Abstract: A tennis racquet with a replaceable playing surface includes a frame, a cartridge, and a cartridge-lock with at least one key. The frame defines a cartridge support groove, a front upper half-oval bridge and a back upper half-oval bridge. Each bridge includes a head-guard. The front bridge with its head-guard and the back bridge with its head-guard define a planar passage way between the bridges. The cartridge includes a rim threaded with a string. The string defines a playing surface. The cartridge is shaped for removable snug fit in the support groove and in the planar passageway, such that when a replacement cartridge is snug within the frame, and when the at least one key is entered into the at least one key-aperture, the replacement cartridge is locked to the frame.

Abstract: A method for determining formation fluid pressure in earth formation surrounding a borehole wall uses a downhole probe coupled to a variable-volume cavity. The probe is driven into contact with formation at the borehole wall. The method includes expanding the volume of the cavity during a first period of time to establish fluid communication between tool fluid and formation fluid, by withdrawing a minimal amount of fluid from the formation. During a second period of time the tool pressure is allowed to equilibrate to formation pressure. When pressure equilibrium is established, formation fluid pressure is set equal to tool pressure. A preferred embodiment includes terminating expanding the volume of the cavity on detecting a break in the mud cake seal.

Abstract: A novel safety stopper for use with a conventional welding torch striker includes a sleeve made of a flexible, non-inflammable, heat-resistant material. The sleeve is shaped to enclose a central portion of both arms of a conventional welding torch striker, while allowing relative movement first and second push-tabs. The sleeve is retained on the arms by spring force. The sleeve is shaped to cover a substantial portion of the open area defined by the arms and the strike plate, while exposing the strike plate and the flint. A novel welding torch striker includes an integral safety stopper made of a flexible, non-flammable, heat-resistant rubber and formed as a web, a first handle-grip, and a second handle-grip. The stopper extends between both arms of the striker with the first handle-grip surrounding a portion of the first arm and the second handle-grip surrounding a portion of the second arm.

Abstract: Tube waves are used to locate and characterize a solids deposit inside a fluid-filled pipe. An acoustic tube wave pulse is transmitted along the pipe. On encountering a solids deposit, the tube wave pulse is perturbed and partially reflected by changes in the boundary conditions between the fluid and the pipe to produce two deposit-modified acoustic waves. One is a perturbed wave travelling in the same direction as the tube wave pulse. The other is a reflected wave travelling in the opposite direction. One of these deposit-modified acoustic waves is received to produce an acoustic signal. Accumulated acoustic signals are processed by Fast-Fourier Transform to produce frequency-based digital data. Phase data from the frequency-based digital data is inverted to produce slowness spectrum data. Power data from the frequency-based digital data is inverted to produce attenuation spectrum data. Spectrum data is used to locate a solids deposit in the pipe.

Abstract: The invention provides a method for determining phase transition pressure of downhole retrograde condensate. An OBM-contamination value is produced from a time-series of fluorescence values produced by measuring fluorescence emitted from a single-phase flow of OBM-contaminated formation fluid in a downhole cell during a cycle of time. The pressure of fluid in the cell is set at a transition boundary by incrementing drawdown pressure and monitoring the presence or absence of a phase transition. An apparent phase transition pressure value associated with the cycle of time is produced by setting apparent phase transition pressure value equal to cell pressure. This process is repeated for several cycles of time to produce a number of pairs of OBM-contamination value and apparent phase transition pressure value as OBM-contamination decreases over time.

Abstract: A distillation system is provided for batch thermolytic distillation of lump carbonaceous material, such as lump wood and shredded rubber tires. The system preferably includes multiple distillation units mounted side-by-side. Each unit includes a reactor bath for holding molten tin at approximately 455° C., a two-compartment reservoir for storing molten tin, and a porous basket pivotally mounted within the reactor bath for tipping motion. A process for batch thermolytic distillation of lump carbonaceous material includes rotating the porous basket into a reactor bath by rotating the basket about an axis passing through the reactor bath; putting a charge of wood into the basket; closing a retractable lid onto the reactor bath; filling the reactor bath with molten material to produce gas and char by thermolytic conversion of the charge, draining the reactor bath of molten material while the lid is closed; quenching the char in the reactor bath with steam; opening the lid; and tipping the char from the basket.

Abstract: Water-based mud filtrate concentration in a downhole fluid sample drawn from the borehole of an oil well is assessed. To measure water-based mud filtrate concentration, a water-based mud having a water-soluble fluorescent dye tracer is pumped into the borehole; sample fluid from a selected downhole location is pumped through a downhole flow line having a window; sample fluid flowing in an excitation region of the downhole flow line is illuminated through the window with fluorescence excitation light; and fluorescence emission from the excitation region is measured to produce a measured value. The measured value represents the fraction of water-based mud filtrate in the sample fluid. A calibration value is determined representing 100% water-based mud filtrate. A method for validating a sample of connate water as having an acceptably low WBM filtrate contamination tests for validation downhole, in real time.

Abstract: A first flux-loop inductive coupler element electrically couples with a second flux-loop inductive coupler element. The first flux-loop inductive coupler element comprises a first ring-like core having high magnetic permeability and a conical-section annular first face transverse to the plane of the first core. The first face has a first annular groove separating a first conical-section larger-diameter face and a first conical-section smaller-diameter face. A first coil is wound within the annular groove. The first and second cores form a low-reluctance closed magnetic path around the first coil and a second coil of the second flux-loop inductive coupler element. A first current-loop inductive coupler element electrically couples with a second current-loop inductive coupler element.

Abstract: An acoustic logging tool includes external baffle assemblies forming a waveguide structure at the acoustic source. The logging tool is designed for acoustic logging of earth formation surrounding a borehole. The external baffle assemblies form a waveguide structure that is designed to increase signal to noise ratio in an acoustic logging tool using dipole or other acoustic waves. In a preferred embodiment, the acoustic logging tool includes an elongated transmitter module, and a receiver sonde having a linear array of acoustic receivers. The transmitter module includes first and second cylindrical masses spaced apart along the axis by first and second spacers. The first cylindrical mass defines a first circular facing surface and a first cylindrical outer surface. The second cylindrical mass defines a second circular facing surface and a second cylindrical outer surface.

Abstract: A downhole connate water sample drawn from the formation surrounding a well is validated when mud filtrate concentration is acceptably low. A preferred method includes drilling the well with a water-based drilling fluid, or more generally a water-based mud (WBM), containing a water-soluble dye. The dye acts as a tracer to distinguish connate water from WBM filtrate in a downhole sample of formation fluid contaminated by mud filtrate from the water-based mud. Preferably, an optical analyzer in a sampling tool measures light transmitted through the downhole sample to produce optical density data indicative of dye concentration. Preferably, optical density is measured at a first wavelength to obtain a first optical density, and at a second wavelength, close in wavelength to the first wavelength, to obtain a second optical density. First and second optical density data are transmitted to the surface.

Abstract: Methods and tools are provided for real time velocity imaging of a borehole wall with sufficiently high resolution to identify vugs, worm holes, thin beds, dip angles, fractures and breakouts, for both open hole logging and logging while drilling in the presence of OBM's. A method is provided which includes transmitting an ultrasonic pulse through the borehole wall, receiving at first and second spaced-apart receivers an ultrasonic pulse refracted from the borehole wall, and producing a velocity image data value indicative of difference of arrival times at first and second spaced-apart receivers. This is repeated at a plurality of azimuths and depths to produce a velocity image data set. The method uses compressional pulses and/or pseudo-Raleigh pulses. A tool is provided for wireline use having an ultrasonic transmitter for transmitting ultrasonic pulses into the borehole wall, and a plurality of ultrasonic receivers.

Abstract: An acoustic transducer includes a polarized piezoelectric shell having a spiral-shaped surface. The acoustic transducer serves as a receiver or a transmitter. In one embodiment, the acoustic transducer includes a solid spiral shell having outer and inner spiral-shaped surfaces, and the shell is polarized, wired and packaged to operate in hydrophone-mode. In another embodiment, the acoustic transducer includes a shell defining an exterior spiral-shaped surface and a spiral slot; and the slot defines a closed cavity with an interior spiral-shaped surface. In a preferred bender-type receiver embodiment, the shell is polarized, wired, and packaged to operate in bender mode for maximum sensitivity and best low-frequency performance.

Abstract: A sonic logging tool that can be positioned within a fluid-filled borehole includes an axially distributed active vibration control system to reduce tool borne noise. The tool includes an acoustic transmitter, an axial array of acoustic receivers, and actuator assemblies that are coupled to cancel tool mode vibrations at stations along the receiver section of the tool. In a preferred embodiment, force is applied in feedback mode based on tool mode vibrations sensed at each station. The force at each station is applied by a real-time computational algorithm using feedback. The feedback includes weighting to accommodate monopole or dipole tool mode vibration. The computational algorithm includes FIR processing of signals received from a vibration sensor assembly. The force applied at a given station is a function of tool mode vibration measured at that station and the predetermined values of a set of FIR filter coefficients associated with the given station.

Abstract: A method and apparatus are provided for detecting a received acoustic pulse of a selected azimuthal borehole mode in a liquid-containing borehole in a formation. The method uses a sonde having an axial array of acoustic receiver stations aligned with the borehole, each receiver station having an azimuthal array of at least four piezoelectric receiver elements, the receiver elements uniformly spaced apart around the azimuthal array. An acoustic pulse transmitted within the borehole produces an electrical signal at each receiver element. Azimuthal spatial transform filtering is applied to produce data representing a received acoustic pulse of the selected azimuthal borehole mode. In one embodiment, azimuthal spatial DFT filtering is applied to digital data produced by analog to digital conversion. In another embodiment, cosine transform filtering is applied by an apodized receiver element.

Abstract: A yo-yo includes a first yo-yo half defining a first starburst, a second yo-yo half defining a second starburst, and an axle fixedly mounted between said yo-yo halves. The yo-yo also includes a roller bearing fixedly attached to the axle, and a spool fixedly attached to the roller bearing, the spool having a circumferential outer rim with a groove therein. A bearing pocket defines an annular radial gap between each yo-yo half and the outer rim, the gap sufficiently small that a string cannot wedge in the gap.

Abstract: A method provides for locating and measuring mechanical damage in rock surrounding a borehole by detecting one or both of reductions in ultrasonic compressional wave velocity in the rock as a function of azimuth, and by detecting focused acoustic energy in the rock from local increases in ultrasonic compressional wave amplitude resulting from velocity gradients. A first preferred embodiment uses a combination of azimuthal ultrasonic compressional wave velocity data and azimuthal ultrasonic compressional wave energy data. A second embodiment uses azimuthal ultrasonic compressional wave velocity data and omni-directional sonic velocity data, with a comparison test or a curve fitting test. A third embodiment uses azimuthal ultrasonic compressional wave energy data.

Abstract: A hair clip includes a formation defining an elongated base arm having two knobs, an elongated closure arm defining two apertures, and a hinge region connecting the arms for pivotal movement between open and closed positions. Each knob has a stem portion and a free end portion defining an end area with a peripheral acute angle flat-face detent. In a preferred embodiment, the hair clip, when closed, defines a passage for hair having several sharp bends, including acute angle 180° bends.

Abstract: A toy simulates an illuminated overhead moon with a long-legged spacecraft under it. The toy includes a lighting apparatus secured to a balloon by string under tension. The lighting apparatus, located wholly outside the balloon, illuminates the inside of the balloon so the balloon appears to glow. The lighting apparatus has at least three arms extending from a body having a locking fastener. The locking fastener is attached by string under tension to the neck of the balloon. Each arm terminates in a window for contacting the skin of the balloon and for transmitting light through the skin to the interior of the balloon. In a preferred embodiment, the lighting apparatus is of sufficiently low weight that the toy floats in air.

Abstract: A method for determining unknown stress parameters in earth formation measures velocities in four sonic transmissions modes (compression, fast shear, slow shear and Stoneley) at a series of depths. Relationships between measured velocities and other measured values, two independent linear constants, and three nonlinear constants associated with equations of motion for pre-stressed isotropic materials are expressed in a set of four or five velocity difference equations derived from non-linear continuum mechanics. The velocity difference equations are solved using inversion for useful stress parameters, including maximum horizontal stress, minimum horizontal stress, pore pressure, and change in pore pressure over time.

Abstract: A method and apparatus is provided for determining a quality of downhole fluid. A series of measurements are taken of at least one parameter of borehole fluid that is indicative of OBM filtrate contamination. By curve-fitting, the series of the measured parameter values are used to create an asymptotic curve indicative of the quality of the downhole fluid. One embodiment determines OBM filtrate fraction in a borehole fluid sample. One embodiment is used when there is significant difference between the coloration of formation fluid and the coloration of OBM filtrate. Another is used when there is little or no difference between the coloration of formation fluid and the coloration of OBM filtrate. Another determines GOR of formation fluid corrected for OBM filtrate contamination. Another determines OD of formation fluid corrected for OBM filtrate contamination. Another determines conditions that would render optical density measurements invalid and sample capture premature.