472 research outputs found
Synthetic strategies for the enhancement of Mg(OH)2 thermochemical performances as heat storage material
Abstract This work deals with the study of influence of multi walled carbon nanotubes (CNTs) characteristics on thermochemical performance of hybrid materials based on Mg(OH) 2 (M) as heat storage medium. Two different functionalized CNTs samples are investigated, separated curly tubes (SN) and bundles of straight nanotubes (BN). Hybrids were synthesized by reverse deposition precipitation method and their structure was characterized by X-ray analysis and scanning electron microscopy. The heat storage performance was studied through a thermogravimetric apparatus, simulating heat storage/release cycles. It is demonstrated that separated CNTs owning mainly carboxylic groups increase the interaction with precipitated magnesium hydroxide, improving the reacted fraction during dehydration/hydration cycle. In terms of dehydration/hydration conversion the samples' rank is SN-M>Mg(OH) 2 >BN-M. SN-M exhibits higher heat storage/output capacity (~1250 kJ/kg Mg(OH)2 , ~350 MJ/m 3 )
Influence of the Cobalt Phase on the Highly Efficient Growth of MWNTs
In this work, the influence of the cobalt phase on the growth of carbon nanotubes by the catalytic chemical vapour deposition of CH4 with catalysts containing Co, Mo and Mg is investigated. To this end, the catalytic behaviour of physically mixed CoO/MgO+MgMoO4 and CoMoO4+MgMoO4 is studied. The results obtained show that CoMoO4+MgMoO4 allows for the attainment of the highest CNT yield (2407 wt % against 1296 wt %). Its higher activity is ascribed to the greater formation of active sites that, in light of current assessments, are constituted by metallic cobalt adjacent to Mo2C, and the huge exfoliation of the catalyst, which contributes towards enhancing their exposure
The golden fig: a plasmonic effect study of organic-based solar cells
An optimization work on dye-sensitized solar cells (DSSCs) based on both artificial and natural dyes was carried out by a fine synthesis work embedding gold nanoparticles in a TiO(2) semiconductor and perfecting the TiO(2) particle sizes of the scattering layer. Noble metal nanostructures are known for the surface plasmon resonance peculiarity that reveals unique properties and has been implemented in several fields such as sensing, photocatalysis, optical antennas and PV devices. By embedding gold nanoparticles in the mesoporous TiO(2) layer and adding a scattering layer, we were able to boost the power conversion efficiency (PCE) to 10.8%, using an organic ruthenium complex. The same implementation was carried out using a natural dye, betalains, extracted from Sicilian prickly pear. In this case, the conversion efficiency doubled from 1 to 2% (measured at 1 SUN illumination, 100 mW/cm(2) under solar simulation irradiation). Moreover, we obtained (measured at 0.1 SUN, 10 mW/cm(2) under blue light LED irradiation) a record efficiency of 15% with the betalain-based dye, paving the way for indoor applications in organic natural devices. Finally, an attempt to scale up the system is shown, and a betalain-based- dye-sensitized solar module (DSSM), with an active area of 43.2 cm(2) and a PCE of 1.02%, was fabricated for the first time
On the CVD Growth of C Nanotubes Over Fe-Loaded Montmorillonite Catalysts
The synthesis of carbon nanotubes (CNTs) by
chemical vapor deposition (CVD) of isobutane (iâC4H10)
over sodiumâexchanged K10âmontmorillonite based ironâ
catalysts is investigated. By studying the influence of
ironâaddition (5â25wt%) on the catalyst performances, at
700 °C, an empirical relationship is derived relating the
mass of CNTs synthesized with the exposed surface of
loaded iron, as resulting from simultaneous change of
number, size and dispersion of Feânanoparticles available
for the growth
Post-stroke aphasia at the time of COVID-19 pandemic: a telerehabilitation perspective
We report on our remote speech therapy experience in post-stroke aphasia. The aim was to test the feasibility and utility of telerehabilitation to support future randomized controlled trials. Post-stroke aphasia is a common and disabling speech disorder, which significantly affects patients' and caregivers' health and quality of life. Due to COVID-19 pandemic, most of the conventional speech therapy approaches had to stop or "switch" into telerehabilitation procedures to ensure the safety of patients and operators but, concomitantly, the best rehabilitation level possible. Here, we planned a 5-month telespeech therapy programme, twice per week, of a patient with non-fluent aphasia following an intracerebral haemorrhage. Overall, treatment adherence based on the operator's assessments was high, and incomplete adherence for technical problems occurred very rarely. In line with the patient's feedback, acceptability was also positive, since he was constantly motivated during the sessions and the exercises performed autonomously, as confirmed by the speech therapist and caregiver, respectively. Moreover, despite the sequelae from the cerebrovascular event, evident in some writing tests due to the motor deficits in his right arm and the disadvantages typical of all telepractices, more relevant results were achieved during the telerehabilitation period compared to those of the "face-to-face" therapy before the COVID-19 outbreak. The telespeech therapy performed can be considered successful and the patient was able to return to work. Concluding, we support it as a feasible approach offering patients and their families the opportunity to continue the speech and language rehabilitation pathway, even at the time of pandemic
Post-exercise high-sensitivity troponin T levels in patients with suspected unstable angina
Background
Previous studies showed that troponin blood levels may increase after exercise. In this
study we assessed whether, among patients admitted with suspected unstable angina, the
increase in high-sensitive troponin T (hs-TnT) levels after exercise stress test (EST) might
help identify those with obstructive coronary artery disease (CAD) and predict symptom
recurrence during short term follow-up.
Methods
Maximal treadmill EST was performed in 69 consecutive patients admitted to the emergency
room with a suspicion of unstable angina (acute chest pain but confirmed normal
serum levels of cardiac troponins) was measured before and 4 hours after EST. Coronary
angiography was performed in 22 patients (32.8%).
Results
hs-TnT increased after EST compared to baseline in the whole population (from 0.84\ub10.65
to 1.17\ub10.87 ng/dL, p<0.001). The increase was similar in patients with positive (n = 14)
and negative (n = 55) EST (p = 0.72), and was also similar in patients with (n = 12) and without
(n = 10) obstructive CAD at angiography (p = 0.91). The achievement of a heart rate at
peak EST \ufffd85% of that predicted for age was the variable mainly associated with the post-
EST hs-TnT increase at multivariable linear regression analysis (p = 0.005). The change
after EST of hs-TnT did not predict the recurrence of symptoms or readmission for chest
pain at 6-month follow-up.
Conclusions
Our data show that hs-TnT increased after EST in patients with suspected unstable angina,
which seemed largely independent of most clinical and laboratory variables. Thus, hs-TnT
assessed after EST does not seem to be helpful to identify patients with obstructive CAD in
this kind of patients
Respiratory physiotherapy in patients with COVID-19 infection in acute setting: a Position Paper of the Italian Association of Respiratory Physiotherapists (ARIR)
Respiratory physiotherapy in patients with COVID-19 infection in acute setting: a Position Paper of the Italian Association of Respiratory Physiotherapists (ARIR)
On February 2020, Italy, especially the northern regions, was hit by an epidemic of the new SARS-Cov-2 coronavirus that spread from China between December 2019 and January 2020. The entire healthcare system had to respond promptly in a very short time to an exponential growth of the number of subjects affected by COVID-19 (Coronavirus disease 2019) with the need of semi-intensive and intensive care units
The Long-Baseline Neutrino Experiment: Exploring Fundamental Symmetries of the Universe
The preponderance of matter over antimatter in the early Universe, the
dynamics of the supernova bursts that produced the heavy elements necessary for
life and whether protons eventually decay --- these mysteries at the forefront
of particle physics and astrophysics are key to understanding the early
evolution of our Universe, its current state and its eventual fate. The
Long-Baseline Neutrino Experiment (LBNE) represents an extensively developed
plan for a world-class experiment dedicated to addressing these questions. LBNE
is conceived around three central components: (1) a new, high-intensity
neutrino source generated from a megawatt-class proton accelerator at Fermi
National Accelerator Laboratory, (2) a near neutrino detector just downstream
of the source, and (3) a massive liquid argon time-projection chamber deployed
as a far detector deep underground at the Sanford Underground Research
Facility. This facility, located at the site of the former Homestake Mine in
Lead, South Dakota, is approximately 1,300 km from the neutrino source at
Fermilab -- a distance (baseline) that delivers optimal sensitivity to neutrino
charge-parity symmetry violation and mass ordering effects. This ambitious yet
cost-effective design incorporates scalability and flexibility and can
accommodate a variety of upgrades and contributions. With its exceptional
combination of experimental configuration, technical capabilities, and
potential for transformative discoveries, LBNE promises to be a vital facility
for the field of particle physics worldwide, providing physicists from around
the globe with opportunities to collaborate in a twenty to thirty year program
of exciting science. In this document we provide a comprehensive overview of
LBNE's scientific objectives, its place in the landscape of neutrino physics
worldwide, the technologies it will incorporate and the capabilities it will
possess.Comment: Major update of previous version. This is the reference document for
LBNE science program and current status. Chapters 1, 3, and 9 provide a
comprehensive overview of LBNE's scientific objectives, its place in the
landscape of neutrino physics worldwide, the technologies it will incorporate
and the capabilities it will possess. 288 pages, 116 figure
Standalone vertex ïŹnding in the ATLAS muon spectrometer
A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at âs = 7 TeV collected with the ATLAS detector at the LHC during 2011
Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC
Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H âÎł Îł, H â Z Zâ â4l and H âW Wâ âlÎœlÎœ. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of âs = 7 TeV and âs = 8 TeV, corresponding to an integrated luminosity of about 25 fbâ1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined ïŹts probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson
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