A survivable design of last mile communication networks using multi-objective genetic algorithms

In this paper, we are interested in the survivable network design problem (SNDP) for last mile communication networks called (L-SNDP). Given a connected, weighted, undirected graph \(\mathrm{{G}} = (\mathrm{V, E})\); a set of infrastructure nodes and a set of customers C including two customer types where customers in the subset C1 require a single connection (type-1) and customers in the subset C2 need to be redundantly connected (type-2). The aim is to seek a sub-graph of G with the smallest weight in which all customers are connected to infrastructure nodes and the connections are protected against failures. This is a NP-hard problem and it has been solved only with the objective of minimizing the network cost. In this paper, we introduce a new multi-objective approach to solve L-SNDP called ML-SNDP. These objectives are to minimize the network cost (total cost) and to minimize the maximal amount of sharing links between connections. Results of computational experiments reported show the efficiency of our proposal.     

Physical characteristics of Saccharomyces cerevisiae

We examined the physical properties of the surrounding yeast cell walls by using atomic force microscopy (AFM). The yeast cells were prepared on a cleaned glass substrate for confocal microscopy (CM) observation and were mechanically trapped into a porous membrane for AFM measurement. The confocal image of the yeast cells was measured in air, meanwhile the AFM topography images of the cells were measured in both deionized (DI) water (pH = 6.9) and phosphate‐buffered saline (PBS) solution (pH = 7.4). No significant differences between the AFM topography images of the yeast cells measured in DI water and in PBS solution could be inferred. In order to get the quantitative information on the sample elasticity, the force curves between an AFM tip and the yeast cell have been measured. These curves were measured in both DI water and in PBS solution on the same yeast cell using the same AFM cantilever to get the reliable result. The contact region of the force curve in approach mode was then converted into force versus indentation curve, which would be fitted with Hertz–Sneddon model for the calculation of the elasticity. Analysis of the curves indicates that there is a difference of the Young's modulus values of the yeast cell in various environments. These data show that the salt buffer solution increases the rigidity of the biological system. Copyright © 2008 John Wiley & Sons, Ltd.     

QSAR modeling on benzo[c]phenanthridine analogues as topoisomerase I inhibitors and anti-cancer agents

Benzo[c]phenanthridine (BCP) derivatives were identified as topoisomerase I (TOP-I) targeting agents with pronounced antitumor activity. In this study, hologram-QSAR, 2D-QSAR and 3D-QSAR models were developed for BCPs on topoisomerase I inbibitory activity and cytotoxicity against seven tumor cell lines including RPMI8402, CPT-K5, P388, CPT45, KB3-1, KBV-1and KBH5.0. The hologram, 2D, and 3D-QSAR models were obtained with the square of correlation coefficient R2 = 0.58-0.77, the square of the crossvalidation coefficient q2 = 0.41-0.60 as well as the external set's square of predictive correlation coefficient r2 = 0.5-0.80. Moreover, the assessment method based on reliability test with confidence level of 95% was used to validate the predictive power of QSAR models and to prevent over-fitting phenomenon of classical QSAR models. Our QSAR model could be applied to design new analogues of BCPs with higher antitumor and topoisomerase I inhibitory activity.     

2D transient filtration model for aluminum

A two-dimensional, transient mathematical model representing the behavior of a deep-bed filter was developed. The flow and mass fraction equations are solved using CFX™ commercial code. The rate equation representing the inclusion deposition and re-entrainment is incorporated into a model as a source term of the mass fraction equation. The resistance of the bed is calculated using the pressure drop calculated by the Ergun equation. The model takes into account all the major physical processes occurring during filtration. For each time step, the model calculates the inclusion concentrations remaining in the liquid and deposited on the filter media. It updates the bed porosity and bed particle size as the inclusions deposit. The model can use either an average inclusion size or a discrete inclusion size distribution. It is also possible to assign different densities to different inclusion sizes if an inclusion distribution is used.     

Non-equilibrium cation distribution and enhanced spin disorder in hollow CoFe2O4 nanoparticles

We present magnetic properties of hollow and solid CoFe(2)O(4) nanoparticles that were obtained by annealing of Co(33)Fe(67)/CoFe(2)O(4) (core/shell) nanoparticles. Hollow nanoparticles were polycrystalline whereas the solid nanoparticles were mostly single crystal. Electronic structure studies were performed by photoemission which revealed that particles with hollow morphology have a higher degree of inversion compared to solid nanoparticles and the bulk counterpart. Electronic structure and the magnetic measurements show that particles have uncompensated spins. Quantitative comparison of saturation magnetization (M(S )), assuming bulk Néel type spin structure with cationic distribution, calculated from quantitative XPS analysis, is presented. The thickness of uncompensated spins is calculated to be significantly large for particles with hollow morphology compared to solid nanoparticles. Both morphologies show a lack of saturation up to 7 T. Moreover magnetic irreversibility exists up to 7 T of cooling fields for the entire temperature range (10-300 K). These effects are due to the large bulk anisotropy constant of CoFe(2)O(4) which is the highest among the cubic spinel ferrites. The effect of the uncompensated spins for hollow nanoparticles was investigated by cooling the sample in large fields of up to 9 T. The magnitude of horizontal shift resulting from the unidirectional anisotropy was more than three times larger than that of solid nanoparticles. As an indication signature of uncompensated spin structure, 11% vertical shift for hollow nanoparticles is observed, whereas solid nanoparticles do not show a similar shift. Deconvolution of the hysteresis response recorded at 300 K reveals the presence of a significant paramagnetic component for particles with hollow morphology which further confirms enhanced spin disorder.     

Dynamic crack analysis in 2D elastic solids with the singular edge-based smoothed finite element method

The singular edge-based smoothed finite element method (sES-FEM) is developed for stationary dynamic crack analysis in two-dimensional (2D) elastic solids. The paper aims at providing a better understanding of the dynamic fracture behaviors in linear elastic solids by means of the strain smoothing technique. The strains are smoothed and the system stiffness matrix is performed using the strain smoothing over the smoothing domains associated with the element edges. A two-layer singular five-node crack-tip element is employed while the standard implicit time integration scheme is used for solving the discrete sES-FEM equation system. Dynamic stress intensity factors (DSIFs) are extracted using the domain-form of interaction integrals in terms of the smoothing technique. The normalized DSIFs are compared with reference solutions showing a high accuracy of the sES-FEM. (© 2012 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

The superconducting fluctuation optical conductivity of iron-based superconductors

The European Physical Journal B - The physical properties of a quantum many-body system can, in principle, be determined by diagonalizing the respective Hamiltonian, but the dimensions of its...