Interior Void Classification in Liquid Metal using Multi-Frequency Magnetic Induction Tomography with a Machine Learning Approach

Identification of gas bubble, void detection and porosity estimation are important factors in many liquid metal processes. In steel casting, the importance of flow condition and phase distribution in crucial parts, such as submerged entry nozzle (SEN) and mould raises the needs to observe the phenomena. Cross-section of flow shapes can be visualised using the magnetic induction tomography (MIT) technique. However, the inversion procedure in the image reconstruction has either limited resolution or involving post-processing stages degrading its real-time capability. Additionally, when quantifying the void fraction or porosity, the image may not be required. This work proposes an interior void classifier based on multi-frequency mutual induction measurements with eutectic alloy GaInSn as a cold liquid metal model contained in a 3D printed plastic miniature of an SEN. The sensors consist of eight coils arranged in a circle encapsulating the column, providing combinatorial detection on conductive surface and depth. The datasets are induced voltage collections of several non-metallic inclusions (NMI) patterns in liquid metal static test and used to train a machine learning model. The model architectures are a fully connected neural network (FCNN) for 1D; and a convolutional neural network (CNN) for 2D data. The classifier using 1D data has been trained to provide 95% accuracy on this dataset. On the other hand, CNN classification using multi-dimensional data produces 96% of test accuracy. Refined with representative flow scenarios, the trained model could be deployed for an intelligent online control system of the liquid metal process

Noninvasive Conductivity and Temperature Sensing using Magnetic Induction Spectroscopy Imaging

The work presents a perspective in evaluating electromagnetic tomography reconstruction through a spectral eddy current imaging arrangement. Embarking from an established analytical basis, the spectroscopic relation of a metallic conductive body to its physical properties is revealed via multifrequency mutual impedance measurement. Characteristics are evident, from either modeling or experiment, on certain frequency ranges that discriminate the object's circumstances. Both the amplitude ratio and phase-contrast image spectrum show information on the conductivity and structure of a target considered pivotal for industrial applications. Two test cases are reported: liquid metal structure determination and contactless temperature evaluation of a remote/hidden medium/object. Using eddy current-based spectroscopic imaging data and appropriate calibration, this work, for the first time, demonstrates a novel thermal mapping system. This is a wireless and inductive-based temperature mapping device that can have great potential applications where none of the existing thermal measuring devices could work noninvasively. <br/

Ultrasound power measurement system design using PVDF sensor and FPGA technology

Ultrasound machine is widely used in industrial and medical institutions. With the purpose of avoiding the unwanted power exposed on human, ultrasound power meter is employed to measure output power of ultrasound machine for diagnostic, therapeutic and non-destructive testing purposes. The existing ultrasound power meter, however, is high-cost, low-resolution and only for specific machine. Radiation balance method consists of calculation and calibration complexity while the calorimetric produces inaccurate result compared to the standard. On the other hand, application of piezoelectric sensor in hydrophone-based measurement requires advancement on processing device and technique. This work deals with the development of ultrasound power measurement system on Field Programmable Gate Array (FPGA) platform. Polyvinylidene Fluoride (PVDF) was employed to sense medical ultrasonic signal. PVDF film’s behavior and its electro-acoustic model were observed. Signal conditioner circuit was then described. Next, a robust low-cost casing for PVDF sensor was built, followed by the proposal of the use of digital-system ultrasound processing algorithm. The simulated sensor provided 2.5 MHz to 8.5 MHz response with output amplitude of around 4 Vpp. Ultrasound analog circuits, after filtering and amplifying, provided frequency range from 1 MHz until 10 MHz with -5 V to +5 V voltage head-rooms to offer a wideband medical ultrasonic acceptance. Frequency from 500 kHz to 10 MHz with temperature span from 10 oC to 50 oC and power range from 1 mW/cm2 up to 10 W/cm2 (with resolution 0.05 mW/cm2) had been expected by using the established hardware. The test result shows that the platform is able to process 10 us ultrasound data with 20 ns time-domain resolution and 0.4884 mVpp magnitude resolutions. This waveform was then displayed in the personal computer’s (PCs) graphical user interface (GUI) and the calculation result was displayed on liquid crystal display (LCD) via microcontroller. The whole system represents a novel design of low-cost ultrasound power measurement system with high-precision capability for medical application. This may improve the existing power meters which have intensity resolution limitation (at best combination, of all products, utilize: 0.25 MHz - 10 MHz frequency coverage; 10 oC to 30 oC working temperature; 0 W/cm2 - 30 W/cm2 power range; 20 mW/cm2 resolution), neither having mechanism to handle the temperature disturbance nor possibility for further data analysis

Respiration Monitoring System of Lung Phantom Using Magnetic Sensor

Monitoring vital signs is substantial in healthcare to assist both diagnosis and treatment. This work proposes a means of telemonitoring system at initial stage to observe respiratory pattern on lung phantom. Magnetic sensor module LDC1000 is used to read inductance value of conductive material in relation to distance variation. Therefore, respiration pattern can be observed. In continuous mode, the inspiration inductance value is 8 uH, while expiration is 17 uH, with stoppage is 17 uH. For static measurement, the inspiration inductance value is 7.80 uH, while expiration is 16.46 uH and stoppage is 16.46 uH. Those values could be further referred for vital signs telemonitoring system design based on contactless and portable devices

Position Tracking for Static Target using Burst Signals with Time Difference of Arrival Method

Time difference of arrival (TDOA) is one of transmitter tracking method to find location or position based on the difference of arrival signals from transmitter to receiver in time domain. This work aims to find the position of a transmitter using TDOA method. Operating frequency used is amateur radio 144.100 MHz for sending and receiving burst signal. Time difference is calculated by using cross correlation function. Output parameters are distance and coordinate of Tx toward Rx. The transmitter position is calculated by hyperbolic and trigonometry equations, giving distance error of 30.49%. Further improvement would require two or more tracking position methods in order to obtain more accurate value

Implementation of Water Level Measuring Instruments as Flood Indicator in the Rice Fields of Teluklada Village

Flooding in rice fields often occurs as a result of overflowing rainwater or overflowing river water. In addition, irrigation also often overflows and inundates farmers' fields. The way that is often done to overcome this is usually done every few minutes to the fields. An automatic tool is needed that can be used to be able to monitor water level activities that occur in rice fields. In that case farmers can make the best and timely decisions when rice fields will be flooded. The design process of this tool is carried out in 2 stages, namely the area analysis stage and the design of the tool design which will be carried out with the characteristics of rice fields in Teluklada village. The Water Level Measuring Tool as a Flood Indicator in Rice Fields is designed as a flood indicator by utilizing the HCSR04 sensor work function to detect water rise that occurs. Residents who received the notification message were surprised when they first received the flood warning message and felt helped by the presence of this water level measuring instrument because it can monitor rice fields remotely

Design of a Low Cost Remotly Operated Vehicle with 3 Dof Navigation

One type of underwater robot is the ROV (Remotely Operated Vehicle) whose movements are controlled directly by humans from the water surface. In this paper, ROV prototype has been designed and tested with three DoF (Degrees of Freedom) and controlled by a joystick which is connected with UTP (Unshielded Twisted Pair) cables as data transmission between joystick with a microcontroller embedded in the robot. This prototype has 3 thrusters with 3 degrees of freedom, 1 rotational motion (heave) and 2 translational motion (yaw and surge), with direction of movement up, down, forward, backward, turn right, and turn left. Speed mode setting when forward movement on PWM (Pulse Width Modulation) 75% = 0,037 m/s, 90% = 0.053 m/s and 100% = 0,071 m/s, while the reverse speed by 75% = 0,034 m/s, 90% = 0.045 m/s and 100% = 0.059 m/s, when the ROV moves up is 0,042 m/s, down 0.032 m/s, turn right 9 o/s and turn left 15 o/s set with fixed PWM value, is 100%