No abstract

Design requirements for an 8000 frame/s dual-wavelength ratiometric chemical species tomography system, intended for hydrocarbon vapor imaging in one cylinder of a standard automobile engine, are examined. The design process is guided by spectroscopic measurements on iso-octane and by comprehensive results from laboratory phantoms and research engines, including results on temporal resolution performance. Novel image reconstruction techniques, necessary for this application, are presented. Recent progress toward implementation, including details of the optical access arrangement employed and signal-to-noise issues, is described. We present first cross-cylinder IR absorption measurements from a reduced channel-count (nontomographic) system and discuss the prospects for imaging.

No abstract

In this note we describe a proof-of-principle acoustic emission based damage detection experiment. A large carbon fibre composite structure was made to resemble an aerospace component. This structure was dynamically loaded after damage. Optical fibre sensors detected acoustic emission events during the load cycles. These trials demonstrate that acoustic emission is suitable for damage detection in carbon fibre composite structures and that optical fibre sensors are sensitive enough for the task.

Onychomycosis is common, affecting approximately 5% of the population, and is the most resistant form of superficial fungal infection. Dermatologists often view the nail apparatus in static terms and unfortunately give little consideration to the functional aspects of the digit. In the case of toenails, it is important to consider the toes and foot as a closely integrated functional unit. It is essential that in any case of onychomycosis or onychodystrophy that, as clinicians, we have an understanding of foot dynamics, of structure/function relationships and of the implications of orthopaedic/podiatric factors when evaluating cases of nail dystrophy. When confronted with cases of possible onychomycosis, we must adopt a systematic and sometimes multidisciplinary approach in the evaluation and management of these patients to improve patient outcomes.

Three types of commercially available headnet electrode arrays, designed for use in EEG, and conventional EEG Ag/AgCl cup electrodes were tested on human subjects, and a realistic, saline-filled head-shaped tank was prepared with vegetable skin to simulate human skin in order to determine the optimum electrode system for electrical impedance tomography (EIT) of the human head. Impedance changes during EIT acquisition were produced in healthy volunteers during a finger-thumb apposition task and in tanks by the insertion of a Perspex rod. Signal-to-baseline noise, measured from raw EIT data, was 2.3 +/- 0.3 and 2.3 +/- 0.2 for the human and tank data, respectively. In both the human and tank experiments, a commercial hydrogel elasticated electrode headnet produced the least amount of baseline noise, and was the only headnet in the human data with noise levels acceptable for EIT imaging. Image quality measured in the tank was similar for most of the headnets tested, except that the EEG electrodes produced a higher positional error and electrodes in a geodesic elasticated net produced images with worse subjective image quality. Overall, the hydrogel elasticated headnet was judged to be the most suitable for human neuroimaging with EIT.

No abstract

No abstract