Briefing: Disruptive socio-technical solutions to drive re-visualisation of water service provision

The UK Engineering and Physical Sciences Research Council has launched a £4 million, 5-year grand challenge multi-disciplinary research consortium (TWENTY65) to achieve sustainable clean water for all through the development and demonstration of disruptive socio-technical solutions. The aim of this transformative research is to drive re-visualisation of water service provision and revolutionise the way innovation is delivered in the water sector. This briefing introduces concepts of disruptive innovation that could lead to a new paradigm for water service provision

Microbial fuel cells directly powering a microcomputer

© 2019 The Authors Many studies have demonstrated that microbial fuel cells (MFC) can be energy-positive systems and power various low power applications. However, to be employed as a low-level power source, MFC systems rely on energy management circuitry, used to increase voltage levels and act as energy buffers, thus delivering stable power outputs. But stability comes at a cost, one that needs to be kept minimal for the technology to be deployed into society. The present study reports, for the first time, the use of a MFC system that directly and continuously powered a small application without any electronic intermediary. A cascade comprising four membrane-less MFCs modules and producing an average of 62 mA at 2550 mV (158 mW) was used to directly power a microcomputer and its screen (Gameboy Color, Nintendo®). The polarisation experiment showed that the cascade produced 164 mA, at the minimum voltage required to run the microcomputer (ca. 1.850 V). As the microcomputer only needed ≈70 mA, the cascade ran at a higher voltage (2.550 V), thus, maintaining the individual modules at a high potential (>0.55 V). Running the system at these high potentials helped avoid cell reversal, thus delivering a stable level of energy without the support of any electronics

Are you afraid of COVID-19? Motivation and engagement in infection–prevention behaviour in a UK community cohort during the first 2 years of the COVID-19 pandemic

Objectives: To investigate the relationship between motivation and COVID-19 infection–prevention behaviour during the first 2 years of the COVID-19 pandemic. Design: Prospective longitudinal online survey in a UK community-based cohort. Methods: During March/April 2020, n = 11,113 people, recruited via the HealthWise Wales research registry and social media advertising, completed the COVID-19 Public Experiences (COPE) study baseline survey, with follow-up at 3, 12, 18 and 24 months. Online questionnaires assessed COVID-19 infection–prevention behaviour, perceived susceptibility, fear, personal control over infection transmission and reliability of information from media and government. Repeated-measures ANOVA identified changes in motivation and behaviour over time. Multivariable regression models at each time point assessed associations between motivation and behaviour. Results: COVID-19 infection–prevention behaviour and motivational variables (fear of COVID-19, perceived susceptibility and perceived control) fluctuated over time as the disease and socio-political environment changed, decreasing overall by 24 months. Regression models for association between motivational variables and COVID-19 infection–prevention behaviour were statistically significant at three (F(10, 5981) = 76.69, p < .001, adjusted R2 .112), 12 (F(11, 3732) = 48.40, p < .001, adjusted R2 .122), 18 (F(11, 3665) = 108.34, p < .001, adjusted R2 .243) and 24 months (F(11, 3355) = 136.20, p < .001, adjusted R2 .306). Higher levels of fear, older age, lower perceived personal control over infection transmission, more trust in government and less trust in social media were associated with more infection–prevention behaviour. Conclusions: Motivation to engage in infection–prevention behaviour during a pandemic is multi-factorial and dynamic. Beliefs about infection and trust in government and media need to be considered in developing effective communication strategies

Perspective: a vision of a low-carbon water sector in 2050

Water is the new oil and carbon is the currency that will drive the water industry to make significant changes to reduce its carbon budgets. The industry will be a significant player in the carbon reduction commitment in 2010 and will contribute to the UK's carbon reduction targets. This paper presents a personal view of ways of driving a vision for a low-carbon water industry in 2050. It is recognised that a multi-faceted approach will be required that: builds on research, technology and skills development; requires policy and institutional reform to allow new approaches; requires cross-boundary cooperation and systems; builds stakeholder capacity to understand risk and mitigation; and provides financial support to incentivise a low-carbon approach. The paper discusses the potential business, social and infrastructure changes that may result and outlines how demand reduction, water-sensitive urban design (including community-based solutions) and significant changes to water industry operations could contribute to the low-carbon vision. The paper identifies the many barriers that inhibit a low-carbon approach and suggests that the climatic stresses of the future will contribute to the removal of these barriers and to a culture change in the stakeholder base. </jats:p

An investigation into ultrasonic waves in distance measurement

This study looks at the investigation into the distance measurement of ultrasonic waves. The purpose of the study is to determine a possible achievement of an accuracy of ±1 mm for a 40 kHz ultrasonic transducer in measuring distance through a series of controlled experiments with varying parameters. A comparison was done between the different forms of distance measuring devices to identify the advantages and disadvantages of Ultrasonic Distance Measuring Devices (UDMDs) against other distance measuring devices. Also, a comparison was done between available devices in the market to find out the accuracies and features specified on the devices. The study is limited to a scope of conducting indoor testing up to a range of 15 m, hence keeping factors like temperature and humidity constant as the experiments were conducted in the same laboratory. A review on literature was also included to form a basis for the design of the experiments. The study looks at the applications of ultrasonic specifically in air to work within the limitations of the project. The study also includes a review on the safety issues while working with similar types of frequencies and its possibilities of effects on pacemakers. The design of the experiments was discussed in detail and the apparatus and equipment used were presented. It was also decided to keep the transmitter fixed at one point for both the calibration phase and the main sets of experiments. The experiment was thus carried out with the parameters varied. The parameters included a direct line of sight between the transducers and a variation of the angles of roll, pitch and yaw applied to one transducer, which in this case is the transmitter. This variation in the study allows for a good basic understanding of the accuracies generated through varying orientations. The results were presented with the use of Statistical Package for the Social Sciences (SPSS). Error bars were in the form of 95% C.I. which provided useful information on the accuracy, reliability and capability of ultrasonic waves in distance measurement. The ultrasonic waves generated by the transducer were only capable of providing reliable accuracies of 1mm tolerance to a certain extent, this being 10m at a direct line of sight and up to 9m at an angle of roll of 5°. On the other hand, experiments involving pitch orientation, and yaw orientation did not meet the target accuracy of 1mm although the potential is there for smaller variations. This implied that the environment of which the transducers were in is vital to the degree of accuracy in distance measurement. Factors like line of sight between the transducers, intensity of ultrasound waves reaching the receiver, surrounding objects scattering the ultrasonic waves and interference from background noises may have affected the accuracy. A series of recommendations such as adding more parameters, conducting an outdoor experiment, a rail construction for movement of the tripods and experiments to attain optimal accuracy through a test between various transducers is suggested to further improve the study and for further exploration into the investigation of ultrasonic waves in distance measurement.Bachelor of Engineering (Mechanical Engineering

Enhancement of guided wave tomography for pipelines via improved transduction and signal deconvolution

Structural health monitoring (SHM) as opposed to conventional NDT methods involve the placement of permanent sensors and improve the reliability, cost efficiency and allows for continuous monitoring of non-uniform degradation. SHM monitoring can be catergorised into local or area monitoring but area monitoring has the benefit of providing a better baseline to assess the structural integrity of the pipeline in cases where critical parts are unknown because local monitoring does not provide enough of a representation to assess the integrity of the pipeline in its entirety. In area monitoring SHM, methods such as isual or thermal cameras are limited to surface breaking defects which are unable to quantify thickness from the inner pipe wall. Vibration techniques are a possible method although they are insensitive. This leaves acoustic emission (AE) or guided waves (GWs). However, AE requires continuous monitoring without interruption due to the nature of the defect propogation that is random and irreversible. This has implications on battery life and therefore the use of GWs provide a more suitable approach. Guided Waves (GWs) are bulk ultrasonic waves that interact with the boundaries of the structural wall and travel along the length of the structure. Most cases of GWs are confined to the low frequency range, where attenuation is low, allowing long sections of structures, e.g. pipelines to be screened. Although this method allows a quick assessment of a large area with defects, it is difficult to obtain the information on the size of the defect. Alternatively, a pitch-catch arrangement between two arrays of transducers, can be combined with tomographic principles, over a shorter distance, to provide more accurate sizing of defects. This concept, referred to as GW tomography (GWT), and still poses challenges for implementation in industry. The strong attenuation of fundamental modes in liquid loaded pipelines and the need to use voltage due to the intrinsic safety of operation around flammable pipelines have significant implications on the need for an improve Signal to Noise Ratio (SNR). To increase the Signal to Noise Ratio (SNR) and increase the effective distance between arrays, stacking of PZT discs are investigated and the parameters investigated to optimize the design are the mode amplitude, bandwidth, and mode purity. It was observed that the designed transducer with 10 PZTs stacked provides the optimum central frequency, nearest to "0.5 MHz∙mm" for GWT applications. However, the bandwidth decreases with increasing height of the stack. This drop in bandwidth with increasing number of PZTs stacked is compensated for by the addition of an Alumina composite backing mass. While increasing mode amplitude provides the possibility of using a lower voltage of excitation, a deconvolution technique using a Linear Frequency Modulated (LFM) signal is investigated to improve the SNR. The technique involves excitation of an LFM signal and deconvolution of the response to a toneburst. While this method has been previously used to optimize the number of cycles and frequency of tonebursts used, the application here is to reduce the voltage. During this study however, a trend of increasing input SNR with a plateauing output SNR is discovered. This is achieved by using the inherent convolution of a rectangular filter with the chirp frequency response. It was found that as the input SNR of the excited LFM signal increases, the noise after deconvolution (attributed only to the ringing effect) increases with the increased signal amplitude, resulting in an unchanging SNR. This area can be used to lower voltage while maintaining SNR. Finally, this thesis discusses the reliability and integrity of the application of the designed stacked transducer and lowering of voltage through deconvolution in an on-site application to validate the findings. Full Waveform Inversion (FWI) based GWT is used to provide a reconstruction of measured signals and defects on the gas pipeline were monitored for a period of 5 months. A simple statistical model is then incorporated to monitor the growth of selected defects beyond the 5-month period to predict the possible failure or when intervention techniques such as lowering of pipeline pressure is needed to extend the life of the pipeline.Doctor of Philosoph

On-line corrosion monitoring of plate structures based on guided wave tomography using piezoelectric sensors

Corrosion is a major safety and economic concern to various industries. In this paper, a novel ultrasonic guided wave tomography (GWT) system based on self-designed piezoelectric sensors is presented for on-line corrosion monitoring of large plate-like structures. Accurate thickness reconstruction of corrosion damages is achieved by using the dispersive regimes of selected guided waves and a reconstruction algorithm based on full waveform inversion (FWI). The system makes use of an array of miniaturised piezoelectric transducers that are capable of exciting and receiving highly dispersive A0 Lamb wave mode at low frequencies. The scattering from transducer array has been found to have a small effect on the thickness reconstruction. The efficiency and the accuracy of the new system have been demonstrated through continuous forced corrosion experiments. The FWI reconstructed thicknesses show good agreement with analytical predictions obtained by Faraday’s law and laser measurements, and more importantly, the thickness images closely resemble the actual corrosion sites

On-Line Corrosion Monitoring of Plate Structures Based on Guided Wave Tomography Using Piezoelectric Sensors

Corrosion is a major safety and economic concern to various industries. In this paper, a novel ultrasonic guided wave tomography (GWT) system based on self-designed piezoelectric sensors is presented for on-line corrosion monitoring of large plate-like structures. Accurate thickness reconstruction of corrosion damages is achieved by using the dispersive regimes of selected guided waves and a reconstruction algorithm based on full waveform inversion (FWI). The system makes use of an array of miniaturised piezoelectric transducers that are capable of exciting and receiving highly dispersive A0 Lamb wave mode at low frequencies. The scattering from transducer array has been found to have a small effect on the thickness reconstruction. The efficiency and the accuracy of the new system have been demonstrated through continuous forced corrosion experiments. The FWI reconstructed thicknesses show good agreement with analytical predictions obtained by Faraday’s law and laser measurements, and more importantly, the thickness images closely resemble the actual corrosion sites.NRF (Natl Research Foundation, S’pore)Published versio