Adaptation of drafting plotter for buried contact groove formation

Lasers (e.g. Nd-YAG) have been used extensively for groove formation both in laboratories and commercial production but the initial capital cost is high. The production throughput is also low and thus adds to the cost of the cell. To reduce cost and increase production throughput a drafting plotter has been adapted to serve as a mechanical scriber for groove formation. The adapted plotter can scribe cells in matrix form to reduce the human labour and increase the production throughput. The characterization of the scribing tips in conjunction with the plotter showed that the best yield for the scriber is obtained when the scribing tip is mounted at 78° to the stock. Of the seven characterized scribing tips, the 90° conical scriber has been found to give the same groove geometry as the laser. The application of the adapted plotter to cell fabrication did not show any significant deterioration in the electrical output parameters for the mechanically scribed cells when compared with laser scribed cells. This article reports the adaptation of the x-y table drafting plotter to form buried contact grooves.     

Confirmatory factor analysis of the Wechsler Memory Scale-Revised in a sample of clients with alcohol dependency

Previous analyses of the Wechsler Memory Scale-Revised (WMS-R; Wechsler, 1987) have reported one-, two-, and three-factor solutions and raised questions about the validity of the visual memory subtests. These various findings may stem in part from different methods of analysis, and from the study of different participant samples. To address these issues, we analysed data from the WMS-R and a spatial maze test administered to 154 participants with a history of alcohol dependence. Results from confirmatory factor analysis supported the interpretation of three factors underlying the WMS-R subtests and the spatial maze score in this sample, namely, attention-concentration, immediate memory, and delayed recall. This result held despite the inclusion of the maze score which is a well-validated measure of visuo-spatial memory.     

Development of manufacturing control strategies using unsupervised machine learning

This research considers the control of manufacturing systems that support job routing and process sequence flexibility. A machine learning system is presented that uses a simulation model of the target manufacturing system to discover opportunistic control rules. Learning is unsupervised and is driven by a genetic algorithm. The learning method requires very little a priori control knowledge. For this presentation, the decision-making agents are the part types being processed. Part types evolve cooperative strategies for selecting the best route through the manufacturing system based on simulated real-time information that describes the state of the system. Results are presented that demonstrate the effectiveness of the approach.     

Effect of silver addition on superconductivity in the Bi1.6Pb0.4Sr1.6Ca2Cu3O10−y system

Silver/superconductor composites containing 0 to 80 vol% silver have been prepared and their properties determined. Optimum heat treatment at sintering temperatures ( 800° C) under low oxygen pressures produces material with high critical current density and improves physical properties. Magnetic susceptibility measurements have been found to be consistent with resistivity results. In order to retain a single high-T _c phase with increasing silver content, decreased oxygen partial pressures are required. Using the normal-state resistivity of these composites, a percolation threshold at a silver volume fraction of 43% was observed, while zero resistivity measurements show that a continuous superconducting network can be obtained with up to 80 vol% silver. The critical current density of 21 vol% silver-doped samples was found to be 1520 A cm^–2 at 77.3 K, compared to 260 A cm^–2 for an undoped sample.     

Synthesis of telechelic monodispersed diols

Summary The synthesis of telechelic monodispersed diols produced from the radical telomerization of an excess of undecylenol with commercialy available , -dithiols HSC₂H₄XC₂H₄SH (X=0, S or CH₂) initiated by peroxides is presented. In each case, the diols were obtained selectively and quantitatively and they were characterized by both ¹H and ¹³C NMR. Their physical characteristics (Tg, T_m and decomposition temperatures) were determined. Such compounds are thermally more stable than polydispersed telechelic commercially available diols.     

The availability of nitrogen following topsoil application of liquid digested sludge

Samples (375 g) of the Evesham series (clay loam) soil were incubated under aerobic conditions at 20 °C following incorporation of liquid mesophilic digested sewage sludge (1150 mg N L^–1). Simultaneously, pot trials under field conditions were also established. Total soluble N total oxides of nitrogen, ammonium N and headspace carbon dioxide samples were determined periodically over the first 480 day degrees C. Soluble organic N fractions were also calculated and it was found that the soil water concentration of available N (as nitrate N) could be predicted from summation of SON and NH₄-N on sludge application. The accumulation of nitrate N was compared with field derived data and both correlated well to a 2 pool exponential model. High rates of nitrification were observed and 70% of the organic N applied was mineralised over 480 day degrees C. The use of the relative quantity of soluble to insoluble organic N could be a possible indicator of subsequent nitrogen availability in field application.     

Nitrogen-containing aluminium titanate

In the Ti-Al-O-N system a phase isostructural to aluminium titanate but with expanded unit cell dimensions was observed. It was stable between 1400 and 1700 °C and has unit cell dimensions of a=0.3719 nm, b=0.9703 nm and c=0.9869 nm with a composition of Ti _1.00 ⁴⁺ Al _0.54 ³⁺ Ti _1.46 ³⁺ N _0.28 ^3– O _4.58 ^2– _0.14 Several samples were prepared by reaction sintering mixtures of TiN, Al₂O₃ and AlN powders at 1400 to 1470 °C for 4 h in a nitrogen atmosphere to maximize this phase. One specific advantage of the nitrogen-containing aluminium titanate over aluminium titanate is that the former is unchanged at 1150 °C in a nitrogen atmosphere whereas the latter decomposes. In the Al₂O₃-TiO₂ oxide system Al₂TiO₅ solid solution extends to approximately Al_0.75Ti_2.25O₅ at 1470 °C under the mildly reducing conditions of a graphite furnace. The unit cell volume increases linearly with the increasing replacement of Al³⁺ by Ti³⁺.     

Mutual information for Lucas-Kanade Tracking (MILK): an inverse compositional formulation

Mutual Information (MI) is popular for registration via function optimisation. This work proposes an inverse compositional formulation of MI for Levenberg-Marquardt optimisation. This yields a constant Hessian, which may be pre-computed. Speed improvements of 15% were obtained, with convergence accuracies similar to those of the standard formulation.     

The Impact of Interaction and Social Learning on Aggregate Expectations

We examine the effect of information sharing within small world networks. Agents receive a signal correlated with the state of the world (SoW) which is adjusted following discussions with neighbours. If one agent in the network, referred to as an expert, does not engage in social learning (that is they always follow their own signal) then all agents learn the SoW. It is found that volatility in the mean level of expectations varies with changes in the number of experts and the network structure. A trade-off emerges between the level of volatility and the speed at which agents learn of changes to the SoW. A second finding is that certain network structures lead to information cascades.