Search results for "O2"
showing 10 items of 1115 documents
Can Green Dimethyl Carbonate Synthesis be More Effective? A Catalyst Recycling Study Benefiting from Experimental Kinetics and DFT Modeling
2014
Dibutyldimethoxystannanes are known to catalyze the reaction between carbon dioxide and methanol leading to dimethyl carbonate. Despite similarities between din-butyl- and ditert-butyldimethoxystannane, the recycled complexes have different structural features. In the din-butyl series, a decatin(IV) complex has been characterized and is less active than the stannane precursor. Kinetic experiments likely indicate that all the tin centers are not active, which is confirmed in comparing with the related dinuclear 1,3-dimethoxytetran-butyldistannoxane complex. In the ditert-butyl series, the tritin(IV) complex isolated upon recycling features the steric effect of bulky tBu ancillary ligands. In…
Optimising training adaptations and performance in military environment.
2018
Abstract Objectives Worldwide decreases in physical fitness and increases in body fat among youth have set challenges for armed forces to recruit physically capable soldiers. Therefore, knowledge of optimizing physical adaptation and performance through physical training is vital. In addition, maintaining or improving physical performance among professional soldiers in various military environments is crucial for overall military readiness. The present review focuses on the effects of military training on physical performance by searching for optimal methods to do it. Design and methods Review article based on selected literature searches using the main keywords ‘physical performance’ and ‘…
IMPROVED PRODUCTION OF THE ANTIBIOTIC ACTINORHODIN IN STREPTOMYCES COELICOLOR IMMOBILIZED-MYCELIAL CELL CULTIVATIONS
2017
Objectives i) Evaluation of ACT production in Streptomyces coelicolor M145 mycelial cells immobilized on polycaprolactone (PCL) and polylactic acid (PLA) nanofiber membranes, modified or not by an O2- plasma treatment. ii) Identification of gene products associated with the improvement of ACT production.
Spatio-temporal changes in degassing behavior at Stromboli volcano derived from two co-exposed SO2 camera stations
2022
Improving volcanic gas monitoring techniques is central to better understanding open-vent, persistently degassing volcanoes. SO2 cameras are increasingly used in volcanic gas studies, but observations are commonly limited to one single camera alone viewing the volcanic plume from a specific viewing direction. Here, we report on high frequency (0.5 Hz) systematic measurements of the SO2 flux at Stromboli, covering a 1-year long observation period (June 2017-June 2018), obtained from two permanent SO2 cameras using the same automated algorithm, but imaging the plume from two different viewing directions. Our aim is to experimentally validate the robustness of automatic SO2 camera for volcano …
Changes in SO2 flux degassing regime prior to the 2014 Stromboli eruption
2015
Volcanic eruptions are often accompanied by release of huge amounts of magmatic SO2. Capturing sizeable precursory SO2 flux variations prior to eruption has revealed far more challenging, instead, in spite of the recent progresses in instrumental gas monitoring. Here, we report on the SO2 fluxes variations we detected at Stromboli volcano prior to the effusive eruption started on the 6th August 2014. The SO2 fluxes were regularly quantified at high-rate (0.5 Hz) using two fully autonomous permanent SO2 camera devices installed - within the framework the ERC-FP7 project "Bridge"- at two sites located at 0.5 km (Roccette) and 1.75 km (Sciara del Fuoco rim) distance from the crater terrace. Th…
The staining effect of different mouthwashes containing nanoparticles on dental enamel
2015
Background: This study aimed to evaluate the effects of several mouthwashes containing nanoparticles on discoloration of dental enamel, and compare the results with that of 0.2% chlorhexidine (CHX). Material and Methods: Sixty intact premolars were randomly assigned to six groups. A spectrophotometer was used to measure the color of the teeth (T1) according to the CIELAB system. The specimens in groups 1 to 4 were then immersed in colloidal solutions containing nanoTiO2 (Group 1), nanoZnO (Group 2), nanoAg (Group 3) and nanoCuO (Group 4). In groups 5 and 6, a 0.2% CHX mouthwash and distilled water were used as positive and negative controls, respectively. After 24 hours of immersion, color …
Electrochemical reduction of carbon dioxide to formic acid at a tin cathode in divided and undivided cells: effect of carbon dioxide pressure and oth…
2016
Abstract The reduction of carbon dioxide to formic acid at a tin cathode was studied in both divided and undivided cells. In the first stage of the study, the effect of some operating parameters, including the working potential and the nature of the supporting electrolyte and of the cathode, on both the cathodic reduction of CO2 and the anodic oxidation of formic acid was investigated in a divided cell. In a second stage, the reduction of carbon dioxide was performed in an undivided cell with the aim of studying the effect on the generation of formic acid of various operating parameters such as current density, cathode to anode area ratio, mixing rate and nature of the anode and of the supp…
The instability of the adjusted and unadjusted environmental Kuznets curves
2006
We test the stability of the unadjusted and adjusted environmental Kuznets curves (EKCs). Our results provide evidence in favour of a theoretically funded "adjusted EKC hypothesis" in which the impact of per capita GDP on CO2 emissions is evaluated conditionally to the effects of the industry mix and of the energy-supply infrastructure. In this specification, the shape of the GDP-CO2 relationship appears quite sensitive to changes in the estimation period. In the final part of the paper, signs and dynamics of fixed effects of individual countries in different specifications are interpreted as measures of virtuous or vicious of environmental behaviour. © 2006 Elsevier B.V. All rights reserve…
Non-volatile memory characteristics of a Ti/HfO2/Pt synaptic device with a crossbar array structure
2022
The resistive switching and synaptic behavior of a fabricated Ti/HfO2/Pt crossbar array device are investigated. The results demonstrated that TiOx layers are created by the movement of oxygen ions during the positive SET process, thereby improving the endurance and multilevel switching behavior of the device. The random properties of SET process were described with the help of stochastic model of memristor based on the length of conductive filament. The analysis of the mean first passage time allows estimating the parameters of the dielectric switching layer such as the activation energy of the diffusive defects, its variation under the influence of the driving voltage and the value of the…
Performance of EasyBreath® Decathlon Snorkeling mask for Delivering Continuous Positive Airway Pressure
2020
ABSTRACTBackgroundDuring the COVID-19 pandemic, the need for noninvasive respiratory support devices has dramatically increased, sometimes exceeding hospital capacity. The full-face Decathlon snorkeling mask, EasyBreath® (EB® mask), has been adapted to deliver continuous positive airway pressure (CPAP) as an emergency respiratory interface. We aimed to assess the performance of this modified EB® mask.MethodsCPAP set at 5, 10, and 15 cmH2O was delivered to 10 healthy volunteers with a high-flow system generator set at 40, 80, and 120 L min-1 and with a turbine-driven ventilator during both spontaneous and loaded (resistor) breathing. Inspiratory CO2 partial pressure (PiCO2), pressure inside …