17 research outputs found

    A real time energy management strategy for plug-in hybrid electric vehicles based on optimal control theory

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    Abstract Plug-in hybrid electric vehicles are commonly designed to work in Charge Depleting/Charge Sustaining (CD/CS) mode, depleting the battery by driving in only-electrical mode until the SoC reaches its minimum acceptable threshold, and then sustaining the state of charge till the end of the mission, operating as a traditional hybrid vehicle. Nonetheless, a simple application of an optimal control framework suggests a blended discharge strategy, in which the powertrain is operated as to gradually deplete the SoC and reach the lower threshold only at the end of the trip. Such an algorithm has the drawback that the optimal solution can only be reached offline, depending on the a-priori knowledge of the driving event, making it unsuitable to be implemented online, as it is. The paper presents a methodology to design a heuristic controller, to be used online, based on rules extracted from the analysis of the powertrain behavior under the optimal control solution. The application is a parallel plug-in vehicle, derived from a re- engineered engine-only driven powertrain, and the optimal problem is solved with the Pontryagin's Minimum Principle. Results are also compared to the same vehicle in its standard internal combustion engine version, as well as the commonly implemented Charge Depleting/Charge Sustaining strategy

    Vernal Keratoconjunctivitis: an update focused on clinical grading system

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    Vernal keratoconjunctivitis (VKC) is a severe disease with a prevalence of < 1 case out of 10,000 in Europe, which occurs mainly in pediatric age and is characterized by a severe and often bilateral chronic inflammation of the ocular surface. The diagnosis is generally confirmed by the finding at the ocular examination of conjunctival hyperemia, papillary hypertrophy in the tarsal conjunctiva, giant papillae, papillae in the limbus region

    Focus on cardiologic findings in 30 children with PANS/PANDAS. an italian single-center observational study

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    Objective: Cardiac involvement in PANS has not been clarified relying on the scientific literature available until today. It is known that streptococcal infections play a role in the etiology of a great number of diseases including Sydenham chorea and rheumatic fever, among others. Based on the suspected pathogenesis of PANDAS (Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal infections) reported in the medical literature, we decided to investigate the cardiologic involvement in children with a recent PANS/PANDAS diagnosis. Methods: The study population satisfies PANS (1) and PANDAS (2) criteria of diagnoses. Cardiologic assessment was performed through clinical examination, electrocardiography, and echocardiography. Results: In the selected pediatric population, a significant number of children presented mitral valve involvement, systolic murmurs and electrocardiographic abnormalities. High ASLOT levels did not seem to be associated to a cardiac involvement. Conclusions: Often PANS is difficult to diagnose because it is little known by physicians and most of the cardiologic findings described in this study are common among the healthy pediatric population. Also, ASLOT levels seems not to be predictive of cardiac involvement. Furthermore, the existence of PANDAS as a clinical entity is associated with a group of anti-neuronal autoantibodies found in Sydenham chorea is still controversial. We recommend a complete cardiologic evaluation in those children who meet the PANS/PANDAS diagnostic criteria

    Consensus statement of the Italian society of pediatric allergy and immunology for the pragmatic management of children and adolescents with allergic or immunological diseases during the COVID-19 pandemic

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    The COVID-19 pandemic has surprised the entire population. The world has had to face an unprecedented pandemic. Only, Spanish flu had similar disastrous consequences. As a result, drastic measures (lockdown) have been adopted worldwide. Healthcare service has been overwhelmed by the extraordinary influx of patients, often requiring high intensity of care. Mortality has been associated with severe comorbidities, including chronic diseases. Patients with frailty were, therefore, the victim of the SARS-COV-2 infection. Allergy and asthma are the most prevalent chronic disorders in children and adolescents, so they need careful attention and, if necessary, an adaptation of their regular treatment plans. Fortunately, at present, young people are less suffering from COVID-19, both as incidence and severity. However, any age, including infancy, could be affected by the pandemic. Based on this background, the Italian Society of Pediatric Allergy and Immunology has felt it necessary to provide a Consensus Statement. This expert panel consensus document offers a rationale to help guide decision-making in the management of children and adolescents with allergic or immunologic diseases

    Preliminary Design and Simulation of a Turbo Expander for Small Rated Power Organic Rankine Cycle (ORC)

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    Nowadays, the Organic Rankine Cycle (ORC) system, which operates with organic fluids, is one of the leading technologies for “waste energy recovery”. It works as a conventional Rankine Cycle but, as mentioned, instead of steam/water, an organic fluid is used. This change allows it to convert low temperature heat into electric energy where required. Large numbers of studies have been carried out to identify the most suitable fluids, system parameters and the various configurations. In the present market, most ORC systems are designed and manufactured for the recovery of thermal energy from various sources operating at “large power rating” (exhaust gas turbines, internal combustion engines, geothermal sources, large melting furnaces, biomass, solar, etc.); from which it is possible to produce a large amount of electric energy (30 kW ÷ 300 kW). Such applications for small nominal power sources, as well as the exhaust gases of internal combustion engines (car sedan or town, ships, etc.) or small heat exchangers, are very limited. The few systems that have been designed and built for small scale applications, have, on the other hand, different types of expander (screw, scroll, etc.). These devices are not adapted for placement in small and restricted places like the interior of a conventional car. The aim of this work is to perform the preliminary design of a turbo expander that meets diverse system requirements such as low pressure, small size and low mass flow rates. The expander must be adaptable to a small ORC system utilizing gas of a diesel engine or small gas turbine as thermal source to produce 2–10 kW of electricity. The temperature and pressure of the exhaust gases, in this case study (400–600 °C and a pressure of 2 bar), imposes a limit on the use of an organic fluid and on the net power that can be produced. In addition to water, fluids such as CO2, R134a and R245fa have been considered. Once the operating fluids has been chosen, the turbine characteristics (dimensions, input and output temperature, pressure ratio, etc.) have been calculated and an attempt to find the “nearly-optimal” combination has been carried out. The detailed design of a radial expander is presented and discussed. A thermo-mechanical performance study was carry out to verify structural tension and possible displacement. On the other hand, preliminary CFD analyses have been performed to verify the effectiveness of the design procedure.Nowadays, the Organic Rankine Cycle (ORC) system, which operates with organic fluids, is one of the leading technologies for “waste energy recovery”. It works as a conventional Rankine Cycle but, as mentioned, instead of steam/water, an organic fluid is used. This change allows it to convert low temperature heat into electric energy where required. Large numbers of studies have been carried out to identify the most suitable fluids, system parameters and the various configurations. In the present market, most ORC systems are designed and manufactured for the recovery of thermal energy from various sources operating at “large power rating” (exhaust gas turbines, internal combustion engines, geothermal sources, large melting furnaces, biomass, solar, etc.); from which it is possible to produce a large amount of electric energy (30 kW ÷ 300 kW). Such applications for small nominal power sources, as well as the exhaust gases of internal combustion engines (car sedan or town, ships, etc.) or small heat exchangers, are very limited. The few systems that have been designed and built for small scale applications, have, on the other hand, different types of expander (screw, scroll, etc.). These devices are not adapted for placement in small and restricted places like the interior of a conventional car. The aim of this work is to perform the preliminary design of a turbo expander that meets diverse system requirements such as low pressure, small size and low mass flow rates. The expander must be adaptable to a small ORC system utilizing gas of a diesel engine or small gas turbine as thermal source to produce 2–10 kW of electricity. The temperature and pressure of the exhaust gases, in this case study (400–600 °C and a pressure of 2 bar), imposes a limit on the use of an organic fluid and on the net power that can be produced. In addition to water, fluids such as CO2, R134a and R245fa have been considered. Once the operating fluids has been chosen, the turbine characteristics (dimensions, input and output temperature, pressure ratio, etc.) have been calculated and an attempt to find the “nearly-optimal” combination has been carried out. The detailed design of a radial expander is presented and discussed. A thermo-mechanical performance study was carry out to verify structural tension and possible displacement. On the other hand, preliminary CFD analyses have been performed to verify the effectiveness of the design procedure

    PROPOSAL DESIGN PROCEDURE AND PRELIMINARY SIMULATION OF TURBO EXPANDER FOR SMALL SIZE (2-10 KW) ORGANIC RANKINE CYCLE (ORC)

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    Currently, one of the leading technologies for the "energy recovery" adopting a Rankine cycle (ORC) with organic fluids. ORC system operates like a conventional Rankine cycle, but instead of steam/water, uses an organic fluid. This change allows to convert low temperature heat and generate, where required, electricity. A large amount of studies were carried out to identify the most suitable fluids, system parameters and the various configurations. In reality, most ORC systems are designed and manufactured for recovery of thermal energy from various sources but at "large power rating" (exhaust gas turbines, internal combustion engines, geothermal sources, large melting furnaces, biomass, solar, etc.) from where it is possible to produce electric energy (30kW / 300kW), but for the application of this system for small nominal power, as well as the exhaust gases of internal combustion engines (car sedan or town, ships, etc.) or smaller heat exchangers, there are very few applications. The aim of this work is to design a turbo-expander that meets system requirements: low pressure, small size, low mass flow rates. The Expander must be adaptable to a small ORC system utilizing gas of a diesel engine or small gas turbine to produce 2-10 kW of electricity. The temperature and pressure of the exhaust gases, in this case study (400-600°C and at a pressure of 2 bar), imposes a limit on the use of an organic fluid and on the net power that can be produced. In addition to water, organic fluids such as CO2, R134a and R245fa have been considered. Once the fluid has been chosen operating, the turbine characteristics (dimensions, temperature, input and output pressure ratio, etc.) have been calculated and an attempt to find the "nearly-optimal" has been carried out. The detailed design of radial Expander is presented and discussed. An initial thermo-mechanical performance study is carried out to verify structural tension and possible displacement. Next step of the research here proposed will be the CFD simulation to improve or modify the chosen blade profile. Copyright © 2014 by ASME

    Existence results for strong vector equilibrium problems and their applications

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    New existence results for the strong vector equilibrium problem are presented,relying on a well-known separation theorem in infinite-dimensional spaces. The main results are applied to strong cone saddle-points and strong vector variational inequalities providing new existence results, and furthermore they allow recovery of an earlier result from the literature

    Analisi dello scenario idrogeologico per la modellazione del flusso sotterraneo nell'area della nuova Stazione di S. Giovanni (Roma), Metro C- tratta T4

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    La nuova stazione di San Giovanni, in corrispondenza della quale la tratta T4 della linea C della Metropolitana intersecherà la linea A, verrà realizzata all’interno di allineamenti di paratie a diaframmi in calcestruzzo che si attesteranno completamente nella formazione delle argille plioceniche, condizionando il flusso delle falde superficiale e profonda presenti nella zona oggetto di studio. Utilizzando il software Visual Modflow, è stato realizzato il modello numerico delle acque sotterranee dell’area interessata dalla nuova stazione allo scopo di valutare la possibile interferenza che l’opera prevista in progetto può generare con gli acquiferi soggiacenti e le criticità che ne possono derivare. Particolare attenzione richiede il rialzo piezometrico dovuto all’adattamento dell’acquifero alla presenza della nuova struttura. Per la falda superficiale, il massimo valore di rigurgito a monte calcolato dal modello si assesta a ca. 10 cm mentre la depressione a valle raggiunge valori di ca. 12 cm. Per la falda profonda, il massimo valore di rigurgito a monte calcolato si assesta a ca. 10 cm mentre la depressione a valle raggiunge valori di ca. 10 cm. La regione influenzata dallo sbarramento risulta circoscritta intorno all’opera in un’area di circa 0.1 km2 di innalzamento a nord e a est della stazione (monte flusso) e 2.5 km2 a sud e a ovest della stazione (valle flusso). L’effetto che l’opera eserciterà sul regime di falda avviene in gran parte nei primi 100 gg, dopodiché le differenze di piezometria si vanno attenuando fino a stabilizzarsi dopo circa 10 anni dalla costruzione dell’opera stessa
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