Danny Ramasawmy

Position:	Postdoctoral Research Fellow
Email:	danny.ramasawmy.15@ucl.ac.uk
Phone:	+44 (0) 20 3108 1199
Extension:	51199
Room:	Malet Place Engineering Building, 3.23
Address:	Department of Medical Physics and Biomedical Engineering University College London Malet Place Engineering Building Gower Street, London, WC1E 6BT

About

Short Bio

I studied an integrated Masters in Aerospace Engineering at the University of Southampton. I had scope to study a wide range of multidisciplinary modules and chose a bachelors thesis in modelling glucose transport across the placenta. This sparked my interest in medical physics and numerical modelling and motivated me to join the CDT in Medical Imaging in 2015 where I became part of the Biomedical Ultrasound Group. Since completing my PhD in early 2020 I have continued as a Postdoctoral Research Fellow.

Current Research

My research is focused on modelling the directional response of Fabry-Perot ultrasound sensors. These sensors are optical interferometers which can have superior characteristics to traditional piezoelectric devices.

Planar Fabry-Perot sensors consist of multiple elastic layers. The directional response of these sensors can be modelled analytically using multi-layer models of elastic wave propagation based on the partial-wave method. My implementation of this model has been packaged into a Matlab software toolbox (ElasticMatrix) and is available for download from GitHub and the mathworks FileExchange (see below). A comparison of the model with measurements made on a sensor had excellent agreement. In addition, the features of the measured and modelled FP acoustic sensitivity are related to elastic-wave phenomena caused by the complex interaction of the ultrasound waves with the layered structure of the sensor.

Fiber sensors have complex geometry and require more sophisticated modelling techniques. I am currently investigating these types of sensors with different numerical modelling techniques using the kWave Toolbox and Ansys.

ElasticMatrix Toolbox

The ElasticMatrix Toolbox uses the partial-wave method to model elastic wave propagation in multi-layered anisotropic media up to transverse-isotropic symmetry when the wave propagation is along a plane of symmetry.

Simulating the propagation of elastic waves in multi-layered media has many applications. A common approach is to use matrix methods where the elastic wave-field within each material layer is represented by a sum of partial waves along with boundary conditions imposed at each interface. While these methods are well-known, coding the required matrix formation, inversion, and analysis for general multi-layered systems is non-trivial and time consuming. ElasticMatrix is an open source toolbox which solves the problem of acoustic and elastic wave propagation in multi-layered media for isotropic and transverse-isotropic materials where the wave propagation occurs in a material plane of symmetry. The toolbox is implemented in MATLAB using an object oriented programming framework and is designed to be easy to use and extend. Methods are provided for calculating and plotting dispersion curves, displacement and stress fields, reflection and transmission coefficients, and slowness profiles.

Documentation | ElasticMatrix
Source Code | GitHub | Matlab FileExchange

Employment and Education

Post	Year
Postdoctoral Research Fellow Biomedical Imaging, Department of Medical Physics, University College London	2020 –
MPhil/PhD Biomedical Imaging, Department of Medical Physics, University College London	2016 – 2020
Masters in Research (Distinction) Biomedical Imaging, Department of Medical Physics, University College London	2015 – 2016
Winchester Science Centre Winchester Science Centre, Winchester	2014 – 2015
Integrated Masters of Engineering (1st Class Honours) Aeronautics and Astronautics Air Vehicle Systems and Design, Faculty of Engineering and the Environment, University of Southampton	2011 – 2015

Awards

Award	Year
Best student paper in the Sensors and NDE category at the International Ultrasonics Symposium, Washington DC	2017
Travel award to International Ultrasonics Symposium, Washington DC	2017
Best poster prize at CDT Summer School in Medical Imaging, London	2017
MRes + PhD Studentship for the EPSRC Center of Doctoral Training in Medical Imaging	2015