Identification of the hand-arm system mechanical impedance by simultaneous measurement of grip, transmitted force and acceleration with an adaptable instrumented handle

In this paper the results of static and dynamic tests carried out with an instrumented handle are presented and discussed. The instrumented handle was designed and constructed to be directly mounted on the handlebar of a two-wheeled vehicle and it can measure simultaneously grip, force transmitted by the handlebar to the hand and acceleration at the handle interface. The results of repeatability tests on the hand-arm weight and grip static measurement without and with real-time measure feedback show the importance of the use of an instrumented handle to ensure repeatability and also to estimate the influence of such parameters on the dynamic response. On the basis of preliminary dynamic tests conducted with the handle mounted on a shaker, the hand-arm system was characterized on two subjects, through a spectrum of its mechanical impedance as function of the excitation frequency, for different postures and grip levels. The results were compared to literature ideal impedance curves with acceptable agreement. The effect of grip showed to increase impedance in some specific frequency ranges

The ‘future’ of urban rent from the perspective of the metropolitan territorial plan of Naples

The Metropolitan City of Naples, as in the art. 1 of its Statute, aims «to restore the environment, to regenerate and reorder the urban tissue, to safeguard the common goods, guaranteeing their access, to reorganize the territorial polycentrism, overcrossing the center-periphery dichotomy and to promote the civil, social, cultural and economic development, enanching the diversities and the territorial excellences». In the Statute (at Article 35), the Metropolitan City is expected to provide coordination and general territorial planning by means of the Metropolitan Territorial Plan, consisting of a structural and an operational component, with measures of “urban equalization”. The structural component defines the vision of the territory, while the operational one programmes the actions of metropolitan interest to be implemented by the metropolitan city as well as the indications for the municipalities of the metropolitan city over a three-year period. In December 2017, the proposal for the Territorial coordination plan was adopted, which substantially recovers the Provincial Territorial Coordination Plan of 2007, repealing certain parts. The TCP of the metropolitan city of Naples is based on the redevelopment of the existing patrimony as a way of contrasting land consumption, in line with government plans. The main strategic elements of the plan, in fact, are the conservation and enhancement of the environmental, natural, cultural and landscape heritage, the adaptation of the housing supply, concentrating it only on the margins or within already established sites – densification –, and the enhancement and re-articulation of the urban system in a polycentric and reticular key. It is therefore, from this perspective, that this article seeks to elaborate a number of reflections on the possible ”future of urban rent” in the context of the metropolitan spaces of Naples, where the “potential” of the value of abandoned land in peripheral and/or peri- urban areas assumes a strategic role in the processes of regeneration and densification envisaged by the TCP. In terms of TCP operation, the principle should be to “expropriate” as little as possible, making use of the “equalization instrument” to ensure economic operators the necessary profit (an “interest in doing”)

Geometry optimization of a magnetorheological clutch operated by coils

Magnetorheological fluids are smart materials responsive to magnetic field, widely applied in dampers and shock absorbers but also in clutches and brakes. The magnetorheological fluid gap shape is a very important topic in the design of clutches, since it directly influences the transmissible torque and the power loss. In this paper, an approach to magnetorheological fluid clutch design based on optimization is proposed and tested on four different layouts. Starting from a given available volume, two magnetorheological fluid gap shapes, namely single cylinder and multi-disc, and two coils positions, i.e. internal or external, were considered. A lumped parameter model was developed to analytically compute the magnetic flux along the clutch magnetic circuit and to calculate the transmissible torque of the clutch. The optimal geometry of the clutch for maximum transmissible torque, in terms of number and dimensions of the coil sectors, was determined for each shape and coil configuration and the results were validated by finite element models

A novel test rig for the dynamic characterization of large size tilting pad journal bearings

The present work concerns the realization of a test bench for the dynamic characterization of high performance tilting pad journal bearings, within a collaboration between the Department of Civil and Industrial Engineering of Pisa, GE Oil&Gas and AM Testing. The objective is to cover journal diameters of interest of GE, from 150 to 300 mm, with peripheral speeds up to 150 m/s, static load up to 270 kN, dynamic loads up to 30 kN and frequencies up to 350 Hz, performances that make the apparatus very competitive worldwide. The adopted configuration has the test article (TA) floating at the mid-span of a rotor supported by two rolling bearings. The TA is statically loaded by a hydraulic actuator and excited dynamically by two orthogonal hydraulic actuators. Construction was recently concluded and preliminary tests are under way. In order to assess in advance the possible accuracy of the tests, a dynamic lumped parameter model of the test bench was developed to perform virtual experiments, including several possible sources of experimental errors and uncertainties. The model was implemented using reduced stiffness and mass matrices obtained from Finite Element Analysis by Component Modal Synthesis

Exploring life forms for linking Orthopteran assemblage and grassland plant community:

AbstractOrthopterans are well known to represent the majority of insect biomass in many grassland ecosystems. However, the verification of a relationship between the traditional descriptors of orthopteran assemblage structure and plant community patterns is not straightforward. We explore the usefulness of the concept of life forms to provide insights on such ecosystem level relationship. For this purpose, thirty sample sites in semi-natural calcareous grasslands were classified according to the relative proportion of dominant herbaceous plant life forms. Orthopteran species were grouped in four categories, based on the Bei-Bienko's life form categorization. The association among plant communities, orthopteran assemblages and environmental factors was tested by means of canonical correspondence analysis. Orthoptera groups were found to be associated with distinct plant communities, also indicating the effect of vegetation change on orthopteran assemblages. In particular, geobionta species were associated with all the most disturbed plant communities, while chortobionta and thamnobionta seemed to be dependent on better preserved grassland types. Therefore, the use of life forms could help informing on the relationships of orthopteran assemblages with grassland conservation state. Information on such community relationships at the local scale could also assist managers in the interpretation of habitat change maps in terms of biodiversity changes

Finite element parametric study of the influence of friction pad material and morphological characteristics on disc brake vibration phenomena

Since nowadays the NVH performance of vehicles has become an important priority, the noise radiating from brakes is considered a source of considerable passenger discomfort and dissatisfaction. Creep groan and squeal that show up with annoying vibrations and noise in specific frequency ranges are typical examples of self-excited brake vibrations caused by the stick-slip effect, the former, by the mode coupling of brake disc and friction pads or calliper, the latter. In both cases, the friction coefficient, which depends, among other factors, on the morphology of the mating surfaces and on the operating conditions, is a fundamental parameter but not the only one for the occurrence of the vibratory phenomena. Finite element complex eigenvalue parametric analyses were performed on a disc brake assembly to evaluate propensity to dynamic instability of brakes with multiple pads, as in railway brakes, as a function of the number of pads, pad shape and size, and material parameters

Using Genetic Algorithms for Real Estate Appraisal

The main aim of this paper is the interpretation of the existing relationship between real estate rental prices and geographical location of housing units in a central urban area of Naples (Santa Lucia and Riviera of Chiaia neighborhoods). Genetic algorithms (GA) are used for this purpose. Also, to verify the reliability of genetic algorithms for real estate appraisals and, at the same time, to show the forecasting potentialities of these techniques in the analysis of housing markets, a multiple regression analysis (MRA) was applied comparing results of GA and MRA

A Stochastic Model to Evaluate Pricing Distortions in Indemnity Insurance Methods for MTPL Insurance

Direct compensation or the direct reimbursement scheme is an indemnity insurance method that many European and American countries use to manage motor liability claims in which the driver that suffers an accident is paid by his/her insurance company that possibly later receives a flat-rate reimbursement (known as forfeit). Using non-life actuarial methodologies, this article analyses the distortion effects due to the direct compensation mechanisms and the effects of different forfeit reimbursement systems on policyholder tariffs in the management of motor liability claims involving vehicles in two different sectors, i.e. automobile and motorcycle. We empirically analyse and formalize the distortion effects resulting from the mechanism that different direct reimbursement systems produce, and explore the correlation between increasing tariffs for motorcycle policyholders and decreasing tariffs for other vehicle policyholders. We propose some alternative methods to overcome these distortion effects, evaluating their pricing impact through a stochastic model applied to a case study