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Paul Bowen

Cette personne a quitté l’EPFL

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Publications associées (92)

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Hardening acceleration/hardening retardation composition for building materials

Paul Bowen, Abhishek Kumar

Provided herein is a composition for use as a hardening regulator, e.g. hardening accelerator or hardening retarder, for building materials, as well as methods for producing thereof. The composition is characterized by a biphasic nature in which solid calc ...

2018

Phase Transformation and Densification of Nanostructured Alumina. Effect of Seeding and Doping

Paul Bowen

By following the densification kinetics of nanocrystalline γ alumina and corresponding microstructural evolution we showed that the diffusive transformation gamma-alpha involves several processes such as nucleation of alpha phase, rearrangement of gamma cr ...

2005

Catalytic activity of commercial of TiO2 powders for the abatement of the bacteria (E. coli) under solar simulated light: Influence of the isoelectric point

César Pulgarin, Paul Bowen, Juan Kiwi, Damien Gumy, Carlos Morais

Thirteen different commercial TiO2 powders with specific surface areas varying from 9 to 335 m/g and with isoelectric points (IEP) from 3 to 7.5 were investigated for their catalytic activity in E. coli inactivation. The TiO2 samples zeta potential, attenu ...

2006

pyCSH: Automated atomic-level structure generation of bulk C-S-H and investigation of their intrinsic properties

Karen Scrivener, Paul Bowen, Ziga Casar

A new Python code for the automated generation of realistic bulk calcium silicate hydrate (C-S-H) structures is introduced. The code was used to generate 400 structures with Ca/Si of 1.3, 1.5, 1.7, and 1.9. The generated structures are in excellent agreeme ...

Pergamon-Elsevier Science Ltd2024

Fabrication and Characterisation of Cathode Support-tubes for Micro-tubular SOFC Application

Jan Van Herle, Heinrich Hofmann, Paul Bowen, Stefan Diethelm, John Espen Rossen

Tubes of diameter

2009

Photocatalytic Storing of O2 as H2O2 Mediated by High Surface Area CuO. Evidence for a Reductive-Oxidative Interfacial Mechanism

Juan Kiwi, Paul Bowen, Lucica Soare

CuO powders with a high specific surface area are shown to be able to produce H2O2 in aqueous solution under simulated light irradiation. The highest rate of peroxide production was observed under mild experimental conditions using O2 and a large surface a ...

2005

Comparison of apparent activation energies for densification of alumina powders by pulsed electric current sintering (spark plasma sintering) and conventional sintering-toward applications for transparent polycrystalline alumina

Paul Bowen, Zhe Zhao, Michael Stuer

In the quest for high real in-line transmittances for transparent polycrystalline alumina (PCA), we need defect free processing. One of the biggest advances in producing high density defect free ceramics over recent years has been the advent of spark plasm ...

Materials Research Society2017

Atomistic modeling of dopant segregation in alpha-alumina ceramics: Coverage dependent energy of segregation and nominal dopant solubility

Paul Bowen, Ulrich Aschauer, Sandra Caroline Galmarini, Abhishek Tewari

Microstructural control is a key aspect in producing ceramics with tailored properties and is often achieved by using dopants in a rather empirical fashion. Atomic scale simulations could provide much needed insight but the long-standing challenge of linki ...

2011

Effect of particle size on LiMnPO4 cathodes

Paul Bowen, Nam Hee Kwon

LiMnPO4 was synthesized using a sol–gel method and tested as a cathode material for lithium ion batteries. After calcination at temperatures between 520 and 600 ◦C, primary particle sizes in the range of 140–220 nm were achieved. Subsequent dry ball millin ...

2007

Kinetics and Mechanism of Metal Nanoparticle Growth via Optical Extinction Spectroscopy and Computational Modeling: The Curious Case of Colloidal Gold

Paul Bowen, Andrea Testino, Mohammad Reza Andalibi

An overarching computational framework unifying several optical theories to describe the temporal evolution of gold nanoparticles (GNPs) during a seeded growth process is presented. To achieve this, we used the inexpensive and widely available optical exti ...

2019

Interaction of biologically relevant ions and organic molecules with titanium oxide (rutile) surfaces: A review on molecular dynamics studies

Paul Bowen, Ulrich Aschauer, Azade Yazdan Yar

The surface of a biomaterial can play a major role in its biological fate since the surface is the primary pathway for its interaction with the body. As the natural response of the body to a foreign material is to encapsulate it with a fibrous material, th ...

2018

Precipitation of Nanostructured Copper Oxalate: Substructure and Growth Mechanism

Heinrich Hofmann, Paul Bowen, Jacques Lemaître, Lucica Soare

The possibility of controlling materials properties by tailoring their substructure at the nanometer scale is a current topic of great interest. To do so, a fundamental understanding of the growth mechanism is of key importance and an analytical challenge ...

2006

A discussion on the paper "Role of porosity on the stiffness and stability of (001) surface of the nanogranular C-S-H gel"

Paul Bowen, Aslam Kunhi Mohamed

This paper is a discussion of a recent publication by Sekkal and coworkers, which investigated the elasticity, cohesion, and stability of the C-S-H (001) surface as a function of porosity using molecular dynamics simulations. In our discussion, we highligh ...

Pergamon-Elsevier Science Ltd2017

Chemically pure beta-tricalcium phosphate powders: Evidence of two crystal structures

Paul Bowen, Duncan Thomas Lindsay Alexander, Gabrielle Anne Laguisma Sblendorio

The question whether beta-tricalcium phosphate (beta-TCP) can form a solid solution with beta-calcium pyrophosphate (beta-CPP) and/or hydroxyapatite (HA) has still not been solved. For this reason, wet-chemically synthesized beta-TCP powders with only 20 p ...

ELSEVIER SCI LTD2021

Nanoparticles and method for producing uniform silicate-based nanoparticles

Paul Bowen, Abhishek Kumar

Nanoparticles and method for producing uniform silicate-based nanoparticles are disclosed. The method comprises a step of injecting into tubular branched elements comprising static mixers a first aqueous solution comprising a water-soluble silicate compoun ...

2018

Atomic-Level and Surface Structure of Calcium Silicate Hydrate Nanofoils

Karen Scrivener, Paul Bowen, Ziga Casar, Aslam Kunhi Mohamed

Deciphering the calcium silicate hydrate (C-S-H) surface is crucial for unraveling the mechanisms of cement hydration and property development. Experimental observations of C-S-H in cement systems suggest a surface termination which is fundamentally differ ...

AMER CHEMICAL SOC2023

How colloid-colloid interactions and hydrodynamic effects influence the percolation threshold: A simulation study in alumina suspensions

Paul Bowen

The percolation behavior of alumina suspensions is studied by computer simulations. The percolation threshold phi(c), is calculated, determining the key factors that affect its magnitude: the strength of colloid-colloid attraction and the presence of hydro ...

Elsevier2015

Yield stress modelling of doped alumina suspensions for applications in freeze granulation: towards dry pressed transparent ceramics

Paul Bowen, Michael Stuer

Rheology of powder suspensions is a key factor in many processing routes, and better understanding of the parameters that control the rheology improves technical progress by reducing the empirical factors in the formulation of powder slurries. The strict r ...

2012

Yield Stress of Multimodal Powder Suspensions: An Extension of the YODEL (Yield Stress mODEL)

Paul Bowen

The prediction of the rheological properties of concentrated suspensions is of great importance both in industrial processes (ceramics, cements, and pharmaceutics) and natural phenomena (debris flow, soil erosion). In a previous paper, we presented a new m ...

2007

Fabrication of large-area ordered arrays of nanoparticles on patterned substrates

Heinrich Hofmann, Paul Bowen, Frédéric Juillerat

Many potential applications in nanotechnology require virtually defect-free arrays of nanometre-scale particles over large areas. Guided self-assembly of colloidal particles on patterned templates has been shown to produce ordered arrays of colloidal parti ...

2005