Towards Efficient Full Pose Omnidirectionality with Overactuated MAVs

Omnidirectional MAVs are a growing field, with demonstrated advantages for aerial interaction and uninhibited observation. While systems with complete pose omnidirectionality and high hover efficiency have been developed independently, a robust system that combines the two has not been demonstrated to date. This paper presents VoliroX: a novel omnidirectional vehicle that can exert a wrench in any orientation while maintaining efficient flight configurations. The system design is presented, and a 6 DOF geometric control that is robust to singularities. Flight experiments further demonstrate and verify its capabilities.Comment: 10 pages, 6 figures, ISER 2018 conference submissio

Very High Cycle Corrosion Fatigue Study of the Collapsed Polcevera Bridge, Italy

A possible scenario is proposed to put into evidence how the combined effect of fatigue at very high number of cycles and corrosion could have been responsible for the failure of one of the strands and the subsequent collapse of the so-called balanced system of the Polcevera Bridge designed by Morandi. The analysis accounts for an actual estimation of the heavy-lorry traffic and load spectrum, as well as for the European Standards prescription for the fatigue damage accumulation assessment. In addition, the effective construction phases of the viaduct are considered. The structural analysis is carried out by means of analytical models, in order to simplify the structure complexity without prejudice to the description of the most relevant aspects of the structural behavior. The main purpose is to warn the scientific community and the public administrations that the combined effects of low-amplitude fatigue and corrosion can be dangerously underestimated, and that the existing assets of 20th century bridges deserve special attention in this respect

Cap rock efficiency of geothermal systems in fold-and-thrust belts: Evidence from paleo-thermal and structural analyses in Rosario de La Frontera geothermal area (NW Argentina)

Cap rock characterization of geothermal systems is often neglected despite fracturing may reduce its efficiency and favours fluid migration. We investigated the siliciclastic cap rock of Rosario de La Frontera geothermal system (NW Argentina) in order to assess its quality as a function of fracture patterns and related thermal alteration. Paleothermal investigations (XRD on fine-grained fraction of sediments, organic matter optical analysis and fluid inclusions on veins) and 1D thermal modelling allowed us to distinguish the thermal fingerprint associated to sedimentary burial from that related to fluid migration. The geothermal system is hosted in a Neogene N-S anticline dissected by high angle NNW- and ENE-striking faults. Its cap rock can be grouped into two quality categories: • rocks acting as good insulators, deformed by NNW–SSE and E–W shear fractures, NNE-SSW gypsum- and N-S-striking calcite-filled veins that developed during the initial stage of anticline growth. Maximum paleo-temperatures (< 60 °C) were experienced during deposition to folding phases.• rocks acting as bad insulators, deformed by NNW-SSE fault planes and NNW- and WNW-striking sets of fractures associated to late transpressive kinematics. Maximum paleo-temperatures higher than about 115 °C are linked to fluid migration from the reservoir to surface (with a reservoir top at maximum depths of 2.5 km) along fault damage zones.This multi-method approach turned out to be particularly useful to trace the main pathways of hot fluids and can be applied in blind geothermal systems where either subsurface data are scarce or surface thermal anomalies are lacking.Fil: Maffucci, R.. Universita Degli Studi Della Tuscia; Italia. Universita Degli Studi Roma Tre; ItaliaFil: Corrado, Sveva. Universita Degli Studi Roma Tre; ItaliaFil: Aldega, L.. Instituto de Investigaciones Universitarias Roma la Sapienza; ItaliaFil: Bigi, S.. Instituto de Investigaciones Universitarias Roma la Sapienza; ItaliaFil: Chiodi, Agostina Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones en Energía no Convencional. Universidad Nacional de Salta. Facultad de Ciencias Exactas. Departamento de Física. Instituto de Investigaciones en Energía no Convencional; ArgentinaFil: Di Paolo, L.. Eni E&P Division; ItaliaFil: Giordano, G.. Universita Degli Studi Roma Tre; ItaliaFil: Invernizzi, C.. Universita Degli Di Camerino; Itali

Response and relapse rates after treatment with long-acting somatostatin analogs in multifocal or recurrent type-1 gastric carcinoids : a systematic review and meta-analysis

Background: Type-1 gastric neuroendocrine tumors represent a recurring disease and long-acting somatostatin analogs can inhibit both gastrin release and endocrine cell proliferation. The efficacy and timing of this treatment are still unclear. We performed a systematic review of the literature to clarify the role of somatostatin analog treatment in type-1 gastric neuroendocrine tumors. Methods: A computerized literature search was performed using relevant keywords to identify all the pertinent articles published in the last 15 years. Results: Eight studies were included in this systematic review on somatostatin analogs in type-1 gastric neuroendocrine tumors. A complete response rate ranged from 25\u2013100%. When only the six prospective studies were considered, no significant heterogeneity was observed, and the pooled cumulative complete response rate was 84.5% (confidence interval 73.8\u201392.8). Three studies evaluated the type-1 gastric neuroendocrine tumor recurrence, with a cumulative relapse rate of 30.2% (confidence interval 13.1\u201350.6) after 34 months. Conclusion: Somatostatin analogs, namely lanreotide and octreotide, have an excellent response rate, with a good safety profile in selected type-1 gastric neuroendocrine tumors, which cannot be safely managed by endoscopic follow-up or resection due to multiple or frequently recurring disease. After therapy discontinuation, the cumulative relapse rate observed after a median 34-month follow-up was relatively high (30.2%)

Un lettore quattrocentesco della Commedia : Martino Paolo Nibia e il commento al primo canto dell'Inferno

Analisi di alcune chiose al primo canto dell'Inferno tratte dal commento di Martino Paolo Nibia (Nidobeato) alla Commedia di Dante, pubblicato a Milano nel 1478

Entanglement of two blocks of spins in the critical Ising model

We compute the entropy of entanglement of two blocks of L spins at a distance d in the ground state of an Ising chain in an external transverse magnetic field. We numerically study the von Neumann entropy for different values of the transverse field. At the critical point we obtain analytical results for blocks of size L=1 and L=2. In the general case, the critical entropy is shown to be additive when d goes to infinity. Finally, based on simple arguments, we derive an expression for the entropy at the critical point as a function of both L and d. This formula is in excellent agreement with numerical results.Comment: published versio

3D Bioprinting of Gelatin–Xanthan Gum Composite Hydrogels for Growth of Human Skin Cells

In recent years, bioprinting has attracted much attention as a potential tool for generating complex 3D biological constructs capable of mimicking the native tissue microenvironment and promoting physiologically relevant cell–cell and cell–matrix interactions. The aim of the present study was to develop a crosslinked 3D printable hydrogel based on biocompatible natural polymers, gelatin and xanthan gum at different percentages to be used both as a scaffold for cell growth and as a wound dressing. The CellInk Inkredible 3D printer was used for the 3D printing of hydrogels, and a glutaraldehyde solution was tested for the crosslinking process. We were able to obtain two kinds of printable hydrogels with different porosity, swelling and degradation time. Subsequently, the printed hydrogels were characterized from the point of view of biocompatibility. Our results showed that gelatin/xanthan-gum bioprinted hydrogels were biocompatible materials, as they allowed both human keratinocyte and fibroblast in vitro growth for 14 days. These two bioprintable hydrogels could be also used as a helpful dressing material