516 research outputs found
Modeling and experimental characterization of belt drive systems in micro-hybrid vehicles
Belt Drive Systems (BDS) constitute the traditional automotive mechanism used to power the main internal accessories (such as the alternator, water pump and air conditioning pump) taking power from the engine's crankshaft rotational motion. BDS usually work in the severe ambient conditions of the engine compartment and are subject to highly dynamic excitations coming from the crankshaft harmonics. The substitution of the traditional alternator with an electric machine, namely Belt Starter Generator (BSG), is the most promising micro-hybrid technology towards a quick and effective satisfaction of the current regulations of fuel consumption and pollutant emissions reduction. The use of a BSG leads to increased stresses in the already complex front end accessory drive. As a matter of fact, a BSG is an electrical machine able to work both as motor and as generator and defines two distinct functioning modes of the drive, namely motor and alternator modes. The relative alternation of tight and slack spans profoundly changes the functionality of the overall drive and affects its transmissions capability and efficiency, furthermore resulting in NVH (noise vibration harshness) effects that need to be carefully addressed. Traditional automatic tensioners acting on the slack span of the alternator mode application are not capable of facing the irregular stresses of a BSG-based BDS which requires the use of a tensioning device capable of keeping the belt tension inside a safe range and of preventing slippage during all the operating conditions of the drive. With this goal many solutions are currently being investigated, such as the cooperation of two tensioners one for each span, active tensioners, double arm tensioners or hydraulic tensioners. The critical issues due to the involvement of BSG in BDS require a deep study focused on the tension conditions of the belt and its influence on the overall efficiency of the system.
The aim of the research described in this thesis is to obtain a defined modelling approach of belt drive systems for micro-hybrid vehicles and to validate it through extensive experimental analysis.
To obtain a reliable testing environment, a dedicated full-electric test rig was designed and realized. The test rig presented in this work is capable of assuring the repeatability and accuracy of the measurements leaving aside the uncertainties deriving from the irregularities of the ICE behaviour that usually affect the experimental activities conducted on front engine accessory drives.
After providing both the modelling and testing environment as assets for the analysis, several experimental activities are carried out with the goal of assessing the dynamic behaviour of belt drive systems and their efficiency, comparing the performances of different tensioning solutions, understanding the behaviour in static and dynamic conditions of a traditional automatic tensioner and one example of an omega twin arm tensioner, which is the tensioning solution most explored by the manufacturers at present.
The ultimate goal of gaining a complete understanding of belt drive systems in the special case of micro-hybrid vehicles is eventually fulfilled by an experimental validation of the static and dynamic models proposed
Bioactive Compounds in Goat Milk and Cheese: The Role of Feeding System and Breed
This chapter provides an introductory overview of some bioactive compounds in goat milk, presenting a selection of key results from literature. The aim of the chapter is to review the effects of the feeding system and of the breed on goat milk and cheese fine quality in order to identify management options aimed at improving the nutraceutical characteristics of milk and dairy products. We will discuss a series of case studies focused on the assessment of the effects of feeding system and breed and their interaction on specific health-promoting bioactive compounds: (i) fatty acid (FA) profile, (ii) antioxidant compounds and (iii) oligosaccharides (OS). Experimental data will be discussed highlighting the potential role of local Mediterranean breeds for the production of functional dairy products
Two-dimensional superconductivity driven by interfacial electron-phonon coupling in a BaPbO3/BaBiO3 bilayer
The recent discovery of two-dimensional (2D) superconductivity at the interface of BaPbO3 (BPO) and BaBiO3 (BBO) has motivated us to study in depth the electronic and structural properties and the relation between them in this particular heterostructure, by means of first-principles calculations. Our results indicate that the breathing distortions, the charge ordering, and the semiconducting behavior that characterize the parent compound BBO in its bulk form are preserved at the innermost layers of the BBO side of the BPO/BBO bilayer. On the other hand, at the interface, there is a partial breaking of the breathing distortions with a concomitant charge transfer between the interfacial Bi ions and the on top BPO layer. We show that two types of carriers coexist at the interface, the delocalized three-dimensional-like sp states coming from Pb ions and the quasi-2D s states from the Bi ones. We obtain a substantial electron-phonon coupling between the 2D Bi states with the interfacial stretching phonon mode and a large density of states that can explain the critical temperature experimentally observed below 3.5 K. We hope these findings will motivate future research to explore different interfaces with charge-ordered semiconductors such as BBO in order to trigger this fascinating 2D behavior.Fil: Di Napoli, Solange Mariel. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Constituyentes | Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Constituyentes.; ArgentinaFil: Helman, Christian. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Constituyentes | Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Constituyentes.; ArgentinaFil: Llois, Ana Maria. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Constituyentes | Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Constituyentes.; ArgentinaFil: Vildosola, Veronica Laura. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Constituyentes | Comision Nacional de Energia Atomica. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia. Unidad Ejecutora Instituto de Nanociencia y Nanotecnologia - Nodo Constituyentes.; Argentin
The model of schools for health in Europe: startup of the IGEA network for the city of Palermo
The contribution analyses the process of creating of the IGEA network (Integrated Generativity Actors) inscribed in the framework of the Schools for Health in Europe (SHE network). This model moves from a focus on school context only (as single setting) to the integration of schools and their surrounding community services, sports clubs, hospitals, workplace, informal contexts (building integrated multi-setting approach) (SHE, 2019; Novara & Guidi, 2022). According to an eco-social approach in health promotion, actions at the school level should always be linked with actions in the local community (Laverack, 2020) in order to develop healthy cities that are inclusive, safe and resilient (WHO, 2016). That is the priority assumption of the European network of schools that promote health, which includes 43 European countries since 1992, as well as Italy. An agreement between ASP (Agency Healthcare Local) and the University of Palermo supports, technically and scientifically, the SHE network (called IGEA) of the metropolitan city of Palermo, in the process of building and starting up it. The aim is to implement a structured and systematic plan for the health, well-being and social capital development of all pupils and teaching and non-teaching staff. The partnership between ASP and University of Palermo had enable the realization of this plan trough different phases: 1. Information and sharing of specialist documentation and sources relating to the network of schools that promote health, according to the indications of the European model (SHE network manual and related annexes), disseminating concepts, terminology, assumptions, actions, values, goals and a common language. 2. Analysis of training needs, consisting in the design and implementation of an electronic form for the collection and analysis of preliminary information about the general orientation of schools interested in health issues. 3. Training aimed at school managers, with face-to-face and interactive work sessions, in order to stimulate their awareness of the global model of health, pursued by the SHE network.
4. Group work, composed of all school actors (students, managers, families, technical staff, local stakeholders), to investigate and develop the four components of the SHE Model (healthy school policy, school physical and social environments, community and services links, health personal skills). 5. Drafting of the health plan of each school from a health global perspective. Phases to become / remain a health promoting school will be illustrated and particularly the way in which the process had initiated, upscaled, sustained, and inspired in Palermo and in Sicily, bringing together 18 schools in a new network agreement capable to drive a bottom up decisional process about policy and actions promoting global health
A systematic approach for modeling and identification of eddy current dampers in rotordynamic applications
Eddy current dampers (ECDs) exploit Lorentz forces due to the induced eddy currents in a conductor subject to a time–varying magnetic field. ECDs can be used to introduce damping in rotordynamic applications without mechanical contact to the rotor, thus introducing negligible impact on the dynamic response of the whole system. They are suitable for applications where contactless support of a rotor is required, thus being a perfect match for passive magnetic bearings such as permanent magnet bearings and superconducting bearings. However, modeling and identification of the amount of damping induced by ECDs is a difficult task due to complicated geometry and working conditions. A novel and systematic approach for modeling and identification of the damping characteristics of ECDs in rotordynamic applications is proposed in the present paper. The proposed approach employs an analytical dynamic model of the ECD and curve fitting with results of finite element (FE) models to obtain the parameters characterizing the ECD’s mechanical impedance. The
damping coefficient can be obtained with great accuracy from a single FE simulation in quasi-static conditions. Finally, the accuracy of the identification approach is verified by comparing the results with experimental tests. The validity of this approach is in the cases where ECDs employ an axisymmetric conductor, thus covering most cases in rotordynamic applications
Screening for Tuberculosis in Health Care Workers. Experience in an Italian Teaching Hospital
Health care workers (HCW) are particularly at risk of acquiring tuberculosis (TB), even in countries with low TB incidence. Therefore, TB screening in HCW is a useful prevention strategy in countries with both low and high TB incidence. Tuberculin skin test (TST) is widely used although it suffers of low specificity; on the contrary, the in vitro enzyme immunoassay tests (IGRA) show superior specificity and sensitivity but are more expensive. The present study reports the results of a three-year TB surveillance among HCW in a large teaching hospital in Rome, using TST (by standard Mantoux technique) and IGRA (by QuantiFERON-TB) as first- and second-level screening tests, respectively. Out of 2290 HCW enrolled, 141 (6.1%) had a positive TST; among them, 99 (70.2%) underwent the IGRA and 16 tested positive (16.1%). The frequency of HCW tested positive for TB seems not far from other experiences in low incidence countries. Our results confirm the higher specificity of IGRA, but, due to its higher cost, TST can be considered a good first level screening test, whose positive results should be further confirmed by IGRA before the patients undergo X-ray diagnosis and/or chemotherapy
Rhombohedral R3c to orthorhombic Pnma phase transition induced by Y-doping in BiFeO3
In this work we study, by means of ab initio calculations, the structural, electronic and magnetic properties of Y-doped BiFeO3 compounds. We determine that there is a morphotropic phase boundary at an yttrium concentration of , where the structure changes from R3c to Pnma. This structural transition is driven by the chemical pressure induced by the dopant. By analyzing the evolution of the oxygen octahedral tilts we find an enhanced antiferrodistortive distortion when increasing the Y-doping, together with a reduction of the ferroelectric distorsion, that gives rise to a smaller value of the electric polarization. These cooperative effects should lead to a larger canting of the Fe magnetic moments and to a larger ferromagnetic response in the R3c phase, as it is observed in the experiments.Fil: Graf, MĂłnica Elisabet. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Rosario. Instituto de FĂsica de Rosario. Universidad Nacional de Rosario. Instituto de FĂsica de Rosario; ArgentinaFil: Di Napoli, Solange Mariel. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. ComisiĂłn Nacional de EnergĂa AtĂłmica; ArgentinaFil: Barral, MarĂa Andrea. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentina. ComisiĂłn Nacional de EnergĂa AtĂłmica; ArgentinaFil: Saleh Medina, Leila MarĂa. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; ArgentinaFil: Negri, Ricardo Martin. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Oficina de CoordinaciĂłn Administrativa Ciudad Universitaria. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de QuĂmica, FĂsica de los Materiales, Medioambiente y EnergĂa; ArgentinaFil: Sepliarsky, Marcelo Claudio. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - Rosario. Instituto de FĂsica de Rosario. Universidad Nacional de Rosario. Instituto de FĂsica de Rosario; ArgentinaFil: Llois, Ana Maria. ComisiĂłn Nacional de EnergĂa AtĂłmica; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas; Argentin
The role of internalized transphobia, loneliness, and social supportin thepsychological well-being of a group of Italian transgender and gender non-conforming youths: A moderated-mediation model
The contribution investigates the quality of life of transgender and gender non-conforming (TGNC)people in according to the support received from social and family context. Although TGNC youth represent a highly resilient community capable of successfully overcoming adverse life circumstances, they still experience social stigma that negatively impacts their health (Molnar, 2018), especially if approached
to the possibility of being rejectedby the family and peer group.An additional risk is represented by the common idea that the sex assigned at birth must be aligned with gender identity (Nadal et al., 2012) on which the support (Lev, 2013) can play a role as a moderator.
Objectives of thisresearch are:1) evaluating how internalized transphobia (IT) and loneliness are correlated withthe quality of life; 2) clarifying whether social support would act as a protective factor in the quality of life of research participants. The research used a multimethod approach through a questionnaire divided into 5 sections including 4 different scales (Warwick–Edinburgh Mental Well-being Scale; Gender Minority Stress and Resilience Scale; Multidimensional Scale of Perceived Social Support; Scala Revised University of California at Los Angeles Loneliness Scale). Thus, within the framework of the minority stress, this paper aims to investigate the role of
loneliness as a mediator of the relationship between IT and psychological well-being (PW), as well as the moderating role of social support. A total of 79 Italian TGNC youths (45 binary and 34 non binary) aged 18 to 30 years (M = 23.73, SD = 3.59) participated in an online survey. A moderated mediation model was tested using the PROCESS Macro for SPSS with gender identity and age as control variables. Results showed that: (1)IT was negatively associated with PW(b = -0.03, p = 0.001); (2) IT was positively associated with
loneliness (b = 0.03, p< 0.001); (3) loneliness was negatively associated with PW(b = -0.49, p = 0.001); and (4) loneliness partially mediated the relationship between IT and PW(b = -0.19, p = 0.006). In addition, social support proved to be a significant moderator, as the effect of IT on PW decreased with moderate (b = -0.03, 95% C.I. [-0.04, -0.01], p = 0.001) and high social support (b = -0.04, 95% C.I. [-0.06, -0.01], p < 0.001), but not with low (p< 0.05). Other clinical and social implications of our findings are discussed in terms of individual, interpersonal, and structural stigma.Based on our findings, it is advisable both to expand the social network, promoting intimate
and community relationships, and to take charge, on a clinical level, of the experiences of loneliness that can become radicalized over time also through the early experiences of one's personal and family history
The Role of Internalized Transphobia, Loneliness, and Social Support in the Psychological Well-Being of a Group of Italian Transgender and Gender Non-Conforming Youths
Although transgender and gender non-conforming (TGNC) youth represent a highly
resilient community capable of successfully overcoming adverse life circumstances, they still face
social stigma that negatively impacts their health, being at risk of developing negative feelings toward their own TGNC identity (i.e., internalized transphobia). A poorly investigated dimension in TGNC health research is perceived loneliness. Thus, within the minority stress theory, the present study
aimed to investigate the mediating role of loneliness and the moderating role of social support in the relationship between internalized transphobia and psychological well-being among 79 Italian TGNC youths aged 18 to 30-years-old who participated in an online survey. The main results show that loneliness partially mediated the relationship between internalized transphobia and psychological well-being. In addition, social support emerged as a significant moderator, as the
impact of internalized transphobia on psychological well-being decreased at moderate and high levels of social support, but not at low levels. The findings have significant implications for clinical practice and psychosocial interventions to reduce the impact of internalized stigma and stress on psychological healt
A new partial regularity result for non-autonomous convex integrals with non standard growth conditions
We establish C 1,γ -partial regularity of minimizers of non autonomous convex integral functionals of the type: F(u; Ω) :=´Ω f (x, Du) dx, with non standard growth conditions into the gradient for a couple of exponents p, q such that and α-Hölder continuous dependence with respect to the x variable. The significant point here is that the distance between the exponents p and q is independent of α. Moreover this bound on the gap between the growth and the coercitivity exponents improves previous results in this setting
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