Abstract: Certain aspects of the present disclosure provide methods and apparatus for performing electron paramagnetic resonance (EPR) spectroscopy on a fluid from a flowing well, such as fluid from hydrocarbon recovery operations flowing in a downhole tubular, wellhead, or pipeline. One example method generally includes, for a first EPR iteration, performing a first frequency sweep of discrete electromagnetic frequencies on a cavity containing the fluid; determining first parameter values of reflected signals from the first frequency sweep; selecting a first discrete frequency corresponding to one of the first parameter values that is less than a threshold value; activating a first electromagnetic field in the fluid at the first discrete frequency; and while the first electromagnetic field is activated, performing a first DC magnetic field sweep to generate a first EPR spectrum.

Abstract: A method of probing printed circuit boards that includes providing a circuit board design including a plurality of probe points, and selecting a probe point including a location ink from the plurality of probe points in the circuit board design to be probed on a physical printed circuit board design. The method continues with probing at least one probe point of the plurality of probe points with a probe that activates the location ink. Activation of the location ink by the probe indicates the selected probe point including the locating ink.

Abstract: A method is provided that includes acquiring coil data from a magnetic resonance imaging device. The coil data includes undersampled k-space data. The method includes processing the coil data using an image reconstruction technique to generate an initial undersampled image. The method includes generating a reconstructed image based on the coil data, the initial undersampled image, and multiple iterative blocks of a residual deep-learning image reconstruction network. A first iterative block of the residual deep-learning image reconstruction network receives the initial undersampled image. Each of the multiple iterative blocks includes a data-consistency unit that preserves the fidelity of the coil data in a respective output of a respective iterative block utilizing zeroed data consistency. The initial undersampled image is added to an output of the last iterative block via a residual connection.

Abstract: Various methods and systems are provided for correcting transmit attenuation of an amplifier of a transmit radio frequency (RF) coil for use in a magnetic resonance imaging (MRI) system. In one example, a method includes setting a reference value of transmit attenuation for an amplifier of a transmit radio frequency (RF) coil, acquiring a two-dimensional B1 field map with the transmit attenuation set at the reference value, determining a mean flip angle from the B1 field map, determining a transmit attenuation correction value based on a prescribed flip angle and the mean flip angle, correcting the reference value of transmit attenuation with the transmit attenuation correction value to obtain a final value of transmit attenuation, and performing an MRI scan with the transmit attenuation set at the value.

Abstract: A method for mapping geological structures of a formation on a side of a surface, includes: generating a magnetic moment using at least one magnetic moment generator to build up a magnetic field in the formation in an on-period, wherein the magnetic moment has a moment strength, and wherein the magnetic moment is positioned on another side of the surface; changing the magnetic moment to change the magnetic field; and making at least one record in a recording device at a recording time trecord in an off-period, wherein the record includes at least a representation of the change in the magnetic field and/or a representation of the magnetic field obtained by a B/E-measuring unit; wherein the on-period is separated from the off-period by the act of changing the magnetic moment.

Abstract: A logging tool includes a mandrel having an axis, a bobbin positioned about the circumference of the mandrel, and defining a first cross slot at a first slot angle and a second cross slot at a second slot angle opposite the first slot angle. The first and second cross slots intersect each other. The tool includes a first antenna in the first slot and including a first plurality of windings wrapped about the mandrel, a second antenna co-located with the first antenna and in the second slot, and an antenna shield secured to the tool mandrel and in each of the first and second slots. The first antenna is arranged in a first orientation and at a first winding angle. The second antenna is arranged in a second orientation and at a second winding angle.

Abstract: A medical instrument may comprise a flexible shaft and a sensing coil extending within the flexible shaft. The sensing coil may include an electrical conductor wound around a flexible core. The flexible core may comprise adjacent flexible pieces of magnetically permeable material that are configured to slide relative to each other in response to a bending of the flexible core.

Abstract: A magnetic field sensor comprises a first coil configured to generate a magnetic field having a first frequency and induce a reflected magnetic field from a target. A second coil configured to generate a diagnostic magnetic field having a second frequency is included. The diagnostic magnetic field is configured not to induce a reflected magnetic field from the target that is measurable by the magnetic field sensor. At least two magnetic field sensing elements detect the reflected magnetic field and the diagnostic magnetic field and generate a signal representing the reflected magnetic field and the diagnostic magnetic field. A processing circuit is coupled to the at least two magnetic field sensing elements and configured to receive the signal, extract a diagnostic magnetic field portion of the signal representing the diagnostic magnetic field, and generate an error signal if a fault is detected.

Abstract: A cable for operating a gradient coil of a magnetic resonance apparatus, a magnetic resonance apparatus, and a method for manufacturing a cable for operating a gradient coil of a magnetic resonance apparatus are provided. The cable includes at least one electric conductor and a stabilizing sheathing that surrounds the at least one electric conductor at least partially.

Abstract: A stress compensation control circuit of the present invention is provided which is capable of using a compensation error similar to that at room temperature even at a high temperature and reducing the area of a chip for a semiconductor sensor as compared with the related art. The stress compensation control circuit compensates for a change in detection sensitivity due to a stress to be applied to the semiconductor sensor. The stress compensation control circuit includes a stress compensation voltage generating circuit generating a stress compensation voltage corresponding to the applied stress in accordance with a difference between changes in transconductance due to stresses in a first depletion transistor and a first enhancement transistor, and performs compensation for the detection sensitivity in correspondence to the stress applied to the semiconductor sensor.

Abstract: Described are tools, systems, and methods for dielectric logging using transient waveforms. In some embodiments, one or more microstrip antennas are employed for the measurements. In various embodiments, the waveforms are processed in the time-domain to determine the dielectric properties of a formation, from which geophysical formation properties can then be derived. Further embodiments are disclosed.

Abstract: A logging tool includes a mandrel having a tool axis, a first loop antenna including first windings wrapped about the mandrel, a second loop antenna co-located with the first loop antenna and including second windings wrapped about the mandrel, and a shield secured to the mandrel. The first loop antenna is in a first orientation and the first windings are wrapped at a first angle. The second loop antenna is in a second orientation opposite the first orientation and the second windings are wrapped at a second angle. The shield includes first slots overlapping and along the first loop antenna and second slots overlapping and along the second loop antenna. The first slots define a first trace angle with respect to the tool axis and different from the first angle. The second slots defines a second trace angle with respect to the tool axis and different from the first angle.

Abstract: A method and system for determining a position of a second production wellbore. The method may comprise inducing a first current into a first conductive member with a first source, emitting a first magnetic field generated by the first current from the first conductive member into a formation, inducing a second current into a second conductive member with a second source, emitting a second magnetic field generated by the second current from the second conductive member into the formation, disposing an electromagnetic sensor system into the second production wellbore, recording the first magnetic field with the at least one sensor from the formation, and recording the second magnetic field with the at least one sensor from the formation. The system may comprise a first source, an electromagnetic sensor system, at least one sensor and an information handling system configured to determine the position of the second production wellbore.

Abstract: According to an aspect of the present inventive concept, there is provided a method of extracting information about a sample, the method comprising: performing a plurality of magnetic resonance measurements on the sample, each measurement including subjecting the sample to an encoding sequence, at least a part of the sequence being adapted to encode a magnetic resonance signal attenuation due to nuclear relaxation and diffusion, wherein at least one parameter of a gradient pulse sequence is varied between at least a subset of said plurality of measurements, and at least one measurement of said subset includes a gradient pulse sequence having a diffusion-encoding tensor representation with more than one non-zero eigenvalue, and wherein at least a subset of said plurality of measurements include encoding for different levels of magnetic resonance signal attenuation due to nuclear relaxation; and extracting information about the sample from signals resulting from said plurality of magnetic resonance measurements

Abstract: According to one embodiment, a magnetic resonance imaging apparatus includes an amplifier, a gradient coil, and adjusting circuitry. The amplifier includes pulse width modulation circuitry modulating a pulse width of a driving signal, which is input to switching elements, in accordance with an input of a control signal corresponding to a waveform of a gradient magnetic field. The gradient coil generates the gradient magnetic field by an electric current supplied in accordance with an output voltage which is output from the amplifier. The adjusting circuitry executes adjustment of a gain of the amplifier, which is included in the control signal, or adjustment of the pulse width of the driving signal, in accordance with a dead time included in a switching cycle of the switching elements.

Abstract: Methods and apparatus for detecting water in multiphase flows are disclosed. An example apparatus includes a conduit including an inlet to receive a multiphase flow and an electromagnetic sensor coupled to a liquid-rich region of the conduit to measure a permittivity of the multiphase flow, and a water detection manager to determine that water is detected in the multiphase flow based on the permittivity.

Abstract: The MRI apparatus includes a processor configured to apply a gradient echo pulse sequence that makes a sum of gradients applied during one repetition time (TR) in a slice selection direction, a phase encoding direction, and a frequency encoding direction equal zero and maintains spins in an object in a steady state; alternately apply, while the gradient echo pulse sequence is continuously applied, a first radio frequency (RF) pulse having a first flip angle and a second RF pulse having a second flip angle that is different from the first flip angle at each TR interval; and generate an MR image based on an echo signal acquired when the spins are in the steady state.

Abstract: An NMR system includes a radio frequency (RF) NMR application-specific integrated circuit (ASIC) chip configured to generate an RF output signal and a rectifier configured to receive the RF output signal and convert the RF output signal to (a) a direct current (DC) pulsed field gradient (PFG) signal or (b) a DC trigger signal for at least one of (i) activating at least one component of an NMR system external to the NMR RF ASIC chip and (ii) synchronizing at least one component of an NMR system external to the NMR RF ASIC chip.

Abstract: A device for securing aircraft wiring, monitoring the aircraft wiring, and detecting degradation of the aircraft wiring includes a first clamp body and a sensing device. The first clamp body has a first end, a second end opposite the first end, a concave portion extending semi-annularly between the first end and the second end, a first exterior surface, and a second exterior surface opposite the first exterior surface, the concave portion configured to at least partially define a wire-receiving space. The sensing device is adjacent the wire receiving space and is configured to sense a characteristic of the aircraft wiring indicative of integrity of the aircraft wiring. A wireless module can be configured to communicate data from the sensing device to a receiver. An electronics housing can support the sensing device and/or other electronics, and can releasably mate and fasten to the first clamp body.

Abstract: A plurality of stimulations is transmitted to tissue or other material using one or more transmitters. The plurality of signals associated with the excited tissue and the transmitted stimulations are measured. The measured signals are processed to generate field-related quantities, such as B1+ and/or MR signal maps. Field-related quantities are generated also from simulation, by calculating the one or more incident fields from a simulator model of the one or more transmitters and assuming a given distribution of electrical properties in the tissue or other material. Field-related quantities generated from simulation and experimental procedures are compared to each other. The assumed electrical properties distribution is updated and the procedure is repeated iteratively until the difference between simulated and experimental field-related quantities is smaller than a threshold.