The paper investigates the influence of vehicle mass properties (mass, centre of gravity location, inertia tensor) on accident reconstruction. Considering the case of two colliding vehicles, the paper aims at defining which is the uncertainty of each mass property that should be prescribed to obtain an accurate accident reconstruction. The paper is divided into two parts. The first part presents a mathematical model, and its validation, able to perform a proper computation of the motion of vehicles before and after crash with the data that are usually collected by operators after the accident. In the second part, a theoretical analysis shows that an accurate accident reconstruction does need accurate measurements of both the centre of gravity location and the moment of inertia of crashed automobiles. Even a small error of 10% on the estimated value of the moment of inertia of one car or of an error of 100 mm in the location of its centre of gravity can lead to errors of close to 20% on the reconstructed velocities of the two cars before the accident. An existing test rig for measuring the centre of gravity location and the inertia tensor of crashed vehicles (pre-and post-impact), meeting the measurement accuracy determined on the basis of the sensitivity analysis, is presented.

Based on an array of combined metal oxide and conductive polymer gas sensors electronic an odor recognition system is being developed for detection of bacteria types at the early stages of wound infection. It is proved by GC-MS studies that living bacteria that are typical infectious agents in clinical practice can be distinguished from each other by means of a limited set of key volatile products. Using a set of these reference volatile compounds criteria for selection and calibration of gas sensors were defined. Aiming to increase reliability of bacteria identification SPME preconcentration was used for sampling of the headspace air and response to variable concentrations of volatiles emitted from the SPME fiber is processed for evaluation of the output parameters of the sensor module. Discrimination between classes of volatile products is obtained by a PCA analysis of the dynamic parameters of sensor responses to the headspace air of clinical samples collected by swabbing.I.

The paper deals with the mathematical reconstruction of road accidents. Often, many of the relevant parameters for an accurate simulation are not known. The aim of the paper is to introduce and validate a new method to identify these (many) relevant parameters, such as exact impact location, tyre-road friction, ... The velocity of the two vehicles before the impact are computed by applying the principle of conservation of momentum and angular momentum and by estimating the kinetic energy losses. The identification process is based on a Global Approximation technique. Up to 17 numerical values pertaining to both running conditions before impact and parameters can be defined accurately and in a relatively short time. The definition of the 17 numerical values is made on the basis of the known data coming from the positions of the vehicles at rest and from tyre marks (if present and measured). The method has undergone a preliminary validation. Two case studies are presented which show the effectiveness of the identification method.

In the present paper, the press fitting of railway wheels is studied with the aim of defining the mechanical and physical parameters to be adopted in order to reduce as much as possible the damaging of both wheel and axle during repeated press fitting and wheel removals. The study has been performed in a theoretical way, through a new multi objective optimisation method based on finite elements analyses. The FEM model has been experimentally validated. Referring to an actual case, the parameters that influences the press fitting process have been determined. The parameters influence was related not only to the mechanical stresses into the structures of wheel and axle respectively, but also to the robustness of the design (sensitivity to the machining tolerances and to friction coefficient variation at the press fit surfaces). Some optimal solutions have been determined and compared (in terms of performances) with an actual production one.

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