Search results for "CO2"

Phthalocyanines-TiO2: A New Efficient and Tunable Catalyst for CO2 Reduction in Water

2014

On the half-metallicity of Co2FeSi Heusler alloy: Point-contact Andreev reflection spectroscopy andab initiostudy

2013

Co2FeSi, a Heusler alloy with the highest magnetic moment per unit cell and the highest Curie temperature, has largely been described theoretically as a half-metal. This conclusion, however, disagrees with point contact Andreev reflection (PCAR) spectroscopy measurements, which give much lower values of spin polarization, P. Here, we present the spin polarization measurements of Co2FeSi by the PCAR technique, along with a thorough computational exploration, within the DFT and a GGA+U approach, of the Coulomb exchange U parameters for Co and Fe atoms, taking into account spin-orbit coupling. We find that the orbital contribution (mo) to the total magnetic moment (mT) is significant, since it…

Postpulse molecular alignment measured by a weak field polarization technique

2003

We report a direct nonintrusive observation of alignment and planar delocalization of ${\mathrm{C}\mathrm{O}}_{2}$ after an intense linearly polarized femtosecond laser pulse excitation. The effects are measured by a polarization technique involving a perturbative probe that itself does not induce appreciable alignment. We show that this technique allows one to measure a signal proportional to $⟨{cos}^{2}\ensuremath{\theta}⟩\ensuremath{-}1/3$, with $\ensuremath{\theta}$ the angle between the molecular axis and the laser polarization. Simulations that support this analysis allow one to characterize the experimentally observed alignment and planar delocalization quantitatively.

Electrochemical conversion of carbon dioxide in pressurized electrochemical cells

2019

To limit the negative effect of carbon dioxide as a greenhouse gas, an interesting approach is the utilization of Carbon Capture and Conversion (CCC) methodology, which is focused on the use of CO2 waste as a feedstock to produce added-value products by using the excess electric energy from renewable source [1]. In this framework, an increasing attention has been devoted to the electrochemical conversion of carbon dioxide to formic acid in water [2-3] or CO [1]. Since the main hurdle of the CO2 reduction from aqueous solution is the low CO2 solubility in water, in this work, the utilization of pressurized electrochemical cells is evaluated. The effect of various operating parameters, includ…

Diffuse degassing of carbon dioxide at Somma-Vesuvius volcanic complex (Southern Italy) and its relation with regional tectonics

2004

Abstract A systematic survey of soil CO 2 concentrations was carried out on the flanks of Somma–Vesuvius volcano in order to constrain possible pathways responsible of carbon dioxide diffuse degassing taking place during the present state of quiescence. Measurements were performed at 1162 sites in late winter–spring 2000, highlighting that soil CO 2 concentrations range from 50 to 10500 ppmV. A statistical analysis was developed in order to define the threshold value of anomaly and separate the biogenic CO 2 component, produced by soil respiration, from the inorganic component of deep provenance. A computer routine was also elaborated to interpret the grid of CO 2 anomalous concentration va…

The Impact of the Poland Foreign Trade On Its Real CO2 Emissions

2017

CO2 emissions are a global problem. This means that nothing or very little will change if only particular countries are involved. The purpose of this paper is the attempt to show the real CO2 emissions of the Poland as well as the impact of its trade on CO2 emissions in other countries in the world and in the EU in 2015. This study was conducted on the group of countries that are the major emitters of CO2 in the world including most of the EU members. Actual CO2 emissions were achieved by applying the actual emission factor. This takes into account the transfer of CO2 in export products and services as well as those imported by particular countries. It has turned out that the real CO2 emiss…

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…

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…

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…