1,722,854 research outputs found
P. Pensabene, M. A. Rizzo, M. Roghi, E. Talamo, Terracotte votive dal Tevere
No full textPailler Jean-Marie. P. Pensabene, M. A. Rizzo, M. Roghi, E. Talamo, Terracotte votive dal Tevere. In: Annales. Économies, Sociétés, Civilisations. 38ᵉ année, N. 4, 1983. pp. 957-958
Sul Pittore di Monaco 833
No full textThe Painter of Munich 833, studied by J.Gy. Szilágyi, who attributed to him 5 vases, has always been closely related
to the Ivy leaf Group. In this article it’s proposed to distinguish two different painters, the first, with the old name of
Painter of Munich 833 more tied to the Attic tradition, for iconography and stylistic models, author of two amphorae
(Munich 833 and tomb 170 Osteria necropolis of Vulci), the second, with the new name of the Symplegma Painter,
nearer to Greek East ceramography for his stylistic models, author of three amphorae (Louvre E723, Metropolitan
Museum 22.139.83 and fragments in Budapest). The Painter of Munich 833 could be an Attic Painter, near to Amasis
and related , moved to Etruria during the second half of the sixth century, around 540-520 B.C
P. Pensabene, M. A. Rizzo, M. Roghi, E. Talamo, Terracotte votive dal Tevere
No full textPailler Jean-Marie. P. Pensabene, M. A. Rizzo, M. Roghi, E. Talamo, Terracotte votive dal Tevere. In: Annales. Économies, Sociétés, Civilisations. 38ᵉ année, N. 4, 1983. pp. 957-958
L’attività del Parco Valle dei Templi al Quartiere Ellenistico Romano. Le ricerche del 2014
No full textThe so-called ‘Quartiere Ellenistico-Romano’ is a part of the ancient settlement of the city of Agrigento where the archaeological excavations were focused as early as the second half of the 19th century. Recent surveys by the ‘Archaeological and Landscape Park of the Valley of the Temple’ was able to collect useful information to a better understanding and definition of the phases of construction, life and abandonment of some domus. New surveys were carried out in Insulae 1 and 4. In the Insula 4, a new area were brought to light some areas relevant to a thermal complex, the first known in the Roman Agrigentum. It is not clear whether it is to be interpreted as a public structure or as a rich private domus and when it was built but it was probably abandoned in the half of 5th century BCE. In the Early Medieval Period some rooms are reoccupied. In the Insula 1, the excavation shows the complexity of the stratification and the transformations of the site between the Late Republican period, when the area of the I C House was occupied by a rich domus with frescoes, and the late antiquity which sees the emergence of a workshops. It was able to acquire new data for the chronological definition of the phases and, at the same time, to clarify the functional use of the East side of the House and in particular of the ‘s’ room. Ernesto De Miro considers the room as a kitchen for the presence at the corner of a quarter circle shaped structure interpreted as a oven. After the 2014 Excavation it is clear that the room was a workshop probably for the production of olive oil. The presence of a workshop into the IC House, very close to the public area of the city, allows us to hypothesize others productive activities located into the housing settlement and open up new perspectives in the study of the district
Theoretical and experimental study on a mechatronic speed variator device for HD Fuel-Injection-Common Rail Pump
Full text linkDa un punto di vista storico, la diffusione e il grande successo dei motori diesel sono dovuti all'introduzione del Common Rail System (CRS). Questo sistema di iniezione ha consentito un preciso dosaggio del carburante attraverso gli niettori agendo sui tempi di iniezione e regolando la pressione common rail. Inoltre, la capacità di controllare la pressione di iniezione ha permesso di eseguire più iniezioni, che è il punto cruciale per il moderno motore diesel per ridurre le emissioni inquinanti.
L'evoluzione del CRS nel tempo è principalmente legata al metodo utilizzato per controllare la pressione del common rail. Inizialmente, la regolazione della pressione common rail veniva eseguita dalla cosiddetta Pressure Control Valve (PCV). Questa valvola veniva montata direttamente sul common rail o, equivalentemente, in uscita alla pompa di alta pressione. Questa topologia garantisce una regolazione rapida e precisa della pressione, scaricando il carburante in eccesso nel serbatoio. L'inconveniente principale di questo approccio è rappresentato dalle fluttuazioni di pressione dovute al funzionamento della valvola, che agiscono da disturbo sul funzionamento degli iniettori. Inoltre, il ricircolo del flusso compresso al serbatoio provoca dissipazione di energia e riscaldamento indesiderato nel serbatoio del carburante.
Per ovviare agli svantaggi della PCV, nel moderno CRS è stata introdotta una Fuel Metering Unit (FMU), che consiste in una valvola montata sulla pompa ad alta pressione per regolarne il flusso in ingresso e quindi controllare la pressione common rail. Questo tipo di regolazione riduce la dissipazione di energia perché la quantità di carburante compresso dalla pompa è esattamente la quantità impostata dalla Engine Control Unit (ECU) per ottenere il corretto rapporto aria / carburante.
La nuova topologia di CRS proposta in questo lavoro, che è ancora in fase di sviluppo, introduce una trasmissione a variazione continua (CVT) tra il motore e la pompa ad alta pressione al posto del tradizionale giunto a ingranaggi. Consente la regolazione della velocità della pompa in base alla pressione common rail richiesta e al flusso di iniezione richiesto, riducendo così le perdite meccaniche nella pompa ad alta pressione.
In questo lavoro, riassumiamo i principali risultati ottenuti studiando l'efficacia di questo nuovo approccio. In particolare, presentiamo la strategia di controllo per un CRS completo dotato di una trasmissione a variazione continua, che è stata validata in simulazione, e un proof of concept sviluppato su una versione semplificata del sistema.From a historical point of view, the diffusion and the great success of diesel engines were induced by the introduction of the Common-Rail System (CRS). This injection system enabled precise metering of the fuel through the injector nozzles by acting on injection timings and by regulating the common-rail pressure. Moreover, the ability to control the injection pressure made it possible to perform multiple injections, which is the crucial point for the modern diesel engine to reduce pollutant emissions.
The evolution of the CRS over time is mostly related to the method used to control the rail pressure. Initially, the common-rail pressure regulation was performed by the so-called Pressure control valve (PCV). This valve was mounted directly on the common-rail or, equivalently, on the outlet port of the pump. This topology ensures a fast and precise regulation of the pressure by discharging the fuel in excess to the tank. The main drawback of this approach is represented by the pressure fluctuations due to the valve functioning, which acts as disturbances on the operation of the injectors. Furthermore, the recirculation of the compressed flow to the tank causes energy dissipation and undesired heating in the fuel tank.
To overcome the disadvantages of the PCV, in the modern CRS was introduced a Fuel Metering Unit (FMU), which consists of a valve mounted on the high-pressure pump to adjusts its inlet flow and thus control the common-rail pressure. This kind of regulation reduces energy dissipation because the quantity of fuel compressed by the pump and delivered to the rail is exactly the quantity set by the ECU to obtain the proper air/fuel ratio.
The new topology of CRS proposed in this work, which is still under development, introduces a Continuously Variable Transmission (CVT) between the engine and the high-pressure pump in place of a conventional gear coupling. It enables the adjustment of the pump speed according to the required common-rail pressure and demanded injection flow, thus reducing mechanical losses in the high-pressure pump.
In this work, we summarize the main results obtained investigating the effectiveness of this novel approach. In particular, we present the control strategy for a complete CRS equipped with a continuously variable transmission, which has been validated in simulation, and a preliminary experimental proof of concept performed on a simplified prototype version of the system
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Molecular endocrinology and metabolism in 2021: What’s new
Full text linkThe last two years, despite the very serious COronaVIrus Disease-2019 (COVID-19) pandemic, have been quite productive in the field of molecular endocrinology and metabolism and our journal section has contributed extensively on that [...]
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