Analysis of the Dynamic Behavior of a Counterbalance Forklift Truck through Multibody Modelling and Simulation

This work deals with the analysis of the dynamic response of a counterbalance forklift truck prototype when performing standard verification maneuvers, defined by the manufacturer’s testing protocols. The research aims at developing numerical tools based on multibody models to predict accurately the dynamic loads acting on the forklift in the conditions of interest. In particular, this study focuses on a specific test condition, namely the passage on a steel plate obstacle at constant speed, which is one of the most severe maneuvers of the reference cycle in terms of dynamic loads. A model of the complete forklift is developed inside a commercial multibody environment. It takes into account the ground/tire interactions, by means of a simplified nonlinear contanct model, and the load handling assembly dynamics. An experimental campaign is designed and conducted to asses the vehicle behavior when running on the obstacle, by measuring the vibrations of the chassis and of the mast, as well as the forces generated by the mast tilting actuators. The measured data are exploited for model update and validation. The numerical results provided by the updated model show a satisfactory accuracy

Lensing gravitazionale di particelle massive

Il lensing gravitazionale è uno strumento molto potente per indagare l'universo e le teorie della gravità. In questa tesi si estende il formalismo del lensing gravitazionale a particelle massive. I risultati ottenuti in questa tesi sono generali e il formalismo utilizzato può essere applicato ad altri tipi di particelle dotate di massa. Nel capitolo 1 si forniscono i concetti matematico-fisici per poter approfondire la trattazione del fenomeno di lensing. Nel capitolo 2 si ricava la metrica di Schwarzschild e si fornisce una trattazione generale delle geodetiche in questo spazio-tempo. Nel capitolo 3 si ricava un'espressione originale per l'angolo di deflessione per particelle massive. Il risultato innovativo di questa tesi consiste nell'aver risolto l'equazione delle geodetiche per l'angolo di deflessione di particelle dotate di massa nella metrica di Schwarzschild. Tale risultato è stato ottenuto nel limite di deflessione debole ("weak deflection limit" ) con un metodo perturbativo applicando le approssimazioni di campo debole e velocità prossime a quelle della luce. Nel capitolo 4 viene discusso il fenomeno del lensing gravitazionale trattando le sue proprietà. In particolare nel caso di lente puntiforme vengono presentate formule generalizzate per la posizione e l'amplicazione delle immagini. Nel capitolo 5 viene calcolato l'angolo di deflessione riferito al lensing di fotoni da parte del Sole e al lensing di neutrini da parte di stelle. Successivamente viene proposto un esperimento teorico considerando un sistema di lensing cosmologico nel quale la sorgente di neutrini è un blazar mentre la lente è rappresentata da un ammasso di galassie. Le scelte delle distanze tra osservatore, ammasso di galassie e blazar, dell'ammasso di galassie come lente e dell'energia del fascio di neutrini (eV) sono tali da massimizzare le correzioni al lensing di fotoni

Direct numerical simulation of the flow around an aerofoil in ramp-up motion

A detailed analysis of the flow around a NACA0020 aerofoil at Rec = 2 × 104 undergoing a ramp up motion has been carried out by means of direct numerical simulations. During the manoeuvre, the angle of attack is linearly varied in time between 0° and 20° with a constant rate of change of αrad = 0.12 U∞/c. When the angle of incidence has reached the final value, the lift experiences a first overshoot and then suddenly decreases towards the static stall asymptotic value. The transient instantaneous flow is dominated by the generation and detachment of the dynamic stall vortex, a large scale structure formed by the merging of smaller scales vortices generated by an instability originating at the trailing edge. New insights on the vorticity dynamics leading to the lift overshoot, lift crisis, and the damped oscillatory cycle that gradually matches the steady condition are discussed using a number of post-processing techniques. These include a detailed analysis of the flow ensemble average statistics and coherent structures identification carried out using the Q-criterion and the finite-time Lyapunov exponent technique. The results are compared with the one obtained in a companion simulation considering a static stall condition at the final angle of incidence α = 20°

Analysis of environmental impacts of a pump-storage system between two Norwegian reservoirs considering climate scenarios

publishedVersio

Allaboard a system for exploring urban mobility and optimizing public transport using cellphone data

The deep penetration of mobile phones offers cities the ability to opportunistically monitor citizens interactions and use data-driven insights to better plan and manage services. In this context, transit operators can leverage pervasive mobile sensing to better match observed demand for travel with their service offerings. With large scale data on mobility patterns, operators can move away from the costly and resource intensive transportation planning processes prevalent in the West, to a more data-centric view, that places the instrumented user at the center of development. In this framework, using mobile phone data to perform transit analysis and optimization represents a new frontier with significant societal impact, especially in developing countries. Document type: Part of book or chapter of boo

Genesi di comunità educative fra creatività e orizzonti di senso. Una ricerca con le scuole in Emilia-Romagna

A partire da una ricerca empirica di durata triennale svolta presso alcune scuole statali e paritarie dell'Emilia-Romagna, il volume tematizza nodi cruciali della competenza docente e della sua formazione iniziale e in servizio: creatività, orizzonti di senso e sfera emotivo-affettiva, pratiche induttivo-laboratoriali, comunità di pratica. Il tentativo è quello di restituire la ricca complessità dell'azione di insegnamento e, contemporaneamente, di delineare alcune "direttrici di senso pedagogico" che consentano di riconoscere le comunità educative che operano ed interagiscono nella scuola

Multisystem autoimmune disease caused by increased STAT3 phosphorylation, and dysregulated gene expression

Signal transducer and activator of transcription (STAT) 3 is a member of the STAT family, and plays a major role in various immunological mechanisms.1 Mutations in STAT3 are associated with a broad spectrum of manifestations, including immunodeficiency, autoimmunity, and malignancy.2 In particular, heterozygous germline loss-of-function (LOF) mutations cause Hyper-IgE syndrome (HIES),3–5 while heterozygous germline gain-of-function (GOF) mutations have recently been associated to multi-organ autoimmune manifestations (i.e. type 1 diabetes, enteropathy, cytopenia, interstitial lung disease, hypothyroidism), lymphoproliferation, short stature, and recurrent infections (OMIM #615952).6–8 We report a 7-year-old boy who presented with early-onset severe enteropathy, and diffuse eczematous dermatitis since birth. During the first weeks of life, Hirschsprung disease was also suspected and surgically treated. Gastrointestinal and cutaneous manifestations were first ascribed to food allergy with quite a good response to amino acid-based formula. In the following months, the patient failed to thrive, and developed respiratory tract infections. At two years, the patient presented with progressive interstitial lung disease characterized by lymphocytic interstitial infiltration leading to pulmonary hypertension, tricuspid insufficiency, and right ventricular heart failure with hepatomegaly. Because of the increased risk of infections, he received intravenous (IV) immunoglobulin infusions (400 mg/kg), prophylaxis with cotrimoxazole and fluconazole. Methylprednisolone at 0.3 mg/kg/day was also given to treat autoimmune manifestations

Biological Role and Clinical Implications of microRNAs in BRCA Mutation Carriers

Women with pathogenic germline mutations in BRCA1 and BRCA2 genes have an increased risk to develop breast and ovarian cancer. There is, however, a high interpersonal variability in the modality and timing of tumor onset in those subjects, thus suggesting a potential role of other individual’s genetic, epigenetic, and environmental risk factors in modulating the penetrance of BRCA mutations. MicroRNAs (miRNAs) are small noncoding RNAs that can modulate the expression of several genes involved in cancer initiation and progression. MiRNAs are dysregulated at all stages of breast cancer and although they are accessible and evaluable, a standardized method for miRNA assessment is needed to ensure comparable data analysis and accuracy of results. The aim of this review was to highlight the role of miRNAs as potential biological markers for BRCA mutation carriers. In particular, biological and clinical implications of a link between lifestyle and nutritional modifiable factors, miRNA expression and germline BRCA1 and BRCA2 mutations are discussed with the knowledge of the best available scientific evidence

Numerical Simulation of a Passive Control of the Flow Around an Aerofoil Using a Flexible, Self Adaptive Flaplet

© 2018 The Author(s) Self-activated feathers are used by almost all birds to adapt their wing characteristics to delay stall or to moderate its adverse effects (e.g., during landing or sudden increase in angle of attack due to gusts). Some of the feathers are believed to pop up as a consequence of flow separation and to interact with the flow and produce beneficial modifications of the unsteady vorticity field. The use of self adaptive flaplets in aircrafts, inspired by birds feathers, requires the understanding of the physical mechanisms leading to the mentioned aerodynamic benefits and the determination of the characteristics of optimal flaps including their size, positioning and ideal fabrication material. In this framework, this numerical study is divided in two parts. Firstly, in a simplified scenario, we determine the main characteristics that render a flap mounted on an aerofoil at high angle of attack able to deliver increased lift and improved aerodynamic efficiency, by varying its length, position and its natural frequency. Later on, a detailed direct numerical simulation analysis is used to understand the origin of the aerodynamic benefits introduced by the flaplet movement induced by the interaction with the flow field. The parametric study that has been carried out, reveals that an optimal flap can deliver a mean lift increase of about 20% on a NACA0020 aerofoil at an incidence of 20 o degrees. The results obtained from the direct numerical simulation of the flow field around the aerofoil equipped with the optimal flap at a chord Reynolds number of 2 × 10 4 shows that the flaplet movement is mainly induced by a cyclic passage of a large recirculation bubble on the aerofoil suction side. In turns, when the flap is pushed downward, the induced plane jet displaces the trailing edge vortices further downstream, away from the wing, moderating the downforce generated by those vortices and regularising the shedding cycle that appears to be much more organised when the optimal flaplet configuration is selected