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SOFC composite electrodes of yttria-stabilized zirconia (YSZ) and either LaNi(0.6)GFe(0.4)O(3) (LNF) or La0.91Sr0.09Ni0.6Fe0.4O3 (LSNF) were prepared by infiltration to a loading of 40 wt% of the perovskite into Porous YSZ using aqueous solutions of the nitrate salts. XRD measurements indicated that the perovskite structures were formed following calcination at 850 degrees C, at which temperature the LNF and LSNF form small particles that coat the YSZ pores. Heating to 1100 degrees C causes the particles to form a dense film over the YSZ but caused no solid-state reaction. Calcination of an LNF-YSZ composite to 1200 degrees C led to an expansion of the LNF lattice, suggesting introduction of Zr(IV) into the perovskite; further heating to 1300 degrees C caused the formation of La2Zr2O7. For 850 degrees C calcination, the electrode performance of both LNF-YSZ and LSNF-YSZ composites was similar to that reported for composites of YSZ and La0.8Sr0.2FeO3 (LSF), with a current-independent impedance of approximately 0.1 Omega cm(2) at 700 degrees C in air. For 1100 degrees C calcination, both LNF-YSZ and LSNF-YSZ composites exhibited impedances that decreased strongly under both anodic and cathodic polarization. The implications of these results for preparing electrodes based on LNF and LSNF are discussed.

Abstract In this work, the Petri-net modelling approach applied to the control system design of the Advanced Lead Fast Reactor European Demonstrator (ALFRED) is presented, paying particular attention to the startup procedure. The reactor startup is the operational transient in which all the systems of the plant are brought from the cold shutdown condition to the full power mode, close to load-frequency control. In this phase, the several control actions to be taken need to be properly coordinated. To this end, the operational sequence which constitutes the reactor startup procedure has been described by adopting the Petri-nets approach, i.e., a useful formalism for the modelling and the analysis of Discrete Event Systems. Thanks to this quantitative representation, it is possible to easily derive the corresponding control scheme. In addition, the Petri-nets approach has been also exploited for the two-level control system architecture, namely a master system coordinates the operation of the plant by sending suitable signals to the slave system, in which feedback controllers are implemented. As a major outcome of this work, the procedure for the reactor startup and the transition to the full power mode has been simulated in order to assess the control system performance.

AbstractThe traceability of measurements performed to gauge information about the operation of electrical power systems under nonsinusoidal conditions is an important and live issue, usually neglected by the technical Standards. A generalized definition of the “composite error” is proposed in this paper as a meaningful index for the metrological characterization of voltage and current transducers in steady‐state nonsinusoidal conditions. In this connection, the relationship among the composite error, the classical ratio and phase‐angle errors and other parameters characterizing the waveforms of the transduced quantities are pointed out. Finally, problems involved in the measurement of the composite error in steady‐state distorted conditions are dealt with and the results of some experimental work are presented.

RFID tags will really become smart objects of the Internet of Things (IoT) if they will be able to exploit the passive nature of the communication also for exchanging data with any other networked devices in the Internet. To this aim, an adaptation layer, named 6lo-RFID, has been specifically designed to run IPv6 over the RFID link technology. In this paper we draw the design principles for the development of a fully passive, IPv6-compliant, and energy-efficient 6lo-RFID tag platform. In particular, we discuss the block's design of an RF energy harvester and evaluate the simulated performance of a fully-passive 6lo-RFID tag when GET/PUT CoAP methods are used to execute operations on the tag memory.

The official involvement of Italy in Antarctic research dates back to 1985, when Mario Zucchelli Station (the former Terra Nova Bay Station) was established in Terra Nova Bay. Italy joined the Antarctic Treaty in 1987. This article is an overview of the wide-ranging research in marine biology performed in the last three decades by the author's team in the Ross Sea. Fundamental questions have been addressed, related to cold adaptations--with special attention to the molecular bases--evolved by marine organisms along with progressive cooling in this geographic area, also analysed in comparison with other important areas, such as the Peninsula, the Weddell Sea, the sub-Antarctic and the Arctic. The basic stepping stone of this research was the integration of ecophysiology with molecular aspects, in the general framework of biodiversity, adaptation and evolution. Investigations have addressed a number of Ross Sea taxa, comprising fish, birds, urchins, whales, seals and bacteria. Its significance has special meaning in view of the control that Antarctica exerts on the world climate and ocean circulation, which has awakened great interest in the evolutionary biology of the organisms that live there.

Abstract The growing integration of renewable energy sources in the energy grid presents intermittency and negative pricing challenges, necessitating large-scale energy storage solutions. Pumped thermal energy storage (PTES) can address these issues by storing and delivering substantial energy whenever required. High-temperature heat pump development is crucial to deploying PTES for storing heat at sink temperatures that are well above the ambient temperature(>450 °C) to ensure a reasonable round-trip efficiency (RTE). Currently, however, it is not a technological possibility for heat pumps to achieve these temperatures even with the support of freely available heat (200 °C to 400 °C) as source temperatures. This study explores a potential layout of the TI-PTES system that exploits commercially available equipment by storing heat below the ambient temperature while still being able to utilize the freely available heat source (Solar, Waste heat, biomass, etc.) to support the overall RTE. The charging phase employs a well-established CO2-refrigeration cycle to accumulate energy below the ambient temperature in cold thermal storage. While the discharging phase runs a trans-critical CO2 power cycle between the freely available heat source and the cold thermal storage. Overall, offering a practically implementable model for the PTES system with market-available components. The study investigates the design of this innovative system presenting the relevance of different operating and machine parameters as well as the contribution of freely available heat sources to the overall performance. Finally, benchmarking the technology with other long-duration energy storages.

The introduction of the high-pressure fully electronic-controlled injection systems has opened a number of new possibilities to optimize diesel engine performance and to reduce pollutant emissions. However greater research efforts are required to meet future European emission legislation. The control of the combustion process, which determines to a large extent the amount of pollutant emissions, requires primarily an understanding of its physics and chemistry as well as the capability to modify one or more of the interdependent process parameters in a given direction. Since many parameters have to be considered, a combined experimental-numerical approach is required. In this context, the research group of the University of Rome "Tor Vergata", which has developed a multidimensional code for diesel engines simulation based on the KIVA 3V code, and the research group of the University of Perugia, which has built a laboratory for the characterization of diesel and SI injection systems and sprays, have been collaborating for many years. The implemented models in the multidimensional code enable full 3D computation of both gas and fuel spray dynamics to be made, including atomization, vaporization, autoignition and combustion. However, spray development, mixture preparation and combustion depend on the fuel injection system characteristics and actual operating conditions. Therefore, modelling of the fuel injection system is essential to correctly predict all those parameters involved in the fuel injection, which are still often considered as constant input data in 3D simulations. In this paper a 1D model, built in the AVL HYDSIM environment, of the CR injection system of the University of Perugia laboratory is presented and reliability of numerical results is tested through a comparison with experimental data. Then, 3D simulations of diesel spray development are performed coupling the 1D model of the injection system to the multi-dimensional code.

A two-step simulation methodology was applied for the computation of the injector nozzle internal flow and the spray evolution in diesel engine-like conditions. In the first step, the multiphase cavitating flow inside injector nozzle is calculated by means of unsteady CFD simulation on moving grids from needle opening to closure. A non-homogeneous Eulerian multi-fluid approach - with three phases i.e. liquid, vapor and air - has been applied. Afterward, in the second step, transient data of spatial distributions of velocity, turbulent kinetic energy, dissipation rate, void fraction and many other relevant properties at the nozzle exit were extracted and used for the subsequent Lagrangian spray calculation. A primary break-up model, which makes use of the transferred data, is used to initialize droplet properties within the hole area. The paper focuses on the analysis of the injection process comparing the effects different fuels - a standard diesel fuel and a pure biodiesel, methyl ester of soybean oil - in two types of nozzles, i.e. cavitating and non-cavitating. Biodiesel fuel is characterized by higher density, higher viscosity and lower vapor pressure, compared to diesel fuel. Extent of cavitation region was found to be strongly dependent on the nozzle shape, whereas not much affected by the fuel type. Detailed analyses of the injection processes are presented, including flow pattern development inside the nozzles. Simulations of the spray evolution are also discussed highlighting the differences between the use of fossil and biodiesel fuels in terms of spray penetration, atomization and spray angle. Simulations of spray evolutions, in non-evaporative conditions, highlighted that hole shape affects diesel penetration and angle. Biodiesel spray, instead, is less sensitive to hole shaping. SMD is larger for biodiesel, irrespectively of hole shape and injection pressure. Diesel fuel in non-cavitating nozzle provides higher penetration and lower spray angle.