770 research outputs found

    [Collezioni Numismatiche Valerio Traverso di Genova, Mr Joseph Martini of N. Y. Monate greche e Romano]

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    [Vente. Numismatique. 1931-02-25. Milan][Collection. Numismatique. Traverso, Valerio. 1931][Collection. Numismatique. Martini, Joseph. 1931]Avec mode text

    Numerical Performance Investigation of a Hybrid eCVT Specialized Agricultural Tractor

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    The need for highly efficient agricultural machineries is increasing the interest of the research community and of industrial manufacturers towards the use of integrated electric systems in combination with traditional powertrain elements. In this work, a hybrid electric tractor with electric continuously variable transmission (eCVT) capabilities was studied to investigate their performance in comparison with that of traditional diesel-powered tractor designs. This hybrid electric configuration can be classified as a power-split architecture that aims to combine the best characteristics of both the simpler parallel and the series hybrid layout while minimizing their main drawbacks. An eCVT configuration can allow for optimizing the diesel operating point with respect to the current working conditions, and achieving peak power performance and energy saving with relatively small electric machines. The proposed hybrid eCVT (HeCVT) tractor architecture was studied using a numerical model that allowed for developing two different control strategies: a charge depleting mode enabling the driver to use full power for the most power-intensive scenarios and a charge sustaining mode developed to optimize efficiency and battery use along an entire work day. To test the proposed architecture, several tasks derived from experimental field measurements on a specialized agricultural tractor were used. HeCVT results were compared with a numerical model of the traditional tractor validated by these experimental data. The HeCVT tractor showed good performance in terms of peak power capabilities using a downsized diesel engine, and consistent fuel savings were obtained according to typical daily working scenarios

    Analysis of Fuel Cell Systems for Off-Road Agricultural Vehicles

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    L'abstract è presente nell'allegato / the abstract is in the attachmen

    Hermann Kant. Ein bio- bibliografisches Profil

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    The proximity to the power apparatus has cast dark shadows on the literary work of Hermann Kant, who is regarded as one of the most read authors of the GDR. Valerio Furneri embeds Kant's life and work in the all-German context of the 20th century and reinterprets his classics such as Die Aula or Der Aufenthalt. The author does not pursue the claim to rehabilitate the GDR, nor to trivialise Kant's role in it. Instead, the attempt is made to look at Kant's entire work from a temporal distance and to re-evaluate it. Through his works, Kant was able to accompany and depict not only the German-German history, but also European history.Die Nähe zum Machtapparat hat dunkle Schatten auf das literarische Werk von Hermann Kant, der als meistgelesener Schriftsteller der DDR gilt, geworfen. Valerio Furneri bettet Kants Leben und Werk in den gesamtdeutschen Kontext des 20. Jahrhunderts ein und interpretiert vor diesem Hintergrund Klassiker wie Die Aula oder Der Aufenthalt neu. Der Autor verfolgt dabei weder den Anspruch, die DDR zu rehabilitieren, noch Kants Rolle darin kleinzureden. Stattdessen wird der Versuch unternommen, Kants Gesamtwerk aus zeitlicher Distanz zu betrachten und neu zu bewerten. Durch seine Werke gelang es Kant nämlich nicht nur die deutsch-deutsche, sondern auch die europäische Geschichte zu begleiten und abzubilden

    Hermann Kant. Ein bio- bibliografisches Profil

    No full text
    The proximity to the power apparatus has cast dark shadows on the literary work of Hermann Kant, who is regarded as one of the most read authors of the GDR. Valerio Furneri embeds Kant's life and work in the all-German context of the 20th century and reinterprets his classics such as Die Aula or Der Aufenthalt. The author does not pursue the claim to rehabilitate the GDR, nor to trivialise Kant's role in it. Instead, the attempt is made to look at Kant's entire work from a temporal distance and to re-evaluate it. Through his works, Kant was able to accompany and depict not only the German-German history, but also European history.Die Nähe zum Machtapparat hat dunkle Schatten auf das literarische Werk von Hermann Kant, der als meistgelesener Schriftsteller der DDR gilt, geworfen. Valerio Furneri bettet Kants Leben und Werk in den gesamtdeutschen Kontext des 20. Jahrhunderts ein und interpretiert vor diesem Hintergrund Klassiker wie Die Aula oder Der Aufenthalt neu. Der Autor verfolgt dabei weder den Anspruch, die DDR zu rehabilitieren, noch Kants Rolle darin kleinzureden. Stattdessen wird der Versuch unternommen, Kants Gesamtwerk aus zeitlicher Distanz zu betrachten und neu zu bewerten. Durch seine Werke gelang es Kant nämlich nicht nur die deutsch-deutsche, sondern auch die europäische Geschichte zu begleiten und abzubilden

    Comparative Analysis of Hybrid Electric Architectures for Specialized Agricultural Tractors

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    In this work, a comparative numerical analysis between the performance of a conventional specialized orchard tractor and those of three different hybrid electric tractor configurations is presented. The aim was to compare several powertrain configurations in the same working scenarios derived from field measurements. Peak power capabilities and endurance were numerically tested with specific load scenarios involving both transportation mission profiles and field activities with external implements powered through the power take off of the tractor. The proposed hybrid architectures were configured with the same battery-based energy storage system to perform the comparison with the same energy storage capabilities. Two parallel, two series and one electro-hydraulic hybrid configuration were modeled and tested through simulations. The parallel ones excelled in peak power performance, whereas the series configurations had the highest fuel savings. The electro-hydraulic configuration was proposed as an alternative able to allow for a downsized engine but also for the introduction of the Continuously Variable Transmission (CVT) functionality, which is always an interesting feature for such working machines

    Design and Experimental Validation of a Scaled Test Bench for the Emulation of a Hybrid Fuel Cell Powertrain for Agricultural Tractors

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    Hybrid fuel cell powertrains are a promising strategy to reduce the environmental impact of vehicles and non-road mobile machinery. To preserve the state-of-health of fuel cells, an energy storage system with sufficient power capacity, such as ultra-capacitors or batteries, should be introduced in the system to help the fuel cell during sudden and abrupt changes in power demands. However, the presence of two or more energy sources necessitates the development of an energy management strategy. The energy management strategy should properly split the power request between the different energy sources. In this paper, the design and the experimental validation of a scaled test bench for the emulation of a fuel cell/battery powertrain for a vehicular application is presented. The fuel cell is emulated through an analogically controlled DC power source that reproduces its real voltage–current curve. To split the power between the emulated fuel cell and the batteries, controlled DC-DC is used and a simple energy management strategy based on a proportional-integral controller is developed. The external load is reproduced using a load unit composed of a programmable electronic load and a power supply. Experimental tests are performed to evaluate the system behaviour and to characterize its main components. The experimental results show that the system successfully emulates the powertrain in accordance with the proposed energy management strategy

    Carbon Footprint Enhancement of an Agricultural Telehandler through the Application of a Fuel Cell Powertrain

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    The growing awareness about climate change and environmental pollution is pushing the industrial and academic world to investigate more sustainable solutions to reduce the impact of anthropic activities. As a consequence, a process of electrification is involving all kind of vehicles with a view to gradually substitute traditional powertrains that emit several pollutants in the exhaust due to the combustion process. In this context, fuel cell powertrains are a more promising strategy, with respect to battery electric alternatives where productivity and endurance are crucial. It is important to replace internal combustion engines in those vehicles, such as the those in the sector of Non-Road Mobile Machinery. In the present paper, a preliminary analysis of a fuel cell powertrain for a telehandler is proposed. The analysis focused on performance, fuel economy, durability, applicability and environmental impact of the vehicle. Numerical models were built in MATLAB/Simulink and a simple power follower strategy was developed with the aim of reducing components degradation and to guarantee a charge sustaining operation. Simulations were carried out regarding both peak power conditions and a typical real work scenario. The simulations’ results showed that the fuel cell powertrain was able to achieve almost the same performances without excessive stress on its components. Indeed, a degradation analysis was conducted, showing that the fuel cell system can achieve satisfactory durability. Moreover, a Well-to-Wheel approach was adopted to evaluate the benefits, in terms of greenhouse gases, of adopting the fuel cell system. The results of the analysis demonstrated that, even if considering grey hydrogen to feed the fuel cell system, the proposed powertrain can reduce the equivalent CO2 emissions of 69%. This reduction can be further enhanced using hydrogen from cleaner production processes. The proposed preliminary analysis demonstrated that fuel cell powertrains can be a feasible solution to substitute traditional systems on off-road vehicles, even if a higher investment cost might be required

    Comparative analysis of hybrid fuel cell powertrain architectures for orchard tractors using hardware-in-the-loop technique

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    Fuel cell systems represent a possible solution to improve the sustainability of vehicles requiring high endurance and compactness. Three different powertrains for an orchard tractor are proposed. The proposed systems feature the same fuel cell unit, but different auxiliary sources: a battery pack, a supercapacitor module and a hybrid unit comprising both. Furthermore, to make a fair comparison, the three architectures are designed considering the same overall volume. After defining the architectures, different rule-based strategies, namely power follower and fuzzy logic strategies, are defined to determine the power split among the different sources. Then, the three architectures are tested using a scaled Hardware-in-the-loop test bench according to typical work scenarios. The load profiles are derived from experimental data collected on a commercial orchard tractor. The architectures and energy management strategies are compared considering fuel economy and components durability. Analysing the results, the topology featuring the battery pack as additional power unit shows the higher lifetime expectancy for the fuel cell system, with an improvement ranging from +20 % to +200 % compared to the other two topologies. On the other hand, the differences in terms of fuel economy are considered not relevant compared to the differences in durability
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