Abstract: A fiber optic switch interconnects fiber optic channels so that a fiber optic network can be implemented. Channel modules provide ports (p1-pi) for connection of the fiber optic channels. Each channel module has a receive memory for temporarily storing incoming data frames from the fiber optic channels associated therewith. A switch module having a data distribution network interconnects each of the channel modules and permits ultimate connection of a source channel to a destination channel. A path allocation system, which controls the switch module, allocates the data paths between the channels. The path allocation system has a scheduler which maintains a destination queue (Q.sub.p1 -Q.sub.pi) for each of the channels, a sentry which determines when a new data frame is ready to be routed, and an arbitrator which arbitrates port availability and which grants transfer requests proposed by the scheduler.

Abstract: In the preferred embodiment, the invention is embodied in the pneumatic manifold of a gas chromatograph to provide current operating temperature and pressure compensation of inlet fluid flow. The pneumatic manifold comprises a plurality of thermally coupled mass flow, pressure and temperature sensors which generate signals related to mass flow of the fluid, fluid pressure and sensor temperature prior to the introduction of the fluid into the column. A plurality of firmware models which characterize the effects of current operating temperature and pressure variations on the mass flow and pressure sensors are stored in computer memory.

Abstract: The invention provides for increased IC density on circuit boards having at least one IC mounted on each side of a two sided PC or SMT board by utilizing one or more IC's having pin assignments arranged as a mirror image of each other along a centerline through the IC package in the X or Y axis, such that one or more IC's having the same set of mirror image pin assignments mounted on each side of a circuit board and rotated 180 degrees in relationship to each other will ensure that the pin assignments of the same type will be directly opposite each other and separated by the circuit board.

Abstract: A fiber optic switch interconnects ports (p1-pi) for connection with respective fiber optic channels so that a fiber optic network is realized. Channel modules provide the ports. Each channel module has a port intelligence mechanism for each port and a memory interface system for temporarily storing data passing to and from the ports. A switch module having a main distribution network, an intermix distribution network, and a control distribution network interconnects the memory interface systems and permits exchange of data among the ports and memory interface systems. A path allocation system controls the switch module and allocates the data paths therethrough. The path allocation system has a scheduler which maintains a destination queue (Q.sub.p1 -Q.sub.pi) for each of the ports. The destination queues are implemented with a double link list in a single memory configuration so that a separate queue structure in hardware is not necessary.

Abstract: A cap for sealing pressure vessels is disclosed. The present invention permits a nominal closure to be formed by hand tightening and a substantially higher force to be applied to a cap by a separate clamp mechanism, thereby forming a pressure seal. In certain preferred embodiments, means for providing a process flow through a hole in the seal and filtering means are also provided as part of the cap assembly. A preferred application of the cap of the present invention is for the sealing of sample vessels used for supercritical fluid extraction of compounds from a solid matrix for subsequent chemical analysis. Methods of supercritical fluid extraction are also disclosed. The present invention thus provides methods and apparatus whereby the placement of a sample into a pressurized system may be automated and monitored to ensure adequate seals have been created and maintained within such pressurized systems.

Abstract: A method for sample preparation in which a sample matrix is formed into a thin film prior to being brought into contact with an extraction solvent such that the surface area contact between the sample matrix and the solvent is maximized and the cross section of the sample matrix and corresponding diffusion path of components of interest is minimized.

Abstract: Analog-to-Digital Converter (A/D converter) consisting of several continuously integrating charge balancing (CB) conversion stages. During each conversion interval, all CB capacitors are discharged by a reference current. In each stage, the end of the discharge of the CB capacitor is detected by a zero crossing detector. Time intervals between the zero crossing events and corresponding discharge termination events represent time equivalents of quantization errors. Each stage, other than the first, converts the time equivalents of quantization errors of the previous stage. Output of the entire multistage A/D converter is combined from the outputs of all stages in a way which provides compensation of a quantization error of any stage by the output of the next stage. Quantization noise (sequence of quantization errors) of the entire A/D converter becomes the same as the N-time differenced (N-number of stages) quantization noise of the last stage.

Abstract: The invention is a method for modifying a known chromatographic method without changing peak elution order and with little or no change in resolution. Column and operational parameters of a known method are systematically translated to ensure that a new chromatographic method having possibly different column and operational parameters has a chromatographic output with similar separation.

Abstract: Methods of separating and classifying the relative amounts of two or more classes of hydrocarbon molecules in a sample are disclosed wherein an input stream comprising a mobile phase and the sample is injected into a chromatographic column, and an effluent stream exiting a chromatographic column is split into a first effluent stream and a second effluent stream. The mass of carbon in each of the classes of hydrocarbons in the first effluent stream is determined, preferably using a flame ionization detector, and the second effluent stream is directed through a variable restrictor, allowing the pressure and mass flow rate of the input stream to be independently controlled and improved results obtained. In a preferred embodiment the present invention also includes identifying the hydrocarbon molecules in the second effluent stream in order to verify the analysis or provide additional data, preferably by using an ultraviolet detector.

Abstract: Methods of programming mechanical manipulators are disclosed that permit a mechanical manipulator to be programmed to perform coordinated motions between one or more modules comprised of equipment with which the manipulator will interact by defining an origin point and one or more frame points related to each of the modules relative to the origin point. Each of the modules associated with a frame point is then identified and a module program describing pre-programmed manipulator motions related to each of the modules is accessed. Finally, a sequence of motions between the origin and each of the frame points of the modules is defined. The step of locating frame points can be carried out in several different ways, using a teach pendant or by automatically locating the module frame points using an infrared sensor, electric field sensor, acoustic sensor, or force sensor.

Abstract: A method and device are disclosed for performing supercritical fluid chromatography in packed columns of at least about 0.5 mm inside diameter. The column provides at least 50,000, preferably at least 100,000, theoretical plates with pressure drop across the column of at least 25 bar. The outlet pressure is controlled by the back pressure regulator. The column may comprise a plurality of individual columns in series. Separation is performed at a rate of at least 25 plates/min, preferably at least 100 plates/min.

Abstract: A method and device are disclosed for performing supercritical fluid chromatography in packed columns of at least about 0.5 mm inside diameter. The column provides at least 50,000, preferably at least 100,000, theoretical plates with pressure drop across the column of at least 25 bar. The outlet pressure is controlled by the back pressure regulator. The column may comprise a plurality of individual columns in series. Separation is performed at a rate of at least 25 plates/min, preferably at least 100 plates/min.

Abstract: A pre-injection sample sequencing subsystem for laboratory apparatus which includes a chromatograph with a column includes a circular tray with a plurality of concentric arrays of physical locations for storing sample vials in radially extending linear arrays, and a plurality of virtual locations that are extensions of the linear arrays. Each of the physical and virtual locations are individually addressable by a controller for a robot on the tray such that pre-injection sample processing modules may be attached to the tray, located at one or more of the virtual locations. A sequencing method optimizes transfer of samples contained in the vials between their respective physical storage location and the pre-injection processing modules.

Abstract: Methods for handling a plurality of sample containers to be processed by an instrument are disclosed. In a preferred embodiment, a retaining device holds the sample containers and is indexed to align one of the sample containers to a position where communication with a sample input port of the instrument is established. A stripper moves a sample container into engagement with the sample port and, most preferably, also urges the sample container into sealing engagement with the sample port. An interference fit created between the stripper an the sample container provides a positive force that permits the sample container to be withdrawn and returned to its initial position. A lower arm assembly is disclosed which acts as a stop relative to the sample container and thus, as the stripper continues to move while the sample container is being withdrawn it overcomes the force of the interference fit and disengages the stripper.

Abstract: Methods and apparatus for exchanging the end effectors of apparatus for handling objects, such as robotic manipulators are disclosed. A compliant tool depository is used in conjunction with a tool holder to perform the end effector exchange. The present invention utilizes the motive force provided by the end effector actuation to execute the sequence required for end effector exchange. A bi-stable latch is provided which minimizes the force required to latch and unlatch the end effectors, thereby providing an end effector exchange mechanism useful in small laboratory robots possessing small operating forces. The tool depository design also adds to the positional forgiveness of the apparatus, allowing the robotic arm and the depository to be aligned with a lesser degree of precision than might otherwise be required.

Abstract: A scannable flip-flop circuit allows data at its data input or its scan input to be stored in the flip-flop at its data output or shifted out of the flip-flop at its scan output. The flip-flop provides control circuitry for selecting the source of the input data and scan data. Data stored at the flip-flop data output may also be shifted out at the scan output. During scan operations, additional control circuitry allows data stored at the data outputs to be preserved.

Abstract: Method and apparatus for regulating the passage of fluid through a chamber or other type of conduit. Fluid passage is terminated when the volume of fluid which has swept through a chamber equals a selected multiple of the chamber's internal volume, which multiple is known as swept chamber volumes.

Abstract: Methods of calibrating robotic manipulators are disclosed. The present invention uses an inclinometer or a leveling device to provide a reference to calibrate each encoder for each joint of a robotic manipulator. The inclinometer or leveling device is most preferably an electronic protractor or similar device that is placed on a surface of one of the links and the joint is moved until the link is at a preselected angle. In certain embodiments an offset position between the level position and an index position for an absolute encoder is determined and absolute encoder data describing the offset position is recorded. Preferably, the inclinometer is capable of generating a signal that indicates the angle of the surface of the link with respect to the gravity vector. This signal can be used to control the joints and automatically calibrate the manipulator.

Abstract: Methods and apparatus for extracting sample components from complex matrices using supercritical fluid as the principal extracting solvent are disclosed. The invention takes advantage of the fact that the solvent power of a supercritical fluid is stepwise settable by the parameters of density, modifier concentration, and temperature. Accordingly, methods and apparatus for extracting a component from a sample using fluid flow system having a variable and controllable flow restriction are disclosed. The methods of the present invention comprise the steps of inserting the sample into the sample container section, inputting temperature, pressure, flow rate and extraction time set points. Flow rate is controlled and system pressure regulated by the variable flow restriction. The output stream from the extraction is then expanded through a nozzle and into a trap. In certain embodiments, the trap is filled with chemically active packing material.

Abstract: A method and apparatus for selectively invalidating tag data related to data stored in high speed processor cache memory systems. The tag data to be invalidated, due to processor operations and cache memory misses, is stored in two tag stores and indicia related to the tag data to be invalidated is stored in a purge queue. Further improvement in system performance is provided by selective tag data and indicia elimination.