Analisi fisico-tecnica rivolta allo sviluppo dei motori a combustione interna alimentati ad idrogeno

Il presente lavoro si compone di due parti: 1)Analisi critica dello sviluppo degli H2ICEs e delle diverse soluzioni tecniche presenti in letteratura 2)Sviluppo di un modello fenomenologico 0D in grado di simulare il diagramma delle pressioni e fornire utili informazioni per individuare le soluzioni più corrette nella progettazione di un H2ICE

(Machine) Learning from the COVID-19 Lockdown about Electricity Market Performance with a Large Share of Renewables

The negative demand shock due to the COVID-19 lockdown has reduced net demand for electricity -- system demand less amount of energy produced by intermittent renewables, hydroelectric units, and net imports -- that must be served by controllable generation units. Under normal demand conditions, introducing additional renewable generation capacity reduces net demand. Consequently, the lockdown can provide insights about electricity market performance with a large share of renewables. We find that although the lockdown reduced average day-ahead prices in Italy by 45%, re-dispatch costs increased by 73%, both relative to the average of the same magnitude for the same period in previous years. We estimate a deep-learning model using data from 2017--2019 and find that predicted re-dispatch costs during the lockdown period are only 26% higher than the same period in previous years. We argue that the difference between actual and predicted lockdown period re-dispatch costs is the result of increased opportunities for suppliers with controllable units to exercise market power in the re-dispatch market in these persistently low net demand conditions. Our results imply that without grid investments and other technologies to manage low net demand conditions, an increased share of intermittent renewables is likely to increase costs of maintaining a reliable grid

Replacement Reserve for the Italian Power System and Electricity Market

Over the last years, power systems around the globe experienced deep changes in their operation, mainly induced by the widespread of Intermittent Renewable Energy Sources (IRES). These changes involved a review of market and operational rules, in the direction of a stronger integration. At European level, this integration is in progress, driven by the new European guidelines and network codes, which deal with multiple issues, from market design to operational security. In this framework, the project TERRE (Trans European Replacement Reserve Exchange) is aimed at the realization of a European central platform, called LIBRA, for the exchange of balancing resources and, in particular, for the activation of the procured Replacement Reserve (RR) resources. The Italian Transmission System Operator (TSO), TERNA, is a participant of the project and it is testing new methodologies for the sizing of RR and its required activation throughout the TERRE process. The aim of the new methodologies is to find areas of potential improvement in the sizing of RR requirements and activation, which open up the possibility for a reduction of the procurement cost, without endangering the security of the power system. This paper describes a new RR sizing methodology, proposed by TERNA, which is based on a persistence method, showing its results on real data and highlighting key advantages and potential limitations of this approach. In order to overcome these limitations, a literature review on alternative approaches has been carried out, identifying nowcasting techniques as a relevant alternative for the very short term forecast horizon. These one could be further investigated and tested in the future, using the proposed persistence method as a benchmark

Posttransplantation chronic renal damage in nonrenal transplant recipients

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Model-Based Identification of Alternative Bidding Zones: Applications of Clustering Algorithms with Topology Constraints

The definition of bidding zones is a relevant question for electricity markets. The bidding zones can be identified starting from information on the nodal prices and network topology, considering the operational conditions that may lead to congestion of the transmission lines. A well-designed bidding zone configuration is a key milestone for an efficient market design and a secure power system operation, being the basis for capacity allocation and congestion management processes, as acknowledged in the relevant European regulation. Alternative bidding zone configurations can be identified in a process assisted by the application of clustering methods, which use a predefined set of features, objectives and constraints to determine the partitioning of the network nodes into groups. These groups are then analysed and validated to become candidate bidding zones. The content of the manuscript can be summarized as follows: (1) A novel probabilistic multi-scenario methodology was adopted. The approach needs the analysis of features that are computed considering a set of scenarios defined from solutions in normal operation and in planned maintenance cases. The weights of the scenarios are indicated by TSOs on the basis of the expected frequency of occurrence; (2) The relevant features considered are the Locational Marginal Prices (LMPs) and the Power Transfer Distribution Factors (PTDFs); (3) An innovative computation procedure based on clustering algorithms was developed to group nodes of the transmission electrical network into bidding zones considering topological constraints. Several settings and clustering algorithms were tested in order to evaluate the robustness of the identified solution

Amniotic mesenchymal cells from pre-eclamptic placentae maintain immunomodulatory features as healthy controls

Pre-eclampsia (PE) is one of the most severe syndromes in human pregnancy, and the underlying mechanisms of PE have yet to be determined. Pre-eclampsia is characterized by the alteration of the immune system's activation status, an increase in inflammatory Th1/Th17/APC cells, and a decrease in Th2/Treg subsets/cytokines. Moreover, inflammatory infiltrates have been detected in the amniotic membranes of pre-eclamptic placentae, and to this date limited data are available regarding the role of amniotic membrane cells in PE. Interestingly, we and others have previously shown that human amniotic mesenchymal stromal cells (hAMSC) possess anti-inflammatory properties towards almost all immune cells described to be altered in PE. In this study we investigated whether the immunomodulatory properties of hAMSC were altered in PE. We performed a comprehensive study of cell phenotype and investigated the in vitro immunomodulatory properties of hAMSC isolated from pre-eclamptic pregnancies (PE-hAMSC), comparing them to hAMSC from normal pregnancies (N-hAMSC). We demonstrate that PE-hAMSC inhibit CD4/CD8 T-cell proliferation, suppress Th1/Th2/Th17 polarization, induce Treg and block dendritic cells and M1 differentiation switching them to M2 cells. Notably, PE-hAMSC generated a more prominent induction of Treg and higher suppression of interferon-\u3b3 when compared to N-hAMSC, and this was associated with higher transforming growth factor-\u3b21 secretion and PD-L2/PD-L1 expression in PE-hAMSC. In conclusion, for the first time we demonstrate that there is no intrinsic impairment of the immunomodulatory features of PE-hAMSC. Our results suggest that amniotic mesenchymal stromal cells do not contribute to the disease, but conversely, could participate in offsetting the inflammatory environment which characterizes PE

Evaluation of Cost-at-Risk related to the procurement of resources in the ancillary services market. The case of the Italian electricity market

Measuring the risk exposure of TSOs on the dispatching market is a crucial task for the correct management of liberalized electricity markets. To fill a gap in the literature, the notion of Cost-at-Risk (CaR) is defined in the context of the dispatching market. Moreover, we propose a set of semi-parametric and non-parametric models for the estimation of the Cost at Risk (CaR) for the Italian TSO (Terna) and evaluate the corresponding out-of-sample forecasting performance. The empirical analysis relies on a rich hourly dataset provided by Terna, including several costs’ drivers. The results, in terms of 1-day and 30-day ahead predictions, suggest that the model with the globally best performance is the semi-parametric GAM-GARCH model

Human powered press for producing straw bales for use in construction during post-emergency conditions

The straw bale construction technique is considered one of the most appropriate for the improvement of housing conditions in developing countries and for the reconstruction in post-emergency situations. In this environment, no electricity or other energy sources are available; for this reason, straw bales have to be produced by means of a human powered press. This paper presents the designing process of a manual press, that is a key tool for the objectives introduced above. Following definition of the machine architecture and the actuating mechanism (slider-crank), a design method based on energy considerations is introduced. Given the mechanical properties of straw, described by a simplified linear model, and the maximum work that a human operator can do, applying the designing method, it was possible to obtain the main functional parameters of the machine, such as the pressing piston stroke, and the length both of the connecting rod and of the crank. The method was experimentally validated and a prototype assembled and used for the production of infill bales in the construction of a warehouse in Hait

Human powered press for producing straw bales for use in construction during post-emergency conditions

The straw bale construction technique is considered one of the most appropriate for the improvement of housing conditions in developing countries and for the reconstruction in post-emergency situations. In this environment, no electricity or other energy sources are available; for this reason, straw bales have to be produced by means of a human powered press. This paper presents the designing process of a manual press, that is a key tool for the objectives introduced above. Following definition of the machine architecture and the actuating mechanism (slider-crank), a design method based on energy considerations is introduced. Given the mechanical properties of straw, described by a simplified linear model, and the maximum work that a human operator can do, applying the designing method, it was possible to obtain the main functional parameters of the machine, such as the pressing piston stroke, and the length both of the connecting rod and of the crank. The method was experimentally validated and a prototype assembled and used for the production of infill bales in the construction of a warehouse in Hait

A SystemC-based Simulator for Design Space Exploration of Smart Wireless Systems

Smart wireless techniques are at the core of many today's telecommunication and networked embedded systems where performance are enhanced by intertwining radio frequency (RF) and digital aspects. Therefore their design requires to focus on both domains. Traditional approaches for their simulation rely either on different domain-specific tools or on analog-mixed-signal modeling languages. In the former case, the simulation of the whole platform in the same run is not possible while in the latter case, simulation performance are limited by the computationally most intensive domain (usually RF). We present an extension of the SystemC Network Simulation Library that allows to simulate antenna details and node position together with digital hardware and software. The validation on a real wearable system shows that the proposed simulation approach achieves a good trade-off between accuracy and speed thus allowing fast exploration of various configurations in the early phase of the design flow without recurring to the expensive and time-consuming creation of physical prototypes