Analytic continuation by averaging Pad\'e approximants

The ill-posed analytic continuation problem for Green's functions and self-energies is investigated by revisiting the Pad\'{e} approximants technique. We propose to remedy the well-known problems of the Pad\'{e} approximants by performing an average of several continuations, obtained by varying the number of fitted input points and Pad\'{e} coefficients independently. The suggested approach is then applied to several test cases, including Sm and Pr atomic self-energies, the Green's functions of the Hubbard model for a Bethe lattice and of the Haldane model for a nano-ribbon, as well as two special test functions. The sensitivity to numerical noise and the dependence on the precision of the numerical libraries are analysed in detail. The present approach is compared to a number of other techniques, i.e. the non-negative least-square method, the non-negative Tikhonov method and the maximum entropy method, and is shown to perform well for the chosen test cases. This conclusion holds even when the noise on the input data is increased to reach values typical for quantum Monte Carlo simulations. The ability of the algorithm to resolve fine structures is finally illustrated for two relevant test functions.Comment: 10 figure

Lattice dynamics of palladium in the presence of electronic correlations

We compute the phonon dispersion, density of states, and the Gr\"uneisen parameters of bulk palladium in the combined density functional theory (DFT) and dynamical mean-field theory (DMFT). We find good agreement with experimental results for ground state properties (equilibrium lattice parameter and bulk modulus) and the experimentally measured phonon spectra. We demonstrate that at temperatures $T \lesssim 20~K$ the phonon frequency in the vicinity of the Kohn anomaly, $\omega_{T1}({\bf q}_{K})$, strongly decreases. This is in contrast to DFT where this frequency remains essentially constant in the whole temperature range. Apparently correlation effects reduce the restoring force of the ionic displacements at low temperatures, leading to a mode softening.Comment: minor revision

CREEP OF CRACKED POLYMER FIBER REINFORCED CONCRETE UNDER SUSTAINED TENSILE LOADING

In fiber reinforced concrete (FRC), fibers are added to the fresh concrete mix in order to improve the residual tensile strength, the toughness and/or durability of a concrete element. Cur- rently, structural applications remain relatively scarce as the time-dependent behavior of FRC is still poorly understood. This paper reports the first results of an experimental campaign regarding the creep of cracked polymer FRC. In the test setup, cylindrical, notched FRC specimens are considered. The concrete is reinforced with structural polymeric fibers for use in load-bearing applications. In a first step, the material is characterized according to the European Standard EN14651. Secondly, the samples are precracked to localize the creep deformations and to monitor the crack growth in time. The samples are subjected to a sustained tensile load, whereby different load levels with respect to the individual residual strength are considered. The results of the first months of creep loading will be detailed and discussed in the paper

ENVIRONMENTAL MONITORING MANAGEMENT OF WASTE FROM LARGE EXCAVATIONS DUE TO INFRASTRUCTURE BUILDINGS

Abstract. Large infrastructure building like the Florence Railway Station designed for high-speed rails requires a proper management of the huge quantity of waste originating from excavation activities. Such waste amounts require large areas for disposals, making abandoned areas or exhausted quarries and mines ideal sites for hosting the excavated wastes.A rectangular area of 500×70m delimiting the railway station has been excavated in two steps causing the removal of a 10m-thick soil layer per step: excavated earth and rocks would then be used for the environmental restoration of an area of 400×350m located near a former exhausted lignite quarry) in the proximity of the Santa Barbara village near Cavriglia (Arezzo).The Tuscan Regional Environmental Agency (ARPAT) have been involved in monitoring both the terrain transportation and disposals' operations according to the approved management plan: the Environmental Regional Information System Office (SIRA) was asked to evaluate volume balancing between all the waste management cycle, with included: (a) waste extraction from railway station site building, and (b) waste disposal final destination (exhausted Santa Barbara lignite quarry).Terrestrial Laser Scanner (TLS), Simultaneous Localization and Mapping System (SLAM) systems and Remotely Piloted Aircraft Systems (RPAS) surveys have been used to track earth and rocks excavation and disposal activities in the aforementioned sites: while RPAS systems cannot be used in underground site surveys, their usage must be recommended in open space surveys due to the ese of use if sub-centimetric precisions are not required.Multiple TLS scans alignment can result in a quite challenging task if automatic alignment software is not available, requiring manual rough alignment's operations that can be very time consuming: two open-source solutions based on different algorithms have been evaluated.The selected survey technologies – RPAS, TLS, SLAM – have shown a great potential in earth and rocks monitoring: each technology has its own strengths and weakness, which can vary on the basis of both hardware and software technical progresses

Commentary: Novel interventions in complex aortic disease: A perfect storm to “B-SAFER”

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Contribution to the vascular flora of Papasidero (north-western Calabria, Italy)

A floristic survey of the Papasidero municipality (54.65 km2) was carried out from 2008 to 2011, allowing us to list 580 specific and infraspecific taxa (567 verified by us), belonging to 353 genera and 89 families. Several species are rather interesting from a phytogeographic and/or conservation point of view. 14 exotic species were also recorded, 10 of which are considered invasive in the regional flora. The most represented families are Asteraceae (66 taxa), Fabaceae (56), Lamiaceae (40), Poaceae (31), while most represented genera are Trifolium (11), Euphorbia and Ophrys (9), Lathyrus and Geranium (8). Biological and chorological spectra show a clear dominance of Hemicriptophytes and Mediterranean elements respectively, as one can expect based on the climatic conditions of the area at issues

Performances of infrared emitters applied to the porous thin materials drying

Drying of solids is one of the oldest and most common unit operations found in diverse processes. In this paper the drying of hygroscopic textile materials is discussed. The authors have previously investigated the drying kinetic of different fabrics dried by a hot air jet. In this paper a comparison between the convective and electric IR drying is made. In particular two fabrics with fibers which show a different hygroscopic behaviour are analysed: wool and cellulose/cotton. Unlike the convective drying, IR drying is weakly affected by the radiation properties and by the hygroscopic behaviour of the two fabrics. This is likely due to a better diffusion of the heat flux, which is constant over the entire drying surface in the case of IR heating, and produces unexpected results on the nondimensional kinetic parameter (characteristic curve). Wool shows a complete different characteristic curve if dried with IR or with convective flow. The better performances have been reached with MW emitter, but it has been observed that this advantage decreases with the distance of the source from the surface to be dried