Abstract: An x-ray generator including a light source; a high temperature photocathode arranged so as to be illuminated by light from the light source; an accelerator for accelerating electrons emitted by the photocathode; and a target onto which accelerated electrons impinge so as to produce x-rays, the target being held at substantially ground potential. The accelerator is arranged so that the photocathode is at a low voltage end of a voltage multiplier, typically held at about -100 kV, and the target is at the high voltage end at ground potential. The voltage multiplier can include a bank of nested tubular capacitor members which surround the photocathode and accelerator section and are arranged such that the outer surface is at ground potential, the same as the target.

Abstract: A portable interface for one or more electronic smart cards (74, 76), the interface being pluggable in a card reader, and comprising a module (80) that is designed to be received in the card reader and having at one end pluggable means (16) for making electrical connection with the card reader, an endpiece (18, 46, 78) secured to the other end of the module (10, 80) and including a slot (24, 48, 50) for insertion of the smart card, a housing (82, 84) designed to receive at least a portion of the smart card and passing through at least a portion of said endpiece, said housing guide and positioning means (101, 103, 102, 104) for the smart card, and electrical connection means (86, 96) for making electrical connection with the electrical contact tabs of the smart card.

Abstract: An NMR pulse sequence technique for use in the borehole environment is provided which uses CPMG pulses according to?W.sub.i -90-(t.sub.cp -180-t.sub.cp -echo).sub.j !.sub.iwhere j is the index of the CPMG echoes gathered, i is the index of the wait times in the pulse sequence, W.sub.i are the varying wait times before the CPMG pulses, and tcp is the Carr-Purcell spacing. Measurements are made of the signals induced in the formation as a result of the magnetic fields to find the spin-echo relaxation time T1. Using T1, the gas effect on formation parameters may be derived. Also, gas saturation and gas chemical composition can be derived. In addition, the diffusion coefficient of gas under reservoir conditions can be more than ten times larger than that of water, making the T.sub.2 relaxation time of gas more sensitive to static magnetic field gradients. In formations where gas occupies pores larger than about 10 .mu.m, this T.sub.2 effect (effect of diffusion on the measured T.sub.

Abstract: A portion of a borehole wall is isolated from surrounding borehole fluids by placing a chamber of a borehole tool against the borehole wall. The chamber comprises a cylindrical recess in an exterior surface of the borehole tool. The recess is open at one end to receive borehole fluids, and closed at the opposite end by a concave ultrasonic acoustic transducer. Mudcake present within the chamber and on the isolated portion of the borehole wall is disintegrated by the concave ultrasonic transducer. This approach can be used to remove mudcake from a borehole wall with a moving or stationary borehole tool.

Abstract: An active filter for compensation of polluting harmonics on an electricity distribution network comprising a source of energy (19, 20), a bridge converter (21) connected between the energy source and the network, control means which control the bridge converter in order to compensate for the polluting harmonics, characterized in that the state of the energy source (19, 20) is independant of the control of the bridge converter carried out by the control means (22) and in that the control means (22) control the injection of the harmonic components independantly of the state of the energy source.

Abstract: Images of rock formations below the earth's surface can be obtained on a microscopic scale. A borehole tool uses a seal to isolate an interval of the formation from borehole fluids which are outside the seal. A probe of the tool engages a wall of the formation and then draws formation fluid from the formation into the interior of the tool. The tool then produces an optical image of the formation which indicates rock texture. The seal can comprise a pad, inflatable packers, compressional packers, or cement plugs. The images of the formation can be obtained with electro-optic imagers such as charge-coupled devices (CCD) or a camera operating in the visible and/or near infrared range, or with ultrasonic transducers operating in the sub-MHz to mid GHz range, for example. The near infrared range provides an optical image of the formation through opaque fluids such as oil based muds or oil itself.

Abstract: A method for producing lutetium oxyorthosilicate crystals includes maintaining the interface between a crystal and the melt from which it is pulled substantially flat as the crystal is grown. In a Czochralski growth method, the rate of rotation of the crystal and its diameter are typically controllable to provide the flat interface as the crystal is pulled. Crystals produced by this method exhibit less variability in scintillation behavior so making them particularly suitable for spectroscopic uses. Such crystals find uses in borehole logging tools.

Abstract: A method and apparatus for transmitting data from a monitoring station using frequency hopping and interval hopping as described. The output frequency of a transmitter in the monitoring station is hopped between selected output frequencies by retrieving random numbers from a table, generating a control voltage corresponding to the retrieved random number, applying the control voltage to an RF oscillator and transmitting a signal from a transmitter in the monitoring station using the signal from the RF oscillator as a carrier. The output frequency of the transmitter is limited between a maximum output frequency and a minimum output frequency by comparing the retrieved random number to data limits stored in a memory in the transmitter and rejecting retrieved random numbers outside of the retrieved limits. Interval hopping is realized by selecting a random number from the random number table, multiplying the random number by a fixed increment and adding the product to a minimum time interval.

Abstract: The invention provides a fluidic oscillator which is symmetrical about a longitudinal plane of symmetry (P), the oscillator comprising means for generating an oscillating two-dimensional fluid jet, an obstacle provided in its front portion with a cavity that is swept by the oscillating jet, and a longitudinal element disposed in the empty space situated downstream from said obstacle in such a manner as to partially subdivide said space into two identical zones, and to form between them at least one communication channel for the fluid. The invention also provides a fluid flow meter including such a fluidic oscillator.

Abstract: A bracket for use in a meter head of a rotary gas meter supports and secures a plurality of meter components, which have traditionally been mounted in separate housings. The bracket has a first pair of opposing slots for receiving a processor printed circuit board (PCB) and a second pair of slots for receiving a liquid crystal display PCB. The PCBs are held in place with a pair of screws extending through the bracket and through the PCBs. The bracket defines a walled enclosure within which a battery pack may be received. The rear portion of the bracket has legs for mounting the bracket to a metal plate located at a rear portion of the rotary gas meter. The legs also space the walled enclosure and the processor PCB from the metal plate so that some mechanical gearing may be received between the bracket and the metal plate. The processor PCB receives inputs from a reed switch, pressure transducer, and temperature sensor, all of which are located within the rotary head.

Abstract: An integral electronic meter system diagnostics package including a microprocessor, storage memory, pre-select series of system diagnostic tests, and recording any results which exceed predefined programmable thresholds, and display means for displaying error and/or diagnostic messages identifying selected diagnostic data and/or errors discovered in the meter tests during a predefined period. The system automatically senses the type of electrical service in which the meter is installed.

Abstract: A permanent magnet of a pulsed nuclear magnetic resonance (NMR) device is positioned within a drill collar for evaluating earth formations. In this way, the torsional and bending strengths of the drill collar are maximized with relatively little sacrifice of the magnetic moment of the permanent magnet. The resulting tool makes NMR measurements while the formation is being drilled. An antenna for producing and detecting an oscillating RF field in the earth formation is either located in a groove in the outer surface of the drill collar, or in an alternative embodiment, the drill collar itself serves as an RF antenna.

Abstract: A method and apparatus for interactively tuning a transmitter for use in a monitoring station is described. The monitor includes a voltage controlled oscillator producing a radiowave signal for use as a carrier. The voltage used to control the voltage controlled oscillator is provided by a voltage supply that produces an output voltage corresponding to an input data stream. The tuning station provides test data streams to the voltage supply and monitors the output frequencies of the transmitter to determine when the output frequency of the transmitter is above or below the maximum allowable output frequencies. When data streams corresponding to the maximum and minimum output frequencies are determined, they are stored in a memory in the monitoring station and a complete table of temperature-compensated data is generated based upon typical unit temperature drifts. The entire table is loaded into the monitoring station to provide maximum and minimum data sequences for various operating temperature ranges.

Abstract: A method of controlling a device for producing or removing heat for the purpose of regulating the inside temperature of premises to comply with at least one reference q given in advance, in which, at each time instant that is separated from the following instant by a time interval .DELTA.t, a function J(u) is minimized over a duration T0 where J(u) characterizes the behavior of the inside temperature Ti of the premises, with:J(u)=.intg..sub.t.sup.t+T0 {qe.sup.2 +ru.sup.

Abstract: A radio antenna for mounting in the lid of a water meter box and forming part of a remote meter reading system comprises an annular conductive plate and a circular conductive plate which are coaxial with and parallel to each other and spaced apart to define a slot, the circular plate serving as a ground plate. The antenna has an input in the form of a conductive pillar interconnecting the two members, with a drive input at a selected point along the length of the pillar and a second input on the ground plate. A variable tuning capacitance is disposed between the plates diametrically opposite the conductive pillar. The ground plate also serves for locating the lid in undergrowth or under snow using a metal detector.

Abstract: A unidirectional register apparatus includes an input gear mechanism adapted to receive a rotational input from an external source; and a yoke, operatively coupled to the input gear mechanism, and arranged to pivot between a first predetermined position and a second predetermined position in response to a change in direction of the rotational input. Also provided are a first gear mechanism, attached to the yoke, which is arranged to produce a rotational output in the same direction as the rotational input; and a second gear mechanism, also attached to the yoke, which is arranged to produce a rotational output in a direction opposite to the rotational input. An output gear mechanism is provided which is alternately engageable with each of the first and second gear mechanisms. The output gear mechanism engages the first gear mechanism when the yoke is in the first predetermined position, and the output gear mechanism engages the second gear mechanism when the yoke is in the second predetermined position.

Abstract: A borehole logging tool comprises a Nuclear Magnetic Resonance (NMR) tool and is pulsed according to a selected Carr Purcell-Meiboom Gill (CPMG) sequence. Because the recovery time between CPMG sequences is short, the sequence acts as a filter such that signals induced by rapidly relaxing nuclei of fluid bound in an earth formation are detected. In this manner, the NMR tool gives a direct indication bound fluid volume and fast logging speeds are achieved.

Abstract: A gas meter includes a cam for driving first and second valve covers associated with respective diaphragms. Gas flowing into the gas meter is selectively directed by the first and second valve covers to reciprocate respective diaphragms. First and second cam rotation assemblies are coupled to respective diaphragms and continuously drive a cam to rotate the cam through a complete revolution, a feature which provides accurate metering of gas flows out of the gas meter, and a relatively steady flow of gas out of the gas meter. Further, the gas meter of this invention requires relatively few parts and so is relatively reliable and easy to manufacture.

Abstract: An improved method and apparatus for use with an underground tank of fire suppression fluid in which the fluid level within the tank can be visually determined quickly during pumping operations. Also, the fluid in the underground tank is protected from freezing by draining the fluid standing above the top of the tank. Protection against collapse or rapture of the underground tank is provided by a method of ventilating air into and out of the tank.

Abstract: A system for measuring the frequency of oscillation of the fluid in a fluid oscillator comprising detector means, a peak detector comprising a threshold device receiving a first signal from the detector means, means for storing the signal at the output of the threshold device and comparator means providing an output signal in accordance with the relative values of the first signal and the signal from the memory means.