WITHDRAWN: Non-isothermal multiphase flow and reactive transport modelling of compacted bentonite simultaneously heated and hydrated.
Ahead of Print article withdrawn by publisher.
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Biomedical subjects
Jordi Delgado
Publications and source records attributed to Jordi Delgado.
Clustering algorithm for determining community structure in large networks.
We propose an algorithm to find the community structure in complex networks based on the combination of spectral analysis and modularity optimization. The clustering produced by our algorithm is as accurate as the best algorithms on the literature of modularity optimization; however, the main asset of the algorithm is its efficiency. The best match for our algorithm is Newman's fast algorithm, which is the reference algorithm for clustering in large networks due to its efficiency. When both algorithms are compared, our algorithm outperforms the fast algorithm both in efficiency and accuracy of the clustering, in terms of modularity. Thus, the results suggest that the proposed algorithm is a good choice to analyze the community structure of medium and large networks in the range of tens and hundreds of thousand vertices.
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An Experimental Study on the Ion-Exchange Behavior of the Smectite of Cabo de Gata (Almería, Spain): FEBEX Bentonite.
Binary cation-exchange processes (Na-K, Na-Mg, and Na-Ca) have been investigated at 25 degrees C in samples of bentonite from Cabo de Gata (Almería, SE Spain). Exchange isotherms and Vanselow selectivity coefficients indicate that the preference of this bentonite for K(+), Ca(2+), and Mg(2+) ions is greater than that for the Na(+) ion. The change in (i)(j)K(V) as a function of the equivalent fraction of cation M, E(M), is interpreted on the basis of the presence of different types of adsorption/exchange sites (tetrahedral, octahedral, and edge sites). For the Na/K exchange, (K)(Na)K(V) exhibits a steep decrease for E(K)<0.25-0.3. This is interpreted as due to preferential exchange at the tetrahedral sites. However, the opposite behavior is observed in the case of Ca and Mg, with a noticeable increase of (i)(Na)K(V) for E(Ca)(E(M(g)))>0.6-0.8. The compared selectivities of Ca and Mg for this smectite are nearly equal. As far as the exchanger is concerned, the Na-Ca and Na-Mg exchange is nearly ideal, in the raoultian sense. Thermodynamic exchange constants and the corresponding Gibbs free energies of reaction have been computed from (i)(j)K(V) coefficients. This allow us to quantify the exchanger's affinity sequence, which appears to be Na(+)<K(+)<Mg(2+)<Ca(2+). Copyright 2001 Academic Press.
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