Abstract: Chromatography column assembly of the direct heating type, comprising at least a capillary column, at least a tubular structure which envelops the capillary column and is coaxial with it, means to directly heat the column, means to detect the temperature of the column and one or more electrically insulating covering elements, wherein the tubular structure comprises a plurality of tubular meshes each formed of a plurality of filaments woven together (FIG. 3).

Abstract: Transducer assemblies and methods of replacing having a housing, a removable diaphragm, and a sealing diaphragm. The transducer assembly may be used with a spool piece to prevent fluid from escaping from the spool piece when parts of the transducer assembly are removed.

Abstract: The invention relates to a device (2) for separating magnetic particles comprising several substantially aligned magnets (3). Some of the magnets (3) are inversely oriented. This array reduces any magnetic interference with the collection area of an adjacent magnet.

Abstract: A polarisation fluorometer and a method for calibrating such a fluorometer. The fluorometer includes an excitation channel with an excitation polariser for generating light polarised in a first plane or in a second plane to be conducted as a excitation light to a sample, an emission channel for conducting emission light from the sample, in which emission channel there is an emission polarisation filter, an excitation detector, to which light polarised by the excitation polariser can be conducted from the excitation channel, and a reference detector, to which light polarised by the excitation polariser can be conducted from the excitation channel before being conducted to the sample or to the excitation detector. The reference detector can be calibrated by the excitation detector so that correction measurements can be carried out in real time during sample measurement. The fluorometer can be used especially for fluorescence spectra measurements.

Abstract: Spectra obtained from spectrographic readings from a sample can be filtered for artifacts, e.g., distorted data points arising from cosmic ray interference, by subtracting one spectrum from another to obtain a difference spectrum; smoothing the difference spectrum; and then calculating the difference between the smoothed and unsmoothed difference spectra to obtain a noise spectrum. The resulting noise spectrum, which represents localized differences between the original spectra, can then be reviewed for readings which exceed the norm by some predetermined amount (e.g., readings which exceed the average level of the noise spectrum by some percentage). These excessive readings constitute distorted data points, and the corresponding points on the spectra can have their values adjusted to eliminate the excessive readings, thereby removing the artifacts.

Abstract: A method for determining a velocity of a flowing fluid includes estimating a Reynolds number for the flowing fluid; comparing the estimated Reynolds number with a selected range; and determining the velocity of the flowing fluid based on a flow model selected from a laminar flow model, a turbulent flow model, and a partial laminar flow model. An ultrasonic flow meter includes a plurality pairs of transducers configured to form a plurality of measurement paths in a pipe, wherein the plurality of measurement paths are arranged asymmetrically relative to a centerline of the pipe.

Abstract: The invention relates to a method and a device for the measurement of ions by coupling different measurement methods/techniques, a first detector being a collector (17) and a second detector being an SEM (18), and the ions to be measured or resulting secondary particles being selectively delivered to the collector or the SEM. The SEM (18) is operated selectively in analog mode or count mode. The collector (17) is provided with an integrator.

Abstract: A parallel-plate diffusion gas dehumidifier has a treatment zone having at least one water-permeable membrane. The gas dehumidifier includes an untreated gas inlet, a treatment zone bounded by water-permeable membranes, a support structure for the membranes, access to a source of vacuum, and a dehumidified gas outlet. The cross section of the treatment zone may be provided in various shapes, for example, rectangular. The gas dehumidifier inlet and outlet include flow transitions that minimize the obstruction of particles passing through the dehumidifier. The dehumidifier may be used in particle sampling systems to dehumidify the sample gas prior to introducing the sample gas to a mass measuring device and mass flow controller. Methods of operating the gas dehumidifier and the particle sampling system are also provided.

Abstract: A particulate mass monitor includes a controller that monitors a change in a resonant oscillation frequency of a taut metallic membrane, as caused by deposition of the particulate matter on the metallic membrane. The metallic membrane, such as a foil or metallized plastic film, is substantially mechanically stable under tension. Application of a tension to the periphery of the metallic membrane generates a substantially constant tension within the membrane, thereby allowing the particulate mass monitor to detect a particulate mass concentration of the air sample with a relatively high degree of accuracy. Additionally, the particulate mass monitor includes a membrane transporter that automatically advances the metallic membrane within the particulate mass monitor. The membrane transporter minimizes the necessity for manual replacement of the metallic membrane over time and allowing long term, unattended operation of the particulate mass monitor.

Abstract: A method for determining atomic isotope masses in mass spectrometry, atomic isotope ratios being determined from molecular isotope ratios measured by means of an isotope mass spectrometer—ion correction, the determination of the atomic ratios being carried out by setting up and solving a system of equations which describes relationships between the atomic and the molecular ratios, and the system of equations having to have at least as many independent equations as there are atomic ratios. The entire system of equations is linearized by means of suitable numerical methods in a first step, in particular by means of a Taylor expansion or similar method, and in which the linearized system of equations is subsequently solved as a whole without transforming the individual equations.

Abstract: A rheometer has a measuring shaft which is borne for rotation about and/or axial displacement along its longitudinal axis and has a detection device for determination of the normal force and/or the torque which acts on the measuring shaft during a measurement. The detection device thereby has a first holding member which is connected to the measuring shaft and a second holding member which is mounted to a stationary frame, wherein the second holding member is connected to the first holding member by means of resilient connecting members and at least one strain gage is introduced onto at least one of the connecting members to measure the deformation of the connecting member.

Abstract: The invention relates to a device for positioning and holding one or more chromatographic column lengths being subjected to one or more jets of fluid to change the temperature, especially in a modulator for GC×GC. The device comprises one or more V-shaped seats in which the column is housed, and pushed within the groove.

Abstract: A test body clamping device in a rheometer comprises two clamping jaws between which a test body can be clamped, and an operating device for moving the clamping jaws towards and away from each other. The invention provides that each clamping jaw is pivotably disposed about an axis, wherein the axes extend parallel to each other and parallel to a clamping surface of the respective clamping jaw. The clamping jaws moreover have an associated common drive part for exerting a drive force onto both clamping jaws, which produces a synchronized pivoting motion of both clamping jaws, wherein the clamping jaws are subjected, in their clamped position, to the action of a common clamping force element, in particular a clamping spring.

Abstract: A test circuit employs use of first and second switches to operably charge a capacitor to over 500 volts and, thereafter, discharge energy stored in the capacitor to test an over-voltage protection circuit associated with a pin of a semiconductor device. When switched by a controller, the first switch couples a high voltage source to charge a capacitor. After completing this charge phase, the controller opens the first switch, decoupling the high voltage source from the capacitor. The controller then activates the second switch to couple the capacitor to the pin of the semiconductor device. During this discharge phase, energy in the capacitor discharges through the protection circuit of the semiconductor device. Use of a high-voltage dry reed vacuum relay as the first switch provides better isolation of the high voltage source from the capacitor, avoiding a presence of an unwanted residual voltage component in a simulated ESD test pulse.

Abstract: An infrared spectrometer includes an infrared source system that is stabilized to provide a substantially constant output light intensity. The infrared source system includes a source element adapted to receive electrical power and to emit light at an intensity related to the electrical power received by the source element. A light detector is mounted in position to receive light emitted from the source element and to provide an output signal related to the intensity of the light received by the detector. A feedback control loop receives the signal from the detector and provides electrical power to the source element to maintain the intensity of the light output from the source element at a selected level as detected by the detector.

Abstract: A clip is used with a pilaster assembly, where the clip is snap-fit into the slots of the pilaster, so that the clip is retained when inserted into the slots. This provides the advantage that the clips tend not to fall out due to bumps or vibrations such as those that can occur, for example, during transport of a cabinet having the pilasters and clips.

Abstract: A method for detecting substances or mixtures of substances within a sample in an apparatus for comprehensive two-dimensional gas-chromatographic analysis according to the present invention, comprising the steps of: subjecting the sample to a first separation within a first capillary column; modulating in time the effluents from the first column by means of the subdivision into adjacent fractions of the effluents from the first column and subsequently sending each fraction into a second capillary column, the modulation of the effluents being periodic with a first modulation frequency f1 of the sample; separating each of the fractions in the aforesaid second capillary column; and detecting, at the end of the second capillary column, the effluents by means of periodic sampling by discrete time points at a second frequency f2.

Abstract: A pipette includes a housing defining a suction chamber. A piston is configured to move in the suction chamber. A first retainer mechanism includes a first threading configured to limit a motion of the piston in the suction chamber. A second retainer mechanism includes a second threading configured to limit the motion of the piston in the suction chamber, the second threading having a pitch less than a pitch of the first threading.

Abstract: A cuvette package for loading multicell cuvettes from the package into measurement instruments having their cuvette loading accessories designed to accept known packages. On top of a row of multicell cuvettes is attached a detachable bonding strip having a width smaller than that of the width of the row of multicell cuvettes. The bonding strip serving to keep the row of cuvettes together during transport and being easily detachable when the cuvettes are being loaded into the instrument. The multicell cuvettes are loaded into the instrument from the dispensing device which supports the cuvette in place and has its top surface provided with an opening permitting the removal of the strip by pulling off from the supported multicell cuvette package.