39 research outputs found
La tutela degli interessi collettivi nel diritto dell'Unione europea
No full textAs a result of some scandals (such as that of Dieselgate), collective actions have recently returned to the fore. While these mechanisms are particularly common in the United States, the European Union has always been quite dubious about the adoption of a comprehensive regulation on the matter. In recent times, however, as a result of the Commission's initiative, they have come back into vogue. In particular, the Commission presented a proposal of a directive on the protection of collective consumer interests in April 2018. The legislative procedure has gone ahead and it is now nearing its conclusion. In this context it is appropriate to evaluate, both the legitimacy of the action of the European political institutions, with regard to the division of competences in procedural matters, and the need for the same, in the light of certain provisions of the Charter of Fundamental Rights of the European Union. In particular, according to the author, an action by European institutions is necessary with reference to articles 37 and 38 of the Charter, concerning, respectively, the protection of the environment and consumers. In fact, in the absence of specific instruments for the protection of collective interests, the rights of these two categories would remain devoid of effective judicial protection, in sharp contrast with Section 47 of the same regulatory instrument. In this context, the author examines the current state of European legislation with reference to access to justice in environmental issues and the judicial protection of consumer rights
Experimental investigation into an ORC-based low-grade energy recovery system equipped with sliding-vane expander using hot oil from an air compressor as thermal source
No full textCompressed air production is an energy-intensive sector, thus compressor manufacturers are constantly looking for enhancing the efficiency, by acting on several technological aspects. In an air compressor, about 80-90% of the input electric power used is wasted into the environment through the oil circuit, continuously cooled by ambient air blown via a fan. An interesting way to optimize the overall system efficiency is to exploit this waste heat to produce electrical power. Organic Rankine Cycles (ORCs) are a suitable solution for recovering energy from low-grade heat source. In this paper, an experimental analysis of two low-grade ORC-based recovery systems is presented. The thermal source is the hot lubricant of a mid-size air compressor, while the thermal sink is tap water. The first system is tested in a simple cycle configuration while the second in a recuperative one. An extensive experimental campaign is carried out on a test bench composed by sliding-vane expander, pump and plate heat exchangers. The expander differs in terms of geometry and aspect ratio between the two cycles. R236fa is used as working fluid in both the systems. The expander operating conditions are deeply investigated by using piezoelectric pressure transducers to determine the expansion indicated diagram and the expander mechanical efficiency. Experimental results show that the recuperative cycle has a better performance, in terms of cycle efficiency and expander mechanical efficiency, compared with the simple cycle. For this configuration, two off-design conditions are investigated, acting on the pump rotational speed. Finally, an exergy analysis is conducted, in order to evaluate the irreversible losses produced by each component
An intracooling system for a novel two-stage sliding-vane air compressor
No full textLube-oil injection is used in positive-displacement compressors and, among them, in sliding-vane machines to guarantee the correct lubrication of the moving parts and as sealing to prevent air leakage. Furthermore, lube-oil injection allows to exploit lubricant also as thermal ballast with a great thermal capacity to minimize the temperature increase during the compression. This study presents the design of a two-stage sliding-vane rotary compressor in which the air cooling is operated by high-pressure cold oil injection into a connection duct between the two stages. The heat exchange between the atomized oil jet and the air results in a decrease of the air temperature before the second stage, improving the overall system efficiency. This cooling system is named here intracooling, as opposed to intercooling. The oil injection is realized via pressure-swirl nozzles, both within the compressors and inside the intracooling duct. The design of the two-stage sliding-vane compressor is accomplished by way of a lumped parameter model. The model predicts an input power reduction as large as 10% for intercooled and intracooled two-stage compressors, the latter being slightly better, with respect to a conventional single-stage compressor for compressed air applications. An experimental campaign is conducted on a first prototype that comprises the low-pressure compressor and the intracooling duct, indicating that a significant temperature reduction is achieved in the duct
Modeling And Testing The Thermal Effect Of Lubricating Oil Sprayed In Sliding-Vane Air Compressors Using Pressure-Swirl Nozzles
No full textA number of studies report the benefit of proper oil spraying in positive-displacement compressors. This work presents a thermodynamic model for simulating sliding-vane air compressors that employ an injection system for the lubricating oil based on both plain orifices and pressure-swirl nozzles to exploit the thermal effect of sprayed oil inside the compression chambers. An experimental campaign on a large-size compressor is conducted measuring, among all, the pressure within a chamber. This measurement is used to validate the model. Oil droplet diameters depend strongly on the injection technology, nozzles generating a finer atomization than orifices, as well as the differential pressure. In any case, the proper positioning of the nozzles allows for an effective heat transfer from the air to the oil
Experimental investigation on materials and lubricants for sliding-vane air compressors
No full textAbstract. Positive-displacement compressors and, among them, sliding-vane rotary machines are widely used in the compressed air sector. As in many other industrial fields, the efficient utilization of energy has become a major goal also in this sector. The aim of the present activity is the experimental investigation on the influence of two vanes materials (cast iron and aluminium with anodized surface) and of four commercial lubricants (characterized by different formulations and additives concentrations) on the performance of a mid-capacity sliding-vane rotary compressor in a number of operating pressures. The performance is identified by both the volume flow rate and the absorbed mechanical power, evaluated according to the international standard ISO 5167 and ISO 1217. The campaign indicates that the considered lubricants do not affect appreciably the volumetric flow rate. On the other hand, the specific lubricants determine a variation of about 1% of the mechanical power for both materials, while the specific material a variation between 0.9% and 2.6%. The best performance is achieved by aluminium vanes and a synthetic poly-α-olefin lubricant
Il Recovery Fund
No full textThe Next Generation EU (also called Recovery Fund for its function of restructuring the economy of the member States, after the COVID-19 pandemic) is a plan with which the European Union aims to raise funds on the market through the issue of bonds and, subsequently, to disburse sums of money, including non-repayable funds, for the realization of projects of common European interest. With this plan, the EU intends to finance the so-called green transition, bridge the digital divide and, in addition, support the structural reforms necessary for each member State. The program is very ambitious and marks a turning point in the European Union’s approach to managing economic crises, in the sense that, instead of the so-called ‘austerity’, the supranational legislator prefers to finance investments capable of supporting growth and industrial reconversion. The paper analyzes the conclusions of the extraordinary meeting of the European Council in July and the main draft acts published by the European Commission. The author notes that the program presents certain provisions which, at first glance, may appear incompatible with the Treaty, such as the power of the Commission to issue bonds and the incidence of the no bail-out clause on the legitimacy of non-repayable aids. However, these doubts can be resolved in the light of the correct reading of the provisions of the Treaty on the Functioning of the European Union. The problem is that the Next Generation EU plan ends up restricting the already limited room for maneuver of national parliaments in defining economic policies, so it does not seem really lawful in the light of the democratic principle enshrined in Article 10 TEU
Intelligenza artificiale e dati personali
No full textThe European Commission, on April 21, 2021, adopted a legislative proposal of a regulation on artificial intelligence.
This proposal was formulated after a long preparatory work, in which all the political institutions of the EU have been involved.
The proposal does not intend to interfere with the regulatory framework for the protection of personal data (regulation 2016/679).
However, there appears to be some overlap between the two sources of EU law. These overlaps concern the principle of consent, the so called minimization, the pseudoanonymization, the improper use of involuntary discriminatory biases and the right to the explanation of the outcome of a specific system of artificial intelligence.
The author tries to overcome the overlaps and the disharmonies due to the cumulative application of the two sources of EU law (reg. 2016/679 and the future regulation on AI), but it would be better for the European legislator to clarify how to solve the difficulties discending from the application of the GDPR to artificial intelligence systems
Modeling and Experimental Activities on a Small-scale Sliding Vane Pump for ORC-based Waste heat Recovery Applications
No full textPumping work in energy recovery units based on Organic Rankine Cycles (ORC) can severely affect the net power output
recovered. Nevertheless, in recent years scientific and industrial communities mainly focused on expanders’ development. In
order to address this lack of know-how and equipment, the current paper presents the development of a positive displacement
ORC pump based on the sliding vane rotary technology. The machine was installed in a power unit for low-medium grade
thermal energy recovery that operated with oil at 70-120°C as upper thermal source and tap water as lower one. Working fluid
was R236fa while cycle pressure ratio ranged from 2.8 to 3.7. The ORC pump was also tested at different revolution speeds such
that mass flow rate varied between 0.05 kg/s and 0.12 kg/s. These experimental data were further used to validate a
comprehensive one-dimensional model that takes into account fluid dynamic filling and emptying processes, closed vane
transformation and leakages at blade tip, rotor slots and end walls clearances. Viscous and dry friction phenomena occurring
between components in relative motion were additionally considered. A full operating map of the sliding vane pump was
eventually retrieved to explore multiple off-design operating conditions. The parametric and modular structure of the model will
act as a design platform to outline enhanced ORC sliding vane pump prototypes
La proposta della Commissione europea di adozione del “Digital Markets Act”
No full textI mercati digitali presentano caratteristiche molto peculiari, che ne hanno determinato una struttura fortemente oligopolistica. Questo assetto ha, fino a questo momento, prodotto diverse conseguenze dannose, sia sul funzionamento del mercato che sullo sviluppo di nuove imprese e nuovi prodotti. In questo contesto, diversi Stati hanno cercato di contrastare il fenomeno attraverso l’intervento delle autorità antitrust. Tuttavia, al momento, i tentativi sembrano non aver prodotto gli effetti sperati. L’approccio ora tentato dalla Commissione europea, che sta cercando di introdurre una specifica regolamentazione ex ante delle piattaforme online, fa sperare in una parziale soluzione del problema. La proposta non appare, tuttavia, molto chiara su una questione cruciale, che è il rapporto della stessa con la normativa antitrust. A parere dell’Autore, il Digital Markets Act deve essere considerato come una fonte di diritto complementare, il che significa che gli obblighi previsti al suo interno devono sommarsi agli obblighi previsti dagli artt. 101 e 102 TFUE.Digital markets present very peculiar characteristics, which have determined a strongly oligopolistic structure of the market. This structure has produced several harmful consequences, both on the functioning of the market and on the development of new businesses and new products. In this context, several States have tried to tackle the phenomenon through the intervention of the antitrust authorities. However, at the moment, the attempts do not seem to have produced the desired effects. In this context, the approach now attempted by the European Commission, which is trying to introduce specific ex ante regulation of online platforms, gives hope for a partial solution to the problem. The proposal is not very clear on a crucial matter, which is the relationship between the proposal itself and the antitrust rules. According to the opinion of the Author, the Digital Markets Act must be regarded as a complementary source of law, which means that the obligations provided within should add up to the obligations provided for by Articles 101 and 102 TFEU
