321 results found
Yang S, Kiziroglou M, Yeatman E, et al., 2021, Passive acoustic transducer as a fluid flow sensor, IEEE Sensors Conference, Publisher: IEEE
Autonomy and minimal disruption are key desirable features for sensors to be deployed in medical, industrial, vehicle and infrastructure monitoring systems. Using a passive structure to transduce the quantity of interest into an acoustic or electromagnetic wave could offer an attractive solution for remote sensing, lifting the requirements of installing active materials, electronics, and power sources in remote, inaccessible, sensitive, or harsh environment locations. Here, we report a simple cavity and ball structure that transduces fluid flow through a pipe into an acoustic signal. A microphone on the outside wall of the pipe records the intensity and arrival rate of the sound pulses generated by collisions between the ball and the cavity walls. Using this approach external measurement of flow is demonstrated with adequate repeatability before any acoustic signal processing. This result is expected to open the way to the implementation of passive, remotely readable sensors for fluid flow and other fluid properties of interest.
Kim J, Yeatman E, Thompson A, 2021, Plasmonic optical fiber for bacteria manipulation—characterization and visualization of accumulation behavior under plasmo-thermal trapping, Biomedical Optics Express, Vol: 12, Pages: 3917-3933, ISSN: 2156-7085
In this article, we demonstrate a plasmo-thermal bacterial accumulation effect usinga miniature plasmonic optical fiber. Combined action of far-field convection and a near-fieldtrapping force (referred to as thermophoresis)—induced by highly localized plasmonicheating—enabled large-area accumulation of Escherichia coli. The estimated thermophoretictrapping force agreed with previous reports, and we applied speckle imaging analysis to mapthe in-plane bacterial velocities over large areas. This is the first time that spatial mapping ofbacterial velocities has been achieved in this setting. Thus, this analysis technique providesopportunities to better understand this phenomenon and to drive it towards in vivo applications.
Kassanos P, Yang GZ, Yeatman E, 2021, An Interdigital Strain Sensor through Laser Carbonization of PI and PDMS Transfer
Additive methods using inks have attracted significant attention for printing sensors. Laser carbonization of polyimide is an ink-less alternative. In this paper laser carbonization and transfer to polydimethylsiloxane (PDMS) are used for the realization of interdigital electrode-based impedance strain sensors. These were fabricated employing high-resolution laser engraver optics and are characterized under mechanical deformations with an impedance analyzer to assess their sensitivity. The sensors achieved appreciable strain sensitivities (~1%/N) that improve with increasing excitation frequency (500 Hz to 50 kHz), demonstrating the applicability of the sensor and the fabrication process for strain sensing.
Hu M, Kassanos P, Keshavarz M, et al., 2021, Electrical and Mechanical Characterization of Carbon-Based Elastomeric Composites for Printed Sensors and Electronics
Printing technologies have attracted significant interest in recent years, particularly for the development of flexible and stretchable electronics and sensors. Conductive elastomeric composites are a popular choice for these new generations of devices. This paper examines the electrical and mechanical properties of elastomeric composites of polydimethylsiloxane (PDMS), an insulating elastomer, with carbon-based fillers (graphite powder and various types of carbon black, CB), as a function of their composition. The results can direct the choice of material composition to address specific device and application requirements. Molding and stencil printing are used to demonstrate their use.
Kiziroglou ME, Wright SW, Yeatman EM, 2021, Power supply based on inductive harvesting from structural currents, IEEE Internet of Things Journal, ISSN: 2327-4662
Monitoring infrastructure offers functional optimisation, lower maintenance cost, security, stability and data analysis benefits. Sensor nodes require some level of energy autonomy for reliable and cost-effective operation, and energy harvesting methods have been developed in the last two decades for this purpose. Here, a power supply that collects, stores and delivers regulated power from the stray magnetic field of currentcarrying structures is presented. In cm-scale structures the skin effect concentrates current at edges at frequencies even below 1 kHz. A coil-core inductive transducer is designed. A fluxfunnelling soft magnetic core shape is used, multiplying power density by the square of funnelling ratio. A power management circuit combining reactance cancellation, voltage doubling, rectification, super-capacitor storage and switched inductor voltage boosting and regulation is introduced. The power supply is characterised in house and on a full-size industrial setup, demonstrating a power reception density of 0.36 mW/cm3, 0.54 mW/cm3 and 0.73 mW/cm3 from a 25 A RMS structural current at 360 Hz, 500 Hz and 800 Hz respectively, corresponding to the frequency range of aircraft currents. The regulated output is tested under various loads and cold starting is demonstrated. The introduced method may enable power autonomy to wireless sensors deployed in current-carrying infrastructure.
Fu H, Mei X, Yurchenko D, et al., 2021, Rotational energy harvesting for self-powered sensing, JOULE, Vol: 5, Pages: 1074-1118, ISSN: 2542-4351
Barbot A, Wales D, Yeatman E, et al., 2021, Microfluidics at fibre tip for nanolitre delivery and sampling, Advanced Science, Vol: 8, Pages: 1-10, ISSN: 2198-3844
Delivery and sampling nanolitre volumes of liquid can benefit new invasive surgical procedures.However, the dead volume and difficulty in generating constant pressure flow limits the use of small tubes such as capillaries.This work demonstrates sub-millimetre microfluidic chips assembled directly on the tip of a bundle of two hydrophobic coated 100 μm capillaries to deliver nanolitre droplets in liquid environments.Droplets are created in a specially designed nanopipette and propelled by gas through the capillary to the microfluidic chip where a passive valve mechanism separates liquid from gas, allowing their delivery.By adjusting the driving pressure and microfluidic geometry we demonstrate both partial and full delivery of 10 nanolitre droplets with 0.4 nanolitre maximum error, as well as sampling from the environment.This system will enable drug delivery and sampling with minimally invasive probes, facilitating continuous liquid biopsy for disease monitoring and in-vivo drug screening.
Sensor installation on water infrastructure is challenging due to requirements for service interruption, specialised personnel, regulations and reliability as well as the resultant high costs. Here, a minimally invasive installation method is introduced based on hot-tapping and immersion of a sensor probe. A modular architecture is developed that enables the use of interchangeable multi-sensor probes, non-specialist installation and servicing, low-power operation and configurable sensing and connectivity. A prototype implementation with a temperature, pressure, conductivity and flow multi-sensor probe is presented and tested on an evaluation rig. This paper demonstrates simple installation, reliable and accurate sensing capability as well as remote data acquisition. The demonstrated minimally invasive multi-sensor probes provide an opportunity for the deployment of water quality sensors that typically require immersion such as pH and spectroscopic composition analysis. This design allows dynamic deployment on existing water infrastructure with expandable sensing capability and minimal interruption, which can be key to addressing important sensing parameters such as optimal sensor network density and topology.
Lan L, Polonelli T, Qin Y, et al., 2020, An induction-based localisation technique for wirelessly charged drones, Pages: 275-277
This manuscript proposes a technique to use an inductive power transfer system to perform last-stage localisation of drones for tracking and automated landing. This system is proposed to assist the final stage of landing by solely making use of the inductive charger and avoid using vision or other external sensors which would increase cost and complexity.The simplicity of the proposed method can help widen the practical implementation of automated drones. This proposed method is demonstrated with a high frequency (6.78 MHz) inductive charging system that can deliver up to 100 W of power to a DJI M100 drone when it lands at any position on the designed one-meter diameter charging pad.
Pandiyan A, Boyle D, Kiziroglou M, et al., 2020, Optimal dynamic recharge scheduling for two stage wireless power transfer, IEEE Transactions on Industrial Informatics, Vol: 17, Pages: 5719-5729, ISSN: 1551-3203
Many Industrial Internet of Things applications require autonomous operation and incorporate devices in inaccessible locations. Recent advances in wireless power transfer (WPT) and autonomous vehicle technologies, in combination, have the potential to solve a number of residual problems concerning the maintenance of, and data collection from embedded devices. Equipping inexpensive unmanned aerial vehicles (UAV) and embedded devices with subsystems to facilitate WPT allows a UAV to become a viable mobile power delivery vehicle (PDV) and data collection agent. A key challenge is therefore to ensure that a PDV can optimally schedule power delivery across the network, such that it is as reliable and resource efficient as possible. To achieve this and out-perform naive on-demand recharging strategies, we propose a two-stage wireless power network (WPN) approach in which a large network of devices may be grouped into small clusters, where packets of energy inductively delivered to each cluster by the PDV are acoustically distributed to devices within the cluster. We describe a novel dynamic recharge scheduling algorithm that combines genetic weighted clustering with nearest neighbour search to jointly minimize PDV travel distance and WPT losses. The efficacy and performance of the algorithm are evaluated in simulation using experimentally derived traces, and the algorithm is shown to achieve 90% throughput for large, dense networks.
Li B, Tan H, Jenkins D, et al., 2020, Clinical detection of neurodegenerative blood biomarkers using graphene immunosensor, Carbon, Vol: 168, Pages: 144-162, ISSN: 0008-6223
Accurate detection of blood biomarkers related to neurodegenerative diseases could provide a shortcut to identifying early stage patients before the onset of symptoms. The specificity, selectivity and operational requirements of the current technologies, however, preclude their use in the primary clinical setting for early detection. Graphene, an emerging 2D nanomaterial, is a promising candidate for biosensing which has the potential to meet the performance requirements and enable cost-effective, portable and rapid diagnosis. In this review, we compare graphene-based immunosensing technologies with conventional enzyme-linked immunosorbent assays and cutting-edge single molecule array techniques for the detection of blood-based neurodegenerative biomarkers. We cover the progress in electrical, electrochemical and optical graphene-based immunosensors and outline the barriers that slow or prevent the adoption of this emerging technology in primary clinical settings. We also highlight the possible solutions to overcome these barriers with an outlook on the future of the promising, graphene immunosensor technology.
Liu H, Fu H, Sun L, et al., 2020, Hybrid energy harvesting technology: From materials, structural design, system integration to applications, Renewable and Sustainable Energy Reviews, Pages: 110473-110473, ISSN: 1364-0321
Lombardi G, Lallart M, Kiziroglou M, et al., 2020, A piezoelectric self-powered active interface for AC/DC power conversion improvement of electromagnetic energy harvesting, Smart Materials and Structures, Vol: 29, ISSN: 0964-1726
In the framework of hybrid energy harvesting for scavenging ambient motion, this paper proposes a cooperative piezoelectricelectromagnetic energy harvesting system to harvest rotational energy. In particular, while the actual process of harvesting energy is accomplished by the electromagnetic device, the piezoelectric element is used for improving the AC/DC conversion efficiency of the former. To do so, a half wave voltage doubler using MOSFETs driven by the piezoelement is employed. The low voltage output (order of magnitude of mV) of the electromagnetic system and the low conversion abilities of the piezoelectric transducer in the proposed mechanical structure justifies the motivation behind this work. Simulations followed by experimental validations are exposed and discussed, highlighting the improvement of energy conversion efficiency of an electromagnetic transducer, giving a power gain of 27 with respect to the DC power obtained with standard silicon diodes.
Kiziroglou ME, Wright SW, Yeatman EM, 2020, Coil and core design for inductive energy receivers, Sensors and Actuators A: Physical, Vol: 313, Pages: 1-9, ISSN: 0924-4247
The design of coil/core transducers is important for maximizing the power density of inductive energy receivers for both inductive energy harvesting and power transfer. In this work, we present a study of core and coil performance, based on a simulated flux distribution corresponding to aircraft applications. The use of funnel-shaped soft magnetic cores boosts magnetic flux density by flux concentration and allows the use of a smaller diameter coil. This reduces the transducer mass as well as the coil resistance (RCOIL), thereby increasing the available power density. Analysis and simulation shows a fifty-fold power density increase from moderate funneling and another two-fold increase by coil size optimization. Results are compared with experimental measurements which demonstrate a 31 μW/g power density from alternating environmental magnetic fields in the 10 μT/360 Hz range.
Polonelli T, Qin Y, Yeatman E, et al., 2020, A flexible, low-power platform for UAV-based data collection from remote sensors, IEEE Access, Vol: 8, Pages: 164775-164785, ISSN: 2169-3536
This article presents the design and characterisation of a new low-power hardware platform to integrate unmanned aerial vehicle and wireless sensor technologies. In combination, these technologies can overcome data collection and maintenance problems of in situ monitoring in remote and extreme environments. Precision localisation in support of maximum efficiency mid-range inductive power transfer when recharging devices and increased throughput between drone and device are needed for data intensive monitoring applications, and to balance proximity time for devices powered by supercapacitors that recharge in seconds. The platform described in this article incorporates ultra-wideband technology to achieve high-performance ranging and high data throughput. It enables the development of a new localisation system that is experimentally shown to improve accuracy by around two orders of magnitude to 10 cm with respect to GNSS and achieves almost 6 Mbps throughput in both lab and field conditions. These results are supported by extensive modelling and analysis. The platform is designed for application flexibility, and therefore includes a wide range of sensors and expansion possibilities, with source code for two applications made immediately available as part of a open source project to support research and development in this new area.
Shi M, Holmes A, Yeatman E, 2020, Piezoelectric wind velocity sensor based on the variation of galloping frequency with drag force, Applied Physics Letters, Vol: 116, ISSN: 0003-6951
In this paper, we demonstrate a miniature energy harvesting wind velocity sensor of simple, low-cost construction, based on a single-degree-of-freedom galloping structure. The sensor consists of a prismatic bluff body with a triangular cross section attached to the free end of acantilever incorporating a commercial polyvinylidene fluoride piezoelectric film. In the wind, the bluff body causes vibration of the cantileverbased on galloping, and the piezoelectric film converts the vibration energy into an electrical signal. We have observed a negative correlationbetween the wind velocity and the vibration frequency, and we demonstrate that this relationship can be used to detect wind velocity directlywith useful accuracy. A simple theoretical model indicates that the frequency shift can be accounted for by the effect of the axial loading dueto form drag. The model shows close agreement with the experimental results. In wind tunnel tests, a prototype wind velocity sensor basedon this principle could measure wind velocities from 4.45 to 10 m/s, with the measured velocity typically being within 4% of the referencevalue obtained using a Pitot tube.
Kiziroglou ME, Wright SW, Yeatman EM, 2020, Shaped coil-core design for inductive energy collectors, 19th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (Power MEMS), Publisher: IEEE, Pages: 1-4
Coil design is important for maximizing power density in inductive energy harvesting as well as in inductive power transfer. In this work, we present a study of coil performance, based on simulated flux distributions corresponding to a real aircraft application case. The use of funnel-shaped soft magnetic cores boosts magnetic flux density by flux concentration and allows the use of a smaller diameter coil. This reduces the transducer mass as well as the coil resistance (R COIL ), thereby increasing the power density. Analysis and simulation shows a fifty-fold power density increase from moderate funneling and another two-fold increase by coil size optimization. Results are compared with experimental measurements presented in  which demonstrate a 36μW/g(106μW/cm 3 ) power density from alternating environmental magnetic fields in the 10μT/300 Hz range.
Many motion-active materials have recently emerged, with new methods of integration into actuator components and systems-on-chip. Along with established microprocessors, interconnectivity capabilities and emerging powering methods, they offer a unique opportunity for the development of interactive millimeter and micrometer scale systems with combined sensing and actuating capabilities. The amplification of nanoscale material motion to a functional range is a key requirement for motion interaction and practical applications, including medical micro-robotics, micro-vehicles and micro-motion energy harvesting. Motion amplification concepts include various types of leverage, flextensional mechanisms, unimorphs, micro-walking /micro-motor systems, and structural resonance. A review of the research state-of-art and product availability shows that the available mechanisms offer a motion gain in the range of 10. The limiting factor is the aspect ratio of the moving structure that is achievable in the microscale. Flexures offer high gains because they allow the application of input displacement in the close vicinity of an effective pivotal point. They also involve simple and monolithic fabrication methods allowing combination of multiple amplification stages. Currently, commercially available motion amplifiers can provide strokes as high as 2% of their size. The combination of high-force piezoelectric stacks or unimorph beams with compliant structure optimization methods is expected to make available a new class of high-performance motion translators for microsystems.
Kang M, Yeatman E, 2020, Coupling of piezo- and pyro-electric effects in miniature thermal energy harvesters, Applied Energy, Vol: 262, ISSN: 0306-2619
Thermal energy harvesting from ambient heat into electricity is of interest due to its wide potential applicability. This paper demonstrates a moving beam thermal energy harvesting mechanism exploiting both pyro- and piezo-electric effects simultaneously, for use adjacent to a heat source with small temperature variations at low frequency (below 0.1 Hz). For the first time, the relative contributions of these two mechanisms in such a device is established both theoretically and experimentally, and a dynamic model is provided. The relative phase of the contributed currents is shown to be a critical factor, and methods are introduced to optimise this phase relationship, particularly by selection of the mechanical configuration. The reported prototype achieves around 0.4 for a temperature difference of around 15 K at frequency 0.02 Hz with an optimal condition in the fixed-fixed configuration about 90% above the fixed-free end configuration.
Pandiyan AYS, Kiziroglou ME, Boyle DE, et al., 2020, Optimal Energy Management of Two Stage Energy Distribution Systems Using Clustering Algorithm, 19th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (Power MEMS), Publisher: IEEE
Pandiyan AYS, La Rosa R, Kiziroglou ME, et al., 2020, Understanding Far Field Ultrasonic Power Transmission for Automobile Sensor Networks in Free Space, 19th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (Power MEMS), Publisher: IEEE
Fu H, Song W, Qin Y, et al., 2020, Broadband Vibration Energy Harvesting from Underground Trains for Self-Powered Condition Monitoring, 19th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (Power MEMS), Publisher: IEEE
Lombardi G, Lallart M, Kiziroglou M, et al., 2020, AC/DC power conversion improvement of rotational electromagnetic energy harvesting using piezoelectric elements for active rectification, 19th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications (Power MEMS), Publisher: IEEE
Qin Y, Boyle D, Yeatman E, 2019, Efficient and reliable aerial communication with wireless sensors, IEEE Internet of Things Journal, Vol: 6, Pages: 9000-9011, ISSN: 2327-4662
This paper describes the design, implementation and evaluation of a first of its kind cross-layer protocol for wireless communication between flying agents and terrestrial wireless sensors. The protocol is composed of three layers: a new application layer built upon a modified implementation of ContikiMAC over the IEEE 802.15.4 2.4 GHz physical layer. The experimental evaluation shows the protocol to have excellent energy efficiency, low latency and high reliability-approaching 100% for certain parameter settings and operational conditions. The effects of speed, altitude, and direction of approach are also experimentally evaluated, demonstrating that it is of critical importance to take these into account when planning mobile aerial data collection campaigns.
Fu H, Yeatman E, 2019, Rotational energy harvesting using bi-stability and frequency up-conversion for low-power sensing applications: Theoretical modelling and experimental validation., Mechanical Systems and Signal Processing, Vol: 125, Pages: 229-244, ISSN: 0888-3270
Abstract Kinetic energy harvesting has drawn great attention in the past decade, but low-frequency and broadband operation is still a big issue which impedes this technology to be widely deployed in low-power Internet of Things applications. In this paper, theoretical modelling and experimental validation of a rotational harvester with bi-stability and frequency up-conversion is presented for harnessing low-frequency kinetic energy with a wide bandwidth. Piezoelectric transduction was adopted to convert the rotational kinetic energy into electricity. Distributed-parameter modelling was employed for analyzing the electromechanical dynamics of the bistable piezoelectric beam. Bistable and frequency up-converting behaviours were considered in the theoretical model by introducing two external input magnetic forces. Different oscillating modes were analyzed, showing the variation of power generation capability under different modes, and the advantage of operating in the periodic double-well mode. From the potential well study, we got a conclusion that for the same input magnetic force, periodic double-well mode is capable of achieving a larger vibration amplitude compared to a harvester without bi-stability. Asymmetric potential well shapes were investigated. This asymmetric shape provides a way to stabilize the initiation position of the beam for each plucking cycle, and eventually to stabilized the output. Key design factors to control the oscillating modes were studied, providing a guideline for future design. An experimental study was conducted to verify the theoretical results. A close match was achieved. This bistable harvester demonstrated a significant improvement (up to 2 × ) compared to a harvester without bi-stability over a wide bandwidth (from 1 to 11 Hz) at low frequencies, when operating in the periodic double-well mode. This paper presents a detailed theoretical model and in-depth analysis of a bistable frequency up-converting harvester, providing a
Wright S, Kiziroglou M, Spasic S, et al., 2019, Inductive energy harvesting from current-carrying structures, IEEE Sensors Letters, Vol: 3, ISSN: 2475-1472
This article introduces an inductive method for harvesting energy from current-carrying structures. Numerical simulation of a structural beam shows that the skin effect can lead to significant current concentration at edges, providing a five-fold power benefit at such locations, even at frequencies below 1 kHz. The use of a rectangular ferrite core can provide a ×4 power density improvement. The adoption of funnel-like core shapes allows the reduction of core mass and coil frame size, leading to significant further power density enhancement. Magnetic field simulation and coil analysis demonstrate a power density increase of ×49 by ferrite funnels, in comparison to a coreless coil. Experimental results demonstrate rectified power over 1 mW delivered to a storage capacitor, from a 40 × 20 × 2 mm core-and-coil, in the vicinity of a spatially distributed 20 A current at 800 Hz. Rectification and impedance matching are studied experimentally using a voltage doubler circuit with input capacitor tuning to counteract the coil reactance. Experimental results from a spatially distributed 30 A current at 300 Hz and a 1:7 funnel core demonstrate power density of 36 μ W/g (103 μ W/cm 3 ), opening up the way to noninvasive inductive powering of systems in the vicinity of current-carrying structures.
Boyle DE, Wright SW, Kiziroglou ME, et al., 2019, Inductive Power Delivery with Acoustic Distribution to Wireless Sensors, Pages: 202-204
This paper proposes a new way to energize wireless sensors combining inductive power transfer with onward acoustic power distribution. Recent results showing inductive transfer of tens of watts from unmanned aerial vehicles to wireless sensors, in addition to acoustic propagation providing useful levels of transduced power, i.e. tens of mW, can be combined to form a hybrid wireless power transfer system for deeply embedded wireless sensors. Particular emphasis is placed on rectification efficiency for the acoustic receiver, finding that a minimum of 400 μW (for given parameters) are required to avoid excessive rectification losses, which is significant considering the finite energy available from the intermediate energy store.
Fu H, Zhou S, Yeatman E, 2019, Exploring coupled electromechanical non-linearities for broadband energy harvesting from low-frequency rotational sources, Smart Materials and Structures, Vol: 28, ISSN: 0964-1726
This paper presents a methodology to effectively harness low-frequency broadband rotational energy using coupled electromechanical non-linearities. This design integrates bi-stability and a synchronized switch harvesting on inductor (SSHI) circuit into a frequency up-converting harvester. The bistable behaviour enables improved output power due to the increased vibration amplitude under the same input plucking force. The SSHI circuit exhibits enhanced conversion capability, contributing higher electrical damping which is ideal for frequency up-converting harvesters to alleviate output fluctuation at high frequencies. To study the coupled non-linear dynamics from both the mechanical (bi-stability) and electrical (SSHI) sides, a system-level theoretical model is, for the first time, established and numerically solved using Matlab/Simulink. System behaviours, which would not be able to obtain using circuit simulation methods, are studied for different operating frequencies and load resistances. To validate the theoretical analysis, this harvester was implemented and tested experimentally. A close match was obtained. From the experimental results, an enhanced output power (up to 525%), over a broad frequency range, was realized, compared to that of a harvester with neither bi-stability nor SSHI circuits.
Gramling HM, Towle CM, Desai SB, et al., 2019, Spatially Precise Transfer of Patterned Monolayer WS2 and MoS2 with Features Larger than 10(4) mu m(2) Directly from Multilayer Sources, ACS APPLIED ELECTRONIC MATERIALS, Vol: 1, Pages: 407-416, ISSN: 2637-6113
Kang M, Yeatman EM, 2019, Hybridized thermal energy harvesting mechanism, 18th International Conference on Micro and Nanotechnology for Power Generation and Energy Conversion Applications, Publisher: IOP PUBLISHING LTD, ISSN: 1742-6588
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.