Abstract: In a magnetic resonance imaging system, an RF power amplifier is employed to boost an RF pulse to sufficient strength to excite the nuclear spins in a subject. The non-ideal behavior of the amplifier distorts the shape of an excitation pulse, and this distortion in turn degrades a slice profile. The distortion of the RF signal is manifested by nonlinearity in amplification and in incidental phase modulation. By determining the amount of nonlinearity and the phase modulation resulting from the power amplification, the baseband RF signal can be predistorted or prewarped to offset the distortion resulting from amplification. Improved slice selectivity results therefrom.

Abstract: A method for discovering amounts of halogen in a liquid is provided wherein a reservoir comprising the liquid and suspected halogen is heated to a temperature characteristic of the solubility of halogen in the liquid to provide a vapor. After condensing, a sampling vapor is provided from which the amount of halogen may be detected.

Abstract: A photoacoustic imaging method comprises the steps of using modulated light of two different modulation frequencies to illuminate an object to be observed, so that an image of only a region of a specified depth within the object is obtained based on the difference between two photoacoustic signals separately detected by an acoustic sensor.

Abstract: Especially precise and reliable measurements and evaluations are obtained by measuring one or more propagation parameters of electromagnetic waves in a wave guide or resonator at least partially filled with fuel and evaluated in an evaluating circuit as the measure for the alcohol content and/or the calorific value. According to one embodiment, the travel time or the travel time difference of an electromagnetic wave between two or more points in a wave guide filled with fuel is determined and is evaluated through computer or circuit technology as the measure for the alcohol content and/or the calorific value.

Abstract: Method of fumigating bulk cereal grains while in storage, comprising the steps of providing a closed empty compartment having internal and external walls in which compartment said cereal grain is to be stored; initially exposing the internal walls of said empty compartment and the space within said compartment to a first fumigant to disinfect the compartment; said first fumigant being providing in sufficient volume to leave a residue film deposit of fumigant on said internal walls; inspecting the external walls of said compartment to ascertain the degree of air-tightness of said empty compartment during said initial fumigation by seeking to detect leaks; repairing any leaks detected during said initial fumigation and inspection; thereafter loading said compartment with bulk cereal grain; and closing said compartment and exposing said grain to a second fumigant to disinfect said bulk cereal grain with said second fumigant as well as with said residue of said first fumigant.

Abstract: A method and apparatus for continuously monitoring the ratio of gases in a two gas mixture such as a therapeutic oxygen/nitrogen mixture. The gas mixture is passed through a sample tube within which ultrasound waves travel in successive bursts of pulses at the resonant frequency of the transmitter/receiver pair. Between bursts is a quiescent time period having a duration long enough to assure dissipation of transients so that standing waves do not form. The delay caused by the transit time of the sound through the gas sample generates electrical pulses that are translated into an analog signal which is then temperature-corrected. The resulting voltage, which is proportional to the transit time and thus to the gas composition, is compared with adjustable reference voltages to trigger high and low audio/visual alarms. A digital display provides a constant readout of the percentage of the gas component having the highest molecular weight.

Abstract: Method and apparatus for generating a precisely defined dynamic pressure pulse. A rigid pressure chamber contains a pressure transmission agent. The pressure chamber has a through opening in which is disposed a piston. A drop weight outside the pressure chamber coacts with the piston to generate a pressure pulse. The mass of the drop weight and the cross section of the piston, along with the chronological curve of acceleration of the drop weight during coaction with the piston, are used to generate a curve representing the pressure pulse. The curve satisfies the following equation: ##EQU1## wherein: m=mass of the drop weight;a(t)=said acceleration curve; andA=said cross sectional area of said piston.

Abstract: A device is disclosed for measuring the variation of the distance separating the two faces of a layer of solid material by means of ultrasounds, comprising:a generator generating a first alternating electric signal,an electroacoustic transmitting transducer,first coupling means for applying the ultrasonic wave to said layer of material,an electroacoustic receiving transducer,second coupling means for applying said ultrasonic wave to said electroacoustic receiving transducer,means for continuously measuring the variation of the phase-shift of the electric signal emitted by the receiving transducer with respect to said first alternating electric signal, andcomputing means for deriving said distance variation from said phase-shift variation, wherein:said electroacoustic transmitting and receiving transducer, as well as said first and second coupling means are disposed on the same side of said layer of material, andsaid first and second coupling means are solid ultrasonic wave-guides.

Abstract: A method for rephasing one or more of the motion components of moving material in a nuclear magnetic resonance imaging system, including velocity, acceleration, pulsatility and higher order motion components. Gradient pulses are applied in one or more of the read, phase encode and slice select directions, and subsequent gradients are then applied in one or more of such directions so that the total net phase in such direction is zero for the desired motion component and non-zero for static material.

Abstract: A tester, temporarily connectable to a tap in the input line for a gasoline dispenser, tests the integrity of the delivery line from a submerged pump within a gasoline storage tank to the tap, including a leak detector, whether piston or diaphragm operated, normally mounted at the storage tank downstream of the submerged pump. An in line isolator is installed between the submerged pump output line and the leak detector to make a field test of the integrity and operability of the leak detector.

Abstract: Contamination in the atmosphere is sensed and identified using unsealed d mode resonators and a means to clean the resonators in an ongoing method to measure contamination induced frequency change with time, while compensating for temperatures induced frequency shifts.

Abstract: A magnetic sphere or needle rheometer which may be fully controlled by a personal computer is provided. The rheometer is capable of measuring viscosities in the range of 5.times.10.sup.-4 to 5.times.10.sup.4 Pas (0.5 cP to 5.times.10.sup.7 cP). It can operate at shear rates between 1 s.sup.-1 and 2.times.10.sup.-4 s.sup.-1 and measure relaxation times down to 100 ms. The rheometer includes a magnetic coil which is used to maintain the sphere or needle in a selected position within a sample cell. The current required to maintain the sphere or needle in this position as the sample cell is moved up or down is measured. The viscosity of the liquid can be calculated from the difference in current flowing through the coil when the cell is stationary and when it is moved at a constant velocity.

Abstract: An acoustic sensor and associated electronic circuitry are used to determine when a catastrophic leak (as e.g. may be caused by a sprinkler nozzle being broken off a pipe) occurs in a sprinkling system. When a catastrophic leak is detected, an alarm signal is generated and a shutoff valve may be actuated in order to prevent loss of fluid and possible damage that can occur due to localized high flow of the fluid that is being sprayed. The acoustic sensor responds to a frequency range of acoustic signals that encompasses the generally low frequency signals generated by the relatively unconstrained flow of fluid through a pipe, as well as the higher frequency signals generated by flow of fluid through one or more nozzles. Electronic signal processing means are employed to form a ratio of the acoustic power in two different frequency regions and to generate an alarm signal when flow generates an excess of low frequency acoustic power.

Abstract: Unidirectional vibration testing apparatus under a controlled atmosphere comprising a tight enclosure (10) in which is placed a support (24) for the equipment to be tested and a vibration generator (18) positioned outside the enclosure and connected to the support by a connecting rod (22). The latter is connected to two opposite walls (10a, 10b) of the enclosure by two identical sealing systems (26, 34) mounted in opposition, so as to eliminate the parasitic or spurious effects induced by the sealing system (26), which must be placed between the rod (22) and the wall (10a) located between the vibration generator (18) and the support (24).

Abstract: A device is disclosed which allows an object to be tuned to an incoming sound wave magnitude and wavelength, such that the sound wave will alternatively be passed therethrough without detectable reflection or be completely reflected. The apparatus is intended to be mounted within a hollow object and adjust the perceived distance between the exterior walls of that object to mimic a single thick wall. A signal processing means is supplied which detects the sound wave magnitude and wavelength impinging on the wall facing the sound wave source. The wavelength is passed to the signal processing means, which transmits a complimentary signal to the second wall of the hollow object. The complimentary signal allows the hollow object to resonate as a whole as if it were a solid of a thickness much different from its actual thickness, allowing the sound wave to pass undisturbed therethrough or be reflected therefrom.