[en] We present an experimental approach to the study of the chirality of three CM2 meteorite solid samples by direct measurement of the optical activity (circular birefringence; CB). The measurements are based on transmission two modulator generalized ellipsometry in conjuction with microscope optics to map the CB of the samples. In spite of the complexity of such optical analysis, these first results indicate the presence of optically active areas in the meteorite solid matrix. In the case of the Murchison sample the statistics of the CB mapping shows a bimodal distribution with a bias to negative CB values. The composition of the active areas probably corresponds to serpentines and other poorly identified phyllosilicate phases. The results are compatible with the hypothesis that in a mineral-based scenario for the origin of life a CB sign bias in the chiral fractures originated by mechanical and flow shear gradients on clays could be later transferred to the reactions of the absorbed organic compounds.

[en] The final choice as the photomultiplier solution for both the LHCb Pre-Shower (PS) and the Scintillator Pad Detector (SPD) are the R7600-00-M64MOD Hamamatsu 64 channel photomultiplier tubes (MaPMT). A total of 220 units have been purchased to the manufacturer and around 100 units, the part corresponding to the SPD, have been characterized at the photon detection test bench facility in University of Barcelona (UB) high energy physics group laboratory. There, the crucial features of the tubes such as linearity, gain, channel cross-talk and anode uniformity of response have been measured to ensure the compliance with the specifications agreed with the manufacturer

[en] Amorphous Fe-Cu-Nb-Si-B ribbons were annealed between 525 and 700 C. Crystallization processes were studied using X-ray diffraction and Moessbauer spectroscopy so as to follow the effect of crystallite size, alloy composition and phase constitution on the magnetic properties. ((orig.))

[en] Chiral lagrangians describing the interactions of Goldstone bosons in a theory possessing spontaneous symmetry breaking are effective, non-renormalizable field theories in four dimensions. Yet, in a momentum expansion one is able to extract definite, testable predictions from perturbation theory. These techniques have yielded in recent years a wealth of information on many problems where the physics of Goldstone bosons plays a crucial role, but theoretical issues concerning chiral perturbation theory remain, to this date, poorly treated in the literature. We present here a rather comprehensive analysis of the regularization and renormalization ambiguities appearing in chiral perturbation theory at the one-loop level. We discuss first on the relevance of dealing with tadpoles properly. We demonstrate that Ward identities severely constrain the choice of regulators to the point of enforcing unique, unambiguous results in chiral perturbation theory at the one-loop level for any observable which is free from chiral logarithmic divergences. We comment on the physical implications of these results and on several possible regulating methods that may be of use for some applications. ((orig.))

[en] The calorimeter front-end electronics of the LHCb experiment will be located in a region, which is not protected from radiation. Therefore, all the electronics must be qualified to stand some defined radiation levels. The procedure, measurements and results of an irradiation test for every component of the very front-end SPD detector, which is part of the LHCb calorimeter are presented here. All the tested components, except a custom made ASIC, are commercially available

[en] This work focussed on the deposition of wear-resistant and corrosion-resistant WC-25Co cermet powders on carbon steel and aluminium (Al7075-T6) substrates by cold gas spraying (CGS). The unique combination of mechanical, physical and chemical properties of WC-Co cermets has led to their widespread use for the manufacture of wear-resistant parts. X-ray diffraction tests were run on the powder and coatings to determine possible phase changes during the spraying process. The bonding strength of the coatings was measured by adhesion tests (ASTM C633-08). The sliding (ASTM G99-04) and abrasive (ASTM G65-00) wear resistance of the coatings were also studied. Corrosion resistance was determined by electrochemical measurements and salt fog spray tests (ASTM B117-03). CGS achieved thick, dense and hard WC-25Co coatings on both aluminium alloy Al7075-T6 and carbon steel substrates, with excellent tribological and electrochemical properties. We thus conclude that this method is very competitive compared with conventional thermal spraying techniques, giving thick, dense and hard coatings on both aluminium alloy Al7075-T6 and carbon steel substrates, with excellent tribological and electrochemical properties.

[en] The growth of platinum thin film by rf magnetron sputtering on SrTiO₃(0 0 1) substrates for oxide based devices was investigated. Platinum films grown at temperatures higher than 750 °C were epitaxial ([1 0 0]Pt(0 0 1)//[1 0 0]STO(0 0 1)), whereas at lower temperatures Pt(1 1 1) films were obtained. The surface morphology of the Pt films showed a strong dependence on the deposition temperature as was revealed by atomic force microscopy (AFM). At elevated temperatures there is a three-dimensional (3D) growth of rectangular atomically flat islands with deep boundaries between them. On the other hand, at low deposition temperatures, a two-dimensional (2D) layered growth was observed. The transition from 2D to 3D growth modes was observed that occurs for temperatures around 450 °C. The obtained epitaxial thin films also formed an atomically sharp interface with the SrTiO₃(0 0 1) substrate as confirmed by HRTEM.

[en] Two-dimensional lattice-gas models with attractive interactions and particle-conserving hopping dynamics under the influence of a very large external electric field along a principal axis are studied in the case of off-critical densities. They describe the corresponding nonequilibrium first-order phase transitions, evaluate coexistence and spinodal lines, and make some comparisons with experimental observations on fast ionic conductors

[en] A geometric proof is given of Lee Hwa Chung's theorem for regular Hamiltonian systems, which identifies all the possible differential forms left invariant by the dynamics. Applications of this theorem in the area of canonical transformations are also remarked in a purely geometrical context

[en] Tables are given of total cross sections as well as first and second transport cross sections for elastic scattering of electrons with kinetic energies from 100 eV to 1 GeV by neutral atoms with atomic number Z = 1 to 92. With the information given in the present tables, accurate Monte Carlo simulations of electron multiple elastic scattering can be easily performed. The tabulated cross sections have been calculated by using the Dirac partial wave method with screened potentials obtained from Dirac-Hartree-Fock atomic electron densities. Exchange effects are introduced by means of the local approximation of Furness and McCarthy. Nuclear size effects are accounted for in the Born approximation by using Helm''s nuclear form factor. 28 refs., 2 figs., 1 tab