A thermal air flow sensor that produces less measurement error is provided. The thermal air flow sensor includes: a semiconductor substrate; a heating resistor, resistance temperature detectors, and an electrical insulator that includes a silicon oxide film, wherein the heating resistor, the resistance temperature detectors, and the electrical insulator are formed on the semiconductor substrate; and a diaphragm portion formed by removing a portion of the semiconductor substrate. The heating resistor and the resistance temperature detectors are formed on the diaphragm portion. The thermal air flow sensor further includes a silicon nitride film formed as the electrical insulator above the heating resistor and the resistance temperature detectors. The silicon nitride film has steps conforming to the patterns of the heating resistor and the resistance temperature detectors. The silicon nitride film has a multilayer structure.

Methods and apparatuses associated with an example flow sensing device are provided. In some examples, the flow sensing device may include a flow cap component and a sensor component. In some examples, the flow cap component may include a heating element disposed in a first layer of the flow cap component. In some examples, the sensor component may include at least one thermal sensing element disposed in a second layer of the sensor component. In some examples, the first layer and the second layer are noncoplanar. In some examples, the flow cap component may be bonded to a first surface of the sensor component to form a flow channel. In some examples, the first layer and the second layer may be noncoplanar and separated by the flow channel.

Methods and apparatuses associated with an example flow sensing device are provided. In some examples, the flow sensing device may include a flow cap component and a sensor component. In some examples, the flow cap component may include a heating element disposed in a first layer of the flow cap component. In some examples, the sensor component may include at least one thermal sensing element disposed in a second layer of the sensor component. In some examples, the first layer and the second layer are noncoplanar. In some examples, the flow cap component may be bonded to a first surface of the sensor component to form a flow channel. In some examples, the first layer and the second layer may be noncoplanar and separated by the flow channel.

An electronic utility gas meter using MEMS thermal mass flow sensor to meter gas custody transfer and MEMS gas thermal property sensor to compensate the metering values due to gas composition variations is disclosed in the present invention. The meter is designed to have a MEMS mass flow sensor to meter the city utility gas consumption independent of environmental temperature and pressure while a MEMS gas thermal property or dual gas thermal property sensors to compensate the tariff due to the gas composition variations for compliance with the current regulation requirements of tariff and remove the major concerns for the wide deployment of the thermal mass MEMS utility gas meters.

A microneedle probe for measuring a sap flow in a plant is disclosed, the microneedle probe including: a substrate; and a sensor unit which is installed on the substrate, generates heat, and measures a temperature that changes in accordance with a sap flow.

A microneedle probe for measuring a sap flow in a plant is disclosed, the microneedle probe including: a substrate; and a sensor unit which is installed on the substrate, generates heat, and measures a temperature that changes in accordance with a sap flow.

A thermal sensor device is configured to determine a fluid parameter of a fluid based on the heat transfer behavior of the fluid. The sensor device comprises one or more heaters and means for determining a response of the sensor device to heater power being supplied to the heaters. For detecting sensor faults, the sensor device is operated in two different modes of operation. First and second values (c.sub.static, c.sub.dynamic) of the same fluid parameter are determined in the two modes. A fault indicator value (F) is derived by comparing the first and second values. The first mode of operation may be a steady-state mode, the first value (c.sub.static) being based on a steady-state response of the sensor device to heater power being supplied to the heaters, and the second mode of operation may be a dynamic mode, the second value (c.sub.static) being based on a transient response.

A self-correcting pressure-based mass flow control apparatus includes outlet pressure sensing to enable correction for non-ideal operating conditions. Further the mass flow control apparatus having a fluid pathway, a shutoff valve in the fluid pathway, a reference volume in the fluid pathway, a first pressure measuring sensor in fluid communication with the reference volume, a first temperature measuring sensor providing a temperature signal indicative of the fluid temperature within the reference volume, a proportional valve in the fluid pathway, and a second pressure measuring sensor in fluid communication with the fluid pathway.

A self-correcting pressure-based mass flow control apparatus includes outlet pressure sensing to enable correction for non-ideal operating conditions. Further the mass flow control apparatus having a fluid pathway, a shutoff valve in the fluid pathway, a reference volume in the fluid pathway, a first pressure measuring sensor in fluid communication with the reference volume, a first temperature measuring sensor providing a temperature signal indicative of the fluid temperature within the reference volume, a proportional valve in the fluid pathway, and a second pressure measuring sensor in fluid communication with the fluid pathway.

A flow-rate sensor is provided with a lead frame, a semiconductor chip that is disposed on one surface of the lead frame, and in which a diaphragm including a void portion on the lead frame side is formed, a flow rate detecting unit that is formed on the one surface including the diaphragm of the semiconductor chip, and resin that includes a flow passage opening portion exposing at least a portion of the flow rate detecting unit formed on the diaphragm, and covers the lead frame and the semiconductor chip. A lower side resin portion of the resin covering another surface side of the lead frame, on an opposite side to the one surface side thereof, has a thinned portion that is thinner than a periphery thereof in a region facing a peripheral edge portion of the diaphragm.