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Group: Systems, Power and Energy
Speaker: Dr. Jahrul Alam, Associate Professor, Department of Mathematics and Statistics Memorial University, Canada
Date: 11 June, 2019
Time: 14:00 - 15:00
Location: James Watt South Building, Room 427A
Turbulence remains an unsolved problem, but can be described in terms of coherent
structures that cascade kinetic energy through a hierarchy of length scales. We need
to develop efficient and accurate turbulence models that can explain the role of
coherent structures in order to build better vehicles that travel through air or water,
to design more efficient wind turbines that extract clean energy from the atmosphere,
or to characterize dispersion of pollutants in cities. In particular, for large-scale wind
energy projects, it is important to understand how the efficiency of turbines is
decreased due to the complex interaction among turbines and atmospheric
turbulence, how the energy is entrained from the free atmosphere to the wind-farm,
and where the energy is dissipated. In this talk, I will discuss an LES approach to
illustrate the interaction between a field-scale wind-farm and atmospheric
turbulence. Using wind tunnel measurements for a scaled model wind-farm along
with “heuristic arguments”, I will demonstrate that the coherent structures play a
major role to entrain kinetic energy into the wind turbine array. I will also discuss
how the LES approach constructed for this research can be useful in other
applications of wall-bounded turbulence and reacting flows.
Zhiyuan Shen’s research interests lay in the areas of miniaturized transducers and metamaterials, which extend from artificial designs microfabricated using MEMS technologies to natural products like the ones found in insects and fishes. One of his major research focus is on piezoelectric material-based acoustic and ultrasonic transducers. He worked extensively on how to integrate the piezoelectric material into the MEMS process and how to optimize the transducers targeting for different application scenarios. Another his research focus is on the biomimetic methodology. He tried to explore the biomechanics of the structures and materials found in animals and accordingly fabricated new devices and materials mimicking the structures and functions of these natural products.
The presentation will explain some devices and materials studied by Zhiyuan Shen, which include: 1, a radial field piezoelectric diaphragm, with its application as an acoustic transducer and an energy harvester; 2, a piezoelectric thin film PLZT-based wireless accelerometer, with its application in mechanical vibrational monitoring; 3, aerosol spray direct-write piezoelectric polymer P(VDF/TrFE)-based Lamb-wave ultrasonic transducer arrays for aircraft plate parts non-destructive testing application; 4, fish lateral line neuromasts-inspired hair cell sensors and its application in intravenous tube flow rate monitoring; 5, biomechanics of moth scales and the acoustic camouflage effect of moth’s scaled wings.
Zhiyuan Shen received his B.E. and M.E., both in microelectronics and solid state electronics, respectively from the Harbin Institute of Technology (HIT, 2005) and the Xi’an Jiaotong University (XJTU, 2008) in China. He was awarded a Ph.D. in mechanical engineering from the Nanyang Technological University (NTU, Singapore, 2013) under Prof. Jianmin Miao. His thesis was on the experimental study of radial field piezoelectric MEMS transducers. He worked as a research staff in the Institute of Materials Research and Engineering (IMRE, A*STAR, Singapore, 2012-2014), participated in a few industrial projects on developing ultrasonic transducers for non-destructive testing. From 2015-2016 he worked as a postdoctoral associate at the Singapore-MIT Alliance for Research and Technology (SMART, Singapore) under the supervision of Professor Michael Triantafyllou on biomimetic hair cell flow rate sensor research. In 2016, Zhiyuan Shen joined the Univ. of Bristol in UK, studied the moth scale’s nanostructure and its acoustic camouflage effect under Dr. Marc Holderied, Prof. Bruce Drinkwater and Prof. Daniel Robert. Zhiyuan Shen is currently a Research Associate in the UltraSurge project, developing high power ultrasonic transducers for biomedical applications.
Superparamagnetic iron-oxide nanoparticles (SPIONs) are widely used as an MRI contrast agent in hospitals today. It has been discovered that these same SPIONs can be used as an ultrasonic contrast agent. When the SPIONs are subjected to an external, oscillating magnetic field this causes the SPIONs to vibrate. This in turn creates a vibration in the tissue in which they are embedded. This tissue vibration can be imaged using ultrasound, despite the SPIONs being far too small to resolve directly using ultrasound wave interactions. This technique is known as magneto-motive ultrasound (MMUS).
Microbubbles are another ultrasonic contrast agent. These are again too small to be resolvable using standard ultrasonic imaging, but bubble interactions with ultrasonic waves can be used to locate the microbubbles. Microbubbles can be further controlled if they have SPIONs embedded in their shells, making them responsive to magnetic fields. These magnetic microbubbles (SPION-MBs) have been studied in static magnetic fields for targeted drug delivery.
This research proposes the usage of SPION-MBs as a new contrast agent for MMUS. Modelling studies suggest that they will generate larger vibrations (x1.3) than SPIONs on their own allowing for improved sensitivity. The target is to create qualitative measurements of tissue stiffness in a form of elastography measurement. Controlled collapse of the microbubbles should also allow for transient elastography measurements. Once established, the approach offers significant future opportunities for therapy and enhanced diagnostic imaging, using a non-ionising technique, with the potential for in-surgery guidance.
Claire Thring achieved a first-class master’s degree in Physics from the University of Warwick, graduating in 2014, with a focus on modelling the ultrasonic characterisation of heel bone osteoporosis. Following this, she pursued a PhD in NDT, submitting her thesis in April 2018. Over the course of her PhD she authored three journal papers, two conference papers, and was awarded an R. W. B. Stephen’s Prize at the ICU 2017, Hawai’i. She taught electronics to the undergraduate Physics students, taught and marked maths support classes, and worked part time as a dance and fitness instructor throughout her PhD. She began work as a post-doctoral research assistant at the University of Glasgow in March 2018 working with Dr Helen Mulvana on the development of magneto-motive ultrasound contrast techniques funded by Cancer Research UK.
Novel ferroelectric materials: from materials design to realisation in a range of energy harvesting applications
Embedded sensor systems used in our daily lives are powered by batteries, which need to be recharged or replaced, thus pollute the environment once thrown away. One solution is to eliminate the battery and use energy harvesting instead by extracting energy from the surrounding environment and converting it into electrical energy. The environment offers several forms of energy to be converted, such as solar power, wind energy and vibrations. Here we focus on harvesting mechanical and thermal energy using ferroelectric materials.
Ferroelectric materials are an important class of electro-active dielectrics that exhibit high levels of polarisation, high permittivity, large electromechanical coupling, and a number of functional properties such as piezoelectric, pyroelectric, electro-caloric and electro-optic properties for applications related to sensors, actuators, energy harvesters, and transducers.
In this lecture I will present the key concepts behind the design of functionally graded novel ferroelectric materials in a range of energy harvesting systems, focusing on microstructural and compositional optimisation. I will introduce dielectrophoretically structured ceramic-polymer composites with outstanding sensing capabilities, screen printed large area flexible piezo devices and highly heterogeneous porous ceramics and composites fabricated using freeze casting. Addition of porosity provides beneficial effective properties for specific applications, such as strain energy harvesting as well as thermal energy recovery via pyroelectric effect for water splitting. I will also show case the potential of biocompatible ferroelectric materials for biomedical applications.
Dr Hamideh Khanbareh received her Cumlaude MEng degree in Aerospace Engineering from Delft University of Technology, Netherlands, in 2012. Her final project concerned fractal analysis of microstructures of ultra-high strength Aluminium alloys for aerospace applications. She then pursued her PhD in Novel Aerospace Materials group, at Delft University of Technology working on functionally graded ferroelectric ceramic-polymer composites. During her PhD she also worked as a visiting scientist at the Molecular Electronics Research Group at Max Planck Institute for Polymers (MPIP), in Mainz, Germany. In June 2016 she obtained her PhD degree from Delft University of Technology and subsequently was appointed as a Prize Fellow at the Materials and Structures Research Centre, within the Department of Mechanical Engineering at University of Bath, UK. Dr Khanbareh’s main research interests are in materials design, modelling, fabrication and application of piezo- and pyroelectrics in sensing and energy harvesting. Heterogeneous polymer-ceramic composites and porous ceramics, offering a wide range of compositional and microstructural design flexibility, are the target of her current research. Dr Khanbareh has a strong record of publications, authoring over 20 peer-reviewed journal papers and 10 conference papers. She has been a member of IOM3 Smart Materials & Systems Committee (SMASC), Institute of Electrical and Electronics Engineers (IEEE) Ferroelectrics as well as Royal Society of Chemistry and UK Society of Biomaterials.
Speaker 1 – Dr Xuan Li, an introductory talk
Abstract: Ultrasonic machining is to employ strong ultrasonic vibrations on the relative motion between a cutting tool and workpiece. Maintaining the vibro-impact response will ensure a great cutting force reduction during machining, therefore improve parts surface finish quality, produce shorter chips, reduce burr formation and reduce tool wear. UPCD project is to obtain rock core samples from the Mars sub-surface level for analysis, this project employs the Ultrasonic/Sonic Drill/Core (USDC) technology which converts high frequency ultrasonic energy to sonic energy via a chaotic motion of a free flying mass, therefore achieve effective blows for the corer to penetrate into rocks. Laser Ultrasonic Assisted Machining (LUAM) technology adopts both high power ultrasonic vibration and high power laser to assist machining process, the idea is to heat up the machining zone effectively and then apply high power ultrasonics, to accelerate the productivity and improve the quality. Due to the high cost of workpieces (most super alloys or metal matrix composites for aerospace structures), simulation process is crucial to optimize the parameters. Split Hopkinson Pressure Bar (SHPB) technology is used at 1st stage to study the flow stress-strain curves of the target workpiece materials, at various high strain rates, and high temperatures. For the miniature ultrasonic surgical device design, different solid geometry horns/tips were tested in combination with number of PZT rings for the Bolted Langevin-style Transducers (BLT) within a tight space design requirements, in order to explore the optimal shape and appropriate number of exciter units to maximize the delivered ultrasonic vibrations on the cutting tip. The research outcome provides the design benchmarks for the new UltraSurge project.
Bio: Xuan Li is the “returning” research associate at the University of Glasgow, working on the Ultrasurge project – Innovative Miniature Ultrasonic Surgical Devices. Xuan obtained his PhD in Mechanical and Manufacturing Engineering from Loughborough University, focused on resonant tracking system design and modelling on ultrasonic assisted machining applications. He then worked as a research associate on the ultrasonic planetary core drill (UPCD) project for 3 years in University of Glasgow. He had 1 year experience in designing miniature ultrasonic surgical device with Stryker. Prior to the start of the new UltraSurge project, he worked as a technical lead/research associate in the Advanced Manufacturing Research Centre (AMRC) with Boeing, University of Sheffield for more than 1 year. Xuan’s main research interests are high power ultrasound applications.
Speaker 2- Rebecca Cleary: ‘Ultrasonic Petrous Apex Surgery (UPAS)’
Abstract: High power ultrasonics has the potential to be used in the surgical treatment of the petrous apex. One of the most inaccessible locations of the skull, the petrous apex lies close to the ear and is an area where lesions, tumours and cysts can be found. Currently, there is not a practical technique for accessing the region. Interventions require an extended surgical approach commonly related to loss of hearing, balance, facial nerve function and in some cases morbidity. There is the potential to use a ‘keyhole’ approach which is safe and minimally invasive using a power navigated ultrasonic biopsy tool.
Bio: Rebecca is a post-doc leading the research of an Impact Acceleration Account (IAA) on high power ultrasonic needles capable of performing bone biopsies of the petrous apex. She achieved a MEng in Electrical & Electronic Engineering from the University of Strathclyde and is currently finalising her PhD thesis conducting with MIU on ultrasonic needle technology.
Our guest for this second event will be Dr Marilena Di Carlo from the University of Strathclyde who will give a presentation about Design of optimal and robust low-thrust trajectories for interplanetary missions. This topic is of particular interest because in recent years low-thrust propulsion has become a key technology for space exploration and its use has increased for both near-Earth and interplanetary missions. Low-thrust propulsion systems have indeed the potential to provide shorter flight times, smaller launch vehicles, and increased mass delivered to destination. The first part of the talk will introduce the computational tools developed at the University of Strathclyde to address this problem. The presentation will then focus on the design of low-thrust missions to different families of asteroids.
The schedule for this meeting is the following:
- 10.30 – 10.45: Space Engineering Meeting presentation and theme introduction
- 10:45 – 11:15: Guest presentation
- 11:15 – 12:00: Q&A and public discussion
Abstract: One of the emerging technologies in diagnostic medicine is a multi-modal endoscopic pill which, in addition to the already available visible light mode, includes ultrasound and auto-fluorescence sensing capabilities. A central issue with the more complex device development is additional area and power consumption (which also includes additional higher data processing and communication capabilities required). As the maximum size of the pill is constrained, the complexity of the overall design of a multimodal pill forces extreme area, efficiency and integration limitations on power management unit IC design. The PMU being developed is capable of regulating power supplied by batteries or wireless power transfer and reliably delivering it to pill systems ranging from low (1.8 V for amplification, processing etc.) to high (> 20 V for ultrasound and fluorescence) voltage applications. This work is currently focused on creating a voltage amplification circuit (charge-pump) for ultrasound modality. Future plans include developing front-end driving and sensing circuitry for the ultrasound application.
Bio: Bartas Abaravicius is a second year PhD student at the University of Glasgow, working in analog circuit design and focusing on power management and ultrasound sensing applications. Bartas has finished his MEng in Electronics and Electrical Engineering in the University of Glasgow. He was repulsed by the possibility of his effort and time going towards developing electronics for the sole purpose of consumer satisfaction and capitalist money hoarding of many and, as a result, has directed his effort to try to elevate suffering of some.
Abstract: Piezoelectric single crystals are emerging as materials with great potential for high-power industrial and underwater SONAR applications possessing large figures of merit, allowing novel transducer designs and exploiting higher energy density to give smaller, lighter devices. However, methods of growth result from experimentally developed specifications following an historical lack of theoretical input, which is essential to develop materials with enhanced properties. So, complete fundamental characterisation with foundation in applications is needed to realise the potential of piezocrystals. Relaxor-PT ferroelectric single crystals epitomise the performance of piezocrystals exhibiting ultrahigh piezoelectric coefficient d and electromechanical coupling k but low mechanical quality factor Qm. Energy density, usually quantified by k^2, concerns extractable work. However, k is specific to the vibrational mode and geometry. Whilst improved k may result from improved properties, the fundamental issue of why different modes/geometries have different values and how these scale needs to be addressed.
Bio: Nathan graduated from the University of Edinburgh in 2017 with an MPhys in theoretical physics. He is now a second year PhD student in MIU funded by Thales. His project is studying single crystal piezoelectric material for use in SONAR.
Outline: In this talk, an introduction to Sonar technology for underwater applications is given from the perspective of an Acoustics Engineer working at Thales. It maps the evolution of Sonar transducer design – starting from the atomic level fundamentals of piezoelectricity through to large scale operational hardware. This includes current research in collaboration with the University of Glasgow for future Sonar technology. There is also an overview of Thales, and information detailing possibilities to work with Thales, including the Thales Graduate Scheme.
Brief Biography: Hannah Rose works in the Acoustics and Materials team at Thales UK developing underwater transducers for Sonar, having joined the Thales engineering graduate scheme in 2012. She is also studying for a part-time PhD with the University of Glasgow supervised by Professor Sandy Cochran. This work researches the next generation of piezoelectric materials and how to use them in future Sonar devices. Hannah received her Masters in Physics with Honours Astrophysics from the University of Edinburgh in 2011.
Group: Systems, Power and Energy
Speaker: Dr Maya Thanou, Institute of Pharmaceutical Science, King’s College London
Date: 25 May, 2018
Time: 13:00 - 14:00
Location: Wolfson Building, Seminar Room 3 (Gannochy)
We have prepared and developed thermosensitive liposomes that can be tracked in the body using imaging. Their drug release can be activated by the applied hyperthermia induced by Focused Ultrasound (FUS). We have labelled the liposomes using newly synthesized lipids that can be used for MRI and NIRF imaging. We have prepared and characterised the iTSLs (imageable thermosensitive liposomes) for optimum contrast enhancement and thermally triggered release in combination with a FUS treatments regimen (thermal dosing). Labeling of liposomes for imaging can provide substantial information of the mechanism of tumor uptake (post injection) with and/or without the treatment of FUS. We prepared iTSLs to encapsulate the anticancer drug topotecan (Hycamtin®), a chemotherapeutic agent which when released in vivo can be monitored by its intrinsic drug fluorescence. We have optimized drug encapsulation for maximum fluorescence signal difference (before /after release) for both in vitro and in vivo. FUS (Phillips) was applied using temperature feedback via subcutaneously placed fine-wire thermocouples to maintain hyperthermic temperatures. Imaging was performed using multispectral analysis bioimaging (Maestro EX) following the emission of the NIRF lipid and topotecan. FUS was applied using imaging as guidance. Imaging and tumor growth results indicated that FUS applications significantly improve liposome distribution in the tumour potentially by assisting nanoparticle extravasation. Hyperthermia triggered thermal drug release in tumors as indicated by Imaging. MRI confirmed observations obtained with NIRF imaging. iTSL nanoparticles is a theranostic tool for precise tumor drug delivery.