Abstract: A device for measuring the cross section of the stator of a downhole motor having a carrier shaped to travel through the helicoidal interior of the stator and a sensor including first and second bending beam-strain gage structures for generating electrical signals indicative of the cross section of the stator.

Abstract: Machine for rapidly rotating and sensing imbalance of automotive drive shafts. Spindles including independent vibration sensors are rigidly secured to mounting blocks seated on a pair of rails integrally cast in a horizontal surface of a concrete base. A gear engaging a rack seated in a recess cast in the same horizontal surface senses to move one of the mounting blocks and its spindle and a plug also operable in the recess selectively locks the mounting block in position. Visual indicators are provided for simultaneously displaying vibrations sensed at each end of the driveshaft.

Abstract: For providing nuclear magnetic resonance equipment with reduced noise generation, gradient coils are disposed in the vacuum of the cryostat which accepts the superconducting magnetic coils for generating the fundamental field. Under given conditions, the radio-frequency transmission and reception coils or antennae are also located in the vacuum.

Abstract: In an examination method and apparatus utilizing nuclear magnetic resonance, high frequency pulses for producing nuclear magnetic resonance are applied by successively imposing a first 90.degree. pulse, a first 180.degree. pulse, a second 90.degree. pulse, and a second 180.degree. pulse substantially immediately after the second 90.degree. pulse, and a next pulse sequence is initiated upon elapse of a wait time after the second 180.degree. pulse has been applied. The wait time is rendered much shorter than the conventional prior art wait times for high speed scanning operation, by forcibly aligning magnetization M first with the direction of a -Z direction axis and then with the direction of a +Z direction axis, using the second 90.degree. pulse and the second 180.degree. pulse. By applying a number of first 180.degree. pulses, a number of nuclear magentic resonance signals are produced for additionally shortening the overall measurement time.

Abstract: An accelerometer is disclosed, which includes a flexible hinge, a base table fixed with one end of the flexible hinge, a pendulum fixed to the other end of said flexible hinge, torquers for producing a torque proportional to acceleration applied from the base table to the pendulum and a displacement detecting apparatus for electrically detecting a relative displacement between the fixed portion of the base table and the pendulum, wherein the base table is formed of first and second frames, the first frame is provided with an engagement portion for engaging with the second frame, a fixed portion for the flexible hinge, a fixed portion for the displacement detecting apparatus. In this case, the first frame is provided at its outer peripheral portion with an attaching flange portion and, one plane of the flange portion is used as an attaching reference plane for attaching the accelerometer to a body the acceleration of which is to be measured.

Abstract: A photoelastic transducer is constructed with a photoelastic element receiving a 45.degree. polarized light beam with a wave plate providing a 90.degree. phase displacement in its orthogonal components. The element has reflective surface coatings to produce multiple internal reflections so as to lengthen the optical path, and increase the sensitivity of the unit. Analysis of the orthogonal outputs can be according to the difference divided by the sum with one of the outputs being multiplied by the ratio of the D.C. component of the other output to its D.C. component, for the purpose of compensating for changes in tramsmission of the two signals.

Abstract: In an NMR imaging system, an image plane is scanned and NMR signals are collected over a plurality of image lines. The experiment is repeated, with the timing of the excitation pulses changed. Images are formed by performing Fourier transformations of the signal values. A ratio image is then formed by performing a complex division of the two images on a pixel by pixel basis. The ratio values cancel phase error effects in the image data and the use of complex numbers maintains the proper pixel polarity.

Abstract: In the production of nuclear magnetic resonance images, it is necessary to provide various magnetic fields with specified orientations and configurations in particular relationships with respect to a cylindrical coil form on which the RF and gradient coils are generally disposed. In particular, it is necessary to produce so-called transverse gradient fields which are oriented transversely with respect to the cylindrical form. It is necessary to produce a component parallel to the axis of the cylinder, but which component varies linearly in intensity in the direction transverse to the axis. That is to say, it is desirable to produce a magnetic field component within the cylinder such that surfaces on which this component is constant are parallel and are generally oriented parallel to the axis of the cylinder. Furthermore, for the purpose of providing proper spatial definition and resolution, it is necessary that this transverse field exhibit a highly linear variation in intensity inside the cylinder.

Abstract: Apparatus for removably connecting a strain cell to a polished rod of a well pumping unit and for preventing the development of strain cell output signals due to bending of the polished rod. The strain cell is connected to a frame member which can be clamped to the polished rod where strain cell output signals are obtained due to a change in tensile load on the rod. A pair of hinges, between the frame member and the polished rod, minimizes the development of strain cell output signals due to bending of the polished rod. The frame member can be adapted to mount on a variety of sizes of polished rods. The apparatus can be removed or replaced without the use of special skills or special equipment.

Abstract: A vibrational gyroscope is provided with a vibrating member in the form of a flexible annular shell extending from a flat flexible plate. In use, the flat plate is vibrated and excites radial vibrations in the lip of the annular shell. When the gyroscope is rotated about the shell axis, the nodes of these radial vibrations shift around the circumference of the lip, due to the action of Coriolis forces. The radial nodes of the vibrations in the plate shift similarly and their movement is detected by sensing means on the plate, giving an indication of the rotation rate.

Abstract: The invention relates to a coil arrangement for producing a homogeneous magnetic field especially for application to so-called NMR-imaging. An object of the invention is in terms of the size of a coil arrangement to expand the homogeneous area produced by a coil arrangement and, at the same time, to maintain the design of a coil arrangement simple and its manufacturing costs low. According to the invention, a coil arrangement includes three solenoids having a common axis, of which the axial winding width (W1) of the middlemost solenoid (1) is 2.75 . . . 2.95, preferably 2.835 . . . 2.855 times the mean radius (r1) of the middlemost solenoid (1) and the mean radius (r2) of the outermost solenoids (2) is 1.05 . . . 1.07, preferably 1.055 . . . 1.061 times the mean radius (r1) of the middlemost solenoid (1) and the axial winding width (W2) thereof is 0.32 . . . 0.38, preferably 0.340 . . . 0.342 times the mean radius (r1) of the middlemost solenoid (1).

Abstract: A measuring tube is inserted into a bore hole for measuring underground fluid pressure and is sealed against the bore hole wall for limiting the areas or regions in which the pressure measurement is to occur. A measuring cell is inserted into the measuring tube wall in each of these areas or regions and includes a mobile pressure sensing element against which acts the pressure of the medium surrounding the measuring tube. An end of the pressure sensing element projects into the inner space of the measuring tube and, for measurement, a measuring wheel of a measuring probe is brought into position underneath the end of the pressure sensing element such that the latter is moved radially outwards against the pressure exerted on it. The force which thus acts on the measuring wheel is determined by a measuring device for measuring the pressure. The medium to be measured does not enter or leak into the measuring tube since the measuring cell is sealingly inserted into the measuring tube.

Abstract: An NMR apparatus capable of being used for both chemical analysis and imaging of a body without adjustment of the magnetic field strength of the magnet system used to define the equilibrium axis of magnetic alignment of the nuclei within the body. The apparatus incorporates two magnet systems each capable of independently defining an equilibrium axis of magnetic alignment for nuclei within a body to be examined by NMR techniques.

Abstract: Magnetic fields are applied to the examination subject, and the deflection of the atomic nuclei of the examination subject from their state of equilibrium by means of a high frequency magnetic excitation pulse is detected. There is at least one gradient coil for the purpose of generating a linear magnetic field gradient. The gradient coil is connected, in series with an additional inductance, to a current source. Connected in series with the gradient coil is a first switch. Connected in parallel with the series of connection of gradient coil and first switch is a second switch actuatable to open condition approximately simultaneously with the closure of the first switch.

Abstract: A shield for decoupling radio frequency (RF) and magnetic field gradient coils in an NMR apparatus is made up of first and second arrays of electrically conductive regions separated from one another by relatively narrow non-conductive regions. The arrays are disposed on opposite surfaces of a member formed of a high dielectric material. The conductive regions of one array are offset relative to the conductive regions of the other array such that the conductive regions of the one array bridge the non-conductive regions of the other array to form a plurality of capacitive elements. In operation, the capacitive elements act essentially as electrical short-circuits at radio frequencies, but transmit substantially unaffected the homogeneous magnetic field and audio frequencies associated with pulsed magnetic field gradients.

Abstract: A technique and apparatus for estimating in situ stresses by measuring stress-induced velocity anisotropy around a borehole. Two sets each of radially and tangentially polarized transducers are placed inside the hole with displacement directions either parallel or perpendicular to the principal stress directions. With this configuration, relative travel times are measured by both a pulsed phase-locked loop technique and a cross correlation of digitized waveforms. The biaxial velocity data is used to back-calculate the applied stress.

Abstract: A conventional magnetometer produces an output signal (10) which comprises a series of pulses (12, 14, 16). Each of these pulses has a beat frequency maximum. These pulses are input to a comparator (50) which makes a comparison to a threshold voltage V.sub.0 to produce a bi-level detected signal at a line (62). The detected signal is input to an integrator (52) which produces a series of pulses (78, 80, 82) corresponding respectively with the magnetometer output signal pulses (12, 14, 16). The two states of the detected signal corresponding to positive and negative integration. The time period for the positive integration is proportional to the beat frequency maximum time width period for the corresponding magnetometer output signal pulse. Thus the integrated pulses (78, 80, 82) have an amplitude which is a measure of the maxima time width periods for the corresponding magnetometer signal pulses.

Abstract: In the preferred and illustrated embodiment, a method and apparatus for measuring the flow of non-homogeneous materials in an incompletely filled channel is set forth. In one embodiment, a NMR (or ESR) flow meter arrangement including a magnet forming the requisite magnetic field H.sub.o across a flow channel is incorporated. The magnet cooperates with a coil providing an NMR or ESR output signal from selected specie(s) or sub-atomic patricles (i.e. nuclei or unpaired electrons) in the material in the flow stream. It is desirable for the signal to be representative of the total amount of material in the flow stream. This signal may be in error, unable to sort out prospective combined variations due to (1) incomplete filling of the sensing volume or (2) a non-homogeneous composition of material. A composition sensor coil inscribing a very small volume in selected portions of the flow channel is included to form an NMR output signal indicative of composition, the small volume being filled for that sensor.

Abstract: A piezoelectric sensitive element has elements for collecting charges appearing between the sides of the piezoelectric element. These elements include a flexible insulating strip having one the same face two distinct conductive layers each of which has an annular layer for contact with the piezoelectric sensitive element and connected by a connecting layer to a terminal layer. Application is to the detection of pinging in internal combustion engines.

Abstract: To reliably distinguish between knocking signals derived from an internal combustion engine knock sensor from all the other signals likewise derived from the knock sensor, which includes background noise signals, statistically distributed disturbance signals and the like, a correlation signal is generated, and the received signal is correlated with the correlation signal, which is cyclically varying at an average frequency which is of the frequency of the expected knocking signal, or a whole number multiple thereof. An output recognition is provided upon correlation between the correlation signal and the signal from the knocking sensor. The system can be implemented by a signal generator (6, 61, 62; 63) which provides the correlation signal, correlation being effected by an AND-gate (7, 71, 72; 73), or by software in a microprocessor in which an incoming knocking signal is interrogated in cadence with cyclical variation at the frequency which is the expected knocking frequency of the engine.