Environmental evaluation of Surface Mounted Devices (SMD)

We evaluated the comparative reliability of solder interconnections used for Leadless Chip Carriers (LCCs), Meaded, and flat-pack hybrid microcircuits mounted on FR-4 glass epoxy printed wiring boards (PWBs). The board assemblies, with solder attached microcircuits, were repeatedly thermal cycled from - 65 to +125{degrees}C. We recognize that this temperature range far exceeds most testing of assemblies. The purposes of these tests were to evaluate worst-case conditions and to obtain comparative information. Identical PWB assemblies, using these three component types, were subjected to both thermal shock testing (1 cycle every 42 minutes) and temperature cycle testing (1 cycle every 3 hours). The double testing evaluated the differences in stress application and evaluated the potential of replacing slow transition, expensive temperature cycle testing (which has been an industry standard for years) with the much more rapid thermal shock testing

Continued Use Of Drugs And Working Conditions Among Truck Drivers

Few studies have been conducted on truck drivers with regard to their health problems, especially their drug consumption profile. This study aimed to determine the continuous use of drugs and to identify use-related professional characteristics among this category. A cross-sectional study was carried out with truck drivers parked at the sorting yard of the, Port of Paranaguá, Paraná. An interview to obtain socioeconomic data, data on health problems, working conditions and continued use of medication was performed. Of the drivers evaluated (n = 665), 21.1% reported a continuous use of some medication, mainly captopril (10.7%), metformin (10.3%), omeprazole (6.2%) and simvastatin (6.2%). Drivers with 16 or more years of professional experience (Prevalence Ratio [PR] 1.67; Confidence Interval [CI] 95% 1.11-2.51), truck owners (PR 1.38; CI 95% 1.03-1.86) and without formal labor contract (PR 1.49; CI 95% 1.11-2.00) had a higher prevalence of continuous use of medication. We noted that some working conditions play an important role in the continuous use of drugs by truck drivers. © 2016, Associacao Brasileira de Pos - Graduacao em Saude Coletiva. All rights reserved.21123769377

Circular orbits of corotating binary black holes: comparison between analytical and numerical results

We compare recent numerical results, obtained within a ``helical Killing vector'' (HKV) approach, on circular orbits of corotating binary black holes to the analytical predictions made by the effective one body (EOB) method (which has been recently extended to the case of spinning bodies). On the scale of the differences between the results obtained by different numerical methods, we find good agreement between numerical data and analytical predictions for several invariant functions describing the dynamical properties of circular orbits. This agreement is robust against the post-Newtonian accuracy used for the analytical estimates, as well as under choices of resummation method for the EOB ``effective potential'', and gets better as one uses a higher post-Newtonian accuracy. These findings open the way to a significant ``merging'' of analytical and numerical methods, i.e. to matching an EOB-based analytical description of the (early and late) inspiral, up to the beginning of the plunge, to a numerical description of the plunge and merger. We illustrate also the ``flexibility'' of the EOB approach, i.e. the possibility of determining some ``best fit'' values for the analytical parameters by comparison with numerical data.Comment: Minor revisions, accepted for publication in Phys. Rev. D, 19 pages, 6 figure

Resolution of dark matter problem in f(T) gravity

In this paper, we attempt to resolve the dark matter problem in f(T) gravity. Specifically, from our model we successfully obtain the flat rotation curves of galaxies containing dark matter. Further, we obtain the density profile of dark matter in galaxies. Comparison of our analytical results shows that our torsion-based toy model for dark matter is in good agreement with empirical data-based models. It shows that we can address the dark matter as an effect of torsion of the space.Comment: 14 pages, 3 figure

Current status of turbulent dynamo theory: From large-scale to small-scale dynamos

Several recent advances in turbulent dynamo theory are reviewed. High resolution simulations of small-scale and large-scale dynamo action in periodic domains are compared with each other and contrasted with similar results at low magnetic Prandtl numbers. It is argued that all the different cases show similarities at intermediate length scales. On the other hand, in the presence of helicity of the turbulence, power develops on large scales, which is not present in non-helical small-scale turbulent dynamos. At small length scales, differences occur in connection with the dissipation cutoff scales associated with the respective value of the magnetic Prandtl number. These differences are found to be independent of whether or not there is large-scale dynamo action. However, large-scale dynamos in homogeneous systems are shown to suffer from resistive slow-down even at intermediate length scales. The results from simulations are connected to mean field theory and its applications. Recent work on helicity fluxes to alleviate large-scale dynamo quenching, shear dynamos, nonlocal effects and magnetic structures from strong density stratification are highlighted. Several insights which arise from analytic considerations of small-scale dynamos are discussed.Comment: 36 pages, 11 figures, Spa. Sci. Rev., submitted to the special issue "Magnetism in the Universe" (ed. A. Balogh

Quantum walks: a comprehensive review

Quantum walks, the quantum mechanical counterpart of classical random walks, is an advanced tool for building quantum algorithms that has been recently shown to constitute a universal model of quantum computation. Quantum walks is now a solid field of research of quantum computation full of exciting open problems for physicists, computer scientists, mathematicians and engineers. In this paper we review theoretical advances on the foundations of both discrete- and continuous-time quantum walks, together with the role that randomness plays in quantum walks, the connections between the mathematical models of coined discrete quantum walks and continuous quantum walks, the quantumness of quantum walks, a summary of papers published on discrete quantum walks and entanglement as well as a succinct review of experimental proposals and realizations of discrete-time quantum walks. Furthermore, we have reviewed several algorithms based on both discrete- and continuous-time quantum walks as well as a most important result: the computational universality of both continuous- and discrete- time quantum walks.Comment: Paper accepted for publication in Quantum Information Processing Journa

Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results