Abstract: A primary chromatographic system is operated with a standard sample at several temperatures to generate primary retention times which are fitted to a function to determine thermodynamic constants to relate the times to temperature. A target chromatographic system is operated with the standard sample to generate secondary retention times. The function is used with these times to determine and an effective column parameter for the target system. The function then is used with this parameter and the primary times to determine a pressure program. Further operation of the target system with a application sample and the pressure program effects standardized retention times. A particular searching technique is utilized to apply the function. A temperature calibration technique with a selected sample measures column temperature for the target system, and a validation is done on the target system.

Abstract: In a mounting apparatus for an induction coupled plasma generator, a housing assembly has a receptacle with a central opening aligned over a housing wall opening, electrical contact rings in the receptacle, and a gas block with a central aperture aligned with the openings. An outer passage in the gas block receives a plasma forming gas and extends to the central aperture. A mounting assembly has a mounting member with an annular contact ring, a second gas block, and a gas tube and a sample tube extending from the second gas block. The second gas block has an inner passage extending into the gas tube. The mounting assembly removably engages to the housing assembly, with the mounting member on the receptacle, the second gas block in the first gas block, and the rings in contact. The tubes extend to a load coil for the plasma, and the passages align to convey the plasma forming gas into the gas tube.

Abstract: A calorimeter apparatus includes a facility for rapid cooling of a heating vessel therein. A jacket surrounds the vessel wall. A partition member between the jacket and the vessel wall defines an inlet plenum adjacent the jacket and a spatial gap adjacent the vessel wall. Pressurized cooling gas is conveyed into the inlet plenum after termination of heating the vessel. The partition member has a distributed plurality of orifices such that the gas is jetted through the orifices to impingement cool the vessel wall. The gas is discharged from the spatial gap through an outlet plenum at an end wall of the vessel. The plurality of orifices are distributed in a pattern of varying density across the partition member such that uniform cooling of the vessel wall by the jetted gas is effected.

Abstract: A connecting apparatus for conveyance of cryogenic fluid has a pair of connecting members formed of thermal insulating material. Each has a flange with an axial tubular protrusion and a rim extending over the protrusion so as to form an annular cavity therebetween. Each flange and its protrusion has a central bore. When the two members are fitted together, the combined bore conveys of cryogenic fluid therethrough. The protrusions have overlapping lips with a snug fit to substantially retain the cryogenic fluid in the combined bore. A detachable retainer holds the members in union with an o-ring seal between the rims. The respective cavities form an enclosed cavity that provides thermal insulation between the ring seal and the tubular protrusions for the cryogenic fluid in the common bore.

Abstract: A cryogenic fluid conveying device has removable connection of a metal tube and a receptor for the tube. The receptor is formed of a housing member with an aperture therein for conveying the fluid. A tubular member of resilient PTFE has a bore size so as to be slidingly receptive of the rigid tube. A ferrule is disposed on the tubular member which is positioned in the housing member. An annular nut is threaded onto an end of the housing to constrict the ferrule and thereby constrict an annular section of the tubular member. This constriction provides a sealingly tight fit for the rigid tube such that the metal tube can be inserted into and removed from the tubular member.

Abstract: In a gas chromatographic system that includes a column and an injector with a chamber, a carrier gas normally flows into the chamber at a constant rate, and a constant primary pressure is maintained at the column inlet. A sampling receptacle selectively communicates a sample vessel with a source of transfer gas or the chamber. The vessel is pressurized with the transfer gas to a starting pressure greater than the primary pressure. Analyte sample in transfer gas is then tranferred from the vessel to the chamber by the vessel pressure while the vessel pressure remains greater than the primary pressure. Carrier gas flow is discontinued during transfer, so that analyte sample transfers through the chamber into the column by the primary pressure linearly with time. Standby and venting states are provided.

Abstract: An apparatus for controlling level of cryogenic liquid in a vessel includes a transfer duct to a pressure supply tank. Pressure pulses are applied to the tank at one rate when the level is below a primary sensor in the vessel, and at a lower rate when the level is above the sensor, so as to compensate for intrinsic declination of the level. At startup a constant pressure is applied to the tank until the level reaches a lower sensor, and a relief valve over the tank is opened when the level overshoots to an upper sensor. Turbulence in the vessel is reduced by a pair of coaxial baffles at the liquid inlet to the vessel, and by a housing with tubular extensions enveloping the sensors.

Abstract: A thermally insulated calorimeter includes a vessel with a chamber containing liquid nitrogen. The vessel is formed of four walls arranged proximately in parallel, each pair of adjacent walls delimiting a space. An inner wall forms the chamber, two partition walls are between the inner wall and an outer wall which is exposed to atmosphere. Each space contains a gas at atmospheric pressure. Each spacing is selected to minimize heat transfer from the atmosphere to the inner chamber, by establishing a maximum spacing for which the air is stagnant. A cover for the vessel has a set of walls with spacings similar to those of the vessel. Sealing for such spacing is provided for a removable main cover and a removable top cover for the calorimeter sample block.

Abstract: An apparatus to provide a laminar curtain of dry gas over a cryogenic working surface includes a housing duct extending longitudinally from the working surface. A honeycomb member fills a section of the duct adjacent to the working surface, each honeycomb cell having a through channel in the longitudinal direction. A porous foam with through porosity fills a section of the duct adjacent to the honeycomb member oppositely from the working surface. A plenum is adjacent to the porous member oppositely from the honeycomb. Dry gas is supplied to the plenum to flow through the foam and honeycomb to effect the laminar curtain.

Abstract: A spectrometer includes a pair of crossed reflective gratings to effect a spectrally dispersed beam that is focussed to an array detector. The second grating is a plural grating with a surface formed of a first portion and a second portion. The first portion has a groove density for effecting ultraviolet in the dispersed beam. The second portion has a groove density for effecting visible radiation in the dispersed beam. A shutter blocks or exposes the second portion of the grating surface so as to select the first spectral range or the second spectral range for detection. The plural grating surface preferably may be contoured to compensate for aberrations in focussing of the beam to the detector. A computer may be used for selecting spectral lines for analysis, particularly selecting such lines in the second range that are not interfered with by the first range.

Abstract: A gas chromatographic system includes a column and an injector for delivering into the column a test portion of flow. The injector has an exit passage for discharging a split portion of carrier flow. A flow controller for regulating the inlet flow rate includes a variable outlet restrictor for the split portion, a flow rate detector disposed to detect inlet flow rate, and a feedback flow controller to regulate the outlet restrictor to maintain the inlet flow rate substantially constant. Pressure at the inlet to the injector is regulated by detecting pressure at an outlet and providing feedback control to an inlet restrictor. An integral module for the gas components is used on each side of the injector. Calibration and correction for gas characteristics are provided in the feedback for a chromatographic system and for other flow controller regulation.

Abstract: In a system for measuring variations in thickness of an optical etalon, a light source and a diffraction grating are mounted on a base structure with an axle. A lever arm is affixed to the axle, and a micrometer is held in contact with the lever arm. The grating directs a into an optical path a wavelength of radiation dependent on orientation of the grating. The etalon is supported in the optical path to effect a fringe pattern representing variations in thickness of in the etalon. The orientation is varied with the micrometer so as to vary the wavelength to the etalon and thereby positioning of the fringe pattern across the etalon which is viewed through a microscope. The micrometer measures the variation of orientation and thereby variation in thickness across the interference element.

Abstract: In a spectrophotometer, each of a plurality of source optical fibers is selectively receptive of source radiation and carries the radiation to a corresponding selected liquid sample cell. A corresponding return optical fiber returns transmitted radiation from the sample to a polychromator. For selecting a sample, a switching member holds exposed ends of the optical fibers on a circle coaxial with an axle for rotating to selected positions. Respective optical trains in the instrument direct radiation into and out of the selected pair of fibers. The diameter of a source aperture, the spacing of the aperture from the radiation source, and the source area define a source etendue. The optical fibers have a fiber etendue substantially the same as the source etendue.

Abstract: An atomic emission spectrometer includes an induction coupled plasma generator and a detector system for detecting the radiation relative to spectral wavelength. A first mirror is on the longitudinal axis of the generator to receive axial radiation therefrom. A second mirror is disposed laterally from the generator so as to reflect radial radiation therefrom parallel to the longitudinal axis toward a third mirror disposed laterally from the longitudinal axis. The third mirror passes the radiation to a fourth mirror positioned adjacent to the axial radiation without interfering therewith so as to reflect the radial radiation to the first mirror. The first mirror is rotated to a first orientation to reflect the axial radiation into the detector system, or to a second orientation to reflect the radial radiation into the detector system.

Abstract: An optical switch includes a primary optical fiber terminating in a primary window, and a plurality of secondary optical fibers each terminating in a secondary window facing in the same direction as and spaced laterally from the primary window. A primary lens on a primary axis has a focal point positioned on the axis at the central window. Each of a plurality of secondary lenses has an axis and a focal point positioned on such axis at a secondary window. The secondary axes are parallel to and equidistant from the primary axis. A retroreflector is spaced from the lenses oppositely from each window and has an optical axis centered parallel to the primary axis midway between the primary axis and any of the secondary fibers. A stepper motor rotates the retroreflector about the primary axis to each of a plurality of selected positions to provide optical switching for light transmission between the primary fiber and any selected secondary fiber.

Abstract: A method and apparatus are provided for correction of spectra for stray radiation in a spectrometric instrument, involving a sequence of steps as follows. Spectral patterns are obtained with the instrument initially for monochromatic radiation at a plurality of selected calibration wavelengths. By computer program, the peak profile at the calibration wavelength in each pattern is replaced with a substitute based on the remaining pattern. The resulting data are interpolated to effect values denoted "stray proportions" for the ordered wavelengths of the instrument. Spectral data at each ordered wavelength are obtained with the instrument for a sample, and multiplied in the computer program by stray proportions for corresponding wavelengths to effect further sets of values denoted "stray portions" that are identified to the ordered wavelengths. Each set is identified to one of the wavelength increments of the instrument across the spectral range.

Abstract: In a spectrophotometer, each of a plurality of source optical fibers is selectively receptive of source radiation and carries the radiation to a corresponding selected liquid sample cell. A corresponding return optical fiber returns transmitted radiation from the sample to a polychromator. For selecting a sample, a switching member holds exposed ends of the optical fibers on a circle coaxial with an axle for rotating to selected positions. Respective optical trains in the instrument direct radiation into and out of the selected pair of fibers. The diameter of a source aperture, the spacing of the aperture from the radiation source, and the source area define a source etendue. The optical fibers have a fiber etendue substantially the same as the source etendue.

Abstract: A method for determining concentration of an analyte in a sample includes generating a spectrum of a selected analyte and interferents, generating a spectrum of an unknown sample, computing first and second derivatives of the sample spectrum, deriving a matrix model that includes the analyte spectrum and the derivatives, and applying the matrix model to the sample spectrum so as to yield a parameter representing concentration of the selected analyte in the unknown sample. Multiple linear least squares regression is utilized to fit the model and calculate the parameter.

Abstract: A detector cell assembly for use in a spectrophotometer comprises a thermally insulating body having a bore with open ends therethrough and transparent windows closing the ends of the bore. An inlet passage and an outlet passage open into the bore adjacent the opposite ends thereof for flowing fluid therethrough. The body has size defined by an outer surface spaced laterally from the bore by a distance of at least about two times the bore diameter. Preferably the thermally insulating body is polymeric and has an outwardly facing annular surface respectively encircling each end of the bore approximately normal thereto and in contact with a corresponding surface on the respective window. A spring urges each respective transparent window against the respective annular surface to effect a fluid seal between the body and each window.

Abstract: A novel iron based alloy is disclosed which is characterized by high resistance to wear and corrosion. The alloy consists essentially of 0 to 40% chromium, 1 to 40% molybdenum, 1 to 15% copper, 0.2 to 5% boron, and 0.01 to 2% carbon; the balance being incidental impurities and at least 30% iron, with the molydenum being at least 10% if the boron is greater than 2%. The alloy is preferably in the form of a powder for thermal spraying, and coatings produced thereby may have an amorphous structure.