Search results for "CO2"

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

2014

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…

Determination of Temperature by Stimulated Raman Scattering of Molecular Nitrogen, Oxygen, and Carbon-Dioxide

1993

0721-7269; We have determined the temperature from SRS spectra of N2-N2, N2-CO2, O2-O2, and CO2-CO2 recorded in wide pressure and temperature ranges. The fitting procedure takes simultaneously into account the Dicke effect and motional narrowing. We have quantified the accuracy of the MEG and ECS-P models for rotational relaxation. The temperature extracted from each model is compared with thermocouple measurements. The influence of vibrational broadening and shifting is discussed in detail.

Adsorptive Separation of CO2 by a Hydrophobic Carborane-Based Metal-Organic Framework under Humid Conditions

2023

We report that the carborane-based metal-organic framework (MOF) mCB-MOF-1 can achieve high adsorptive selectivity for CO2:N2 mixtures. This hydrophobic MOF presenting open metal sites shows high CO2 adsorption capacity and remarkable selectivity values that are maintained even under extremely humid conditions. The comparison of mCB-MOF-1' with MOF-74(Ni) demonstrates the superior performance of the former under challenging moisture operation conditions.

UN MODELLO EMPIRICO DI EMISSIONE DI CO2 DAL SUOLO: CURVE DI RISPOSTA ALLA TEMPERATURA ED ALL'UMIDITÀ DEL SUOLO DI UN AGROECOSISTEMA MEDITERRANEO

2012

Il presente lavoro è stato condotto su suolo prelevato all’interno di un oliveto con l’obiettivo di valutare il tasso di respirazione attribuibile alla componente eterotrofa (microbica) in funzione dei fattori temperatura ed umidità. Il tasso di respirazione è stato monitorato su suolo incubato a cinque livelli di temperatura, 10-15-20-25-30 °C e a quattro livelli del contenuto idrico volumetrico del suolo (θ) 12,6-18,9-25,2-31,5 % (v/v). I valori di respirazione hanno presentato un range di valori variabili tra 78,20 e 14,81 µg CO2 g-1 soil d-1 rispettivamente a 30°C e 10°C e a 12,6 e 31,5 %. I valori di Q10, ovvero la risposta della respirazione in relazione agli incrementi di temperatura…

Fruit productivity and carbon gain of Opuntia ficus-indica (L.) Mill. trees

2012

Opuntia ficus-indica (OFI) tree and orchards efficiency has been poorly studied, in terms of relation between orchard lay out, light interception, and cropping efficiency. Apparently, there is no other way to increase orchard production than increasing the number either of trees ha-1 or fertile shoots tree-1, considering that a fruit count higher than 6-7 cladode-1 reduces fruit harvest size. The first option requires a reduction of unit tree size and canopy volume. The second option implies the use of large trees that often reduce their efficiency 12-15 years after planting. In 15-year-old OFI trees spaced 6 5 m apart trained to a globe and 2.5-3.0 m high, stem area index (SAI) calculated …

The duality of ocean acidification as a resource and a stressor

2018

Ecologically dominant species often define ecosystem states, but as human disturbances intensify, their subordinate counterparts increasingly displace them. We consider the duality of disturbance by examining how environmental drivers can simultaneously act as a stressor to dominant species and as a resource to subordinates. Using a model ecosystem, we demonstrate that CO2-driven interactions between species can account for such reversals in dominance; i.e., the displacement of dominants (kelp forests) by subordinates (turf algae). We established that CO2 enrichment had a direct positive effect on productivity of turfs, but a negligible effect on kelp. CO2 enrichment further suppressed the …

Effects of ocean acidification on the shells of four Mediterranean gastropod species near a CO2 seep

2017

Marine CO2seeps allow the study of the long-term effects of elevated pCO2(ocean acidification) on marine invertebrate biomineralization. We investigated the effects of ocean acidification on shell composition and structure in four ecologically important species of Mediterranean gastropods (two limpets, a top-shell snail, and a whelk). Individuals were sampled from three sites near a volcanic CO2seep off Vulcano Island, Italy. The three sites represented ambient (8.15 pH), moderate (8.03 pH) and low (7.73 pH) seawater mean pH. Shell mineralogy, microstructure, and mechanical strength were examined in all four species. We found that the calcite/aragonite ratio could vary and increased signifi…

Ocean acidification as a driver of community simplification via the collapse of higher-order and rise of lower-order consumers

2017

AbstractIncreasing oceanic uptake of CO2 is predicted to drive ecological change as both a resource (i.e. CO2 enrichment on primary producers) and stressor (i.e. lower pH on consumers). We use the natural ecological complexity of a CO2 vent (i.e. a seagrass system) to assess the potential validity of conceptual models developed from laboratory and mesocosm research. Our observations suggest that the stressor-effect of CO2 enrichment combined with its resource-effect drives simplified food web structure of lower trophic diversity and shorter length. The transfer of CO2 enrichment from plants to herbivores through consumption (apparent resource-effect) was not compensated by predation, becaus…

Are control of extracellular acid-base balance and regulation of skeleton genes linked to resistance to ocean acidification in adult sea urchins?

2020

SCOPUS: ar.j