935 research outputs found
The Latin Leaflet, Number 29
Polymer electrolytes represent the ultimate in terms of desirable properties of energy storage/conversion devices, as they can offer an all-solid-state construction, a wide variety of shapes and sizes, light-weight, low costs, high energy density and safety.
Here we present our recent results concerning a novel strategy for preparing efficient polymer membranes which are successfully demonstrated as suitable electrolytes for several energy conversion and storage devices (i.e., Li- and Na-based batteries and DSSCs). Highly ionic conducting polymer electrolytes containing PEO-based functionalities and different components (e.g., Li/Na salts, RTILs, natural biosourced and cellulosic fillers) are successfully prepared via a rapid process and, directly or subsequently, cross-linked via UV irradiation (patent pending, PCT/IT2014/000008). All the prepared materials are thoroughly characterised in terms of their physical, chemical and morphological properties and tested for their electrochemical performances and durability. The UV-curing process on such materials led to the production of elastic and resistant amorphous macromolecular networks. Noticeably increased ionic conductivities are registered (10-3 S cm-1 at RT), along with very stable interfacial and storage stability and wide electrochemical stability windows. The different lab-scale solid-state devices show remarkable performances even at ambient temperature, at the level of those using liquid electrolytes, respect to which demonstrate much greater durability and safety.
The obtained findings demonstrate a new, easy and low cost approach to fabricate and tailor-make polymer electrolytes with highly promising prospects for the next generation of advanced flexible energy production and storage devices
Analysis of seismically-isolated two-block systems using a multiârocking-body dynamic model
A novel multibody rocking model is developed to investigate the dynamic response of two stacked rigid blocks placed on a linear base isolation device. The model is used to investigate the dynamic response of a realistic statue-pedestal system subject to pulse-like ground motions. The analysis shows that, in general, base isolation increases the safety level of the rocking system. However, for large period pulses or small size blocks, the isolator can amplify the ground motion, resulting in a lower minimum overturning acceleration than for the nonisolated system. Further, the amplification or shock spectrum of a linear mass-dashpot-spring oscillator, was found to be the reciprocal of the minimum nondimensional overturning acceleration of the investigated rocking system. Novel rocking spectra are obtained by normalizing the frequency of the pulse by the frequency of the isolator. The analysis also demonstrates how the dynamic response of the two stacked blocks is equivalent to that of a single-block configuration coincident with the whole system assumed monolithic or the upper block alone, whichever is more slender
Monitoring DC anode current of a grounded-cathode photomultiplier tube
Abstract The Pierre Auger Observatories (PAO) for the highest energy cosmic rays will make use of both the Cherenkov and Air Fluorescence techniques. Surface Detectors (SD) and Fluorescence Detectors (FD) will have to operate in a desert-type environment during at least 15 years. In order to avoid dust deposition, due to electrostatics, and other practical inconveniences derived from biasing the cathode with a negative potential, the 15 000 PMTs of the FD will operate in the grounded cathode configuration. Despite the fact that the anodes will remain at high voltage with respect to ground, the DC anode current, which varies with background light, will have to be recorded. We have developed a current monitoring system based on a novel optocoupled feedback circuit that allows sensitive, linear, and temperature-independent measurements of the DC anode current. A distinctive feature of this circuit is that it uses optical coupling between passive components at high voltage and active components near the ground potential. This represents a substantial improvement over classical solutions which require the supply of power to an active circuit at high voltage. We report on the first tests performed with both active and passive biasing networks which demonstrate the validity of this new method
Evaluation of predictive models for post-fire debris flow occurrence in the western United States
Abstract. Rainfall-induced debris flows in recently burned mountainous areas cause
significant economic losses and human casualties. Currently, prediction of
post-fire debris flows is widely based on the use of power-law thresholds and
logistic regression models. While these procedures have served with certain
success in existing operational warning systems, in this study we investigate
the potential to improve the efficiency of current predictive models with
machine-learning approaches. Specifically, the performance of a predictive
model based on the random forest algorithm is compared with current techniques
for the prediction of post-fire debris flow occurrence in the western United
States. The analysis is based on a database of post-fire debris flows
recently published by the United States Geological Survey. Results show that
predictive models based on random forest exhibit systematic and considerably
improved performance with respect to the other models examined. In addition,
the random-forest-based models demonstrated improvement in performance with
increasing training sample size, indicating a clear advantage regarding their
ability to successfully assimilate new information. Complexity, in terms of
variables required for developing the predictive models, is deemed important but
the choice of model used is shown to have a greater impact on the overall
performance
Mobile Cloud Support for Semantic-Enriched Speech Recognition in Social Care
Nowadays, most users carry high computing power mobile devices where speech recognition is certainly one of the main technologies available in every modern smartphone, although battery draining and application performance (resource shortage) have a big impact on the experienced quality. Shifting applications and services to the cloud may help to improve mobile user satisfaction as demonstrated by several ongoing efforts in the mobile cloud area. However, the quality of speech recognition is still not sufficient in many complex cases to replace the common hand written text, especially when prompt reaction to short-term provisioning requests is required. To address the new scenario, this paper proposes a mobile cloud infrastructure to support the extraction of semantics information from speech recognition in the Social Care domain, where carers have to speak about their patients conditions in order to have reliable notes used afterward to plan the best support. We present not only an architecture proposal, but also a real prototype that we have deployed and thoroughly assessed with different queries, accents, and in presence of load peaks, in our experimental mobile cloud Platform as a Service (PaaS) testbed based on Cloud Foundry
Effect of manidipine-simvastatin combination on fibrinolysis, adhesion molecules and C-reactive protein in hypertensive hypercholesterolemic patients
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Effect of telmisartan and ramipril on atrial fibrillation recurrence and severity in hypertensive patients with metabolic syndrome and recurrent symptomatic paroxysmal and persistent atrial fibrillation
This study evaluated the effect of telmisartan, ramipril, and amlodipine on atrial fibrillation (AF) recurrence and severity in hypertensive patients with metabolic syndrome. A total of 391 hypertensive outpatients with metabolic syndrome, in sinus rhythm but with at least 2 episodes of AF in the previous 6 months were randomized to telmisartan, ramipril, or amlodipine for 1 year. At the first AF, ventricular rate (VR) and plasma cardiac troponin I (TnI) were evaluated. P-wave dispersion (PWD) and procollagen type I carboxy-terminal peptide (PIP) were evaluated before and after 12 months of treatment. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were similarly and significantly reduced by all treatments (P < .001). In all, 49\% of patients treated with amlodipine had a recurrence of AF as did 25.5\% of patients with ramipril and 12.9\% of patients with telmisartan (P < .01 vs amlodipine and P < .05 vs ramipril). Ventricular rate and TnI at the first AF recurrence were significantly lower with telmisartan and ramipril than with amlodipine. P-wave dispersion was reduced by ramipril (-5.1 ms, P < .05) and even more by telmisartan (-11 ms, P < .01). Telmisartan and ramipril induced a similar PIP reduction (-52.8 and -49.8 ”g/L, respectively, P < .01). These findings suggested that in these patients telmisartan was more effective than ramipril in reducing AF recurrence and severity as well as in improving PWD, despite a similar BP reduction and a similar improvement in cardiac fibrosis. This could be related to a specific effect of telmisartan on atrial electric remodeling
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