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James Ransley Cv Linked In James Ransley Cv Linked In Document Transcript

  • James Ransley A Cambridge trained physicist with experience in microelectromechanical systems currently working with Xaar’s acoustic inkjet technology. I have a demonstrated track record of innovation, a strong background in analytic and numerical modelling of complex systems and experience in working across disciplines both in academia and in industry. I am looking to move to a role that will enable me to continue to work with the physics that I have always enjoyed. Education 1999-2003 Darwin College, Cambridge University, UK PhD Materials Science (awarded July 2004) The properties of grain boundaries in YBa2Cu3O7-δ. (Supervisor: Prof. J. E. Evetts) 1995-1999 Churchill College, Cambridge University, UK BA Hons Natural Sciences (Physics) Class 2:1 Earlier courses included mathematics, geology and materials science. 1988-1995 Lord Wandsworth College, Hook, Hampshire, UK 1995 A-Levels: Maths (A), Adv. Maths (A), Physics (A), Biology (A) 1993 10 GCSEs (including English language and French): all grade A Employment 2008-2010 Xaar PLC, Science Park, Cambridge, United Kingdom Design / Applications Engineer (Current Position) 2004-2008 Nanoscience Centre, Engineering Department, Cambridge University, UK Research Associate developing micromechanical sensors 2004-2006 MEMs technologies for the label free detection of biochemical molecules 2006-2007 Underground M3 Project 2007-2008 Enhanced Silicon Microresonator Oscillators (Depletion Layer Actuators) Key Skills Applying varied physics to practical devices: Modelling dynamic fluid flow through print heads (laminar flow and water hammer), thermal modelling of heat dissipation in devices, modelling electrostatically actuated devices, application of semiconductor device physics to produce a mechanical actuator. Modelling of actuator coupling to resonant systems. Systems approach for complex systems: using equivalent circuits for linear systems coupled to electronics. Track record of innovation & creativity. Modelling tools: Strong record of analytic & numerical modelling (see publication record) with work in diverse fields from tunnelling models for the complex band structures of the cuprates to modelling pressure transients in print head back ends. Use of the Mathematica software package for detailed analytic & numerical modelling. Use of MATLAB for numerical modelling & data analysis. Finite element modelling within the COMSOL Multiphysics software package. Use of SPICE circuit analysis tools for developing system models. Precision measurements & product test against specification: Experience of precision AC and DC device electrical characterisation, including use of network analysers. Thermal measurements (thermocouples/thermal cameras). Measurement of mechanical displacement with optical levers. Strain measurement. Liquid pressure measurements employing pressure transmitters. Inkjet product test: drop landing accuracy, drop volume, drop velocity, pressure/temperature/voltage window of operation etc. Data acquisition & processing with Labview and National Instruments Hardware. Data analysis with Labview, MATLAB and Minitab statistical software.
  • Product Design & Manufacture: Strong background in MEMs device design and manufacture (including extensive clean room experience). Experience with piezoelectric devices & manufacturing processes. Familiarity with other mass production technologies (e.g. injection moulding, casting etc.). Experience of design for manufacture. Trained user of Solidworks 3D CAD tool. Recently attended Cambridge University IFM courses on new product development and project management. Written and Verbal Communication: Thesis commended for clarity of presentation and writing. Papers written in top journals (see attached publication list). Co-wrote successful UK government grant (EPSRC grant: EP/F009127/1). Invited to referee papers in Sensors and Actuators and for the Journal of Imaging Science and Technology. Talks & invited talks at national and international conferences. Opened oral session at Transducers ’07 (largest MEMs conference in 2007 with several thousand participants). Team work / Leadership / Mentoring: Demonstrated ability to work effectively with interdisciplinary teams across discipline boundaries. Worked successfully on projects across fields including: biotechnology, electronic engineering, civil engineering, theory of condensed matter, mechanical engineering, manufacturing engineering, test engineering & software development. Taught physics within the Cambridge University supervision system. Organised Xaar’s company seminar program and taught internal course on FEA. Conceived and managed 3 MPhil student projects in Cambridge University. Cross cultural awareness through role overseeing Cambridge University’s international student welcome programme as a graduate student (2001). President of a Cambridge University society (Christian Graduate Society - 2002/2003). Research and Development Record Research and Development at Xaar PLC Played a key technical role in the development of the Xaar electron print head (shown on left) – which is currently being launched with OEM distributors. Performed initial development of company strategy to drive print heads which is now being rolled out across all product lines. Developed system models for print head dampers to control pressure in back end of head. Worked on design of print head back ends including micro-fluidics and thermal performance. Extensive involvement in design work for Xaar’s platform 3 product range including exploring additional products to compliment the successful 1001 head. Part of the team exploring options for Xaar’s next product platform, which will be MEMs based. Invented a new actuator technology that is currently being considered for patenting. Depletion Layer Actuators Invented & patented [11] an actuator that is highly compatible with 3.5 standard semiconductor processing technologies. Co-wrote grant to 3 explore the technology (EPSRC grant EP/F009127/1). Amplitude (nm) 2.5 2 Demonstrated that the actuator performs as predicted by fabricating 1.5 Shottky diodes on AFM cantilevers and driving them at resonance 1 (see graph on the left). This work was published in Applied Physics 0.5 Letters [2] and was presented as the opening talk in the actuators 0 session at Transducers 2007 [3]. Researchers at Cornell have 5 10 15 20 Frequency (kHz) recently used these actuators to efficiently drive silicon MEMs resonators at 3GHz.
  • Underground Infrastructure Monitoring Played a key role at the start of a multidisciplinary project to install wireless instrumentation in underground railway systems across Europe (including the London Underground). Performed initial design work on MEMs strain sensors (see left). Involved in process design for producing narrow-gap tuning fork strain sensors [1]. Initiated a project to investigate a new method to harvest electromagnetic energy from ambient vibrations. Developed model to predict the performance of energy harvesting devices with arbitrary driving. Comparison of SU8 and Silicon Cantilever Sensors By applying a functional layer to one side of a cantilever a chemical or biological sensor can be made. Molecules in the functional layer respond to specific chemical stimuli by producing an in plane surface stress – which causes the cantilevers to bend. This work was performed in collaboration with biochemists at UCL. Developed processes to fabricate SU8 cantilevers (image on left shows some fabricated cantilevers, seen from the underside). Performed the first comparison of polymer cantilevers with their silicon counterparts [4]. High Frequency Capacitance Measurements of Grain Boundaries in Y1-xCaxBa2Cu2O7-δ Measurement Frequency (GHz) 0 40 80 120 160 200 240 Developed a technique to use Josephson Junctions to measure the capacitance of Y1-xCaxBa2Cu2O7-δ grain boundaries at low Capacitance per unit area (Fm ) -2 1.8 Temperature: J 4.2 K temperatures and high frequencies. The figure on the left shows 1.6 15.0 K the capacitance of a grain boundary changing at lower frequencies as a result of a sharp increase in the permittivity of the high 1.4 dielectric constant SrTiO3 substrate on which the grain boundary 1.2 was fabricated. Above 200GHz the intrinsic grain boundary capacitance is measured. The temperature dependence of the 1 0 0.1 0.2 0.3 0.4 0.5 capacitance changes is consistent with the known high frequency Return Voltage (mV) properties of SrTiO3 [6, 9,10]. Normal State Resistance of YBa2Cu2O7-δ Grain Boundaries – Measurements and Theory Applied a Wheatstone bridge technique to measure the resistance of thin film YBa2Cu2O7-δ grain boundaries. A thin film artificial grain boundary was aligned with a Wheatstone bridge as shown on the left so that the boundary unbalances the bridge (an AFM image of part of a device is also shown below). This enabled measurements of grain boundary resistances that were much smaller than the interconnect resistances [5, 7, 8]. Developed the first model for tunnelling through YBa2Cu2O7-δ grain boundaries that incorporated a realistic band structure as well as band bending effects. Set up collaboration with the Cavendish theory of condensed matter group to compute results for a 3D band structure. This model was shown to be consistent with the available experimental data [7, 12]. View slide
  • Publications (in reverse chronological order) Papers: [1] M. Ferri, F. Mancarella, A. Roncaglia, J. H. T. Ransley, J. Yan and A. Seshia “Fabrication of DETF sensors in SOI technology with submicron air gaps using a maskless line narrowing technique”, Proceedings of the 7th IEEE Conference on Sensors , Lecce, Italy (2008). [2] J.H.T. Ransley, A. Aziz, C. Durkan and A.A. Seshia, “Silicon depletion layer actuators” Applied Physics Letters 92, 184103 (2008). Selected for publication in the Virtual Journal of Nanoscience and Nanotechnology, 17(21), (2008). [3] J.H.T. Ransley, C. Durkan and A.A. Seshia, “A Depletion Layer Actuator”, Proceedings of Transducers 2007, Lyons, France. [4] J.H.T. Ransley, M. Watari, D. Sukumaran, R.A. McKendry, A.A. Seshia, “SU8 Bio-Chemical Sensor Microarrays”, Microelectronic Engineering 83, 1621-1625 (2006). [5] S. H. Mennema, J. H. T. Ransley, G. Burnell, J. L. MacManus-Driscoll, E. J. Tarte, and M. G. Blamire, “Normal-State Properties of High-Angle Grain Boundaries in (Y, Ca)Ba2Cu3O7-δ”, Physical Review B 71, 094509 (2005). Selected for publication in the Virtual Journal of Applications of Superconductivity 8(7), (2005) [6] J. H. T. Ransley, P. F. McBrien, G. Burnell, E. J. Tarte, J. E. Evetts, R. R. Schulz, C. W. Schneider, A. Schmehl, B. Goetz, H. Bielefeldt, H. Hilgenkamp and J. Mannhart “Capacitance Measurements on Grain Boundaries in Y1-xCaxBa2Cu2O7-δ ”, Physical Review B 70, 104502 (2004). Selected for publication in the Virtual Journal of Applications of Superconductivity 7(6), (2004) [7] J. H. T. Ransley, S. H. Mennema, K. G. Sandeman, G. Burnell, E. J. Tarte, M. G. Blamire, J. E. Evetts, J. Kye and B. Oh, “Normal State Resistance of Grain Boundaries inYBa2Cu2O7-δ”, Applied Physics Letters 84(20), 4089-4091 (2004). Selected for publication in the Virtual Journal of Applications of Superconductivity 6(10), (2004) [8] J. H. T. Ransley, S. H. Mennema, G. Burnell, U. Balasumbramaniam, E. J. Tarte, M. G. Blamire, J. E. Evetts, J. Kye and B. Oh, “Y-Ba-Cu-O Grain Boundary Resistivity above and below the Critical Temperature”, IEEE transactions on Applied Superconductivity 13(2), 2866-2889 (2003). [9] E.J. Tarte, P. F. Mcbrien, J. H. T. Ransley, R. H. Hadfield, E. I. Inglessi, W. E. Booij, G. Burnell and J. E. Evetts, “Capacitance as a probe of high angle grain boundary transport in oxide superconductors”, IEEE transactions on Applied Superconductivty 11(1), 418-421 (2001). [10] J. H. T. Ransley, P. F. McBrien, G. Burnell, E. J. Tarte, J. E. Evetts, R. R. Schulz, C. W. Schneider, A. Schmehl, B. Goetz, H. Bielefeldt, H. Hilgenkamp and J. Mannhart “Capacitance Measurements on Grain Boundaries in Y1-xCaxBa2Cu3O7-δ”, Proceedings of the International Workshop on Critical Currents, Göttingen, Germany, 31-33 (2001). Patents: [11] J. H. T. Ransley, C. Durkan and A. Seshia, “Depleted Layer-Transducer”, Publication Number WO2008001082 (27 June 2006). Thesis: [12] J. H. T. Ransley, “The properties of Grain Boundaries in YBa2Cu3O7−δ”, PhD Thesis, University of Cambridge, 2004 (http://www.dspace.cam.ac.uk/handle/1810/34596). Referees available on request View slide