h-multigrid agglomeration based solution strategies for discontinuous Galerkin discretizations of incompressible flow problems

In this work we exploit agglomeration based $h$-multigrid preconditioners to speed-up the iterative solution of discontinuous Galerkin discretizations of the Stokes and Navier-Stokes equations. As a distinctive feature $h$-coarsened mesh sequences are generated by recursive agglomeration of a fine grid, admitting arbitrarily unstructured grids of complex domains, and agglomeration based discontinuous Galerkin discretizations are employed to deal with agglomerated elements of coarse levels. Both the expense of building coarse grid operators and the performance of the resulting multigrid iteration are investigated. For the sake of efficiency coarse grid operators are inherited through element-by-element $L^2$ projections, avoiding the cost of numerical integration over agglomerated elements. Specific care is devoted to the projection of viscous terms discretized by means of the BR2 dG method. We demonstrate that enforcing the correct amount of stabilization on coarse grids levels is mandatory for achieving uniform convergence with respect to the number of levels. The numerical solution of steady and unsteady, linear and non-linear problems is considered tackling challenging 2D test cases and 3D real life computations on parallel architectures. Significant execution time gains are documented.Comment: 78 pages, 7 figure

IIoT Based Efficiency Optimization in Logistics Applications

The Industrial Internet of Thing (IIoT) approach to an Industry plant design, devises a comprehensive interconnection of the system components, from sections up to single devices, in order to get a general and punctual understanding of the process. Such an intelligent network, mostly based on Ethernet basic layers, when properly conceived, should be able to add relevant value to the plant operation. This paper shows how, within the IIoT frame topics, the plant efficiency can be addressed and bring relevant improvement. The reason is that variables directly related to the energy consumption, such as current, electric power, actuator and motor torque, speed, etc., can be timely and easily monitored in the entire plant, since they are already conveyed on the network, due to real time control and diagnostics purpose. A power consumption diagram can be derived, and give hints on how to optimize operations, based on some efficiency index. The paper, after a general discussion, proves it with practical examples based on a Gantry robot, driven in an EtherCAT based automation network, and on the stacker cranes of an automated warehouse

Un "visual" sugli IDN

Available in italianIl piano di comunicazione del Registro .it per il biennio 2011/2012 prevede la prosecuzione delle attivit? del precedente piano, con azioni che abbiano come obiettivo la promozione dell\u27immagine, della visibilit?, della conoscenza del Registro e la diffusione della cultura di internet. Rispetto al precedente piano, si ? cercato di introdurre strumenti nuovi, in grado di veicolare una comunicazione rapida e di impatto, che fosse per? sempre coerente con l\u27immagine coordinata e con il ruolo istituzionale del Registro. E\u27 nata quindi l\u27idea di realizzare un "visual" di grafica animata su un argomento prettamente tecnico: l\u27introduzione dei caratteri speciali nei nomi a dominio, conosciuti con l\u27acronimo Idn (internationalized domain name)

Un web cartoon per il Registro

Available in italianLe avventure del Prof. Itt?-I virus" ? un web cartoon interamente progettato e realizzato all\u27interno dell\u27unit? Relazioni Esterne, Media e Comunicazione del Registro. Il cartone animato, creato per il portale Innovascuola.gov.it, ? stato poi pubblicato sul sito web del Registro e proiettato nel corso di fiere ed eventi. Il target ? rappresentato da bambini in et? scolare (6-10 anni) e ha per argomento la sicurezza informatica, in particolare i virus. Nella presente pubblicazione sono descritti gli obiettivi del progetto, le principali fasi di lavoro, alcune specifiche tecniche e le prospettive future, tra le quali la realizzazione di altri episodi sul tema della navigazione sicura

A Comparison between High-order Temporal Integration Methods Applied to the Discontinuous Galerkin Discretized Euler Equations

Abstract In this work we present a high-order Discontinuous Galerkin (DG) space approximation coupled with two high-order temporal integration methods for the numerical solution of time-dependent compressible flows. The time integration methods analyzed are the explicit Strong-Stability-Preserving Runge-Kutta (SSPRK) and the Two Implicit Advanced Step-point (TIAS) schemes. Their accuracy and efficiency are evaluated by means of an inviscid test case for which an exact solution is available. The study is carried out for several time-steps using different polynomial order approximations and several levels of grid refinement. The effect of mesh irregularities on the accuracy is also investigated by considering randomly perturbed meshes. The analysis of the results has the twofold objective of (i) assessing the performances of the temporal schemes in the context of the high-order DG discretization and(ii) determining if high-order implicit schemes can displace widely used high-order explicit schemes

Pruritus: a useful sign for predicting the haemodynamic changes that occur following administration of vancomycin

INTRODUCTION: The aim of this study was to investigate the haemodynamic changes that follow the appearance of pruritus during vancomycin administration. METHODS: We studied 50 patients scheduled for coronary artery bypass surgery, and we compared data from patients who exhibited pruritus with those from patients who did not. After the monitoring devices had been positioned, vancomycin (15 mg/kg) was continuously infused at a constant rate over 30 min, before induction of anaesthesia. Haemodynamic profiles were recorded before vancomycin infusion (time point 1); at 15 (time point 2) and 30 min (time point 3) after the beginning of vancomycin infusion; and 15 min after vancomycin infusion had been stopped (time point 4). At each time arterial and mixed venous blood samples were drawn to calculate the shunt fraction (Qsp/Qt). RESULTS: In patients who exhibited pruritus (group A, n = 17) at time point 3 versus time point 1, systemic vascular resistance index (SVRI) and arterial oxygen tension (PaO(2)) decreased significantly; cardiac index (CI), stroke volume index (SVI) and Qsp/Qt increased significantly; and mean systemic pressure and heart rate were stable. Those changes were observed only in patients not treated with a β-blocker before surgery, whereas no change occurred in patients treated with the drug. In the patients who were free from pruritus (group B, n = 28), we did not observe any significant change. CONCLUSION: The appearance of pruritus during vancomycin administration indicates that SVRI is declining, thus exposing the patient to risk for hypotension. Therapy with a β-blocker appears to confer protection against this hemodynamic reaction

Non-Intubated Thoracic Surgery: Standpoints and Perspectives

Non-intubated video-assisted thoracic surgery (NI-VATS) combines the advantages of a non-intubated surgery with the benefits of a minimally invasive approach. First, NI-VATS is performed in the case of fragile patients when general anesthesia and/or orotracheal intubation can be foreseen as inconvenient. However, NI-VATS indications have been increasingly extended to different patient conditions, considering the increasingly assessed safety and feasibility of the procedure. Currently, the NI-VATS approach is used worldwide for different thoracic surgery procedures, including the management of malignant pleural effusion, surgical treatment of empyema, anatomical and non-anatomical lung resection, and other indications. In fact, this approach has shown to be less impactful than VATS under general anesthesia, allowing for shortened hospitalization and faster recovery after surgery. Besides, NI-VATS is associated with fewer pulmonary complications, less respiratory distress, and a mild systemic inflammatory reaction. For these reasons, this approach should be considered not only in patients with poor cardiac or respiratory function (general functional reserve), but also in other eligible conditions. We explored the anesthetic and surgical aspects of such an approach, including the management of analgesia, cough reflex, depth of sedation, and intraoperative technical issues to put this approach in perspective