Neural networks for small scale ORC optimization

This study concerns a thermodynamic and technical optimization of a small scale Organic Rankine Cycle system for waste heat recovery applications. An Artificial Neural Network (ANN) has been used to develop a thermodynamic model to be used for the maximization of the production of power while keeping the size of the heat exchangers and hence the cost of the plant at its minimum. R1234yf has been selected as the working fluid. The results show that the use of ANN is promising in solving complex nonlinear optimization problems that arise in the field of thermodynamics

Detriti Spaziali (Contratto ASI n° I/046/07/0) e Primo Atto Aggiuntivo Nota Tecnica RA5 “Quinto Rapporto di Avanzamento”

Questo documento riassume le attività svolte nell’ambito del quarto anno del Progetto ASI Detriti Spaziali (Contratto ASI No. I/046/07/0), dalla IV alla V Riunione di Avanzamento e del Primo Atto Aggiuntivo al contratto. 1) Per le misure ottiche (WP110), di responsabilità di UNIRM1, sono proseguite le attività di osservazioni ottiche e si è migliorata l’automazione dell’osservatorio SpaDE. E’ stata analizzata la possibilità di effettuare misure spettrometriche con l’osservatorio di Toppo di Castelgrande. Per il Contributo di altri osservatori (WP111) vengono presentati i risultati delle osservazioni congiunte con gli osservatori amatoriali di Massa d’albe e Anguillara. Vengono riportati i risultati finali relativi all’analisi di immagini di campagne osservative congiunte con CNES e JAXA. Inoltre viene illustrata la rete di osservatori italiani e internazionali coordinati dal GAUSS. 2) Per il Monitoraggio in-situ (WP130), di responsabilità di UNIRM, sono iniziate le prove di sensibilità dei trasduttori piezoelettrici e la revisione dell’elettronica. Le prove di impatto iperveloce per la calibrazione saranno effettuate congiuntamente a CISAS. 3) Per le misure radar (WP120a), di responsabilità IRA-OATO dell’INAF, è presentato lo studio elettromagnetico dell’antenna VLBI di Medicina effettuato allo scopo di valutare la possibilità di installare un sistema ricevente in piggy-back. Nel periodo in esame è stata effettuata la campagna osservativa con il sistema radar multistatico (Evpatoria-Medicina-Ventspils) e una campagna di test per localizzare delle sorgenti di interferenza. Infine, è stata ultimata la realizzazione dello spettrometro installato su schede basate su FPGA. 4) Per le misure radar (WP120b), di responsabilità ISAC-CNR, è iniziato lo spostamento della stazione nel nuovo campo di Villa Sant’Elia in località Campi Salentina (LE). Sono proseguite le osservazioni mensili dei detriti al rientro in atmosfera. Sono stati calcolati giornalmente i rapporti percentuali dei flussi dei debris rispetto ai flussi totali, i flussi medi dei debris su ogni periodo. Dall’analisi dei dati storici si è osservato un generale incremento delle percentuali dei debris nei mesi del 2010 rispetto ai corrispondenti mesi del 2009. Questo e stato messo in relazione al notevole numero dei frammenti aggiuntivi in LEO prodotti dai citati eventi Fengyun 1C, Cosmos 2251 e Iridium 33. 5) Per la modellazione (WP200) e la mitigazione (WP400), è continuata la caratterizzazione delle nubi di detriti collisionali di Fengyun 1C, Cosmos 2251 e Iridium 33. Sono inoltre ripartite le attività connesse con l’AI 27.1, per la valutazione della necessità di un Active Debris Removal in LEO, e si è svolta con successo la campagna test di rientro 2010-1. E’ proseguita l’attività nell’ambito degli AI 22.2, 26.2 e 27.2, relativamente all’aggiornamento e al supporto delle IADC Mitigation Guidelines e alla valutazione del rischio rappresentato dai rientri. 6) Per la protezione (WP310 e 330), di responsabilità CISAS, sono presentati i risultati degli ultimi esperimenti di impatto effettuati a supporto dell’AI 26-1 IADC per la caratterizzazione di ejecta da satellite. E’ riportato l’esito della valutazione di diversi sensori per la caratterizzazione degli ejecta, oltre che lo studio del fenomeno di produzione di frammenti secondari in seguito ad impatti obliqui. Sono state affinate le tecniche di simulazione della generazione di ejecta mediante hydrocode. Infine, e stato predisposto un software specifico per il Risk Assessment, che consente di utilizzare MASTER e ORDEM come modelli di ambiente e implementa varie equazioni di danno per il calcolo della resistenza balistica del sistema. Lo stesso software consente di stimare il flusso detritico secondario originato a seguito della produzione di ejecta da impatto iperveloce su superfici di veicoli spaziali

Low doses of pristine and oxidized single-wall carbon nanotubes affect mammalian embryonic development

Several in vitro and in vivo studies suggest local and systemic effects following exposure to carbon nanotubes. No data are available, however, on their possible embryotoxicity in mammals. In this study, we tested the effect of pristine and oxidized single-wall carbon nanotubes (SWCNTs) on the development of the mouse embryo. To this end, SWCNTs (from 10 ng to 30 \u3bcg/mouse) were administered to female mice soon after implantation (postcoital day 5.5); 10 days later, animals were sacrificed, and uteri, placentas, and fetuses examined. A high percentage of early miscarriages and fetal malformations was observed in females exposed to oxidized SWCNTs, while lower percentages were found in animals exposed to the pristine material. The lowest effective dose was 100 ng/mouse. Extensive vascular lesions and increased production of reactive oxygen species (ROS) were detected in placentas of malformed but not of normally developed fetuses. Increased ROS levels were likewise detected in malformed fetuses. No increased ROS production or evident morphological alterations were observed in maternal tissues. No fetal and placental abnormalities were ever observed in control animals. In parallel, SWCNT embryotoxicity was evaluated using the embryonic stem cell test (EST), a validated in vitro assay developed for predicting embryotoxicity of soluble chemical compounds, but never applied in full to nanoparticles. The EST predicted the in vivo data, identifying oxidized SWCNTs as the more toxic compound

Safety and efficacy of COVID-19 vaccines in patients on dialysis: a multicentre cohort study in Italy

Background The aim of this study was to evaluate the efficacy and safety of COVID-19 vaccines in patients undergoing haemodialysis in Italy compared to the general population.Methods In this cohort study, 118 dialysis centres from 18 Italian Regions participated. Individuals older than 16 years on dialysis treatment for at least 3 months, who provided informed consent were included. We collected demographic and clinical information, as well as data on vaccination status, hospitalisations, access to intensive care units and adverse events. We calculated the incidence, hospitalisation, mortality, and fatality rates in the vaccinated dialysis cohort, adjusted for several covariates. The incidence rates of infection in the dialysis cohort and the general population were compared through Standardised Incidence Rate Ratio.Results The study included 6555 patients vaccinated against SARS-CoV-2 infection according to the schedule recommended in Italy. Between March 2021 and May 2022, there were 1096 cases of SARS-CoV-2 infection, with an incidence rate after completion of the three-dose vaccination cycle of 37.7 cases per 100 person-years. Compared to the general population, we observed a 14% reduction in the risk of infection for patients who received three vaccine doses (Standardised Incidence Rate Ratio: 0.86; 95% Confidence Interval: 0.81-0.91), whereas no statistically significant differences were found for COVID-19-related hospitalisations, intensive care unit admissions or death. No safety signals emerged from the reported adverse events.Conclusions The vaccination program against SARS-CoV-2 in the haemodialysis population showed an effectiveness and safety profile comparable to that seen in the general population

Safety and efficacy of COVID-19 vaccines in patients on dialysis: a multicentre cohort study in Italy

Background The aim of this study was to evaluate the efficacy and safety of COVID-19 vaccines in patients undergoing haemodialysis in Italy compared to the general population.Methods In this cohort study, 118 dialysis centres from 18 Italian Regions participated. Individuals older than 16 years on dialysis treatment for at least 3 months, who provided informed consent were included. We collected demographic and clinical information, as well as data on vaccination status, hospitalisations, access to intensive care units and adverse events. We calculated the incidence, hospitalisation, mortality, and fatality rates in the vaccinated dialysis cohort, adjusted for several covariates. The incidence rates of infection in the dialysis cohort and the general population were compared through Standardised Incidence Rate Ratio.Results The study included 6555 patients vaccinated against SARS-CoV-2 infection according to the schedule recommended in Italy. Between March 2021 and May 2022, there were 1096 cases of SARS-CoV-2 infection, with an incidence rate after completion of the three-dose vaccination cycle of 37.7 cases per 100 person-years. Compared to the general population, we observed a 14% reduction in the risk of infection for patients who received three vaccine doses (Standardised Incidence Rate Ratio: 0.86; 95% Confidence Interval: 0.81-0.91), whereas no statistically significant differences were found for COVID-19-related hospitalisations, intensive care unit admissions or death. No safety signals emerged from the reported adverse events.Conclusions The vaccination program against SARS-CoV-2 in the haemodialysis population showed an effectiveness and safety profile comparable to that seen in the general population

Impact of COVID-19 vaccines in patients on hemodialysis: an Italian multicentre cohort study

BackgroundThe aim of this study was to evaluate the impact on the national health system of COVID-19 infection in vaccinated patients undergoing haemodialysis.MethodsFrom the cohort of vaccinated dialysis patients enrolled in 118 dialysis centres, we calculated hospitalisation incidence in COVID-19-infected subjects. COVID-19-related hospitalisations and ICU admissions were analysed over two time periods (prior to administration of the third dose and following administration of the third dose of vaccine) and adjusted for several co-variates. Using the general population as the reference, we then calculated the Standardized Incidence Ratio (SIR) of hospitalisation.ResultsEighty-two subjects out of 1096 infected patients were hospitalised (7.5%) and sixty-four hospitalisations occurred among the 824 infected persons after the third dose. Age >= 60 years (Adj RR 2.91; 95% CI 1.34-6.30) and lung disease (Adj RR = 2.45; 95% CI 1.32-4.54) were the only risk factors associated with hospitalisation. The risk of ICU admission in the second time period (Time 2) was reduced by 86% (RR = 0.14; 95% CI 0.03-0.71) compared to the first time period (Time 1). The SIR of hospitalisation (SIR 14.51; 95% CI 11.37-17.65) and ICU admission (SIR 14.58; 95% CI 2.91-26.24) showed an increase in the number of events in dialysis patients compared to the general population.ConclusionsOur analysis revealed that while the second variant of the virus increased infection rates, it was concurrently associated with mitigated severity of infections. Dialysis patients exhibited a higher susceptibility to both COVID-19 hospitalisation and ICU admission than the general population throughout the pandemic