Search results for "TTR"
showing 10 items of 3945 documents
Valutazione di efficienze fotoelettriche per uno scintillatore LaBr3(Ce) tramite un approccio Virtual Point Detector
2019
L’impiego di uno scintillatore a Bromuro di Lantanio, LaBr3(Ce), come strumento di misura della attività (o concentrazione) in un dato campione, richiede la valutazione delle efficienze fotoelettriche o la conoscenza di una corrispondente curva di calibrazione. Oltre ai consueti metodi basati sull’impiego di sorgenti calibrate aventi la stessa forma e composizione del campione in esame, o metodi Monte Carlo, uno strumento rapido di valutazione delle efficienze può essere rappresentato dall'applicazione della semplificazione “Virtual Point Detector” (VPD), ovvero con il rilevatore assunto equivalente a un punto virtuale all’interno del cristallo dove si può considerare avvengano tutte le int…
Design, implementation and experimental results of an inductive power transfer system for electric bicycle wireless charging
2020
The use of renewable energy and the transformation of transport mode are crucial items for achieving an efficient and clean electrical mobility that allow being competitive on the market. In this context the interface between the power system and the Electric Vehicles (EVs) assumes a strategic role. Specifically, wireless energy transmission, based on Inductive Power Transfer (IPT), is an attractive solution for EVs charging. Moreover, the use of electric bicycles or kick scooters as mode of urban transport is continuously growing because they are lightweight, sustainable, easily parking, flexible and efficient transport devices. Owing to its benefits, the wireless power transfer can be con…
Feasibility of Ultra-Short-Term Analysis of Heart Rate and Systolic Arterial Pressure Variability at Rest and during Stress via Time-Domain and Entro…
2022
Heart Rate Variability (HRV) and Blood Pressure Variability (BPV) are widely employed tools for characterizing the complex behavior of cardiovascular dynamics. Usually, HRV and BPV analyses are carried out through short-term (ST) measurements, which exploit ~five-minute-long recordings. Recent research efforts are focused on reducing the time series length, assessing whether and to what extent Ultra-Short-Term (UST) analysis is capable of extracting information about cardiovascular variability from very short recordings. In this work, we compare ST and UST measures computed on electrocardiographic R-R intervals and systolic arterial pressure time series obtained at rest and during both post…
Causal and Non-Causal Frequency Domain Assessment of Spontaneous Baroreflex Sensitivity after Myocardial Infarction
2020
Acute myocardial infarction (AMI) is thought to alter the baroreflex control of arterial pressure. We tested this hypothesis investigating the changes of the cardiovascular response after AMI in comparison with young and old healthy controls studied at rest and during head-up tilt, using causal and non-causal frequency domain measures of the baroreflex sensitivity. Our results indicate: (i) the importance of using a causal approach that takes into account not only feedback but also feedforward effects in the study of interactions between the heart period and the arterial pressure; (ii) the compromised capacity of baroreceptors to control SAP fluctuations in post-AMI patients, both at rest a…
Synergistic and Redundant Brain-Heart Information in Patients with Focal Epilepsy
2020
In this work, partial information decomposition (PID) was applied to the time series of heart rate and EEG amplitude variability to investigate the dynamical interactions in brain-heart coupling before and after epileptic seizures. From ECG and EEG signals collected on 23 children suffering from focal epilepsy, the RR intervals and the EEG variance at ipsilateral and contralateral temporal electrodes were computed in four different time windows before and after the seizures. Static PID was used to obtain redundant, unique and synergistic components of the total information shared between the series of RR and EEG variance. Results highlight, in the progression from preictal to postictal stat…
A portable multisensor system to assess cardiorespiratory interactions through photoplethysmography
2022
Nowadays, the ever-growing interest to health and quality of life of individuals and the advancements in electronic devices technology are pushing the development of portable and wearable biomedical devices able to pursue a minimally invasive monitoring of physiological parameters in daily-life conditions. Such devices can now carry out a real-time assessment of the subjects’ overall health status and possibly even detect ongoing diseases. In this context, we have designed and implemented a multisensor portable system able to perform synchronous real-time acquisitions of electrocardiographic (ECG), photoplethysmographic (PPG) and airflow breathing signals. We investigated cardiorespiratory …
Low-invasive multisensor real-time acquisition system for the assessment of cardiorespiratory and skin conductance parameters
2022
In recent years, the attention to the health and comfort of the individual, together with the electronic miniaturization progress, have led to an increased interest in the development of biomedical devices that are able to acquire a multitude of biomedical signals. Such devices should be wearable and comfortable during daily use, to be thus suitable for continuously monitoring psychophysical health states. In this context, we have designed and realized a portable biomedical device capable of real-time acquisition of electrocardiographic (ECG), photoplethysmographic (PPG), breathing and galvanic skin response (GSR) signals, for a noninvasive monitoring of multiple physiological parameters. T…
Experimental tests on hydrogen production from seawaves energy
2017
In this paper we propose the use of Wave Energy Converter and saline water to produce hydrogen. Two different scheme and technology are proposed. The objective of this research is to design an electrolyzing system capable of utilizing sea. In particular, we present the results obtained by two different prototype of electrolyzer: one with steel electrodes and the second with titanium electrodes. Further experiments were carried out by changing the electrolytic solution of water and sodium chloride in real seawater. Finally, the electrical load has been changed as imposing electric current with a distorted waveform. © 2017 Marine Technology Society.
Deep traps in InGaN/GaN single quantum well structures grown with and without InGaN underlayers
2020
The electrical properties and deep trap spectra were compared for near-UV GaN/InGaN quantum well (QW) structures grown on free-standing GaN substrates. The structures differed by the presence or absence of a thin (110 nm) InGaN layer inserted between the high temperature GaN buffer and the QW region. Capacitance-voltage profiling with monochromatic illumination showed that in the InGaN underlayer (UL), the density of deep traps with optical threshold near 1.5 eV was much higher than in the QW and higher than for structures without InGaN. Irradiation with 5 MeV electrons strongly increased the concentration of these 1.5 eV traps in the QWs, with the increase more pronounced for samples witho…
Effects of InAlN underlayer on deep traps detected in near-UV InGaN/GaN single quantum well light-emitting diodes
2019
Two types of near-UV light-emitting diodes (LEDs) with an InGaN/GaN single quantum well (QW) differing only in the presence or absence of an underlayer (UL) consisting of an InAlN/GaN superlattice (SL) were examined. The InAlN-based ULs were previously shown to dramatically improve internal quantum efficiency of near-UV LEDs, via a decrease in the density of deep traps responsible for nonradiative recombination in the QW region. The main differences between samples with and without UL were (a) a higher compensation of Mg acceptors in the p-GaN:Mg contact layer of the sample without UL, which correlates with the presence of traps with an activation energy of 0.06 eV in the QW region, (b) the…