Search results for "CO2"

Carbon degassing through karst hydrosystems of Greece

2022

Estimation of CO2 degassing from active tectonic structures and regional hydrothermal systems is essential for the quantification of presentday Earth degassing [Frondini et al., 2019 and references therein]. Due to the high solubility of CO2 in water, great amounts of deep inorganic carbon can be dissolved, transported, and released from regional aquifers. By applying a massbalance approach [Chiodini et al., 2000], different sources of the dissolved CO2 can be discriminated. The main source of degassing in Greece is concentrated in hydrothermal and volcanic areas. However, deep CO2 from active tectonic areas has not yet been quantified. A key point of this research is to investigate the pos…

Ein Extrapolationsverfahren zur unblutigen Bestimmung des O2-und CO2-Partialdruckes im ven�sen Mischblut

1969

Es wird eine neue Methode zur unblutigen Messung des O2-und des CO2-Partialdruckes im venosen Mischblut beschrieben. Dabei inspiriert der Proband zunachst ein Atemzugvolumen eines Gasgemisches mit 10–13 Vol-% CO2 und dem Rest N2. Am Ende der folgenden Exspiration wird vom offenen auf ein geschlossenes respiratorisches System umgeschaltet, dessen Ruckatmungsbeutel anfanglich 1,5–2,5 l eines Gemisches von 5,5–7,5 Vol-% CO2 und N2 als Rest enthalt. Eine schnellregistrierende Platinelektrode und ein Ultrarotabsorptionsschreiber analysieren fortlaufend die respiratorischen O2-und CO2-Partialdruckanderungen am Mundstuck des Probanden. Die Umhullenden der wahrend der Ruckatmung aufgezeichneten Kur…

Principles and method for H2 and CO2 monitoring in volcanic areas: preliminary results for Stromboli and Etna volcanoes

2011

Alignement moléculaire : caractérisation et application à la mesure de thermalisation ultra-rapide et au contrôle de génération d'harmoniques

2013

The thematic of this thesis is molecular alignment. The latter is a very important topic that opens the way toward a much more thin control of many phenomenons. So, we have developed a new measurement technique of the molecular alignment along one axis that permits to preserve the sign of alignment. This one is, like other measurement techniques developed by the team,based on the measurement of the refractive index variation induced by the molecular alignment.The technique developed then also permits the molecular alignment measurement, being also an application of it because it allows the third harmonic generation. In the last study, molecular alignment is implemented to show that it bring…

Sostenibilidad empresarial y estrategias de divulgación de huella de carbono

2021

El cambio climático es uno de los mayores desafíos medioambientales en los actuales momentos, su creciente aceptación como una de las cuestiones más urgentes en el mundo, a nivel social, político y empresarial ha llevado a las organizaciones a introducir mecanismos de control y mitigación ambiental como parte de sus compromisos adquiridos, siendo uno de ellos la divulgación sobre emisiones de carbono. En este sentido, el sector empresarial, como ente dinamizador de las economías de todo el mundo, es uno de los principales agentes en la lucha contra el cambio climático; por otro lado, a pesar del aumento de la divulgación de GEI, hay aún evidencias relativamente escasas en la literatura de l…

Dried-Fruit Storage: An Analysis of Package Headspace Atmosphere Changes

2019

The quality of packaged dried foods depends on storage conditions and is determined largely by the initial gas composition inside and the transference through the container. The aim of this work was to analyze the O2 and CO2 concentrations within the internal atmosphere of the packaging. In this study, dried apricots and raisins were packaged in glass jars and polypropylene trays thermosealed with different polymers, and stored at 5, 15, 25, and 35 &deg

Reconsidering TOF calculation in the transformation of epoxides and CO2 into cyclic carbonates

2020

Abstract The combination of Lewis acids and Lewis bases, currently defined as catalysts and co-catalysts (or promoter) respectively, in the reaction between epoxides and CO2 to give cyclic carbonates, is discussed, starting from examples in which the Lewis base was used in larger amount with respect to the Lewis acid. In these cases, turnover frequency (TOF) values have been usually calculated taking into account solely the amount of the Lewis acid employed. The occurrence of two distinct reaction pathways, one catalysed by the sole Lewis base and the other one catalysed by the Lewis acid/Lewis base couple, in which the Lewis acid alone does not play a catalytic role, should bring researche…

Electrochemical conversion of CO2 to formic acid using a Sn based cathode: Combined effect of temperature and pressure

2023

Electrochemical conversion of CO2 in the aqueous electrolyte into value-added chemicals is considered one of the most promising strategies to valorize waste-CO2. In the last decade, high attention was focused on the electro- chemical synthesis of formic acid (FA) via CO2 reduction using Sn cathodes. To improve the final concentration of FA in aqueous electrolytes, several approaches, including the utilization of different technologies (i.e. pressurized CO2 reactor, a gas diffusion electrode, divided cell etc...) and different operative conditions (i.e. pH, current densities, temperature, mixing rate, etc...) were investigated in detail. To date, the effect of temperature (T) on the electroc…

Ocean acidification and elevated temperature negatively affect recruitment, oxygen consumption and calcification of the reef-building Dendropoma cris…

2019

Expected temperature rise and seawater pH decrease may affect marine organism fitness. By a transplant experiment involving air-temperature manipulation along a natural CO2 gradient, we investigated the effects of high pCO(2) (similar to 1100 mu atm) and elevated temperature (up to +2 degrees C than ambient conditions) on the reproductive success, recruitment, growth, shell chemical composition and oxygen consumption of the early life stages of the intertidal reef-building vermetid Dendropoma cristatum. Reproductive success was predominantly affected by temperature increase, with encapsulated embryos exhibiting higher survival in control than elevated temperature conditions, which were in t…

Effects of soil gas permeability and recirculation flux on soil CO2 flux measurements performed using a closed dynamic accumulation chamber

2009

Abstract Dynamic accumulation chamber methods have been extensively used to estimate the total output of CO2 released from active volcanic area. In order to asses the performance and reliability of a closed dynamic system several tests were carried out with different soil permeabilities and soil CO2 fluxes. A special device was used to create a constant one-dimensional CO2 flux through a soil column with a known permeability. Three permeabilities were investigated, ranging between 3.6 × 10− 2 and 3.5 × 10 μm2, as were several CO2 fluxes (ranging between 1.1 × 10− 6 and 6.3 × 10− 5 kg m− 2 s− 1). The results highlight that the accuracy of soil CO2 flux measurements strictly depends on the so…