Stochastic model predictive control of LPV systems via scenario optimization

A stochastic receding-horizon control approach for constrained Linear Parameter Varying discrete-time systems is proposed in this paper. It is assumed that the time-varying parameters have stochastic nature and that the system's matrices are bounded but otherwise arbitrary nonlinear functions of these parameters. No specific assumption on the statistics of the parameters is required. By using a randomization approach, a scenario-based finite-horizon optimal control problem is formulated, where only a finite number M of sampled predicted parameter trajectories (‘scenarios') are considered. This problem is convex and its solution is a priori guaranteed to be probabilistically robust, up to a user-defined probability level p. The p level is linked to M by an analytic relationship, which establishes a tradeoff between computational complexity and robustness of the solution. Then, a receding horizon strategy is presented, involving the iterated solution of a scenario-based finite-horizon control problem at each time step. Our key result is to show that the state trajectories of the controlled system reach a terminal positively invariant set in finite time, either deterministically, or with probability no smaller than p. The features of the approach are illustrated by a numerical example

Corrosion Resistance Behaviour of recycled AlSi10Mg alloy: Surface Morphology and Acoustic Emission Investigation

The corrosion resistance behaviour of recycled AlSi10Mg alloy prepared using Selective Laser Melting (SLM) process is investigated. The specimens are exposed to salt solution attack (5% NaCl) atomized in uniform droplets, inside a controlled Salt Spray Test (SST) chamber for 1000 h. The surface morphology of the specimens exposed to different predefined exposure times (0 h, 6 h, 48 h, 168 h, 480 h and 1000 h) are investigated under Scanning Electron Microscope (SEM). The SEM micrographs shows the salient features of the corrosion attack such as the formation both of pits and corrosion products on samples surface in different exposure times in the SST chamber. Similarly, the Acoustic Emission (AE) signals generated during the corrosion process are recorded for the different exposure times. The AE waveforms are studied using advanced waveform processing techniques. The waveforms, in their time-frequency domain, provide detailed information on the characteristic features of the acoustic source. The different AE sources have been characterized from the time-frequency analysis of the waveforms

Imaging of biliary involvement in sarcoidosis: Computed tomography, magnetic resonance cholangiopancreatography, and gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging findings

Sarcoidosis is a multisystem disease usually affecting the chest, hilar lymph nodes, and lungs, but can potentially involve any organ; therefore, its clinical presentation may vary. Hepato-biliary involvement is rare, and typically asymptomatic; however, it can lead to cirrhosis, and may require liver transplantation. In this report, we present a rare case of a patient affected by sarcoidosis with hepatobiliary involvement. He presented to our hospital complaining of dyspnea triggered by moderate efforts and oppressive thoracic discomfort. Chest X-ray showed multiple bilateral nodular opacities and enlargement of both hilar regions, confirmed by a subsequent total-body computed tomography scan and positron emission tomography, which also revealed cardiac, splenic, and hepatic involvement. Liver function was studied via gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging, and magnetic resonance cholangiopancreatography (MRCP) was also performed. The diagnosis of sarcoidosis was finally achieved via liver biopsy, revealing non-necrotizing granulomas in the periportal space. The patient was treated with prednisone per os, with regression of all lesions at all levels. Although other cases of biliary sarcoidosis have been described, this report provides a complete image set of Gd-EOB-DTPA-enhanced magnetic resonance and MRCP images that is lacking in the English literature, and which may be useful for diagnosis

DIC analysis of mechanical response of tooth aligners under simulated swallowing acts

In this work, the mechanical and deformation behavior of clear Polyethylene Terephthalate-glycol (PET-g) aligners, under cyclic loading was investigated using a full-field optical technique: the Digital Image Correlation. In particular, the PET-g aligners thermoformed from 0.88 mm thick discs, were subjected to cyclic compression tests for 13000 load cycles from 0 to 50 N in the atmospheric environment (~25°C). This number of cycles was chosen because it simulates, on average, the intraoral load associated with the swallowing acts that an aligner is subjected to during the time of use of 1 week. At the same time, the results from the analysis of hysteresis loops obtained by the DIC technique were compared with those obtained by the testing machine. The mechanical response of clear aligners was evaluated in terms of maximum displacement, energy loss and relative stiffness along the load direction to seven different stages of the 13000 load cycles. A comparable trend was found between the measurements obtained by Digital Image Correlation analysis and the analysis of the hysteresis loops obtained from the cyclic compression tests. Furthermore, the morphological features of the PET-g aligner at the end of the tests were analyzed by optical microscopy (OM). The OM analyses showed that thesurface of PET-g aligner was affected by morphological variations such as high depressions and cracks

Considerations on the choice of experimental parameters in residual stress measurements by hole-drilling and ESPI

Residual stresses occur in many manufactured structures and components. Great number of investigations have been carried out to study this phenomenon. Over the years, different techniques have been developed to measure residual stresses; nowadays the combination of Hole Drilling method (HD) with Electronic Speckle Pattern Interferometry (ESPI) has encountered great interest. The use of a high sensitivity optical technique instead of the strain gage rosette has the advantage to provide full field information without any contact with the sample by consequently reducing the cost and the time required for the measurement. The accuracy of the measurement, however, is influenced by the proper choice of several parameters: geometrical, analysis and experimental. In this paper, in particular, the effects of some of those parameters are investigated: misknowledgment in illumination and detection angles, the influence of the relative angle between the sensitivity vector of the system and the principal stress directions, the extension of the area of analysis and the adopted drilling rotation speed. In conclusion indications are provided to the scope of optimizing the measurement process together with the identification of the major sources of errors that can arise during the measuring and the analysis stages

METRO - The role and future perspectives of Cohesion Policy in the planning of Metropolitan Areas and Cities. Annex II: The role of Metropolitan areas within the EU cohesion policy

This Annex to the final Report presents and discusses in a comparative manner the evidence collected in the nine case studies that have been explored in the framework of the ESPON Targeted Analysis METRO – The role and future perspectives of cohesion policy in the planning of Metropolitan Areas and Cities (Annexes III to XI). More in detail, the document synthesizes and compares the information collected by the various research teams through the application of the project’s analytical protocol and as a consequence of their continuous interaction with the respective stakeholders. The report is organised following the three main policy questions that have been driving the analysis: PQ1 | What role do metropolitan areas and cities play in the development, management and implementation of the European Union (EU) cohesion policy? PQ2 | What is the added value of the EU cohesion policy in the planning and implementation of metropolitan policies? PQ3 | What role does the EU cohesion policy play in consolidating metropolitan governance and cooperation? These questions are answered through the comparative analysis and assessment of the territorial and institutional contexts in which the nine stakeholders involved in the projects are active: Metropolitan City of Turin (CMTo), Barcelona Metropolitan Area (AMB), Lisbon Metropolitan Area (LMA), Brno Metropolitan Area (BMA), Metropolitan Area of Gdańsk-Gdynia-Sopot (MAG), Metropolitan City of Florence (CMFi), Métropole de Lyon (MdL), Brussels-Capital Region (BCR), Riga Metropolitan Area (RMA)

Hematopoietic Stem/Progenitor Cells Express Functional Mitochondrial Energy-Dependent Cystic Fibrosis Transmembrane Conductance Regulator

Bone marrow-derived hematopoietic stem/progenitor cells (HSPCs) encompass a wide array of cell subsets with different capacities of engraftment and injured tissue-regenerating potential. The characterization/isolation of the stem cell subpopulations represents a major challenge to improve the efficacy of transplantation protocols used in regenerative medicine. Cystic fibrosis (CF) is one of the diseases whose hope of cure relies on the successful application of cell-based gene therapy. This study was aimed at characterizing murine HSPCs on the basis of their bioenergetic competence and CF transmembrane conductance regulator (CFTR) expression. Positively immunoselected Sca-1(+) HSPCs encompassed 2 populations distinguished by their different size, Sca-1 expression and mitochondrial content. The smaller were the cells, the higher was Sca-1 expression and the lower was the intracellular density of functional mitochondria. Reverse transcription-polymerase chain reaction and western blotting revealed that HSPCs expressed CFTR mRNA and protein, which was also functional, as assessed by spectrofluorimetric and patch-clamp techniques. Inhibition of mitochondrial oxidative phosphorylation by oligomycin resulted in a 70% decrease of both the intracelluar adenosine triphosphate content and CFTR-mediated channel activity. Finally, HSPCs with lower Sca-1 expression and higher mitochondrial content displayed higher CFTR levels. Our findings identify 2 subpopulations in HSPCs and unveil a so-far unappreciated relationship between bioenergetic metabolism and CFTR in HSPC biology

3D characterization of CdSe nanoparticles attached to carbon nanotubes

The crystallographic structure of CdSe nanoparticles attached to carbon nanotubes has been elucidated by means of high resolution transmission electron microscopy and high angle annular dark field scanning transmission electron microscopy tomography. CdSe rod-like nanoparticles, grown in solution together with carbon nanotubes, undergo a morphological transformation and become attached to the carbon surface. Electron tomography reveals that the nanoparticles are hexagonal-based with the (001) planes epitaxially matched to the outer graphene layer.Comment: 7 pages, 8 figure

Electron and ion spectroscopy of azobenzene in the valence and core shells

Azobenzene is a prototype and a building block of a class of molecules of extreme technological interest as molecular photo-switches. We present a joint experimental and theoretical study of its response to irradiation with light across the UV to x-ray spectrum. The study of valence and inner shell photo-ionization and excitation processes combined with measurement of valence photoelectron-photoion coincidence and mass spectra across the core thresholds provides a detailed insight into the site- and state-selected photo-induced processes. Photo-ionization and excitation measurements are interpreted via the multi-configurational restricted active space self-consistent field method corrected by second order perturbation theory. Using static modeling, we demonstrate that the carbon and nitrogen K edges of azobenzene are suitable candidates for exploring its photoinduced dynamics thanks to the transient signals appearing in background-free regions of the NEXAFS and XPS

Measurement of Gamma(phi -> eta' gamma)/Gamma(phi -> eta gamma) and the pseudoscalar mixing angle

We have measured the radiative decays phi -> eta gamma, phi ->etaprime gamma selecting pi+ pi- gamma gamma gamma final state in a sample of about 5 times 10^7 phi mesons produced at the Frascati phi factory DAFNE. We obtain Gamma(phi -> etaprime gamma)/Gamma(phi -> eta gamma)=(4.70 +- 0.47 +- 0.31) times 10^-3. From this result we derive new accurate values for the branching ratio BR(phi ->etaprime gamma) = (6.10 +- 0.61 +- 0.43) times 10^-5, and the mixing angle of pseudoscalar mesons in the flavour basis phi_P=(41.8 +1.9 -1.6) degrees.Comment: Submitted to Phys. Lett.