Quality control criteria for acceptance testing of cross-wire welds

Visual inspection criteria assure the metallurgical integrity of spot welds joining nickel leads and nickel ribbon in a 90 degree cross-wire configuration

Optically coupled digital altitude encoder for general aviation altimeters

An optically coupled pressure altitude encoder which can be incorporated into commercially available inexpensive general aviation altimeters was successfully developed. The encoding of pressure altitude is accomplished in 100-ft (30.48-m) increments from -1000 to 20,000ft (-304.8 to 6096 m). The prototype encoders were retrofitted into two different internal altimeter configurations. A prototype encoder was checked for accuracy of transition points and environmental effects. Each altimeter configuration, with the encoder incorporated, was laboratory tested for performance and was subsequently flight-tested over the specified altitude range. With few exceptions, the assembled altimeter-encoder met aeronautical standards for altimeters and encoders. Design changes are suggested to improve performance to meet required standards consistently

Adams operations on the Green ring of a cyclic group of prime-power order

We consider the Green ring $R_{KC}$ for a cyclic $p$-group $C$ over a field $K$ of prime characteristic $p$ and determine the Adams operations $\psi^n$ in the case where $n$ is not divisible by $p$. This gives information on the decomposition into indecomposables of exterior powers and symmetric powers of $KC$-modules.Comment: 23 page

The Decomposition of Lie Powers

Let G be a group, F a field of prime characteristic p and V a finite-dimensional FG-module. Let L(V) denote the free Lie algebra on V regarded as an FG-submodule of the free associative algebra (or tensor algebra) T(V). For each positive integer r, let L^r(V) and T^r(V) be the rth homogeneous components of L(V) and T(V), respectively. Here L^r(V) is called the rth Lie power of V. Our main result is that there are submodules B_1, B_2, ... of L(V) such that, for all r, B_r is a direct summand of T^r(V) and, whenever m \geq 0 and k is not divisible by p, $$L^{p^mk}(V) = L^{p^m}(B_k) \oplus L^{p^{m-1}}(B_{pk}) \oplus ... \oplus L^p(B_{p^{m-1}k}) \oplus L^1(B_{p^mk}).$$ Thus every Lie power is a direct sum of Lie powers of p-power degree. The approach builds on an analysis of T^r(V) as a bimodule for G and the Solomon descent algebra.Comment: 32 page

The matrix reloaded? why we should improve the MPS ‘gang violence matrix’, not dismantle it

An article for Police Professional magazine (published 21 June 2018) arguing for the retention (but reform) of the MPS 'Gang violence database'

An Infrared Study of Centaurus A

We present J, H and K-band images and 0.9-2.5 micron spectra of the nuclear regions of Centaurus A obtained with IRIS on the AAT. While K band has a point source coincident with the nucleus, at H and J we identify diffuse structure extending to the NE as a possible ionisation cone. By considering the NIR colours we show that the point-like K-band emission originates not from the nucleus itself, but from dust which has been shock heated by nuclear outflows. A J-K image reveals a band of high extinction across the nucleus lying perpendicular to the radio jet axis, as suggested by previous authors (Israel et al. 1990, Turner et al. 1992). We model the detailed structure of this extinction image with a circumnuclear torus of diameter 240+/-20 pc, thickness 75+/-4 pc, tilt 80+/-2 degrees to the line of sight and with the torus and radio jet axes aligned.Comment: Submitted to MNRAS on 6th Aug 1998. 12 latex pages including 4 postscript figures. 6 jpg colour figures are attached and can also be found at http://www.physics.usyd.edu.au/~jbryant/cenapub.htm