Bibliographies thématiques / Silicon cycle

Littérature scientifique sur le sujet « Silicon cycle »

Auteur : Grafiati
Publié le 20 avril 2024

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Articles de revues sur le sujet "Silicon cycle"

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Ittekkot, Venugopalan, Lars Rahm, Dennis P. Swaney et Christoph Humborg. « Perturbed silicon cycle discussed ». Eos, Transactions American Geophysical Union 81, no 18 (2000) : 198. http://dx.doi.org/10.1029/00eo00135.

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Wang, Jing, Xiao Hang Yang, Yue Feng Su, Shi Chen et Feng Wu. « Effect of Fluorine-Containing Additive on the Electrochemical Properties of Silicon Anode for Lithium-Ion Batteries ». Materials Science Forum 944 (janvier 2019) : 699–704. http://dx.doi.org/10.4028/www.scientific.net/msf.944.699.

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Silicon anode is a promising candidate as an alternative to the conventional graphitic anode in lithium-ion batteries. In this work, silicon anode is modified by NH4F using a facile method in air. The concentration of NH4F on the electrochemical performance is systematically checked. The 5wt%NH4F-modified silicon anode exhibits enhanced cycle and rate performances, the first discharge specific capacity is 3958 mAh·g-1 with 86.45% as the coulombic efficiency at 0.4A·g-1. The capacity can maintain at 703.3 mAh·g-1 after 50 cycles, exhibiting a much better cycle stability than pristine silicon anode (329.9 mAh·g-1 after 50 cycles). SEM images confirm that NH4F can alleviate the volume expansion of silicon since LiF can be generated at the surface which is beneficial to the stability of solid-electrolyte interphase (SEI).
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Struyf, Eric, Adriaan Smis, Stefan Van Damme, Patrick Meire et Daniel J. Conley. « The Global Biogeochemical Silicon Cycle ». Silicon 1, no 4 (octobre 2009) : 207–13. http://dx.doi.org/10.1007/s12633-010-9035-x.

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Ikeda, Takeshi. « Bacterial biosilicification : a new insight into the global silicon cycle ». Bioscience, Biotechnology, and Biochemistry 85, no 6 (20 avril 2021) : 1324–31. http://dx.doi.org/10.1093/bbb/zbab069.

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ABSTRACT Biosilicification is the process by which organisms incorporate soluble, monomeric silicic acid, Si(OH)4, in the form of polymerized insoluble silica, SiO2. Biosilicifying eukaryotes, including diatoms, siliceous sponges, and higher plants, have been the targets of intense research to study the molecular mechanisms underlying biosilicification. By contrast, prokaryotic biosilicification has been less well studied, partly because the biosilicifying capability of well-known bacteria was not recognized until recently. This review summarizes recent findings on bacterial extracellular and intracellular biosilicification, the latter of which has been demonstrated only recently in bacteria. The topics discussed herein include bacterial (and archaeal) extracellular biosilicification in geothermal environments, encapsulation of Bacillus spores within a silica layer, and silicon accumulation in marine cyanobacteria. The possible contribution of bacterial biosilicification to the global silicon cycle is also discussed.
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Koraag, Pierre Yosia Edward, Arief Muhammad Firdaus, Naufal Hanif Hawari, Andam Deatama Refino, Wibke Dempwolf, Ferry Iskandar, Erwin Peiner, Hutomo Suryo Wasisto et Afriyanti Sumboja. « Covalently Bonded Ball-Milled Silicon/CNT Nanocomposite as Lithium-Ion Battery Anode Material ». Batteries 8, no 10 (7 octobre 2022) : 165. http://dx.doi.org/10.3390/batteries8100165.

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The demand for high-capacity lithium-ion batteries (LIBs) is ever-increasing. Thus, research has been focused on developing silicon-based anodes due to their high theoretical capacity and natural abundance. However, silicon-based anodes still suffer from several drawbacks (e.g., a huge volume expansion during lithiation/delithiation and the low conductivity nature of silicon). In this study, we develop a facile and low-cost synthesis route to create a composite of silicon particles and carbon nanotubes (CNTs) via simple two-step mechanical ball milling with a silicon wafer as the silicon precursor. This method produces a strong interaction between silicon particles and the CNTs, forming Si–C bonds with minimum oxidation of silicon and pulverization of the CNTs. The resulting Si/CNT anode exhibits a first cycle Coulombic efficiency of 98.06%. It retains 71.28% of its first cycle capacity of 2470 mAh g−1 after 100 cycles of charge–discharge at a current density of 400 mA g−1. Furthermore, the Si/CNT anode also shows a good rate capability by retaining 80.15%, and 94.56% of its first cycle capacity at a current density of 1000 mA g−1 and when the current density is reduced back to 200 mA g−1, respectively.
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Chan, Kwai S., Michael A. Miller, Carol Ellis-Terrell et Candace K. Chan. « Synthesis and Characterization of Empty Silicon Clathrates for Anode Applications in Li-ion Batteries ». MRS Advances 1, no 45 (2016) : 3043–48. http://dx.doi.org/10.1557/adv.2016.434.

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ABSTRACTSeveral processing methods were developed and evaluated for synthesizing empty silicon clathrates. A solution synthesis method based on the Hofmann-elimination oxidation reaction was successfully utilized to produce 20 mg of empty Si46. Half-cells using the Si46 electrodes were successfully cycled for 1000 cycles at rate of 5.3C. The capacity of the Si46 electrode in long-term tests was 675 mAh/g at the 4th cycle, but increased to 809 mAh/g at 50 cycles. The corresponding Coulombic efficiency was better than 99%. The capacity dropped from 809 to 553 mAh/g after 1000 cycles while maintaining a 99% Coulombic efficiency. In comparison, a Ba8Al8Si38 electrode could be cycled for about 200 cycles with a lower capacity and Coulombic efficiency. Potential applications of empty silicon clathrates as anode materials in Li-ion batteries are discussed.
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de Tombeur, F., B. L. Turner, E. Laliberté, H. Lambers, G. Mahy, M. P. Faucon, G. Zemunik et J. T. Cornelis. « Plants sustain the terrestrial silicon cycle during ecosystem retrogression ». Science 369, no 6508 (3 septembre 2020) : 1245–48. http://dx.doi.org/10.1126/science.abc0393.

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The biogeochemical silicon cycle influences global primary productivity and carbon cycling, yet changes in silicon sources and cycling during long-term development of terrestrial ecosystems remain poorly understood. Here, we show that terrestrial silicon cycling shifts from pedological to biological control during long-term ecosystem development along 2-million-year soil chronosequences in Western Australia. Silicon availability is determined by pedogenic silicon in young soils and recycling of plant-derived silicon in old soils as pedogenic pools become depleted. Unlike concentrations of major nutrients, which decline markedly in strongly weathered soils, foliar silicon concentrations increase continuously as soils age. Our findings show that the retention of silicon by plants during ecosystem retrogression sustains its terrestrial cycling, suggesting important plant benefits associated with this element in nutrient-poor environments.
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Ma, Kai. « Silicon-Based Anode with High Capacity and Performance Produced by Magnesiothermic Coreduction of Silicon Dioxide and Hexachlorobenzene ». Journal of Electrochemical Science and Technology 12, no 3 (31 août 2021) : 317–22. http://dx.doi.org/10.33961/jecst.2020.01662.

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Silicon (Si) has been considered as a promising anode material because of its abundant reserves in nature, low lithium ion (Li+) intercalation/de-intercalation potential (below 0.5 V vs. Li/Li+) and high theoretical capacity of 4200 mA h/g. In this paper, we prepared a silicon-based (Si-based) anode material containing a small amount of silicon carbide by using magnesiothermic coreduction of silica and hexachlorobenzene. Because of good conductivity of silicon carbide, the cycle performance of the silicon-based anode materials containing few silicon carbide is greatly improved compared with pure silicon. The raw materials were formulated according to a silicon-carbon molar ratio of 10:0, 10:1, 10:2 and 10:3, and the obtained products were purified and tested for their electrochemical properties. After 1000 cycles, the specific capacities of the materials with silicon-carbon molar ratios of 10:0, 10:1, 10:2 and 10:3 were still up to 412.3 mA h/g, 970.3 mA h/g, 875.0 mA h/g and 788.6 mA h/g, respectively. Although most of the added carbon reacted with silicon to form silicon carbide, because of the good conductivity of silicon carbide, the cycle performance of silicon-based anode materials was significantly better than that of pure silicon.
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Fu, Qiang Wei, et Xun Yong Jiang. « Lithium Storage Property of Metallic Silicon Treated by Mechanical Alloying ». Materials Science Forum 847 (mars 2016) : 29–32. http://dx.doi.org/10.4028/www.scientific.net/msf.847.29.

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Theoretical capacity of silicon is 4200mAhg-1, but pure silicon had huge volume change during lithium insertion, which reduces the cycle life of silicon. In this paper, pure silicon was replaced of metallic silicon to relieve volume effect. Metallic silicon contains some alloying elements which improve the conductivity of the electrode material. The elements in metallic silicon will relief the volume change of silicon substrate during lithium insertion/ de-lithiation process. Metallic silicon was treated by mechanical alloying (MA) which is an effective method to reduce particle sizes of metallic silicon. The results show that MA can improve cycle performance of metallic silicon. Metallic silicon treated by MA performs a better cycling performance compared with the unsettled materials and a higher discharge capacity in the first cycle.
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Sarracino Martínez, O., J. Escorcia-Garcia, J. M. Gracia-Jiménez et V. Agarwal. « Photoluminescent Photonic Devices from Nanostructured Porous Silicon Fabricated Using Lightly Doped Silicon ». Journal of Nano Research 4 (janvier 2009) : 11–17. http://dx.doi.org/10.4028/www.scientific.net/jnanor.4.11.

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In this work, we report the fabrication of porous silicon multilayers using lightly doped, p-type, silicon wafers (resistivity: 14-22 Ω-cm) by pulsed anodic etching. The optical properties have been found to be strongly dependent on the duty-cycle and frequency of the applied current. Less than 50 % of duty-cycle, at low frequencies, is found to show very rough porous silicon – crystalline silicon (PS-cSi) interface. Use of duty cycle above 50 %, in a certain range of frequencies, is found to make the interface smooth. The optical properties of the photonic devices are investigated for 50 % and 75 % of duty-cycle, for different frequencies in the range of 0-1000 Hz, using the current densities of 10, 90 and 150 mA/cm2. The possibility of fabricating rugate filter with this resistivity is also explored.
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Thèses sur le sujet "Silicon cycle"

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Neu, Silke, Jörg Schaller et E. Gert Dudel. « Silicon availability modifies nutrient use efficiency and content, C:N:P stoichiometry, and productivity of winter wheat (Triticum aestivum L.) ». Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-221008.

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Silicon (Si) is known as beneficial element for graminaceous plants. The importance of Si for plant functioning of cereals was recently emphasized. However, about the effect of Si availability on biomass production, grain yield, nutrient status and nutrient use efficiency for wheat (Triticum aestivum L.), as one of the most important crop plants worldwide, less is known so far. Consequently, we assessed the effect of a broad range of supply levels of amorphous SiO2 on wheat plant performance. Our results revealed that Si is readily taken up and accumulated basically in aboveground vegetative organs. Carbon (C) and phosphorus (P) status of plants were altered in response to varying Si supply. In bulk straw biomass C concentration decreased with increasing Si supply, while P concentration increased from slight limitation towards optimal nutrition. Thereby, aboveground biomass production increased at low to medium supply levels of silica whereas grain yield increased at medium supply level only. Nutrient use efficiency was improved by Si insofar that biomass production was enhanced at constant nitrogen (N) status of substrate and plants. Consequently, our findings imply fundamental influences of Si on C turnover, P availability and nitrogen use efficiency for wheat as a major staple crop.
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Fripiat, François. « Isotopic approaches in the silicon cycle : the Southern Ocean case study ». Doctoral thesis, Universite Libre de Bruxelles, 2010. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210187.

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We investigate the silicon (Si) cycle in the Southern Ocean through two isotopic approaches: (1) 30Si-incubation experiments and (2) natural silicon isotopic composition (ä30Si). 30Si-spiked incubation allows to discriminate the short-term (~ 1 day) net Si-uptake flux in bSiO2 production and dissolution. ä30Si of both biogenic silica and dissolved silicon integrates at seasonal/annual scale bSiO2 production or dissolution and mixing.

(1) A new mass spectrometer method (HR-SF-ICPMS) has been developed for 30Si-isotopic abundance measurements. This methodology is faster and easier than the previous available methodologies and has the same precision. A complete set of incubation was coupled with parallel 32Si-incubations and the two methodologies give not significantly different bSiO2 production rates. In the Southern Ocean, especially in the southern Antarctic Circumpolar Current, the large silicic acid concentration degrades the sensitivity of the method with Si dissolution fluxes staying generally below the detection limit. In contrast, the 28Si-isotopic dilution was sensitive enough to assess low biogenic silica dissolution rates in silicic acid poor waters of the northern ACC. We show that large accumulation of detrital dissolving biogenic silica after productive period implies really efficient silicon loop with integrated (euphotic layer) dissolution:production ratio equal or larger than 1.

(2) We largely expand the silicic acid isotopic data in the open ocean. Relatively simple mass and isotopic balances have been performed in the Antarctic Zone and have allowed to apply for the first time ä30Si in a quantitative way to estimate regional net silica production and quantify source waters fueling bSiO2 productivity. We observe that at the end of the productive period as suggested with 30Si-incubation, large accumulation of detrital biogenic silica in the surface waters increase the D:P ratio and subsequently dampens the bSiO2 production mediated isotopic fractionation with residual biogenic silica carrying heavier ä30Si than expected. Seasonal isotopic evolution is simulated and seems in agreement with our observations. These simulations strongly suggest working with non-zero order equations to fully assess the seasonal expression of the different processes involved: mixing, uptake, dissolution. Si-isotopes are also tracking the origin and fates of the different ACC pools across the Southern Ocean meridional circulation. Moreover during the circumpolar eastward pathway, the bSiO2 dissolution in deep water decreases the corresponding ä30Si values and this imprint is further transmitted via the upper limb of the meridional circulation in the intermediate water masses.


Doctorat en Sciences
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Frost, Sean. « Applying an environmental life-cycle approach to a silicon photovoltaic system ». Thesis, Frost, Sean (2009) Applying an environmental life-cycle approach to a silicon photovoltaic system. Masters by Coursework thesis, Murdoch University, 2009. https://researchrepository.murdoch.edu.au/id/eprint/2531/.

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Life Cycle Assessment (LCA) is potentially an important decision support tool for the energy sector. This paper explores the effectiveness of the use of LCA in assessing the environmental impacts of photovoltaic (PV) systems, and the value in doing so. LCAs can be used to compare the relative environmental impacts of different products or industrial processes (such as PV-sourced electricity generation), but LCAs generally don’t compare the significance of measured impact levels relative to absolute limits for resource depletion, harmful emissions, and other impacts. In addition, LCAs use varying numbers and types of indicators, sometimes introducing non-scientific value judgements by weighting and aggregating the results. Regardless of these limitations, LCAs sometimes purport to provide a complete environmental assessment and are sometimes regarded as ‘scientific’ in all aspects. In promoting their use, it is important to understand the limitations of environmental accounting methods.
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Neu, Silke, Jörg Schaller et E. Gert Dudel. « Silicon availability modifies nutrient use efficiency and content, C:N:P stoichiometry, and productivity of winter wheat (Triticum aestivum L.) ». Nature Publishing Group, 2016. https://tud.qucosa.de/id/qucosa%3A30213.

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Silicon (Si) is known as beneficial element for graminaceous plants. The importance of Si for plant functioning of cereals was recently emphasized. However, about the effect of Si availability on biomass production, grain yield, nutrient status and nutrient use efficiency for wheat (Triticum aestivum L.), as one of the most important crop plants worldwide, less is known so far. Consequently, we assessed the effect of a broad range of supply levels of amorphous SiO2 on wheat plant performance. Our results revealed that Si is readily taken up and accumulated basically in aboveground vegetative organs. Carbon (C) and phosphorus (P) status of plants were altered in response to varying Si supply. In bulk straw biomass C concentration decreased with increasing Si supply, while P concentration increased from slight limitation towards optimal nutrition. Thereby, aboveground biomass production increased at low to medium supply levels of silica whereas grain yield increased at medium supply level only. Nutrient use efficiency was improved by Si insofar that biomass production was enhanced at constant nitrogen (N) status of substrate and plants. Consequently, our findings imply fundamental influences of Si on C turnover, P availability and nitrogen use efficiency for wheat as a major staple crop.
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Delvigne, Camille. « The Archaean silicon cycle insights from silicon isotopes and Ge/Si ratios in banded iron formations, palaeosols and shales ». Doctoral thesis, Universite Libre de Bruxelles, 2012. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209652.

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The external silicon cycle during the Precambrian (4.5-0.5 Ga) is not well understood despite its key significance to apprehend ancient dynamics at the surface of the Earth. In the absence of silicifying organisms, external silicon cycle dramatically differs from nowadays. Our current understanding of Precambrian oceans is limited to the assumption that silicon concentrations were close to saturation of amorphous silica. This thesis aims to bring new insights to different processes that controlled the geochemical silicon cycle during the Archaean (3.8-2.5 Ga). Bulk rock Ge/Si ratio and Si isotopes (δ30Si) offer ideal tracers to unravel different processes that control the Si cycle given their sensitivity to fractionation under near-surface conditions.

First, this study focuses on Si inputs and outputs to ocean over a limited time period (~2.95 Ga Pongola Supergroup, South Africa) through the study of a palaeosol sequence and a contemporaneous banded iron formation. The palaeosol study offers precious clues in the comprehension of Archaean weathering processes and Si transfer from continent to ocean. Desilication and iron leaching were shown to be the major Archaean weathering processes. The occurrence of weathering residues issued of these processes as major component in fine-grained detrital sedimentary mass (shales) attests that identified weathering processes are widely developed and suggest an important dissolved Si flux from continent to the ocean. In parallel, banded iron formations (BIFs), typically characterised by alternation of iron-rich and silica-rich layers, represent an extraordinary record of the ocean-derived silica precipitation throughout the Precambrian. A detailed study of a 2.95 Ga BIF with excellent stratigraphic constraints identifies a seawater reservoir mixed with significant freshwater and very limited amount of high temperature hydrothermal fluids as the parental water mass from which BIFs precipitated. In addition, the export of silicon promoted by the silicon adsorption onto Fe-oxyhydroxides is evidenced. Then, both Si- and Fe-rich layers of BIFs have a common source water mass and a common siliceous ferric oxyhydroxides precursor. Thus, both palaeosols and BIFs highlight the significance of continental inputs to ocean, generally under- estimated or neglected, as well as the close link between Fe and Si cycles.

In a second time, this study explores secular changes in the Si cycle along the Precambrian. During this timespan, the world ocean underwent a progressive decrease in hydrothermal inputs and a long-term cooling. Effects of declining temperature over the oceanic Si cycle are highlighted by increasing δ30Si signatures of both chemically precipitated chert and BIF through time within the 3.8-2.5 Ga time interval. Interestingly, Si isotope compositions of BIF are shown to be kept systematically lighter of about 1.5‰ than contemporaneous cherts suggesting that both depositions occurred through different mechanisms. Along with the progressive increase of δ30Si signature, a decrease in Ge/Si ratios is attributed to a decrease in hydrothermal inputs along with the development of large and widespread desilication during continental weathering.

Le cycle externe du silicium au précambrien (4.5-0.5 Ga) reste mal compris malgré sa position clé dans la compréhension des processus opérant à la surface de la Terre primitive. En l’absence d’organismes sécrétant un squelette externe en silice, le cycle précambrien du silicium était vraisemblablement très différent de celui que nous connaissons à l’heure actuelle. Notre conception de l’océan archéen est limitée à l’hypothèse d’une concentration en silicium proche de la saturation en silice amorphe. Cette thèse vise à une meilleure compréhension des processus qui contrôlaient le cycle géochimique externe du silicium à l’archéen (3.8-2.5 Ga). Dans cette optique, le rapport germanium/silicium (Ge/Si) et les isotopes stables du silicium (δ30Si) représentent des traceurs idéaux pour démêler les différents processus contrôlant le cycle du Si.

Dans un premier temps, cette étude se focalise sur les apports et les exports de silicium à l’océan sur une période de temps restreinte (~2.95 Ga Pongola Supergroup, Afrique du Sud) via l’étude d’un paléosol et d’un dépôt sédimentaire de précipitation chimique quasi-contemporain. L’étude du paléosol apporte de précieux indices quant aux processus d’altération archéens et aux transferts de silicium des continents vers l’océan. Ainsi, la désilicification et le lessivage du fer apparaissent comme des processus majeurs de l’altération archéenne. La présence de résidus issus de ces processus d’altération en tant que composants majeurs de dépôts détritiques (shales) atteste de la globalité de ces processus et suggère des flux significatifs en silicium dissout des continents vers l’océan. En parallèle, les « banded iron formations » (BIFs), caractérisés par une alternance de niveaux riches en fer et en silice, représentent un enregistrement extraordinaire et caractéristique du précambrien de précipitation de silice à partir de l’océan. Une étude détaillée d’un dépôt de BIFs permet d’identifier une contribution importante des eaux douces dans la masse d’eau à partir de laquelle ces roches sont précipitées. Par ailleurs, un mécanisme d’export de silicium via absorption sur des oxyhydroxydes de fer est mis en évidence. Ainsi, les niveaux riches en fer et riche en silice constituant les BIFs auraient une même origine, un réservoir d’eau de mer mélangée avec des eaux douces et une contribution minime de fluides hydrothermaux de haute température, et un même précurseur commun. Dès lors, tant les paléosols que les BIFs mettent en évidence l’importance des apports continentaux à l’océan, souvent négligés ou sous estimés, ainsi que le lien étroit entre les cycles du fer et du silicium.

Dans un second temps, cette étude explore l’évolution du cycle du silicium au cours du précambrien. Durant cette période, l’océan voit les apports hydrothermaux ainsi que sa température diminuer. Dans l’intervalle de temps 3.8-2.5 Ga, les effets de tels changements sur le cycle du silicium sont marqués par un alourdissement progressif des signatures isotopiques des cherts et des BIFs. Le fort parallélisme entre l’évolution temporelle des compositions isotopiques des deux précipités met en évidence leur origine commune, l’océan. Cependant, les compositions isotopiques des BIFs sont systématiquement plus légères d’environ 1.5‰ que les signatures enregistrées pas les cherts. Cette différence est interprétée comme le reflet de mécanismes de dépôts différents. L’alourdissement progressif des compositions isotopiques concomitant à une diminution des rapports Ge/Si reflètent une diminution des apports hydrothermaux ainsi que la mise en place d’une désilicification de plus en plus importante et/ou généralisée lors de l’altération des continents.


Doctorat en Sciences
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Hughes, Harold. « Si isotopes in tropical rivers as a proxy of the continental silicon cycle ». Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209808.

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Silicon (Si) is one of the most abundant elements in the dissolved phase in rivers and is a key nu-trient in riverine and marine ecosystems. The continental cycle of Si is complex and involves interactions with many secondary reservoirs such as clay minerals and biogenic silica (BSi), making the Si fluxes hard to constrain. Stable isotopes provide a way to trace and describe element cycling. The natural isotopic fractionations that accompany the transfer of the element from one reservoir to another lead to specific isotopic signatures that can be used to reconstruct its source and the pathway during its biogeochemical cycle. The aim of this thesis is therefore to explore the potential of Si isotopes as a tracer of the factors controlling the dissolved Si (DSi) concentration in rivers and more specifically in tropical rivers.

Key issues treated in this thesis are the improvement of our understanding of 1° the spatial and seasonal variability of Si isotopic signatures in rivers, 2° the biological influence on the riverine isotopic signatures and on DSi and BSi fluxes, and 3° the impact of the type of weathering on the riverine isotope signatures.

The isotopic composition of different tropical basins such as the Congo River (Central Africa), the Tana River (Kenya), the Amazon (South America) and its tributaries, were determined along with other physico-chemical parameters. In order to achieve this, the water sample purification processing, necessary before isotope analyses, required specific improvements that are also pre-sented here. The average of all the riverine δ30Si signatures available so far is +1.11 ‰ (n = 253). The impact of diatom growth on the isotopic signatures of the rivers can be clearly shown in the different systems studied, and especially in the Congo River where the isotopic signature could be used in order to estimate the diatom production. The impact of anthropic perturbations through dam construction is also clearly shown in the Tana River. On a global scale the biological influ-ence on the riverine isotopic signatures is estimated to induce an increase of 0.18 ‰ of the δ30Si signature in rivers. This study also confirms the preponderant influence of weathering and secondary clay formation on dissolved Si isotope signatures in the studied rivers. Finally, isotopic signatures from these rivers are compared to data available for other rivers around the world in order to draw large trends on a global scale.

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Le silicium (Si) est l’un des éléments les plus abondants sous forme dissoute dans les rivières et est un nutriment fondamental tant dans les rivières que dans les écosystèmes marins. Le cycle continental du Si est complexe et inclut des interactions avec de nombreux réservoirs secondaires, comme les argiles et la silice biogénique (BSi), rendant les flux de Si difficiles à quantifier. Les isotopes stables fournissent un moyen de tracer et de décrire le cycle d’un élément. Le fractionnement isotopique qui accompagne le transfert de l’élément d’un réservoir à un autre induit des signatures isotopiques spécifiques qui peuvent être utilisées pour retracer la source et la trajectoire suivie par cet élément au cours de son cycle biogéochimique. Le but de cette thèse est d’explorer le potentiel des isotopes du Si en tant qu’indicateur des facteurs contrôlant la concentration en Si dissous (DSi) dans les rivières et plus spécifiquement dans les rivières tropicales.

Les questions principales traitées dans cette thèse sont l’amélioration des connaissances de :1° la variabilité spatiale et saisonnière des signatures isotopiques du Si dans les rivières, 2° l’influence biologique sur les signatures isotopiques des rivières et sur les flux de DSi et BSi et 3° l’impacte du type d’altération sur les signatures isotopiques des rivières.

Les compositions isotopiques de différents bassins tropicaux tels que le Fleuve Congo (Afrique Centrale), le Fleuve Tana (Kenya), l’Amazone (Amérique du Sud) et ses principaux affluents ont été déterminées en même temps que d’autres paramètres physicochimiques. Pour ce faire, le pro-cédé de purification des échantillons d’eau, préalable aux analyses isotopiques, a nécessité des améliorations spécifiques qui sont également présentées ici. La moyenne de toutes les signatures δ30Si accessibles à l’heure actuelle est de +1.11 ‰ (n = 253). L’impact de la croissance des diatomées sur les signatures isotopiques des rivières est démontré dans les différents systèmes étudiés, spécialement pour le Fleuve Congo où la signature isotopique a pu être utilisée afin de déterminer la production de diatomées. L’influence de perturbations anthropiques telles que la construction de barrages a pu être démontrée pour le Fleuve Tana. À l’échelle globale, on estime que l’influence biologique sur la signature isotopique des rivières mène à une augmentation de 0.18 ‰ de la signature δ30Si moyenne des rivières. Cette étude confirme également l’influence prépondérante de l’altération et de la formation d’argiles secondaires sur les signatures isotopiques du DSi dans les rivières étudiées. Enfin, les signatures isotopiques de ces rivières sont comparées aux données accessibles pour d’autres rivières à travers le monde afin d’en déduire les grandes tendance à l’échelle mondiale.


Doctorat en Sciences
info:eu-repo/semantics/nonPublished

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Closset, Ivia. « Le cycle biogéochimique du silicium dans l’Océan Austral par les approches isotopiques ». Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066124/document.

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La biogéochimie de l’Océan austral joue un rôle crucial dans la régulation de la production primaire marine globale en contrôlant la disponibilité des nutriments dans les eaux de surface des basses latitudes. Les variations du cycle du silicium (Si) sont nombreuses et son couplage avec les autres éléments n’est pas encore bien compris dans cet océan. Les résultats issus de deux approches isotopiques différentes suggèrent qu’une pompe de Si active est rapidement initiée au printemps par la transition d’un mode de production de silice biogénique régénéré à une production dite « nouvelle ». L’évolution saisonnière de la composition isotopique naturelle du Si (δ30Si) est principalement contrôlée par l’équilibre entre les rapports « dissolution/production » et « Si-supply/Si-uptake » qui découplent la dynamique isotopique des réservoirs de Si dissout et particulaire (respectivement DSi et BSi). Nous avons également utilisé les mesures de δ30Si pour retracer les flux saisonniers de BSi vers l’océan profond. Ces résultats confirment que le δ30Si n’est pas altéré durant la sédimentation des particules. L’évolution saisonnière du δ30Si a permis de quantifier pour la première fois certains processus contrôlant la production des diatomées et leur devenir, tels que les évènements de mélange alimentant la ML en nutriments, ou l’évolution saisonnière de la vitesse de sédimentation des particules. Ces résultats confirment que le δ30Si du DSi et de la BSi, combinés aux techniques isotopiques de mesure des flux dans la ML, sont des outils prometteurs dans l’amélioration de nos connaissances du cycle du Si et apportent des informations nouvelles à intégrer aux modèles biogéochimiques
Southern Ocean biogeochemistry plays a crucial role on global marine primary production by impacting the nutrient availability even in low latitude surface water. Variations in the silicon (Si) cycle are large and its coupling to other nutrient biogeochemical cycles is still not well understood in this ocean. Results of two different isotopic approaches suggested that a strong silicon pump was quickly initiated in spring by a switch from regenerated to new biogenic silica production. The seasonal evolution of natural Si isotopic composition (δ30Si) was mainly driven by the balance between the “dissolution to production” and “Si-supply to Si-uptake” ratios that decoupled the isotopic dynamics of particulate and dissolved Si-pools (DSi and BSi, repectively). We also used δ30Si measurements to track seasonal flows of BSi to the deep sea with. These results confirmed that the δ30Si is well preserved during particles settling. The seasonal evolution of δ30Si signal allows for the first time to quantify important features about the processes controlling the diatoms’ productivity and its fate, such as mixing events that bring nutrient in the ML or the seasonal evolution of particles sinking velocities. These insights confirm that the δ30Si of DSi and BSi, combined to isotopic technics to measure Si fluxes in the ML, are promising tools to improve our understanding on the Si-biogeochemical cycle and provide new constraints for application to biogeochemical models
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Kameswari, Rajasekaran Mangalaa. « Silicon biogeochemical cycle along the land to ocean continuum : Focus on Indian monsoonal estuaries ». Thesis, Paris 6, 2016. http://www.theses.fr/2016PA066713/document.

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Le silicium est le second élément le plus abondant de la croûte terrestre et un nutriment clefs des écosystèmes aquatiques. Il existe de fortes interactions entre Si, le cycle du carbone et les processus biogéochimiques. Cette étude porte sur la variabilité de Si (amorphe-ASi, lithogène-LSi et dissous-DSi) et les isotopes de Si le long du continuum continent-océan. Nous avons étudié la variabilité saisonnière et spatiale de ASi, LSi, DSi et des isotopes dans ~20 estuaires indiens. Nous avons catégorisé les estuaires selon une analyse statistique (PCA et regroupement). Le prélèvement par les diatomées semble être le principal processus contrôlant ASi en saison sèche, surtout au Sud. L’altération et l’érosion contrôlent LSi dans les autres estuaires. En saison humide, l’impact des diatomées n’est pas observé à cause d’une trop forte charge sédimentaire et tous les estuaires sont dominés par les apports lithogéniques. Les compositions isotopiques de Si peuvent tracer les sources de Si et les interactions biogéochimiques. Les résultats isotopiques montrent une différence saisonnière claire avec un impact fort de l’altération aux deux saisons. Les bassins versants du sud-ouest sont très différents des autres bassins du fait de leur topographie et climat. L’impact de l’agriculture et de la couverture forestière est aussi clairement présent dans tous les bassins tandis que la composition isotopique de Si des eaux souterraines résulte d’une combinaison de production et dissolution de minéraux. Ainsi, cette étude montre le rôle prépondérant de l’altération et du type d’argiles formées sur les isotopes de Si, indépendamment des saisons, plutôt que des processus biologiques ou de mélange tels que rapportés précédemment
Silicon is the second most abundant element in Earth’s crust and one of the key nutrient in aquatic ecosystems. There are strong interactions of Si with carbon cycle and biogeochemical processes. The present thesis focused on variability of silicon (amorphous-ASi, lithogenic-LSi and dissolved-DSi) and Si isotopes along the land to ocean continuum. We investigated the seasonal and spatial variability of ASi, LSi & DSi and Si isotopes in ~20 Indian estuaries. We categorize the estuaries using statistical analysis (PCA and cluster analysis). Diatom uptake seems to be the main process controlling ASi during dry period, especially in the South. Weathering and erosion control the variability of LSi in the remaining estuaries. Similarly lithogenic supply controls Si during wet period in all estuaries and no impact of diatoms was seen because of high suspended load. Si isotopic compositions trace the Si sources and biogeochemical pathways. The isotopic results exhibit clear seasonal difference with high impact of type of weathering during both seasons. They show that southwest watersheds are very special in terms of weathering regime compared to the other watersheds because of topography and climate. The impact of agriculture and forest cover on Si cycle is also clearly evidenced in all the basins during wet period. We show that groundwater Si isotopic variability results from a combination of dissolution and production of minerals. Overall, this study shows the preponderant influence of weathering and type of secondary clays on Si isotopes irrespective to the seasons, rather than the biological uptake or mixing as reported elsewhere
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Cockerton, Helen Elizabeth. « Late-glacial and Holocene variations in the Si cycle in the Nile Basin : multi-isotope evidence from modern waters and lake sediments ». Thesis, Swansea University, 2012. https://cronfa.swan.ac.uk/Record/cronfa42906.

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Coffineau, Nathalie. « Processus contrôlant la distribution des isotopes du silicium dissous (δ30Si) dans l'océan Atlantique et Indien ». Thesis, Brest, 2013. http://www.theses.fr/2013BRES0067/document.

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L'utilisation des isotopes du silicium (δ30Si) comme proxy paléocéanographique nécessite une bonne connaissance de la répartition et du devenir des isotopes du silicium à travers l'océan. Au cours des dernières années, des efforts considérables ont été faits pour cartographier la composition isotopique du silicium dissous (acide silicique, DSi) et de la silice biogénique (BSi) dans l'océan. Les diatomées utilisent le DSi pour construire leur frustule fait d’opale (BSi). Durant ce processus, les diatomées discriminent l'isotope lourd de silicium (30Si) en faveur de l'isotope léger (28Si). Ce fractionnement conduit à une BSi qui a un δ30Si inférieur de 1,1 ‰ à 1,5 ‰ par rapport au DSi source. Cela se traduit dans les eaux de surface par de faibles concentrations en DSi en raison de l'utilisation biologique et par des valeurs de δ30Si élevées en raison de la distillation de Rayleigh. Inversement, lorsque la BSi se dissout, il y a une discrimination contre l’isotope lourd et ainsi produit du silicium dissous avec un δ30Si inférieur de 0,55 ‰. Dans le même temps, la circulation océanique et le mélange vertical contribuent à modifier le δ30Si du pool de silicium dissous dans la couche de surface, ce qui complique l'utilisation du δ30Si des diatomées comme proxy pour l’utilisation du DSi durant la saison de croissance. Cette thèse vise à mieux comprendre les processus qui régissent le cycle du silicium et la signature en δ30Si des masses d'eau dans les différentes régions de l'océan. De nouvelles données de δ30Si de silicium dissous sont présentées et discutées. Ces données proviennent de 6 profiles CTD de la campagne ANTXXIII/9 (Atlantique et secteur indien de l'océan Austral), 7 profiles CTD de la campagne ANTXXIV/3 (secteur Atlantique de l'océan Austral), et 5 profiles CTD de la campagne MSM10/1 (région subtropical et tropical de l’océan Atlantique nord). Les échantillons ont été purifiés par chromatographie échangeuse d'ions après préconcentration par précipitation de Mg(OH)2, et le silicium est extrait en utilisant du triéthylamine molybdate. Les analyses isotopiques ont été réalisées sur Spectromètre de Masse Multi-Collection à source Plasma (MC-ICP-MS, Naptune) à moyenne résolution (Ifremer, Brest)
Use of silicon isotopes (δ30Si) as a paleoceanographic proxy requires sound knowledge of the distribution and behaviour of silicon isotopes throughout the ocean. Over the past few years considerable effort has been made to map the silicon isotope composition (δ30Si) of silicic acid (dissolved silicon, DSi) and biogenic silica (BSi) throughout the ocean. Diatoms uptake DSi to build up their opal frustules (BSi). During this process, diatoms discriminate against the heavier isotope of silicon (30Si) in favor of the light isotope (28Si). This fractionation leads to BSi that has a lower δ30Si than the DSi source by 1.1 ‰ to 1.5 ‰. In turn, this results in surface waters with low DSi concentrations due to biological removal, and high δ30Si values due to Rayleigh distillation. Conversely, when the BSi dissolves it is with discrimination against the heavier isotope producing dissolved silicon with a δ30Si lower by 0.55 ‰. At the same time, episodes of upwelling occurring throughout the growing season, ocean circulation and mixing, contribute to modify the δ30Si of the dissolved silicon pool in the surface mixed layer, which complicate the use of diatom δ30Si as a proxy for DSi removal during the growing season. This dissertation aims to better understand the processes driving the Si cycle and the δ30Si signature of water masses in different regions of the ocean. New data of δ30Si of dissolved Si are presented and discussed. These data come from 6 CTD profiles from ANTXXIII/9 campaign (Atlantic and Indian sector of the Southern Ocean), 7 CTD profiles from ANTXXIV/3 (Atlantic sector of the Southern Ocean), and 5 CTD profiles from the campaign MSM10/1 (north Subtropical and Tropical Atlantic Ocean). Samples were purified by ion-exchange chromatography following preconcentration via Mg(OH)2 precipitation and extraction of silicon using triethylamine molybdate. Isotopic analyses were carried on a Neptune MC-ICP-MS at medium resolution (Ifremer, Brest)
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Livres sur le sujet "Silicon cycle"

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Quéguiner, Bernard. The Biogeochemical Cycle of Silicon in the Ocean. Hoboken, NJ, USA : John Wiley & Sons, Inc., 2016. http://dx.doi.org/10.1002/9781119136880.

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1945-, Ittekkot V., dir. The silicon cycle : Human perturbations and impacts on aquatic systems. Washington, DC : Island Press, 2006.

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Cyclic plasticity and low cycle fatigue life of metals. Amsterdam : Elsevier, 1991.

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Gatti, Susanne. The rôle of sponges in high-Antarctic carbon and silicon cycling : A modelling approach = Die Rolle der Schwämme in hochantarktischen Kohlenstoff- und Silikatkreislauf : ein Modellierungsansatz. Bremerhaven : Alfred-Wegener-Institut für Polar- und Meeresforschung, 2002.

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S, Majumdar Bhaskar, et United States. National Aeronautics and Space Administration., dir. In-phase thermomechanical fatigue mechanisms in an unidirectional SCS-6/Ti 15-3 MMC. [Washington, DC] : National Aeronautics and Space Administration, 1995.

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S, Majumdar Bhaskar, et United States. National Aeronautics and Space Administration., dir. In-phase thermomechanical fatigue mechanisms in an unidirectional SCS-6/Ti 15-3 MMC. [Washington, DC] : National Aeronautics and Space Administration, 1995.

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S, Majumdar Bhaskar, et United States. National Aeronautics and Space Administration., dir. In-phase thermomechanical fatigue mechanisms in an unidirectional SCS-6/Ti 15-3 MMC. [Washington, DC] : National Aeronautics and Space Administration, 1995.

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Quéguiner, Bernard. Biogeochemical Cycle of Silicon in the Ocean. Wiley & Sons, Incorporated, John, 2016.

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Bernard Quéguiner. Biogeochemical Cycle of Silicon in the Ocean. Wiley & Sons, Incorporated, John, 2016.

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Qu�guiner, Bernard. Biogeochemical Cycle of Silicon in the Ocean. Wiley & Sons, Incorporated, John, 2016.

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Chapitres de livres sur le sujet "Silicon cycle"

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Shaha, S. K., F. Czerwinski, W. Kasprzak, J. Friedman et D. L. Chen. « Low Cycle Fatigue of Aluminum-Silicon Alloys for Power-Train Applications ». Dans TMS2015 Supplemental Proceedings, 999–1006. Hoboken, NJ, USA : John Wiley & Sons, Inc., 2015. http://dx.doi.org/10.1002/9781119093466.ch121.

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Shaha, S. K., F. Czerwinski, W. Kasprzak, J. Friedman et D. L. Chen. « Low Cycle Fatigue of Aluminum-Silicon Alloys for Power-Train Applications ». Dans TMS 2015 144th Annual Meeting & ; Exhibition, 999–1006. Cham : Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-48127-2_121.

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De La Rocha, Christina, et Daniel J. Conley. « The Venerable Silica Cycle ». Dans Silica Stories, 157–76. Cham : Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-54054-2_9.

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Shan, Jingsong, Chengfa Song, Shengbo Zhou, TongJun Duan, Shuai Zheng et Bo Zhang. « Study on Performance of Pervious Concrete Modified by Nano-Silicon + Polypropylene Fiber Composite ». Dans Lecture Notes in Civil Engineering, 189–98. Singapore : Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-1748-8_15.

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AbstractIn order to improve the comprehensive performance of pervious concrete, nano-silicon and polypropylene fiber were added to pervious concrete to study the change of performance of pervious concrete. Firstly, the effect of single doped nano-silicon on the properties of cement slurry and pervious concrete was studied, and the optimal water-binder ratio and nano-silicon content were determined. Based on this, mixed polypropylene fiber with different proportions of length of 18 mm to determine the reasonable amount of polypropylene fiber. The results showed that the compressive strength of pervious concrete was the highest when the nano-silicon content was 0.5% and the water-binder ratio was 0.32. Based on this ratio, the maximum compressive strength can be obtained by adding 1.0 kg/m3 polypropylene fiber, and the compressive strength of 7d and 28d increased by 29.9% and 42.2%, respectively. Adding 1.5 kg/m3 polypropylene fiber was the most beneficial to improve the freezing resistance of pervious concrete. For example, after 300 freeze–thaw cycles, the compressive strength residual rate was 62%. That's much higher than the 40 percent that was found when nano silicon was mixed alone.
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Shagwira, Harrison, Fredrick Madaraka Mwema et Thomas Ochuku Mbuya. « Life Cycle Analysis of Plastic ». Dans Polymer-Silica Based Composites in Sustainable Construction, 27–38. Boca Raton : CRC Press, 2021. http://dx.doi.org/10.1201/9781003231936-3.

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Gupta, Akshat, Anmol Srivastava et Vishnu Agarwal. « Biofilm Detachment and Its Implication in Spreading Biofilm-Related Infections ». Dans Proceedings of the Conference BioSangam 2022 : Emerging Trends in Biotechnology (BIOSANGAM 2022), 3–13. Dordrecht : Atlantis Press International BV, 2022. http://dx.doi.org/10.2991/978-94-6463-020-6_2.

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AbstractBiofilms are a community of microorganisms formed on both abiotic and biotic surfaces. These colonies play a vital role in the virulent life cycle of bacteria. Bacteria communicate intrinsically and extrinsically to grow and eventually disperse their virulent factors, ultimately leading to diseases. Biofilm dispersion is the last stage in this life cycle; at this stage, the biofilm has completed maturation. The microorganism then disperses as the biofilm ruptures and assumes a planktonic lifestyle until they find a new surface to attach to and repeat the cycle. This mechanism plays a vital role in the pathogenicity of the microorganism and can be triggered prematurely to disrupt the microorganism's virulent nature. In this mini-review, we have summarized biofilm dispersion, its mechanisms, and the factors influenced by, focusing on their effect on the pathogen's virulence. We have also discussed the significance of quorum sensing and the modern methods used to develop quorum sensing inhibitors through in-silico approaches.
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Cao, J., N. Gowripalan, V. Sirivivatnanon et J. Nairn. « Investigation of ASR Effects on the Load-Carrying Capacity of Reinforced Concrete Elements by Ultra-Accelerated Laboratory Test ». Dans Lecture Notes in Civil Engineering, 43–52. Singapore : Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-3330-3_7.

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AbstractThe alkali–silica reaction (ASR) can cause expansion, cracking, and degradation of the mechanical properties of affected concrete. Concerns about the safety of ASR-damaged reinforced concrete structures have driven the demand for studying the effects of ASR on residual load capacity of the deteriorated structure. Conventionally, field load testing methods are used to assess the residual load capacity of ASR-affected structures. In this study, a novel accelerated laboratory test using the LVSA 50/70 autoclave to accelerate ASR was applied to investigate the flexural and shear behavior of small-scale reinforced concrete beams affected by ASR. The specimens were subjected to three cycles of 80 °C steam curing at atmospheric pressure in the autoclave, with 60 h/cycle. Significant expansion and ASR damage were observed. Load carrying capacity tests on the small-scale reinforced concrete beams showed that, at the expansion levels achieved, the flexural capacity of the reinforced concrete beams was not significantly affected. Shear resistance of the reinforced concrete beams, however, was found to increase compared with their 28-day counterparts, which could be attributed to the prestressing effect due to ASR expansion. It appears that the multicycle 80 °C steam-curing autoclave test is suitable for investigating ASR deterioration of actual concrete mixes within a short period of time. ASR effects on the load carrying capacity of reinforced concrete elements at higher expansion levels, however, need further investigation.
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Le Jehan, S., et P. Tréguer. « The Distribution of Inorganic Nitrogen, Phosphorus, Silicon and Dissolved Organic Matter in Surface and Deep Waters of the Southern Ocean ». Dans Antarctic Nutrient Cycles and Food Webs, 22–29. Berlin, Heidelberg : Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/978-3-642-82275-9_4.

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Bezerra, A., C. Trottier, L. F. M. Sanchez et B. Fournier. « The use of artificial intelligence for assessing an overpass affected by Alkali-Silica Reaction (ASR) ». Dans Bridge Safety, Maintenance, Management, Life-Cycle, Resilience and Sustainability, 354–61. London : CRC Press, 2022. http://dx.doi.org/10.1201/9781003322641-40.

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Ragueneau, Olivier, Daniel J. Conley, Dave J. DeMaster, Hans H. Dürr et Nicolas Dittert. « Biogeochemical Transformations of Silicon Along the Land–Ocean Continuum and Implications for the Global Carbon Cycle1 ». Dans Global Change – The IGBP Series, 515–27. Berlin, Heidelberg : Springer Berlin Heidelberg, 2010. http://dx.doi.org/10.1007/978-3-540-92735-8_10.

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Actes de conférences sur le sujet "Silicon cycle"

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PHILLIPS, DENNIS R., RAPHAEL M. KUDELA, VIRGINIA T. HAMILTON et MARK A. BRZEZINSKI. « SILICON-32 : DIATOMS, THE SILICON CYCLE, AND THE CLIMATE ». Dans Proceedings of the 3rd International Conference on Isotopes. WORLD SCIENTIFIC, 2000. http://dx.doi.org/10.1142/9789812793867_0044.

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Peshkov, A. V. « BIM technologies : Organizational aspects at the stages of the life cycle of an investment and construction project ». Dans SiliconPV 2021, The 11th International Conference on Crystalline Silicon Photovoltaics. AIP Publishing, 2022. http://dx.doi.org/10.1063/5.0091559.

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Theillet, Pierre-Olivier, et Olivier Pierron. « Low-cycle fatigue testing of silicon resonators ». Dans SPIE MOEMS-MEMS : Micro- and Nanofabrication, sous la direction de Richard C. Kullberg et Rajeshuni Ramesham. SPIE, 2009. http://dx.doi.org/10.1117/12.808180.

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Laukert, Georgi, Stephanie Kienast, Tristan Horner, Kristin Doering, Patricia Grasse, Dorothea Bauch, Martin Frank, Oliver Huhn et Christian Mertens. « East Greenland’s rising impact on the marine silicon cycle constrained by silicon isotopes ». Dans Goldschmidt2022. France : European Association of Geochemistry, 2022. http://dx.doi.org/10.46427/gold2022.10247.

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Zhang, L. C. « The Stress-Dependence of Phase Changes in Silicon Under Indentation ». Dans World Tribology Congress III. ASMEDC, 2005. http://dx.doi.org/10.1115/wtc2005-63908.

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This paper investigates the stress effect on the phase transformation events in silicon under varying indentation loads, cycles and environment. It was found that the combination of hydrostatic and deviatoric stresses in indentation plays an important role. With a single indentation cycle, the deformed zone can be amorphous, a mixture of crystalline and amorphous, or purely crystalline, depending on the level of the maximum indentation load. Under cyclic indentations, some phases can be initiated from the second indentation cycle and stabilized in the subsequent cycles. Water has an obvious effect on the indentation deformation, with which silicon becomes less ductile. Different shapes of indenter tips leads to dissimilar phase transformation processes.
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Carlson, David R., Phillips Hutchison, Daniel D. Hickstein et Scott B. Papp. « Few-cycle pulses and ultraflat supercontinuum with silicon-nitride waveguides ». Dans CLEO : Science and Innovations. Washington, D.C. : OSA, 2019. http://dx.doi.org/10.1364/cleo_si.2019.sw4h.2.

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Lunardi, Marina M., J. P. Alvarez-Gaitan, Nathan L. Chang et Richard Corkish. « Life Cycle Assessment on Hydrogenation Processes on Silicon Solar Modules ». Dans 2018 IEEE 7th World Conference on Photovoltaic Energy Conversion (WCPEC) (A Joint Conference of 45th IEEE PVSC, 28th PVSEC & 34th EU PVSEC). IEEE, 2018. http://dx.doi.org/10.1109/pvsc.2018.8547848.

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Tréguer, Paul, Jill Sutton, Brzezinski Mark, Matt Charette, Timothy Devries, Stephanie Dutkiewicz, Claudia Ehlert et al. « Updating the biogeochemical cycle of silicon in the modern ocean ». Dans Goldschmidt2021. France : European Association of Geochemistry, 2021. http://dx.doi.org/10.7185/gold2021.4207.

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Magnani, Alessandro, Christophe Viallon, Ioan Burciu, Thomas Epert, Mattia Borgarino et Thierry Parra. « A K-band BiCMOS low duty-cycle resistive mixer ». Dans 2014 IEEE 14th Topical Meeting on Silicon Monolithic Integrated Circuits in Rf Systems (SiRF). IEEE, 2014. http://dx.doi.org/10.1109/sirf.2014.6828506.

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Bhattacharya, Arani, Subhasis Koley et Ansuman Banerjee. « Considering multi-cycle influences for signal selection for Post Silicon Validation ». Dans 2015 International Conference on Electronic Design, Computer Networks & Automated Verification (EDCAV). IEEE, 2015. http://dx.doi.org/10.1109/edcav.2015.7060559.

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Rapports d'organisations sur le sujet "Silicon cycle"

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Zhang, Jiguang, Qiuyan Li, Xiaolin Li, Wu Xu et Ran Yi. Silicon-Based Anodes for Long-Cycle-Life Lithium-ion Batteries. Office of Scientific and Technical Information (OSTI), août 2021. http://dx.doi.org/10.2172/2331443.

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Walker, Matthew, Warren York, Jeffrey Chames, Joshua Sugar, Kristen Frey, Herb Feinroth et Eric Barringer. Silicon Carbide Multilayer Piping for 900oC Supercritical CO2 Brayton Cycle : Chemical Compatibility in CO2. Office of Scientific and Technical Information (OSTI), mars 2019. http://dx.doi.org/10.2172/1761976.

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Brossia. L52119 Comparative Consumption Rates of Impressed Current Cathodic Protection Anodes. Chantilly, Virginia : Pipeline Research Council International, Inc. (PRCI), janvier 2004. http://dx.doi.org/10.55274/r0010953.

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Résumé :
There is a variety of impressed current anode materials available for onshore applications, including High Silicon Cast Iron (HSCI), Mixed Metal Oxides (MMO), graphite, platinum (or platinum coated titanium), and conductive polymers. Many end users simply select the anode material that they have experience with. What is lacking is a clear, direct comparison of relative anode consumption rates conducted under identical conditions. The present study examined the behavior of the various anode types under different current loads and soil conditions in an effort to establish baseline consumption rates under controlled conditions. Variables that were examined included soil resistivity, the presence of coke backfill, current load, and soil type (sand or 50/50 clay/sand mix). The consumption rates of the anodes evaluated decreased in the order of: AnodeFlex, HSCI, Graphite, Pt, and MMO. A survey of field experiences yielded a slightly different order in terms of anode life with Graphite and HSCI lasting the longest. However, given the wide range of anode sizes used in the various field sites, it is difficult to directly link the field results to the consumption rates measured in the laboratory. Soil composition and resistivity were not observed to have a significant influence on anode consumption rates. The presence of coke, however, led to a decrease in consumption for all anodes in some cases by as much as a factor of nearly 70. Utilizing anode cost estimates and neglecting installation costs, the life-cycle material costs for MMO and Pt anodes are much lower than the other anode materials. Furthermore, AnodeFlex was noted to be the highest cost system from a materials perspective. This may be slightly misleading since installation and replacement costs are not factored in. Given that the installation of AnodeFlex is often much easier and less expensive than the other anode types, this may prove to be a viable financial decision when the other factors are considered. ����������� The primary implications of the present study are: Despite higher material costs, MMO and Pt anodes may offer significant long-term cost savings as compared to other anode types for many applications Use of coke backfill is critical to ensure lower anode consumption rates for AnodeFlex, Graphite, and to a lesser extent HSCI; coke does not appear necessary for MMO or Pt Soil composition (sand vs. clay/sand mix) and resistivity do not appear to significantly influence anode consumption rates, thus consideration of the soil environment (except groundwater chemistry) is not needed in selection of an appropriate anode Because the influence of groundwater chemistry (as part of the soil environment) was not examined, the effects of sulfate, chloride, and pH will need to be evaluated in detail to better aid in anode material selection Field use survey responses showed a wide range in observed anode lifespan, with graphite and HSCI experiencing the longest life and cable anodes the shortest The field survey also revealed that a significant cause of anode failures was connector and cable problems
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