Laser-assisted bumping for flip chip assembly

Published versio

Thermosonic flip chip interconnection using electroplated copper column arrays

Published versio

Sacrificial layer process with laser-driven release for batch assembly operations

Published versio

Remote photothermal actuation for calibration of in-phase and quadrature readout in a mechanically amplified Fabry-Pérot accelerometer

A mechanically amplified Fabry-Pérot optical accelerometer is reported in which photothermal actuation is used to calibrate the in-phase and quadrature (I&Q) readout. The Fabry-Pérot interferometer (FPI) is formed between a gold-coated silicon mirror, situated in the middle of a V-beam amplifier, and the end surface of a cleaved optical fiber. On the opposite side of the silicon mirror, a further cleaved optical fiber transmits near-infrared laser light (λ = 785 nm), which is absorbed by the uncoated silicon causing heating. The thermal expansion of the V-beam is translated into an amplified change in cavity length of the FPI, large enough for the 2π-phase variation necessary for I&Q calibration. A simple 1D thermal analysis of the structure has been developed to predict the relationship between laser power and change in cavity length. A device having a V-beam of length 1.8 mm, width 20 μm, and angle 2 ° was found to undergo a cavity length change of 785 nm at 30 mW input power. The device response was approximately linear for input accelerations from 0.01 to 15 g. The noise was measured to be ~ 60 μg/√Hz from 100 Hz to 3.0 kHz, whereas the limit of detection was 47.7 mg from dc to 3.0 kHz

On the angular dependence of focused laser ablation by nanosecond pulses in solgel and polymer materials

Published versio

Measurement of stator heat transfer in air-cooled axial flux permanent magnet machines

Published versio

Prediction and measurement of heat transfer in air-cooled disc-type electrical machines

Accurate thermal analysis of axial flux permanent magnet (AFPM) machines is crucial in predicting maximum power output. Stator convective heat transfer is one of the most important and least investigated heat transfer mechanisms and is the focus of this paper. Experimental measurements were undertaken using a thin-film electrical heating method, providing radially resolved steady state heat transfer data from an experimental rotor-stator system designed as a geometric mockup of a through-flow ventilated AFPM machine. The measurements are compared with computational fluid dynamics (CFD) simulations using both 2D axisymmetric and 3D models. These were found to give a conservative estimate of heat transfer, with inaccuracies near the edge and in the transitional flow regime. Predicted stator heat transfer was found to be relatively insensitive to the choice of turbulence model and the SST model was used for most of the simulations.Accepted versio

Architectures for vibration-driven micropower generators

Published versio

Scaling Laws for Energy Harvesters in a Marine Environment

Published versio

Self-powered wireless sensor for duct monitoring

Accepted versio