A Non-Intrusive Pressure Sensor by Detecting Multiple Longitudinal Waves

Pressure vessels are widely used in industrial fields, and some of them are safety-critical components in the system - for example, those which contain flammable or explosive material. Therefore, the pressure of these vessels becomes one of the critical measurements for operational management. In the paper, we introduce a new approach to the design of non-intrusive pressure sensors, based on ultrasonic waves. The model of this sensor is built based upon the travel-time change of the critically refracted longitudinal wave (LCR wave) and the reflected longitudinal waves with the pressure. To evaluate the model, experiments are carried out to compare the proposed model with other existing models. The results show that the proposed model can improve the accuracy compared to models based on a single wave

A study of acoustic emission technique for concrete damage detection

The Acoustic emission (AE) technique, as one of non-intrusive and nondestructive evaluation techniques, acquires and analyzes the signals emitting from deformation or fracture of materials/structures under service loading. The AE technique has been successfully applied in damage detection in various materials such as metal, alloy, concrete, polymers and other composite materials. In this study, the AE technique was used for detecting crack behavior within concrete specimens under mechanical and environmental frost loadings. The instrumentations of the AE system used in this study include a low-frequency AE sensor, a computer-based data acquisition device and a preamplifier linking the AE sensor and the data acquisition device. The AE system purchased from Mistras Group was used in this study. The AE technique was applied to detect damage with the following laboratory tests: the pencil lead test, the mechanical three-point single-edge notched beam bending (SEB) test, and the freeze-thaw damage test. Firstly, the pencil lead test was conducted to verify the attenuation phenomenon of AE signals through concrete materials. The value of attenuation was also quantified. Also, the obtained signals indicated that this AE system was properly setup to detect damage in concrete. Secondly, the SEB test with lab-prepared concrete beam was conducted by employing Mechanical Testing System (MTS) and AE system. The cumulative AE events and the measured loading curves, which both used the crack-tip open displacement (CTOD) as the horizontal coordinate, were plotted. It was found that the detected AE events were qualitatively correlated with the global force-displacement behavior of the specimen. The Weibull distribution was vii proposed to quantitatively describe the rupture probability density function. The linear regression analysis was conducted to calibrate the Weibull distribution parameters with detected AE signals and to predict the rupture probability as a function of CTOD for the specimen. Finally, the controlled concrete freeze-thaw cyclic tests were designed and the AE technique was planned to investigate the internal frost damage process of concrete specimens

Contextualising water use in residential settings: a survey of non-intrusive techniques and approaches

Water monitoring in households is important to ensure the sustainability of fresh water reserves on our planet. It provides stakeholders with the statistics required to formulate optimal strategies in residential water management. However, this should not be prohibitive and appliance-level water monitoring cannot practically be achieved by deploying sensors on every faucet or water-consuming device of interest due to the higher hardware costs and complexity, not to mention the risk of accidental leakages that can derive from the extra plumbing needed. Machine learning and data mining techniques are promising techniques to analyse monitored data to obtain non-intrusive water usage disaggregation. This is because they can discern water usage from the aggregated data acquired from a single point of observation. This paper provides an overview of water usage disaggregation systems and related techniques adopted for water event classification. The state-of-the art of algorithms and testbeds used for fixture recognition are reviewed and a discussion on the prominent challenges and future research are also included

Monitoring Corrosion Of A One Inch Ball Valve In A Hydraulic Loop Using Ultrasonic Technology

ABSTRACT Ball valves with carbon steel bodies that help modulate flow rates are valuable parts in the process chemical industry. While corrosion monitoring is widely studied, there is not much information available regarding corrosion monitoring of control valves, as referenced in the literature review for this dissertation. This research investigated some foundational blocks for how corrosion can be monitored for a carbon steel body ball valve using ultrasonic technology. Topics that were addressed during this research include: Monitoring corrosion in a carbon steel 1inch ball valve in a constant flow rate environment, in the presence of sodium chloride solution, mixtures of sodium chloride and acetic acid with pH ranging from 4 to 8. Monitoring and analysis of the corrosion impact for the inlet and outlet of carbon steel ball valve using handheld ultrasonic thickness meter in constant flow conditions. Embedded ultrasonic transducers on carbon steel control valve body for online corrosion monitoring. Three experiments were conducted under various corrosive environment namely NaCl, acetic acid and NaCl mixtures for a total of 1,872 hours. Flow rates for these experiments were kept constant while process variables such as pressure, temperature, flow rates, total dissolved solids and power of hydrogen were measured. Microscopic images of the inlet and outlet of the valve were reviewed to validate corrosion characteristics of the valve body. Ultrasonic transducers were used to collect thickness data on the valve body in one experiment and embedded permanently for 648 hours while thickness measurements were monitored during the second and third experiments. Statistical tools were used to analyze data from thickness measurements. The tools used are normal distribution, probability and regression. The inlet and outlet thickness measurements for the three experiments were not normally distributed as expected. The thickness loss for both inlet and outlet locations where thickness readings were taken on the valve for all three experiment, showed that the thickness losses were nonlinear in nature as expected, although for the 240 hours of run with the ultrasonic transducer embedded on the valve, the outlet readings were very close to linear. Thickness measurements were tested against ambient conditions and valve positions which include, temperature, air pressure, noise, vibration and varying valve position. Apart from a high temperature at 300℉, which had an impact on the ultrasonic thickness readings, air pressure, noise exposure, vibration and changing valve position did not have adverse impacts on the measured thickness. These investigations have proven that, ultrasonic transducers can be embedded on ball valves with carbon steel bodies, to monitor both corrosion rates and total corrosion. These experiments will build the foundation for the next generation of carbon steel ball valves which have ultrasonic technology embedded to monitor corrosion online and in real time

Contactless Sensing of Water Properties for Smart Monitoring of Pipelines

A key milestone for the pervasive diffusion of wireless sensing nodes for smart monitoring of water quality and quantity in distribution networks is the simplification of the installation of sensors. To address this aspect, we demonstrate how two basic contactless sensors, such as piezoelectric transducers and strip electrodes (in a longitudinal interdigitated configuration to sense impedance inside and outside of the pipe with potential for impedimetric leak detection), can be easily clamped on plastic pipes to enable the measurement of multiple parameters without contact with the fluid and, thus, preserving the integrity of the pipe. Here we report the measurement of water flow rate (up to 24 m(3)/s) and temperature with ultrasounds and of the pipe filling fraction (capacitance at 1 MHz with similar to cm(3) resolution) and ionic conductivity (resistance at 20 MHz from 700 to 1400 mu S/cm) by means of impedance. The equivalent impedance model of the sensor is discussed in detail. Numerical finite-element simulations, carried out to optimize the sensing parameters such as the sensing frequency, confirm the lumped models and are matched by experimental results. In fact, a 6 m long, 30 L demonstration hydraulic loop was built to validate the sensors in realistic conditions (water speed of 1 m/s) monitoring a pipe segment of 0.45 m length and 90 mm diameter (one of the largest ever reported in the literature). Tradeoffs in sensors accuracy, deployment, and fabrication, for instance, adopting single-sided flexible PCBs as electrodes protected by Kapton on the external side and experimentally validated, are discussed as well

The use of ultrasound for detecting particles suspended in lubricant and hydraulic fluids

Imperial Users onl

Sensitivity of the mussel Mytilus edulis to substrate‑borne vibration in relation to anthropogenically generated noise

© 2015 Inter-Research. Many anthropogenic activities in the oceans involve direct contact with the seabed (for example pile driving), creating radiating particle motion waves. However, the consequences of these waveforms to marine organisms are largely unknown and there is little information on the ability of invertebrates to detect vibration, or indeed the acoustic component of the signal. We quantified sensitivity of the marine bivalve Mytilus edulis to substrate-borne vibration by exposure to vibration under controlled conditions. Sinusoidal excitation by tonal signals at frequencies within the range 5 to 410 Hz was applied during the tests, using the 'staircase' method of threshold determination. Thresholds were related to mussel size and to seabed vibration data produced by anthropogenic activities. Clear behavioural changes were observed in response to the vibration stimulus. Thresholds ranged from 0.06 to 0.55 m s -2 (acceleration, root mean squared), with valve closure used as the behavioural indicator of reception and response. Thresholds were shown to be within the range of vibrations measured in the vicinity of anthropogenic operations such as pile driving and blasting. The responses show that vibration is likely to impact the overall fitness of both individuals and mussel beds of M. edulis due to disruption of natural valve periodicity, which may have ecosystem and commercial implications. The observed data provide a valuable first step to understanding the impacts of such vibration upon a key coastal and estuarine invertebrate which lives near industrial and construction activity, and illustrate that the role of seabed vibration should not be underestimated when assessing the impacts of noise pollution

2D and 3D visualization of acoustic waves by optical feedback interferometry

The visualization of physical phenomena is one of the challenges that researchers are trying to overcome by designing and implementing different sensors that provide information close to realitythrough changes in one of the parameters they measure. Historically, the visualization of variations in physical phenomena has allowed for a better understanding of the problem being studied and has changed our perception of the world and ourselves forever. Over the last 300 years, in particular, many methods have been developed to visualize sound through a visual representation. In the field of acoustics, scientists have attempted to develop a visual representation of sound waves using transducers detecting two fundamental components of sound: sound pressure and particle velocity. In other words, the measurement of kinetic energy and potential, whose quantities provide information on the physical phenomenon of acoustic propagation. In this summary, we briefly present the work of the thesis entitled "2D and 3D Visualizations of Acoustic Waves by Optical Feedback Interferometry" in which a new visualization tool for acoustic phenomena was developed. This system is based on an optical sensor said reinjection in a laser diode and allows to reconstruct in 2D and 3D the image of a propagating acoustic wave. The manuscript is divided into 3 chapters: • a first chapter presents the known methods for the visualization of the acoustic phenomena and presents the context of the research carried out, • a second chapter, allows to detail the principle of measurement and its application to the realization of a two-dimensional image of the acoustic wave • finally, in the last chapter, we demonstrate how a tomographic method can be used to create a three-dimensional image