摘要:
The present invention includes a three-dimensional base body (40) having a curved surface allowing definition of a circular orbital band (B), an electroacoustic transducer (21) arranged on the orbital band (B) of the three-dimensional base body (40) and configured to excite surface acoustic wave to perform multiple roundtrips along the orbital band (B), and a sensitive film (25) formed on at least a part of the orbital band (B) of the three-dimensional base body (40) and configured to react with a specific gas molecule. The surface acoustic wave experienced the multiple roundtrips along the orbital band (B) is then converted into a high frequency electric signal again by an interdigital transducer (21). The resulting high frequency electric signal is transferred to a detection/output unit (24) via a switching unit (23) and then detected by the detection/output unit (24).
摘要:
An optoacoustic sensor for detecting one or more target gases includes a body featuring halves containing measurement cells. Each measurement cell is in communication with a light source and a microphone as well as the ambient atmosphere. Evaluation and control electronics are in communication with the light sources and the microphones sequentially illuminate the first and second light sources so that a measurement signal due to optoacoustic pressure variations from a target gas is generated by the microphone of the illuminated or gas active cell and a compensation signal is generated by the microphone of the non-illuminated or gas inactive cell. The compensation signal is subtracted from the measurement signal by the evaluation and control electronics to provide a sensor output signal.
摘要:
A method of indirectly measuring the diluent (nitrogen and carbon dioxide) concentrations in a natural gas mixture. The molecular weight of the gas is modeled as a function of the speed of sound in the gas, the diluent concentrations in the gas, and constant values, resulting in a model equation. A set of reference gas mixtures with known molecular weights and diluent concentrations is used to calculate the constant values. For the gas in question, if the speed of sound in the gas is measured at three states, the three resulting expressions of molecular weight can be solved for the nitrogen and carbon dioxide concentrations in the gas mixture.
摘要:
A method for ultrasonic measurement of the running time and quantity of a flowing fluid is provided, in which the running time of an ultrasonic signal (70) is measured counter to and in a direction of the flow (5), wherefrom the flow rate of the fluid is determined. Reflections of the ultrasonic signal (70) from particles in the fluid are also detected in order to determine a concentration of particles. A device for carrying out the method includes two ultrasonic transducers which can be switched from a transmission mode to a reception mode. The ultrasonic transducers in the transmission mode transmit ultrasonic signals that are received by the ultrasonic transducers in the reception mode once the signal (70) has penetrated the fluid to be analyzed. At least one of the ultrasonic transducerscan be switched from the transmission mode to the reception mode so that it can receive reflections (E1, E2, E3) of its transmitted signal. Additional transducers can be provided that also receive the reflections.
摘要:
The present invention includes a method and apparatus for detecting humans or human remains by analyzing air, fluid, or soil using electronic sensor technology, including surface acoustic-wave gas sensor technology. The method determines the presence and concentration of the target compound (or a class of compounds) associated with humans or human decomposition. Diagnostic software is used to identify target compounds where a stored library of signatures is compared to the signature obtained from the system. Signal processing and neural networks are preferably utilized in the analysis.
摘要:
Methods for inferentially determining various properties of a gas mixture, when the speed of sound in the gas is known at an arbitrary temperature and pressure. The method can be applied to natural gas mixtures, where the known parameters are the sound speed, temperature, pressure, and concentrations of any dilute components of the gas. The method uses a set of reference gases and their calculated density and speed of sound values to estimate the density of the subject gas. Additional calculations can be made to estimate the molecular weight of the subject gas, which can then be used as the basis for heating value calculations. The method may also be applied to inferentially determine density and molecular weight for gas mixtures other than natural gases.
摘要:
A computer product for determining thermodynamic properties of a natural gas hydrocarbon, when the speed of sound in the gas is known at an arbitrary temperature and pressure. Thus, the known parameters are the sound speed, temperature, pressure, and concentrations of any dilute components of the gas. The method uses a set of reference gases and their calculated density and speed of sound values to estimate the density of the subject gas. Additional calculations can be made to estimate the molecular weight of the subject gas, which can then be used as the basis for mass flow calculations, to determine the speed of sound at standard pressure and temperature, and to determine various thermophysical characteristics of the gas.
摘要:
The present invention provides a distributed sensing system in a networked environment for identifying an analyte, including a first sensor array connected to the network comprising sensors capable of producing a first response in the presence of a chemical stimulus; a second sensor array connected to the network comprising sensors capable of producing a second response in the presence of a physical stimulus; and a computer comprising a resident algorithm. The algorithm indicates or selects the most relevant sensor in the network to identify the analyte. The sensors can be separated over large spatial areas, wherein the sensor arrays are networked. Suitable networks include a computer local area network, an intranet or the Internet.
摘要:
An apparatus for monitoring a gas supply connection to a mechanical breathing aid has an in-line housing containing a measurement chamber for receiving gas from the gas supply and a transceiver arrangement) operable to emit acoustic energy into and to detect emitted acoustic energy propagated through the measurement chamber. A comparator is operably connected to the transceiver arrangement to receive therefrom a signal dependent on an amplitude of detected energy and generates a control signal from a comparison of the received signal with a reference signal indicative of a target gas usable by a flow control valve, also located within the housing, to inhibit a gas flow through the breathing aid if a gas other than the target gas is present.
摘要:
Methods of indirectly measuring the nitrogen concentration in a natural gas by heating the gas. In two embodiments, the heating energy is correlated to the speed of sound in the gas, the diluent concentrations in the gas, and constant values, resulting in a model equation. Regression analysis is used to calculate the constant values, which can then be substituted into the model equation. If the diluent concentrations other than nitrogen (typically carbon dioxide) are known, the model equation can be solved for the nitrogen concentration.