391 research outputs found
Comparison of pure and mixed gas permeation of the highly fluorinated polymer of intrinsic microporosity PIM-2 under dry and humid conditions: Experiment and modelling
This manuscript describes the gas separation performance of PIM-2, a partially fluorinated linear copolymer synthesized from 5,5',6,6'-tetrahydroxy-3,3,3',3'-tetramethylspirobisindane (TTSBI) and decafluorobiphenyl (DFBP). As one of the early members of the family of polymers of intrinsic microporosity, it had never been tested as a gas separation membrane because of insufficient mechanical resistance. This has been solved only recently, allowing the preparation of robust self-standing films. Molecular modelling studies demonstrated a high fractional free volume (34%) and an elevated surface area (642 m2 g-1), and the latter is in good agreement with experimental BET results. Pure gas permeabilities measured on a fixed-volume time-lag instrument at 1 bar compare well with the results of mixed separation tests on a variable volume setup from 1-6 bar(a). Molecular modelling and independent sorption measurements on a gravimetric sorption balance both show strong dual-mode sorption behaviour, especially for CO2 and to a lesser extent for CH4. Temperature-dependent pure gas permeation measurements show typical Arrhenius behaviour, with a clear increase in the activation energy for diffusion with the increasing molecular size of the gas, indicating high size-selectivity. This is in agreement with the highly rigid PIM structure, determined by AFM force spectroscopy measurements. The dual-mode behaviour results in a moderate pressure dependence of the CO2 permeability and the CO2/N2 and CO2/CH4 selectivity, all slightly decreasing with increasing pressure. The presence of humidity in the gas stream has a remarkable small effect on the membrane performance, which is probably due to the high fluorine content and the consequently low water vapour solubility in the polymer, as confirmed by gravimetric sorption measurements. The manuscript describes an extensive study on the structure-property relationships in PIM-2. © 2019 Elsevier B.V.European Commission, EC Grantová Agentura Ceské Republiky, GA Ä?R: 18-05484S --Research on biogas upgrading presented in this work was supported by EU structural funding in the frame of Operational Programme Research, Development and Education, project No. CZ.02.1.01./0.0/0.0/17_049/0008419 “COOPERATION”. This work was further supported by the CNR-CAS bilateral agreement 2016–2018 “Innovative polymeric membranes for pervaporation and advanced gas and vapour separations” and by the Czech Science Foundation (grant no. 18-05484S ). Appendix A -
Application of kaolin and italian natural chabasite-rich zeolitite to mitigate the effect of global warming in vitis vinifera l. Cv. sangiovese
High temperatures and the anomalous distribution of rainfall during the growing season may have a negative impact on grapevine yield and berry composition. In recent years, many studies have focused on the application of agronomical techniques to reduce the negative impact of heat waves on secondary metabolites such as phenols. In particular, treatments with kaolin have shown positive effects on reducing canopy temperatures, enhancing the accumulation of anthocyanins. In regard to the above, three treatments were evaluated: untreated control (C), kaolin (CAO), and chabasite-rich zeolitites (ZEO) applications on cv. Sangiovese in order to verify the cooling effects on leaves and bunches, and the impact on gas exchange, yield parameters, berry composition, and on both chemical and sensory notes of wine. Minerals were sprayed twice around the veraison on the entire canopy at a 3% concentration. The results showed that the application of the minerals was able to reduce the berry temperatures in both years of the trial as compared to the untreated control (C), without affecting vine gas exchange, yield, and soluble solid accumulation. Furthermore, the cooling effect determined an increase in anthocyanin on both the grapes and the wine. At testing, CAO and ZEO wines stood out regarding greater color intensity and were preferred by the judges
Sudden hearing loss in sarcoidosis: otoneurological study and neuroradiological correlates
Sarcoidosis is an inflammatory multisystem disorder of unknown cause. Approximately 5-7% of patients manifest symptoms of central nervous system involvement, or neurosarcoidosis. Cranial neuropathy usually entails facial nerve palsy and optic neuritis. Sudden hearing loss has been reported in fewer than 20 cases. Herewith, two new cases of sudden hearing loss due to probable neurosarcoidosis are reported, each having a quite different clinical course. In one case, unilateral sudden hearing loss and facial palsy were the presenting symptoms of systemic sarcoidosis, while in the second, unilateral sudden deafness occurred despite ongoing immunosuppressive treatment for systemic sarcoidosis
Tolerance of Anadenanthera peregrina to Eucalyptus camaldulensis and Eucalyptus grandis essential oil as condition for mixed plantation.
With the purpose of selecting the species of woody Caatinga for mixed plantations with Eucalyptus spp., the allelophatic effects of E. camaldulensis and E. grandis essential oil were studied on the growth activities of Anadenanthera peregrina. The plants were closed in glass chambers in the presence of volatile oil of E. camaldulensis or E. grandis at the concentration of 13 nl.cm-3. The number of leaves, height and diameter at soil lever were compared before, immediately after and after 30 days. Chlorophyll a and b, carotenoids and dry mass were evaluated after the treatment application. There was no inhibitory effect of E. camaldulensis and E. grandis oils on A. peregrina. E. camaldulensis, which was more adapted to semi-arid conditions, was planted in mixture stands with two native legume species, inoculated with Rhizobium and arbuscular mycorrhizal fungi. E. camaldulensis did not inhibit native species growth after two years of cultivation
Mechanical analysis of the ENEA TF coil proposal for the EU DEMO fusion reactor
The design of the superconducting magnet system of the European DEMO fusion reactor is currently being pursued in the framework of the EUROfusion Magnets Work Package (WPMAG). Three alternative winding pack (WP) options for the Toroidal Field Coils (TFCs) are being proposed by different research units, each featuring a different conductor manufacturing technology (react-and-wind vs. wind-and-react) or winding layout (layer vs. pancake).
One of the options (namely, WP#2), proposed by Italian ENEA, features a layer-wound WP design adopting a wind-and-react conductor with rectangular cross section with high aspect ratio, obtained squeezing an initially circular conductor.
In order to assess the capability of all the TFC components to withstand the electromagnetic loads due to the huge Lorentz forces without any structural failure during the magnet lifetime, the mechanical analysis of the 2016 version of the WP#2 design option is performed here applying a hierarchical approach herein defined as the Stress Recovery Tool (SRT): the Finite Element Analysis (FEA) of a whole magnet (including the casing) is performed at a low computational cost adopting a coarse WP model with smeared (homogenized) properties. The displacements computed on the smeared WP are then used as boundary conditions for a refined FEA of some WP slices, located in selected (critical) poloidal positions, where all the conductors detailed features (jacket, insulations) are properly accounted for
A Project to Promote English Learning in Primary School: “An English Island®” E-learning Platform
The present study was aimed to investigate English learning as second language, in school, in first, second and third graders of twelve classes randomly assigned to a control or an experimental group. Children in the latter are exposed during English school teaching to the method “An English Island®” and to its platform activities. The method “An English Island®” offers a variety of strategies for teaching English in primary school, an innovative digital tool that promotes teaching/learning English language’s communicative approach, lead students to become familiar with the language in a sort of continuous, inclusive workout, in which everyone participates and talks. English skills as well as cognitive abilities are tested in both groups at the beginning and at the end of the school year with the aim to compare control and experimental classes in both a longitudinal and a cross-sectional design
Adattamento precoce dell’impianto cocleare in età pediatrica
L’impianto cocleare costituisce una valida opportunità per fornire l’accesso alla stimolazione uditiva nei casi di ipoacusia severa o profonda di origine cocleare. E’ stato ampiamente dimostrato che l’impianto cocleare è una soluzione sicura ed efficace e che la precocità nell’attivazione è associata a risultati migliori. E’ importante studiare le variabili e gli aspetti che possono interferire con un adattamento precoce e un adeguato accesso al mondo sonoro: caratteristiche del bambino, alleanza terapeutica con la famiglia, aspetti tecnici, medici e organizzativi. Obiettivo di questo lavoro è quello di proporre raccomandazioni utili per gli aspetti organizzativi-pratici relativi alle attivazioni precoci di impianto cocleare, attraverso un particolare modello di analisi SWOT e TOWS
To Splint or Not to Splint Short Dental Implants Under the Same Partial Fixed Prosthesis? One-year Post-loading Data From a Multicentre Randomised Controlled Trial
PURPOSE. To compare the clinical outcomes of two adjacent 6-mm-long dental implants splinted under the same prosthesis (control group) versus two identical implants sup-porting single crowns (test group). MATERIALS AND METHODS. Forty-seven patients with edentulous posterior (premolars and/or molars) jaws received two adjacent 6-mm-long dental implants, which were sub-merged. Four months later, at impression taking, patients were randomised to receive splinted or unsplinted definitive cemented metal-composite prostheses. Unfortunately, four patients died before randomisation and three patients lost five implants, so only 40 patients were randomised, according to a parallel-group design, to have both implants splinted under the same partial fixed prosthesis (19 patients) or with two single crowns (21 patients). Outcome measures were: prosthesis and implant failures, any complica-tions, peri-implant marginal bone level changes and patient satisfaction. Patients were followed-up to 1 year after loading. RESULTS. One patient from the splinted group dropped out. No implant failures occurred after randomisation. One complication occurred in the unsplinted group versus no complications at splinted implants, the difference not being statistically different (Fisher’s exact test P = 1.000; difference in proportions =-0.04; 95% CI-0.16 to 0.09). Both groups presented significant peri-implant marginal bone loss at 1 year after loading (P<0.05), respectively-0.36 (0.45) mm at splinted implants and-0.17 (0.31) mm at unsplinted implan-ts, but there were no statistically significant differences between the two groups (mean difference 0.19 mm; 95% CI-0.10 to 0.48; P = 0.194). All patients were fully or reasonably satisfied with the treatment, with the exception of two patients, both from the splinted group: one patient was not sure about the aesthetics, and another would not undergo the same treatment again. CONCLUSIONS. The present data seems to suggest that up to 1 year after loading the prognosis of short implants, mostly placed in mandibles characterised by dense bone quality, may not be influenced by splinting or not under the same fixed prostheses. Howe-ver, these preliminary results need to be confirmed by larger trials with follow-ups of at least 5 years
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