Catalonia's declaration of independence: what comes next?

The Catalan parliament's declaration of independence on 27 October, coupled with the Spanish government implementing direct rule over Catalonia, has left Spain facing its greatest political crisis since the country's transition to democracy. James Irving assesses what might happen next, writing that ultimately it will be the reaction of ordinary citizens that will determine where Catalonia is headed

Approximate actions for dynamical fermions

Recent developments and applications of approximate actions for full lattice QCD are described. We present first results based on the stochastic estimation of the fermion determinant on $12^3\times 24$ configurations at $\beta=5.2$.Comment: 3 pages, Latex, no figures, Contribution to Lattice 97, The XV International Symposium on Lattice Field Theory, Edinburgh 22-26 July 199

Near-optimum design of the InP homojunction solar cell

Using a fairly comprehensive model, researchers have done a parametric variation study of the InP n+p homojunction solar cell for AMO, 25 C operation. The results of this study are presented. These results indicate that an efficiency of about 25 percent should be realistically possible in a shallow homojunction InP solar cell with near-optimum design

Free radical reactions in solution

Phenylpropiolyl peroxide and its p-methyl -, p-methoxy-, p-chloro -, and p-bromo-substituted analogues have been synthesised in good yield and high purity by a method involving the reaction of the corresponding carboxylic acid with 98% hydrogen peroxide and dicyclohexylcarbodiimide.The parent compound has been decomposed in a variety of solvents and the mechanism of induced decomposition in these solvents investigated.The decomposition of the peroxides in chloroform at 65.0° in the presence of equimolar (0.05M) quantities of 3,4- dichloroetyrene to inhibit the induced decomposition enabled estimation of the first-order rate constants.Application of the Arrhenius' equation to the data from decompositions carried out in chloroform at different temperatures enabled estimation of the energy of activation for the decomposition of the parent compound and the p- methyl - and p- methoxy- analogues. The p-methoxy compound had a greatly enhanced rate of decomposition and lower activation energy - suggesting a different mechanism and the possibility of a non-homolytic decomposition.The synthesis of systems designed to differentiate between bridged and classical free radical intermediates by identification of the reaction products has been investigated.The production of radicals of this nature from aldehydes and azo compounds was unsuccessful due to the difficulty experienced in synthesis of the starting materials.The synthesis of 4-t-butyl-2-bromocyclohexylformyl peroxide has been achieved from the corresponding acid with 98% hydrogen peroxide and dicyclohexylcarbodiimide.4-t-butyl-l-cyanocyclohexene was found to undergo stereo-specific addition of hydrogen bromide to give exclusively the trans addition product, namely, trans-4-t-butyl-cis-2-bromo -l-cyanocyclohexane, under both free radical and ionic conditions. The significance of this in relation to bridged radicals is discussed.The decomposition of the bromo peroxide did not give the expected products when investigated under similar conditions to those employed for the parent compound, 4-t-butylcyclohexylformyl peroxide. This limited the amount of information that could be obtained

A study of the gelation of air-setting refractory mortars

Three basic mortar formulae were used in this investigation, each mix having some different materials present and each having its own gelling characteristics. The study was directed along the theory that the dry materials used play an important part in the hardening. Certain admixtures were tested and several were found to improve the workability after storage. The presence of additional sodium ions in the mortar was found to be helpful in overcoming the gelation but these tended to lower the refractoriness of the mortar. A study was made of the base exchange capacities of the dry materials and the material with the highest base exchange capacity was found to contribute more to the gelation than did one without so many exchangeable cations. The flame photometer was employed to analyze the concentration of the alkaline ions in the effluents obtained during the electrodialysis of a clay and the results indicated that the peaks in the time-current curve of the dialysis may be indicative of the relative amounts of the two valence-type ions removed. The effect of the mineral constituents of the clays used in the mortars was discussed. One of the clays was found to contain considerably more free silica than did the other clay. This did not seem to have too great an effect on the hardening during the storage period. Opal was found to be present in one of the clays and differential thermal curves were given in an attempt to use this method to determine whether or not this mineral was present. It was concluded that the gelation was not due to any one single factor but that the most predominant cause was the presence of polyvalent exchangeable cations adsorbed to the clay or other dry materials used in the mortars. The presence of free silica was found to cause some hardening, but this was deemed only a minor factor. The use of bentonite as a suspending medium in the mortar was found to be detrimental to the workability of the mortar as its high exchange capacity and high percentage of exchangeable magnesium was found to increase the gelation considerably --Abstract, pages ix-x