Patents by Inventor David D. Nelson
David D. Nelson has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 12339220Abstract: In various embodiments, rapid, sensitive detection of molecular hydrogen is achieved by in a detector that divides sample gas into two flows by dividing the sample gas before dampening variation and converting hydrogen to water vapor at two different points. For example, a detector may receive sample gas that includes ambient water vapor and hydrogen, divide the sample gas into a chemical conversion flow and bypass flow, perform a first chemical conversion of hydrogen in the chemical conversion flow to water vapor, alternate between drying the converted chemical conversion flow or the bypass flow to produce a modulated flow, perform a second chemical conversion of hydrogen in the modulated flow to water vapor, measure water vapor in the converted modulated flow to produce a water vapor signal, separate the water vapor signal in the time domain to extract a hydrogen-derived water vapor signal, and output a hydrogen signal based thereon.Type: GrantFiled: January 20, 2023Date of Patent: June 24, 2025Assignee: Aerodyne Research, Inc.Inventors: David D. Nelson, Jr., Scott C. Herndon, Joanne H. Shorter, Joseph R. Roscioli
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Patent number: 12292428Abstract: In various embodiments, rapid, sensitive detection of molecular hydrogen is achieved by chemically converting hydrogen to water vapor and then detecting the water vapor as a surrogate for the hydrogen. Detection may be enhanced by dampening variation in ambient water vapor and rapidly actively modulating a hydrogen-derived water vapor component. For example, the detector may receive sample gas that includes ambient water vapor and hydrogen, dry the sample gas to dampen variation in the ambient water vapor, divide the sample gas into a chemical conversion flow and a bypass flow, chemically convert hydrogen in the chemical conversion flow to water vapor, alternate between measuring water vapor in the converted chemical conversion flow or the bypass flow to produce a water vapor signal, separate the water vapor signal in the time domain to extract a hydrogen-derived water vapor signal, and output a hydrogen signal based on the hydrogen-derived water vapor signal.Type: GrantFiled: December 14, 2022Date of Patent: May 6, 2025Assignee: Aerodyne Research, Inc.Inventors: David D. Nelson, Jr., Scott C. Herndon, Joanne H. Shorter, Joseph R. Roscioli
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Publication number: 20240094178Abstract: In various embodiments, both very high speed and very high sensitivity hydrogen detection is achieved by controlling water vapor concentration over the catalyst used to convert hydrogen in sample gas (e.g., ambient air) to water vapor, to provide a substantially stable water vapor mixing level at a target mixing ratio. The naturally-occurring water vapor in the sample gas, without further steps, typically would vary over time within a wide range (e.g., due to changing atmospheric conditions). By controlling a level of water vapor over the catalyst to be substantially equal to a target mixing ratio that is not too low as to impair response time, and not too high as to impair sensitivity, both very high speed and very high sensitivity can be provided.Type: ApplicationFiled: December 1, 2023Publication date: March 21, 2024Inventors: David D. Nelson, JR., Scott C. Herndon, Joanne H. Shorter, Joseph R. Roscioli, Elizabeth M. Lunny, Richard A. Wehr
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Patent number: 11802858Abstract: In various embodiments, rapid, sensitive detection of molecular hydrogen is achieved by receiving sample gas that includes ambient water vapor and hydrogen, passing the sample gas through a gas dryer, chemically converting hydrogen in the sample gas to water vapor to produce converted sample gas, measuring water vapor in the converted sample gas to produce a water vapor signal, separating the water vapor signal in the time domain into an ambient water vapor signal and a hydrogen-derived water vapor signal, wherein the gas dryer dampens variation in the ambient water vapor signal, and outputting a hydrogen signal that describes molecular hydrogen in the sample gas that is based on the hydrogen-derived water vapor signal.Type: GrantFiled: February 18, 2021Date of Patent: October 31, 2023Assignee: Aerodyne Research, Inc.Inventors: David D. Nelson, Jr., Scott C. Herndon, Joanne H. Shorter, Joseph R. Roscioli
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Publication number: 20230152220Abstract: In various embodiments, rapid, sensitive detection of molecular hydrogen is achieved by in a detector that divides sample gas into two flows by dividing the sample gas before dampening variation and converting hydrogen to water vapor at two different points. For example, a detector may receive sample gas that includes ambient water vapor and hydrogen, divide the sample gas into a chemical conversion flow and bypass flow, perform a first chemical conversion of hydrogen in the chemical conversion flow to water vapor, alternate between drying the converted chemical conversion flow or the bypass flow to produce a modulated flow, perform a second chemical conversion of hydrogen in the modulated flow to water vapor, measure water vapor in the converted modulated flow to produce a water vapor signal, separate the water vapor signal in the time domain to extract a hydrogen-derived water vapor signal, and output a hydrogen signal based thereon.Type: ApplicationFiled: January 20, 2023Publication date: May 18, 2023Inventors: David D. Nelson, JR., Scott C. Herndon, Joanne H. Shorter, Joseph R. Roscioli
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Publication number: 20230116043Abstract: In various embodiments, rapid, sensitive detection of molecular hydrogen is achieved by chemically converting hydrogen to water vapor and then detecting the water vapor as a surrogate for the hydrogen. Detection may be enhanced by dampening variation in ambient water vapor and rapidly actively modulating a hydrogen-derived water vapor component. For example, the detector may receive sample gas that includes ambient water vapor and hydrogen, dry the sample gas to dampen variation in the ambient water vapor, divide the sample gas into a chemical conversion flow and a bypass flow, chemically convert hydrogen in the chemical conversion flow to water vapor, alternate between measuring water vapor in the converted chemical conversion flow or the bypass flow to produce a water vapor signal, separate the water vapor signal in the time domain to extract a hydrogen-derived water vapor signal, and output a hydrogen signal based on the hydrogen-derived water vapor signal.Type: ApplicationFiled: December 14, 2022Publication date: April 13, 2023Inventors: David D. Nelson, JR., Scott C. Herndon, Joanne H. Shorter, Joseph R. Roscioli
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Publication number: 20220260537Abstract: In various embodiments, rapid, sensitive detection of molecular hydrogen is achieved by receiving sample gas that includes ambient water vapor and hydrogen, passing the sample gas through a gas dryer, chemically converting hydrogen in the sample gas to water vapor to produce converted sample gas, measuring water vapor in the converted sample gas to produce a water vapor signal, separating the water vapor signal in the time domain into an ambient water vapor signal and a hydrogen-derived water vapor signal, wherein the gas dryer dampens variation in the ambient water vapor signal, and outputting a hydrogen signal that describes molecular hydrogen in the sample gas that is based on the hydrogen-derived water vapor signal.Type: ApplicationFiled: February 18, 2021Publication date: August 18, 2022Inventors: David D. Nelson, JR., Scott C. Herndon, Joanne H. Shorter, Joseph R. Roscioli
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Patent number: 9857267Abstract: In one embodiment, a CO2 leak detection instrument detects leaks from a site (e.g., a CO2 sequestration facility) using rapid concentration measurements of CO2, O2 and optionally water concentration that are achieved, for example, using laser spectroscopy (e.g. direct absorption laser spectroscopy). Water vapor in the sample gas may not be removed, or only partially removed. The sample gas may be collected using a multiplexed inlet assembly from a plurality of locations. CO2 and O2 concentrations may be corrected based on the water concentration. A resulting dataset of the CO2 and O2 concentrations is analyzed over time intervals to detect any changes in CO2 concentration that are not anti-correlated with O2 concentration, and to identify a potential CO2 leak in response thereto. The analysis may include determining eddy covariance flux measurements of sub-surface potential carbon.Type: GrantFiled: November 14, 2016Date of Patent: January 2, 2018Assignee: Aerodyne Research, Inc.Inventors: David D. Nelson, Jr., Scott C. Herndon
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Patent number: 9523666Abstract: In one embodiment, active (continuous or intermittent) passivation may be employed to prevent interaction of sticky molecules with interfaces inside of an instrument (e.g., an infrared absorption spectrometer) and thereby improve response time. A passivation species may be continuously or intermittently applied to an inlet of the instrument while a sample gas stream is being applied. The passivation species may have a highly polar functional group that strongly binds to either water or polar groups of the interfaces, and once bound presents a non-polar group to the gas phase in order to prevent further binding of polar molecules. The instrument may be actively used to detect the sticky molecules while the passivation species is being applied.Type: GrantFiled: December 15, 2014Date of Patent: December 20, 2016Assignee: Aerodyne Research, Inc.Inventors: Joseph R. Roscioli, Scott C. Herndon, David D. Nelson, Jr.
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Publication number: 20160169852Abstract: In one embodiment, active (continuous or intermittent) passivation may be employed to prevent interaction of sticky molecules with interfaces inside of an instrument (e.g., an infrared absorption spectrometer) and thereby improve response time. A passivation species may be continuously or intermittently applied to an inlet of the instrument while a sample gas stream is being applied. The passivation species may have a highly polar functional group that strongly binds to either water or polar groups of the interfaces, and once bound presents a non-polar group to the gas phase in order to prevent further binding of polar molecules. The instrument may be actively used to detect the sticky molecules while the passivation species is being applied.Type: ApplicationFiled: December 15, 2014Publication date: June 16, 2016Inventors: Joseph R. Roscioli, Scott C. Herndon, David D. Nelson, JR.
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Patent number: 9261457Abstract: In one embodiment, an apparent equilibrium constant involving a clumped isotope in a gaseous sample is measured by acquiring sample spectra of portions of the gaseous sample at different pressures. An external bulb coupled to a sample cell is filled with the gaseous sample. A first portion of the gaseous sample is transferred from the external bulb to the sample cell, where it is at a first pressure. A first sample spectrum is obtained. Then, a second portion of the gaseous sample is transferred from the external bulb to the sample cell, where it is at a second, different pressure. A second sample spectrum is obtained. An apparent equilibrium constant for the clumped isotope is calculated by determining a first isotopic ratio at the first pressure, determining a second isotopic ratio at the second pressure, and taking a product of the first isotopic ratio and the second isotopic ratio.Type: GrantFiled: November 11, 2014Date of Patent: February 16, 2016Assignee: Aerodyne Research, Inc.Inventor: David D. Nelson, Jr.
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Publication number: 20100070265Abstract: An apparatus, system, and method are disclosed for automatically displaying regulations in a first language from a search in a second language under the invention, a regulation storage module is configured to store a regulation of a country and associated information in a first language in a database. A regulation search module is configured to search in a second language information in the database regarding a regulation in the first language. A display module is configured to display the regulation identified by the regulation search module.Type: ApplicationFiled: November 19, 2009Publication date: March 18, 2010Inventors: David D. Nelson, Richard B. Nordgren
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Publication number: 20040243391Abstract: An apparatus, system, and method are disclosed for automatically displaying regulations in a first language from a search in a second language under the invention, a regulation storage module is configured to store a regulation of a country and associated information in a first language in a database. A regulation search module is configured to search in a second language information in the database regarding a regulation in the first language. A display module is configured to display the regulation identified by the regulation search module.Type: ApplicationFiled: May 27, 2004Publication date: December 2, 2004Inventors: David D. Nelson, Richard B. Nordgren, Brandon J. Campbell
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Patent number: 5877862Abstract: A cross-road motor vehicle exhaust gas analyzer uses tunable infrared laser differential absorption spectroscopy incorporating photon infrared detection to determine the absolute fractional absorption of a laser by the gaseous medium. Spectroscopic constants of the gaseous species of interest are applied to the absolute fractional absorption to calculate the pertinent absolute column densities. In addition to a laser that sweeps across one or more absorption line of an component of interest, the system of the invention includes a laser source tunable over an absorption line of a reference species; the calculated column density of the reference species is used to normalize the concentration of the component of interest to the fuel consumption rate of the motor vehicle.Type: GrantFiled: August 26, 1997Date of Patent: March 2, 1999Assignee: Aerodyne Research, Inc.Inventors: David D. Nelson, J. Barry McManus, Mark Zahniser, Charles E. Kolb