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The presence of electrostatic charge in a bubbling fluidized bed influences the operation of the bed. In order to maintain an effective operation, the electrostatic charges in different positions of the bed should be monitored. In this paper a wire-mesh electrostatic sensor is introduced to reconstruct the charge distribution in a bubbling fluidized bed. The wire-mesh sensor is fabricated by two mutually...
Thermoelectric Modules (TEM) are used in areas such as precision temperature control applications, cooling system, energy harvesting, etc. The fully characterization of TEM is very important, mainly with respect to its degradation. In order to evaluate degradation, thermal cycling application is one of the most used methods. In this work it is described a complete thermal-cycling testing platform...
The analysis of measurement uncertainty is necessary in every measurement process. In this paper, we suggest an approach to categorize and model the dominant sources of uncertainty and study the probabilistic propagation of the uncertainties in a 3D inspection using laser line scanners. To each point of the measurement point cloud, we associate a covariance matrix describing the corresponding dispersion...
To improve the anti-vibration performance of vortex flow meter, we propose a new design of vortex probe based on acceleration measurement. Mode and harmonic response analyses of probe structure are carried out by using finite element analysis software. Selections of material and optimized mechanical structure of probe are given by simulation results. Both simulation and experiment results indicate...
Fault diagnosis plays a significant role to ensure transmission efficiency and reliability of gearboxes. Considering the modulation feature of gearbox vibration signals, a demodulation analysis method based on variational mode decomposition (VMD) is proposed. Firstly, a multi-component signal is decomposed into a series of intrinsic mode functions (IMFs) via VMD to reduce the effect of noise and satisfy...
Over the past two decades, carbon nanotubes (CNTs) have attracted a great deal of interest owing to their superior electrical properties and they are being used in many engineering applications including highly sensitive strain sensors. However, realization of well-dispersed CNTs within the polymer matrix is challenging due to the strong tendency of carbon nanotubes to form bundles. Therefore, each...
A mode filter for LED-based gas absorption spectroscopy is shown. Two LEDs with different wavelengths are used for the measurement of gas concentrations. One wavelength for measurement and a second wavelength as reference. This allows to measure gases like NO2 (405nm) and SO2 (285nm). Different disturbances, like temperature, vibrations and the optical properties of LEDs require a mode filter to reduce...
Pressure sensitive mats provide an opportunity for non-intrusive continuous monitoring of patient health and physiology. Pressure sensitive mats have been used to analyze balance, bed transfers, pressure ulcers and sleep. This paper describes a model that can be used to measure the characteristics of pressure sensitive mats. The main contribution of this paper is the design and fabrication of a 2D...
Image processing and analysis is a potential tool for monitoring of activated sludge wastewater treatment plant. One of the important parameters to track the performance of activated sludge plant is sludge volume index (SVI). In this paper, image analysis based modeling is used to estimate the sludge volume index. Bright field microscopic images of activated sludge were segmented by integrating four...
Nuclear Magnetic Resonance (NMR) has been widely used in chemical analysis and medical diagnosis. In recent years, thanks to the development of the NMR instrumentation and the software for data analysis, it is becoming a useful tool for quality control in food industry. In this field several applications have been developed related to the compositional and structural analysis, authentication, packaging,...
Direct-reading instruments which can provide real-time PM2.5 measurements are widely used because they are cheap and easy to use. However, these direct-reading instruments suffer from zero drift problems and have to be calibrated before use. Direct-reading instruments based on average value measurement can't give a correct assessment of PM2.5 mass concentrations when particles' diameter changes greatly...
Nowadays, the presence of nonlinear devices cannot be neglected either for their growing numbers or for their effect on the distribution network. In particular, these devices will produce relevant harmonics, which can cause problems such as increase of losses, over-heating in the power transformer malfunction of the circuit switch and, generally, an untimely aging process of connected devices. As...
The conceptual entity that metrologists term the measurand is a model selected to represent the physical entity being measured. In a world of digital measurements, it should be defined first mathematically, and only then put into words. Human linguistic processes lack the precision required when all we do is use labels. In this paper, reactive power and frequency are used as examples. The act of measurement...
As more and more distributed generations existing in the grid, the directional overcurrent protection is required in the modern distribution network. The traditional method needs the voltage phasor as the reference that adds the cost. The current-only directional overcurrent protection can solve this problem to a certain extent. But, it can't recognize the fault direction when the direction of power...
In this paper, a new and high accuracy, dual-purpose Direct-Digital Converter (DDC) is presented. The proposed Switched-Capacitor (SC) DDC can be used to interface sensors whose electrical equivalent is (a) a capacitor Cx or (b) a resistor Rx or (c) Cx and Rx in parallel. Irrespective of (a)-(c), the DDC gives digital outputs proportional to Cx and Rx of the sensor. Capacitance-to-Digital Converters...
This paper investigates defects in photovoltaic cells and panels which cause notable losses in output performances. Here, the focus lies on the impact of hairline cracks which result in a remarkable drop of the available output current and, thus, the available output power. Firstly, samples were characterised with the help of synchronized thermography (ST) in order to localise and analyse the defects...
A new Resistance-to-Digital Converter (RDC) suitable for single element resistive sensors is presented in this paper. The proposed scheme is based on a relaxation oscillator circuit, which along with a timer-counter that measures the time intervals of oscillations, provides digital output proportional to the resistance of the sensor. In most of the existing RDCs, the output characteristic has gain,...
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