Provided are: an electrode for a gas sensor formed as a porous electrode so as to stably allow reduction in electrode resistance for excellent low-temperature activity; and a gas sensor. The electrode (108, 110) for the gas sensor is adapted for use on a surface of a solid electrolyte body (109), which is predominantly formed of zirconia, and contains particles (2) of a noble metal or an alloy thereof, first ceramic particles (4) of stabilized zirconia or partially stabilized zirconia and second ceramic particles (6) of one or more selected from the group consisting of Al.sub.2O.sub.3, MgO, La.sub.2O.sub.3, spinel, zircon, mullite and cordierite, wherein the second ceramic particles are contained in an amount smaller than that of the first ceramic particles.

An oil void fraction is measured by a simple way. A method of measuring an oil void fraction comprises a step of obtaining each oil void fraction of a plurality of sample oils, the void fraction thereof already-known, that are introduced into a closed space, compressing each sample oil with a predetermined pressure and measuring a volume change of the sample oil when compressed, and obtaining a calibration line for each sample oil, that is a linear function by connecting values represented by a product of the pressure at 0 kPa and the volume change plotted against the pressure when it is compressed to the predetermined pressure, a step of obtaining a value of a test oil sample having an unknown void fraction, that is represented by a product of the pressure at 0 kPa and the volume change plotted against the pressure when it is compressed to the predetermined pressure; and a step of determining the unknown void fraction of the test oil sample by comparing the value of the test sample oil to the calibration line of each sample oil.

An oil void fraction is measured by a simple way. A method of measuring an oil void fraction comprises a step of obtaining each oil void fraction of a plurality of sample oils, the void fraction thereof already-known, that are introduced into a closed space, compressing each sample oil with a predetermined pressure and measuring a volume change of the sample oil when compressed, and obtaining a calibration line for each sample oil, that is a linear function by connecting values represented by a product of the pressure at 0 kPa and the volume change plotted against the pressure when it is compressed to the predetermined pressure, a step of obtaining a value of a test oil sample having an unknown void fraction, that is represented by a product of the pressure at 0 kPa and the volume change plotted against the pressure when it is compressed to the predetermined pressure; and a step of determining the unknown void fraction of the test oil sample by comparing the value of the test sample oil to the calibration line of each sample oil.

A system for fan stress tracking according to an example of the present disclosure includes, among other things, a computing device that has a memory and a processor. The computing device is operable to execute a data module and a comparison module. The data module is operable to access data corresponding to a sensed value of an engine inlet parameter, and is operable to access data corresponding to a fan stress fatigue ratio profile. The fan stress fatigue ratio profile is defined with respect to at least one fan blade. The comparison module is operable to associate the sensed value of the engine inlet parameter with a stress value according to the fan stress fatigue ratio profile. The comparison module is operable to determine whether the stress value meets at least one predetermined criterion.

A system for fan stress tracking according to an example of the present disclosure includes, among other things, a computing device that has a memory and a processor. The computing device is operable to execute a data module and a comparison module. The data module is operable to access data corresponding to a sensed value of an engine inlet parameter, and is operable to access data corresponding to a fan stress fatigue ratio profile. The fan stress fatigue ratio profile is defined with respect to at least one fan blade. The comparison module is operable to associate the sensed value of the engine inlet parameter with a stress value according to the fan stress fatigue ratio profile. The comparison module is operable to determine whether the stress value meets at least one predetermined criterion.

The present disclosure provides a portable power tool. The power tool includes a tool body, a tool assembly and a gas pressure detection assembly. The tool assembly includes a tool bit furnished detachably in an end of the tool body. The gas pressure detection assembly is furnished detachably in another end of the tool body. The gas pressure detection assembly is communicatively coupled to the tool body.

The present disclosure provides a portable power tool. The power tool includes a tool body, a tool assembly and a gas pressure detection assembly. The tool assembly includes a tool bit furnished detachably in an end of the tool body. The gas pressure detection assembly is furnished detachably in another end of the tool body. The gas pressure detection assembly is communicatively coupled to the tool body.

A system operating based on Knudsen thermal force includes a microelectromechanical (MEMS) gas sensor, the MEMS gas sensor includes a substrate. The sensor further includes at least one stationary assembly fixedly coupled to the substrate, the at least one stationary assembly terminating at corresponding pads configured to receive an electrical current for heating the at least one stationary assembly. Additionally, the sensor includes at least one moveable assembly disposed above the substrate and biased to move substantially according to a main axis and juxtaposed with the at least one stationary assembly.

A method of determining density of a fluid within a system includes actuating a piston of a hydraulic cylinder at a target velocity. Additionally, the method includes determining differential pressure and volumetric flow rate of the fluid flowing through an orifice under actuation of the piston. The density of the fluid is determined based on the first differential pressure and the volumetric flow rate of the fluid, which is used by the system to regulate a mass flow rate of fluid within the system.

Methods and apparatuses for determining the swell of a subterranean formation sample when contacted with a fluid at subterranean conditions.