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A flowrate measurement method for air-water two-phase flow is developed using an Electrical Resistance Tomography (ERT) sensor and a Venturi meter. With the conductance values measured by the ERT sensor, the real-time flow pattern is identified and the voidage is also calculated. The Butterworth correlation is applied to calculate the mass quality from the voidage value, and then six Venturi measurement...
The mismatch uncertainty in microwave power sensor calibration system is analyzed. Propagation of uncertainties from the reflection coefficients in real and imaginary format are considered. Monte Carlo method (MCM) is used to estimate the probability distribution function (PDF) of the mismatch factor, which is found to be non-Gaussian for small reflection coefficient values. The mismatch uncertainties...
An electronic system based on a microcontroller architecture devoted to interfacing an Ultra Low Power (ULP) Metal OXide (MOX) gas sensor is presented. The circuit controls the operating temperature and manages the acquired data. A Pulse Width Modulation (PWM) signal with variable duty cycle is used to provide power to the heating resistor in order to set the desired operating temperature. The heating...
This paper reports recent advances in the optimisation of intrusive electrostatic sensors for the continuous velocity measurement of particles in pneumatic conveying pipelines. The effects of electrode dimensions and intrusion depth on sensor signals and correlation based velocity measurement have been investigated. Different cross sectional shapes of the electrodes have been compared. The optimum...
A measurement system is developed for the parameter detection and flow characterization of gas-liquid two-phase flow in micro-channel. Electrical capacitance measurement system and optical measurement system are designed for the micro-channels with different inner diameters of 4.0 mm, 3.1 mm and 1.8 mm respectively. In experiment, bubble flow, stratified flow, slug flow and annular flow are observed...
The characterization of hybrid aluminium / Carbon Fiber Reinforced Plastics (CFRP) sheets using multi-frequency eddy current sensors is presented in this paper. Both air-cored circular sensors and highly directional ferrite-cored sensors are designed for bulk conductivity measurements and directionality characterization. An analytical model describing the interaction of the circular sensors with the...
This paper presents the latest development in the velocity measurement of pulverized coal and biomass fuels in pneumatic pipelines using electrostatic sensors in combination with correlation signal processing techniques. A comparative study of electrostatic sensors with circular and rod electrodes was conducted on a 94mm bore horizontal pipeline feeding a 4 MW industrial scale furnace. Experimental...
A new strategy applying polynomial chaos theory (PCT) to diagnose sensor failure is presented in this paper. Using PCT and uncertainty of parameters, the original state space model of a system is expanded to PCT domain. Variations of sensor output due to parameter uncertainty are calculated by a PCT estimator and presented as PCT output boundaries based on the probability density function (PDF) of...
The instrumentation technologies required to achieve optimized combustion in pulverized fuel power plants represent an important challenge under increasing economical and environmental pressures. The present paper reports on the final results of a British government funded project to bring together various new and emerging sensing technologies aimed at achieving this goal. Both fuel flow and burner...
A direct digital converter that provides a digital output, proportional to the measurand being sensed by a single active element resistive sensor is presented in this paper. To accomplish this task, the structure and the switching sequence of a conventional dual slope, analog to digital converter (DSADC) is appropriately altered so that the altered DSADC accepts the resistance of the sensor as an...
Inverters are used to create single or polyphase AC voltages from a DC supply. A very common application for single-phase inverters are so-called "uninterruptable power supplies" (UPS) for computers and other critical loads. For sinusoidal AC outputs, the magnitude, frequency, and phase should be controllable. The purpose of this research, in collaboration with Astrid Energy Enterprises,...
This paper proposes the use of Vernier technique to improve the performance of direct interface circuits based on measuring the charging or discharging time of an RC circuit that includes the sensor. The proposed Vernier technique either improves the resolution determined by quantization of the digital timer or reduces the cost, measuring time, and power consumption of the circuit while preserving...
Ground water level measurements are very important for a wide range of applications in geosciences, agriculture, environment monitoring and mining industry. Currently, reliable and automatic ground water level measurements have not been realized. This paper presents the simulation and design of a segmented resistance sensor for measuring ground water level. Based on this sensor design, we have developed...
Disconnector switching operations in large gas insulated switchgear (GIS) systems may cause very fast transients overvoltages (VFTO), which produce dielectric stress to transformer connecting with the disconnector. A VFTO bushing sensor is developed to measure the VFTO at the transformer entrance. Since the high frequency ratio of the bushing sensor is not constant, calibration before the field measurement...
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