Correlation between acid strength (Ho) and ammonia desorption temperature for aluminas and silica-aluminas

Correlation between the temperature at which a base is desorbed and the acid strength (H_o) of the sites set free by it, was looked for. Ammonia was employed as base. A linear correlation of the type H_o=+/T (K) is valid with and constants, dependent on the adsorbate and the adsorbent.

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(H_o) , . H_o=+/T (K), .

     

Superparamagnetic gamma-Fe(2)O(3) nanoparticles with tailored functionality for protein separation

Polymer coated superparamagnetic gamma-Fe(2)O(3) nanoparticles were derivatized with a synthetic double-stranded RNA [poly(IC)], a known allosteric activator of the latent (2-5)A synthetase, to separate a single 35 kDa protein from a crude extract which cross reacted with antibodies raised against the sponge enzyme.     

Memetic Algorithms: The Polynomial Local Search Complexity Theory Perspective

In previous work (Krasnogor, . In: Studies on the Theory and Design Space of Memetic Algorithms. Ph.D. thesis, University of the West of England, Bristol, UK, 2002; Krasnogor and Smith, IEEE Trans Evol Algorithms 9(6):474–488, 2005) we develop a syntax-only classification of evolutionary algorithms, in particular so-called memetic algorithms (MAs). When “syntactic sugar” is added to our model, we are able to investigate the polynomial local search (PLS) complexity of memetic algorithms. In this paper we show the PLS-completeness of whole classes of problems that occur when memetic algorithms are applied to the travelling salesman problem using a range of mutation, crossover and local search operators. Our PLS-completeness results shed light on the worst case behaviour that can be expected of a memetic algorithm under these circumstances. Moreover, we point out in this paper that memetic algorithms for graph partitioning and maximum network flow (both with important practical applications) also give rise to PLS-complete problems.

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Electronic Supplementary Material The online version of this article (doi:) contains supplementary material, which is available to authorized users.      

A genotype-phenotype-fitness assessment protocol for evolutionary self-assembly Wang tiles design

In a previous work we have reported on the evolutionary design optimisation of self-assembling Wang tiles capable of arranging themselves together into a target structure. Apart from the significant findings on how self-assembly is achieved, nothing has been yet said about the efficiency by which individuals were evolved. Specially in light that the mapping from genotype to phenotype and from this to fitness is clearly a complex, stochastic and non-linear relationship. One of the most common procedures would suggest running many experiments for different configurations followed by a fitness comparison, which is not only time-consuming but also inaccurate for such intricate mappings. In this paper we aim to report on a complementary dual assessment protocol to analyse whether our genetic algorithm, using morphological image analyses as fitness function, is an effective methodology. Thus, we present here fitness distance correlation to measure how effectively the fitness of an individual correlates to its genotypic distance to a known optimum, and introduce clustering as a mechanism to verify how the objective function can effectively differentiate between dissimilar phenotypes and classify similar ones for the purpose of selection.     

Influence of the chlorine content of Al2O3 on its catalytic activity and coke formation

The catalytic activities of aluminas with different chlorine contents for cumene cracking, o-xylene isomerization, n-hexane isomerization and cracking and methylcyclopentane cracking were studied. The catalytic activity and the acidity increase continuously when the chlorine content increases. Coke formation is only noticiable with methylcyclopentane, increasing with the chlorine content of the alumina.

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