112 research outputs found
Turbulent stresses at the bottom surface near an abutment: a laboratory-scale numerical experiment
No full textA Markov state modeling analysis of sliding dynamics of a 2D model
No full textNon-equilibrium Markov State Modeling (MSM) has recently been proposed by Pellegrini et al. [Phys. Rev. E 94, 053001 (2016)] as a possible route to construct a physical theory of sliding friction from a long steady state atomistic simulation: the approach builds a small set of collective variables, which obey a transition-matrix-based equation of motion, faithfully describing the slow motions of the system. A crucial question is whether this approach can be extended from the original 1D small size demo to larger and more realistic size systems, without an inordinate increase of the number and complexity of the collective variables. Here we present a direct application of the MSM scheme to the sliding of an island made of over 1000 harmonically bound particles over a 2D periodic potential. Based on a totally unprejudiced phase space metric and without requiring any special doctoring, we find that here too the scheme allows extracting a very small number of slow variables, necessary and sufficient to describe the dynamics of island sliding
Analisi delle decisioni della Commissione centrale per gli esercenti le professioni sanitarie relative ai farmacisti
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DEDALO: Device for Enhanced Dust Analyses with Light Obscuration sensors
No full textInstruments based on light obscuration sensors are widely used for measuring the size distribution of insoluble sub-visible particles in liquid suspensions, being fast and suitable for in situ and real-time measurements. Such instruments are typically calibrated by means of reference polystyrene spherical particles with a specific refractive index, which unavoidably leads to systematic errors when determining the size of particles of different materials. In this paper, we propose a reliable and consistent method to overcome this limitation by setting the refractive index value according to the sample, thus achieving an improved particle size distribution (PSD) measurement. An ad hoc, ready-to-use, open source code with a graphical interface able to drive an in-line instrument and obtain a real-time correction to the PSD has been developed. The method has been extensively validated with several oil emulsions characterized by different refractive index values and the results have been compared with an independent optical method. As an example of application, we have adopted this approach for the analysis of dust suspended in meltwater of an ice core from a glacier in the Aosta Valley (Italy). We believe that our approach will strongly improve the accuracy in characterizing liquid suspensions and reduce discrepancies between data obtained with different methods. The code has been made publicly available at: https://instrumentaloptics.fisica.unimi.it/dedalo/ and on the GitHub page of the corresponding author (https://github.com/LucaTeruzzi/DEDALO)
Feasibility and Diagnostic Accuracy of Quantitative Assessment of Mechanical Prostheses Leaflet Motion by Transthoracic and Transesophageal Echocardiography in Suspected Prosthetic Valve Dysfunction
No full textTransthoracic (TTE) and transesophageal echocardiography (TEE) are the standard techniques for the evaluation of prosthetic valve function. However, quantitative evaluation of leaflet(s) motion is not routinally carried out, although leaflet(s) opening and closing angle measurements are important information to recognize prosthetic dysfunction. For this purpose, cinefluoroscopy is considered the "gold standard" technique. The aim of this study was the evaluate the diagnostic accuracy of TTE and TEE in the quantitative assessment of leaflet motion in patients with mechanical protheses. One hundred-eleven patients with mitral (single disk 18; bileaflet 48) and aortic (single disk 22; bileaflet 23) prostheses, were referred to TTE, TEE, and cinefluoroscopy for electrical cardioversion of atrial fibrillation (n = 40) or suspected prosthesis dysfunction (n = 71). Echocardiographic evaluation included leaflet(s) opening and closing angle measurements; results were compared with cinefluoroscopy. For mitral prostheses, opening and closing angles were correctly identified by TTE in 85% and by TEE in 100% of patients, regardless of prosthetic valve type, with a good concordance with cinefluoroscopy. For aortic prostheses, opening angles were correctly identified by TTE and TEE, respectively, in 40% and 77% of patients with single-disk and in 13% and 35% of patients with bileaflet prostheses. Both TTE and TEE were rarely able to identify closing angles. In conclusion, quantitative evaluation of mitral leaflet(s) motion may be accurately achieved with TTE and TEE, leading to increased diagnostic efficacy of prosthetic valve dysfunction. In the aortic position, TTE and TEE allow a quantitative evaluation of leaflet(s) dynamics only in a minority of patients and cinefluoroscopy still remains the first-choice technique
A Comparison of Response Criteria in Patients with Juvenile Idiopathic Arthritis Treated with Methotrexate And/or Anti-Tnfα Agents
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