Chandra Sekar Ramanujan

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Chandra Sekar Ramanujan

Visiting Senior Scientist

•Tecnology Transfer and Marketing of Intellectual Property
•Media relations and th public understanding of science
•Development of sensors, probes, devices and instrumentation for academic and industrial applications
•Mechanical testing using a range of tools including strain gauges, shear and tension testers, optical microscopy of metallurgical samples and Atomic Force Microscopy.
•Materials testing using Scanning Electron Microscopy, Energy Dipsersive spectroccopy, X-ray Diffraction, Focussed Ion Beam Milling.
•Electrical testing of electronic components undergoing accelerated life testing.
•Study of fluids – experimentation and phenomenological modelling.

DPhil in Materials Science, University of Oxford.
Supervisor: Prof. John Pethica, FRS.
Thesis topic: “AFM and Nanomechanics in Ambient and Liquid Environments”

MSc in Materials Science and Engineering, University of Texas at Austin.
Supervisor: Prof. Arumugam Manthiram
Thesis topic: “The Synthesis and Characterization of YBa2Cu3O6+x Superconductor”

BSc in Mechanical Engineering, University of Texas at Austin.
Specialized Technical Block: Materials Science

•Atomic force microscopy of neural receptors reconstituted into lipid mixtures
•Atomic Force Microscopy in liquids
Helped construct a modified Atomic Force Microscope (AFM) that uses a Fabry-Perot Interferometer to detect changes in displacements down to 0.01 Angstroms. This small amplitude AFM has been used to study liquids in a confined space, successfully measuring oscillatory forces and dissipative effects of water close to both hydrophilic and hydrophobic surfaces. Carried out the only small amplitude AFM work in water using Carbon Nanotubes.

•Atomic Force Microscopy of Biomolecules
Imaging of Purple Membrane (PM) in liquid using the Asylum Research MFP-3D system and the Veeco Dimension 3100 system. Investigated the mechanical and electrical properties of PM using the AFM. Conducted pulling experiments on PM, measuring forces as the protein is extracted. Presently working on manipulating tailor-made vesicles to self-assemble on a patterned semiconductor surface.

•In-situ TEM Nanoindentation
Constructed an in-situ TEM nanoindenter that was built to fit the sample holder for the Jeol 2010 microscope. The nanoindenter incorporated a 3-axis piezo-driven inertial micropositioner and a force sensor. The force sensor uses a flexible hinge mechanism to achieve flexibility only in the axis of indentation, maintaining a high stiffness in the others. The force sensor was manufactured using lithography and wet etch technology.

•Direct measurement of scanning probe microscopy cantilever spring constant
Constructed an instrument to directly measure the spring constant of AFM cantilevers. The instrument was constructed on an optical bench using a calibrated test cantilever as a reference. It utilised a Fabry Perot interferometer to measure the deflection of the AFM cantilever while the corresponding deflection of the test cantilever was monitored separate interferometer.

•Development of novel interconnections used in electronic packaging
Developed a novel method of connecting silicon integrated circuit chips and FR-4 circuit boards. The method involved using a combination of gold wire-bonding and solder-enabled ‘flip-chip’ technology.
•Studied impact of microstructure on mechanical properties of fine gold wire
Used Nanoindentation and AFM to study the mechanical properties of 25μm diameter gold wire and related the mechanical properties to Scanning Electron Microscope (SEM) images of the cross-sectioned wire.
•Designed and conducted experiments on accelerated life testing on electronic packages.
Monitored efficiency of gold-wire bonded substrates as they underwent thermal cycling to simulate 10 years of practical use in the space of 1 month. The final samples were subjected to shear test and microstructural analysis as well as electrical testing.
•Synthesis and characterization of superconducting ceramics
Synthesis of YBa2Cu3O6+x by a sol-gel process and monitoring effects of processing temperature on oxygen content using X-ray Diffraction and SQUID.
•instituted Helium-mass-spectrometry leak detection testing for glass-packaging hermiticity into industrial quality control process