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Concept

Silice pyrogénée

Publications associées (32)

Modulating the Surface Properties of Lithium Niobate Nanoparticles by Multifunctional Coatings Using Water-in-Oil Microemulsions

Sandrine Gerber, Alessandra Spada, Adrian Stefan Gheata

Inorganic nanoparticles (NPs) have emerged as promising tools in biomedical applications, owing to their inherent physicochemical properties and their ease of functionalization. In all potential applications, the surface functionalization strategy is a key ...

2023

High-Density Immobilization of TCEP on Silica Beads for Efficient Disulfide Reduction and Thiol Alkylation in Peptides

Christian Heinis

Tris-(2-carboxyethyl)phosphine (TCEP) linked to agarose beads is widely used for reducing disulfide bridges in proteins and peptides. The immobilization of TCEP on beads allows efficient removal after reduction to prevent its reaction with alkylating reage ...

2023

Data-driven optimization tool for the functional, economic, and environmental properties of blended cement concrete using supplementary cementitious materials

Hisham Tarek Mohamed Hafez

The need to produce more sustainable concrete is proving imminent given the rising environmental concerns facing the industry. Blended cement concrete, based on any of the prominent supplementary cementitious materials (SCMs) such as fly ash, ground granul ...

ELSEVIER2023

Femtosecond laser-shockwave induced densification in fused silica

Yves Bellouard, Pieter Vlugter, Arunkrishnan Radhakrishnan, Julien Gilles Edgar Gateau

A tightly focused femtosecond laser-beam in the non-ablative regime can induce a shockwave sufficiently intense to reach local pressures in the giga-Pascal range or more. In a single beam configuration, the location of the highest-pressure zone is nested w ...

2022

Abnormal temperature dependent elastic properties of fused silica irradiated by ultrafast lasers

Yves Bellouard, Pieter Vlugter

Materials with thermal-invariant elastic properties are of interest for resonant device frequency and dimensional stability of precision devices. Here, we demonstrate that the temperature coefficient of elasticity (TCE) of amorphous silica can be locally r ...

2022

Effect of different ions on dissolution rates of silica and feldspars at high pH

Karen Scrivener, Mahsa Bagheri

The dissolution kinetics of silica-containing minerals in aggregates influences strongly the process of ASR in concrete. In this paper, the effect of different ions on the dissolution rates of SiO2 (amorphous and quartz) and feldspars at high pH values was ...

Pergamon-Elsevier Science Ltd2022

Effect of femtosecond laser-induced high pressure on fused silica polymorphism

Arunkrishnan Radhakrishnan

High-pressure studies in silica are of great interest to earth and planetary sciences. Highpressure phases are rarely found in nature as a result of shock events like meteorite impacts or volcanic events in nature. Recreating these phases remains a challen ...

EPFL2022

Pre-bcc: A novel integrated machine learning framework for predicting mechanical and durability properties of blended cement concrete

Hisham Tarek Mohamed Hafez

Partially replacing ordinary Portland cement (OPC) with low-carbon supplementary cementitious materials (SCMs) in blended cement concrete (BCC) is perceived as the most promising route for sustainable concrete production. Despite having a lower environment ...

ELSEVIER SCI LTD2022

The effect of paste composition, aggregate mineralogy and temperature on the pore solution composition and the extent of ASR expansion

Karen Scrivener, Mahsa Bagheri

The reaction kinetics of the alkali silica reaction depends on the composition of the pore solution. The evolution of the pore solution composition in different cement pastes and concretes was studied. Pastes containing silica fume or metakaolin had the lo ...

SPRINGER2022

Characterization of water sorption cycle in the cement microstructure of controlled oxide composition

Monisha Rastogi

This thesis investigates the water vapour sorption behaviour of samples with maximized calcium-silicate-hydrate (C-S-H) content. Primarily, the role of heterogeneous and homogeneous cavitation has been studied during the drying of cementitious materials. C ...

EPFL2022

Effect of alkali hydroxide on calcium silicate hydrate (C-S-H)

Karen Scrivener, Émilie Michèle L'Hôpital, Yu Yan

This paper investigates the effect of KOH and NaOH on C-S-H structure and solubility. Both KOH and NaOH have a similar effect, they increase pH values and silicon concentrations, and decrease calcium concentrations. At higher alkali hydroxide concentration ...

Pergamon-Elsevier Science Ltd2022

Strong silicon oxide inclusions in iron

Andreas Mortensen, Léa Deillon, Alejandra Inés Slagter, Joris Pierre Everaerts

Oxide inclusions are ubiquitous in steel and are known to affect, generally in a negative sense, the mechanical performance of steel products. Micromechanical properties of those phases are therefore important, yet they have remained largely unexplored. We ...

2022

Effect of alkali, aluminium and equilibration time on calcium-silicate-hydrates

Yu Yan, Yiru Yan

Calcium silicate hydrate (C-S-H) is the main hydration product in Portland and blended cements, and greatly affects durability and mechanical properties of the hydrated cement. In the presence of Al-rich supplementary cementitious materials (SCMs), C-(A-)S ...

EPFL2022

Efficient Meso-Scale Modeling of Alkali-Silica-Reaction Damage in Concrete

Ali Falsafi

The alkali-silica reaction (ASR), also known as concrete cancer, is one of the most prevalent causes of concrete degradation. In this chemical reaction, amorphous silica in the aggregates reacts with alkalis in the pore solution. By absorbing water, hydrop ...

EPFL2022

Grafting of Alkali Metals on Fumed Silica for the Catalytic Dehydrogenation of Methanol to Formaldehyde

Oliver Kröcher, Alimohammad Bahmanpour, Christophe Jean Baranowski

Water free, non-oxidative catalytic dehydrogenation of methanol to formaldehyde is an important process for the formation of anhydrous, molecular formaldehyde (FA). Sodium or sodium-containing salts were shown to catalyze the reaction, but their reaction m ...

Wiley-VCH Verlag2021

The effect of alkali hydroxides and equilibration time on Al uptake by calcium silicate hydrates (C-S-H)

Sonya Barzgar

Cement production accounts for approximately 8% of man-made CO2 emissions. Lowering these CO2 emissions is currently one of the most important and urgent research topics within the cement community. To reduce these emissions, the Portland cement (PC) is pa ...

EPFL2021

Aggregate dissolution in different pore solutions

Mahsa Bagheri

The occurrence of cracking due to alkali silica reaction (ASR) affects the service life of concrete structures. The dissolution of silica-containing minerals within aggregates causes the formation of ASR products, which fill macroscopic cracks and cause th ...

EPFL2021

Promoting Persistent Superionic Conductivity in Sodium Monocarba-closo-dodecaborate NaCB11H12 via Confinement within Nanoporous Silica

Mirjana Dimitrievska

Superionic phases of bulk anhydrous salts based on large cluster-like polyhedral (carba)borate anions are generally stable only well above room temperature, rendering them unsuitable as solid-state electrolytes in energy-storage devices that typically oper ...

AMER CHEMICAL SOC2021

The effect of sodium hydroxide on Al uptake by calcium silicate hydrates (C S H)

Christian Ludwig, Sonya Barzgar

To reduce the CO2 emissions from cement production, Portland cement (PC) is partially replaced by supplementary cementitious materials (SCM). Reactions of SCM with PC during hydration leads to the formation of CSH with more silicon and aluminum than in PC, ...

2020

The impact of synthetic amorphous silica (E 551) on differentiated Caco-2 cells, a model for the human intestinal epithelium

Heinrich Hofmann

For several decades, food-grade synthetic amorphous silica (SAS) have been used as a technological additive to reduce caking of food powders. Human exposure is thus inevitable and safety concerns are taken seriously. The toxicity of silica in general and S ...

PERGAMON-ELSEVIER SCIENCE LTD2020