The Experts below are selected from a list of 2901 Experts worldwide ranked by ideXlab platform
J Tapson - One of the best experts on this subject based on the ideXlab platform.
-
A SIMPLE Force Balance ACCELEROMETER/SEISMOMETER BASED ON A TUNING FORK DISPLACEMENT SENSOR
2020Co-Authors: D Stuart-watson, J TapsonAbstract:Seismometers and MEMS accelerometers use the Force-Balance Principle to obtain measurements. In these instruments the displacement of a mass object by an unknown Force is sensed using a very highresolution displacement sensor. The position of the object is then stabilised by applying an equal and opposite Force to it. The magnitude of the stabilising Force is easily measured, and is assumed to be equivalent to the unknown Force. These systems are critically dependent on the displacement sensor. In this paper we use a resonant quartz tuning fork as the sensor. The tuning fork is operated so that its oscillation is lightly damped by the proximity of the movable mass object. Changes in the position of the mass object cause changes in the phase of the fork's resonance; this is used as the feedback variable in controlling the mass position. We have developed a novel acceleration sensor using this Principle. The mass object is a piezoelectric bimorph diaphragm which is anchored around its perimeter, allowing direct electronic control of the displacement of its centre. The tuning fork is brought very close to the diaphragm centre, and is connected into a self-oscillating feedback circuit which has phase and amplitude as outputs. The diaphragm position is adjusted by a feedback loop, using phase as the feedback variable, to keep it in a constant position with respect to the tuning fork. The measured noise for this sensor is approximately 10.0 mg in a bandwidth of 100 Hz, which is substantially better than equivalent commercial systems
D Stuart-watson - One of the best experts on this subject based on the ideXlab platform.
-
A SIMPLE Force Balance ACCELEROMETER/SEISMOMETER BASED ON A TUNING FORK DISPLACEMENT SENSOR
2020Co-Authors: D Stuart-watson, J TapsonAbstract:Seismometers and MEMS accelerometers use the Force-Balance Principle to obtain measurements. In these instruments the displacement of a mass object by an unknown Force is sensed using a very highresolution displacement sensor. The position of the object is then stabilised by applying an equal and opposite Force to it. The magnitude of the stabilising Force is easily measured, and is assumed to be equivalent to the unknown Force. These systems are critically dependent on the displacement sensor. In this paper we use a resonant quartz tuning fork as the sensor. The tuning fork is operated so that its oscillation is lightly damped by the proximity of the movable mass object. Changes in the position of the mass object cause changes in the phase of the fork's resonance; this is used as the feedback variable in controlling the mass position. We have developed a novel acceleration sensor using this Principle. The mass object is a piezoelectric bimorph diaphragm which is anchored around its perimeter, allowing direct electronic control of the displacement of its centre. The tuning fork is brought very close to the diaphragm centre, and is connected into a self-oscillating feedback circuit which has phase and amplitude as outputs. The diaphragm position is adjusted by a feedback loop, using phase as the feedback variable, to keep it in a constant position with respect to the tuning fork. The measured noise for this sensor is approximately 10.0 mg in a bandwidth of 100 Hz, which is substantially better than equivalent commercial systems
Junfeng Zhang - One of the best experts on this subject based on the ideXlab platform.
-
a physics based estimation of mean curvature normal vector for triangulated surfaces
Proceedings of the International Geometry Center, 2019Co-Authors: Mirza Cenanovic, Junfeng ZhangAbstract:In this note, we derive an approximation for the mean curvature normal vector on vertices of triangulated surface meshes from the Young-Laplace equation and the Force Balance Principle. We then demonstrate that the approximation expression from our physics-based derivation is equivalent to the discrete Laplace-Beltrami operator approach in the literature. This work, in addition to providing an alternative expression to calculate the mean curvature normal vector, can be further extended to other mesh structures, including non-triangular and heterogeneous meshes.
Mirza Cenanovic - One of the best experts on this subject based on the ideXlab platform.
-
a physics based estimation of mean curvature normal vector for triangulated surfaces
Proceedings of the International Geometry Center, 2019Co-Authors: Mirza Cenanovic, Junfeng ZhangAbstract:In this note, we derive an approximation for the mean curvature normal vector on vertices of triangulated surface meshes from the Young-Laplace equation and the Force Balance Principle. We then demonstrate that the approximation expression from our physics-based derivation is equivalent to the discrete Laplace-Beltrami operator approach in the literature. This work, in addition to providing an alternative expression to calculate the mean curvature normal vector, can be further extended to other mesh structures, including non-triangular and heterogeneous meshes.
Fa Yang - One of the best experts on this subject based on the ideXlab platform.
-
a novel lift off diameter model for boiling bubbles in natural gas liquids transmission pipelines
Energy Reports, 2020Co-Authors: Wenlong Jia, Fa YangAbstract:Abstract The pipeline is a convenient and safe way to transport natural gas liquids (NGLs). However, the NGL is easy to boil due to the variations of pressures and temperatures along the pipeline. The bubble lift-off diameter is an essential parameter to calculate the mass and heat transfer rates between vapor and liquid phases for the NGL two-phase saturated boiling flow. This paper proposed a novel bubble lift-off diameter model based on the Force-Balance Principle of bubbles, which considers the effects of the pressure, shear lift Force, unstable drag Force, surface tension, gravity Force, buoyancy Force, gas-phase density, bubble volume, bubble flow velocity, and bubble growth time on the bubble’s lift-off diameters at various pipe inclination angles. A total of 136 experimental data points are applied to validate the new model. Results demonstrate that the average relative deviation (ARD) between the experimental bubble’s lift-off diameters and calculated values based on the new model is in the range from 5.75% to 29.95%. In contrast, for horizontal and vertical pipes, the minimum ARDs of seven existing models (Fritz, Kocamustaf, Zeng, Lee, Situ, Hamzekhani, Chen models) are in the range from 19.42% to 42.58%, respectively. Moreover, the in-depth Force analysis results reveal that the shear lift Force, buoyancy Force, drag Force and surface tension Force are dominant factors affecting the bubble lift-off diameters in inclined pipes. The new model provides an effective method to calculate the bubble lift-off diameter in the pipe at various inclination angles, overcoming the deficiencies of most existing models that only can be applied to either horizontal or vertical pipes.