Abstract: Apparatus for measuring electrolyute concentrations in fluid samples. The apparatus includes an ion selective electrode having a plurality of ion selective detection sites. Each site has an affinity for a preselected electrolyte of interest and generates a potential having a magnitude related to the concentration of the corresponding electrolyte in the sample. A voltage to optical transducer circuit is provided to convert the voltage differentials to optical signals having intensity related to the concentration of the electrolytes in a first embodiment, a digital code related to the concentration of the electrolytes in a second embodiment, and an optical absorption or density value related to the concentration of the electrolytes in a third embodiment. The optical signals are suitable for detection by conventional optical detector apparatus of assay instruments and may be processed using conventional two point linear interpolation techniques to determine the concentrations of the preselected electrolytes.

Abstract: An apparatus and method are used for determining the cleanliness of an electronic circuit assembly (ECA) such as printed circuit boards (PCB) following noraml cleaning and flux removal processes. The apparatus and method are used to quantitatively measure the ionic and organic contaminants remaining on an ECA. The apparatus utilizes small volumes of isopropanol, a conductivity/resistivity probe and cell and a spectrophotometric analytical instrument. The apparatus generally provides for washing the "cleaned" of defluxed ECA with a measured volume of isopropanol and thereafter measuring the ionic and organic contaminants in the wash solution. The results can then be compared to a standard.

Abstract: The present invention provides a passive superconducting sensor for quench detection in a superconducting coil. The sensor consists of a first circuit electrically connected to two voltage taps of a superconducting coil. The first circuit uses nonsuperconducting components and preferably contains a resistive element. The first circuit is magnetically coupled to a second circuit by a hybrid transformer. The second circuit is superconducting and contains a readout coil and preferably a second hybrid transformer. The second hybrid transformer is magnetically coupled to a sense coil which detects flux changes in the superconducting coil. The readout coil is coupled to a readout device which measures changes in the current through the readout coil. The current in the readout coil can be made a function only of the resistance of the superconducting coil between the voltage turns and thus can be used to detect a quench.

Abstract: A fuel or fluid level measurement arrangement for a spacecraft includes one or more electromagnetic transmission lines extending into the reservoir. The presence of fuel adjacent the transmission line changes the dielectric constant or loss characteristics of the transmission line(s) in a measurable manner. In one embodiment, strip transmission lines extend parallel to the fluid surface at various degrees of ullage, and the fuel level can be established to within the spacing between the transmission lines.

Abstract: A charged-particle distribution measuring apparatus includes a particle passing member having a plurality of through-holes through which portions of a beam of charged particles can pass, a particle trapping member for trapping charged particles that have passed through the through-holes, a recoil particle trapping member disposed between the particle passing member and the particle trapping member, and a mechanism for moving the members to measure the spatial distribution of the charged particle beam. Preferably, the through-holes in the particle passing member are uniformly distributed in a checkerboard pattern. The movement of the members permits measurement of the currents produced by the charged particle beam at various intervals between the locations of the through-holes at the beginning of the measurement. The measurement of the charged particle beam intensity at positions across through the beam, rather than at fixed locations within the beam, improves the resolution of the measured distribution.

Abstract: A method and apparatus for determining the impedance of the discharge in a plasma reactor system comprising a tuning box having variable capacitors is described. The impedance of the discharge is determined in dependence on a pre-established relationship between the operational positions of the variable capacitors on the one hand and the impedance of the discharge on the other. The ionic current relative to the discharge in the reactor also may be determined by taking into account the high frequency voltage of the reactor.

Abstract: A circuit for sensing the state of a potentiometer includes a capacitor that is connected to the potentiometer wiper and that is successively charged by applying a voltage to each end of the potentiometer resistive element. The capacitor is discharged between successive chargings. The times needed to charge the capacitor to a predetermined voltage in each case are used to determine the position of the wiper along the resistive element. The circuit can be connected to a plurality of potentiometers, any one of which can be selected and the wiper position determined. A similar circuit can determine the state of an inductive or capacitive voltage divider.

Abstract: Disclosed is a container holding a partially conductive ionic fluid with a flexible tactile surface covering the fluid and sealing the container. Along the bottom of the container a series of parallel conductors are located with the farthest spaced apart conductors being connected to a voltage source. Measurements of changes in voltages between individual pairs of conductors will provide an indication of any localized deformation of the flexible tactile surface. Such a tactile sensor can be utilized in any device where an electrical output is desired which is indicative of the surface or surface characteristics of the object to be contacted.

Abstract: A method for measuring the surface area of an electrically surface-conductive body comprises applying an a.c. voltage between the body and a corrosion-resistant opposite electrode, both being immersed in an electrically conductive solution having no corrosive influence upon the surface of the body. An electric capacity value for the body is obtained. The measured value is inserted in the function of a surface area and a similar measurement or value obtained using another body having a known surface area in a similar manner. If the body to be treated does not exhibit surface conductivity, the body may be coated on the surface with a conductive material.

Abstract: A particle counter, of the type utilizing a Coulter(R) type aperature and a suction flow path downstream from the aperture, has a pair of electrodes on both sides of the aperture. A current is provided from the downstream electrode to the upstream electrode and pulses in the resulting voltage across the aperture are monitored to detect the passage of blood cells through the aperture. A grounded electrode is placed in the downstream flow path at a position near the package panel to isolate the cell counter from external electrical noise signals. An isolated high input inpedance amplifier is coupled to provide the monitored voltage to an inserted electrode positioned between the downstream aperture electrode and the grounded panel electrode. Because the inserted electrode and downstream electrode are then at the same voltage, no current flows through that portion of the flow path.

Abstract: An apparatus for measuring the electrical charge condition of non-conductive particles in a liquid medium comprising a flow path having sensory means for developing a signal proportional to a desired ion activity and a reciprocating piston carrying a grounded electrode. The reciprocating piston induces liquid to flow past the sensory means and the electrode on the piston screens external galvanic interferences and lower electrode impedance. The electrical signals are monitored by an electronic component.

Abstract: Mobile ion concentrations are measured in thick and disordered oxides by heating to a temperature greater than about 250.degree. C.; using a triangular voltage sweep-like method with applied voltages substantially greater than normally used heretofore; and observing peak displacement currents at voltages, e.g., greater than 60 volts, substantially greater than zero volts.

Abstract: A method for monitoring, over time, changes that occur in the apparent dielectric constant of a selected volumertic space. The selected space may be formed by a substantially homogenous material, in which case, dielectric-constant changes are interpretable, according to the invention, to indicate pressure and/or temperature changes in the space. In another situation, the selected space may be nonhomogenous, in which case dielectric-constant changes are interpretable, also according to the invention, to indicate relative volumetric changes between different media within the space.

Abstract: A metal-insulator-semiconductor (MIS) diode having a suspended electrode forming a cavity between the electrode and the insulator is operated in the charge storage, i.e. inversion, mode to detect a fluid concentration. A reverse bias voltage is applied to the diode to form a charge inversion layer in the semiconductor, the bias is disconnected and subsequently reapplied. The charge that flows upon reapplication of the bias voltage is a measure of the concentration of a fluid in the cavity. An array of MIS diodes with multiplexed biasing and charge measurement permits detection of combinations of different fluids, even in the presence of potentially interfering chemical species.

Abstract: An interface circuit for use in a portable apparatus for measuring the electrochemical characteristics of a sample is disclosed. A disposable cartridge, including a plurality of interconnected flow chambers, houses a printed circuit board substrate upon which reference and indicating electrodes are formed. The electrodes are employed in the presence of chemical reagents to aid in the electrochemical determination of a sample undergoing analysis. Such a system provides a high source impedance signal. Interface circuitry is provided between the electrodes and measuring electronics which causes a controllable current loop to be formed through the physical contacts points between the electrodes and the measuring electronics so that low ohmic contact is established. The control circuitry for the current loop is isolated from the measuring circuitry so that measurements taken are not influenced by the current loop formation.

Abstract: Apparatus and method for studying particles suspended in an electrically conducting fluid by providing an aperture with a current path therethrough, causing the fluid to flow through the aperture and detecting resistive pulses caused by the passage of suspended particles. Additional information about particle size is generated by designing the aperture such that its cross-section changes progressively along its length, and observing the duration of the resistive pulses, which duration varies with particle size. The method is particularly useful for the study of particles suspended in molten metal.

Abstract: An apparatus for detecting contamination on probe surface which comprises a sweep voltage generator for generating sweep voltage which is applied to a probe or probes in plasma, a probe current detection circuit for detecting probe current which flows in accordance with the sweep voltage applied, an amplitude discriminator for comparing the probe current with a predetermined threshold and generating an output signal when the probe current becomes equal to the predetermined threshold, a first sample-hold circuit for sampling and holding the sweep voltage upon reception of the output signal from the amplitude discriminator while the sweep voltage is increasing, a second sample-hold circuit for sampling and holding the sweep voltage upon reception of the output signal from the amplitude discriminator while the sweep voltage is decreasing, and a subtracter for providing a difference between the sweep voltages holded in the first and second sample-hold circuit.

Abstract: A liquid level sensor system well suited for sensing the level of fuel in aircraft fuel tanks includes a plurality of capacitive sensors which provide an output capacitance that is a function of the fraction of the sensor wetted by the fuel. A plurality of sensors are positioned in the liquid-containing tank with each sensor having a first and at least a second probe-specific liquid-quantity profile corresponding to a first and at least a second attitude of the tank. The capacitance of the sensors are determined as function of the length of the respective sensor wetted by the liquid. A memory is provided with a first and second sets of address locations containing liquid-quantity profile information for the sensors for their respective first and second attitudes. The memory is addressed by determining an address offset as a function of the attitude of the system, the relative location of the profile information for the sensor, and the fraction of the sensor wetted by the liquid.

Abstract: A circuit is utilized for measuring a diffusion-limited current which flows through a diffusion-limited current element in proportion to an oxygen concentration which includes an output resistor connected in series with the element, a differential amplifier having a first input connected to a reference voltage supply source, a second input connected to ground, an output connected to the output resistor, and a feedback resistor connected between the first input of the differential amplifier and a point between the element and the output resistor, so that a bias voltage applied across the element is kept constant.

Abstract: Flow measuring apparatus comprising a probe (1) coupled via a coaxial cable (2) to control circuitry with a current to voltage convertor (10), absolute value circuit (12), auto zero switch and integration (11, 27) and voltage to current circuit (18) yielding an analog output, corresponding to flow at the probe.

Abstract: A particle analyzer which comprises a constricted passage for the passage of fine particles contained in a suspension therethrough for isolation, upstream and downstream passages communicated with the constricted passage and positioned on upstream and downstream sides of the constricted passage with respect to the direction of flow of the suspension, a detector including upstream and downstream electrodes disposed in the upstream and downstream passages, respectively, so as to confront with each other for detecting the fine particles being passed through the constricted passage, and a cleansing passage communicated with either one of the upstream and downstream passages for the supply of a cleansing liquid.

Abstract: This invention is an apparatus for measuring fluid density of mixed phase fluid flow. The apparatus employs capacitive sensing of the mixed phased flow combined with means for uniformizing the electric field between the capacitor plates to account for flow line geometry. From measurement of fluid density, the solids feedrate can be ascertained.

Abstract: A method of testing coating integrity of containers includes the steps of introducing a probe into an electrolytic solution into the container and applying a constantly-increasing voltage to the probe from a source and taking readings of the voltage when the current flow through the container reaches a predetermined level. The apparatus also includes a gripping mechanism for producing a positive contact between the metal in the container and the remainder of the circuit.

Abstract: A particle detector in which a pair of pipe elements are coupled together through an aperture and the liquid to be tested is passed through the pipe elements and the aperture with a voltage or current applied to the liquid through the pipe elements acting as electrodes so that the diameter of the pipe elements is reduced because the electrodes are not provided in the pipe elements.

Abstract: Disclosed is a method and apparatus which can detect progress of degradation of a sodium-sulfur cell and predict possibility of final breakdown of the cell in a very near future before such a final breakdown of the cell actually occurs. The method and apparatus for diagnosing the presence or absence of an abnormal state in the sodium-sulfur cell, containing a porous electrical conductive material impregnated with molten sulfur or sodium polysulfide as its positive electrode reactant and containing sodium as its negative electrode reactant, comprises observing the operating voltage of the cell during charging and discharging so as to detect occurrence of a minute ripple in the operating voltage, and, when the amplitude of the ripple and the frequency of occurrence of the ripple increases as a result of repeated cycles of charging and discharging, deciding that degradation of the cell has progressed to an extent that final breakdown of the cell will occur in a very near future.

Abstract: A beam profile scanner includes a probe constructed of a material that will emit electrons when struck by a particle beam such as an ion beam. The probe is passed through the ion beam and the electrons emitted by the probe are detected when they strike a detector surface that is configured and oriented to offer a substantially symmetric view to the moving probe in order to minimize changing capacitance noise. The detector surface is electrically connected to an analyzer circuit that monitors and further processes the current caused by electrons striking the dectector surface and that generates a signal corresponding to the ion beam profile. In the preferred embodiment, the detector surface is a circular metal plate charged to attract electrons emitted by the probe, and the symmetric view of the surface with respect to the probe helps to maintain noise at an acceptably low level.

Abstract: A method of investigating the condition of biological particles, in particular the fraction of viable cells in a bacteria population involves applying a voltage and monitoring the voltage induced by magnetic induction in a detector coil. The applied voltage is of a variable frequency alternating voltage and is preferably induced in the medium through a drive coil.

Abstract: An electrochemical differential resistance measurement arrangement usable for detecting low concentration ionic impurities such as chemical warfare agents in liquids such as water. The disclosure includes details of electrochemical cells used in the liquid resistance measurement arrangement including one cell with fixed electrode positions and a selective ion transmitting membrane one cell with adjustable electrode position, and a combination cell. A differential bridge electrical circuit, together with a preferred form of alternating current energization therefor, an effluent circuit therefor and a balancing method sequence of steps for the bridge, are also included.

Abstract: The invention relates to a type of proximity sensor. In one form, two sinusoidal signals travel along two transmission lines near an object. When the distance between one or both of the lines and the object changes, the speed of travel of one or both of the signals changes. There is a correlation between the speed change and the distance, thus allowing one to infer distance from speed change. One way to measure the speed change is to measure the phase relationship between the two signals.

Abstract: Disclosed is a method for measuring the metal exposure in a resin covering area of a metal container or a constituent member thereof, which comprises contacting the resin covering area of the metal container or the constituent member thereof with a measuring electrode through an electrolytic solution, relatively moving the resin covering area and the measuring electrode in a certain direction while always holding the electrolytic solution between the measuring electrode and the resin covering area, measuring a leak current between the metal substrate of the metal container or constituent member at predetermined pitches and detecting the metal exposure of the resin covering area as leak currents at respective parts discriminately.According to this measuring method, the degree of the metal exposure can be easily measured as the leak current at respective parts discriminately, and statistical processing of the measured leak current values can be easily performed.

Abstract: An apparatus for the measurement of the red blood cell deformability having a measurement cell formed of two electrically insulated compartments clamped mechanically one against the other, with a commercially available multipore membrane therebetween, each of the parts having inlet and outlet orifices as well as a cavity having one electrode and a lateral hole. One of the cavities contains a buffer, the other being intended to receive a suspension of red blood cells consisting of a dilution of a small volume of red blood cells in a large volume of an isotonic conducting buffer, having a volume concentration allowing substantially the transit of a single red blood cell at a time through the multipore membrane, under the action of a device for applying pressure connected to the cavity containing the suspension. An electronic device translates into transit times the electric impedance variations corresponding to the transit of each single red blood cell through the multipore membrane.

Abstract: There is described a method and apparatus for the determination of hematocrit levels in which both the conductivity of whole blood and the conductivity of blood plasma are determined together. While a conductivity cell (18) is being used for the determination of the conductivity of whole blood, the conductivity of plasma is calculated in a computer (30) with the aid of ion selective electrodes (14, 16) from the sodium or potassium concentrations.

Abstract: An apparatus for producing a signal that is representative of the profile of an ion beam and compensates for the system noise of the ion beam profile scanner includes an ion beam profile scanner which produces a beam profile signal that is proportional to the profile of the ion beam and that has system noise from the scanner. A reference signal is produced which has a frequency proportional to the scan frequency of the beam profile signal, and at least one harmonic of the reference signal is also produced. The reference signal and at least one harmonic of the reference signal are individually adjusted in phase and amplitude to match the system noise in the beam profile signal, and the two adjusted signals are subtracted from the beam profile signal in a summation circuit. The resulting signal is representative of the beam profile and has reduced noise as compared to the beam profile signal.

Abstract: A streaming current detector includes an optical shutter rotated by the shaft of the motor which reciprocates a piston between electrodes in a bore containing sample fluid. An electronic synchronous detector is controlled by the output of a light detector whose source is interrupted by the optical shutter. The alternating current signals from the electrodes are connected to an operational amplifier having its inverting input connected to its output solely by a capacitor so that the output voltage is proportional to the charge of the fluid.

Abstract: Offshore or onshore electrical surveys of buried or submerged structures such as pipeline are conducted in a fixed-cell-to-moving-cell fashion either before or after one or more established pipe-to-electrolyte potentials can be obtained. The results of the fixed-cell-to-moving-cell survey are then corrected by a summation of the fixed-to-moving-cell recorded potential and the established potential at the location of the established potential to obtain a reliable electrical survey of the structure. As indicated, the fixed-cell-to-moving-cell survey may be conducted either before or after the established potential is obtained or either before or after a disposable wire survey using a direct connection to the structure.

Abstract: The electrochemical sensor, which is designed more especially for monitoring the correct function of exhaust gas cleaning means in exhaust gas systems, has a solid electrolyte and a diffusion barrier of porous material and is arranged downstream from the exhaust gas cleaning means in the exhaust gas pipe. The sensor operates in a temperature range of -50.degree. C. to 500.degree. C., throughout which it functions substantially independently of temperature. Preferably nitrogen oxides are used as representative components for monitoring the efficacy of the exhaust gas cleaning means and a signal is produced when the signal from the sensor exceeds a given value.

Abstract: A method of investigating the condition of biological particles, in particular the fraction of viable cells in a bacteria population involves applying a voltage and monitoring the voltage induced by magnetic induction in a detector coil. The applied voltage is of a variable frequency alternating voltage and is preferably induced in the medium through a drive coil.

Abstract: The invention relates to the continuous or discontinuous analysis of the corrosive effect of the soil and the environment on a buried metallic structure (such as an underground gasoline storage tank for retail gas stations). The apparatus includes a measuring system having a sensor with at least one Cu/CuSO.sub.4 electrode to which a metallic electrode containing iron is secured at least one voltmeter, and optionally at least one current generator; at least one data display and acquisition system consisting of at least one amplifier, at least one analog-to-digital converter, at least one magnetic recorder and at least one display unit for the read-out of these data on the site, these belonging to the group formed by the numerical display devices and the electromechanical recorders; and a system for the processing of these data consisting of data-processing computing means.

Abstract: Apparatus for use in detecting micro-organisms in any one of a plurality of samples of a liquid, such as a food or drink product, e.g. for control of production, comprises a plurality of containers (11) for the sample and a container-mounting member (10) to receive and locate each of the containers, each container being provided with a first electrode of a noble metal (16) and a second electrode, which may be constituted by the body of the container (11), insulated from the first and of a different metal. The container-mounting member (10) is provided with separate contacts (12) and leads for each of the noble metal electrodes (16) and with contacts (922) connected to a common lead for each of the second electrodes.

Abstract: The deformability measurement chamber is subdivided by a foil into two chamber spaces. The foil has a passage opening, the diameter of which is smaller than the diameter, at rest, of a red blood corpuscle. A static pressure gradient exists between the two chamber spaces, so that a flow takes place from one chamber space to the other. In the region of the passage opening there is situated on each side of the foil an electrode, which is connected to an alternating voltage source. In order to achieve a measurement signal which is approximately one order of magnitude greater, at a given alternating voltage frequency, a current-measuring operational amplifier is disposed in the connecton of one electrode to the voltage source.

Abstract: Gas species are detected with a capacitor having a solid, ionic dielectric excited by an AC voltage in the range from 0.01-30 Hz, with an amplitude of 1-100 millivolts to allow physisorption processes and/or with an AC voltage in the same frequency range and amplitudes from 0.01-3 volts to achieve chemisorption reactions. The AC impedancae of the capacitor is detected for both physisorption and chemisorption excitation to determine gas species and concentration. In chemisorption, diode like action occurs, and is detected by AC harmonic detection processes. The surface of the dielectric on which the gas is incident is overlaid with a grid or porous electrode, fabricated of inert metal or a catalyst which causes the capacitor to enable preferential adsorption by the dielectric of certain materials, to indicate the presence of certain gases. Plural capacitors, having different adsorption characteristics in response to different gases facilitates detection of plural gases.

Abstract: A method of detecting structural abnormalities of a structure composed of an electrically conducting crystalline or non-crystalline substance with no band gap. Piezoelectricity and/or pyroelectricity (electric energy) generated by dynamical energy such as pressure and heat applied to the structure are taken out directly from the structure and measured, thereby accurately detecting the distribution and directivity of the structural abnormality resulting from stresses in the structure.

Abstract: A sensor for measuring partial pressures of oxygen with an ion-conducting lid electrolyte of zirconium dioxide as the sensor element, which is arranged between two electrodes for measuring an electrically measurable quantity, is improved so that it is usable at an operating temperature of about 200.degree. C., by providing that the zirconium dioxide as the solid electrolyte is solely in its tetragonal modification and containing an addition of about 2-3 mol % yttrium oxide.

Abstract: A circuit, which is useful to provide data needed to measure the electrical opacity of a particle, for instance a blood cell, passing through a Coulter type transducer, includes a current source for providing a conventional d.c. current through the sensing aperture of the transducer, as well as an oscillator for providing a high frequency current through the aperture. The oscillator includes an active device and a resonant circuit, and the aperture is coupled in parallel with the resonant circuit of the oscillator. The oscillator can be any type of oscillator, such as a Hartley oscillator. As a particle passes through the aperture, the resistance of the aperture increases, which in turn, increases the Q of the oscillator circuit, whereby the oscillator output signal is amplitude modulated in accordance with the increased Q. This amplitude modulated signal can be detected to provide a value based on the high frequency reactance of the particle being detected. The change in d.c.

Abstract: Disclosed is a method of determining the state of charge and discharge of a host material, e.g., a hydride forming hydrogen storage material, or the interstitial content of an alloy material by the high frequency measurement of the time varying transfer function thereof.

Abstract: Disclosed is a process and apparatus for measuring, in a continuous and contact-free manner, the thickness of a layer applied to a support. The apparatus includes a measuring apparatus which comprises a corona and a first electrostatic voltmeter positioned downstream of the corona in the direction of travel of the layer being measured. The process includes the steps of passing the layer under the apparatus, charging the layer in a contact-free manner, and measuring the level of the charging voltage.

Abstract: A corrosion sensor which is fabricated by photofabrication techniques in the form of two reduced size electrodes, which have wide and narrow areas so that both the instantaneous corrosion rate and the time averaged corrosion rate can be measured.

Abstract: A debris detector for a particle counter, such as a blood cell counter, of the COULTER (R) type. When a particle, or transient debris, passes through the sensing orifice of the particle detector, a voltage pulse occurs; whereas, when debris lodges in or against the orifice of the particle detector, a d.c. voltage shift occurs. The voltage at the orifice is capacitively coupled to an amplifier and the output of the amplifier is integrated. The capacitor coupling the orifice voltage to the amplifier causes an undershoot voltage at the trailing edge of each particle or transient debris pulse, such that a zero average voltage is applied to and, hence, from the amplifier for each voltage pulse. The integrated voltage is applied to a voltage comparator to provide an output signal therefrom whenever the integrated voltage exceeds a reference voltage. The comparator output signal is provided to a delay circuit having a delay related to the time required for a particle to pass through the COULTER detector orifice.

Abstract: Disclosed is a method and apparatus for measuring the percentages of oil and water present in an oil/water mixture. By measuring the energy absorption properties of the oil/water mixture, the percentages of oil and water present in the oil/water mixture can be determined regardless of whether the oil or the water is in the continuous phase and regardless of what the relative proportions of water and oil are. Measuring the energy absorption properties of the oil/water mixture yields a current output which can be plotted on one of two distinct, empirically or theoretically derived, data curves. One of the data curves represents oil being in the continuous phase and the other data curve represents water being in the continuous phase. A comparator is used to determine whether the oil or the water is in the continuous phase to thereby select the proper data curve on which the energy absorption is plotted. Each of the curves has the energy absorption properties of the media plotted against the percentage of water.

Abstract: A general purpose potentiostatic test system, used to provide potentiostatic control of test electrodes using a multiplexer in both the anodic and cathodic regimes. A built-in data switching and measurement subsystem enables rapid and precise determination of the set potentials as well as the test electrode currents. All the test electrodes can be placed in the same test tank and use a single auxiliary electrode.