A survey of the Australasian clinical medical physics and biomedical engineering workforce

A survey of the medical physics and biomedical engineering workforce was carried out in 2006. 495 positions(equivalent to 478 equivalent full time (EFT) positions) were captured by the survey. Of these 268 EFT were in radiation oncology physics, 36 EFT were in radiology physics, 44 were in nuclear medicine physics, 101 EFT were in biomedical engineering and 29 EFT were attributed to other activities. The survey reviewed the experience profile, the salary levels and the number of vacant positions in the workforce for the different disciplines in each Australian state and in New Zealand. Analysis of the data identifies staffing shortfalls in the various disciplines and demonstrates the difficulties that will occur in trying to train sufficient physicists to raise staffing to an acceptable level

A 2009 survey of the Australasian clinical medical physics and biomedical engineering workforce

A survey of the Australasian clinical medical physics and biomedical engineering workforce was carried out in 2009 following on from a similar survey in 2006. 621 positions (equivalent to 575 equivalent full time (EFT) positions) were captured by the survey. Of these 330 EFT were in radiation oncology physics, 45 EFT were in radiology physics, 42 EFT were in nuclear medicine physics, 159 EFT were in biomedical engineering and 29 EFT were attributed to other activities. The survey reviewed the experience profile, the salary levels and the number of vacant positions in the workforce for the different disciplines in each Australian state and in New Zealand. Analysis of the data shows the changes to the workforce over the preceding 3 years and identifies shortfalls in the workforce

Studies of the coefficient of variation of the magnitude of EEG signals

An analysis of the variation in magnitude of EEG signals in various frequency bands of anesthetized patients and normal sleeping volunteers was carried out. The coefficient of variation (CoV), i.e. the standard deviation/mean, within 10 second epochs was found to be quite constant throughout the whole of the EEG recordings and was typically about 0.46. This was found to be the case for both the patients and the volunteers. Histograms of the magnitudes indicated that the magnitudes are distributed as f(x)=βxe(-αx2) functions. However a CoV of 0.46 is consistent with f(x)=βxe(-αx3) functions. The non-stationary nature of the EEG is such that it is likely that while over short periods the EEG magnitudes are distributed as f(x)=βxe(-αx3) functions, variations of α over time mean that in the long term the EEG magnitudes are distributed as f(x)=βxe(-αx2) functions

An experimental investigation of the damping contribution of an elastomeric ablator on aluminum beams

Damping results are presented for an elastometric ablation material bonded to an aluminum alloy substrate. Tests were conducted on aluminum beams 0.159, 0.318, and 0.476 cm thick, and with and without an ablator. Ablation-material thickness varied from 0.159 to 0.953 cm. Comparative damping data were obtained by using variations of the free-free beam technique with strain gages and piezoelectric transducers. Of the two test arrangements employed, the technique using strain gages produced results that indicated less restraint of the beams. Ablation material, in thicknesses less than 1 cm, substantially increased the damping parameter of the aluminum beams

Ablative performance of various low-density elastomeric composites

Performance of low density silicone-phenolic and commercial ablative composite

Fringe counter for interferometers Patent

Digital sensor for counting fringes produced by interferometers with improved sensitivity and one photomultiplier tube to eliminate alignment proble

Mathematical modelling of the overflowing cylinder experiment

The overflowing cylinder (OFC) is an experimental apparatus designed to generate a controlled straining flow at a free surface, whose dynamic properties may then be investigated. Surfactant solution is pumped up slowly through a vertical cylinder. On reaching the top, the liquid forms a flat free surface which expands radially before overflowing down the side of the cylinder. The velocity, surface tension and surfactant concentration on the expanding free surface are measured using a variety of non-invasive techniques. A mathematical model for the OFC has been previously derived by Breward, Darton, Howell and Ockendon and shown to give satisfactory agreement with experimental results. However, a puzzling indeterminacy in the model renders it unable to predict one scalar parameter (e.g. the surfactant concentration at the centre of the cylinder), which must be therefore be taken from the experiments. In this paper we analyse the OFC model asymptotically and numerically. We show that solutions typically develop one of two possible singularities. In the first, the surface concentration of surfactant reaches zero a finite distance from the cylinder axis, while the surface velocity tends to infinity there. In the second, the surfactant concentration is exponentially large and a stagnation point forms just inside the rim of the cylinder. We propose a criterion for selecting the free parameter, based on the elimination of both singularities, and show that it leads to good agreement with experimental results

Straining flow of a micellar surfactant solution

We present a mathematical model describing the distribution of monomer and micellar surfactant in a steady straining flow beneath a fixed free surface. The model includes adsorption of monomer surfactant at the surface and a single-step reaction whereby $n$ monomer molecules combine to form each micelle. The equations are analysed asymptotically and numerically and the results are compared with experiments. Previous studies of such systems have often assumed equilibrium between the monomer and micellar phases, i.e. that the reaction rate is effectively infinite. Our analysis shows that such an approach inevitably fails under certain physical conditions and also cannot accurately match some experimental results. Our theory provides an improved fit with experiments and allows the reaction rates to be estimated