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Paul Bowen

Cette personne a quitté l’EPFL

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Publications associées (92)

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Design and Function of Novel Superplasticizers for More Durable High Performance Concrete (Superplast Project)

Paul Bowen, François Perche

In this article we shall describe our quest and ultimate success in furthering our understanding of the action of superplasticizers on the rheology of cement and concrete. By specifically producing superplasticizers with varied architectures, we have been ...

Pergamon-Elsevier Science Ltd2008

Toward Knowledge-Based Grain-Boundary Engineering of Transparent Alumina Combining Advanced TEM and Atomistic Modeling

Cécile Hébert, Paul Bowen, Marco Cantoni, Farhang Nabiei, Michael Stuer, Abhishek Tewari

Transition element dopants (e.g., Y, La) are commonly used as sintering aids in polycrystalline alumina ceramics, which segregate to the grain boundaries and control the grain-boundary mobility. However, due to the extremely thin (

Wiley-Blackwell2015

Formation and Drying of Colloidal Crystals Using Nanosized Silica Particles

Heinrich Hofmann, Paul Bowen, Frédéric Juillerat

Much interest has been generated in the fabrication of colloidal crystals from suspensions because of the promise of photonic band gap applications. However, since the case of small, nonsedimenting colloidal particles indeed remains rather rarely treated, ...

2006

Cathode-supported micro-tubular SOFCs based on Nd1.95NiO4 + δ: Fabrication and characterisation of dip-coated electrolyte layers

Heinrich Hofmann, Jan Van Herle, Paul Bowen, Josef Andreas Schuler, Ulrich Aschauer, Henning Lübbe

Fabrication conditions to obtain dense electrolyte double layers on a porous micro-tubular cathode substrate were investigated. Porous tubes of a nickelate material, Nd1.95NiO4 + δ, were fabricated by cold-isostatic pressing (CIP) and sintering. Thin ﬁlms ...

2009

Molecular dynamic simulations of cementitious systems using a newly developed force field suite ERICA FF

Paul Bowen, Ziga Casar, Masood Valavi

A force field suite, ERICA FF has been developed for the simulation of cementitious systems. It has been validated for structural, energetic and mechanical properties. It covers the species Ca, OH, sulfate, water, Si, Al, Na, K and Cl. We have simulated st ...

Pergamon-Elsevier Science Ltd2022

Surface and Mirror Twin Grain Boundary Segregation in Nd:YAG: An Atomistic Simulation Study

Paul Bowen, Ulrich Aschauer

Ceramic lasers have advantages such as better optical homogeneity, cheaper production, and more freedom in shape compared with monocrystalline lasers. However, equal or better laser performances are required. Interface segregation is important as ceramics ...

2008

Understanding of the factors slowing down metakaolin reaction in limestone calcined clay cement (LC3) at late ages

Karen Scrivener, Paul Bowen, Mohsen Ben Haha, François Henri Avet, Yosra Briki

Factors which could explain the slowing down of the metakaolin reaction in LC3 blends are investigated. Portlandite availability and the presence of aluminium ions in the pore solution are shown not to be limiting factors. ...

Pergamon-Elsevier Science Ltd2021

Impact of pore solution composition and superplasticizers on the interparticle forces and rheology of metakaolin suspensions

Paul Bowen

This study focuses on the influence of pH, aqueous phase composition and superplasticizers on the particle interactions in pure metakaolin suspensions. It was found increasing pH up to 11 led to the decrease of the particle agglomeration due to the higher ...

2025

Phosphorescent compounds

Paul Bowen

Phosphorescent composition comprises an alkaline earth metal silicate doped with europium fluoride and another lanthanide fluoride. Independent claims are also included for: (1) producing a composition as above by grinding a mixture of alkaline earth metal ...

2007

Spark Plasma Sintering of Ceramics: From Modeling to Practice

Paul Bowen, Michael Stuer, Zhe Zhao

Summarizing the work of nearly a decade of research on spark plasma sintering (SPS), a review is given on the specificities and key factors to be considered in SPS of ceramic materials, based on the authors’ own research. Alumina is used primarily as a mod ...

2020

Continuous Production of Tailored Silver Nanoparticles by Polyol Synthesis and Reaction Yield Measured by X-ray Absorption Spectroscopy: Toward a Growth Mechanism

Christian Ludwig, Heinrich Hofmann, Paul Bowen, Frank Nüesch, Andrea Testino, Jose Enrico Quijano Quinsaat

Two complementary topics are discussed: (i) the continuous production of silver nanoparticles (AgNPs) and (ii) the measurement of reaction yield by X-ray absorption near-edge spectroscopy (XANES). The continuous polyol synthesis of AgNPs in grams amount an ...

Amer Chemical Soc2014

Predicting the yield stress of paraffin-wax suspensions

Paul Bowen

An empirical modification of the Yodel model was developed for the prediction of the yield stress of concentrated, particulate, paraffin-wax suspensions, with a solids loading in the range of 47-57 vol.%, used in the low-pressure injection moulding (LPIM). ...

Elsevier2016

Segregation of anion (Cl−) impurities at transparent polycrystalline α-alumina interfaces

Cécile Hébert, Paul Bowen, Marco Cantoni, Farhang Nabiei, Abhishek Tewari

Small amounts of anion impurities (e.g. Cl), which are incorporated during the synthesis of ceramic powders, can affect the properties and microstructure of the final sintered ceramic. The effect of anion impurities is a little studied and poorly understoo ...

Elsevier Sci Ltd2014

New approach to low thermal conductivity of thermal barrier protection with improved mechanical integrity

Heinrich Hofmann, Paul Bowen, Abhishek Tewari

Layered ceramic systems with designed stacks of dense and porous layers were investigated as alternative for thermal barrier protection system (TBPs). This approach gives the possibility to obtain low thermal conductivity with the impact protection of dens ...

Elsevier2016

Grain Growth in Doped Oxide Ceramics: From Nanosizes Powders and Atomistic Simulations to Tailored Interfaces

Paul Bowen, Ulrich Aschauer, Sandra Caroline Galmarini

Swansea Materials Research Centre2006

Colloidal Processing and Yield Stress Modeling Towards Dry Pressed Green Bodies for Transparent Polycrystalline Alumina

Paul Bowen, Michael Stuer

Colloidal processing is a key aspect in modern ceramic processing but most formulations are found empirically. The need for a better knowledge based design of suspension formulation can be achieved by using interparticle potential modelling linked to rheol ...

Wiley-Blackwell2014

Cathodoluminescent screen imaging system for seeded blob detection in toroidal plasma experiment

Ambrogio Fasoli, Ivo Furno, Paolo Ricci, Paul Bowen, Marcelo Baquero Ruiz, Fabian Manke, Carlos Morais, Paolo Micheletti

We designed and built a diagnostic based on a cathodoluminescent screen for the detection of turbulent plasma structures with high spatial resolution. The screen is coated with a low threshold energy cathodoluminescent powder that emits light when exposed ...

2020

Towards tailored superplasticizers

Paul Bowen, François Perche

Superplasticizers (SP) of the “new generation” are essentially polycarboxylate polymers. Polymers of this family can be produced with almost infinite variations in their chemical structure, which allow the fulfilment of specific (tailored) properties. Thes ...

2005

cemff: A force field database for cementitious materials including validations, applications and opportunities

Paul Bowen, Sandra Caroline Galmarini, Aslam Kunhi Mohamed, David Geissbühler

This paper reviews atomistic force field parameterizations for molecular simulations of cementitious minerals, such as tricalcium silicate (C3S), portlandite (CH), tobermorites (model C-S-H). Computational techniques applied to these materials include clas ...

Pergamon-Elsevier Science Ltd2017

Atomistic Modeling Study of Surface Segregation in Nd:YAG

Paul Bowen, Ulrich Aschauer

This study investigates the composition of free surfaces of neodymium-doped yttrium–aluminum–garnet, using energy minimization techniques. Atomistic modeling shows that the dopant is concentrated in a zone within 0.5 nm ̊of the surface, the enrichment fact ...

2006