Abstract: Contrast agents incorporating super-paramagnetic iron-oxide (SPIO) nanoparticles have shown promise as a means to visualize labeled cells using MRI. Labeled cells cause significant signal dephasing due to the magnetic field inhomogeneity induced in water molecules near the cell. With the resulting signal void as the means for detection, the particles are behaving as a negative contrast agent, which can suffer from partial-volume effects. Disclosed is a new method for imaging labeled cells with positive contrast. Spectrally-selective RF pulses are used to excite and refocus the off-resonance water surrounding the labeled cells so that only the fluid and tissue immediately adjacent to the labeled cells are visible in the image. Phantom, in vitro, and in vivo experiments show the feasibility of the new method. A significant linear correlation (r=0.87, p<0.005) between the estimated number of cells and the signal has been observed.

Abstract: A process and device for detecting electrically conductive particles in a liquid flowing in a pipe section, the liquid being exposed to periodic alternating electromagnetic fields by a transmitter coil which induces eddy currents in the particles, a probe made as a coil arrangement and which has an effective width producing a periodic electrical signal based on the eddy currents. The signal ha a carrier oscillation with an amplitude and/or phase which is modulated by particles passing across the effective width of the coil arrangement, the probe signal being filtered by a frequency-selective first filter unit, the filtered signal being sampled by a triggerable A/D converter stage to obtain a demodulated digital measurement signal, the digital measurement signal being filtered by a digital, frequency-selective adjustable second filter unit to obtain a useful signal, and the useful signal being evaluated to detect passage of electrically conductive particles in the pipe section.

Abstract: A biological detector includes a conduit for receiving a fluid containing one or more magnetic nanoparticle-labeled, biological objects to be detected and one or more permanent magnets or electromagnet for establishing a low magnetic field in which the conduit is disposed. A microcoil is disposed proximate the conduit for energization at a frequency that permits detection by NMR spectroscopy of whether the one or more magnetically-labeled biological objects is/are present in the fluid.

Abstract: It is intended to provide a supersensitive, quick and accurate method for biochemical analysis. The method includes: adding magnetic fine particles into a solution containing a target substance, whereby a first substance for detection immobilized on the magnetic fine particle is bound to the target substance, while aggregating the magnetic fine particles so as to form an aggregate in the solution; next binding the target substance bound with the magnetic fine particle constituting the aggregate to a second substance for detection on a magnetic sensor layer so as to immobilize the aggregate onto the surface of the magnetic sensor layer; and measuring a magnetic stray field of this aggregate using a magnetic sensor.

Abstract: A device and method for measuring the surface level and/or the presence of a molten metal bath in a cooled container, particularly a crystalliser for a continuous casting process, comprising a source of an electromagnetic field, wherein said source of an electromagnetic field is a transmission coil fed with electrical energy at a predetermined frequency. The information on the level and/or the presence of said surface level is obtained by processing the total impedance (Z), as measured on said transmission coil, in order to calculate the contribution to said impedance (Z) of the currents induced in the walls of the crystalliser, which depend on temperature of the crystalliser and, from it, the value of said surface level and/or the presence of the molten metal bath.

Abstract: Accurate measurement cannot be performed due to magnetic signals from magnetic impurities included in a specimen container. By finding a difference between two measurement signals obtained by applying an external magnetic field for orientation to respective normal and reverse directions, the magnetic signals from the magnetic impurities included in the specimen container which are not dependent on the external magnetic field for orientation can be cancelled. The influence of the magnetic impurities included in the specimen container is reduced, and the signal of the intended bound magnetic marker can be measured with high sensitivity.

Abstract: A ferromagnetic thin-film based magnetic field detection system used for detecting the presence of selected molecular species. A magnetic field sensor supported on a substrate has a binding molecule layer positioned on a side thereof capable of selectively binding to the selected molecular species held on a magnetic particle. The magnetic field sensor can be substantially covered by an electrical insulating layer having a recess therein adjacent to the sensor in which the binding molecule layer is provided. A thin-film channel structure to the sensor is supported on the substrate that can be accompanied by a reservoir structure, and an electrical interconnection conductor is supported on the substrate at least in part between the sensor and the substrate, and is electrically connected to the sensor. The magnetic field sensor can be provided in a bridge circuit, and can be formed by a number of interconnected individual sensors.

Abstract: A fluid production computation apparatus using the electromagnetic induction theory is disclosed. In accordance with an embodiment of the present invention, the fluid production computation apparatus includes a line through which a current flows according to fluid production; a magnetic sensor, measuring magnetism induced by the current; and a fluid production computation unit, computing the fluid production through magnetism measured by the magnetic sensor. The conventional flow measurement apparatus measures the flow by measuring a current or a voltage induced by magnetism formed by a fluid or by using a fluid measurement sensor. However, with the present invention, an apparatus can be miniaturized and the measurement can be precisely performed by measuring a magnetic field induced by a current flowing according to fluid production.

Abstract: Technical field: analysis of mixtures, predominantly of biologic origin, for the contents of biological and/or chemical components, and analysis of mixtures, which parameters determine vital functions of biologic objects. Entity: spatially arranging a chosen component attached to magnetic particles, exposing the particles to a magnetic field, and recording a magnetic induction signal, from which the content of the analyte in the mixture is judged; this includes grouping the chosen component in a probe volume, making the magnetic field alternating, pre-setting its spectrum, at least, at two frequencies, and recording the signal at a frequency, which is a linear combination of these frequencies, during the exposure of the magnetic particles to the field.

Abstract: A magnetic sensor device is suggested. The magnetic sensor device comprises at least one magnetic field generator, a magnetic sensor element (8), means (17) for supplying a frequency modulated sense current to the magnetic sensor element (8). A rejection means (18) is arranged in the signal path between the magnetic sensor element (8) and an amplifier (11). The rejection means (18) is apt for rejecting a signal component at the modulation frequency. The rejection means (18) allows reducing the required dynamic range of the amplifier (11) significantly because a large part of the sensed signal carrying no measurement information is not transmitted to the amplifier (11).

Abstract: A ferromagnetic thin-film based magnetic field detection system having a substrate supporting a magnetic field sensor in a channel with a first electrical conductor supported on the substrate positioned at least in part along the channel gap and in direct contact with at least some surface of the magnetic field sensor and a second electrical conductor supported on the substrate positioned at least in part along the channel gap in a region thereof adjacent to, but separated from, the magnetic field sensor.

Abstract: A system for determining the magnetic permeability of a material is provided. Two electrical inductors formed as primary and secondary concentric coils share a common magnetic core space. An AC voltage applied to the primary coil creates a magnetic flux in the core proportional to the magnetic permeability of a sample of the material positioned within the core space. The magnetic flux induces an AC voltage in the secondary coil indicative of the sample magnetic permeability. When the material is a magnetorheological fluid, the magnetic permeability is proportional to the concentration of magnetic particles in the sample and can be back-calculated from the amplitude of the secondary voltage signal. Sensitivity and resolution can be increased by using two identical sets of coils wherein a reference material forms a core for the primary set and the MR fluid sample forms a core for the secondary set.

Abstract: A sensor for performing micro-conductivity measurements during well logging measurements in a borehole includes a magnetic core having a conductive insert wherein windings are driven with alternating current. Some embodiments include a sensor further having a conductive case. Various aspects of the sensor, such as dimensions and conductive properties of fabrication materials are selected to maximize performance of the sensor. Methods for using the sensor call for, among other things, placing the sensor in a well logging tool, and placing the tool in a well bore. A substantial focusing of the magnetic field on the wall of the borehole is achieved and provides for high quality data.

Abstract: A sensor device (15) for detecting magnetic particles (13) has a binding surface (40) with binding sites thereon and comprises: at least one sensor element (23) for detecting the presence of magnetic particles (13), means for attracting magnetic structures comprising at least one magnetic particle (13) toward and onto the binding surface (40) of the sensor device (15), and means for re-arranging and randomizing the position of individual magnetic particles (13) with respect to the binding sites on the binding surface (40) to give binding sites on all individual particles (13) a substantial probability to have a contact time with binding sites on the binding surface (40). With such sensor device (15), the speed of detection of target molecules in a fluid is enhanced.

Abstract: A non metallic flow through electrodeless conductivity sensor is provided with a conduit having primary and secondary process fluid flowpaths to form a fluid loop. At least one drive and one sense toroid surround the conduit on the fluid loop. Voltage supplied to the drive toroid induces a current in the sense toroid via the fluid loop to eliminate any need for metallic electrodes in contact with the process fluid. At least one additional drive and/or sense toroid is disposed on the fluid loop to enhance induction. Optionally one or more sense coils are disposed about the conduit outside of the fluid loop to cancel out stray electrical noise. An optional conductor disposed along the conduit detects any fluid leakage through changes in resistance thereof.

Abstract: A device for detecting electrically conductive particles in a liquid flowing in a pipe section, with a transmitter coil surrounding the pipe section for inducing eddy currents in the particles, at least one first inductive receiver coil surrounding the pipe section and a second inductive receiver coil which is spaced axially to the first receiver coil and which surrounds the pipe section, the first and the second receiver coils being located in the region of the transmitter coil and being subtractively connected, in order to output a difference signal according to the eddy currents induced by the transmitter coil, and the transmitter coil forming the primary side and the receiver coils forming the secondary side of a transformer arrangement. An evaluation unit evaluates the difference signal in order to detect passage of electrically conductive particles in the pipe section.

Abstract: An electromagnetic flowmeter calibration verification device for a flow tube comprises a first electrode, attachable to the flow tube, for transmitting, in use, a test current into the flow tube, and a second electrode, attachable to the flow tube, for receiving, in use, the test current transmitted through the flow tube. The device is arranged such that, in use, the test current, when passing from one electrode to another, passes through liquid in the flow tube. The device further comprises a third electrode, attachable to the flow tube, such that, in use, a voltage generated due to current distribution within the flow tube when the test current is passing within the tube is determined, and means for generating an output signal to a user if the voltage generated is outside a predetermined range. A method of verifying the calibration of an electromagnetic flowmeter for a flow tube is also provided.

Abstract: A detection device for detecting a target substance in a specimen comprises a flow channel for delivering the specimen, a coil surrounding the flow channel, and a reaction region being placed in a portion of the flow channel surrounded by the coil outside and holding a first trap substance immobilized thereon for trapping the target substance, the coil bring about a change of a physical property thereof when the target substance is trapped by the first trap substance and a magnetic body having a second trap substance on the surface thereof which second trap substance is capable of specifically binding to the target substance is trapped by the target substance.

Abstract: An apparatus and a method for monitoring a ratio of at least two components being mixed use sensors detecting ferrous taggant particles in the component(s) and the mixture. The sensors include an annular drive coil positioned between inner and outer annular sense coils all surrounding a passage for material being sensed. The ratio is determined by comparing a signal generated by one sensor through which a taggant particle containing component is flowing with a signal generated by another sensor through which the mixture is flowing delayed by the time required for the component to flow from the one sensor to the another sensor. The signals can also be used to control the flow of the components and to check the mixture after use.

Abstract: A sensor device (40) and a method for detection of the presence of at least one magnetic particle (46) are described. More particularly, a sensor device (40) comprising at least one magnetic field generating means (41) and at least one magnetic sensor element (42) is provided. The sensor device (40) furthermore comprises an exclusion zone (44), such as a spacer (44b) at the sensor surface (45), for excluding magnetic particles or beads (46) in the relative vicinity of the magnetic sensor element (42). The sensor device (40) according to the invention shows high depth or bulk sensitivity.

Abstract: A non metallic flow through electrodeless conductivity sensor is provided with a conduit having primary and secondary process fluid flow paths to form a fluid loop. At least one drive and one sense toroid surround the conduit on the fluid loop. Voltage supplied to the drive toroid induces a current in the sense toroid via the fluid loop to eliminate any need for metallic electrodes in contact with the process fluid. At least one additional drive and/or sense toroid is disposed on the fluid loop to enhance induction. Optionally one or more sense coils are disposed about the conduit outside of the fluid loop to cancel out stray electrical noise. An optional conductor disposed along the conduit detects any fluid leakage through changes in resistance thereof. A temperature detector is supported within an electrically non-conductive holder extending into the fluid flow path, so that the detector is free from physical contact with the fluid.

Abstract: An apparatus and a method for monitoring a ratio of at least two components being mixed uses sensors detecting ferrous taggant particles in the component(s) and the mixture. The sensors include an annular drive coil positioned between inner and outer annular sense coils all surrounding a passage for material being sensed. The ratio is determined by comparing a signal generated by one sensor through which a taggant particle containing component is flowing with a signal generated by another sensor through which the mixture is flowing delayed by the time required for the component to flow from the one sensor to the another sensor.

Abstract: Methods, Systems, and Devices for Evaluation of Thermal Treatment. A magnetically detectable particle and related methods, systems, and devices are provided for generating a temperature measurement for a batch or a continuous stream of material. The particle can include a first and second magnet each comprising a positive and negative pole. The particle can also include an adhesive having a release temperature and operable to attach one or both of the positive and negative poles of the first magnet proximate to the same polarity pole of the second magnet or to attach one of the positive and negative poles of the first magnet between the poles of the second magnet below the release temperature such that a first magnetic field is generated by the first and second magnet. The adhesive can also be operable to release the first and second magnets from one another above the release temperature.

Abstract: The present invention relates to a magnetoresistive sensing device, a system and a method for determining a density of magnetic particles in a fluid. The magnetoresistive sensing device has a substrate (1) with a layer structure (2) for supporting a fluid (3). The layer structure has a first surface area (4) in a first level and a second surface area (5) in another second level and a magnetoresistive element (6) for detecting the magnetic field of at least one magnetic particle (7) in the fluid, the magnetoresistive element being positioned near a transition (8) between the first and second surface area and facing at least one of the surface areas. A corresponding system and method is described as well.

Abstract: A measuring cell for use in apparatus for the measurement of the magnetic characteristics of a gas comprises means (5) defining a chamber (3) in which a test element (11) is suspended such as to be able to rotate about an axis, and means de inlet (1) and outlet port (4) means by which gas may flow through said chamber (3). The inlet port means is configured to cause the gas to flow in a substantially laminar flow regime. The chamber comprises a first portion (2) configured to cause the laminar gas flow to break up into a turbulent flow regime, and a second portion arranged to contain said test element. The gas flow enters from the first portion and enters the chamber in a flow pattern symmetrical in relation to the suspension position of the test element.

Abstract: A paramagnetic oxygen sensor and method employs a pressure sensor having a membrane extending through an air gap for a magnetic field. A piezoelectric element is mounted on the membrane. Gas chambers are formed on either side of the membrane. The gas mixture, the properties of which are to be measured, is supplied to one of the chambers. A reference gas is applied to the other chamber. A pulsating magnetic field is provided across the air gap and through the chambers containing the gas mixture and reference gas. The differing responses of the gas mixture and reference gas to the magnetic field deflect the membrane. The deflection of the membrane is sensed by the piezoelectric element. The piezoelectric element maybe operated either in a passive mode or active mode to sense the deflection of the membrane.

Abstract: A debris sensor arrangement is positioned within an enclosed body of fluid for detecting the presence of metallic debris particles therein. Debris detection involves exposure of cantilever beams to the fluid when magnetized within an electromagnetic field to attract the metallic debris particles thereon and induce vibratory motion thereof at a resonant frequency varied by changes in the density of the debris particles magnetically held thereon. Measurement of the resonance frequency reflecting the density of the debris particles within the fluid being tested thereby monitors the corresponding wear of machinery reflected by the debris density.

Abstract: A device for suspension of a sample body which rotates in space about a rotation axis which is in a fixed position or is related to a fixed position, as a function of the intensity of a measurement effect. In order to ensure that a sample mass is mounted in the device securely and such that it can rotate very largely without any lateral movement, the suspension, which has at least two springs, for the sample body is designed to be planar in a rest position.

Abstract: A removable particle collector for an apparatus which separates metal particles from lubricating oil. A valve assembly has a bore that provides a passage into the reservoir from outside. A valve element is normally biased against a valve seat to close the bore. A plug has a stem which when inserted into the valve assembly bore forces the valve element away from the valve seat. A portion of the stem is magnetized to attract ferromagnetic particles in the reservoir. A plurality of balls rotatably project from a surface on either the valve assembly or the plug and are received in a plurality of locking grooves in the other of the valve assembly and the plug to secure those components together. The balls are lubricated by fluid from the reservoir and can rotate to reduce wear which could loosen the components.

Abstract: A method and apparatus for measuring a predetermined parameter, by providing a displaceable sensor on a mounting member such that the displaceable sensor changes in location, form or length with respect to the mounting member in accordance with the predetermined parameter. A cyclically-repeating energy wave is transmitted to or through the displaceable sensor, and a predetermined fiducial point in the received cyclically-repeating energy wave is detected and used for continuously changing the frequency of the transmitted cyclically-repeating energy wave such that the number of waves received is a whole integer. The change in frequency is used to produce a measurement of the predetermined parameter. Several embodiments are described wherein the displaceable sensor is a deformable membrane, an end wall of a bellows, a spring-mounted member, a displaceable plunger, and a bar changing its length in accordance with the parameter to be measured.

Abstract: A measuring head for the determination of the concentration of a paramagnetic gas in a gas sample has first and second housing parts (21, 2) made of a steel alloy for accommodating a magnet coil body (4, 5) each. The magnet coil bodies extend concentrically around the central axis of each housing part (21, 2). Metallic bars (31, 3), which are used as magnet poles for the measuring head, are located at spaced locations with a defined air gap in the assembled state of the measuring head. The bars are arranged in the center of the measuring head in the area of the central axis of the housing parts (21, 2). A sample gas cuvette support (6) is provided in the air gap between the housing parts (21, 2) for positioning a sample gas cuvette holder (1). The sample gas cuvette support (6) is provided with a gas inlet and gas outlet (8, 81).

Abstract: An apparatus is provided for quantitatively measuring samples whose amount or other characteristic quality is to be determined. The samples are arranged in a predefined pattern and are excited in a magnetic field. The magnetizations of the magnetic particles are thereby caused to oscillate at the excitation frequency in the manner of a dipole to create their own fields. These fields are inductively coupled to at least one substantially flat sensor such as sensing coils fabricated in a gradiometer configuration.

Abstract: A method for evaluating measuring signals of an electromagnetic field is disclosed which is in interaction with an electrically conductive fluid for detecting components in the fluid which differ from the electric conductivity of the fluid, with the measuring signals being divided into at least two channels and being evaluated in order to detect different distributions and concentrations in the fluid.

Abstract: The present invention concerns a method and a device for machine diagnosis and, in particular, for transmission diagnosis in a machine or motor vehicle. The measurement system, according to the invention, comprises a coil (2) wound on a coil core (11), on the surface of which ferritic wear particles (3) to be detected accumulate. Opposite the coil (2) a rotating toothed wheel (6) is arranged which influences the inductance of the coil (2). The output signal of the coil (2) is pulsed with a constant amplitude, the pulse frequency depends on the rotation speed of the toothed wheel (6). Deviations of the amplitude are attributable to the accumulation of ferritic wear particles (3) on the coil (2) and therefore provide a measurement of the condition of the machine or transmission.

Abstract: A non-ferrous component comprising a thermally-affected adhesive applied to a surface of the component, and at least one ferrous metal wire attached to the surface of the component by the thermally-affected adhesive.

Abstract: A method for detecting changes of magnetic response of at least one magnetic particle provided with a external layer in a carrier fluid, comprising measuring the characteristic rotation time of the magnetic particle with respect to the external layer, and measuring Brownian relaxation in the carrier fluid under the influence of an external alternating magnetic field. The method implies that upon modification of the effective volume of the particle or its interaction with the carrier fluid, a hydrodynamic volume of the particle changes, which implies a change of the frequency (ƒmax) at which an out of phase component of the magnetic susceptibility has its maximum.

Abstract: A method for evaluating measuring signals of an electromagnetic field is disclosed which is in interaction with an electrically conductive fluid for detecting components in the fluid which differ from the electric conductivity of the fluid, with the measuring signals being divided into at least two channels and being evaluated in order to detect different distributions and concentrations in the fluid.

Abstract: In a preferred embodiment, a sensor (10) for measuring magnitude and polarity of static charge on particles in a liquid, including: an electrically nonconductive conduit (26) through which the particles and the liquid can flow; a magnet (20) having first and second legs (22,24) with a gap therebetween, the gap being disposed in the conduit; and three electrodes (40, 42, 44) insulatedly disposed in the first leg and having distal ends protruding into the gap. A method of measuring magnitude and polarity of static charge on particles in a liquid is also provided.

Abstract: A method of generating a residence time measurement of a particulate-containing food product while passing the product as a continuous stream through a thermal processing apparatus is described. The method includes the steps of inserting at least one detectable particle, and preferably many detectable particles, tagged with at least one magnetic implant into the stream at pre-selected intervals; detecting the at least one implant using at least one sensor located at a detection point downstream from a location of the inserting of the at least one detectable particle; determining a time of passage of the at least one detectable particle in the stream using output from the at least one sensor; and generating a residence time measurement for the stream using the time of passage for the at least one detectable particle. The method also includes the use of multiple sensors for detecting the implants. A suitable system and detectable particle for carrying the method are also described.

Abstract: A method for inspecting pipe, the method, in at least certain aspects, including detecting an inspection parameter in at least a first part of a pipe, the pipe having a length, a hollow body, an outer surface, and a generally circular pipe wall with an inner diameter and an outer diameter, locating at a first location the first part of the pipe with respect to the length of the pipe and with respect to the outer diameter of the pipe; and such a method for inspecting pipe which, in at least certain aspects, includes detecting at least a first part of a first imperfection of the pipe.

Abstract: A measuring device for determining the oxygen content in gases is described. The measuring device is disposed between two magnets that are positioned at a distance from one another. The measuring device is equipped with a sensor that is held rotatably within a frame. The sensor has two parallelepipedic bodies that are both made hollow or solid and are connected to one another via a web-shaped structural element. The web-shaped structural element is fastened to the frame via at least one holding element, so that the sensor can be rotated about its center of gravity. The amount of rotation is dependent on the quantity of oxygen that is concentrated between the two magnets. A current can be conducted through a conductor track led on the surface of the sensor and generates a correspondingly high restoring force by which the sensor is brought into the position of rest again.

Abstract: A method and system for measuring anchoring strength of liquid crystal through measurement of magnetic field induced torque. In the system for measuring anchoring strength of liquid crystal, when a magnetic field (7) is applied to a liquid crystal cell (1), a torsion wire (5) twists in response to the magnetic field (7) As a result, a mirror (6) attached to the torsion wire (5) displaces, and thus a laser beam emitted from a laser (8) and reflected from the mirror (6) rotates. The displacement of the laser beam is detected by a bisected photodiode (9) for position detection. Specifically, outputs from the bisected photodiode (9) are amplified by means of amplifiers (10) and (11), which output voltages VA and VB, respectively. The magnetic-field induced torque is proportional to the rotational angle of the mirror, which is proportional to VA-VB.

Abstract: The present invention concerns a method and a device for machine diagnosis and, in particular, for transmission diagnosis in a machine or motor vehicle. The measurement system, according to the invention, comprises a coil (2) wound on a coil core (11), on the surface of which ferritic wear particles (3) to be detected accumulate. Opposite the coil (2) a rotating toothed wheel (6) is arranged which influences the inductance of the coil (2). The output signal of the coil (2) is pulsed with a constant amplitude, the pulse frequency depends on the rotation speed of the toothed wheel (6). Deviations of the amplitude are attributable to the accumulation of ferritic wear particles (3) on the coil (2) and therefore provide a measurement of the condition of the machine or transmission.

Abstract: In a device for measuring the filling level, thermoelements (20) are used which are disposed on a sheet-shaped support (25). The thermoelements (20) consist of two different materials and are disposed in two rows (71, 72) placed side by side. Two adjacent thermoelements (20) of said rows (71, 72) have a common junction point (23) that is heated. Both rows (71, 72) of thermoelements also have two additional junction points that are cold. A first group of thermoelements (20) is disposed with their supports (25) in the interior of the container and operate as measuring detectors. A second group of thermoelements (20) serves as reference sensors since they regulate the heat flow impinging upon the junctions points (23) relative to a defined reference voltage.

Abstract: A method of determining the level of a medium in a container by generating a constant magnetic field in the container, exciting an elongated sensor element to longitudinal oscillations, the sensor element being secured on one end in the container and containing a magnetostrictive material, measuring the resonant frequency of the sensor element, or the damping of the longitudinal oscillation, by means of periodically varying magnetization of the sensor element in the constant magnetic field, and determining the fill level from the resonant frequency or from the damping of the longitudinal oscillations.

Abstract: A system and method for monitoring the composition of a magnetically permeable material, where the system comprises a first container containing a volume of magnetically permeable material; a flow path for flowing the magnetically permeable material out of the container; a sensor for determining the inductance of the magnetically permeable material; and a sensor for determining the density of the magnetically permeable material. The sensors for determining the density and inductance of the magnetically permeable material are flow connected to the flow path.

Abstract: The present invention relates to a method for detecting changes of magnetic response of at least one magnetic particle provided with an external layer in a carrier fluid, wherein the method comprises using a measuring method comprising measuring the characteristic rotation time of said magnetic particle with respect to said external layer, which measuring method involves measuring Brownian relaxation in said carrier fluid under the influence of an external alternating magnetic field. The method implies that upon modification of the effective volume of the particle or its interaction with the carrier fluid a hydrodynamic volume of the particle changes, which implies a change of the frequency (fmax) where an out of phase component of the magnetic susceptibility has its maximum.

Abstract: A method to maintain magnetic levitation that is stabilized by means of Hall effect sensors is disclosed. The method and device comprising a Hall effect sensor or sensors used to control an electromagnet to maintain the position between two magnets or objects. The present invention has been used to suspend a magnet in a high pressure tube that is magnetically coupled to a magnet outside the tube connected to an analytical balance that can accurately measure the force on the magnet inside the tube. This force measurement can be used to determine fluid density, flow, viscosity, and solubility. This magnetic levitation method also has application for other devices such as motors, generators, trains, turbines, wind tunnels, and entertainment devices.

Abstract: An apparatus is provided for quantitatively determining amounts and identities of substances whithin patterns of magnetic particles, such as within lateral flow membranes, microfludic systems, and the like. Magnetic particles are complexed with substances to be determined and are excited in an oscillating magnetic field. The magnetizations of the magnetic particles are thereby caused to oscillate at the excitation frequency to create their own fields. These fields are inductively coupled to at least one sensor such as sensing coils fabricated in a gradiometer configuration. The output signals from the sensing coils are appropriately amplified and processed to provide useful output indications.

Abstract: Method and device for monitoring an insulating or conducting test fluid for acidity, basicity, contaminants and/or specific chemicals by monitoring the rate of modification, for example corrosion, dissolution or erosion of at least one plate of a capacitive sensor immersed in the fluid. The sensor's dielectric element is inorganic or piezoelectrically active ceramic. Capacitor plates can be different materials, foil or coated/deposited metals modified by the test fluid. Capacitance is measured over time, its change due to modification of sensor plate area is recorded and used to determine quantity of acid, alkali, contaminants and/or chemicals in the test fluid. Piezoceramic dielectric allows the detector to be vibrated. The sensor can be attached to an ultrasonic transducer. Presence of specific chemicals requires a chemically non-reactive and a chemically reactive electrode re the chemical of interest. If the test fluid is conductive, the changed capacitance is measured in an insulating fluid.