University of Palermo

About: University of Palermo is a education organization based out in Palermo, Italy. It is known for research contribution in the topics: Population & Cancer. The organization has 15621 authors who have published 40250 publications receiving 964384 citations. The organization is also known as: Università degli Studi di Palermo & Universita degli Studi di Palermo.

A critical analysis on the friction modelling in orthogonal machining

Abstract: Despite the development of high performance finite element-based codes, the simulation of machining still represents a very hard task due to the geometric complexity of the real chip-tool systems and the high cutting speed that requires very long simulation times. For these reasons, many aspects related to machining are not very clear and so easy to simulate. In this paper a rigorous investigation on the role played by the implemented friction model within a 2D simulation of orthogonal cutting was carried out, taking into account different models proposed by the researchers in the last years. The main simulation results were compared with experimental measurements in order to verify if it is possible to identify the best model. Once the comparison with mechanical variables was completed, a subsequent study on temperature predictions utilizing the above friction models was executed as well. The results of this integrated numerical and experimental work are carefully reported in the paper.

Comparative investigation of the freezing phenomena for quantum correlations under nondissipative decoherence

Abstract: We show that the phenomenon of frozen discord, exhibited by specific classes of two-qubit states under local nondissipative decoherent evolutions, is a common feature of all known bona fide measures of general quantum correlations. All those measures, despite inducing typically inequivalent orderings on the set of nonclassically correlated states, return a constant value in the considered settings. Every communication protocol that relies on quantum correlations as a resource will run with a performance completely unaffected by noise in the specified dynamical conditions. We provide a geometric interpretation of this phenomenon.

Malnutrition in elderly: Social and economic determinants

Abstract: Malnutrition occurs frequently in the frailest groups of the population, especially in people who are on a low income and elderly subjects, overall if they are institutionalized. The aim of this study was to assess the prevalence of malnutrition in a sample of elderly people living in different settings and to identify the determinants of malnutrition. Methods:A total of 718 subjects, 472 females (F) and 246 males (M), were recruited from nursing homes or were free living in three different regions in Italy. Nutritional status, depression, social, functional and cognitive status, were evaluated. Results:According to the Mini Nutritional Assessment (MNA), a high prevalence of malnutrition was found out in both genders: 26% of F and 16.3% of M were classified as being malnourished (MNA<17); 40.9% of F and 35% of M were at risk of malnutrition (MNA 17- 23,5). The prevalence of malnutrition was significantly higher in NH subjects in both sexes. Moreover, a relationship was shown between malnutrition and inability to shop, prepare and cook meals because of a low income, distance from markets or supermarkets as well as impossibility to drive the car or to use public transportation. This study confirms the necessity to routinely perform nutritional status evaluation in elderly subjects, to carry out training courses for health workers (doctors, nurses, psychologists, dietitians), to implement nutritional education of the geriatric population, to develop tools and guidelines for health workers and caregivers, to identify and reduce clinical, functional, social or economic risk factors for malnutrition.

A comparison of different one-diode models for the representation of I–V characteristic of a PV cell

Abstract: Predictive performance tools are an important factor in the success of any new technology because they permit demonstration of whether a system will be efficient and economically feasible. A reliable predictive tool should allow the designer to optimise system performance and to maximise the cost effectiveness of a system prior to installation. This article discusses the five main parametric models for photovoltaic (PV) systems available in the literature. The current–voltage characteristics of a photovoltaic module can be reproduced modelling the PV panel as an equivalent electrical circuit made of linear and non-linear components. The parameters describing such components are directly related to the performance characteristics of the specific PV panel, which are generally available in a graphic form with respect to standard values of temperature and incident irradiance. Five of the most recent models are analysed in detail describing the algorithm, showing how the parameters were determined and highlighting the most important mathematical and physical assumptions that characterised each model and the calculation process. To simplify the examination and reading of the procedures referred to in the five models, all equations are rewritten using the same nomenclature. Furthermore, to assess the accuracy of each model with respect to the data provided by the manufacturer, this paper compares the I–V and P–V curves at various temperatures and irradiance for a generic PV panel.