325 research outputs found
"Bal" di Vladimir F. Odoevskij: ballo o danza macabra?
No full textNel 1833 Vladimir F. odoevskij pubblicò un brevissimo racconto, Bal, appena tre pagine, dove si descrive un ballo per festeggiare una vittoria sanguinosissima (dei russi contro Napoleone?), e dà occasione per un ballo sfrenato. Il saggio analizza la festa che si svolge in un palazzo sontuoso, ma il ballo lentamente, secondo l’analisi e interpretazione da noi proposta, assume tutte le caratteristiche e il significato di una danza macabra, dove la morte è costantemente presente, decidendo il destino dell’uomo
Trifilar pendulum: Non-small oscillations and calibration
No full text• Motivation • Trifilar pendulum linear model • Trifilar pendulum non-linear model • Period estimation in large oscillations • Numerical validation • Moment of inertia measurement with large oscillations • Experimental tests
Early improvement in cardiac function detected by tissue Doppler and strain imaging after melphalan-dexamethasone therapy in a 51-year old subject with severe cardiac amyloidosis.
No full textAbstract
We report the case of a 51-year old man with symptoms of heart failure due to severe cardiac amyloidosis, in whom treatment with melphalan and dexamethasone yielded significant improvement in clinical status and both systolic and diastolic left ventricular (LV) function over a 12-week follow-up. The improvement in LV performance was detected by Tissue Doppler (TD) and strain analysis, despite no changes in standard indices such as ejection fraction and Doppler pattern of mitral inflow. Color TD-derived myocardial velocity and deformation indices also revealed a reduction in intra-ventricular early diastolic asynchrony after therapy. In addition, an improvement in intra-ventricular systolic synchrony was detected by strain rate and strain, but not by color TD velocity imaging. These findings suggest that treatment with melphalan and dexamethasone may improve symptoms of heart failure and LV performance in subjects with cardiac amyloidosis, and that TD and particularly strain imaging could represent useful techniques to monitor the effect of therapy on LV function in the follow-up of these patients
Optimal design of a beam subject to bending: a basic application
No full textThe minimisation of both the mass and deflection of a beam in bending is addressed in the paper. To solve the minimisation problem, a multi-objective approach is adopted by imposing the Fritz John conditions for Pareto-optimality. Constraints on the maximum stress and elastic stability (buckling) of the structure are taken into account. Additional constraints are set on the beam cross section dimensions. Three different cross sections of the beam are analysed and compared, namely the hollow square, the I-shaped and the hollow rectangular cross sections. The analytical expressions of the Pareto-optimal sets are derived. As expected, the I-shaped beam exhibits the best compromise in structural performance, which is related on the particular loading considered
Experimental methods to measure the lateral characteristics of bicycle tyres–a review
No full textTyre characteristics can strongly affect bicycle dynamics. In light of this, proper test-rigs are required to accurately measure tyre parameters. The paper presents a review of the methods and devices developed for the experimental characterisation of bicycle tyres in the lateral direction. The main aspects of the known test devices are described, highlighting the respective features. The technology of test-rigs for bicycle tyre parameter measurement seems to be just beginning
Concurrent topological optimization of two bodies sharing design space: problem formulation and numerical solution
No full textTopology optimization is a widely used technique for deriving efficient structural layouts for components in many engineering fields. The optimization process deals with the definition of the optimal material distribution of single components subjected to specified loads and boundary conditions, in case made of different materials or with embedded regions corresponding to other components or actuators. In this paper, a novel topology optimization problem is proposed. The case of the concurrent topological optimization of two different components sharing a part of the design spaces is considered. The design problem represents a design situation in which more than one component has to be fitted in an enclosed space and each component has its own load carrying function. In the paper, the problem is solved by a numerical technique able to allocate the common part of the design space to each component. Inside the allocated space, the actual material distribution of the component is optimized by a standard topological optimization algorithm. Numerical examples are provided to show the potentialities of the method. A (simplified) practical design problem is also considered
MASS MANAGEMENT OF A HIGH ENERGY-EFFICIENT BATTERY ELECTRIC VEHICLE
No full textThe paper presents a detailed analysis of the mass-induced power demand of an ultra-efficient battery electric vehicle. The vehicle belongs to a special class of lightweight quadricycles, designed for participating to efficiency competitions. The influence of reducing the mass of the entire vehicle and the mass of the wheels on the vehicle energy consumption is assessed. A sensitivity analysis is performed by exploiting a “tank-to-wheel” multi-physics model of the vehicle. The model includes the main vehicle subsystems and the principal sources of power dissipation are modelled. A three-step sensitivity analysis is carried out: firstly, the influence of the mass reduction on the energy saving is analysed for two different race tracks; then, two different driving behaviour on the same track are compared; finally, the potential energy saving due to actual lightweighting interventions performed on the vehicle is computed. In this phase, secondary mass reduction effects (battery downsizing) are included in the simulation. Results are expressed in terms of Energy Reduction Value (ERV), a parameter widely used in the literature to quantify the correlation between mass reduction and energy saving. The vehicle studied in this paper shows an ERV due to vehicle mass reduction ranging from 0.23 to 0.36 kWh/(100 km∙100 kg), while wheel lightweighting leads to an ERV ranging from 1.03 to 1.74 kWh/(100 km∙100 kg)
A study on the stress gradient reconstruction in finite elements problems with application of radial basis function networks
No full textThe recovery of the stress gradient in finite elements problems is a widely discussed topic with many applications in the design process. The stress gradient is related to the second derivative (Hessian) of the nodal displacements and numerical techniques are required for its calculation. Particular difficulties are encountered in the reconstruction of the stress gradient in the boundary regions of the domain. This is of particular concern in most applications, especially in mechanical components, where the maximum values of stresses are often located in these regions and the stress gradient has a strong influence on the fatigue life of the component. This paper presents a comparison between some already published, partially modified, recovery techniques and a different approach based on radial basis function networks. The aim of the paper is to compare the performances of the different approaches for a number of element types with particular focus on the boundary regions. Some examples of mechanical interest are considered
A Portable device for measuring the cog: Design, error analysis and calibration
No full textThe paper is devoted to the design, error estimation and calibration of a portable device for the measurement of the centre of gravity of rigid bodies. The device consists in a simple but effective implementation of the knife edge method. The design of the device including safety considerations is fully described. An error estimation approach is employed in the very early stage of the design to assess the required instrumentation accuracy and the manufacturing tolerances. A calibration of the portable device is performed by means of proper calibrated masses. After calibration, the accuracy of the device corresponds to the target accuracy defined in the a-priori error analysis. The design procedure described in the paper shows a straightforward approach for the design of devices for the measurement of the inertia properties. By such a procedure, it is possible to identify the most critical design areas and make the correct choices in the early stage of the design process. Also, a deep understanding of the measuring process can be gained allowing the definition of an effective calibration procedure
Portamozzo sensorizzato
No full textLa presente invenzione si riferisce a un portamozzo (101) comprendente: un alloggiamento centrale (103) per un mozzo (100) per una ruota di veicolo; un telaio esterno (104) atto a connettere il portamozzo (101) a una sospensione del veicolo; almeno tre razze (107) interposte tra l’alloggiamento centrale (103) e il telaio esterno (104), le almeno tre razze (107) essendo rigidamente connesse all’alloggiamento centrale (103), le almeno tre razze (107) comprendendo rispettivi elementi terminali (109) connessi al telaio esterno (104) e realizzanti rispettive cerniere sferiche traslanti per le almeno tre razze (107); il portamozzo (101) comprendendo ulteriormente almeno tre sensori (201) configurati per rilevare componenti di forze e/o momenti agenti sul mozzo (100)
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