1,721,519 research outputs found
Advanced energy management strategies for Renewable Energy Communities
Full text linkL'abstract è presente nell'allegato / the abstract is in the attachmen
Magnetic field sensors suitable for high temperature and vacuum operations and for remote handling in harsh environment
Full text linkIn the context of the alternative technologies for energy production, nuclear fusion is the most promising in order to reduce global dependence on fossil fuels such as oil and coal. Fusion research aims at developing a new energy source in the medium term and it should be engineered in the second half of this century, coming alongside the current technologies.
Research on tokamak such as JET and ITER (DEMO in the future), based on the plasma confinement through the use of magnetic fields, is at present the most promising and should provide important results in the coming two decades.
In this context magnetic diagnostics are of great importance, providing key information on the confinement of high temperature plasma and allowing an active control on the position and shape of the plasma itself.
This work deals with the design, development and production of magnetic sensors, suitable for operation in hostile environments such as the ITER vacuum vessel. These sensors are designed to withstand high temperatures and intense neutron irradiation and have to be installed behind the plasma first wall, in contact to the vessel. These sensors have been built in order to measure magnetic fields having a frequency between 50Hz and 10 kHz.
This work is structured as follows:
• Chapter 1 provides an overview of the energy problem and describes the theoretical basis of nuclear fusion
• Chapter 2 introduces the importance of the magnetic diagnostic in the thermonuclear fusion research and lists the sensors used in existing machines (JET, RFX-mod, JT60), with a focus on the issues related to ITER
• Chapter 3 describes the development and construction of a new type of sensor built using the LTCC technology. This chapter lists the tests and the micrographic analysis carried out upon these new sensors
• Chapter 4 describes the development and construction of a new sensor formed by a copper wire with fiberglass insulation (called POZh) wound on a metallic reel
• Chapter 5 describes the design of the platform necessary to support these sensors (LTCC/POZh) within the ITER vacuum vesselNell’ambito delle tecnologie alternative per la produzione di energia la fusione termonucleare controllata appare la più promettente allo scopo di diminuire la dipendenza mondiale dai combustibili fossili quali il petrolio e il carbone. La ricerca sulla fusione mira allo sviluppo di una nuova fonte energetica nel medio termine e dovrebbe trovare ingegnerizzazione nella seconda metà di questo secolo, affiancando le attuali tecnologie.
La ricerca sui tokamak quali JET e ITER e il futuro DEMO, basata sul confinamento del plasma attraverso l’utilizzo di campi magnetici, appare allo stato attuale la più promettente e dovrebbe fornire risultati importanti già nei prossimi due decenni.
Nell’ambito della fusione termonucleare controllata grande importanza rivestono le diagnostiche magnetiche, che forniscono informazioni fondamentali sullo stato del plasma e permettono un controllo attivo sulla posizione e la forma dello stesso.
Questa tesi si occupa dell’ideazione, sviluppo e produzione di due nuove tipologie di sensori magnetici, adatti al funzionamento in ambienti ostili quali l’interno della camera da vuoto (vessel) di ITER. Tali sensori sono stati ideati per resistere ad alte temperature e ad intensi bombardamenti neutronici e dovranno essere installati dietro la prima parete del vessel, a contatto dello stesso. Si tratta di sensori per campi magnetici aventi una frequenza compresa tra 0.001Hz e 10kHz.
La tesi è così strutturata:
• Il capitolo 1 fornisce una visione di massima sul problema energetico e descrive i rudimenti teorici della fusione nucleare
• Il capitolo 2 introduce il problema delle diagnostiche magnetiche elencando i tipi di sensori utilizzati in macchine esistenti (JET, RFX-mod, JT60), con un approfondimento delle problematiche relative ad ITER
• Il capitolo 3 descrive lo sviluppo e la produzione di diversi set di sensori costruiti utilizzando la tecnologia LTCC. Tale capitolo elenca i test e le analisi micrografiche effettuate
• Il capitolo 4 descrive lo sviluppo e la costruzione di una serie di sensori costruiti mediante la tecnologia del cavo avvolto usando cavi in rame con isolamento in fibra di vetro denominati POZh
• Il capitolo 5 descrive il progetto di una struttura necessaria al supporto di tali sensori (LTCC/POZh) all’interno del vessel di ITE
Aflatoxins Absorption and Excretion Dynamics in Dairy Cows: Technical Strategies to Reduce Metabolites Carry over in Milk
No full textLe aflatossine sono potenti sostanze cancerogene presenti in natura. L'aflatossina b1 viene poco degradata nel rumine ed è escreta nel latte come aflatossina M1 con un carry over del 1-3%. Nel presente lavoro è stata studiata l'apparizione delle aflatossine nel sangue conseguente all'ingestione orale di un bolo contaminato per verificare come queste tossine sono assorbite nel tratto digestivo delle vacche da latte. La comparsa nel plasma e nel latte attraverso una mucosa tipicamente non di assorbimento per determinare il possibile meccanismo che regola l'assorbimento delle aflatossine è stato un ulteriore oggetto di studio. Un'altra prova è stata effettuata con vacche da latte per studiare il carry-over dell'aflatossina B1 nel latte in relazione al livello produttivo e alle cellule somatiche, come indicatore di processi infiammatori nella mammella. La capacità sequestrante di diversi tipi di adsorbenti è stata comparata in prove in vitro condotte in differenti condizioni sperimentali. Anche il comportamento del complesso aflattosina-adsorbente nel tratto digestivo di vacche in lattazione è stato studiato in vivo per mezzo della misurazione della presenza di aflatossina M1 nel latte. Una prova in vivo è stata effettuata per verificare l'effetto che la pellettatura o la semplice miscelazione di adsorbenti nei mangimi può avere nel migliorare l'efficienza di sequestro.Aflatoxins are the most potent natural carcinogenic compound present in nature. Aflatoxin B1 is poorly degraded in the rumen and is excreted in milk as aflatoxin M1 with a carry-over rate of 1-3%. The present work investigated rate and schedule of aflatoxins plasma appearance following an oral contaminated bolus to verify how these toxins are absorbed in the gastro-intestinal tract of dairy cows. Aflatoxins plasma and milk appearances were also investigated using a non-absorbing mucosa to understand the possible aflatoxins absorption mechanism through mucous membranes. A trial was carried out in lactating dairy cows to study the carry over of ingested aflatoxin B1 in milk as aflatoxin M1 in relation to milk yield and somatic cells count, the latter as indicator of udder inflammatory processes. sequestering capacity of different kinds of mycotoxins sequestering agents were compared in vitro trial carried out at different experimental conditions. The behaviour of the aflatoxins-adsorbents complexes through digestive tract of lactating dairy cows were also investigated in vivo by measuring appearance of aflatoxin M1 into milk. An in vivo trial was conducted to verify if effect of pelletizing or simply mixing processes is useful to improve mycotoxins sequestering agents efficacy in dairy cow nutrition
The role of advanced energy management strategies to operate flexibility sources in Renewable Energy Communities
Full text linkRenewable Energy Communities (REC) can largely contribute to building decarbonization targets and provide flexibility through the adoption of advanced control strategies of the energy systems. This work investigates how the role of flexibility sources will be impacted by shifting towards advanced control strategies under a high penetration of variable Renewable Energy Sources, in the following years. A large residential area with diverse energy systems, building envelope configurations, and energy demand patterns is modeled with the simulation environment RECsim, a virtual testbed for the implementation of energy management strategies in REC. Photovoltaic (PV) panels, Battery Energy Storage and Thermal Energy Storage (TES) of different sizes for each household provide a realistic description of a REC which includes both consumers and prosumers. This study explores a scenario in which advanced controllers based on Deep Reinforcement Learning (DRL) replace existing Rule-Based Controllers in building energy systems across a significant number of buildings. These control policies are simulated under three different scenarios that consider consumers with different pricing schemes and TES penetration. Efficient control strategies, have demonstrated significant potential, regardless of the presence of thermal storage and ToU pricing schemes, in reducing energy demand by 12.6%, cutting energy costs by 20.8%, and enhancing self-sufficiency and self-consumption, with minimal impact on Shared Energy. Implementing a flat tariff scheme under DRL enables consumers to increase their energy demand during periods of PV generation, which is particularly advantageous in a REC. Also, this approach lowers overall energy demand by 12.6% and boosts self-sufficiency, and it also decreases electricity exports from the REC to the grid by 18.2% compared to a ToU tariff scheme. When using ToU tariffs, thermal storage can be used to achieve cost savings, but total Shared Energy decreases, as do self-sufficiency and self-consumption of the REC. The results indicate that in a REC with high variable renewable energy and decentralized control, consumers using TES and ToU tariffs with peak prices during high irradiance periods may not be beneficial for the grid compliance. In conclusion, the coupling between DRL and thermal storage should be supported by more innovative pricing schemes for RECs and/or coordinated energy management, although it requires advanced communication and monitoring infrastructure
Multiple sclerosis patients and immunomodulation therapies: the potential role of new MRI techniques to assess responders versus non-responders
No full textDisease-modifying drugs (DMD) are effective in reducing relapses and magnetic resonance imaging (MRI) lesions in multiple sclerosis (MS). Nevertheless, individual treatment responses are variable, and accurate and reliable methods to identify DMD responsiveness have not been validated. Although extremely relevant in the study and management of MS, MRI data have not been systematically tested to answer this question yet. Here we present non-conventional MRI data, including magnetisation transfer imaging (MTI), diffusion-weighted imaging (DWI) and proton magnetic resonance spectroscopy ((HMRS)-H-1). As these techniques are more sensitive to microstructural tissue changes and more specific for the heterogeneous pathological substrates of MS lesions, we anticipate their potential role for detecting relevant changes of tissue pathology during treatment of MS patients and, consequently, for a better definition of response status to therapy
Microencapsulated sodium selenite supplementation in dairy cows: effects on selenium status
No full textThe objective of this study was to compare the efficiency of transfer of
selenium (Se) to plasma and milk from inorganic sodium selenite, either
free or microencapsulated, and from selenized yeast in dairy cows. The
study consisted of an in situ-nylon bags incubation, and in an in vivo
experiment to compare the Se status of cows supplemented with either
sodium selenite, microencapsulated sodium selenite, or Se yeast. Thirty
dairy cows, divided in five groups, were fed the following diets: the
control group (CTR) received a total mixed ration supplemented with
sodium selenite in order to have 0.3 mg/kg DM of total Se; 0.3M and 0.5M
groups received the same control diet supplemented with lipid
microencapsulated sodium selenite to provide 0.3 and 0.5 mg/kg DM of
total Se, respectively; 0.3Y and 0.5Y groups received selenized yeast to
provide 0.3 and 0.5 mg/kg of total Se, respectively. Cows were fed the
supplements for 56 days during which milk, blood, and fecal samples were
collected weekly to conduct analysis of Se and glutathione peroxidase
(GSH-px) activity. Se concentration in the nylon bags was assessed to
72\%, 64\%, and 40\% of the initial value (time 0) after 4, 8, and 24 h
of incubation, respectively. In vivo, cows supplemented with 0.3 mg/kg
of microencapsulated Se had higher milk Se concentration compared to
CTR. The increment was more pronounced at the highest inclusion rate
(0.5 mg/kg, 0.5M group). GSH-px activity was not significantly affected
by treatments. The results indicate that lipid microencapsulation has
the potential to protect nutrients from complete rumen reduction and
that Se from microencapsulated selenite is incorporated in milk more
efficiently than the free form. Microencapsulated sodium selenite was
shown to be comparable to Se-yeast in terms of availability and
incorporation in milk when fed at 0.3 mg/kg DM, whereas the inclusion in
the diet at 0.5 mg/kg DM resulted in higher plasma and milk
concentrations than selenized yeast
An input-output clustering approach to the synthesis of ANFIS networks
No full textA useful neural network paradigm for the solution of function approximation problems is represented by adaptive neuro-fuzzy inference systems (ANFIS). Data driven procedures for the synthesis of ANFIS networks are typically based on clustering a training set of numerical samples of the unknown function to be approximated. Some serious drawbacks often affect the clustering algorithms adopted in this context, according to the particular data space where they are applied. To overcome such problems, we propose a new ANFIS synthesis procedure where clustering is applied in the joint input-output data space. Using this approach, it is possible to determine the consequent part of Sugeno first-order rules and therefore the hyperplanes characterizing the local structure of the function to be approximated. Successivelyl the fuzzy antecedent part of each rule is determined using a particular fuzzy min-max classifier, which is based on the adaptive resolution mechanism. The generalization capability of the resulting ANFIS architecture is optimized using a constructive procedure for the automatic determination of the optimal number of rules. Simulation tests and comparisons with respect to other neuro-fuzzy techniques are discussed in the paper, in order to assess the efficiency of the proposed approach
Effect of parity on the feeding behaviour of dairy cows
No full textThe trial was carried out on Italian Friesian cows raised in an experimental free stall barn. The cows were fed
once daily (TMR administered at 07:00) and milked twice daily (at 03:00 and at 15:00). During the trial 9 check
points, throughout the seasons, were planned to observe feeding behaviour of cows raised in a pen equipped
with 24 (1 per cow) feeding stations (Bio Control A/S). At each check point were continuously observed (per 3
days) 18-20 lactating cows for feeding behaviour parameters; finally were obtained data of 46 cows, 18 primiparous
(PR) and 28 pluriparous (PL), between 50 and 250 DIM. Indexes of feeding behaviour, collected and
automatically registered by the system, were number of visits, intake per visit and duration of visit. Indexes
of feeding behaviour calculated were number of meals (considering the same meal when the interval between
the visits was lower than 20 minutes), intake per meal, duration of meal and consumption rate. These indexes
have been studied during the 24 h, in daytime (from 07:00 to 19:00) and in night time (from 19:00 to 07:00).
At each check point was also recorded the individual milk yield, the TMR composition and its DM content.
Primiparous had a slightly lower milk yield and a lower average DMI (19.25±2.89 vs. 20.77±3.24 kg DM/d, in
PR and PL respectively). In PR, despite lower DMI, a higher number of meals in the 24 h (7.72±2.13 vs.
6.72±1.83, in PR and PL respectively) with a lower DMI per meal (2.67±0.79 vs. 3.27±0.81 kg DM/meal, in PR
and PL respectively) and a lower consumption rate (96±20 vs. 118±26 g of DM/min, in PR and PL respectively)
was observed. In addition a higher number of visits per day and visit per meal was observed in PR. DMI
during diurnal hours was 74.61±11.69% of daily DMI in PR and 75.09±11.54% in PL, and it was concentrated
after feeding distribution (at 07:00) and after evening milking (15:00). In conclusions our data show that primiparous
cows need more time to chew feeds, and this should be considered important in creating feeding strategies
that aim to best feed activity and stimulate intake, particularly at the beginning of lactation and when
PR are raised with PL
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