1,448 research outputs found
A procedure for the definition of a patient-specific kinematic model of the knee joint: an in-vivo validation
No full textThe capability to model human joint motion is a fundamental step towards the definition of effective treatments and medical devices, with an increasing request to adapt the devised models to the specificity of each subject. We present an approach for the definition of subject-specific models of the knee natural motion. The approach is the result of a combination of two different techniques and exploits the advantages of both. It relays upon non invasive measurements that can be performed in vivo, based on which a kinematic model of the natural motion is built, suitable to be extended to the definition of static and dynamic models. Comparison of the model outcomes with in-vivo measurements performed on one subject shows promising results supporting the proposed approach
Modelling Annihilation Properties of Positronium Confined in Nanoporous Materials: A Review
No full textPositronium (Ps) is a valuable probe to investigate nanometric or sub-nanometric cavities in non-metallic materials, where Ps can be confined. Accessible experimental measurements concern the lifetime of trapped Ps, which is largely influenced by pick-off processes, depending on the size of the cavity as well as on the density of the electrons belonging to the surface of the host trap. Another relevant physical quantity is the contact density, that is the electron density at the positron position, which is usually found to be well below the vacuum value. Here, we review the principal models that have been formulated to account and explain for these physical properties of confined Ps. Starting with models, treating Ps as a single particle formulated essentially to study pick-off, we go on to describe more refined two-particle models because a two-body model is the simplest approach able to describe any change in the contact density, observed in many materials. Finally, we consider a theory of Ps annihilation in nanometric voids in which the exchange correlations between the electron of Ps and the outer electrons play a fundamental role. This theory is not usually taken into account in the literature, but it has to be considered for a correct theory of pick-off annihilation processes
Static and dynamic testing of the “Filomena Delli Castelli” bridge
No full textThe paper describes the static and dynamic testing of the “Filomena Delli Castelli”cable-stayed bridge over the Saline River, in the Pescara province (Italy), having main span of 103.4 m and total length of 188.6 m
A ligament model based on fibre mapping for multibody simulations
No full textA ligament model is proposed to define the wrench of a ligament on
the bones during multibody simulations. The model is based on the thin-plate
spline mapping to adapt reference data on the anatomy of a specific subject and to
define a correspondence between the points on the two insertions of the ligament
on the bones, thus simulating the ligament fibrous structure. Tests performed on a
ligament show that the model is faster, more accurate and easier to be implemented
than a standard multi-bundle model. The accuracy can be also easily
adjusted to the application in order to further reduce computational time
Positronium Confined in Nanocavities: The Role of Electron Exchange Correlations
No full textPositronium atoms (Ps) are commonly employed as a probe to characterize nanometric or subnanometric voids or vacancies in nonmetallic materials, where Ps can end up confined. The annihilation lifetime of a trapped Ps is strongly modified by pickoff and depends on the cavity size and on the electron density in the confining cavity surface. Here, we develop a theory of the Ps annihilation in nanocavities based on the fundamental role of the exchange correlations between the Ps-electron and the outer electrons, which are not usually considered but must be considered to correctly theorize the pickoff annihilation processes. We obtain an important relation connecting the two relevant annihilation rates (for the p-Ps and the o-Ps) with the electron density, which has the property of being totally independent of the geometrical characteristics of the nanoporous medium. This general relation can be used to gather information on the electron density and on the average cavity radius of the confining medium, starting from the experimental data on PALS annihilation spectra. Moreover, by analyzing our results, we also highlight that a reliable interpretation of the PALS spectra can only be obtained if the rule of 1/3 between the intensities of p-Ps and o-Ps lifetimes can be fulfilled
Strategie di personificazione nel proemio De Antiquis Oratoribus di Dionigi D’Alicarnasso
No full textThe study performs a rhetorical and lexical analysis of Dion. Hal. de orat. 1.1-7 Aujac; it is also
aimed at contextualizing its argumentative and formal emphasis in the poorly documented
oratorical production of the early Imperial in which a new stylistic taste arises
L’appropriation et les modifications du SignWriting (SW) par des locuteurs de la Langue des Signes Italienne (LIS)
No full textPreliminary multi-omics analysis of BDNF effects in an ischemic stroke model of cerebral organoids
No full textAnnual Meeting 2025 of the PhD Course in Cellular and Molecular Biotechnologie
Stiffness analysis of spatial strip-driven devices
No full textOrthoses and exoskeletons require simple yet accurate devices to assist human joints in their motion. This paper presents the stiffness analysis of a spatial-strip driven device suitable for this application. The device features two cylinders guided by three flexible strips, so that a pure rolling relative motion between the two cylinders is generated. The analysis is conducted by defining analytical models to predict the equilibrium position of the device under different loading conditions. Only axial stiffness of the flexible strips is considered, while the effects of flexural and torsional stiffness are ignored as well as friction
Large-signal device simulation in time- and frequency-domain: a comparison
No full textThe aim of this paper is to compare the most common time- and frequency-domain numerical techniques for the determination of the steady-state solution in the physics-based simulation of a semiconductor device driven by a time-periodic generator. The shooting and harmonic balance (HB) techniques are applied to the solution of the discretized drift-diffusion device model coupled to the external circuit embedding the semiconductor device, thus providing a fully nonlinear mixed mode simulation. The comparison highlights the strong and weak points of the two approaches, basically showing that the time-domain solution is more robust with respect to the initial condition, while the HB solution provides a more rapid convergence once the initial datum is close enough to the solution itsel
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