625 research outputs found
An analysis of the action of dowels on the stabilisation of rock blocks on underground excavation walls
No full text
The complexity of platlet metabolism and its contribution to atherotrombosis
No full textActa Cardiol. 2009 Apr;64(2):157-65.
The complexity of platelet metabolism and its contribution to atherothrombosis.
Puddu P, Muscari A, Puddu GM, Cravero E, Giannoni C, Zoli M.
Department of Internal Medicine, Ageing and Nephrological Diseases, University of Bologna and S. Orsola-Malpighi Hospital, Bologna, Italy.
Platelet functions are multiple, complex and not limited to haemostasis. In fact, platelets play a relevant role in vascular inflammation and atherosclerosis (ATS). In the presence of vascular lesions or inflammation, endothelial denudation or activation triggers mechanisms that render the circulating platelets adhesive for the vascular wall. Endothelial lesions expose subendothelial matrix components, such as collagen, von Willebrand factor, fibronectin and other adhesive proteins. Platelet adhesion depends on the interaction between these components and platelet receptors (mainly glycoprotein (GP) VI and GPlb-IX-V). Adhesion triggers the platelet release of inflammatory and mitogenic substances that alter the thromboresistant endothelial surface, enhance the chemoattraction of leukocytes, stimulate smooth muscle cell proliferation and contribute to matrix degradation. Finally, GPIIb-IIIa receptors are activated, leading to firm platelet aggregation and thrombus formation. Platelets participate in the formation of mural thrombi in the late stages of atherosclerotic disease, but also adhere to endothelial cells during the earlier stages of atherosclerotic plaque development. Moreover, platelets exert important functions in modulating inflammatory and immune processes. An improved comprehension of the complex platelet pathophysiology could suggest new therapeutic strategies to reduce the impact of atherosclerotic disease.
PMID: 19476106 [PubMed - indexed for MEDLINE
On the accuracy of WENO and CWENO reconstructions of Third Order on NonUniform Meshes
No full textThird order WENO and CWENO reconstruction are widespread high order reconstruction techniques for numerical schemes for hyperbolic conservation and balance laws. In their definition, there appears a small positive parameter, usually called , that was originally introduced in order to avoid a division by zero on constant states, but whose value was later shown to affect the convergence properties of the schemes. Recently, two detailed studies of the role of this parameter, in the case of uniform meshes, were published. In this paper we extend their results to the case of finite volume schemes on non-uniform meshes, which is very important for h-adaptive schemes, showing the benefits of choosing as a function of the local mesh size . In particular we show that choosing or is beneficial for the error and convergence order, studying on several non-uniform grids the effect of this choice on the reconstruction error, on fully discrete schemes for the linear transport equation, on the stability of the numerical schemes. Finally we compare the different choices for in the case of a well-balanced scheme for the Saint-Venant system for shallow water flows and in the case of an h-adaptive scheme for nonlinear systems of conservation laws and show numerical tests for a two-dimensional generalisation of the CWENO reconstruction on locally adapted meshes
A design methodology for radial turbomachinery. Application to turbines and compressors
No full textSviluppo di una procedura per il progetto e la verifica di turbomacchine radialiDifferent design/analysis tools are combined in an automatic procedure for the design of radial turbomachinery. The algorithms developed have different complexity levels ranging from the meanline one-dimensional design tool to the fully three-dimensional Navier-Stokes based analysis. Each code gives complementary information to the designer. The codes have been written and developed by the author at DIMSET. The design procedure is developed for both radial compressors and turbines and it is proposed for the dimensioning of rotating machinery for microgasturbine power plants
Modelli previsionali del flusso negli ammassi rocciosi fratturati
No full textIl lavoro intende presentare importanti aspetti della modellistica geoidrologica negli ammassi rocciosi fratturati. Riconoscendo la stretta dipendenza delle caratteristiche e della variabilità del flusso di fluidi dalla struttura geometrica dei sistemi di fratture naturali, si considerano sia i principali elementi di caratterizzazione e di modellazione geometrica dello stato di fratturazione, sia le tecniche numeriche per l'approssimazione del problema di flusso in domini a conduttività discreta. La modellazione geometrica e la successiva modellazione del flusso sono, in ogni caso, essenziali e non separabili per la soluzione coerente del problema geoidrologico. Si presentano, corredandoli con esempi ideali d'uso, differenti alternative di modello geoidrologico: il modello a fratture discrete DFN, il modello a pipette equivalenti, il modello stocastico continuo SCM, la caratterizzazione idrologica mediante il mezzo poroso equivalente EPM
Analysis of the Operating Mode Influence onto Energy Consumption of a Natural Gas Storage Plant ASME Paper GT2012-68990
No full textSimulazione impianto di compressione e stoccaggio gas con analisi del processo tramite algoritmo di ottimizzazion
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