280 research outputs found
The Fermi Large Area Telescope
Get PDFThe Large Area Telescope, the primary instrument on the Fermi Gamma-ray Space
Telescope, is an imaging, wide field-of-view gamma-ray telescope. After many
improvements to the data acquisition and event analysis procedures, it now
covers the broad energy range from MeV to TeV. After more
than 13 years of operation since its launch in June 11, 2008, it has provided
the best-resolved and deepest portrait of the gamma-ray sky. In this chapter we
review the design of the instrument, the data acquisition system, calibration,
and performance.Comment: 30 pages, 11 figures; Invited chapter for Handbook of X-ray and
Gamma-ray Astrophysics (Eds. C. Bambi and A. Santangelo, Springer Singapore,
expected in 2022
CAPRI versus AGLINK-COSIMO: Two partial equilibrium models - Two baseline approaches
Get PDFThe agricultural modelling world has generated several models aiming at the analysis of the response of the sector to certain changes in exogenous mainly policy variables. Among those, the CAPRI modelling system developed by a consortium centred on the University of Bonn and the AGLINK-COSIMO model, a joint product of the OECD and the FAO, are well known and accepted as comprehensive tools. This analysis focuses on a qualitative comparison of both models and particularly on the process of setting up the baseline. The baseline is a medium-term projection of agricultural markets reflecting current policies and those already decided upon. This projection in turn serves as the base for comparisons when analyzing scenarios. It is shown that CAPRI uses generic and automatic procedures whenever possible for conducting the database and the baseline, while AGLINK-COSIMO puts more emphasis on expert knowledge in this process. Both approaches are shown to have certain advantages while the conclusion that a combination of them would potentially improve both models will be drawn from this analysis.CAPRI, AGLINK-COSIMO, Baseline process, Agricultural and Food Policy,
Generatori fotovoltaici dinamici: aspetti tecnici e valutazioni economiche per il loro impiego
No full textLa strategia adottata da molte nazioni, europee e non, di affidare la produzione dell’energia elettrica ad un insieme equilibrato di fonti energetiche ha determinato un incremento delle attività di ricerca anche per lo sfruttamento della risorsa solare. Queste attività intraprese dalla comunità scientifica e seguite con attenzione dal mondo imprenditoriale si sono concentrate sulle tecniche e metodologie innovative di conversione della fonte, sulla concentrazione della radiazione solare nel punto di collocazione del dispositivo di conversione o ancora sull’ottimizzazione dell’orientamento del dispositivo rispetto alla direzione della radiazione. Questo lavoro focalizza la sua attenzione su gli inseguitori solari, dispositivi di semplice applicazione, basati su tecnologie consolidate, la cui diffusa applicazione potrebbe portare, in breve termine, ad un rilevante incremento di energia prodotta da fonte solare.
In particolare questo lavoro, sulla base di indici economici, mira a valutare, al diversificarsi delle taglie degli impianti fotovoltaici e degli inseguitori per essi adottati, quale incremento di producibilità deve essere garantito dall’inseguitore al fine di rendere il suo impiego economicamente vantaggioso per l’investitore
Algebraic Real-Time Algorithm for B-Spline Sinusoidal Pulse Width Modulation in Three Phase Voltage Source Inverters
No full textImplementation and experimental validation of a real-time PWM algorithm based on B-Spline carriers for three phase voltage source inverters
No full textThis paper presents the implementation and experimental results of an algebraic real-time sinusoidal pulse width modulation algorithm (SPWM) based on B-Spline carriers. B-spline functions are used as carrier signals with the aim to to reduce harmonic content of the three phase inverter output voltage. The presented algorithm eliminates the problem of B-spline recursive evaluation with convolution integrals or convolution sums in digital counterpart. The pulse pattern synthesis is made with the help pre-calculated duty cycle expressions. In this way there is no real need to synthesize the carrier signal so the hardware and the whole inverter control system becomes cheaper, more reliable and affordable. The proposed implementation Algorithm effectiveness is finally verified by means of experimental tests in different operating condition (e.g. for different values of the amplitude modulation index and for different values of the power factor) of a three phase inverter
A Micro Wind Generation System for Local DoS Applications
No full textIn this paper a wind electrical power generation system for Distributed on Site (DoS) applications is proposed. This system was developed and conceived in order to guarantee simple installation, use and service, obtaining a product that can be easily industrialized and put into the market with limited costs. The field of application of such an electrical generation system is addressed towards domestic or at the most toward condominium applications concerning moreover the opportunity of working in addition to combined photovoltaic and solar-thermal systems to enhance the renewable energy generation at house level (DoS).
The proposed system has its hot spot in the blades shape, in the wind flux canalization system and in the permanent magnet synchronous generator (PMSG) optimized for this specific purpose. In fact with the proposed system intends to search the best aerodynamic profile and electrical generator to ensure the slightest encumbrance and the lowest weight. For this purpose the traditional and classical tangential wind turbine design, equipped with large blades, is overturned in favour of the use of numerous little blades. A further peculiarity of the system is the expected increase of its efficiency thanks to the presence of the wind flux channelling system with the elimination of the part opposing the wind and thanks to the adoption of a specifically designed PMSG
Dynamics photovoltaic generators: Technical aspects and economical valuation
No full textThe strategy adopted from many European nations and not, to entrust the electric energy production to differently energetic sources has determined an increment of the scientific research for the solar resource exploitation. These scientific community activities follows with attention from the entrepreneurial world have concentrated on the innovative techniques and methodologies of the source conversion, solar concentration and the direction's device optimization. This job focuses its attention on the simple application of solar-track device, based on consolidated technologies. The diffused application of these dispositive, could be, shortly, an important increment of electricity generation energy from solar source. In particular this job estimates, with economic indices and for different size of the photovoltaic systems and of the solar-track devices, the increment of electricity generation to guarantee its economically favorable for the investor
Back-EMF Sensorless Control Algorithm for High Dynamics Performances PMSM
No full textIn the paper a low time consuming and cost sensorless control algorithm for high dynamics performances Permanent Magnet Synchronous Motors (PMSM) both surface or internal permanent magnet mounted for position and speed estimation is introduced discussed and experimentally validated. This control algorithm is based on the estimation of rotor speed and angular position starting from the back electromotive force space vector determination without voltage sensors by using the reference voltages given by the current controllers instead of the actual ones. This choice obviously introduces some errors that must be vanished by means of a compensating function. The novelties of the proposed estimation algorithm are the position estimation equation and the process of compensation of the inverter phase lag that also suggests the final mathematical form of the estimation. The mathematical structure of the estimation guarantees a high degree of robustness against parameters variation as shown by the sensitivity analysis reported in the paper. Experimental verifications of the proposed sensorless control system have been made with the aid of a flexible test bench for Brushless Motor Electrical Drives. The test results presented in the paper show the validity of the proposed low cost sensorless control algorithm and, above all, underline the high dynamic performances of the sensorless control system also with a reduced equipment
Sensorless control of permanent magnet synchronous motors for wide speed range applications
No full textThis paper deals with sensorless control of Interior Permanent Magnet Synchronous Motors (IPMS) based on the estimation of speed and rotor angular position. The above estimate is based on the injection of high frequency stator currents able to generate a signal similar to that generated by a resolver connected to the axis of the motor. A new digital algorithm has been designed to demodulate the above signal whose implementation can be carried out on the same DSP that processes the control algorithm. In this paper a new scheme of speed and angular position estimator is proposed and justified on the theoretic point of view. The experimental results here shown validate the effectiveness of the sensorless control algorithm in all the operating situations concerning the whole speed and load torque ranges
Prime osservazioni sul rapporto tra il reato di “Diffusione illecita di immagini o video sessualmente espliciti” e le libertà di corrispondenza e di manifestazione del pensiero
Get PDFL’articolo concerne il rapporto tra il reato di “Diffusione illecita di immagini o video sessualmente espliciti” (art. 612-ter c.p.) e le libertà costituzionali di corrispondenza (art. 15 Cost.) e di manifestazione del pensiero (art. 21 Cost.). Nello specifico, l’Autore si chiede se il reato di cui all’art. 612-ter incida sulle libertà di cui all’art. 15 e all’art. 21
Cost. Invero, l’unico obiettivo del reo è quello di ledere l’identità morale e l’onorabilità della vittima. Per questo motivo, non deve indurre in errore la circostanza che la condotta descritta dall’art. 612-ter verrà (esclusivamente) posta in essere utilizzando mezzi di comunicazione, deputati alla trasmissione del pensiero. Infatti, l’Autore ritiene che il fondamento costituzionale dell’art. 612-ter c.p. è da rinvenirsi negli artt. 2, 3 e 13 (intesa quale libertà di autodeterminarsi) Cost., mentre la libertà di corrispondenza e la libertà di manifestazione del pensiero non vengono compresse dal reato in esame.The paper concerns the relationship between the crime of “Illicit distribution of sexually explicit images or videos” (Article 612-ter of the Italian Criminal Code) and the constitutional freedoms of correspondence and expression of thought.
Specifically, the Author reflects on whether the offence under art. 612-ter affects the freedoms pursuant to Article 15 and Article 21 of the Constitution. Indeed, the offender’s sole objective is to damage the victim’s moral identity and reputation. For this reason, we should not be misled by the fact that the conduct targeted in Article 612-ter may (exclusively) be implemented using means of communication designed for the transmission of thought. In fact, the Author believes that the constitutional foundation for art. 612-ter of the Italian Criminal Code is to be found in Articles 2, 3 and 13 of the Constitution (regarding the freedom of self-determination), while the freedom of correspondence and freedom of expression of thought are not restricted by the crime in question
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