Abstract: A method of and apparatus for liquid chromatography at improved analytical and preparative speeds and quantities involves flow of fluids through the column at flow rates sufficient to induce turbulent flow in those fluids. In one embodiment, the apparatus and method includes a substantially uniform chromatography column created by packing together a multiplicity of rigid, solid, porous particles having diameters of not less than about 30 .mu.m, surfaces of the particles being chromatographically active. A fluid mixture containing at least one solute that is reactive with the particle surfaces is injected into the column and subsequently eluted therefrom by a eluant fluid flow, both the injection and elution being effected at a velocity sufficient to induce flow within at least a substantial portion of the interstitial volume between the particles at a reduced velocity greater than about 5,000.

Abstract: A scanning tomography system has a gantry including a disk for supporting a X-ray source and detector array and rotatable about a central axis. Multiple scans are made to reduce the effects of motion artifacts and improve image quality. In addition, the detector array is supported by a suspension system and is movable about the focal spot of the X-ray source a small amount so that in one mode of operation the detector array can be shifted at a predetermined angle from one position to at least one other position during a scan so as to provide an increase in the number of unique X-ray paths so as to provide improved image quality. In a second mode of operation, the detector array can be offset from the center ray so as to provide a quarter of a detector offset.

Abstract: The surface of an acoustic reflector faces the source, and has a plurality (N) of wells, where N is an odd prime number. Each well has a depth D.sub.n =(n.sup.2 rem N)* unit depth (0<=N<=N-1), governed by a Quadratic Residue Sequence. Acoustic energy directed from the source to the reflector, and reflected along a length direction of the reflector, has substantially equal acoustic energy in all angular directions from the reflector within plus and minus .pi./2 from the direction of radiation. The surface above can be used for the surface of a loudspeaker, where either it is the surface of the loudspeaker or has speakers positioned at the bottom of the wells. The surface above can also be used for drag reduction in moving vehicles when it is positioned either at the front or rear of the vehicle.

Abstract: The invention is an autozero compensator for use in processing low level signals, the compensator comprising an input integrating operational amplifier providing at its output in one mode an error signal responsively to offset voltage across the differential input terminals of the amplifier. A second amplifier is provided in a feedback loop for generating from the error signal a charge at a compensating voltage equal and opposite to the offset voltage. That charge is capacitively stored and applied to the input amplifier to cancel the offset voltage.

Abstract: In an x-ray scanning system having an x-ray source and a plurality of x-ray detectors mounted in substantially linear arrays and positioned along an arc extending about a focal spot defined by the x-ray source, the placement of the arrays along the arc is optimized to substantially avoid interfering contact between adjacent arrays. Each detector array is located at a preselected radial distance from the focal spot and oriented at a preselected angle with respect to radial lines extending from the focal spot so that the radiation-insensitive end portions of adjacent arrays overlap in the tangential direction. The tangential spacing between adjacent detector arrays is thus approximately equal to the tangential spacing between adjacent detectors in a single array.

Abstract: A ventilated garment is provided having at least one substantially non-stretchable front panel and at least one rear panel, in which the front and rear panels have an opening therein, and in which the front panel includes a substantially non-stretchable, air permeable, vent panel, having a shape substantially corresponding to the front panel opening, affixed to the front panel along the periphery of the front panel opening. The front panel further includes a cover element having a shape substantially corresponding to the front panel opening. A first portion of the cover element periphery is affixed to the front panel substantially along a first portion of the periphery of the front panel opening.

Abstract: An oxidation reactor having particular utility in a system for measuring carbon in an aqueous sample. A first chamber and second chamber are separated by a hydrogen-permeable electrode, each chamber having a separate electrolysis cell. The hydrogen-permeable electrode acts as the anode of one cell and the cathode of the other cell. The sample stream flows into one chamber and the electrolysis cell produces oxygen from the water at one optically transparent electrode and in combination with short wave ultraviolet light oxidizes organic carbon to CO.sub.2 and produces hydrogen at the other electrode which passes through the hydrogen-permeable electrode into the second chamber. The electrolysis cell in the second chamber produces oxygen at hydrogen-permeable electrode to react with the hydrogen that passes through the hydrogen-permeable electrode to form water, thereby maintaining the maximum concentration gradient of hydrogen across the hydrogen-permeable electrode to improve hydrogen transferring efficiency.

Abstract: The present invention is directed to an assembly for stretching a body cavity to a predetermined shape. The assembly includes an inelastic balloon that is affixed to the distal end of a balloon-tube. The tube defines an interior channel extending along a central axis that is contiguous with the interior of the balloon such that inflation and deflation of the balloon is controllable from the proximal end of the tube. When inflated the balloon defines a predetermined surface contour disposed about an interior region extending along a balloon axis. An alignment device operative from the proximal end of the tube provides for selectively aligning the central and balloon axes to a predetermined angular orientation.

Abstract: A computed tomography (CT) system utilizes a ring suppression filter for suppressing ring artifacts in a CT image. The system generates projections at a plurality of projection angles, and each projection includes one measurement of a plurality of projection data signals. The ring suppression filter includes a high pass filter, a histogram generator, and a combiner. The high pass filter generates a measurement of an error signal corresponding to each of the measurements of one of the projection data signals, and each of the error signal measurements is representative of the high frequency components in a portion of one of the projections. The histogram generator generates a histogram signal representative of a relationship between the measurements of the error signal and the measurements of the projection data signal. The combiner combines the measurements of the error signal and the histogram signal to generate a plurality of measurements of a ring corrected signal.

Abstract: The invention provides a system for and method of precalibrating the position of the focal spot of an X-ray tube before its installation in a CT scanner system so that the focal spot of the tube is properly aligned with the off-focal aperture, slice-defining aperture and detectors of the scanner system. The precalibration is performed using an interface registration support that receives the X-ray tube and supports the X-ray tube on a mount provided in either the precalibration system or the scanner system. The mount of the precalibration system duplicates the mount of the scanner system, so that desired position of the focal spot in the scanner system relative to the scanner system mount is duplicated in the precalibration system relative to the precalibration system mount.

Abstract: A method of testing an acoustic array antenna, consisting in using at least one independent acoustic transducer of non-directional type for receiving the same signal simultaneously via the transducer and via the antenna, and in comparing the received signals to identify possible fixed echoes and to verify whether or not the antenna and its associated cabling, relay, amplification, and signal generating and processing means are in a nominal operating state.

Abstract: A fault tolerant power supply system includes a plurality of devices coupled to a common power distribution bus. The devices are arranged and connected in a hierarchical order. The system provides that the devices of higher rank or position in the hierarchy to obtain priority in drawing power from the bus. Each device is coupled to the next adjacent device via a control status line that indicates whether there has been a failure of the power supply of any device higher up in the hierarchy. In the event that the local power supply of a device fails, it can be selectively connected to the power distribution bus to draw power, only if the control status line indicates that there have no failures in the devices having a higher hierarchical rank. Once connected to power distribution bus, if a higher ranking device should experience a power supply failure, the device will be disconnected from the power distribution bus and the higher ranking device connected to the power distribution bus.

Abstract: A port switching hub consists of a number of local area network ports, a number of internal channels to which these ports may be connected from time to time under program control, and circuitry suitable for causing each channel to function as a local area network repeater. The ports have a variety of control and measurement functions associated with them. An instrumentation, a programmable controller or embedded computer program, for example, estimates the traffic load on each channel based on information available from the port controllers. The control program further predicts the effect of reassigning the ports to different channels based on available data, internal models of network behavior, and other constraints such as address assignment, and changes the port assignment so as to achieve a goal, such as balancing of traffic load or assignment. The reassignment of ports may occur periodically, or in response to an event, and may or may not be forced to occur during a period of channel inactivity.

Abstract: The disclosed ultrasound system processes ultrasound signals having centroid frequencies that decrease as a function of time. The system includes transducers for receiving the ultrasound signals and generating electrical signals representative thereof. The system further includes data samplers for sampling the electrical signals with a sampling frequency. A controller controls the sampling frequency so that it decreases according to a function of time and the centroid frequency.

Abstract: A method and apparatus are disclosed for regenerating and/or stabilizing the activity of a dehydrogenation catalyst used in dehydrogenating an alkylaromatic hydrocarbon to obtain an alkenylaromatic hydrocarbon, the method comprising the steps of continuously or intermittently adding to a reactant stream an effective amount of an alkali metal or alkali metal compound without interrupting the dehydrogenation reaction.

Abstract: A current sensor for detecting AC current through a load impedance of an electrical circuit. Sensor components are fabricated within a multilayer board so that a board can be made to comprise a plurality of independent sensors. The sensor includes a transformer circuit including a primary coil which is electrically coupled in series with the current path of the electrical circuit. This primary coil includes at least one current path element, in the form of a conductive strip constructed so as to add minimal resistance and inductance to the electrical circuit. The transformer secondary comprises at least a first electrically conductive coil inductively coupled to at least a part of the current path, and preferably a second electrically conductive coil inductively coupled to a second part of current path of the electrical circuit.

Abstract: A vapor compression system with set point optimization generates a set of thermodynamic operating parameters such that the system operates with optimum energy efficiency. Based on environmental conditions such as indoor and outdoor temperature as well as thermal load, the set of parameters for steady-state set point is generated. The system also monitors actual system properties in real-time and provides them as feedback to the set point computation module. Based on these actual real-time measurements, a new steady-state set point can be generated to enable the system to continue operating at maximum coefficient of performance upon change in environmental or thermal load requirements.

Abstract: The invention is an autozeroing circuit for use in processing low level electrical charge signals by an integrating operational amplifier. The autozeroing circuit includes a switching circuit that periodically charges and discharges the integrating capacitor of the amplifier during set and reset phases of an operation cycle so that during the set phase of the cycle the input signal is integrated and processed by processing circuitry including an A/D converter, and during the reset phase the integrator is cleared.

Abstract: An impeller for a radial flow device selected from the group consisting of radial--and mixed-flow compressors, pumps and turbines which is designed for both aerodynamic performance and manufacturability at high production rates. The mean blade surface of the impeller is substantially helical, as the angle of any point on the mean blade surface relative to a meridional plane passing through the axis of rotation of the impeller varies linearly with the radius and z-axis location of that point relative to an arbitrary radial plane z.sub.0. A single-piece mold for making the impeller, and a method for making the mold, are also disclosed. The impeller can made in a high-speed molding process without significant post-production processing, and it can be easily withdrawn from a mold without destruction or disassembly of the mold.

Abstract: parallel interface is provided between a standard parallel port of a computer system and a modem so as to increase the data transfer rate between the two systems without modifying the hardware of the computer system and independently of the application program running on the computer system.