Search results for "carbon"
showing 10 items of 6057 documents
Fracture stratigraphy of Mesozoic platform carbonates, Agri Valley, southern Italy
2022
The outcropping platform carbonates form a layered succession crosscut by a dense array of bed-parallel pressure solution seams and veins, oblique-to-bedding pressure solution seams, and high-angle joints, veins, and pressure solution seams. Altogether, these structural elements form sub-seismic heterogeneities that formed during the polyphase tectonic evolution of the southern Apennines fold and-thrust belt, Italy. Aiming at assessing the role exerted by the primary carbonate architecture on failure modes and fracture geometry and distribution, we conduct a multi-disciplinary study by performing stratigraphic, petrographic, mineralogical, and mesoscale structural analyses. Based on carbona…
Modeling biomass char gasification kinetics for improving prediction of carbon conversion in a fluidized bed gasifier
2014
Gasification of biomass in a fluidized bed (FB) was modeled based on kinetic data obtained from previously conducted thermo- gravimetic analysis. The thermogravimetric analysis experiments were designed to closely resemble conditions in a real FB gasifier by using high sample heating rates, in situ devolatilization and gas atmospheres of H 2 O / H 2 and CO 2 / CO mixtures. Several char kinetic models were evaluated based on their ability to predict char conversion based on the thermogravimetric data. A modified version of the random pore model was shown to provide good fitting of the char reactivity and suitability for use in a reactor model. An updated FB reactor model which incorporates t…
Radiocarbono y neolitización en la Península Ibérica
2016
En este trabajo hemos llevado a cabo una recopilación de las dataciones radiocarbónicas disponibles para el conjunto de la Península Ibérica con el objetivo de construir mapas temporales del desarrollo del proceso de neolitización. Hemos representado de este modo la densidad de las dataciones radiocarbónicas calibradas espacialmente, lo cual permite realizar una lectura diacrónica sobre las dinámicas poblacionales de los últimos caza-recolectores y los primeros agricultores y ganaderos. La asunción de partida consiste en considerar el conjunto de las dataciones como una muestra casi aleatoria para indagar sobre la evolución del poblamiento peninsular. En la bibliografía reciente se han seña…
Natural acidification changes the timing and rate of succession, alters community structure, and increases homogeneity in marine biofouling communiti…
2017
Ocean acidification may have far-reaching consequences for marine community and ecosystem dynamics, but its full impacts remain poorly understood due to the difficulty of manipulating pCO2 at the ecosystem level to mimic realistic fluctuations that occur on a number of different timescales. It is especially unclear how quickly communities at various stages of development respond to intermediate-scale pCO2 change and, if high pCO2 is relieved mid-succession, whether past acidification effects persist, are reversed by alleviation of pCO2 stress, or are worsened by departures from prior high pCO2 conditions to which organisms had acclimatized. Here, we used reciprocal transplant experiments al…
Self-Complementary Dimers of Oxalamide-Functionalized Resorcinarene Tetrabenzoxazines
2018
Self‐complementarity is a useful concept in supramolecular chemistry, molecular biology and polymeric systems. Two resorcinarene tetrabenzoxazines decorated with four oxalamide groups were synthesized and characterized. The oxalamide groups possessed self‐complementary hydrogen bonding sites between the carbonyls and amide groups. The self‐complementary nature of the oxalamide groups resulted in self‐included dimeric assemblies. The hydrogen bonding interactions within the tetrabenzoxazines gave rise to the formation of dimers, which were confirmed by single‐crystal X‐ray diffractions analysis and supported by NMR spectroscopy and mass spectrometry. The self‐included dimers were connected b…
Statistique de l'efficacité de blindage de matériaux composites pour la 5G: méthodes avancées d'échantillonnage
2020
International audience; Cette proposition présente une méthodologie pour l'estimation statistique du niveau de protection offert par des matériaux composites constitués par des fibres de carbone sur une large gamme de fréquences contenant la bande 5G. La variabilité géométrique des nanostructures de carbone (essentiellement en termes de formes et de dimensions) impose, dans un premier temps, une caractérisation fréquentielle précise de la distribution statistique des propriétés diélectriques des matériaux. La propagation, dans un second temps, des incertitudes précédentes au niveau de l'efficacité de blindage des matériaux apporte des contraintes particulières quand aux méthodes statistique…
Effect of Stacking Sequence and Sodium Bicarbonate Treatment on Quasi-Static and Dynamic Mechanical Properties of Flax/Jute Epoxy-Based Composites
2019
The present paper deals with the investigation of quasi-static and dynamic mechanical response of epoxy-based composites reinforced with flax and/or jute plain weave fabrics. In order to evaluate the influence of the stacking sequence, two monolithic laminates reinforced with flax or jute fibers and two hybrid flax/jute laminates were manufactured through the vacuum infusion technique. Furthermore, an eco-friendly and cost-effective surface treatment based on fiber soaking in a sodium bicarbonate solution was employed to improve the fiber-matrix adhesion. The mechanical characterization (by means of quasi-static flexural, dynamic mechanical thermal analysis and Charpy impact tests) allowed …
The influence of bacteria-dominated diets on Daphnia magna somatic growth, reproduction, and lipid composition
2012
We explored how dietary bacteria affect the life history traits and biochemical composition of Daphnia magna, using three bacteria taxa with very different lipid composition. Our objectives were to (1) examine whether and how bacteria-dominated diets affect Daphnia survival, growth, and fecundity, (2) see whether bacteria-specific fatty acid (FA) biomarkers accrued in Daphnia lipids, and (3) explore the quantitative relationship between bacteria availability in Daphnia diets and the amounts of bacterial FA in their lipids. Daphnia were fed monospecific and mixed diets of heterotrophic (Micrococcus luteus) or methanotrophic bacteria (Methylomonas methanica and Methylosinus trichosporium) and…
Actual provision as an alternative criterion to improve the efficiency of payments for ecosystem services for C sequestration in semiarid vineyards
2016
The aim of this paper is to evaluate the efficiency of the PES scheme actually used in the Sicilian rural development program, based on an egalitarian criterion, and proposing an alternative scheme in order to guarantee a greater equity and fairness of premium distribution in relation to soil carbon (C) sequestration potential. We, first, assessed the ecosystem services (ES) provided by agri-environmental measures (AEM) in terms of SOC stock increase in Sicilian vineyards. Based on these data we evaluated the efficiency of agro-environmental payments according to an egalitarian criterion and simulated the effects of the actual provision criterion adoption. Results showed that the adoption o…
Pancreatic islets from non-heart beating donor pig: Two-layer preservation method in an in vitro porcine model
2011
Purpose Pancreata from non-heart beating donors could represent an unlimited source of islets if their cell viability can be efficiently preserved during the time necessary to process the organs by the use of a better solution of preservation compared to the classic University of Wisconsin solution. The aim of this study was to determine whether it is possible to obtain functioning “alive islets” from non-heart-beating donors by comparing, on a porcine model, the classic “UW ice-store” method with a two-layer cold storage method (TLM) using oxygenated Perfluorocarbons (PFC) and UW. Methods Whole pancreata were harvested from 20 NHBDs female pigs with similar characteristics and preserved fo…