An electric measurement method and apparatus for detecting a mass by an electric capacity (permittivity) or a material's dielectric constant, or alternatively, electric inductance (permeability). The mass may be any phase or combination of phases. The mass may be stationary or flowing. It may comprise discrete particles such as grain, or manufactured products such as ball bearings or threaded fasteners, etc. The mass may be a flow element in a rotameter or similar flow measurement device. The sensor comprises a volume which may be completely full or only partially full of the material. The material may be discrete components or a continuum. Sensor signals may be received by existing planter monitoring systems. In some embodiments the flow sensors are positioned external to the application port. In some embodiments sensors may be utilized which are responsive to the refractive index variation of specific chemicals.

An electric measurement method and apparatus for detecting a mass by an electric capacity (permittivity) or a material's dielectric constant, or alternatively, electric inductance (permeability). The mass may be any phase or combination of phases. The mass may be stationary or flowing. It may comprise discrete particles such as grain, or manufactured products such as ball bearings or threaded fasteners, etc. The mass may be a flow element in a rotameter or similar flow measurement device. The sensor comprises a volume which may be completely full or only partially full of the material. The material may be discrete components or a continuum. Sensor signals may be received by existing planter monitoring systems. In some embodiments the flow sensors are positioned external to the application port. In some embodiments sensors may be utilized which are responsive to the refractive index variation of specific chemicals.

An electrochemical pH sensor for measuring pH in a low buffer and/or low ionic strength analyte where the electrochemical pH sensor comprises an electrode coupled with a phenolic redox species and the chemistry of the redox species provides for hydrogen bonding to one or more sulphur atoms of the redox species.

A fluid sensing system includes a sensing element having a positive temperature coefficient of resistance. The system also includes a switch which is switchable between an open position which prevents current from passing and a closed position which permits current to pass. An inductor is connected electrically in series between the switch electric output and the sensing element and a diode is connected electrically in series between the sensing element and the inductor such that an output of the diode is between the switch and the inductor. A hysteretic controller changes the switch from the open position to the closed position when current passing to the sensing element falls to a lower current threshold and changes the switch from the closed position to the open position when current passing to the sensing element rises to an upper current threshold. A voltmeter measures voltage across the sensing element.

A fluid sensing system includes a sensing element having a positive temperature coefficient of resistance. The system also includes a switch which is switchable between an open position which prevents current from passing and a closed position which permits current to pass. An inductor is connected electrically in series between the switch electric output and the sensing element and a diode is connected electrically in series between the sensing element and the inductor such that an output of the diode is between the switch and the inductor. A hysteretic controller changes the switch from the open position to the closed position when current passing to the sensing element falls to a lower current threshold and changes the switch from the closed position to the open position when current passing to the sensing element rises to an upper current threshold. A voltmeter measures voltage across the sensing element.

An estimate of interfacial areas between the liquid and gas, liquid and wall, and gas and wall in two phase flow is determined using a standard 2D sensor in a fashion to infer 3D information about the liquid/vapor profile when the sensor length is much longer than the diameter. Cross-sectional flow areas for the gas and liquid are also estimated as a function of the axial dimension of the sensor, and the centroid of the mass in the sensor element can also be estimated. An electric capacitance tomography (ECT) system creates tomograms of the flow inside a sensor, and estimates of 3D physical area information are produced from the tomograms.

An estimate of interfacial areas between the liquid and gas, liquid and wall, and gas and wall in two phase flow is determined using a standard 2D sensor in a fashion to infer 3D information about the liquid/vapor profile when the sensor length is much longer than the diameter. Cross-sectional flow areas for the gas and liquid are also estimated as a function of the axial dimension of the sensor, and the centroid of the mass in the sensor element can also be estimated. An electric capacitance tomography (ECT) system creates tomograms of the flow inside a sensor, and estimates of 3D physical area information are produced from the tomograms.

Disclosed are improved micro-electrochemical sensor structures that uses cyclic voltammetry (CV) to perform electrochemical measurements on gaseous volatile organic compounds (VOC). The improved sensor structures include a Ag reference electrode layer and an adhesion SU-8 layer. Operationally, the oxidation of the Ag layer provides a reference potential that is used to determine the redox reactions occurring on the surface of Pt electrodes exposed to a flow of gaseous VOC. Experimentally, our improved sensor was used to detect methane dissolved in N2. The results show clear and reproducible oxidation signals that were attributed to the presence of methane in the gas flow. The position of this signal for methane was compared to CO, and was found to be clearly separated from it, proving the speciation capabilities of the sensor. In addition, our experiments showed that it is possible to use the current value to quantify the detected molecule in the gas flow.

Disclosed are improved micro-electrochemical sensor structures that uses cyclic voltammetry (CV) to perform electrochemical measurements on gaseous volatile organic compounds (VOC). The improved sensor structures include a Ag reference electrode layer and an adhesion SU-8 layer. Operationally, the oxidation of the Ag layer provides a reference potential that is used to determine the redox reactions occurring on the surface of Pt electrodes exposed to a flow of gaseous VOC. Experimentally, our improved sensor was used to detect methane dissolved in N2. The results show clear and reproducible oxidation signals that were attributed to the presence of methane in the gas flow. The position of this signal for methane was compared to CO, and was found to be clearly separated from it, proving the speciation capabilities of the sensor. In addition, our experiments showed that it is possible to use the current value to quantify the detected molecule in the gas flow.

An electrical impedance tomography based flow monitoring system includes a flow accepting pipe having a cylindrical grid of mn electrodes, wherein m is an integer greater than 3 representing a number of circumferential grid positions and n is an integer greater than 2 representing a number of axial grid positions. Each combination of adjacent circumferential grid positions and adjacent axial grid positions defines a cell having four electrodes electrically connectable in various combinations by a switch, and the switches are set to connect the electrodes into multiple axially-extending arrays. The system further comprises a controller coupled to the multiple axially-extending arrays to acquire multi-point electrical tomography measurements, wherein the controller processes the measurements to derive a monitored quantity.