction parameter set obtained in the storing unit.

Abstract: According to a method and an apparatus for determining absolute plasma parameters in unsymmetrical radio frequency (RF) low-pressure plasmas, a radio frequency discharge current generated in a plasma reactor is measured in the form of analog signals at a portion of the reactor acting as earth electrode, the analog signals are converted into digital signals, and the desired plasma parameters are evaluated from the digital signals by means of a mathematical algorithm. The apparatus includes a meter electrode which is insulatedly positioned in a flange or recess of the reactor wall which acts at least as part of the earth electrode. The method and apparatus may be used with respect to plasma etching in the technical field of the semiconductor technology.

Abstract: A system for detecting accretion of frazil ice on underwater gratings comses a pair of parallel electrically conductive bars mounted side-by-side, for disposition beneath a water surface and spaced from but proximate an underwater intake grating. The system further includes a coaxial transmission line connected at a first end to the pair of bars for extension from the bars upwardly above the water surface, and a time domain reflectometer disposed above the water surface for generating electromagnetic pulses and having a second end of the transmission line fixed thereto. The transmission line facilitates propagation of the pulses to the bars for further travel to distal ends of the bars, and back to the reflectometer. The reflectometer is adapted to compute pulse round trip travel time in the bars and to compute changes in the round trip travel time, from which can be determined absence, presence, and build-up of frazil ice on the bars, providing an indication of same on the grating.

Abstract: The invention provides apparatus and methods for determining electric field properties of an inhomogeneous target. The electric property distribution on a coarse mesh discretization of the target is first estimated; and then the electric field on a fine mesh discretization of the target is computed. The fine mesh has finer discretization than the coarse mesh and is overlapping with the coarse mesh. The electric field is then measured at preselected measurement sites within a homogeneous region external to the target. A Jacobian matrix is also calculated which represents a sensitivity calculation relative to a change in the electric field at selected measurement sites due to a perturbation in the electric property distribution on the coarse mesh. A difference vector is formed between the computed electric field and the measured electric field, and an update vector is added to the electrical property distribution as a function of the difference vector and the Jacobian matrix.

Abstract: A system and method for continuously monitoring the shielding effectiveness f an electromagnetically shielded enclosure is disclosed including an RF transmitter positioned remote from the shielded enclosure. RF signals emitted from the remotely positioned transmitter are received by both an enclosure receiver positioned inside of the enclosure and simultaneously by a reference receiver having its antenna positioned outside of the shielded enclosure. These two received signals are mixed so as to produce IF signals which are subsequently forwarded to a synchronous detector which determines the ratio of the two signal levels by comparing their strengths. This ratio is indicative of the enclosure's electromagnetic shielding effectiveness. If the effectiveness drops below a predetermined or threshold limit, such is determined by a comparator positioned within the enclosure and an alarm may be sounded so as to indicate that the shield is failing.

Abstract: A device and method for determining the proportion of the phases of a multiphase fluid is disclosed. The device includes microwave emission and reception devices which are suited to the composition variation of the multiphase fluid, a processor and control for determining directly, from measurements of amplitude and phase shift of a beam crossing the multiphase medium and a rate of occupation of liquid phase and/or a gas phase for a given section of the pipe. The flow rate of each of the phases is determined.

Abstract: A microwave microscope comprising a microwave waveguide having a probe end positioned closely above the surface to be probed such that the surface is in the near field of the microwave radiation. The end of the probe facing the surface is covered with a metallic foil or a conducting film deposited over a dielectric layer and having a rectangular slit formed therein. The long dimension of the slit is nearly resonant with the microwave, that is, just slightly longer than one-half the microwave wavelength. The short dimension is substantially shorter than long dimension and is chosen such that the slitted end is transparent to the microwave. Thereby, substantial microwave power is emitted through the slit with fine resolution that is determined by the short dimension of the slit. The probe is scanned across the surface in the direction of the short slit dimension, and its resolution is approximately equal to the short slit dimension.

Abstract: A portable microwave measurement instrument is disclosed for measuring an unknown property of a test material, such as moisture content, by generating and transmitting two microwave beams of different frequency through such material so a portion of the beam energy is absorbed by the moisture. The corresponding attenuated received signals are compared in order to compensate for the presence of a component in the test material, which is not being measured but which also absorbs microwave beam energy. A temperature compensation circuit using two thermistors is connected to the PIN diode attenuators to adjust their attenuation characteristics in compensation for changes in temperature. To determine the density of the test material, one of the microwave signals is used to measure the phase shift of the corresponding received signal and produce a phase shift output signal.

Abstract: A phase difference measuring apparatus obtains a first receive signal by transmitting and receiving a to-be-measured material in a reference state and a second receive signal by transmitting and receiving a signal wave to and from that material in a measured state. The apparatus finds a reference phase difference .theta..sub.1 from the transmit wave and first receive signal and an apparent phase difference .theta..sub.2 ' from the transmit wave and second receive signal. The apparatus adds the apparent phase difference .theta..sub.2 ' to a product of the number of rotations, n, the apparent phase difference .theta..sub.2 ' passes through a given reference point and an angle of 360.degree. to find a true phase difference .theta..sub.2. The apparatus varies the number of rotations, n, to n+1 when the apparent phase difference .theta..sub.2 ', while being increased, passes through the reference point and that number of rotations, n, to n=n-1 when the apparent phase difference .theta..sub.

Abstract: A lubricating/hydraulic fluid condition monitor in which a coaxial microwave resonator is placed in a fluid conduit to determine changes in the chemical properties and debris concentration is disclosed. Microwave radiation is applied to the resonator for measuring the resonant frequency and resonator Q. An externally powered electric or magnetic field is used to alternately align and misalign debris in the fluid while the resonator properties are being measured. A logic unit automatically generates tables of resonant frequency and Q versus resonator mode and external field strength. This set of tables constitutes a fingerprint of the fluid condition. By matching the fingerprint against a set of fingerprints taken under known conditions, the condition of the fluid is determined.

Abstract: Method and apparatus are provided for determining the velocity of individual food particles within a liquid/solid food mixture that is cooked by an aseptic cooking method whereby the food mixture is heated as it flows through a flowline. At least one upstream and at least one downstream microwave transducer are provided to determine the minimum possible travel time of the fastest food particle through the flowline. In one embodiment, the upstream detector is not required. In another embodiment, a plurality of small dipole antenna markers are secured to a plurality of food particles to provide a plurality of signals as the markers pass the upstream and downstream transducers. The dipole antenna markers may also include a non-linear element to reradiate a harmonic frequency of a transmitter frequency.

Abstract: A method is disclosed for dynamically testing a radio system having output terminals connectable to a speaker system in a motor vehicle wherein the method utilizes a dynamometer, a transverse electromagnetic cell, a signal generator and a signal analyzer and includes the steps of placing the motor vehicle in the transverse electromagnetic cell, connecting the output terminals to the signal analyzer, operating the motor vehicle on the dynamometer inside the transverse electromagnetic cell, generating a signal using the signal generator, transmitting the signal from the signal generator to the transverse electromagnetic cell, emitting the signal onto the motor vehicle, and measuring an output signal generated by the radio system at the output terminals using the signal analyzer.

Abstract: A method and apparatus for accurately characterizing the electron density and distribution of a confined plasma on the basis of high-frequency, broadband electromagnetic measurements is disclosed herein. The technique involves noninvasive, broadband measurement of electromagnetic transmission through a plasma. In one implementation, multivariate analysis techniques are employed to correlate features of the resultant spectra with plasma characteristics such as electron density or electron distribution. Alternately, such techniques are used to correlate the resultant spectra with parameters relating to conditions under which the plasma is generated. More specifically, the quantitative plasma characterization technique involves generating a set of broadband calibration spectra by measuring transmission of electromagnetic energy through a calibration plasma. Each broadband calibration spectrum is obtained using a different set of reference parameters being related to predefined quantitative characteristics.

Abstract: A two-port, coaxial, waveguide flowline sensor for transmitting TEM mode electromagnetic radio frequency signals through borehole fluids flowing through a longitudinal flowline cavity of the waveguide. The waveguide flowline sensor responds to changes in the conductivity, dielectric constant, and state of the fluid at high borehole temperatures and pressures. The sensitivity of the sensor is enhanced by impedance mismatches between two feedthrough waveguides comprising the ports of the sensor, and a flowline cavity waveguide.

Abstract: A method for determining a stopped flow condition in a fluid fraction measuring apparatus includes the steps of establishing a minimum threshold level of statistical variation in the measured parameter repetitively (continuously) monitored by the measuring apparatus, and giving an indication when the standard deviation, statistical average, or the kurtosis of the measured parameter or characteristic drops to the threshold level.

Abstract: Systems and methods for monitoring workpiece and workpiece material characteristics using microwave energy are disclosed. A system includes a chamber, including means for generating variable frequency microwave energy; means for positioning a workpiece within the chamber; means for subjecting the workpiece to a plurality of different microwave frequencies; and means for monitoring characteristics of the workpiece. One or more characteristics of a workpiece, or workpiece material, may be monitored by positioning the workpiece within a chamber having means for generating variable frequency microwave energy; subjecting the workpiece to microwave irradiation at a plurality of frequencies; detecting power reflection for each one of the plurality of microwave frequencies to provide power reflection data; and comparing the power reflection data to a predetermined set of power reflection data.

Abstract: A system for measuring the moisture content of a multi-layer bale of material, comprising a source of microwave radiation disposed on a first side of the bale for directing a circularly polarized source beam through the bale in a direction substantially parallel to the layers thereof so as to exit from the bale as an exit beam and a conveyor for conveying the bale past the source of microwave radiation. A pair of microwave antennas are disposed on an opposite side of the bale for receiving mutually orthogonal components of the exit beam permitting determination of a maximum amplitude of the exit beam corresponding to an amplitude of the exit beam in a direction normal to the layers of the bale. This permits calculation of an attenuation of the beam consequent to absorption by moisture in the bale and thus allows the moisture content of the bale to be determined.

Abstract: A method and apparatus for detecting grain direction in wood by means of microwave radiation. A sample of timber is exposed to a polarized microwave beam emitted by a transmitter (11). A polarized receiver (12) evaluates the microwave energy that has been affected by the timber. The receiver and transmitter polarization planes are locked at either 0 or 90 degrees respect to each other. Both are rotated synchronously and the received energy is plotted versus angle. The energy maximum or minimum gives indication of the grain direction in the timber sample under evaluation.

Abstract: A phase difference measuring apparatus obtains a first receive signal by transmitting and receiving a to-be-measured material in a reference state and a second receive signal by transmitting and receiving a signal wave to and from that material in a measured state. The apparatus finds a reference phase difference .theta..sub.1 from the transmit wave and first receive signal and an apparent phase difference .theta..sub.2' from the transmit wave and second receive signal. The apparatus adds the apparent phase difference .theta..sub.2' to a product of the number of rotations, n, the apparent phase difference .theta..sub.2' passes through a given reference point and an angle of 360.degree. to find a true phase difference .theta..sub.2. The apparatus varies the number of rotations, n, to n+1 when the apparent phase difference .theta..sub.2', while being increased, passes through the reference point and that number of rotations, n, to n=n-1 when the apparent phase difference .theta..sub.

Abstract: A microwave densitometer comprises a phase difference detecting section for detecting a phase difference between a microwave generated from a microwave generator and a microwave received by a microwave receiver, a rotation number updating section for varying a value of number of rotations "n", a correcting section for obtaining a difference value .DELTA..THETA. indicating a difference between a true phase difference .THETA..sub.2 and a reference phase difference .THETA..sub.1 ' a signal converter for converting the difference value .DELTA..THETA. to a concentration signal an operation mode setter for setting a operation mode, and a holding circuit for holding the number of rotations "n" and the apparent phase difference .THETA..sub.2 ' when a concentration measuring operation of the fluid to be measured is switched to a non-measuring operation in response to a change of the operation mode set to the operation mode setter.

Abstract: A distance measuring system for measuring a distance between two objects has a transmitter assembly mounted on one of the two objects, for transmitting a plurality of electromagnetic waves having respective wavelengths different from each other at respective levels toward the other of the two objects, a receiver assembly mounted on the other object, for receiving the electromagnetic waves transmitted from the transmitting means, and a distance detector for detecting a ratio of levels at which at least one set of electromagnetic waves of the electromagnetic waves is received by the receiving means, as corresponding to a distance between the two objects, and determining the distance between the two objects from the ratio.

Abstract: A narrow field electromagnetic sensor system and method of sensing a characteristic of an object provide the capability to realize a characteristic of an object such as density, thickness, or presence, for any desired coordinate position on the object. One application is imaging. The sensor can also be used as an obstruction detector or an electronic trip wire with a narrow field without the disadvantages of impaired performance when exposed to dirt, snow, rain, or sunlight. The sensor employs a transmitter for transmitting a sequence of electromagnetic signals in response to a transmit timing signal, a receiver for sampling only the initial direct RF path of the electromagnetic signal while excluding all other electromagnetic signals in response to a receive timing signal, and a signal processor for processing the sampled direct RF path electromagnetic signal and providing an indication of the characteristic of an object.

Abstract: A device and method for testing for Cystic Fibrosis includes a sample cell having a capillary tube with a lumen that will hold approximately five microliters of sweat. The capillary tube has metallic rings around each end of the tube with an RF oscillator attached to one ring and a microprocessor attached to the other. An RF signal, which is transmitted from the RF oscillator through the sweat in the sample cell, is subsequently analyzed at the microprocessor by comparing the transmitted signal to a reference. In accordance with the comparison made by the microprocessor, the presence of Cystic Fibrosis may be detected.

Abstract: A method and apparatus are disclosed for testing unpopulated and inactive populated printed circuit boards for manufacturing defects. The method and apparatus do not require electrical contact with the board under test. The method and apparatus include an AC source, which is connected to the stimulator(s). The stimulator(s) radiate an electromagnetic field onto the traces and components on the board under test and this interaction establishes a potential gradient along the traces and components. A sensor array is located adjacent to a stimulator (if only one is used) or between a pair of stimulators (if a dual arrangement is used) and detects the displacement currents flowing from the board under test. The sensors and stimulator(s) do not electrically connect to the board under test, which is positioned between a ground reference plane and a sensor/stimulator unit. By scanning across the entire surface of the board under test, a displacement current signature of the board under test is obtained.

Abstract: An apparatus for measuring an electromagnetic wave stress of an article includes an electromagnetic wave irradiation unit comprising a plurality of radiation probes being adjacent to each other along a surface of the article at least on one side thereof so as to permit the probes to irradiate independently electromagnetic waves on divided local areas on a surface of the article corresponding to the locations of the probes. The apparatus also includes a control unit electrically connected to the article for receiving output signals having information as to existences of any abnormalities in individual divided local areas in the article exposed to an electromagnetic wave irradiation, the control unit being electrically connected to the transmitted unit for controlling operations of the transmitter unit to control independently an excitation of each radiation probe.

Abstract: A method for analyzing a gaseous mixture by means of microwave absorption including the steps of: generating microwave energy of at least one frequency known to be absorbed by the component of interest of the gaseous mixture for the presence of one specific gas component; transmitting two beams of the microwave energy simultaneously to a measuring cell and to a reference cell, both cells containing none of the specific gas component of interest; recombining the microwave energy through the matching arms of a waveguide "magic" tee with an "H" arm and an "E" arm; adjusting the phase and amplitude of the reference or measuring beam signals of microwave energy until a null is detected at the "E" arm of the waveguide "magic" tee and all microwave energy is detected at the "H" arm of the microwave tee; allowing the measuring cell to fill with the gaseous mixture to be analyzed; correlating the energy detected at the "H" arm to the concentration of the gaseous component of interest, according to Beer's law.