Autoionizing decay of H 2 doubly excited states by using xuv-pump-infrared-probe schemes with trains of attosecond pulses

We present a theoretical study of H2 ionization by a pump-probe scheme consisting on an attosecond pulse train (APT) and a near-infrared (IR) pulse.We focus on the autoionization dynamics of the first series of resonant states of the molecule, the Q1 doubly excited states. The APT central frequency is tuned to populate the 1∑ + u resonant states. The trace of autoionization is clearly visible in the two-dimensional (2D) proton-electron coincidence spectra and in the proton kinetic energy spectra. The dynamics of the autoionization process is clearly visible in the movie obtained by plotting the 2D spectrum as a function of the time delay between the APT and IR pulses. An analysis of the final symmetries ∑g and ∑u allows us to track the origin of the different structuresThis work was partially supported by the MICINN Projects No. FIS2010- 15127, No. ACI2008-0777, and No. CSD 2007-00010, the ERA-Chemistry Project No. PIM2010EEC-00751, the European grants MC-ITN CORINF and MC-RG ATTOTREND, the European COST Action CM0702, and the Advanced Grant of the European Research Council XCHEM 29085

Risk management of bored piling construction on sandy soils with real-time cost control

UIDP/GEO/04035/2020In a global society, in which geotechnical projects are increasingly designed in a country other than the one where construction takes place, geotechnical risk management must be extended to cover infrastructure works, which are smaller than dams and tunnels, for example, since there is a significant impact on works budget imponderables. Therefore, a risk management methodology based on the likelihood of the occurrence of certain events and their economic consequences is proposed, which is applicable to bored piles (Kelly drilled) in coarse soils, easy to use, and simple to implement since the initial stage of construction. Of 12 case studies of construction works involving bored piles (Kelly drilled) carried out in Luanda (Angola), two selected examples involving the proposed risk methodology on sandy soil layers with interbedded clays are discussed. Subsequently, whether the overall foundation contract budget is affected by assessed risk is determined, and what influence it has on the budget in the light of mitigating factors and associated real costs. This method intended to encourage the adaptation of sustainable risk management in bored piles construction by the site project managers, involving risk analysis concurrently with budgetary review. Though the level of assessed technical risk may be acceptable, overall costs associated with the contract in question may not be acceptable.publishersversionpublishe

Preliminary Study of Contact Modelling the Interface between User Skin and Wearable Equipment

Com o apoio RAADRI.For a suitable development of wearable equipment, it is important to take in consideration comfort issues, and the simulation of the contact between is the adequate tool. To simulate the contact a preliminary study an empirical models were developed using non-linear fitting. The data was collected using compression and decompression tests using different indenter’s diameters in one subject

Influence of cross section geometry on the confinement of reinforced concrete columns with CFRP composites

Comunicação apresentada em International Symposium Polymers in Concrete (ISPIC 2006), Guimarães, 2006Confinement effectiveness of externally bonded FRP jackets depends on different parameters namely type of concrete, steel reinforcement, FRP jacket stiffness (type of FRP, number of plies and design of wrap), shape of cross section, radius of corners for non-circular sections, and loading conditions. In order to investigate the effect of some of these parameters on the axial behavior of columns under compression and to quantify the level of confinement exerted on the concrete core, an experimental program has been developed. The experimental research consisted of a sequence of axial compressive tests on cylinders and square prisms. Prisms were divided into three representative groups: sharpedged sections and sections with rounded corners with corner radii equal to either 20mm or 38mm. The results presented in this paper are for the columns which were wrapped with two plies of unidirectional carbon fibers

Molecular resolvent-operator method: Electronic and nuclear dynamics in strong-field ionization

We present an extension of the resolvent-operator method (ROM), originally designed for atomic systems, to extract differential photoelectron spectra (in photoelectron- and nuclear-kinetic energy) for diatomic molecules interacting with strong, ultrashort laser fields in the single active electron approximation. The method is applied to the study of H2+ photodissociation and photoionization by femtosecond laser pulses in the XUV-IR frequency range. In particular, the method is tested (i) in the perturbative regime, for few-photon absorption and bound-bound electronic transitions, and (ii) in the strong-field regime, in which multiphoton absorption and tunneling are present. In the latter case, we show how the differential ROM allows one to track the transition between both regimes. We also analyze isotopic effects by comparing the dynamics of H2+ and D2+ ionization for different pulses. © 2014 American Physical Society.This work was accomplished with an allocation of computer time from Mare Nostrum BSC and CCC-UAM and was partially supported by the MICINN Projects No. FIS2010- 15127 and No. CSD 2007-00010, ERA-Chemistry Project No. PIM2010EEC-00751, the European grants No. MC-ITN CORINF and No. MC-RG ATTOTREND, the European COST Action No. CM0702, and European Research Council Advanced Grant No. XCHEM 290853. R.E.F.S. acknowledges a Ph.D. contract from ITN CORINF and Grant No. SFRH/BD/84053/2012 from the Portuguese government. P.R. acknowledges a Juan de la Cierva contract grant from the Spanish MICIN

Correlated electron and nuclear dynamics in strong field photoionization of H2+

We present a theoretical study of H2+ ionization under strong IR femtosecond pulses by using a method designed to extract correlated (2D) photoelectron and proton kinetic energy spectra. The results show two distinct ionization mechanisms—tunnel and multiphoton ionization—in which electrons and nuclei do not share the energy from the field in the same way. Electrons produced in multiphoton ionization share part of their energy with the nuclei, an effect that shows up in the 2D spectra in the form of energy-conservation fringes similar to those observed in weak-field ionization of diatomic molecules. In contrast, tunneling electrons lead to fringes whose position does not depend on the proton kinetic energy. At high intensity, the two processes coexist and the 2D plots show a very rich behavior, suggesting that the correlation between electron and nuclear dynamics in strong field ionization is more complex than one would have anticipatedThis work was accomplished with an allocation of computer time from Mare Nostrum BSC and CCC-UAM, and was partially supported by the MICINN Projects No. FIS2010-15127, No. ACI2008-0777, and No. CSD 2007-00010, the ERA-Chemistry Project No. PIM2010EEC-00751, the European Grants No. MCITN CORINF and No. MC-RG ATTOTREND, the European COST Action CM0702, and the Advanced Grant of the European Research Council, Grant No. XCHEM 290853. R. E. F. S. acknowledges a Ph.D. contract from ITN CORINF. P. R. acknowledges a Juan de la Cierva contract grant from MICIN

Contribution of an environmental monitoring system to evaluate the potential effect of urban air pollution

The growth of the world?s population has been followed by the increase of residents living in urban areas, which very often results in additional pressures concerning space, ecosystems, infrastructures, facilities and the way of life. The impact of pollutants, emitted into the atmosphere, on materials is enormous and could be irreversible. The effects of the air pollution in façades and on the structural systems lead to unexpected costs for the buildings maintenance and may be avoided if pollution monitoring systems exists. This work presents a methodology to evaluate, on a regular basis, the potential impact of air pollution on historical buildings. It uses a monitoring system to collect samples of particulate matter (PM10 and PM2.5), particulate matter concentration levels and weather parameters. It is possible to act, in time, for the preservation and protection of this historical heritage by joining all of these data. This methodology could complement the studies of the environmental impact assessments on the historical buildings from the outdoor air pollution sources and contributes to the preservation and protection of the historical buildings. This work is being applied in the Portuguese midsized city of Vila Real, where the urban pollution assessment and their effects in urban historical buildings was considered the main goal.(undefined