Search results for "O2"

Laser Ablation of Poly(lactic acid) Sheets for the Rapid Prototyping of Sustainable, Single-Use, Disposable Medical Microcomponents

2018

The employment of single-use, disposable medical equipment has increased the amount of medical waste produced and the advent of point-of-care diagnostics in lab-on-chip format is likely to add further volume. Current materials used for the manufacture of these devices are derived from petroleum sources and are, therefore, unsustainable. In addition, disposal of these plastics necessitates combustion to reduce infection risk, which has, depending on material composition, an undesirable environmental impact. To address these issues, we have developed a general approach for the rapid prototyping of single-use point-of-care cartridges prepared from poly(lactic acid), a sustainable material whic…

Zirconium–hafnium and rare earth element signatures discriminating the effect of atmospheric fallout from hydrothermal input in volcanic lake water

2016

The geochemical behaviour of Rare Earth Elements, Zr and Hf was investigated in the thermal waters of Nevado del Ruiz volcano system. A wide range of pH, between 1.0 and 8.8, characterizes these fluids. The acidicwaters are sulphate dominatedwith different Cl/SO4 ratios. The important role of the pH and the ionic complexes for the distribution of REE, Zr a nd Hf in the aqueous phase was evidenced. The pH rules the precipitation of authigenic Fe and Al oxyhydroxides producing changes in REE, Zr, Hf amounts and strong anomalies of Cerium. The precipitation of alunite and jarosite removes LREE from the solution, changing the REE distribution in acidic waters. Y-Ho and Zr-Hf (twin pairs) have a…

Visible-light-induced oxidation of trans-ferulic acid by TiO2 photocatalysis

2012

Abstract The oxidation of trans-ferulic acid (C10H10O4) in aqueous TiO2 dispersion occurs via the formation of a charge-transfer complex on the TiO2 surface that is able to absorb visible light (λ ⩾ 400 nm). The main product is CO2, whereas secondary oxidation products are organic species such as vanillin, caffeic acid, homovanillic acid, and vanillylmandelic acid. Oxidation through the formation of a charge-transfer complex occurs only in the presence of specific TiO2 samples. Experiments in the absence of oxygen, in the presence of bromate ions and by using a phosphate-modified TiO2, have been carried out for investigating the reaction mechanism. In order to study the interaction between …

Photocatalytic CO2 Reduction in Gas-Solid Regime in the Presence of Bare, SiO2 Supported or Cu-Loaded TiO2 Samples

2013

Both commercial and home prepared (HP) TiO2 samples have been tested for the photocatalytic reduction of CO2. (HP) TiO2 powders were prepared by using TiCl4 or Ti(OC4H9)4 as the precursors to obtain HP1 and HP2 samples, respectively. Also HP Cu-loaded and SiO2 supported TiO2 powders were prepared. The HP samples were more active than the commercial ones for the photoreduction of CO2 with and without water vapour. HP1 produced mainly formaldehyde, HP2 principally methane. Acetaldehyde was found to be the primary product obtained when HP1 was supported on SiO2. The addition of Cu increased the photocatalytic reactivity either of bulk and SiO2-supported HP1. In particular, 1 wt % of Cu improve…

Recent advances in ground based ultraviolet remote sensing of volcanic SO2 fluxes

2011

Überprüfung der Präzision von Kapnometern

1992

Capnometry, i.e. measurement of CO2 concentration (cCO2, vol%) and calculation of the respective CO2 partial pressure (pCO2, mmHg), is simple to apply, but the user must understand its principles of operation in order to appreciate its power and its limitations. However, sidestream capnometers use to dry the humidified respired gas (37 degrees C, pH2O 47 mmHg) for methodological reasons, thus increasing pCO2 by ca. 6% which, in turn, requires correction. With infrared spectroscopy, overestimation of pCO2 in presence of N2O and underreporting of pCO2 in presence of O2 also require to be corrected. These require either knowledge of the respective gas concentrations (mainstream analyzers) or a…

Riduzione Fotocatalitica di CO2 in Presenza di Catalizzatori Compositi GaP/TiO2

2014

Highly textured boron/nitrogen co-doped TiO2 with honeycomb structure showing enhanced visible-light photoelectrocatalytic activity

2020

International audience; In this work, we report a novel photocatalyst based on boron and nitrogen co-doped TiO2 rutile (1 1 0) honeycomb structures. The photocatalyst has been prepared by simultaneously oxidizing and doping a Ti-foil substrate at 750 degrees C. The unit cell volume and the crystallite size of grown TiO2 films were measured by Rietveld refinement analysis. The co-doping by boron and nitrogen was achieved simultaneously with the oxidation of the titanium, resulting in a rutile (1 1 0) textured TiO2 film. X-ray photoelectron spectroscopy analysis revealed the presence of Ti-O-N and Ti-O-B-N bonds, and the presence of crystal defects in the lattice was detected and displayed by…

Diversité des Brettanomyces et de leur résistance au SO2. Les nouvelles avancées vers une meilleure gestion du SO2 en vinification.

2019

International audience; Des recherches ont été menées par le Groupe National « Lutte contre Brettanomyces » et plus particulièrement sur la relation SO2 et Brettanomyces bruxellensis afin d’approfondir les connaissances sur le comportement de la levure et d’apporter des données essentielles à une bonne gestion du risque.Une grande diversité de la levure Brettanomyces a été mise en évidence (identification de différents groupes génétiques) ainsi que des comportements différents vis-à-vis du SO2 : sensibles, tolérants ou résistant. Grâce à la mise au point d’un outil prédictif (TYP \ Brett), les professionnels pourront connaître le groupe génétique pour mieux intervenir.Ces travaux ont égalem…

High-Resolution Photoacoustic Raman-Spectroscopy of Gases

1992

0377-0486; A high-resolution photoacoustic Raman spectroscopy experiment is described. The resolution achieved by using two single-mode pulsed lasers is about 0.0054 cm-1 (full width at half maximum intensity). The experiment was tested first on the v1/2v2 bands of CO2 and gave an increase of at least about one order of magnitude in the signal-to-noise ratio with respect to stimulated Raman spectroscopy at low pressure (ca. 10 Torr almost-equal-to 13 kPa). The sensitivity is also demonstrated by the study of the weak hot band v1 + v2 - v2 of CO2. In both cases, the experimental line shape is well reproduced by taking into account Doppler and collisional effects. A comparison with CARS spect…