Literatura académica sobre el tema "Carbonate pump"
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Artículos de revistas sobre el tema "Carbonate pump"
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Silkin, Vladimir A., Oleg I. Podymov y Anna V. Lifanchuk. "Biological carbon pump in the Black Sea". Hydrosphere Еcology (Экология гидросферы), n.º 2(8) (diciembre de 2022): 69–92. http://dx.doi.org/10.33624/2587-9367-2022-2(8)-69-92.
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In the northeastern part of the Black Sea, the biological carbon pump is represented by both organic and carbonate pumps. The organic carbon pump consists of small-cell diatoms (mainly Pseudo-nitzschia pseudodelicatissima) and large-cell diatoms (Pseudosolenia calcar-avis and Proboscia alata). The carbonate pump is represented by only one species of cococcolithophore, Emiliania huxleyi. These species form intense blooms that require characteristic hydrological and hydrochemical conditions. The seasonal dynamics of the biological carbon pump is as follows: organic pump (spring) → carbonate pump (late spring and early summer) → organic pump (summer and autumn). An exception is the long-term dynamics of carbon concentration, and no significant carbon growth trends have been identified. During the intensification of the work of the carbonate pump, partial concentrations of carbon in water, increased relative to the atmosphere, and an increased influence of the organic pump on high partial pressure are released. In late spring and early summer, CO2 is released in the Black Sea, as a result, absorption increases in summer. The carbonate pump arises with a greater arrival at sea.
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Pautova, Larisa A. y Vladimir A. Silkin. "Biological carbon pump in the ocean and phytoplankton structure". Hydrosphere Еcology (Экология гидросферы), n.º 1(3) (2019): 1–12. http://dx.doi.org/10.33624/2587-9367-2019-1(3)-1-12.
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The process of carbon transfer from the atmosphere to the ocean floor is determined by three different pumps in nature: a solubility pump, an organic pump and a carbonate pump. The latter two are of biological nature. Phytoplankton is a key mediator of organic and carbonate pumps. Depending on its structure, either an organic pump or a carbonate pump will dominate. The structure of the phytoplankton community is formed depending on the hydrophysical and hydrochemical conditions in the ocean. An important regulator of a biological carbon pump is the intensity of the processes in the carbon cycle, operating in the photic zone. The degree of closure of this cycle depends on the structure of the food chain. The increasing complexity of the food chain by adding organisms of high trophic levels reduces the efficiency of the carbon pump. Conversely, the simplification of such a structure increases the flow of organic carbon to the ocean floor.
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J.P, GUPTA, SUMBRIA N.M y KHANNA Y.P. "QUALITY OF DIFFERENT SOURCES OF IRRIGATION WATER OF JAMMU REGION". Madras Agricultural Journal 85, February (1998): 110–12. http://dx.doi.org/10.29321/maj.10.a00694.
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Water samples from different sources viz., rivers, streams, nallahs, tube wells and hand pumps in Jammu region were collected and analysed for quality parameters to ascertain their suitability for imigation purposes. Except some of the tubewell and hand pump water samples which showed higher values of residual sodium carbonate, most of the water sources were observed to he suitable for irrigation purposes.
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Cerclet, Léo, Benoît Courcelles y Philippe Pasquier. "Impact of Standing Column Well Operation on Carbonate Scaling". Water 12, n.º 8 (7 de agosto de 2020): 2222. http://dx.doi.org/10.3390/w12082222.
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Standing column well constitutes a recent promising solution to provide heating or cooling and to reduce greenhouse gases emissions in urban areas. Nevertheless, scaling issues can emerge in presence of carbonates and impact their efficiency. Even though a thermo-hydro-geochemical model demonstrated the impact of the water temperature on carbonate concentration, this conclusion has not been yet demonstrated by field investigations. To do so, an experimental ground source heat pump system connected to a standing column well was operated under various conditions to collect 50 groundwater samples over a period of 267 days. These field samples were used for mineral analysis and laboratory batch experiments. The results were analyzed with multivariate regression and geochemical simulations and confirmed a clear relationship between the calcium concentrations measured in the well, the temperature and the calcite equilibrium constant. It was also found that operating a ground source heat pump system in conjunction with a small groundwater treatment system allows reduction of calcium concentration in the well, while shutting down the system leads to a quite rapid increase at a level consistent with the regional calcium concentration. Although no major clogging or biofouling problem was observed after two years of operation, mineral scales made of carbonates precipitated on a flowmeter and hindered its operation. The paper provides insight on the impact of standing column well on groundwater quality and suggests some mitigation measures.
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Guo, Liyu y Wenju Shan. "Water Source Heat Pump’s Stuck Problems and Solutions". Journal of Physics: Conference Series 2174, n.º 1 (1 de enero de 2022): 012084. http://dx.doi.org/10.1088/1742-6596/2174/1/012084.
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Abstract This paper analyses the water source heat pump’s normal stuck reasons, and test each of them. Identify the main reasons of the stuck pump is pump mechanical seal dynamic ring and static ring binding problems. (Poor water quality, water calcium carbonate, magnesium carbonate grind through the dynamic and static ring, after a long time stop, static ring long force extrusion contact, static ring binding surface molecular diffusion migration adhesion), due to the two rings’ binding, rotating torque beyond the motor starting torque, make the motor can’t start normally. This paper aims to find the real cause of the dynamic ring absorption, and put forward subsequent rectification measures to prevent recurrent stuck.
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Gao, Qing He, Yi Can Wang y Yu Mei Jiang. "Study on Scaling Formation Characteristics and Produced Liquid Properties in Oil-Wells of ASP Flooding". Advanced Materials Research 524-527 (mayo de 2012): 1270–78. http://dx.doi.org/10.4028/www.scientific.net/amr.524-527.1270.
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Strong base ASP flooding technology can improve oil recovery by 20%, but the lifting system exists serious scaling problems which cause pump detection period shorter. The main composition of the scale are organisms (heavy oil is in majority), carbonates and silicates. The content of each component is closely related to pH value. With high pH value, the main composition of the scale is silicate. With low pH value, the main composition of the scale is carbonate. The results of analysis of the relationship between scale composition, scaling position and depositional sequence showed that the content of silicate gradually increased from top to down in shaft while the carbonate decreased. In the process of scale deposition, carbonate scale emerged at first and then it provided attachment points and crystal nucleus for the silicate. The rough surface of carbonate scale increased the friction between the fluid and the wall, it promoted the formation of silicate. Statistically analyze the properties of pH value, alkalinity, calcium, magnesium, silicon, polymer, viscosity, surfactant, fluid yield, water content in produced liquid and their influences on scaling in the injection-production period. Establish the prediction basis using the pH value as primary and ion content as supplement for the problems of mechanical production well scaling. In the period of carbonate scaling (pH10.5), the process slowed down. The coincidence rate was 93.9% after pilot tests. It provided a basis for taking corresponding measures to inhibit scale formation.
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Matsumura, Yukihiko y Kunio Yoshida. "Heat pump characteristics of sodium carbonate dehydration/hydration system". International Journal of Energy Research 19, n.º 3 (abril de 1995): 253–61. http://dx.doi.org/10.1002/er.4440190309.
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Planchat, Alban, Laurent Bopp, Lester Kwiatkowski y Olivier Torres. "The carbonate pump feedback on alkalinity and the carbon cycle in the 21st century and beyond". Earth System Dynamics 15, n.º 3 (3 de mayo de 2024): 565–88. http://dx.doi.org/10.5194/esd-15-565-2024.
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Abstract. Ocean acidification is likely to impact all stages of the ocean carbonate pump, i.e. the production, export, dissolution and burial of biogenic CaCO3. However, the associated feedback on anthropogenic carbon uptake and ocean acidification has received little attention. It has previously been shown that Earth system model (ESM) carbonate pump parameterizations can affect and drive biases in the representation of ocean alkalinity, which is critical to the uptake of atmospheric carbon and provides buffering capacity towards associated acidification. In the sixth phase of the Coupled Model Intercomparison Project (CMIP6), we show divergent responses of CaCO3 export at 100 m this century, with anomalies by 2100 ranging from −74 % to +23 % under a high-emission scenario. The greatest export declines are projected by ESMs that consider pelagic CaCO3 production to depend on the local calcite/aragonite saturation state. Despite the potential effects of other processes on alkalinity, there is a robust negative correlation between anomalies in CaCO3 export and salinity-normalized surface alkalinity across the CMIP6 ensemble. Motivated by this relationship and the uncertainty in CaCO3 export projections across ESMs, we perform idealized simulations with an ocean biogeochemical model and confirm a limited impact of carbonate pump anomalies on 21st century ocean carbon uptake and acidification. However, we highlight a potentially abrupt shift, between 2100 and 2300, in the dissolution of CaCO3 from deep to subsurface waters when the global-scale mean calcite saturation state reaches about 1.23 at 500 m (likely when atmospheric CO2 reaches 900–1100 ppm). During this shift, upper ocean acidification due to anthropogenic carbon uptake induces deep ocean acidification driven by a substantial reduction in CaCO3 deep dissolution following its decreased export at depth. Although the effect of a diminished carbonate pump on global ocean carbon uptake and surface ocean acidification remains limited until 2300, it can have a large impact on regional air–sea carbon fluxes, particularly in the Southern Ocean.
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Salmon, K. H., P. Anand, P. F. Sexton y M. Conte. "Upper ocean mixing controls the seasonality of planktonic foraminifer fluxes and associated strength of the carbonate pump in the oligotrophic North Atlantic". Biogeosciences Discussions 11, n.º 8 (12 de agosto de 2014): 12223–54. http://dx.doi.org/10.5194/bgd-11-12223-2014.
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Abstract. Oligotrophic regions represent up to 75% of Earth's open-ocean environments, and are typically characterized by nutrient-limited upper-ocean mixed layers. They are thus areas of major importance in understanding the plankton community dynamics and biogeochemical fluxes. Here we present fluxes of total planktonic foraminifera and eleven planktonic foraminifer species from a bi-weekly sediment trap time series in the oligotrophic Sargasso Sea, subtropical western North Atlantic Ocean at 1500 m water depth, over two ∼2.5 year intervals, 1998–2000 and 2007–2010. Foraminifera flux was closely correlated with total mass flux and with carbonate and organic carbon fluxes. We show that the planktonic foraminifera flux increases approximately five-fold during the winter–spring, contributing up to ∼40% of the total carbonate flux, driven primarily by increased fluxes of deeper dwelling ("globorotaliid") species. Interannual variability in total foraminifera flux, and in particular fluxes of the deep dwelling Globorotalia truncatulinoides, Globorotalia hirsuta, Globorotalia inflata, were related to differences in seasonal mixed layer dynamics affecting the strength of the spring phytoplankton bloom and export flux, and by the passage of mesoscale eddies. The heavily calcified, dense carbonate tests of deeper dwelling species (3 times denser than surface dwellers) can contribute up to 90% of the foraminiferal-derived carbonate in this region during late winter-early spring, implying a high seasonality of the biological carbonate pump in oligotrophic oceanic regions. Our data suggest that climate cycles, such as the North Atlantic Oscillation, that modulate the depth of the mixed layer, intensity of nutrient upwelling and primary production could also modulate the strength of the biological carbonate pump in the oligotrophic North Atlantic.
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Guo, Yintong, Peng Deng, Chunhe Yang, Xin Chang, Lei Wang y Jun Zhou. "Experimental Investigation on Hydraulic Fracture Propagation of Carbonate Rocks under Different Fracturing Fluids". Energies 11, n.º 12 (15 de diciembre de 2018): 3502. http://dx.doi.org/10.3390/en11123502.
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Deep carbonate reservoirs are rich in oil and gas resources. However, due to poor pore connectivity and low permeability, it is necessary to adopt hydraulic fracturing technology for their development. The mechanism of hydraulic fracturing for fracture initiation and propagation in carbonate rocks remains unclear, especially with regard to selection of the type of fracturing fluid and the fracturing parameters. In this article, an experimental study focusing on the mechanisms of hydraulic fracturing fracture initiation and propagation is discussed. Several factors were studied, including the type of injecting fracturing fluids, pump flow rate, fracturing pressure curve characteristics, and fracture morphology. The results showed the following: (1) The viscosity of fracturing fluid had a significant effect on fracturing breakdown pressure. Under the same pump flow rate, the fracturing breakdown pressure of slick water was the lowest. Fracturing fluids with low viscosity could easily activate weakly natural fractures or filled fractures, leading to open microcracks, and could effectively reduce the fracturing breakdown pressure. (2) The fluctuations in fracturing pump pressure corresponded with the acoustic emission hits and changes in radial strain; for every drop of fracturing pressure, acoustic emission hits and changes in radial strain were mutated. (3) Under the same fracturing fluid, the pump flow rate mainly affected fracturing breakdown pressure and had little effect on fracture morphology. (4) The width of the main fracture was affected by the viscosity and pump flow rate. Maximum changes in radial strain at the fracturing breakdown pressure point occurred when the fracturing fluid was guar gum. (5) With gelled acid and cross-linked acid fracturing, the main fractures were observed on the surface. The extension of the fracturing crack was mainly focused near the crack initiation parts. The crack expanded asymmetrically; the wormhole was dissolved to break through to the surface of the specimen. (6) The dissolution of gelled acid solution could increase the width of the fracturing crack and improve the conductivity of carbonate reservoirs.
Tesis sobre el tema "Carbonate pump"
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Planchat, Alban. "Alkalinity and calcium carbonate in Earth system models, and implications for the ocean carbon cycle". Electronic Thesis or Diss., Université Paris sciences et lettres, 2023. http://www.theses.fr/2023UPSLE005.
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L’alcalinité de l’océan (Alk) est essentielle dans l’absorption de carbone atmosphérique et offre une capacité tampon contre l’acidification. Dans le cadre des prévisions de l’absorption de carbone par les océans et des impacts potentiels sur les écosystèmes, la représentation de l’Alk et du principal facteur de sa distribution dans l’océan profond, le cycle du carbonate de calcium (CaCO3), ont souvent été négligés. Cette thèse aborde le manque de considération accordé à l’Alk et au cycle du CaCO3 dans les modèles du système terrestre (ESM) et explore les implications pour le cycle du carbone dans un océan pré-industriel ainsi que dans des scénarios de changement climatique. À travers une intercomparaison des ESMs, une réduction des biais simulés de l’Alk dans la 6ème phase du Projet d’Intercomparaison de Modèles Couplés (CMIP6) est rapportée. Cette réduction peut s’expliquer partiellement par une calcification pélagique accrue, redistribuant l’Alk en surface et renforçant son gradient vertical dans la colonne d’eau. Une revue des modèles de biogéochimie marine utilisés dans les ESMs actuels révèle une représentation diverse du cycle du CaCO3 et des processus affectant l’Alk. Les schémas de paramétrisation de la production, de l’exportation, de la dissolution et de l’enfouissement du CaCO3 varient considérablement, avec une prise en compte généralement limitée à la seule calcite, et sans calcification benthique. Cette diversité entraîne des projections contrastées de l’export de carbone associé au CaCO3 depuis l’océan de surface vers l’océan profond dans les scénarios futurs. Cependant, des simulations de sensibilité effectuées avec le modèle de biogéochimie marine NEMO-PISCES indiquent que la rétroaction associée sur le flux de carbone anthropique et l’acidification des océans reste limitée. À travers un ensemble de simulations NEMO-PISCES, il est démontré qu’une attention particulière au bilan d’Alk est cruciale pour estimer le dégazage de carbone océanique pré-industriel dû aux apports fluviaux ainsi qu’à l’enfouissement de matière organique et de CaCO3. De telles estimations sont fondamentales pour évaluer le flux de carbone air-mer anthropique en utilisant des données d’observation, et mettent en évidence la nécessité de mieux contraindre le bilan d’Alk de l’océan. Enfin, fidèle au message qu’elle véhicule sur le changement climatique, cette thèse offre une perspective nouvelle et radicale sur les sciences du climat et le système de la recherche actuelOcean alkalinity (Alk) is critical for the uptake of atmospheric carbon and provides buffering capacity against acidification. Within the context of projections of ocean carbon uptake and potential ecosystem impacts, the representation of Alk and the main driver of its distribution in the ocean interior, the calcium carbonate (CaCO3) cycle, have often been overlooked. This thesis addresses the lack of consideration given to Alk and the CaCO3 cycle in Earth system models (ESMs) and explores the implications for the carbon cycle in a pre-industrial ocean as well as under climate change scenarios. Through an ESM intercomparison, a reduction in simulated Alk biases in the 6th phase of the Coupled Model Intercomparison Project (CMIP6) is reported. This reduction can be partially explained by increased pelagic calcification, redistributing Alk at the surface and strengthening its vertical gradient in the water column. A review of the ocean biogeochemical models used in current ESMs reveals a diverse representation of the CaCO3 cycle and processes affecting Alk. Parameterization schemes for CaCO3 production, export, dissolution, and burial vary substantially, with no benthic calcification and generally only calcite considered. This diversity leads to contrasting projections of carbon export associated with CaCO3 from the surface ocean to the ocean interior in future scenarios. However, sensitivity simulations performed with the NEMO-PISCES ocean biogeochemical model indicate that the feedback of this on anthropogenic carbon fluxes and ocean acidification remains limited. Through an ensemble of NEMO-PISCES simulations, careful consideration of the Alk budget is shown to be critical to estimating pre-industrial ocean carbon outgassing due to riverine discharge and the burial of organic matter and CaCO3. Such estimates are fundamental to assessing anthropogenic air-sea carbon fluxes using observational data and highlight the need for greater constraints on the ocean Alk budget
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Lemaitre, Nolwenn. "Approche multi-proxy (Thorium-234, Baryum en excès) des flux d'export et de reminéralisation du carbone et des éléments nutritifs associés à la pompe biologique océanique". Thesis, Brest, 2017. http://www.theses.fr/2017BRES0009/document.
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L’objectif principal de cette thèse est de mieux comprendre les différents facteurs contrôlant la pompe biologique de carbone en Atlantique Nord et dans l’Océan Austral, à proximité des îles Kerguelen, en utilisant notamment deux approches: le Thorium-234 (234Th) et le baryum biogénique (Baxs).En Atlantique Nord, les flux d’export de carbone organique particulaire (POC) augmentent lorsqu’ils sont associés à des minéraux biogéniques (silice biogénique et carbonate de calcium) et lithogènes, capable de lester les particules. L’efficacité d’export, généralement plus faible que précédemment supposé (< 10%), est inversement corrélée à la production, soulignant un décalage temporel entre production et export. La plus forte efficacité de transfert, i.e. la fraction de POC atteignant 400m, est reliée à des particules lestées par du carbonate de calcium ou des minéraux lithogènes.Les flux de reminéralisation mésopélagique sont similaires ou parfois supérieurs aux flux d’exports et dépendent de l’intensité du développement phytoplanctonique, de la structure en taille, des communautés phytoplanctoniques et des processus physiques (advection verticale).Comme observé pour le POC, l’export des éléments traces est influencé par les particules lithogènes provenant des marges océaniques, mais aussi des différentes espèces phytoplanctoniques.Dans l’Océan Austral, la zone à proximité de l’île de Kerguelen est naturellement fertilisée en fer, augmentant les flux d’export de fer, d’azote et de silice biogénique. Il a été démontré que la variabilité des flux dépendait des communautés phytoplanctoniques dans la zone fertiliséeThe main objective of this thesis is to improve our understanding of the different controls that affect the oceanic biological carbon pump. Particulate export and remineralization fluxes were investigated using the thorium-234 (234Th) and biogenic barium (Baxs) proxies.In the North Atlantic, the highest particulate organic carbon (POC) export fluxes were associated to biogenic (biogenic silica or calcium carbonate) and lithogenic minerals, ballasting the particles.Export efficiency was generally low (< 10%) and inversely related to primary production, highlighting a phase lag between production and export. The highest transfer efficiencies, i.e. the fraction of POC that reached 400m, were driven by sinking particles ballasted by calcite or lithogenic minerals.The regional variation of mesopelagic remineralization was attributed to changes in bloom intensity, phytoplankton cell size, community structure and physical forcing (downwelling). Carbon remineralization balanced, or even exceeded, POC export, highlighting the impact of mesopelagic remineralization on the biological pump with a near-zero, deep carbon sequestration for spring 2014.Export of trace metals appeared strongly influenced by lithogenic material advected from the margins. However, at open ocean stations not influenced by lithogenic matter, trace metal export rather depended on phytoplankton activity and biomass.A last part of this work focused on export of biogenic silica, particulate nitrogen and iron near the Kerguelen Island. This area is characterized by a natural iron-fertilization that increases export fluxes. Inside the fertilized area, flux variability is related to phytoplankton community composition
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Noury, Adrien. "Photonique hybride des nanotubes de carbone". Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112199/document.
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L’intégration des communications optiques sur puce offre de vastes promesses en termes de performances et de réduction de la puissance consommée, les canaux optiques ne souffrant pas des nombreuses limitations des canaux métalliques. De plus, l’information codée optiquement permet d’atteindre des débits de données élevés par le biais du multiplexage en longueur d’onde. Afin de conserver la compatibilité avec les composants électroniques, les communications et composants optiques doivent s’intégrer dans la filière silicium. Cependant, ce dernier matériau ne permet pas d’envisager la réalisation de certaines fonctions optiques, en particulier la source laser. D’autres matériaux doivent ainsi être intégrés pour suppléer au silicium. Mes travaux de thèse portent sur l’intégration de nanotubes de carbone sur plate-forme silicium pour la photonique. Dans ces travaux, le potentiel des nanotubes de carbone pour la réalisation de sources optiques intégrées est exploré. Dans un premier temps, je proposerai des pistes de compréhension de l’apparition du gain optique dans les nanotubes de carbone semiconducteurs par analyse des temps de vie des excitons, mesurés en spectroscopie pompe-sonde. Ces temps de vie sont sensiblement rallongés lorsque la centrifugation des nanotubes de carbone, au cours de l’extraction, est poussée à des vélocités et des temps plus longs. Une explication envisagée est la réduction du nombre de défauts à la surface des nanotubes, ces défauts se comportant comme des centres de recombinaison non-radiatifs. D’autre part, une méthode efficace d’intégration des nanotubes de carbone sur guide d’onde silicium a été proposée. Cette méthode robuste et permet d’observer le couplage de la photoluminescence des nanotubes de carbone avec le mode optique du guide d’onde. Afin d’obtenir une interaction exaltée entre mode optique et nanotube de carbone, le couplage entre les nanotubes et différentes cavités photoniques, incluant microdisques, cavités Fabry-Pérot et micro-résonateurs en anneau, a été étudié. L’emploi en particulier de résonateurs en anneau permet d’observer la structuration de la photoluminescence des nanotubes de carbone par les modes de résonance de l’anneau. Différentes configurations ont été étudiées afin de compléter la compréhension des mécanismes de couplage : micro-photoluminescence, photoluminescence guidée et photoluminescence intégréeOn-chip optical communication may increase drastically performances and consumption of communication systems. Indeed, optical channels do not face limitations that metallics interconnects do. Even better would be the achievable data rate due to the multiplexing possibility in optics. In order to keep compatibility with electronic devices, optical components and interconnects should be built in silicon. However, this material is not suitable for some optical function, such as laser sources. Thus, there is a need to integrate alternative materials to compensate for silicon weaknesses. My PhD work focuses on integration of carbon nanotube on silicon for photonics applications. In this work, potential use of carbon nanotube for light emission function is investigated. First, I will propose clue to understand the appearance of optical gain in semiconducting carbon nanotube. Such investigation is done by mean of pump-probe experiments, where the excitons lifetimes are measured. Those lifetimes slightly increase while centrifugation time and speed is increased, during the extraction process. A possible explanation is that defect-free carbon nanotubes are selected by the centrifugation process. In parallel, I worked on designing an efficient method to couple nanotubes photoluminescence with silicon waveguides. This method appears to be quite robust, and allows to observe coupling between the nanotube photoluminescence and the optical mode of the waveguide. In order to obtain a more intense interaction between the optical mode and carbon nanotubes, I investigated the coupling between carbon nanotubes and several photonic cavities, including microdisks, Fabry-Pérot cavities and ring resonators. Specifically, ring resonators allow to measure the photoluminescence of carbon nanotube structured by the resonant modes. Several configurations are studied to understand more in-depth the coupling mechanisms: micro-photoluminescence, guided photoluminescence and integrated photoluminescence
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Stenman, David. "Advanced oxidation technologies for the pulp industry : an investigation on the delignifying properties of the carbonate radical anion /". Stockholm : Department of Chemistry - Nuclear Chemistry, Kungliga tekniska högskolan, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-69.
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Bouchachi, Nawal. "Assessing the role of the microbial carbon pump in carbon cycling in the Mediterranean Sea". Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS165.
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La matière organique dissoute (MOD) est l'un des plus grands réservoirs de carbone réduit sur terre, contenant à peu près la même quantité de carbone que le CO2 dans l'atmosphère. Les procaryotes hétérotrophes (PH, bactéries et archées) jouent un rôle clé dans le cycle de la MOD dans l'océan. Ils transforment environ la moitié du carbone fixé par les producteurs primaires pour produire de la biomasse et du CO2. Cependant, le rôle des PH en tant que source de MOD a reçu moins d'attention. Selon la pompe microbienne de carbone (PMC), les PH produisent de la MOD récalcitrante, c'est-à-dire des composés qui résistent à une reminéralisation et sont donc stockés dans l'océan pour des milliers d'années. Dans les systèmes oligotrophes, tels que la mer Méditerranée, la PMC devrait jouer un rôle majeur dans le piégeage du carbone. Les raisons ultimes de la production de cette MOD et les conditions qui la rendent réfractaire ne sont pas encore claires. Nous visant à comprendre les facteurs régissant la PMC, avec un accent particulier sur la dynamique de la MOD en Méd., un écosystème oligotrophe particulièrement limité en phosphore et très vulnérable au changement climatique. Nous répondons surtout à 3 questions : quel est l’effet de la limitation en P sur la quantité et la qualité de la MOD dérivée des PH (MOD-PH? La limitation en P affecte-t-elle la biodisponibilité de MOD-PH? Quelles sont les variations saisonnières de la composition et la biodisponibilité de la MOD en Méd. et quel est le rôle des PH dans cette variabilité ? Pour la 1ère question, des incubations ont été menées en utilisant des souches bactériennes seules et des communautés PH mixtes. Elles ont été réalisées dans de l'eau de mer artificielle avec une seule source de carbone (glucose) sous des concentrations de P contrastées, et la MOD-PH a été quantifiée et caractérisée à la phase de croissance stationnaire. Nous avons montré que la limitation en P n'affectait pas la quantité de la MOD-HP mais plutôt sa qualité, mesurée par spectroscopie de fluorescence (MODF), avec une prédominance de MODF de type humique sous limitation en P de et MODF de type protéique en absence de limitation. Cette MOD a ensuite été utilisée comme substrat pour des procaryotes naturels afin de tester sa biodisponibilité. On a observé que MOD-PH a favorisé une croissance significative dans tous les traitements, et aucune différence claire dans la labilité de la MOD-PH n'a été démontré à partir de la croissance des procaryotes. Mais les différentes qualités de MOD-PH ont sélectionné pour différents taxons indicateurs. Nos résultats soulignent que la labilité de la MOD dépend à la fois de sa qualité, déterminée par la disponibilité du P, et de la composition de la communauté. Pour voir si résultats observés en laboratoire pouvaient être traduits en observations sur le terrain, un échantillonnage a été conduit en Méd. de 2019 à 2021 pour suivre les changements temporels de la composition de la MOD, mesurée par spectrométrie de masse à résonance cyclotronique ionique à transformée de Fourier (FT-ICR MS) avec d'autres descripteurs de la MOD, des mesures microbiennes et environnementales. On a postulé que la qualité de la MOD de surface en Méd. passe de labiles à réfractaires pendant la période d'accumulation en été, et que les PH jouent un rôle majeur dans sa formation. Les indices de récalcitrance de la MOD ont augmenté en été, confirmant notre hypothèse. L’augmentation de diversité fonctionnelle chimique de la MOD suggère que la MOD résulte de l'interaction entre différents processus: la production primaire dissoute, l’activité des PH et la photodégradation qui diversifient la MOD la rendant récalcitrants. Dans l'ensemble, cette thèse rassemble des observations expérimentales et in situ de paramètres biogéochimiques et microbiens pour comprendre le rôle de la pompe à carbone microbienne dans le cycle de la MOD dans l'océanDissolved organic matter (DOM) is one of the largest reservoirs of reduced carbon on earth, containing roughly the same amount of carbon as CO2 in the atmosphere. Heterotrophic prokaryotes (HP, Bacteria and Archaea) play a key role in DOM cycling in the ocean. They process about half of the carbon fixed by primary producers, either to produce biomass or CO2. However, less attention has been paid to the role of HP as DOM source. The so-called microbial carbon pump (MCP) states that HP produce recalcitrant DOM, this is, compounds that resist further remineralization and are thus stored in the ocean for thousands of years. In oligotrophic ecosystems, such as the Mediterranean Sea, the MCP is predicted to play a major role in carbon sequestration. The ultimate reasons why this DOM is produced, and which are the conditions that make it refractory, remain unclear. Our objective is to understand the environmental factors driving the MCP, with a particular focus on DOM dynamics in Med Sea, an oligotrophic ecosystem particularly limited in phosphorus and highly vulnerable to climate change. We mainly answer 3 questions: Is the quantity and quality of HP-derived DOM (HP-DOM) dependent on P limitation? Does P limitation affect the bioavailability of HP-DOM?. How does DOM composition and bioavailability change seasonally in the Med Sea and what is the role of HP on this variability?To determine the effect of P limitation on HP-DOM, lab incubations were carried out using single bacterial strains and mixed HP communities. Incubations were done in artificial sea water with a single carbon source (glucose) under contrasting P concentrations, and HP-DOM was quantified and characterized at the stationary growth phase. Here, we showed that P limitation did not significantly affect the quantity of HP-DOM but it affected its quality, measured by fluorescence spectroscopy (FDOM), with a predominance of humic-like FDOM under P limitation but protein-like FDOM under P repletion. This HP-DOM was then used as a substrate for natural prokaryotes to test the bioavailability of the HP-DOM released under P repletion or P limitation (chapter II). These experiments demonstrated that HP-DOM promoted significant growth in all treatments, and no clear differences in HP-DOM lability were evidenced based on the prokaryotic growth. But HP-DOM supported the growth of diverse communities and P-driven differences in HP-DOM quality selected for different indicator taxa. Our findings emphasize that HP-DOM lability is dependent on both DOM quality, shaped by P availability, and the composition of the consumers community. To see if HP-DOM release patterns observed in the lab could be translated into field observations, sampling in the Med Sea was carried from 2019 to 2021 to follow temporal changes in DOM composition, measured by Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) together with other DOM descriptors (DOC, FDOM, etc.), microbial and environmental measures. We hypothesized that DOM composition in the surface Med Sea changes from labile to refractory compounds during the summer accumulation period, and that HP might play a significant role in its formation. DOM recalcitrance proxies (aromaticity, unsaturation and molecular size) increased in summer; confirming our hypothesis of an increase in DOM recalcitrance in the mixed layer during stratification. DOM molecular and chemical functional diversity also increased, suggesting that the accumulated DOM in summer is likely the result of the interplay between different processes: dissolved primary production, prokaryotic processing and photobleaching that transform DOM into a highly diverse pool enriched in recalcitrant compounds. Overall, this thesis brings together experimental and in situ observations of biogeochemical and microbial parameters to understand the role of the microbial carbon pump in DOM cycling in the ocean
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Dellero, Tarik. "Étude d'un système à absorption solide pour le chauffage et la réfrigération utilisant des fibres de carbone comme additif". Grenoble INPG, 1997. http://www.theses.fr/1997INPG0127.
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Le systeme a absorption pour le stockage de l'energie thermique que nous avons etudie utilise une reaction faisant intervenir le chlorure manganeux (mncl#2) et l'ammoniac (nh#3). Cette reaction est reversible et permet de stocker la chaleur dans un sens et de la restituer dans l'autre sens tandis que la condensation et la l'evaporation de l'ammoniac servant a stocker et restituer le froid. En premier lieu, nous avons montre que l'utilisation des fibres de carbone comme additif permet d'ameliorer la cinetique et le rendement energetique de la reaction etudiee. Nous avons en meme temps trouve deux methodes originales et efficaces pour lier intimement les fibres de carbone aux composes de reaction : l'insertion et l'impregnation de mncl#2 dans les fibres de carbone. Des methodes physico-chimiques nous ont permis d'obtenir les informations suivantes sur les reactifs : la chaleur specifique (par microcalorimetrie), la conductivite thermique (par la methode flash), le coefficient d'echange de chaleur, la porosite (par adsorption des gaz et porosimetrie au mercure) et la permeabilite aux gaz. En dernier lieu, nous avons mene une etude de modelisation des transferts thermiques et de la cinetique de reaction.
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Langlois, Benjamin. "Propriétés optiques hors-équilibre des nanotubes de carbone nus ou fonctionnalisés". Thesis, Paris, Ecole normale supérieure, 2014. http://www.theses.fr/2014ENSU0017/document.
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Cette thèse est consacrée à l'étude expérimentale par spectroscopie pompe-sonde femtoseconde des propriétés optiques hors-équilibre de solutions micellaires de nanotubes de carbone. Les propriétés des nanotubes de carbone sont profondément affectées par leur géométrie unidimensionnelle. Les interactions coulombiennes exaltées du fait du confinement quantique des électrons à une dimension donnent naissance à des excitons fortement liés. L'analyse des spectres d'absorption transitoire par la méthode des moments permet une étude des interactions entre excitons. La relaxation des excitons s'avère gouvernée par les collisions entre excitons, limitées par la diffusion à 1D dans le nanotube. La présence d'excitons dans une sousbande conduit à un décalage uniforme vers le bleu de l'ensemble des transitions excitoniques et à un élargissement de même ampleur. Ainsi, les interactions croisées entre excitons de sousbandes différentes sont de même amplitude qu'entre excitons de même sousbande, en accord avec une modélisation simple.Par ailleurs, les nanotubes sont constitués uniquement d'atomes de surface, ce qui leur confère une forte sensibilité à l'environnement. Cette sensibilité est mise à profit dans des composés hybrides où la fonctionnalisation non-covalente par des colorants ouvre une nouvelle voie d'excitation des nanotubes. Notre étude montre que le transfert d'énergie entre les colorants et les nanotubes permet une excitation monochromatique efficace et uniforme de l'ensemble des espèces de nanotubes. Une fois l'exciton transféré au nanotube, sa relaxation s'avère ensuite identique à celle observée dans les nanotubes nusThis thesis is devoted to the experimental study by femtosecond pump-probe spectroscopy of micellar solutions of carbon nanotubes. The properties of carbon nanotubes are greatly affected by their 1D geometry. Quantum confinement of electrons in 1D leads to enhanced coulomb interactions giving rise to strongly bound excitons. Many-body effects between excitons is investigated by the moment method analysis of the transient absorption spectra. The relaxation of excitons is controlled by diffusion-limited collisions between excitons. The presence of excitons in the lowest subband results in a broadening and an uniform blue-shift of the excitonic energy spectrum. Intra and intersubband interactions turn out to be of the same magnitude, in agreement with a simple mean field theory of excitonic interactions.Moreover, the one-layer structure of nanotubes results in strong interaction with the environment. We take advantage of the environmental sensitivity of nanotubes in hybrid compounds where the non-covalent functionalization with dyes opens a new extrinsic monochromatic excitation channel of the nanotubes through an efficient and ultrafast energy transfer between dyes and nanotubes. Once the exciton transferred to the nanotube, its relaxation is similar to the one observed in bare nanotubes
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Terrats, Louis. "Le flux de carbone particulaire et le lien avec la communauté phytoplanctonique : une approche par flotteurs-profileurs biogéochimiques". Electronic Thesis or Diss., Sorbonne université, 2022. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2022SORUS550.pdf.
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L'Océan est un acteur majeur du climat en échangeant avec l'atmosphère de grandes quantités de carbone. Le carbone atmosphérique est fixé à la surface de l’océan par le phytoplancton qui le transforme en carbone biogène, dont une partie est transportée vers l’océan profond par des mécanismes physiques et biologiques; il s’agit de la Pompe Biologique de Carbone (BCP). Une infime partie de ce carbone biogène atteindra des profondeurs suffisantes pour être séquestré durant plusieurs siècles avant qu'il ne retourne dans l'atmosphère, régulant les concentrations atmosphériques de CO2. Aujourd'hui, nous en savons assez sur la BCP pour reconnaitre son importance dans le climat, mais nos connaissances sur son fonctionnement sont limitées en raison d’un échantillonnage insuffisant des flux de carbone biogène. Dans ce travail de thèse, nous avons utilisé les flotteurs BioGéoChimique-Argo, plateformes d’observations conçues pour résoudre le problème du sous-échantillonnage, afin d’explorer un mécanisme majeur de la BCP qui est la pompe gravitationnelle. La pompe gravitationnelle est le transport du carbone biogène sous la forme de particules organiques (POC) qui sédimentent de la surface vers l’océan profond. Notre étude de la pompe gravitationnelle se divise en trois axes. Le premier axe consiste au développement d’une méthode pour détecter les floraisons de coccolithophoridés, groupe phytoplanctonique majeur qui a potentiellement un contrôle important sur le transport du POC en profondeur. Le deuxième axe est centré sur la variabilité saisonnière et régionale des flux de POC dans l’Océan Austral, qui est une zone sous-échantillonnée mais dans laquelle plusieurs flotteurs ont été déployés avec une trappe optique à sédiments (OST). Seuls une dizaine de flotteurs sont équipés d’OST, ce qui est faible en comparaison avec l’ensemble de la flotte BGC-Argo (i.e. plusieurs centaines de flotteurs). C’est pourquoi nous avons développé, dans le troisième axe, une méthode pour estimer le flux de POC avec les capteurs standards du programme BGC-Argo. Cette méthode a ensuite été appliquée à une centaine de flotteurs pour décrire la variabilité saisonnière du flux de POC dans de nombreuses régions océaniques. Dans ce travail de thèse, nous mettons également en évidence le lien entre la variabilité des flux et la nature des particules en surface. Par exemple, nous avons calculé des relations entre la composition de la communauté phytoplanctonique et les flux de POC à 1000m. En utilisant ces relations, nous avons ensuite utilisé les observations satellites pour extrapoler les flux de POC à de larges échelles spatiales, comme à l’ensemble de l’Océan Austral et de l’océan globalThe ocean plays a key role in the climate by exchanging large quantities of carbon with the atmosphere. Atmospheric carbon is fixed at the ocean surface by phytoplankton that transforms it into biogenic carbon, part of which is transported to the deep ocean by physical and biological mechanisms; this is the Biological Carbon Pump (BCP). A tiny fraction of this biogenic carbon reaches sufficient depths to be sequestered for several centuries before it returns to the atmosphere, thus regulating concentrations of atmospheric CO2. Today, we know enough about the BCP to recognize its importance in climate, but our knowledge of its functioning is limited due to insufficient sampling of biogenic carbon fluxes. Here, we used BioGeoChimical-Argo floats, observational platforms designed to solve the undersampling problem, to explore a major mechanism of the BCP called the gravitational pump. The gravitational pump is the transport of biogenic carbon in the form of organic particles (POC) that sink from the surface into the deep ocean. Our study of the gravitational pump is divided into three axes. The first axis consisted of developing a method to detect blooms of coccolithophores, a major phytoplankton group that potentially has an important control on the transport of POC at depth. The second axis focused on the seasonal and regional variability of POC fluxes in the Southern Ocean, an undersampled area in which several floats have been deployed with an optical sediment trap (OST). Only ten floats were equipped with an OST, which is low compared to the whole BGC-Argo fleet (i.e. several hundred floats). Therefore, in the third axis, we developed a method to estimate the POC flux with the standard sensors of BGC-Argo floats. This method was then applied to hundreds of floats to describe the seasonal variability of the POC flux in many regions. In this study, we also highlighted the link between the POC flux and the nature of surface particles. For example, we calculated relationships between phytoplankton community composition and POC flux at 1000m. Using these relationships, we then used satellite observations to extrapolate POC flux to large spatial scales, such as the entire Southern Ocean and the global ocean
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Caffin, Mathieu. "Devenir de la fixation d'azote et export de carbone dans l'océan Pacifique tropical sud-ouest". Thesis, Aix-Marseille, 2018. http://www.theses.fr/2018AIXM0475/document.
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Ce travail de thèse porte sur la quantification de la diazotrophie et son influence sur les cycles biogéochimiques dans l'océan de surface Pacifique tropical sud-ouest, une région particulièrement sous-échantillonnée à ce jour. Les objectifs de ce travail étaient (1) de quantifier la fixation de N2 et identifier les principaux acteurs de la diazotrophie dans cette région, (2) d’évaluer l'influence de la fixation de N2 sur la production primaire et sur l'export de carbone, (3) d’identifier les voies de transfert de l’azote fixé dans la chaine trophique planctonique.Il a été mis en évidence que la région du Pacifique tropical sud-ouest était un hot spot de fixation de N2. A l'ouest, les eaux oligotrophes des archipels Mélanésiens présentaient des taux de fixation de N2 élevés et la communauté diazotrophe était dominée par Trichodesmium. A l'est, les eaux ultra-oligotrophes de la gyre du Pacifique sud présentaient des taux de fixation de N2 plus faibles et la communauté diazotrophe était dominée par les UCYN-B.Des bilans d'azote montrent que la fixation de N2 contribuait à plus de 90 % des apports d'azote nouveau dans la couche euphotique, et soutenait donc la quasi intégralité de la production primaire nouvelle. L'étude des voies de transfert de l'azote fixé montre qu’entre 7 et 15 % de la fixation de N2 totale était transféré vers les organismes non-diazotrophes.Ces travaux de thèse démontrent que la diazotrophie soutient la pompe biologique dans l'océan Pacifique tropical sud-ouest, et qu'elle peut jouer un rôle déterminant dans la structure des communautés planctoniques et les cycles biogéochimiques du carbone et de l'azote dans les régions oligotrophesThis PhD thesis focuses on the quantification of diazotrophy and its influence on biogeochemical cycles in the western tropical South Pacific Ocean, a critically under-sampled region so far. The aim of this work is to (1) quantify N2 fixation and identify the main contributors of diazotrophy in this region, (2) assess the influence of N2 fixation on primary production and carbon export, (3) identify transfer pathways of the fixed nitrogen in the planktonic food web.We have found that the western tropical South Pacific Ocean was a hotspot of N2 fixation. In the western part, the oligotrophic waters of the Melanesian archipelago presented high N2 fixation rates and diazotrophes were dominated by Trichodesmium. In the eastern part, the ultra-oligotrophic waters of the South Pacific gyre presented lower N2 fixation rates, and diazotrophs were dominated by UCYN-B.The nitrogen budgets show that N2 fixation contributed to more than 90 % of the of new nitrogen input in the photic layer. The study of the transfer pathways of the fixed nitrogen has shown that 7 to 15 % of total N2 fixation was transferred to non-diazotrophs.This PhD thesis indicates that diazotrophy sustains the biological pump in the western tropical South Pacific Ocean, and can have a critical influence in the planktonic community structure and in biogeochemical cycles of carbon and nitrogen in oligotrophic regions
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Drago, Laetitia. "Analyse globale de la pompe à carbone biologique à partir de données en imagerie quantitative". Electronic Thesis or Diss., Sorbonne université, 2023. http://www.theses.fr/2023SORUS562.
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La pompe à carbone biologique (PCB) joue un rôle central dans le cycle global du carbone océanique, en transportant le carbone de la surface vers les profondeurs et en le séquestrant pendant de longues périodes. Ce travail vise à analyser deux acteurs clés de la PCB : le zooplancton et les particules. Pour cela, nous utilisons les données d'imagerie in situ de l'Underwater Vision Profiler (UVP5) pour étudier deux axes principaux : 1) la distribution globale de la biomasse du zooplancton et 2) l'exportation de carbone dans le contexte d'une efflorescence printanière dans l'Atlantique Nord. À l'aide de l'UVP5 et de l'apprentissage automatique par le biais de modèles d'habitat utilisant des arbres de régression boostés, nous étudions la distribution mondiale de la biomasse du zooplancton et ses implications écologiques. Les résultats montrent des valeurs maximales de biomasse autour de 60°N et 55°S et des valeurs minimales au niveau des gyres océaniques, avec une biomasse globale dominée par les crustacés et les rhizaires. En utilisant des techniques d'apprentissage automatique sur des données globalement homogènes, cette étude fournit des informations sur la distribution de 19 grands groupes de zooplancton (1-50 mm de diamètre sphérique équivalent). Ce premier protocole permet d'estimer la biomasse du zooplancton et la composition de la communauté à l'échelle globale à partir d'observations d'imagerie in situ d'organismes individuels. Dans le contexte unique de la campagne EXPORTS 2021, nous analysons les données UVP5 obtenues par le déploiement de trois instruments dans un tourbillon à forte rétention. Après avoir regroupé les 1 720 914 images à l'aide de Morphocluster, un logiciel de classification semi-autonome, nous nous intéressons aux caractéristiques des particules marines, en étudiant leur morphologie à travers un cadre oblique qui suit un panache de particules entre la surface et 800 m. Les résultats montrent que, contrairement aux attentes, les agrégats deviennent de manière inattendue plus grands, plus denses, plus circulaires et plus complexes avec la profondeur. En revanche, l'évolution des pelottes fécales est plus hétérogène et façonnée par l'activité du zooplancton. Ces résultats remettent en question les attentes antérieures et appellent à une réévaluation de notre vision des agrégats et des pelottes fécales. Nous avons également étudié la dynamique des concentrations et des flux de carbone à l'aide d'un cadre 1D plus traditionnel dans lequel nous explorons les trois éléments clés de l'estimation des flux à partir d'imagerie in situ en comparant les estimations de l'UVP5 et des pièges à sédiments: la gamme de tailles couvertes, la vitesse de sédimentation et le contenu en carbone. Selon la littérature, les pièges à sédiments à flottabilité neutre (NBST) et les pièges attachés à la surface (STT) couvrent généralement une gamme de tailles allant de 10 µm à environ 2 mm. Dans notre étude, nous avons constaté qu'en élargissant la gamme de tailles de l'UVP5 à 10 µm et en la limitant à 2 mm, une comparaison plus consistante peut être faite entre le flux issu de l'UVP5 et celui des pièges à sédiments (obtenus par des collègues). Toutefois, il reste une contribution importante du flux au-dessus de ce seuil de taille qui nécessite une étude plus approfondie de ses implications par l'utilisation d'approches complémentaires telles que des pièges à sédiments avec des ouvertures plus grandes. Ce manuscrit ne fait pas seulement progresser nos connaissances, mais il aborde également des défis critiques dans l'estimation de la biomasse du zooplancton et de la dynamique des particules pendant les événements d'export. Les résultats de cette étude ouvrent de nouvelles voies pour la recherche future sur la PCB et approfondissent notre compréhension des écosystèmes marinsThe biological carbon pump (BCP) plays a central role in the global ocean carbon cycle, transporting carbon from the surface to the deep ocean and sequestering it for long periods. This work aims to analyse two key players of the BCP: zooplankton and particles. To this end, we use in situ imaging data from the Underwater Vision Profiler (UVP5) to investigate two primary axes: 1) the global distribution of zooplankton biomass and 2) carbon export in the context of a North Atlantic spring bloom. Our objectives includes a quantification of global zooplankton biomass, enhancing our comprehension of the BCP via morphological analysis of particles, and assessing and comparing the gravitational flux of detrital particles during a the North Atlantic spring bloom using high-resolution UVP5 data. With the help of UVP5 imagery and machine learning through habitat models using boosted regression trees, we investigate the global distribution of zooplankton biomass and its ecological implications. The results show maximum zooplankton biomass values around 60°N and 55°S and minimum values within the oceanic gyres, with a global biomass dominated by crustaceans and rhizarians. By employing machine learning techniques on globally homogeneous data, this study provides taxonomical insights into the distribution of 19 large zooplankton groups (1-50 mm equivalent spherical diameter). This first protocol estimates global, spatially resolved zooplankton biomass and community composition from in situ imaging observations of individual organisms. In addition, within the unique context of the EXPORTS 2021 campaign, we analyse UVP5 data obtained by deploying three instruments in a highly retentive eddy. After clustering the 1,720,914 images using Morphocluster, a semi-autonomous classification software, we delve into the characteristics of the marine particles, studying their morphology through an oblique framework that follows a plume of detrital particles between the surface and 800 m depth. The results of the plume following approach show that, contrary to expectations, aggregates become unexpectedly larger, denser, more circular and more complex with depth. In contrast, the evolution of fecal pellets is more heterogeneous and shaped by zooplankton activity. Such results challenge previous expectations and may require a reassessment of our view of sinking aggregates and fecal pellets. We also studied concentration and carbon flux dynamics using a more traditional 1D framework where we explore the three key elements in flux estimation from in situ imaging data by comparing UVP5 and sediment trap flux estimates: size range covered, sinking rate and carbon content. According to the current literature, neutrally buoyant sediment traps (NBST) and surface-tethered traps (STT) usually cover a size range from 10 µm to approximately 2 mm. In our study, we have found that by expanding the UVP size range to 10 µm and limiting it to 2 mm, a more consistent comparison can be made between UVP5-generated flux and sediment trap fluxes (obtained by colleagues). However, it is worth noting that there remains a large flux contribution above this size threshold, necessitating further investigation of its implications through the use of complementary approaches such as the use of sediment traps with larger openings. This manuscript not only advances our knowledge, but also addresses critical challenges in estimating zooplankton biomass and particle dynamics during export events. The findings of this study open up new avenues for future research on the biological carbon pump and deepen our understanding of marine ecosystems
Libros sobre el tema "Carbonate pump"
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O'Neil, Darcy. Fix the pumps. [S.l.]: Art of Drink, 2009.
Buscar texto completoCapítulos de libros sobre el tema "Carbonate pump"
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Kirchman, David L. "Slow Carbon and Deep Time". En Microbes, 87–107. Oxford University PressNew York, 2024. http://dx.doi.org/10.1093/oso/9780197688564.003.0006.
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Abstract The fast carbon cycle is populated by microbes with lifespans measured in hours, whereas the slow carbon cycle operates over thousands to millions of years. One connection between the two cycles is the calcium carbonate synthesized by the alga coccolithophore, as part of the carbonate pump which sequesters carbon in deep sediments for millions of years. Symbiotic algae help another major producer of calcium carbonate, reef-building corals. Before coccolithophores and corals had evolved, calcium carbonate built up in massive stromatolites during the Precambrian. Fossil stromatolites yield evidence of how and when life first evolved on Earth. Once a rock is exposed to air or water, it is rapidly colonized by microbes, setting in motion forces that end in the rock’s eventual demise. The breakup of carbonate and silicate rocks, or weathering, augmented by microbes, consumes carbon dioxide and regulates global temperatures and Earth’s climate over hundreds to thousands of years.
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Dolman, Han. "The Carbon Cycle". En Biogeochemical Cycles and Climate, 129–58. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198779308.003.0009.
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The chapter first shows carbon dioxide variability over long geological timescales. The current stocks and fluxes of carbon are then given, for the whole planet and for the atmosphere, ocean and land separately. The main flows of carbon in the ocean, through the biological pump (via uptake through photosynthesis) and the physical pump (via involving chemical transformation uptake in water and production of carbonate), and on land, through photosynthesis (Gross Primary Production) and respiration leading to Net Primary Production, Net Ecosystem Production and Net Biome Production and through the storage of carbon in biomass, are described. Next, carbon interactions during the Paleocene–Eocene Thermal Maximum and glacial–interglacial transitions, thought to involve changes in ocean circulation and upwelling, are examined. The key changes from anthropogenic perturbation of the natural carbon cycle are shown to be due to fossil fuel burning and land-use change (deforestation). The effects of the carbon–climate feedback on temperature and carbon stocks are also shown.
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Gehlen, Marion y Nicolas Gruber. "Biogeochemical Consequences of Ocean Acidification and Feedbacks to the Earth System". En Ocean Acidification. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199591091.003.0017.
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By the year 2008, the ocean had taken up approximately 140 Gt carbon corresponding to about a third of the total anthropogenic CO2 emitted to the atmosphere since the onset of industrialization (Khatiwala et al. 2009 ). As the weak acid CO2 invades the ocean, it triggers changes in ocean carbonate chemistry and ocean pH (see Chapter 1). The pH of modern ocean surface waters is already 0.1 units lower than in pre-industrial times and a decrease by 0.4 units is projected by the year 2100 in response to a business-as- usual emission pathway (Caldeira and Wickett 2003). These changes in ocean carbonate chemistry are likely to affect major ocean biogeochemical cycles, either through direct pH effects or indirect impacts on the structure and functioning of marine ecosystems. This chapter addresses the potential biogeochemical consequences of ocean acidification and associated feedbacks to the earth system, with focus on the alteration of element fluxes at the scale of the global ocean. The view taken here is on how the different effects interact and ultimately alter the atmospheric concentration of radiatively active substances, i.e. primarily greenhouse gases such as CO2 and nitrous oxide (N2O). Changes in carbonate chemistry have the potential for interacting with ocean biogeochemical cycles and creating feedbacks to climate in a myriad of ways (Box 12.1). In order to provide some structure to the discussion, direct and indirect feedbacks of ocean acidification on the earth system are distinguished. Direct feedbacks are those which directly affect radiative forcing in the atmosphere by altering the air–sea flux of radiatively active substances. Indirect feedbacks are those that first alter a biogeochemical process in the ocean, and through this change then affect the air–sea flux and ultimately the radiative forcing in the atmosphere. For example, when ocean acidification alters the production and export of organic matter by the biological pump, then this is an indirect feedback. This is because a change in the biological pump alters radiative forcing in the atmosphere indirectly by first changing the nearsurface concentrations of dissolved inorganic carbon and total alkalinity.
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Riebesell, Ulf y Philippe D. Tortell. "Effects of Ocean Acidification on Pelagic Organisms and Ecosystems". En Ocean Acidification. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780199591091.003.0011.
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Over the past decade there has been rapidly growing interest in the potential effects of ocean acidification and perturbations of the carbonate system on marine organisms. While early studies focused on a handful of phytoplankton and calcifying invertebrates, an increasing number of investigators have begun to examine the sensitivity to ocean acidification of various planktonic and benthic organisms across the marine food web. Several excellent review articles have recently summarized the rapidly expanding literature on this topic (Fabry et al. 2008; Doney et al. 2009 ; Joint et al. 2011). The focus of this chapter is on the potential ecosystem-level effects of ocean acidification. Starting with a brief review of the basic physical, chemical, and biological processes which structure pelagic marine ecosystems, the chapter explores how organismal responses to perturbations of the carbonate system could scale up in both time and space to affect ecosystem functions and biogeochemical processes. As with many chapters in this volume, and indeed much of the ocean acidification literature at present, our review raises more questions than it answers. It is hoped that these questions will prove useful for articulating and addressing key areas of future research. Complexity in marine pelagic food webs results from the interactions of multiple trophic levels across a range of temporal and spatial scales. The traditional view of marine food webs (Steele 1974) involved a relatively short trophic system in which large phytoplankton (e.g. net plankton such as diatoms) were grazed by a variety of mesozooplankton (e.g. copepods), which were in turn consumed by second-level predators, including many economically important fish and invertebrate species. This ‘classic’ marine food web is typical of high-productivity regions such as coastal upwelling regimes (Lassiter et al. 2006). A characteristic feature of these systems is a strong decoupling between primary production and grazing, which results from the different metabolic rates of consumers and producers and, in many cases, ontogenetic and seasonal delays in the emergence of feeding predators. The uncoupling between phytoplankton and their consumers leads to significant export of organic material out of the euphotic zone, the so-called biological carbon pump (discussed further below).
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Bethke, Craig M. "Petroleum Reservoirs". En Geochemical Reaction Modeling. Oxford University Press, 1996. http://dx.doi.org/10.1093/oso/9780195094756.003.0026.
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In efforts to increase and extend production from oil and gas fields, as well as to keep wells operational, petroleum engineers pump a wide variety of fluids into the subsurface. Fluids are injected into petroleum reservoirs for a number of purposes, including: • Waterflooding, where an available fresh or saline water is injected into the reservoir to displace oil toward producing wells. • Improved Oil Recovery (IOR), where a range of more exotic fluids such as steam (hot water), caustic solutions, carbon dioxide, foams, polymers, surfactants, and so on are injected to improve recovery beyond what might be obtained by waterflooding alone. • Near-well treatments, in which chemicals are injected into producing and sometimes injector wells, where they are intended to react with the reservoir rock. Well stimulation techniques such as acidization, for example, are intended to increase the formation's permeability. Alternatively, producing wells may receive “squeeze treatments” in which a mineral scale inhibitor is injected into the formation. In this case, the treatment is designed so that the inhibitor sorbs onto mineral surfaces, where it can gradually desorb into the formation water during production. • Pressure management, where fluid is injected into oil fields in order to maintain adequate fluid pressure in reservoir rocks. Calcium carbonate may precipitate as mineral scale, for example, if pressure is allowed to deteriorate, especially in fields where formation fluids are rich in Ca++ and HCO3- and CO2 fugacity is high. In each of these procedures, the injected fluid can be expected to be far from equilibrium with sediments and formation waters. As such, it is likely to react extensively once it enters the formation, causing some minerals to dissolve and others to precipitate. Hutcheon (1984) appropriately refers to this process as “artificial diagenesis,” drawing an analogy to the role of groundwater flow in the diagenesis of natural sediments (see Chapter 19). Further reaction is likely if the injected fluid breaks through to producing wells and mixes there with formation waters. There is considerable potential, therefore, for mineral scale, such as barium sulfate (see the next section), to form during these procedures.
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Holbourn, Ann, Wolfgang Kuhnt, Karlos G. D. Kochhann, Kenji M. Matsuzaki y Nils Andersen. "Middle Miocene climate–carbon cycle dynamics: Keys for understanding future trends on a warmer Earth?" En Understanding the Monterey Formation and Similar Biosiliceous Units across Space and Time. Geological Society of America, 2022. http://dx.doi.org/10.1130/2022.2556(05).
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ABSTRACT The late early to middle Miocene period (18–12.7 Ma) was marked by profound environmental change, as Earth entered into the warmest climate phase of the Neogene (Miocene climate optimum) and then transitioned to a much colder mode with development of permanent ice sheets on Antarctica. Integration of high-resolution benthic foraminiferal isotope records in well-preserved sedimentary successions from the Pacific, Southern, and Indian Oceans provides a long-term perspective with which to assess relationships among climate change, ocean circulation, and carbon cycle dynamics during these successive climate reversals. Fundamentally different modes of ocean circulation and carbon cycling prevailed on an almost ice-free Earth during the Miocene climate optimum (ca. 16.9–14.7 Ma). Comparison of δ13C profiles revealed a marked decrease in ocean stratification and in the strength of the meridional overturning circulation during the Miocene climate optimum. We speculate that labile polar ice sheets, weaker Southern Hemisphere westerlies, higher sea level, and more acidic, oxygen-depleted oceans promoted shelf-basin partitioning of carbonate deposition and a weaker meridional overturning circulation, reducing the sequestration efficiency of the biological pump. X-ray fluorescence scanning data additionally revealed that 100 k.y. eccentricity-paced transient hyperthermal events coincided with intense episodes of deep-water acidification and deoxygenation. The in-phase coherence of δ18O and δ13C at the eccentricity band further suggests that orbitally paced processes such as remineralization of organic carbon from the deep-ocean dissolved organic carbon pool and/or weathering-induced carbon and nutrient fluxes from tropical monsoonal regions to the ocean contributed to the high amplitude variability of the marine carbon cycle. Stepwise global cooling and ice-sheet expansion during the middle Miocene climate transition (ca. 14.7–13.8 Ma) were associated with dampening of astronomically driven climate cycles and progressive steepening of the δ13C gradient between intermediate and deep waters, indicating intensification and vertical expansion of ocean meridional overturning circulation following the end of the Miocene climate optimum. Together, these results underline the crucial role of the marine carbon cycle and low-latitude processes in driving climate dynamics on an almost ice-free Earth.
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Stephen, Alistair M., Peter W. Linder y Shirley C. Churms. "Calcium-dependent solubility and rheological properties of some plant polysaccharides". En Gums and stabilisers for the Food industry 6, 149–54. Oxford University PressOxford, 1992. http://dx.doi.org/10.1093/oso/9780199632848.003.0021.
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Abstract Extraction of pectic material from the leaves of Aloe ferox is largely dependent on the removal of calcium ions. Juice squeezed from leaf, and hot-water extracts of the residual pulp, contain mineral salts and polysaccharides low in uronic acid residues. Treatment with aqueous oxalate, citrate or phosphate permits the extraction from pulp of good yields of polysaccharide that forms viscous solutions and, on restoration of Ca2+ ion, gels. Dialysis of the ammonium salt of the pectic polysaccharide ( 50% -GalEA content) against flowing tap water yielded a gel inside the membrane, the metal ion content of which, in comparison with that in the exterior aqueous medium, showed the relative selectivity coefficients for Ca:Mg:Na:K to be in the approximate ratio 100:20:7:20. Further dialysis against distilled water lowered the percentages of ions present in dried gel to Ca2+ 8.7, Mg2+ 0.14, Na+ 0.32 and K+ 0.23. Steric-exclusion chromatography showed a value of 40 000 for the molecular weight of the soluble pectic salt, raised to 330 000 on addition of Ca2+; this was followed by gel formation. Exudate from Cycad cones, a mannoglucuronoglycan with ramified acidic rhamnoarabinogalactan attached to Man in the core, consists of a weak gel from which a low molecular weight (10 000) fraction is extractable with aqueous ethanol. The residual gel is readily dispersed in aqueous sodium carbonate and then has mol. wt. 180 000, not increased on Ca2+ addition although viscosity lowering does result. The solution properties of the two types of polysaccharide, which resemble those of Khaya grandifoliola gum and gum ghatti respectively, are dependent on the relative dispersions of uronic acid groups in the different molecular structures.
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Morowitz, Harold J. "The Litmus Test". En Entropy and the Magic Flute, 165–68. Oxford University PressNew York, NY, 1993. http://dx.doi.org/10.1093/oso/9780195081992.003.0036.
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Abstract IT’S DIFFICULT TO READ through a newspaper these days without encountering reference to a litmus test. Whether the article deals with appointing a Supreme Court justice or the director of the National Institutes of Health, the notion of such a test keeps working its way into the political rhetoric. To those of us who first encountered litmus in cherished childhood chemistry sets, the notion of a political litmus test impinges on the psyche in a strange way. Obviously, a more detailed understanding of litmus is called for. It begins, appropriately enough, with the 1911 edition of Encyclopaedia Britannica: LITMUS (apparently a corruption of lacmus, Dutch lacmoes, lac, lac, and moes, pulp, due to association with “lit,” an obsolete word for dye, colour; the Ger. equivalent is Lackmus, Fr. tournesol), a colouring matter which occurs in commerce in the form of small blue tablets, which, however, consist mostly, not of the pigment proper, but of calcium carbonate and sulphate and other matter devoid of tinctorial value. Litmus is extensively employed by chemists as an indicator for the detection of free acids and free alkalis. An aqueous infusion of litmus, when exactly neutralized by an acid, exhibits a violet colour, which by the least trace of free acid is changed to red, while free alkali turns it to blue. The reagent is generally used in the form of test paper bibulous paper dyed red, purple or blue by the respective kind of infusion. Litmus is manufactured in Holland from the same kinds of lichens (species Roccella and Lecanora) as are used for the preparation of archil.
Actas de conferencias sobre el tema "Carbonate pump"
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Yao, C. Y., N. C. Hill y D. A. McVay. "Economic Pilot-Floods of Carbonate Reservoirs Using a Pump-Aided Reverse Dump-Flood Technique". En SPE Mid-Continent Operations Symposium. Society of Petroleum Engineers, 1999. http://dx.doi.org/10.2118/52179-ms.
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Uniyal, Rishabh, Suman Kumar Jaruhar, Manoj Kumar Sarkar, Sagun Devshali, Dibyajyoti Parida, Sushil Bhoye, Sudipta Biswas y Dhiraj Dodda. "Key Takeaways from Implementing a Successful Downhole Scale Mitigation & Prevention Job in an Indian Western Offshore ESP Well". En Offshore Technology Conference Brasil. OTC, 2023. http://dx.doi.org/10.4043/32764-ms.
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Abstract Multiple ESP wells in an Indian Offshore Carbonate reservoir were afflicted with inorganic scale deposition chronically. Analysis of recovered deposit samples was carried out and the root cause of deposition established. This was followed by successfully carrying out remedial operations for scale removal and prevention. The experience gained from the same has been elaborated in the paper. Inorganic scale deposition in Electrical Submersible Pumps has been a big cause of concern in many wells of a carbonate reservoir in Indian Offshore. Scale deposition in ESPs causes decrease in pump efficiency and sometimes, complete choking and ultimate failure. As part of this study, a detailed Compositional Analysis of recovered samples retrieved from inside the ESP was carried out. Based on the analysis, custom job plans were formulated to clear the scale from within the ESPs and its vicinity. This was followed by a continuous inhibitor injection program from a downhole chemical injection mandrel after the selection of the appropriate chemical. The results of the compositional analysis of the recovered debris showed that despite the well operating in a carbonate reservoir, the majority of the sample was acid-insoluble sulphate scale. Further probing elucidated the fact that multiple acid washes had been performed in the well, which while dissolving the carbonates, left behind insoluble sulphates as residual scale. The operating conditions inside the pump were also especially conducive for sulphate deposition. As such, tailored job plans consisting of a formulation of a chelating agent in an alkaline solution were designed and executed. Implementation of the job plans resulted in significant oil gain from the affected wells and the continuous inhibitor injection has further improved the efficiency of the ESPs and reduced the frequency of cleaning jobs required. The paper aims at providing an insight into inorganic scale deposition in ESPs. After analysing the scaling problem and establishing the root cause, mitigating measures have been devised and implemented. The paper provides a holistic approach towards tackling the problem of existing inorganic scale and preventing future deposition from taking place. The experiences gained during the entire exercise have been deliberated in the paper.
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Ali, Mahmoud T. "Reducing Carbon Footprint of Matrix Acidizing in Carbonate Formations. How Much Acid Do We Really Need to Pump?" En SPE EuropEC - Europe Energy Conference featured at the 83rd EAGE Annual Conference & Exhibition. SPE, 2022. http://dx.doi.org/10.2118/209673-ms.
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Abstract With uncertain global economic conditions and calls for lowering carbon footprint, optimizing carbonate matrix acidizing along with other operations is crucial for operators and services companies. Accurate modeling of wormhole growth is inevitable to optimize acid placement in the field. In this study, a field-scale carbonate acidizing model tuned and validated against 600+ linear and radial experiments is presented to optimize/improve field treatments. Unlike previous semi-empirical models, this model presents the wormhole velocity as a function of Darcy's velocity. This model was validated against a huge number of linear HCl experiments with various temperatures, acid concentrations, rock types, and core dimensions. Both internal and published data were used. The upscaling from linear to radial flow was based on changing the flow area and the number of wormholes as a function of acid progression in the formation. The upscaled model was validated against radial experiments and field observations. The results show that the model can accurately predict acid performance under field conditions. The results of this model have revealed that limestone and dolomite formations can be stimulated using HCl acid volumes as low as 50 gal/ft. For limestone formations, low volume acidizing operations (50 gal/ft.) can result in skin as low as −3.1 (well-flow efficiency (WFE) of 1.6). On the other hand, moderate-high volume acidizing operations (100 gal/ft.) will result in skin of −3.7 (WFE of 1.8). The effect of temperature on the performance increases as the volume of the injected acid increased. At very low injection rates (long horizontals/ low Kh zones), pumping 100 gal/ft. will create 5 ft. long and 2 ft. long wormhole at 100°F and 300°F, respectively. For the dolomite formations, pumping 50 gal/ft. of 15% HCl at 150°F will result in skin of −2.7 (WFE of 1.5), while pumping 100 gal/ft. will result in skin of −3.1 (WFE of 1.6). At 75°F, the injection of 100 gal/ft. will create short wormhole (2.8 ft.) in dolomite and long wormhole (12.6) in limestone. This is because the acidizing process is reaction rate limited at low temperature dolomite. This paper presents a new carbonate matrix acidizing model to optimize carbonate acidizing field treatments. Carbonate wells can be stimulated using low acid volumes with little effect on well performance. That will reduce both the cost and the carbon footprint of those operations.
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Muklas, Aliefiyan Nursanda, Candra Kurniawan, Hendra Kusuma, Bonni Ariwibowo, Prayudha Rifqi Safiraldi y Nayesha Shafira Elthaf Elthaf. "Long Exposure Chelating Acid Treatment to Release ESP Stuck Pump". En SPE/IATMI Asia Pacific Oil & Gas Conference and Exhibition. SPE, 2021. http://dx.doi.org/10.2118/205628-ms.
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Abstract In October 2019, electrical submersible pump (ESP) XY-107 experienced an overload shutdown. Troubleshooting actions have been conducted such as reverse rotation, used rocking method, voltage boost, inject gas through the annulus, and even fluid circulation, yet still failed to reactivate the well. Pump stuck condition was suspected and urgently need a solution. A study was performed to determine the cause of pump stuck. XY-107 is produced from limestone formation, therefore suggesting possibility of scale deposit formation in this well. Upon physical inspection inside the well's flowline, lump of deposit was recovered and suspect similar material could have occurred inside the pump. Rig intervention is a common solution for the ESP pump stuck condition. However, it required high cost (around 80,000 USD) and a longer well service job period up to 5 days. With scale deposit as the suspect, an unconventional solution was proposed to soak the well with acid to dissolve stuck-material by rigless operation. It was much cheaper than rig intervention (only about 4,000 USD) and with a shorter time of 1 day. Yet, acid selection is critical to avoid material damage during operation. Since conventional acid system is known to be corrosive to the metal components, hazardous, and difficult to handle; chelating acid was chosen as an alternative since it is known as a metal-friendly and able to dissolve carbonate and iron deposit. Treatment to address pump stuck situation was executed in March 2020. The chemical treatment was injected by pumping and circulating chelating solution from tubing to the annulus. ESP then soaked for 48-hours long. The treatment has successfully revived the well. It produced with no significant issue for 8 months and even double the oil production. This successful treatment proves chelating technique is safer for ESP and able to regain well production. Significant cost saving up to 76,000 USD was realized by avoiding rig intervention and shortening time of well services. Detailed study, laboratory testing, treatment procedure, and further analysis are discussed in this paper. Chelating acidizing is an uncommon acid system to stimulate carbonates and sandstone in our operating area. Since its successful performance during the trial, more acid campaign using chelating was conducted to enhance oil production. However, this acid system was never been tried as a solution treatment for pump stuck condition and the case of well XY-107 was the first time in the company's history.
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Shehata, Alaaeldin Abdelazim, Emad Nabil, Wael Hassan, Hesham Aql y Salah Kamal. "Progressing Cavity Pump Challenges in Issaran Heavy Oil fracture carbonate reservoir: Case Study Issaran Field, Eastern Desert, Egypt". En North Africa Technical Conference and Exhibition. Society of Petroleum Engineers, 2012. http://dx.doi.org/10.2118/150299-ms.
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Al-Hosni, F. y G. H. Lanier. "Novel Jet-Pump Application Enables Water Flood Project for a Sour Carbonate Reservoir in the Sultanate of Oman". En SPE Artificial Lift Conference and Exhibition. Society of Petroleum Engineers, 2012. http://dx.doi.org/10.2118/163114-ms.
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Harrasi, Mohammed Talib Said Al, Alireza Kazemi, Rami Al-Hmouz, Abdulrahman Aal Abdulsalaam y Rashid Al Hajri. "Machine Learning Techniques for Inorganic Scale Precipitation Prediction: A Real Field Data from a Carbonate Reservoir". En SPE Conference at Oman Petroleum & Energy Show. SPE, 2024. http://dx.doi.org/10.2118/218796-ms.
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Abstract The precipitation of inorganic scales in the oil and gas industry has been identified as a major issue for flow assurance and the optimization of oil and gas fields due to the damage that these precipitations can cause in reservoirs, well completions, and surface facilities. On the other hand, predicting these precipitations has always been challenging for engineers of petroleum, production, and production facilities. Although many commercial computer programs in the industry can predict inorganic scale precipitations with some accuracy, the majority have many limitations that can negatively impact prediction performance. Machine learning (ML) has received substantial attention in the oil and gas industry in recent years. The purpose of this study is to investigate the use of machine learning algorithms as a new approach to predicting inorganic scale precipitations in oil and gas carbonate formations. The methodology of the current study consists of gathering input and output data, such as pressure, temperature, artificial lifting type, target formation, water ionic composition, pH, TDS, and whether or not each well tends to precipitate the inorganic scale. The algorithms chosen for prediction are Naive Bayes (NA), Neural Network classifier (NN), Logistic Regression (LR), Random Forest (RF), Decision Tree (DT), Support Vector Machine (SVM), and K- Nearest Neighbors (KNN), and they will be evaluated based on accuracy and other classification performance metrics. The results of the models show that SVM, DT, and KNN are the best classifiers in terms of prediction accuracy scores with around 83%. Furthermore, a decision tree chart was created based on the Decision Tree (DT) model and can be used to examine the scale precipitation tendency for any future water sample. The chart is validated using real well cases from the same field, demonstrating a match between the predicted class (the well possesses or does not possess a high potential to precipitate inorganic scale) and the data collected in the well's interventions history reports. Based on the DT model, the artificial lifting method, target formation, pressure at the pump depth, and SO42-, HCO3- ionic compositions are found to be the strongest features that play a significant role in the scale precipitations in the studied field. Implementing the proposed model will lead to many benefits, including properly employed well intervention resources, reduced oil deferment due to pump failures caused by scale precipitation, and reduced budget overspending entailed by unexpected failures in pumps, valves, or even surface facilities.
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Samouei, Hamidreza, Igor Ivanishin y Abdollah Orangi. "Novel Class of Retarded, Newtonian, Single-Phase HCl-Based Stimulation Fluids: A Laboratory Characterization". En SPE International Conference and Exhibition on Formation Damage Control. SPE, 2022. http://dx.doi.org/10.2118/208813-ms.
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Abstract Novel retarded acids were designed and evaluated by measuring their dissolution and corrosion rates in the laboratory at a temperature of 250°F. Results indicate that depending on the type of the retarder, the acid solutions containing 15 wt% HCl react 1.2–10.7 slower than 15 wt% straight HCl. In addition, novel retarded acids pass the industry standard for corrosion rate of L80, P110, T95, and 13Cr steel grades even with no corrosion inhibitor added to the formulation. Field application of the novel acid systems will provide a series of benefits, including ease to mix and pump, operational safety, deep stimulation of target zone, etc. Presented results are integral for designing the stimulation operations in carbonate reservoirs and the removal of carbonate scales in the oil and gas or geothermal energy industries.
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Nawal, Aamri, Ghadani Adnan, Crampin Tom y Bos Robert. "Front End Maturation of Thermal Electrical Submersible Pump Design in a Steam Development in the North Oman". En ADIPEC. SPE, 2023. http://dx.doi.org/10.2118/216805-ms.
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Abstract Habur Project will be the second fractured carbonate reservoir using Thermally Assisted Gas Oil Gravity Drainage (TAGOGD) recovery mechanism in Northern Oman. ESPs are selected to provide artificial lift ahead of gas lift to reduce Capex, lower power consumption and to increase well lifting potential. This paper summarizes the approach used to mitigate risks in the deployment of thermal ESPs in potentially extreme corrosive (high H2S and CO2) operating conditions. The ESP operating environment is predicted to be challenging due to a unique combination of conditions: i) high temperature (> 150degC), ii) high free gas/steam production, iii) corrosive with high H2S/CO2. These challenges pose a risk that the pumps are not able to achieve required functionality and/or have a short lifespan. Front-end integrated mitigation plan of the above has been constructed based on i) internal and external ESP performance benchmarking, ii) early detailed "bespoke" thermal ESP design options, iii) initial operating procedures and iv) troubleshooting guidance. Additionally, the project economic robustness was tested against different ESP run life scenarios. Thermal ESPs are a mature artificial lift method with local and global deployment in hot environments such as Steam Assisted Gravity Drainage (SAGD) systems. If steam breakthrough is not appropriately managed, it can result in low pump efficiency or gas lock in some cases which has a negative impact on production. Experience from SAGD in Canada indicates that with proper ESP design and appropriate trouble shooting procedures, risks related to gas and steam breakthrough can be managed. Corrosion can lead to premature ESP failure. Habur Project is predicted to become sour as the rock and reservoir fluids heat up releasing significant CO2 and H2S. However, the risk of corrosion can be mitigated by appropriate material selection of ESP components. Expensive metallurgy raises the cost of pump deployment, but economic analysis shows the project to be robust even in the scenario of short ESP lifespans. This project demonstrates how through benchmarking, multidiscipline integration and early collaboration with ESP service providers supported maturation of a robust ESP design to support project Final Investment Decision. Importantly this work expands the operating conditions of thermal ESPs beyond typical clastic SAGD such as Canada to more corrosive environments expected in carbonate steam developments. Novel workflows described in this paper can be adapted to other challenging high temperature and corrosive fields using TAGOGD or other thermal recovery methods.
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Sidek, Sulaiman, Bahrom Madon y Mohd Zaidi Jaafar. "Lesson Learned from the Application of Calcium Carbonate Polymer for Water Shut-Off Project in A Carbonate Gas Well, Offshore Borneo Island". En SPE Annual Technical Conference and Exhibition. SPE, 2022. http://dx.doi.org/10.2118/210047-ms.
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Abstract This paper provides valuable insights on the systematic engineering approach, extensive laboratory evaluation and lesson learned on the application of calcium carbonate polymer for water shut-off (WSO) project in a carbonate gas well, offshore Borneo Island, East Malaysia. Excessive water production is a well-known problem faced by petroleum industry, combine with carbonate reservoirs that are notoriously difficult to characterize and challenging to produce, the selection of suitable WSO method is vital to ensure successful and sustainable treatment. However, limited studies have been conducted to compare between various chemical WSO from the industry guidelines with the success rate and lesson learned from historical field execution particularly for carbonate gas reservoirs in Malaysia. Carbonate gas reservoirs have long been an important element of Malaysia’s O&G business and as the portfolio increases to meet regional energy demand, focus on effective WSO treatment for carbonate gas wells is crucial in ensuring continuous production delivery to the customers. As a result, study was initiated to evaluate feasibility of WSO using calcium carbonate polymer in a carbonate gas field that has been producing for almost 25 years with nonuniform strong aquifer support and experiencing excessive water production. The workflow adopted for the WSO treatment involves thorough reservoir review to ascertain the water production caused, extensive laboratory testing that include core flood experiments to ascertain the chemical effectiveness, detail field historical production data analysis performance analysis (e.g. nodal analysis and network modeling), sensitivity analysis on fluid placement using CAD software (e.g. StimPro), economic evaluation that include decision risk analysis to evaluate all range of probabilistic outcome along with a structured post-job review on the failure analysis. Laboratory testing and core flooding was conducted to mimic the condition during mixing at surface, pumping into the well and the soaking in the reservoir, from 80degf at 14.7psi and to 245degF up at 1700psi. Building the model for WSO candidates requires well calibration and matching to the current well performance to ensure correct basis of evaluation, hence Prosper was used as a tool for nodal analysis for multilayer model to analyze the zone contribution, estimate the gas production gain and determine water production reduction. Chemical placement and volume were generated using StimPro considering several case scenarios that include coiled tubing placement, optimum injection rate and ideal penetration depth. Based on the laboratory test results, the calcium carbonate polymer can be pump through the CT (e.g. total gelling time of 48hrs including mixing, POOH CT & soaking). Core flooding indicate that it can be pumped into the reservoir & withstand up to 1700 psi forward pressure. Fluid placement was generated using StimPro where it was recommended to use retrievable packer to minimize the risk of calcium carbonate polymer invasion into the gas producing zone. Post-job review suggests additional test to mimic all possible scenarios on-site particularly temperature sensitivity to determine gelling time and gel stability correspond to various pumping time and rates. This paper highlighted the potential of WSO using calcium carbonate polymer for the candidate well and will be applicable as evident of practical improvement for the WSO treatment execution in the future. Change in business landscapes may be observed toward chemical WSO should the application is successful to maximize Asset value within PETRONAS that experiencing similar issue.
Informes sobre el tema "Carbonate pump"
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Delwiche, Michael, Boaz Zion, Robert BonDurant, Judith Rishpon, Ephraim Maltz y Miriam Rosenberg. Biosensors for On-Line Measurement of Reproductive Hormones and Milk Proteins to Improve Dairy Herd Management. United States Department of Agriculture, febrero de 2001. http://dx.doi.org/10.32747/2001.7573998.bard.
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The original objectives of this research project were to: (1) develop immunoassays, photometric sensors, and electrochemical sensors for real-time measurement of progesterone and estradiol in milk, (2) develop biosensors for measurement of caseins in milk, and (3) integrate and adapt these sensor technologies to create an automated electronic sensing system for operation in dairy parlors during milking. The overall direction of research was not changed, although the work was expanded to include other milk components such as urea and lactose. A second generation biosensor for on-line measurement of bovine progesterone was designed and tested. Anti-progesterone antibody was coated on small disks of nitrocellulose membrane, which were inserted in the reaction chamber prior to testing, and a real-time assay was developed. The biosensor was designed using micropumps and valves under computer control, and assayed fluid volumes on the order of 1 ml. An automated sampler was designed to draw a test volume of milk from the long milk tube using a 4-way pinch valve. The system could execute a measurement cycle in about 10 min. Progesterone could be measured at concentrations low enough to distinguish luteal-phase from follicular-phase cows. The potential of the sensor to detect actual ovulatory events was compared with standard methods of estrus detection, including human observation and an activity monitor. The biosensor correctly identified all ovulatory events during its testperiod, but the variability at low progesterone concentrations triggered some false positives. Direct on-line measurement and intelligent interpretation of reproductive hormone profiles offers the potential for substantial improvement in reproductive management. A simple potentiometric method for measurement of milk protein was developed and tested. The method was based on the fact that proteins bind iodine. When proteins are added to a solution of the redox couple iodine/iodide (I-I2), the concentration of free iodine is changed and, as a consequence, the potential between two electrodes immersed in the solution is changed. The method worked well with analytical casein solutions and accurately measured concentrations of analytical caseins added to fresh milk. When tested with actual milk samples, the correlation between the sensor readings and the reference lab results (of both total proteins and casein content) was inferior to that of analytical casein. A number of different technologies were explored for the analysis of milk urea, and a manometric technique was selected for the final design. In the new sensor, urea in the sample was hydrolyzed to ammonium and carbonate by the enzyme urease, and subsequent shaking of the sample with citric acid in a sealed cell allowed urea to be estimated as a change in partial pressure of carbon dioxide. The pressure change in the cell was measured with a miniature piezoresistive pressure sensor, and effects of background dissolved gases and vapor pressures were corrected for by repeating the measurement of pressure developed in the sample without the addition of urease. Results were accurate in the physiological range of milk, the assay was faster than the typical milking period, and no toxic reagents were required. A sampling device was designed and built to passively draw milk from the long milk tube in the parlor. An electrochemical sensor for lactose was developed starting with a three-cascaded-enzyme sensor, evolving into two enzymes and CO2[Fe (CN)6] as a mediator, and then into a microflow injection system using poly-osmium modified screen-printed electrodes. The sensor was designed to serve multiple milking positions, using a manifold valve, a sampling valve, and two pumps. Disposable screen-printed electrodes with enzymatic membranes were used. The sensor was optimized for electrode coating components, flow rate, pH, and sample size, and the results correlated well (r2= 0.967) with known lactose concentrations.