Abstract: An apparatus and method are described to estimate a fraction of carbon dioxide present in a downhole fluid. The apparatus includes a carrier configured to be conveyed through a borehole penetrating the earth. The apparatus also includes a pressure sensor disposed at the carrier and configured to measure an ambient pressure of the downhole fluid and an ambient temperature sensor disposed at the carrier and configured to measure a temperature of the downhole fluid. A processor of the apparatus receives the ambient pressure and the ambient temperature measurements and solves for the fraction of carbon dioxide in the downhole fluid using a correlation function with the ambient pressure and the ambient temperature as inputs to the correlation function.

Abstract: A pressure sensor and method of sensing pressure is disclosed. An fluid port is coupled to a substrate. A first microchannel within the substrate is in fluid communication with the fluid port. The first microchannel includes a first compressible fluid, a first incompressible fluid and at least one first meniscus. A second microchannel within the substrate is in fluid communication with the fluid port. The second microchannel includes a second compressible fluid, a second incompressible fluid and at least one second meniscus. A pressure of the first meniscus and/or the second meniscus is determined.

Abstract: A detector in a gas chromatograph includes a detector inlet configured to receive a chromatographic column, the chromatographic column having a column entrance and a column exit, the column exit coupled to the detector inlet, a restriction integrated within the detector, the restriction located to receive an output of the chromatographic column, at least one pressure regulated gas source provided for normal gas chromatograph operation and arranged to provide at least one gas to a location between the integrated restriction and the column exit, and a backflush controller coupled to the pressure regulated gas source, the backflush controller configured to control a pressure differential between the column exit and the column entrance such that the at least one gas backflushes the chromatographic column when a pressure at the column exit exceeds a pressure at the column entrance.

Abstract: A device for measuring the pressure of a gas mixture composed of gas components has an amperometric sensor that works on the limiting current principle, having two electrodes connected to a direct voltage that are situated on a solid electrolyte, of which one electrode is covered by a diffusion barrier, and a measuring element for measuring the limiting current flowing via electrodes as a measure for the gas pressure. For the purpose of error-free measurement of the gas pressure in a gas mixture in which the concentration of the gas components fluctuates with time, means are provided which fix the mole fraction of a gas component, drawn upon for pressure measurement, that is present upstream of the diffusion barrier at a constant 100%, at least during the pressure measuring phase.

Abstract: Disclosed is an integrated multi-measurement system for measuring physical properties including thickness, electrical resistance and differential pressure of a gas diffusion layer for a polymer electrolyte fuel cell with respect to compression. The integrated multi-measurement system simultaneously measures changes in the physical properties of the gas diffusion layer depending on pressure upon measurement of the physical properties of the gas diffusion layer of the fuel cell and also measures through-plane permeability in which a gas is passed through a sample in a direction perpendicular to the sample and in-plane permeability in which a gas is passed through a sample in a direction parallel to the sample.

Abstract: A method and apparatus are provided for maintaining pressure inside a closed chamber equal to the changing outside pressure, detecting leaks in the plumbing (i.e., air handling system) of a trace gas flux measurement system, and estimating the kinetic volume, e.g., of such a system.

Abstract: Methods and apparatuses for determining entrained and/or dissolved gas content of gas-liquid mixtures. Data generated is used to control the True (air-free) or Apparent (air-containing) Density or Entrained Air content of liquids within optimum ranges, e.g. in paper coating processes and in the manufacture of food products, personal care products, pharmaceutical products, paints, petroleum blends, etc.

Abstract: The gas absorption/adsorption memory effect in gas analysis can be reduced by controlling gas flow conditions such that the partial pressure of the analyte of interest is held constant, if the measured analyte concentration is within a predetermined range. Keeping the analyte partial pressure constant is helpful for mitigating the memory effect because changes in analyte absorption/adsorption rates tend to be driven by changes in analyte partial pressure. The memory effect can also be mitigated by performing concentration measurements at two or more different gas flow conditions, and employing a mathematical model to estimate true concentration and “memory effect” contributions to measured concentrations at one or more of the flow conditions. The mathematical model can be based on an assumption that the true analyte concentration is independent of flow rate or pressure, while the “memory effect” contribution to measured concentration is inversely proportional to flow rate or pressure.

Abstract: A combination vacuum gauge provides simultaneous absolute and differential pressure measurements over a wide range of pressures ranging from atmospheric pressures to ultrahigh vacuum by processing the readings from an absolute high vacuum gauge (e.g., an ionization gauge and/or a heat-loss sensor), a differential low vacuum gauge providing a differential relative to ambient pressure (e.g., a diaphragm sensor), and a barometric absolute pressure sensor exposed to the ambient atmosphere outside the measurement region. The barometric absolute pressure sensor reading is used to convert the differential vacuum gauge reading from uncalibrated differential pressure to calibrated absolute pressure.

Abstract: A method of measuring the density of a dielectric gas under pressure in a buried metal-clad electricity line consists in measuring the pressure and the temperature of the dielectric gas by means of a sensor mounted on the case of the line, and in compensating the pressure measurement as a function of the temperature measurement using constant density curves that have been corrected on the basis of a curve representing the difference between the temperature at the surface of the case of the line and the mean temperature of the gas inside the line for increasing amounts of current carried by the line conductor.

Abstract: Disclosed is a system and method for determining the thermodynamic properties and percentage of each component of a multi-component gas medium by using speed of sound in conjunction with other data. The present system comprises a computer system with means for obtaining the temperature, pressure, and speed of sound of a gas medium. The computer system operates according to operating logic stored in memory. According to the operating logic, measurements of the temperature, pressure, speed of sound and acoustic impedance are recorded in a gas pipe or other transport device to determine a convergent temperature range. Next a convergent series is extrapolated from the convergent temperature range and a convergent series calculation using isochoric convergence iterations is performed to obtain estimates of the thermo-physical properties of the gas medium.