The chemistry of Antarctic ozone 1960-1987

The factors that influence Antarctic ozone are examined with a view to understanding the observed historical trend. Researchers show that reduced ambient temperatures can dramatically enhance the efficiency of chemical removal processes. Attention is focused on positive feedback between levels of ozone, temperature, and rates of heterogeneous chemical reactions. ClO and its dimer, and high levels of these gases are maintained until the clouds evaporate, on 15 September for the simulation shown here

The Three Component Electronic Structure of the Cuprates Derived from SI-STM

We present a phenomenological model that describes the low energy electronic structure of the cuprate high temperature superconductor Bi2Sr2CaCu2O8+x as observed by Spectroscopic Imagining Scanning Tunneling Microscopy (SI-STM). Our model is based on observations from Quasiparticle Interference (QPI) measurements and Local Density of States (LDOS) measurements that span a range of hole densities from critical doping, p~0.19, to extremely underdoped, p~0.06. The model presented below unifies the spectral density of states observed in QPI studies with that of the LDOS. In unifying these two separate measurements, we find that the previously reported phenomena, the Bogoliubov QPI termination, the checkerboard conductance modulations, and the pseudogap are associated with unique energy scales that have features present in both the q-space and LDOS(E) data sets

Making automation pay - cost & throughput trade-offs in the manufacture of large composite components

The automation of complex manufacturing operations can provide significant savings over manual processes, and there remains much scope for increasing automation in the production of large scale structural composites. However the relationships between driving variables are complex, and the achievable throughput rate and corresponding cost for a given design are often not apparent. The deposition rate, number of machines required and unit production rates needed are interrelated and consequently the optimum unit cost is difficult to predict. A detailed study of the costs involved for a series of composite wing cover panels with different manufacturing requirements was undertaken. Panels were sized to account for manufacturing requirements and structural load requirements allowing both manual and automated lay-up procedures to influence design. It was discovered that the introduction of automated tape lay-up can significantly reduce material unit cost, and improve material utilisation, however higher production rates are needed to see this benefit