Studio di lay-out alternativi per impianti termoelettrici a carbone con SCWO a zero emissioni di CO2 ed analisi di fattibilita' economica

La tesi è stata svolta presso il Dipartimento di Energetica dell’Università di Pisa, in collaborazione con il centro ENEL s.p.a – Generation and Energy Management di Pisa. Questo studio è partito dalla definizione di un impianto termoelettrico a carbone con combustione in acqua supercritica (SCWO), sviluppato in un precedente lavoro di tesi che si basava, a sua volta, su un’idea proposta da alcuni ricercatori del M.I.T. (Massachussets Institute of Technology). Gli obiettivi del lavoro sono stati lo studio di lay-out alternativi di impianti termoelettrici a carbone con SCWO e l’analisi di fattibilità economica al variare della potenza netta, per l’impianto con le migliori prestazioni. Lo studio delle nuove configurazioni di impianto è stato eseguito tramite la creazione di modelli in Aspen Plus. Solo il modello con recupero e ricircolo dell’eccesso stechiometrico di O2 ha dato prestazioni migliori (rendimento netto vicino al 29%, rispetto al 28% che si ottiene nella configurazione studiata nel precedente lavoro). Per questo lay-out è stato esaminato il comportamento in condizioni stazionarie, al variare di alcuni parametri di processo. In seguito, tramite il software Mathcad, è stata studiata la fattibilità economica per l’impianto con recupero dell’O2, mediante il calcolo del Levelised Discounted Cost (LDC) dell’unità di energia elettrica. Sono stati determinati i valori del LDC al variare della potenza netta e sono stati confrontati i risultati con i valori del LDC per le tecnologie convenzionali di produzione di energia elettrica

A General Methodology for Beached Oil Spill Hazard Mapping

The current lack of a standardized approach to compute the coastal oil spill hazard due to maritime traffic accidental releases has hindered an accurate estimate of its global impact, which is paramount to manage and intercompare the associated risks. We propose here a hazard estimation approach that is based on ensemble simulations and the extraction of the relevant distributions. We demonstrate that both open ocean and beached oil concentration distributions fit a Weibull curve, a two-parameter fat-tail probability distribution function. The simulation experiments are carried out in three different areas of the northern Atlantic. An indicator that quantify the coastal oil spill hazard is proposed and applied to the study areas

In vitro culture of Pteris vittata, an arsenic hyperaccumulating fern, for screening and propagating strains useful for phytoreme-diation

Abstract Arsenic contamination of soils and groundwater is at present one of the major emergencies in the world environmental management, and phytoremediation is a promising technology to immobilize or remove contaminants from polluted areas. The first arsenic hyperaccumulating plant, the fern Pteris vittata, was discovered only recently. It is very efficient in extracting arsenic from the soil and translocating it into its large fronds, and thus has great potential in arsenic phytoremediation. In this work, by using different hormonal formulations, we developed solid and liquid in vitro culture protocols for callus induction and maintenance, as well as for sporophyte regeneration, which are the basic tools for programmes of screening and propagation of selected strains of the fern

Functional Role of Non-Muscle Myosin II in Microglia: An Updated Review.

Myosins are a remarkable superfamily of actin-based motor proteins that use the energy derived from ATP hydrolysis to translocate actin filaments and to produce force. Myosins are abundant in different types of tissues and involved in a large variety of cellular functions. Several classes of the myosin superfamily are expressed in the nervous system; among them, non-muscle myosin II (NM II) is expressed in both neurons and non-neuronal brain cells, such as astrocytes, oligodendrocytes, endothelial cells, and microglia. In the nervous system, NM II modulates a variety of functions, such as vesicle transport, phagocytosis, cell migration, cell adhesion and morphology, secretion, transcription, and cytokinesis, as well as playing key roles during brain development, inflammation, repair, and myelination functions. In this review, we will provide a brief overview of recent emerging roles of NM II in resting and activated microglia cells, the principal regulators of immune processes in the central nervous system (CNS) in both physiological and pathological conditions. When stimulated, microglial cells react and produce a number of mediators, such as pro-inflammatory cytokines, free radicals, and nitric oxide, that enhance inflammation and contribute to neurodegenerative diseases. Inhibition of NM II could be a new therapeutic target to treat or to prevent CNS diseases

Metagenomic Analysis of Bacterial Community Structure and Dynamics of a Digestate and a More Stabilized Digestate-Derived Compost from Agricultural Waste

Recycling of different products and waste materials plays a crucial role in circular economy, where the anaerobic digestion (AD) constitutes an important pillar since it reuses nutrients in the form of organic fertilizers. Knowledge about the digestate and compost microbial community structure and its variations over time is important. The aim of the current study was to investigate the microbiome of a slurry cow digestate produced on a farm (ADG) and of a more stabilized digestate-derived compost (DdC) in order to ascertain their potential uses as organic amendments in agriculture. The results from this study, based on a partial fragment of 16S bacterial rRNA NGS sequencing, showed that there is a greater microbial diversity in the DdC originated from agricultural waste compared to the ADG. Overall, the existence of a higher microbial diversity in the DdC was confirmed by an elevated number (1115) of OTUs identified, compared with the ADG (494 OTUs identified). In the DdC, 74 bacterial orders and 125 families were identified, whereas 27 bacterial orders and 54 families were identified in the ADG. Shannon diversity and Chao1 richness indexes were higher in DdC samples compared to ADG ones (Shannon: 3.014 and 1.573, Chao1: 68 and 24.75; p< 0.001 in both cases). A possible association between the microbiome composition at different stages of composting process and the role that these microorganisms may have on the quality of the compost-like substrate and its future uses is also discussed

Expected radiation environment and damage for YBCO tapes in compact fusion reactors

We investigate the neutron damage expected in high-temperature superconducting tapes that will be employed in compact fusion reactors. Monte Carlo simulations yield the expected neutron spectrum and fluence at the magnet position, from which the primary knock-on atom energy distributions can be computed for each atomic species comprising the superconductor. This information is then employed to characterize the displacement cascades, in terms of size and morphology, through molecular dynamics simulations. The expected radiation environment is then compared with the neutron spectrum and fluences achievable at the facilities currently available for experimental investigation in order to highlight similarities and differences that could be relevant to the understanding of the radiation hardness of these materials in real fusion conditions. We find that the different neutron spectra result in different damage regimes, the irradiation temperature influences the number of generated defects, and the interaction of the neutrons with the superconductor results in a local increase in temperature. These observations suggest that further experimental investigations are needed in different regimes and that some neutron shielding will be necessary in compact fusion reactors.Funding Agencies|Italian Ministry of Education, University, and Research through Project PRIN HIBiSCUS [201785KWLE]; Programma Operativo Nazionale (PON) Ricerca e Innovazione 2014-2020; Swedish Research Council [2018-05973]; European Cooperation in Science and Technology, COST Action [CA19108]</p

CXCR4 pos circulating progenitor cells coexpressing monocytic and endothelial markers correlating with fibrotic clinical features are present in the peripheral blood of patients affected by systemic sclerosis

There is still controversy regarding the role of circulating endothelial and progenitor cells (CECs/CEPs) in the pathogenesis of systemic sclerosis (SSc). Using a sequential Boolean gating strategy based on a 4-color flow cytometric protocol, an increased number of CD31(pos)/CD184(pos)(CXCR4)/CD34(pos)/CD45(pos) and CD31(pos)/CD117(pos) (c-kit-R) /CD34(pos)/ CD45(pos) hematopoietic circulating progenitor cells (HCPCs) was detected in SSc patients compared with healthy subjects. In SSc, no circulating mature and progenitor endothelial cells were observed, while an enhanced generation of erythroid progenitor cells was found to be correlated with the presence of CD117+ HCPCs. The presence of freshly detected CXCR4posHCPC was correlated either to the in vitro cultured spindle-shaped endothelial like cells (SELC) with an endo/myelomonocytic profile or to SDF-1 and VEGF serum level. These data are related to more fibrotic clinical features of the disease, thus supporting a possible role of these cells in fibrosis

Proposal of a health care network based on big data analytics for PDs

Health care networks for Parkinson's disease (PD) already exist and have been already proposed in the literature, but most of them are not able to analyse the vast volume of data generated from medical examinations and collected and organised in a pre-defined manner. In this work, the authors propose a novel health care network based on big data analytics for PD. The main goal of the proposed architecture is to support clinicians in the objective assessment of the typical PD motor issues and alterations. The proposed health care network has the ability to retrieve a vast volume of acquired heterogeneous data from a Data warehouse and train an ensemble SVM to classify and rate the motor severity of a PD patient. Once the network is trained, it will be able to analyse the data collected during motor examinations of a PD patient and generate a diagnostic report on the basis of the previously acquired knowledge. Such a diagnostic report represents a tool both to monitor the follow up of the disease for each patient and give robust advice about the severity of the disease to clinicians